Walking in School-Aged Children in a Dual-Task Paradigm Is Related to Age But Not to Cognition, Motor Behavior, Injuries, or Psychosocial Functioning

PubMed Central

Hagmann-von Arx, Priska; Manicolo, Olivia; Lemola, Sakari; Grob, Alexander

2016-01-01

Age-dependent gait characteristics and associations with cognition, motor behavior, injuries, and psychosocial functioning were investigated in 138 typically developing children aged 6.7–13.2 years (M = 10.0 years). Gait velocity, normalized velocity, and variability were measured using the walkway system GAITRite without an additional task (single task) and while performing a motor or cognitive task (dual task). Assessment of children’s cognition included tests for intelligence and executive functions; parents reported on their child’s motor behavior, injuries, and psychosocial functioning. Gait variability (an index of gait regularity) decreased with increasing age in both single- and dual-task walking. Dual-task gait decrements were stronger when children walked in the motor compared to the cognitive dual-task condition and decreased with increasing age in both dual-task conditions. Gait alterations from single- to dual-task conditions were not related to children’s cognition, motor behavior, injuries, or psychosocial functioning. PMID:27014158

Motor-cognitive dual-task deficits in individuals with early-mid stage Huntington disease.

PubMed

Fritz, Nora E; Hamana, Katy; Kelson, Mark; Rosser, Anne; Busse, Monica; Quinn, Lori

2016-09-01

Huntington disease (HD) results in a range of cognitive and motor impairments that progress throughout the disease stages; however, little research has evaluated specific dual-task abilities in this population, and the degree to which they may be related to functional ability. The purpose of this study was to a) examine simple and complex motor-cognitive dual-task performance in individuals with HD, b) determine relationships between dual-task walking ability and disease-specific measures of motor, cognitive and functional ability, and c) examine the relationship of dual-task measures to falls in individuals with HD. Thirty-two individuals with HD were evaluated for simple and complex dual-task ability using the Walking While Talking Test. Demographics and disease-specific measures of motor, cognitive and functional ability were also obtained. Individuals with HD had impairments in simple and complex dual-task ability. Simple dual-task walking was correlated to disease-specific motor scores as well as cognitive performance, but complex dual-task walking was correlated with total functional capacity, as well as a range of cognitive measures. Number of prospective falls was moderately-strongly correlated to dual-task measures. Our results suggest that individuals with HD have impairments in cognitive-motor dual-task ability that are related to disease progression and specifically functional ability. Dual-task measures appear to evaluate a unique construct in individuals with early to mid-stage HD, and may have value in improving the prediction of falls risk in this population. Copyright © 2016 Elsevier B.V. All rights reserved.

Does the walking task matter? Influence of different walking conditions on dual-task performances in young and older persons.

PubMed

Beurskens, Rainer; Bock, Otmar

2013-12-01

Previous literature suggests that age-related deficits of dual-task walking are particularly pronounced with second tasks that require continuous visual processing. Here we evaluate whether the difficulty of the walking task matters as well. To this end, participants were asked to walk along a straight pathway of 20m length in four different walking conditions: (a) wide path and preferred pace; (b) narrow path and preferred pace, (c) wide path and fast pace, (d) obstacled wide path and preferred pace. Each condition was performed concurrently with a task requiring visual processing or fine motor control, and all tasks were also performed alone which allowed us to calculate the dual-task costs (DTC). Results showed that the age-related increase of DTC is substantially larger with the visually demanding than with the motor-demanding task, more so when walking on a narrow or obstacled path. We attribute these observations to the fact that visual scanning of the environment becomes more crucial when walking in difficult terrains: the higher visual demand of those conditions accentuates the age-related deficits in coordinating them with a visual non-walking task. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Can Dual Task Walking Improve in Parkinson's Disease After External Focus of Attention Exercise? A Single Blind Randomized Controlled Trial.

PubMed

Beck, Eric N; Intzandt, Brittany N; Almeida, Quincy J

2018-01-01

It may be possible to use attention-based exercise to decrease demands associated with walking in Parkinson's disease (PD), and thus improve dual task walking ability. For example, an external focus of attention (focusing on the effect of an action on the environment) may recruit automatic control processes degenerated in PD, whereas an internal focus (limb movement) may recruit conscious (nonautomatic) control processes. Thus, we aimed to investigate how externally and internally focused exercise influences dual task walking and symptom severity in PD. Forty-seven participants with PD were randomized to either an Externally (n = 24) or Internally (n = 23) focused group and completed 33 one-hour attention-based exercise sessions over 11 weeks. In addition, 16 participants were part of a control group. Before, after, and 8 weeks following the program (pre/post/washout), gait patterns were measured during single and dual task walking (digit-monitoring task, ie, walking while counting numbers announced by an audio-track), and symptom severity (UPDRS-III) was assessed ON and OFF dopamine replacement. Pairwise comparisons (95% confidence intervals [CIs]) and repeated-measures analyses of variance were conducted. Pre to post: Dual task step time decreased in the external group (Δ = 0.02 seconds, CI 0.01-0.04). Dual task step length (Δ = 2.3 cm, CI 0.86-3.75) and velocity (Δ = 4.5 cm/s, CI 0.59-8.48) decreased (became worse) in the internal group. UPDRS-III scores (ON and OFF) decreased (improved) in only the External group. Pre to washout: Dual task step time ( P = .005) and percentage in double support ( P = .014) significantly decreased (improved) in both exercise groups, although only the internal group increased error on the secondary counting task (ie, more errors monitoring numbers). UPDRS-III scores in both exercise groups significantly decreased ( P = .001). Since dual task walking improvements were found immediately, and 8 weeks after the cessation of an externally focused exercise program, we conclude that externally focused exercise may improve on functioning of automatic control networks in PD. Internally focused exercise hindered dual tasking ability. Overall, externally focused exercise led to greater rehabilitation benefits in dual tasking and motor symptoms compared with internally focused exercise.

The Effects of a Secondary Task on Forward and Backward Walking in Parkinson Disease

PubMed Central

Hackney, Madeleine E.; Earhart, Gammon M.

2009-01-01

Background People with Parkinson disease (PD) often fall while multi-tasking or walking backward, unavoidable activities in daily living. Dual tasks involving cognitive demand during gait and unfamiliar motor skills like backward walking could identify those with fall risk, but dual tasking while walking backward has not been examined in those with PD, those who experience Freezing of Gait (FOG), or healthy older controls. Methods Seventy-eight people with PD (mean age = 65.1±9.5 years, Female: 28%) and 74 age- and sex-matched controls (mean age = 65.0±10.0 years, Female: 23%) participated. A computerized walkway measured gait velocity, stride length, swing and stance percent, cadence, heel to heel base of support, functional ambulation profile, and gait asymmetry during forward and backward walking with and without a secondary cognitive task. Results Direction and task effects on walking performance were similar between healthy controls and those with PD. However, those with PD were more affected than controls, and freezers were more affected than non-freezers, by backward walking and dual tasking. Walking backward seemed to impact gait more than dual tasking in those with PD, although the subset of freezers appeared particularly impacted by both challenges. Conclusion People with PD are impaired while performing complex motor and mental tasks simultaneously, which may put them at risk for falling. Those with FOG are more adversely affected by both motor and mental challenges than those without. Evaluation of backward walking while performing a secondary task might be an effective clinical tool to identify locomotor difficulties. PMID:19675121

Characterization of cognitive and motor performance during dual-tasking in healthy older adults and patients with Parkinson's disease.

PubMed

Wild, Lucia Bartmann; de Lima, Daiane Borba; Balardin, Joana Bisol; Rizzi, Luana; Giacobbo, Bruno Lima; Oliveira, Henrique Bianchi; de Lima Argimon, Irani Iracema; Peyré-Tartaruga, Leonardo Alexandre; Rieder, Carlos R M; Bromberg, Elke

2013-02-01

The primary purpose of this study was to investigate the effect of dual-tasking on cognitive performance and gait parameters in patients with idiopathic Parkinson's disease (PD) without dementia. The impact of cognitive task complexity on cognition and walking was also examined. Eighteen patients with PD (ages 53-88, 10 women; Hoehn and Yahr stage I-II) and 18 older adults (ages 61-84; 10 women) completed two neuropsychological measures of executive function/attention (the Stroop Test and Wisconsin Card Sorting Test). Cognitive performance and gait parameters related to functional mobility of stride were measured under single (cognitive task only) and dual-task (cognitive task during walking) conditions with different levels of difficulty and different types of stimuli. In addition, dual-task cognitive costs were calculated. Although cognitive performance showed no significant difference between controls and PD patients during single or dual-tasking conditions, only the patients had a decrease in cognitive performance during walking. Gait parameters of patients differed significantly from controls at single and dual-task conditions, indicating that patients gave priority to gait while cognitive performance suffered. Dual-task cognitive costs of patients increased with task complexity, reaching significantly higher values then controls in the arithmetic task, which was correlated with scores on executive function/attention (Stroop Color-Word Page). Baseline motor functioning and task executive/attentional load affect the performance of cognitive tasks of PD patients while walking. These findings provide insight into the functional strategies used by PD patients in the initial phases of the disease to manage dual-task interference.

Smartphone App-Based Assessment of Gait During Normal and Dual-Task Walking: Demonstration of Validity and Reliability.

PubMed

Manor, Brad; Yu, Wanting; Zhu, Hao; Harrison, Rachel; Lo, On-Yee; Lipsitz, Lewis; Travison, Thomas; Pascual-Leone, Alvaro; Zhou, Junhong

2018-01-30

Walking is a complex cognitive motor task that is commonly completed while performing another task such as talking or making decisions. Gait assessments performed under normal and "dual-task" walking conditions thus provide important insights into health. Such assessments, however, are limited primarily to laboratory-based settings. The objective of our study was to create and test a smartphone-based assessment of normal and dual-task walking for use in nonlaboratory settings. We created an iPhone app that used the phone's motion sensors to record movements during walking under normal conditions and while performing a serial-subtraction dual task, with the phone placed in the user's pants pocket. The app provided the user with multimedia instructions before and during the assessment. Acquired data were automatically uploaded to a cloud-based server for offline analyses. A total of 14 healthy adults completed 2 laboratory visits separated by 1 week. On each visit, they used the app to complete three 45-second trials each of normal and dual-task walking. Kinematic data were collected with the app and a gold-standard-instrumented GAITRite mat. Participants also used the app to complete normal and dual-task walking trials within their homes on 3 separate days. Within laboratory-based trials, GAITRite-derived heel strikes and toe-offs of the phone-side leg aligned with smartphone acceleration extrema, following filtering and rotation to the earth coordinate system. We derived stride times-a clinically meaningful metric of locomotor control-from GAITRite and app data, for all strides occurring over the GAITRite mat. We calculated stride times and the dual-task cost to the average stride time (ie, percentage change from normal to dual-task conditions) from both measurement devices. We calculated similar metrics from home-based app data. For these trials, periods of potential turning were identified via custom-developed algorithms and omitted from stride-time analyses. Across all detected strides in the laboratory, stride times derived from the app and GAITRite mat were highly correlated (P<.001, r 2 =.98). These correlations were independent of walking condition and pocket tightness. App- and GAITRite-derived stride-time dual-task costs were also highly correlated (P<.001, r 2 =.95). The error of app-derived stride times (mean 16.9, SD 9.0 ms) was unaffected by the magnitude of stride time, walking condition, or pocket tightness. For both normal and dual-task trials, average stride times derived from app walking trials demonstrated excellent test-retest reliability within and between both laboratory and home-based assessments (intraclass correlation coefficient range .82-.94). The iPhone app we created enabled valid and reliable assessment of stride timing-with the smartphone in the pocket-during both normal and dual-task walking and within both laboratory and nonlaboratory environments. Additional work is warranted to expand the functionality of this tool to older adults and other patient populations. ©Brad Manor, Wanting Yu, Hao Zhu, Rachel Harrison, On-Yee Lo, Lewis Lipsitz, Thomas Travison, Alvaro Pascual-Leone, Junhong Zhou. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 30.01.2018.

Smartphone App–Based Assessment of Gait During Normal and Dual-Task Walking: Demonstration of Validity and Reliability

PubMed Central

Yu, Wanting; Zhu, Hao; Harrison, Rachel; Lo, On-Yee; Lipsitz, Lewis; Travison, Thomas; Pascual-Leone, Alvaro; Zhou, Junhong

2018-01-01

Background Walking is a complex cognitive motor task that is commonly completed while performing another task such as talking or making decisions. Gait assessments performed under normal and “dual-task” walking conditions thus provide important insights into health. Such assessments, however, are limited primarily to laboratory-based settings. Objective The objective of our study was to create and test a smartphone-based assessment of normal and dual-task walking for use in nonlaboratory settings. Methods We created an iPhone app that used the phone’s motion sensors to record movements during walking under normal conditions and while performing a serial-subtraction dual task, with the phone placed in the user’s pants pocket. The app provided the user with multimedia instructions before and during the assessment. Acquired data were automatically uploaded to a cloud-based server for offline analyses. A total of 14 healthy adults completed 2 laboratory visits separated by 1 week. On each visit, they used the app to complete three 45-second trials each of normal and dual-task walking. Kinematic data were collected with the app and a gold-standard–instrumented GAITRite mat. Participants also used the app to complete normal and dual-task walking trials within their homes on 3 separate days. Within laboratory-based trials, GAITRite-derived heel strikes and toe-offs of the phone-side leg aligned with smartphone acceleration extrema, following filtering and rotation to the earth coordinate system. We derived stride times—a clinically meaningful metric of locomotor control—from GAITRite and app data, for all strides occurring over the GAITRite mat. We calculated stride times and the dual-task cost to the average stride time (ie, percentage change from normal to dual-task conditions) from both measurement devices. We calculated similar metrics from home-based app data. For these trials, periods of potential turning were identified via custom-developed algorithms and omitted from stride-time analyses. Results Across all detected strides in the laboratory, stride times derived from the app and GAITRite mat were highly correlated (P<.001, r2=.98). These correlations were independent of walking condition and pocket tightness. App- and GAITRite-derived stride-time dual-task costs were also highly correlated (P<.001, r2=.95). The error of app-derived stride times (mean 16.9, SD 9.0 ms) was unaffected by the magnitude of stride time, walking condition, or pocket tightness. For both normal and dual-task trials, average stride times derived from app walking trials demonstrated excellent test-retest reliability within and between both laboratory and home-based assessments (intraclass correlation coefficient range .82-.94). Conclusions The iPhone app we created enabled valid and reliable assessment of stride timing—with the smartphone in the pocket—during both normal and dual-task walking and within both laboratory and nonlaboratory environments. Additional work is warranted to expand the functionality of this tool to older adults and other patient populations. PMID:29382625

Dual tasking negatively impacts obstacle avoidance abilities in post-stroke individuals with visuospatial neglect: Task complexity matters!

PubMed

Aravind, Gayatri; Lamontagne, Anouk

2017-01-01

Persons with perceptual-attentional deficits due to visuospatial neglect (VSN) after a stroke are at a risk of collisions while walking in the presence of moving obstacles. The attentional burden of performing a dual-task may further compromise their obstacle avoidance performance, putting them at a greater risk of collisions. The objective of this study was to compare the ability of persons with (VSN+) and without VSN (VSN-) to dual task while negotiating moving obstacles. Twenty-six stroke survivors (13 VSN+, 13 VSN-) were assessed on their ability to (a) negotiate moving obstacles while walking (locomotor single task); (b) perform a pitch-discrimination task (cognitive single task) and (c) simultaneously perform the walking and cognitive tasks (dual task). We compared the groups on locomotor (collision rates, minimum distance from obstacle and onset of strategies) and cognitive (error rates) outcomes. For both single and dual task walking, VSN+ individuals showed higher collision rates compared to VSN- individuals. Dual tasking caused deterioration of locomotor (more collisions, delayed onset and smaller minimum distances) and cognitive performances (higher error rate) in VSN+ individuals. Contrastingly, VSN- individuals maintained collision rates, increased minimum distance, but showed more cognitive errors, prioritizing their locomotor performance. Individuals with VSN demonstrate cognitive-locomotor interference under dual task conditions, which could severely compromise safety when ambulating in community environments and may explain the poor recovery of independent community ambulation in these individuals.

Do we always prioritize balance when walking? Towards an integrated model of task prioritization.

PubMed

Yogev-Seligmann, Galit; Hausdorff, Jeffrey M; Giladi, Nir

2012-05-01

Previous studies suggest that strategies such as "posture first" are implicitly employed to regulate safety when healthy adults walk while simultaneously performing another task, whereas "posture second" may be inappropriately applied in the presence of neurological disease. However, recent understandings raise questions about the traditional resource allocation concept during walking while dual tasking. We propose a task prioritization model of walking while dual tasking that integrates motor and cognitive capabilities, focusing on postural reserve, hazard estimation, and other individual intrinsic factors. The proposed prioritization model provides a theoretical foundation for future studies and a framework for the development of interventions designed to reduce the profound negative impacts of dual tasking on gait and fall risk in patients with neurological diseases. © 2012 Movement Disorder Society. Copyright © 2012 Movement Disorder Society.

Associations between cognitive and gait performance during single- and dual-task walking in people with Parkinson disease.

PubMed

Stegemöller, Elizabeth L; Wilson, Jonathan P; Hazamy, Audrey; Shelley, Mack C; Okun, Michael S; Altmann, Lori J P; Hass, Chris J

2014-06-01

Cognitive impairments in Parkinson disease (PD) manifest as deficits in speed of processing, working memory, and executive function and attention abilities. The gait impairment in PD is well documented to include reduced speed, shortened step lengths, and increased step-to-step variability. However, there is a paucity of research examining the relationship between overground walking and cognitive performance in people with PD. This study sought to examine the relationship between both the mean and variability of gait spatiotemporal parameters and cognitive performance across a broad range of cognitive domains. A cross-sectional design was used. Thirty-five participants with no dementia and diagnosed with idiopathic PD completed a battery of 12 cognitive tests that yielded 3 orthogonal factors: processing speed, working memory, and executive function and attention. Participants completed 10 trials of overground walking (single-task walking) and 5 trials of overground walking while counting backward by 3's (dual-task walking). All gait measures were impaired by the dual task. Cognitive processing speed correlated with stride length and walking speed. Executive function correlated with step width variability. There were no significant associations with working memory. Regression models relating speed of processing to gait spatiotemporal variables revealed that including dual-task costs in the model significantly improved the fit of the model. Participants with PD were tested only in the on-medication state. Different characteristics of gait are related to distinct types of cognitive processing, which may be differentially affected by dual-task walking due to the pathology of PD. © 2014 American Physical Therapy Association.

Older Adults Pay an Additional Cost When Texting and Walking: Effects of Age, Environment, and Use of Mixed Reality on Dual-Task Performance.

PubMed

Krasovsky, Tal; Weiss, Patrice L; Kizony, Rachel

2018-04-06

Texting while walking (TeWW) has become common among people of all ages, and mobile phone use during gait is increasingly associated with pedestrian injury. Although dual-task walking performance is known to decline with age, data regarding the effect of age on dual-task performance in ecological settings are limited. The objective of this study was to evaluate the effect of age, environment (indoors/outdoors), and mixed reality (merging of real and virtual environments) on TeWW performance. A cross-sectional design was used. Young (N = 30; 27.8 ± 4.4 years) and older (N = 20; 68.9 ± 3.9 years) adults performed single and dual-task texting and walking indoors and outdoors, with and without a mixed reality display. Participants also completed evaluations of visual scanning and cognitive flexibility (Trail Making Test) and functional mobility (Timed Up and Go). Indoors, similar interference to walking and texting occurred for both groups, but only older adults' gait variability increased under dual task conditions. Outdoors, TeWW was associated with larger age-related differences in gait variability, texting accuracy, and gait dual-task costs. Young adults with better visual scanning and cognitive flexibility performed TeWW with lower gait costs (r = 0.52 to r = 0.65). The mixed reality display was unhelpful and did not modify walking or texting. Older adults tested in this study were relatively high-functioning. Gaze of participants was not directly monitored. Although young and older adults possess the resources necessary for TeWW, older adults pay an additional "price" when dual-tasking, especially outdoors. TeWW may have potential as an ecologically-valid assessment and/or an intervention paradigm for dual task performance among older adults as well as for clinical populations.

Deep white matter hyperintensities, microstructural integrity and dual task walking in older people.

PubMed

Ghanavati, Tabassom; Smitt, Myriam Sillevis; Lord, Stephen R; Sachdev, Perminder; Wen, Wei; Kochan, Nicole A; Brodaty, Henry; Delbaere, Kim

2018-01-03

To examine neural, physiological and cognitive influences on gait speed under single and dual-task conditions. Sixty-two community-dwelling older people (aged 80.0 ± 4.2 years) participated in our study. Gait speed was assessed with a timed 20-meter walk under single and dual-task (reciting alternate letters of the alphabet) conditions. Participants also underwent tests to estimate physiological fall risk based on five measures of sensorimotor function, cognitive function across five domains, brain white matter (WM) hyperintensities and WM microstructural integrity by measuring fractional anisotropy (FA). Univariate linear regression analyses showed that global physiological and cognitive measures were associated with single (β = 0.594 and β=-0.297, respectively) and dual-task gait speed (β = 0.306 and β=-0.362, respectively). Deep WMHs were associated with dual-task gait speed only (β = 0.257). Multivariate mediational analyses showed that global and executive cognition reduced the strength of the association between deep WMHs and dual-task gait speed by 27% (β = 0.188) and 44% (β = 0.145) respectively. There was a significant linear association between single-task gait speed and mean FA values of the genu (β=-0.295) and splenium (β=-0.326) of the corpus callosum, and between dual-task gait speed and mean FA values of Superior Cerebellar Peduncle (β=-0.284), splenium of the Corpus Callosum (β=-0.286) and Cingulum (β=-0.351). Greater deep WMH volumes are associated with slower walking speed under dual-task conditions, and this relationship is mediated in part by global cognition and executive abilities specifically. Furthermore, both cerebellum and cingulum are related to dual-task walking due to their role in motor skill performance and attention, respectively.

Effects of Aging on Arm Swing during Gait: The Role of Gait Speed and Dual Tasking.

PubMed

Mirelman, Anat; Bernad-Elazari, Hagar; Nobel, Tomer; Thaler, Avner; Peruzzi, Agnese; Plotnik, Meir; Giladi, Nir; Hausdorff, Jeffrey M

2015-01-01

Healthy walking is characterized by pronounced arm swing and axial rotation. Aging effects on gait speed, stride length and stride time variability have been previously reported, however, less is known about aging effects on arm swing and axial rotation and their relationship to age-associated gait changes during usual walking and during more challenging conditions like dual tasking. Sixty healthy adults between the ages of 30-77 were included in this study designed to address this gap. Lightweight body fixed sensors were placed on each wrist and lower back. Participants walked under 3 walking conditions each of 1 minute: 1) comfortable speed, 2) walking while serially subtracting 3's (Dual Task), 3) walking at fast speed. Aging effects on arm swing amplitude, range, symmetry, jerk and axial rotation amplitude and jerk were compared between decades of age (30-40; 41-50; 51-60; 61-77 years). As expected, older adults walked slower (p = 0.03) and with increased stride variability (p = 0.02). Arm swing amplitude decreased with age under all conditions (p = 0.04). In the oldest group, arm swing decreased during dual task and increased during the fast walking condition (p<0.0001). Similarly, arm swing asymmetry increased during the dual task in the older groups (p<0.004), but not in the younger groups (p = 0.67). Significant differences between groups and within conditions were observed in arm swing jerk (p<0.02), axial rotation amplitude (p<0.02) and axial jerk (p<0.001). Gait speed, arm swing amplitude of the dominant arm, arm swing asymmetry and axial rotation jerk were all independent predictors of age in a multivariate model. These findings suggest that the effects of gait speed and dual tasking on arm swing and axial rotation during walking are altered among healthy older adults. Follow-up work is needed to examine if these effects contribute to reduced stability in aging.

Effects of Aging on Arm Swing during Gait: The Role of Gait Speed and Dual Tasking

PubMed Central

Mirelman, Anat; Bernad-Elazari, Hagar; Nobel, Tomer; Thaler, Avner; Peruzzi, Agnese; Plotnik, Meir; Giladi, Nir; Hausdorff, Jeffrey M.

2015-01-01

Healthy walking is characterized by pronounced arm swing and axial rotation. Aging effects on gait speed, stride length and stride time variability have been previously reported, however, less is known about aging effects on arm swing and axial rotation and their relationship to age-associated gait changes during usual walking and during more challenging conditions like dual tasking. Sixty healthy adults between the ages of 30–77 were included in this study designed to address this gap. Lightweight body fixed sensors were placed on each wrist and lower back. Participants walked under 3 walking conditions each of 1 minute: 1) comfortable speed, 2) walking while serially subtracting 3’s (Dual Task), 3) walking at fast speed. Aging effects on arm swing amplitude, range, symmetry, jerk and axial rotation amplitude and jerk were compared between decades of age (30–40; 41–50; 51–60; 61–77 years). As expected, older adults walked slower (p = 0.03) and with increased stride variability (p = 0.02). Arm swing amplitude decreased with age under all conditions (p = 0.04). In the oldest group, arm swing decreased during dual task and increased during the fast walking condition (p<0.0001). Similarly, arm swing asymmetry increased during the dual task in the older groups (p<0.004), but not in the younger groups (p = 0.67). Significant differences between groups and within conditions were observed in arm swing jerk (p<0.02), axial rotation amplitude (p<0.02) and axial jerk (p<0.001). Gait speed, arm swing amplitude of the dominant arm, arm swing asymmetry and axial rotation jerk were all independent predictors of age in a multivariate model. These findings suggest that the effects of gait speed and dual tasking on arm swing and axial rotation during walking are altered among healthy older adults. Follow-up work is needed to examine if these effects contribute to reduced stability in aging. PMID:26305896

The role of gender in the association between personality and task priority in older adults' dual-tasking while walking.

PubMed

Agmon, Maayan; Armon, Galit; Denesh, Shani; Doumas, Mihalis

2018-01-02

Falls are a major problem for older adults. Many falls occur when a person's attention is divided between two tasks, such as a dual task (DT) involving walking. Most recently, the role of personality in walking performance was addressed; however, its association with DT performance remains to be determined. This cross-sectional study of 73 older, community-dwelling adults explores the association between personality and DT walking and the role of gender in this relationship. Personality was evaluated using the five-factor model. Single-task (ST) and DT assessment of walking-cognitive DT performance comprised a 1-min walking task and an arithmetic task performed separately (ST) and concurrently (DT). Dual-task costs (DTCs), reflecting the proportional difference between ST and DT performance, were also calculated. Gender plays a role in the relationship between personality and DT. Extraversion was negatively associated with DTC-motor for men (ΔR 2  = 0.06, p < 0.05). Conscientiousness was positively associated with DTC-cognition for women (ΔR 2  = 0.08, p < 0.01). These findings may lead to effective personality-based early detection and intervention for fall prevention.

Effects of Practice on Task Architecture: Combined Evidence from Interference Experiments and Random-Walk Models of Decision Making

ERIC Educational Resources Information Center

Kamienkowski, Juan E.; Pashler, Harold; Dehaene, Stanislas; Sigman, Mariano

2011-01-01

Does extensive practice reduce or eliminate central interference in dual-task processing? We explored the reorganization of task architecture with practice by combining interference analysis (delays in dual-task experiment) and random-walk models of decision making (measuring the decision and non-decision contributions to RT). The main delay…

Measuring treatment effects on dual-task performance: a framework for research and clinical practice

PubMed Central

Plummer, Prudence; Eskes, Gail

2015-01-01

The relevance of dual-task walking to everyday ambulation is widely acknowledged, and numerous studies have demonstrated that dual-task interference can significantly impact recovery of functional walking in people with neurological disorders. The magnitude and direction of dual-task interference is influenced by the interaction between the two tasks, including how individuals spontaneously prioritize their attention. Therefore, to accurately interpret and characterize dual-task interference and identify changes over time, it is imperative to evaluate single and dual-task performance in both tasks, as well as the tasks relative to each other. Yet, reciprocal dual-task effects (DTE) are frequently ignored. The purpose of this perspective paper is to present a framework for measuring treatment effects on dual-task interference, specifically taking into account the interactions between the two tasks and how this can provide information on whether overall dual-task capacity has improved or a different attentional strategy has been adopted. In discussing the clinical implications of using this framework, we provide specific examples of using this method and provide some explicit recommendations for research and clinical practice. PMID:25972801

Changes in dual-task performance after 5 months of karate and fitness training for older adults to enhance fall prevention.

PubMed

Pliske, Gerald; Emmermacher, Peter; Weinbeer, Veronika; Witte, Kerstin

2016-12-01

Demographic changes resulting in an aging population are major factors for an increase of fall-related injuries. Especially in situations where dual tasks such as walking whilst talking have to be performed simultaneously the risk of a fall-related injury increases. It is well known that some types of martial art (e.g. Tai Chi) can reduce the risk of a fall. It is unknown if the same is true for karate. In this randomized, controlled study 68 people with a mean age of 69 years underwent 5-month karate training, 5-month fitness training or were part of a control group. Before and after the time of intervention a gait analysis with normal walk, a cognitive dual task and a motor dual task were performed. The gait parameter step frequency, walking speed, single-step time and single-step length were investigated. It could be seen that all groups improved their gait parameters after a 5-month period, even the control group. A sporty intervention seems to affect mainly the temporal gait parameters positively. This effect was especially demonstrated for normal walk and cognitive dual task. An improvement of the human walk seems to be possible through karate and fitness training, even under dual-task conditions. A prolonged intervention time with multiple repetitions of gait analysis could give better evidence if karate is a useful tool to increase fall prevention.

Functional implications of muscle co-contraction during gait in advanced age.

PubMed

Lo, Justine; Lo, On-Yee; Olson, Erin A; Habtemariam, Daniel; Iloputaife, Ikechukwu; Gagnon, Margaret M; Manor, Brad; Lipsitz, Lewis A

2017-03-01

Older adults often exhibit high levels of lower extremity muscle co-contraction, which may be the cause or effect of age-related impairments in gait and associated falls. Normal gait requires intact executive function and thus can be slowed by challenging executive resources available to the neuromuscular system through the performance of a dual task. We therefore investigated associations between lower limb co-contraction and gait characteristics under normal and dual task conditions in healthy older adults (85.4±5.9years). We hypothesized that greater co-contraction is associated with slower gait speed during dual task conditions that stress executive and attentional abilities. Co-contraction was quantified during different phases of the gait cycle using surface electromyography (EMG) signals obtained from the anterior tibialis and lateral gastrocnemius while walking at preferred speed during normal and dual task conditions. Variables included the time difference to complete the Trail Making Test A and B (ΔTMT) and gait measures during normal or dual task walking. Higher co-contraction levels during the swing phase of both normal and dual task walking were associated with longer ΔTMT (normal: R 2 =0.25, p=0.02; dual task: R 2 =0.27, p=0.01). Co-contraction was associated with gait measures during dual task walking only; greater co-contraction levels during stride and stance were associated with slower gait speed (stride: R 2 =0.38, p=0.04; stance: R 2 =0.38, p=0.04), and greater co-contraction during stride was associated with longer stride time (R 2 =0.16, p=0.03). Our results suggest that relatively high lower limb co-contraction may explain some of the mobility impairments associated with the conduct of executive tasks in older adults. Copyright © 2017 Elsevier B.V. All rights reserved.

Virtual Reality Training with Cognitive Load Improves Walking Function in Chronic Stroke Patients.

PubMed

Cho, Ki Hun; Kim, Min Kyu; Lee, Hwang-Jae; Lee, Wan Hee

2015-08-01

Virtual reality training is considered as an effective intervention method of stroke patients, and the virtual reality system for therapeutic rehabilitation has emphasized the cognitive factors to improve walking function. The purpose of current study was to investigate the effect of virtual reality training with cognitive load (VRTCL) on walking function of chronic stroke. Chronic stroke patients were randomly assigned to the VRTCL group (11 patients, including 5 men; mean age, 60.0 years; post-stroke duration, 273.9 days) or control group (11 patients, including 2 men; mean age, 58.6 years; post-stroke duration, 263.9 days). All subjects participated in the standard rehabilitation program that consisted of physical and occupational therapies. In addition, VRTCL group participated in the VRTCL for 4 weeks (30 min per day and five times a week), while those in the control group participated in virtual reality treadmill training. Walking function under single (walking alone) and dual task (walking with cognitive tasks) conditions was assessed using an electrical walkway system. After the 4-week intervention, under both single and dual task conditions, significant improvement on walking function was observed in VRTCL and control groups (P < 0.05). In addition, in the dual task condition, greater improvement on walking function was observed in the VRTCL group, compared with the control group (P < 0.05). These findings demonstrated the efficacy of VRTCL on the walking function under the dual task condition. Therefore, we suggest that VRTCL may be an effective method for the achievement of independent walking in chronic stroke patients.

Gait performance is not influenced by working memory when walking at a self-selected pace.

PubMed

Grubaugh, Jordan; Rhea, Christopher K

2014-02-01

Gait performance exhibits patterns within the stride-to-stride variability that can be indexed using detrended fluctuation analysis (DFA). Previous work employing DFA has shown that gait patterns can be influenced by constraints, such as natural aging or disease, and they are informative regarding a person's functional ability. Many activities of daily living require concurrent performance in the cognitive and gait domains; specifically working memory is commonly engaged while walking, which is considered dual-tasking. It is unknown if taxing working memory while walking influences gait performance as assessed by DFA. This study used a dual-tasking paradigm to determine if performance decrements are observed in gait or working memory when performed concurrently. Healthy young participants (N = 16) performed a working memory task (automated operation span task) and a gait task (walking at a self-selected speed on a treadmill) in single- and dual-task conditions. A second dual-task condition (reading while walking) was included to control for visual attention, but also introduced a task that taxed working memory over the long term. All trials involving gait lasted at least 10 min. Performance in the working memory task was indexed using five dependent variables (absolute score, partial score, speed error, accuracy error, and math error), while gait performance was indexed by quantifying the mean, standard deviation, and DFA α of the stride interval time series. Two multivariate analyses of variance (one for gait and one for working memory) were used to examine performance in the single- and dual-task conditions. No differences were observed in any of the gait or working memory dependent variables as a function of task condition. The results suggest the locomotor system is adaptive enough to complete a working memory task without compromising gait performance when walking at a self-selected pace.

Changes in step-width during dual-task walking predicts falls.

PubMed

Nordin, E; Moe-Nilssen, R; Ramnemark, A; Lundin-Olsson, L

2010-05-01

The aim was to evaluate whether gait pattern changes between single- and dual-task conditions were associated with risk of falling in older people. Dual-task cost (DTC) of 230 community living, physically independent people, 75 years or older, was determined with an electronic walkway. Participants were followed up each month for 1 year to record falls. Mean and variability measures of gait characteristics for 5 dual-task conditions were compared to single-task walking for each participant. Almost half (48%) of the participants fell at least once during follow-up. Risk of falling increased in individuals where DTC for performing a subtraction task demonstrated change in mean step-width compared to single-task walking. Risk of falling decreased in individuals where DTC for carrying a cup and saucer demonstrated change compared to single-task walking in mean step-width, mean step-time, and step-length variability. Degree of change in gait characteristics related to a change in risk of falling differed between measures. Prognostic guidance for fall risk was found for the above DTCs in mean step-width with a negative likelihood ratio of 0.5 and a positive likelihood ratio of 2.3, respectively. Findings suggest that changes in step-width, step-time, and step-length with dual tasking may be related to future risk of falling. Depending on the nature of the second task, DTC may indicate either an increased risk of falling, or a protective strategy to avoid falling. Copyright 2010. Published by Elsevier B.V.

Older adults must hurry at pedestrian lights! A cross-sectional analysis of preferred and fast walking speed under single- and dual-task conditions

PubMed Central

Tomovic, Sara; Münzer, Thomas; de Bruin, Eling D.

2017-01-01

Slow walking speed is strongly associated with adverse health outcomes, including cognitive impairment, in the older population. Moreover, adequate walking speed is crucial to maintain older pedestrians’ mobility and safety in urban areas. This study aimed to identify the proportion of Swiss older adults that didn’t reach 1.2 m/s, which reflects the requirements to cross streets within the green–yellow phase of pedestrian lights, when walking fast under cognitive challenge. A convenience sample, including 120 older women (65%) and men, was recruited from the community (88%) and from senior residences and divided into groups of 70–79 years (n = 59, 74.8 ± 0.4 y; mean ± SD) and ≥80 years (n = 61, 85.5 ± 0.5 y). Steady state walking speed was assessed under single- and dual-task conditions at preferred and fast walking speed. Additionally, functional lower extremity strength (5-chair-rises test), subjective health rating, and retrospective estimates of fall frequency were recorded. Results showed that 35.6% of the younger and 73.8% of the older participants were not able to walk faster than 1.2 m/s under the fast dual-task walking condition. Fast dual-task walking speed was higher compared to the preferred speed single- and dual-task conditions (all p < .05, r = .31 to .48). Average preferred single-task walking speed was 1.19 ± 0.24 m/s (70–79 y) and 0.94 ± 0.27 m/s (≥80 y), respectively, and correlated with performance in the 5-chair-rises test (rs = −.49, p < .001), subjective health (τ = .27, p < .001), and fall frequency (τ = −.23, p = .002). We conclude that the fitness status of many older people is inadequate to safely cross streets at pedestrian lights and maintain mobility in the community’s daily life in urban areas. Consequently, training measures to improve the older population’s cognitive and physical fitness should be promoted to enhance walking speed and safety of older pedestrians. PMID:28759587

Dual-task training effects on motor and cognitive functional abilities in individuals with stroke: a systematic review.

PubMed

He, Ying; Yang, Lei; Zhou, Jing; Yao, Liqing; Pang, Marco Yiu Chung

2018-02-01

This systematic review aimed to examine the effects of dual-task balance and mobility training in people with stroke. An extensive electronic databases literature search was conducted using MEDLINE, PubMed, EBSCO, The Cochrane Library, Web of Science, SCOPUS, and Wiley Online Library. Randomized controlled studies that assessed the effects of dual-task training in stroke patients were included for the review (last search in December 2017). The methodological quality was evaluated using the Cochrane Collaboration recommendation, and level of evidence was determined according to the criteria described by the Oxford Center for Evidence-Based Medicine. About 13 articles involving 457 participants were included in this systematic review. All had substantial risk of bias and thus provided level IIb evidence only. Dual-task mobility training was found to induce more improvement in single-task walking function (standardized effect size = 0.14-2.24), when compared with single-task mobility training. Its effect on dual-task walking function was not consistent. Cognitive-motor balance training was effective in improving single-task balance function (standardized effect size = 0.27-1.82), but its effect on dual-task balance ability was not studied. The beneficial effect of dual-task training on cognitive function was provided by one study only and thus inconclusive. There is some evidence that dual-task training can improve single-task walking and balance function in individuals with stroke. However, any firm recommendation cannot be made due to the weak methodology of the studies reviewed.

Home-based interventions improve trained, but not novel, dual-task balance performance in older adults: A randomized controlled trial.

PubMed

Wongcharoen, Suleeporn; Sungkarat, Somporn; Munkhetvit, Peeraya; Lugade, Vipul; Silsupadol, Patima

2017-02-01

The purpose of this study was to compare the efficacy of four different home-based interventions on dual-task balance performance and to determine the generalizability of the four trainings to untrained tasks. Sixty older adults, aged 65 and older, were randomly assigned to one of four home-based interventions: single-task motor training, single-task cognitive training, dual-task motor-cognitive training, and dual-task cognitive-cognitive training. Participants received 60-min individualized training sessions, 3 times a week for 4 weeks. Prior to and following the training program, participants were asked to walk under two single-task conditions (i.e. narrow walking and obstacle crossing) and two dual-task conditions (i.e. a trained narrow walking while performing verbal fluency task and an untrained obstacle crossing while counting backward by 3s task). A nine-camera motion capture system was used to collect the trajectories of 32 reflective markers placed on bony landmarks of participants. Three-dimensional kinematics of the whole body center of mass and base of support were computed. Results from the extrapolated center of mass displacement indicated that motor-cognitive training was more effective than the single-task motor training to improve dual-task balance performance (p=0.04, ES=0.11). Interestingly, balance performance under both single-task and dual-task conditions can also be improved through a non-motor, single-task cognitive training program (p=0.01, ES=0.13, and p=0.01, ES=0.11, respectively). However, improved dual-task processing skills during training were not transferred to the novel dual task (p=0.15, ES=0.09). This is the first study demonstrating that home-based dual-task training can be effectively implemented to improve balance performance during gait in older adults. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of narrow-base walking and dual tasking on gait spatiotemporal characteristics in anterior cruciate ligament-injured adults compared to healthy adults.

PubMed

Mazaheri, Masood; Negahban, Hossein; Soltani, Maryam; Mehravar, Mohammad; Tajali, Shirin; Hessam, Masumeh; Salavati, Mahyar; Kingma, Idsart

2017-08-01

The present experiment was conducted to examine the hypothesis that challenging control through narrow-base walking and/or dual tasking affects ACL-injured adults more than healthy control adults. Twenty male ACL-injured adults and twenty healthy male adults walked on a treadmill at a comfortable speed under two base-of-support conditions, normal-base versus narrow-base, with and without a cognitive task. Gait patterns were assessed using mean and variability of step length and mean and variability of step velocity. Cognitive performance was assessed using the number of correct counts in a backward counting task. Narrow-base walking resulted in a larger decrease in step length and a more pronounced increase in variability of step length and of step velocity in ACL-injured adults than in healthy adults. For most of the gait parameters and for backward counting performance, the dual-tasking effect was similar between the two groups. ACL-injured adults adopt a more conservative and more unstable gait pattern during narrow-base walking. This can be largely explained by deficits of postural control in ACL-injured adults, which impairs gait under more balance-demanding conditions. The observation that the dual-tasking effect did not differ between the groups may be explained by the fact that walking is an automatic process that involves minimal use of attentional resources, even after ACL injury. Clinicians should consider the need to include aspects of terrain complexity, such as walking on a narrow walkway, in gait assessment and training of patients with ACL injury. III.

The effects of a concurrent task on walking in persons with transfemoral amputation compared to persons without limb loss.

PubMed

Morgan, Sara J; Hafner, Brian J; Kelly, Valerie E

2016-08-01

Many people with lower limb loss report the need to concentrate on walking. This may indicate increased reliance on cognitive resources when walking compared to individuals without limb loss. This study quantified changes in walking associated with addition of a concurrent cognitive task in persons with transfemoral amputation using microprocessor knees compared to age- and sex-matched controls. Observational, cross-sectional study. Quantitative motion analysis was used to assess walking under both single-task (walking alone) and dual-task (walking while performing a cognitive task) conditions. Primary outcomes were walking speed, step width, step time asymmetry, and cognitive task response latency and accuracy. Repeated-measures analysis of variance was used to examine the effects of task (single-task and dual-task) and group (transfemoral amputation and control) for each outcome. No significant interactions between task and group were observed (all p > 0.11) indicating that a cognitive task did not differentially affect walking between groups. However, walking was slower with wider steps and more asymmetry in people with transfemoral amputation compared to controls under both conditions. Although there were significant differences in walking between people with transfemoral amputation and matched controls, the effects of a concurrent cognitive task on walking were similar between groups. The addition of a concurrent task did not differentially affect walking outcomes in people with and without transfemoral amputation. However, compared to people without limb loss, people with transfemoral amputation adopted a conservative walking strategy. This strategy may reduce the need to concentrate on walking but also contributed to notable gait deviations. © The International Society for Prosthetics and Orthotics 2015.

Resting State Default Mode Network Connectivity, Dual Task Performance, Gait Speed, and Postural Sway in Older Adults with Mild Cognitive Impairment

PubMed Central

Crockett, Rachel A.; Hsu, Chun Liang; Best, John R.; Liu-Ambrose, Teresa

2017-01-01

Aging is associated with an increased risk of falling. In particular, older adults with mild cognitive impairment (MCI) are more vulnerable to falling compared with their healthy counterparts. Major contributors to this increased falls risk include a decline in dual task performance, gait speed, and postural sway. Recent evidence highlights the potential influence of the default mode network (DMN), the frontoparietal network (FPN), and the supplementary motor area (SMA) on dual task performance, gait speed, and postural sway. The DMN is active during rest and deactivates during task-oriented processes, to maintain attention and stay on task. The FPN and SMA are involved in top-down attentional control, motor planning, and motor execution. The DMN shows less deactivation during task in older adults with MCI. This lack of deactivation is theorized to increase competition for resources between the DMN and task-related brain regions (e.g., the FPN and SMA), increasing distraction from the task and reducing task performance. However, no study has yet investigated the relationship between the between-network connectivity of the DMN with these regions and dual task walking, gait speed or postural sway. We hypothesized that greater functional connectivity both within the DMN and between DMN–FPN and DMN–SMA, will be associated with poorer performance during dual task walking, slower gait speed, and greater postural sway in older adults with MCI. Forty older adults with MCI were measured on a dual task-walking paradigm, gait speed over a 4-m walk, and postural sway using a sway-meter. Greater within-DMN connectivity was significantly correlated with poorer dual task performance. Furthermore, greater inter-network connectivity between the DMN and SMA was significantly correlated with slower gait speed and greater postural sway on the eyes open floor sway task. Thus, greater resting state DMN functional connectivity may be an underlying neural mechanism for reduced dual task ability, slower gait speed, and greater postural sway, resulting in the increased risk of mobility disability and falling in older adults with MCI. PMID:29311906

Resting State Default Mode Network Connectivity, Dual Task Performance, Gait Speed, and Postural Sway in Older Adults with Mild Cognitive Impairment.

PubMed

Crockett, Rachel A; Hsu, Chun Liang; Best, John R; Liu-Ambrose, Teresa

2017-01-01

Aging is associated with an increased risk of falling. In particular, older adults with mild cognitive impairment (MCI) are more vulnerable to falling compared with their healthy counterparts. Major contributors to this increased falls risk include a decline in dual task performance, gait speed, and postural sway. Recent evidence highlights the potential influence of the default mode network (DMN), the frontoparietal network (FPN), and the supplementary motor area (SMA) on dual task performance, gait speed, and postural sway. The DMN is active during rest and deactivates during task-oriented processes, to maintain attention and stay on task. The FPN and SMA are involved in top-down attentional control, motor planning, and motor execution. The DMN shows less deactivation during task in older adults with MCI. This lack of deactivation is theorized to increase competition for resources between the DMN and task-related brain regions (e.g., the FPN and SMA), increasing distraction from the task and reducing task performance. However, no study has yet investigated the relationship between the between-network connectivity of the DMN with these regions and dual task walking, gait speed or postural sway. We hypothesized that greater functional connectivity both within the DMN and between DMN-FPN and DMN-SMA, will be associated with poorer performance during dual task walking, slower gait speed, and greater postural sway in older adults with MCI. Forty older adults with MCI were measured on a dual task-walking paradigm, gait speed over a 4-m walk, and postural sway using a sway-meter. Greater within-DMN connectivity was significantly correlated with poorer dual task performance. Furthermore, greater inter-network connectivity between the DMN and SMA was significantly correlated with slower gait speed and greater postural sway on the eyes open floor sway task. Thus, greater resting state DMN functional connectivity may be an underlying neural mechanism for reduced dual task ability, slower gait speed, and greater postural sway, resulting in the increased risk of mobility disability and falling in older adults with MCI.

Minimum toe clearance events in divided attention treadmill walking in older and young adults: a cross-sectional study.

PubMed

Santhiranayagam, Braveena K; Lai, Daniel T H; Sparrow, W A; Begg, Rezaul K

2015-07-12

Falls in older adults during walking frequently occur while performing a concurrent task; that is, dividing attention to respond to other demands in the environment. A particularly hazardous fall-related event is tripping due to toe-ground contact during the swing phase of the gait cycle. The aim of this experiment was to determine the effects of divided attention on tripping risk by investigating the gait cycle event Minimum Toe Clearance (MTC). Fifteen older adults (mean 73.1 years) and 15 young controls (mean 26.1 years) performed three walking tasks on motorized treadmill: (i) at preferred walking speed (preferred walking), (ii) while carrying a glass of water at a comfortable walking speed (dual task walking), and (iii) speed-matched control walking without the glass of water (control walking). Position-time coordinates of the toe were acquired using a 3 dimensional motion capture system (Optotrak NDI, Canada). When MTC was present, toe height at MTC (MTC_Height) and MTC timing (MTC_Time) were calculated. The proportion of non-MTC gait cycles was computed and for non-MTC gait cycles, toe-height was extracted at the mean MTC_Time. Both groups maintained mean MTC_Height across all three conditions. Despite greater MTC_Height SD in preferred gait, the older group reduced their variability to match the young group in dual task walking. Compared to preferred speed walking, both groups attained MTC earlier in dual task and control conditions. The older group's MTC_Time SD was greater across all conditions; in dual task walking, however, they approximated the young group's SD. Non-MTC gait cycles were more frequent in the older group across walking conditions (for example, in preferred walking: young - 2.9 %; older - 18.7 %). In response to increased attention demands older adults preserve MTC_Height but exercise greater control of the critical MTC event by reducing variability in both MTC_Height and MTC_Time. A further adaptive locomotor control strategy to reduce the likelihood of toe-ground contacts is to attain higher mid-swing clearance by eliminating the MTC event, i.e. demonstrating non-MTC gaits cycles.

Return to activity after concussion affects dual-task gait balance control recovery.

PubMed

Howell, David R; Osternig, Louis R; Chou, Li-Shan

2015-04-01

Recent work has identified deficits in dual-task gait balance control for up to 2 months after adolescent concussion; however, how resumption of preinjury physical activities affects recovery is unknown. The objective of this study is to examine how return to activity (RTA) affects recovery from concussion on measures of symptom severity, cognition, and balance control during single-task and dual-task walking. Nineteen adolescents with concussion who returned to preinjury activity within 2 months after injury and 19 uninjured, matched controls completed symptom inventories, computerized cognitive testing, and single-task and dual-task gait analyses. Concussion participants were assessed at five time points: within 72 h, 1 wk, 2 wk, 1 month, and 2 months postinjury. Control participants were assessed at the same time points as their matched concussion counterparts. RTA day was documented as the postinjury day in which physical activity participation was allowed. The effect of returning to physical activity was assessed by examining the percent change on each dependent variable across time before and directly after the RTA. Data were analyzed by two-way mixed effects ANOVAs. After the RTA day, concussion participants significantly increased their total center-of-mass medial/lateral displacement (P = 0.009, ηp = .175) and peak velocity (P = 0.048, ηp = 0.104) during dual-task walking when compared with pre-RTA data, whereas no changes for the concussion group or between groups were detected on measures of single-task walking, forward movement, or cognition. Adolescents with concussion displayed increased center-of-mass medial/lateral displacement and velocity during dual-task walking after RTA, suggesting a regression of recovery in gait balance control. This study reinforces the need for a multifaceted approach to concussion management and continued monitoring beyond the point of clinical recovery.

Dual Task Gait Performance in Frail Individuals with and without Mild Cognitive Impairment.

PubMed

Martínez-Ramírez, Alicia; Martinikorena, Ion; Lecumberri, Pablo; Gómez, Marisol; Millor, Nora; Casas-Herrero, Alvaro; Zambom-Ferraresi, Fabrício; Izquierdo, Mikel

2016-01-01

Several studies have stated that frailty is associated with cognitive impairment. Based on various studies, cognition impairment has been considered as a component of frailty. Other authors have shown that physical frailty is associated with low cognitive performance. Dual task gait tests are used as a strong predictor of falls in either dementia or frailty. Consequently, it is important to investigate dual task walking tests in elderly populations including control robust oldest old, frail oldest old with mild cognitive impairment (MCI) and frail oldest old without MCI. Dual task walking tests were carried out to examine the association between frailty and cognitive impairment in a population with advanced age. Forty-one elderly men and women participated in this study. The subjects from control, frail with MCI and frail without MCI groups, completed the 5-meter walk test at their own gait velocity. Arithmetic and verbal dual task walking performance was also assessed. Kinematic data were acquired from a unique tri-axial inertial sensor. The spatiotemporal and frequency parameters related to gait disorders did not show any significant differences between frail with and without MCI groups. The evaluation of these parameters extracted from the acceleration signals led us to conclude that these results expand the knowledge regarding the common conditions in frailty and MCI and may highlight the idea that the impairment in walking performance does not depend of frailty and cognitive status. © 2016 S. Karger AG, Basel.

The impact of walking while using a smartphone on pedestrians' awareness of roadside events.

PubMed

Lin, Ming-I Brandon; Huang, Yu-Ping

2017-04-01

Previous studies have shown that using a cell phone to talk or text while walking changes gait kinematics and encourages risky street-crossing behaviors. However, less is known about how the motor-cognitive interference imposed by smartphone tasks affects pedestrians' situational awareness to environmental targets relevant to pedestrian safety. This study systematically investigated the influence of smartphone use on detection of and responses to a variety of roadside events in a semi-virtual walking environment. Twenty-four healthy participants completed six treadmill walking sessions while engaged in a concurrent picture-dragging, texting, or news-reading task. During distracted walking, they were required to simultaneously monitor the occurrence of road events for two different levels of event frequency. Performance measures for smartphone tasks and event responses, eye movements, and perceived workload and situational awareness were compared across different dual-task conditions. The results revealed that during dual-task walking, the reading app was associated with a significantly higher level of perceived workload, and impaired awareness of the surrounding environment to a greater extent compared with the texting or picture-dragging apps. Pedestrians took longer to visually detect the roadside events in the reading and texting conditions than in the dragging condition. Differences in event response performances were mainly dependent on their salient features but were also affected by the type of smartphone task. Texting was found to make participants more reliant on their central vision to detect road events. Moreover, different gaze-scanning patterns were adopted by participants to better protect dual-task performance in response to the changes in road-event frequency. The findings of relationships between workload, dual-task performances, and allocation strategies for visual attention further our understanding of pedestrian behavior and safety. By knowing how attentional and motor demands involved in different smartphone tasks affect pedestrians' awareness to critical roadside events, effective awareness campaigns might be devised to discourage smartphone use while walking. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effects of dual tasking on gait synchronization during over-ground side-by-side walking.

PubMed

Zivotofsky, Ari Z; Bernad-Elazari, Hagar; Grossman, Pnina; Hausdorff, Jeffrey M

2018-06-01

Recent studies have shown that gait synchronization during natural walking is not merely anecdotal, but it is a repeatable phenomenon that is quantifiable and is apparently related to available sensory feedback modalities. However, the mechanisms underlying this phase-locking of gait have only recently begun to be investigated. For example, it is not known what role, if any, attention plays. We employed a dual tasking paradigm in order to investigate the role attention plays in gait synchronization. Sixteen pairs of subjects walked under six conditions that manipulated the available sensory feedback and the degree of difficulty of the dual task, i.e., the attention. Movement was quantified using a trunk-mounted tri-axial accelerometer. A gait synchronization index (GSI) was calculated in order to quantify the degree of synchronization of the gait pattern. A simple dual task resulted in an increased level of synchronization, whereas a more complex dual task lead to a reduction in synchronization. Handholding increased synchronization, compared to the same attention condition without handholding. These results indicate that in order for two walkers to synchronize, some level of attention is apparently required, such that a relatively complex dual task utilizes enough attentional resources to reduce the occurrence of synchronization. Copyright © 2018 Elsevier B.V. All rights reserved.

Associations between physical function, dual-task performance and cognition in patients with mild Alzheimer's disease.

PubMed

Sobol, Nanna Aue; Hoffmann, Kristine; Vogel, Asmus; Lolk, Annette; Gottrup, Hanne; Høgh, Peter; Hasselbalch, Steen G; Beyer, Nina

2016-11-01

Alzheimer's disease (AD) causes a gradual decline in cognition, limitations of dual-tasking and physical function leading to total dependence. Hence, information about the interaction between physical function, dual-task performance and cognition may lead to new treatment strategies with the purpose of preserving function and quality of life. The objective of this study was to investigate the associations between physical function, dual-task performance and cognition in community-dwelling patients with mild AD. Baseline results from 185 participants (50-90 years old) in the single blinded multicenter RCT 'ADEX' (Alzheimer's disease: the effect of physical exercise) were used. Assessments included tests of physical function: 400-m walk test, 10-m walk test, Timed Up and Go test and 30-s chair stand test; dual-task performance, i.e., 10-m walk while counting backwards from 50 or naming the months backwards; and cognition, i.e., Mini Mental State Examination, Symbol Digit Modalities Test, the Stroop Color and Word Test, and Lexical verbal fluency test. Results in the 30-s chair stand test correlated significantly with all tests of cognition (r = .208-.242) while the other physical function tests only randomly correlated with tests of cognition. Results in the dual-task counting backwards correlated significantly with results in all tests of cognition (r = .259-.388), which accounted for 7%-15% of the variation indicating that a faster time to complete dual-task performance was associated with better cognitive performance. The evidence of the associations between physical function, dual-task performance and cognition is important when creating new rehabilitation interventions to patients with mild AD.

Walking stability during cell phone use in healthy adults.

PubMed

Kao, Pei-Chun; Higginson, Christopher I; Seymour, Kelly; Kamerdze, Morgan; Higginson, Jill S

2015-05-01

The number of falls and/or accidental injuries associated with cellular phone use during walking is growing rapidly. Understanding the effects of concurrent cell phone use on human gait may help develop safety guidelines for pedestrians. It was shown previously that older adults had more pronounced dual-task interferences than younger adults when concurrent cognitive task required visual information processing. Thus, cell phone use might have greater impact on walking stability in older than in younger adults. This study examined gait stability and variability during a cell phone dialing task (phone) and two classic cognitive tasks, the Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT). Nine older and seven younger healthy adults walked on a treadmill at four different conditions: walking only, PASAT, phone, and SDMT. We computed short-term local divergence exponent (LDE) of the trunk motion (local stability), dynamic margins of stability (MOS), step spatiotemporal measures, and kinematic variability. Older and younger adults had similar values of short-term LDE during all conditions, indicating that local stability was not affected by the dual-task. Compared to walking only, older and younger adults walked with significantly greater average mediolateral MOS during phone and SDMT conditions but significantly less ankle angle variability during all dual-tasks and less knee angle variability during PASAT. The current findings demonstrate that healthy adults may try to control foot placement and joint kinematics during cell phone use or another cognitive task with a visual component to ensure sufficient dynamic margins of stability and maintain local stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Walking Stability during Cell Phone Use in Healthy Adults

PubMed Central

Kao, Pei-Chun; Higginson, Christopher I.; Seymour, Kelly; Kamerdze, Morgan; Higginson, Jill S.

2015-01-01

The number of falls and/or accidental injuries associated with cellular phone use during walking is growing rapidly. Understanding the effects of concurrent cell phone use on human gait may help develop safety guidelines for pedestrians. It was shown previously that older adults had more pronounced dual-task interferences than younger adults when concurrent cognitive task required visual information processing. Thus, cell phone use might have greater impact on walking stability in older than in younger adults. This study examined gait stability and variability during a cell phone dialing task (phone) and two classic cognitive tasks, the Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT). Nine older and seven younger healthy adults walked on a treadmill at four different conditions: walking only, PASAT, phone, and SDMT. We computed short-term local divergence exponent (LDE) of the trunk motion (local stability), dynamic margins of stability (MOS), step spatiotemporal measures, and kinematic variability. Older and younger adults had similar values of short-term LDE during all conditions, indicating that local stability was not affected by the dual-task. Compared to walking only, older and younger adults walked with significantly greater average mediolateral MOS during phone and SDMT conditions but significantly less ankle angle variability during all dual-tasks and less knee angle variability during PASAT. The current findings demonstrate that healthy adults may try to control foot placement and joint kinematics during cell phone use or another cognitive task with a visual component to ensure sufficient dynamic margins of stability and maintain local stability. PMID:25890490

Are factors related to dual-task performance in people with Parkinson's disease dependent on the type of dual task?

PubMed

Strouwen, Carolien; Molenaar, Esther A L M; Keus, Samyra H J; Münks, Liesbeth; Heremans, Elke; Vandenberghe, Wim; Bloem, Bastiaan R; Nieuwboer, Alice

2016-02-01

Impaired dual-task performance significantly impacts upon functional mobility in people with Parkinson's disease (PD). The aim of this study was to identify determinants of dual-task performance in people with PD in three different dual tasks to assess their possible task-dependency. We recruited 121 home-dwelling patients with PD (mean age 65.93 years; mean disease duration 8.67 years) whom we subjected to regular walking (control condition) and to three dual-task conditions: walking combined with a backwards Digit Span task, an auditory Stroop task and a Mobile Phone task. We measured dual-task gait velocity using the GAITRite mat and dual-task reaction times and errors on the concurrent tasks as outcomes. Motor, cognitive and descriptive variables which correlated to dual-task performance (p < 0.20) were entered into a stepwise forward multiple linear regression model. Single-task gait velocity and executive function, tested by the alternating intake test, was significantly associated with gait velocity during the Digit Span (R(2) = 0.65; p < 0.001), the Stroop (R(2) = 0.73; p < 0.001) and the Mobile Phone task (R(2) = 0.62; p < 0.001). In addition, disease severity proved correlated to gait velocity during the Stroop task. Age was a surplus determinant of gait velocity while using a mobile phone. Single-task gait velocity and executive function as measured by a verbal fluency switching task were independent determinants of dual-task gait performance in people with PD. In contrast to expectation, these factors were the same across different tasks, supporting the robustness of the findings. Future study needs to determine whether these factors predict dual-task abnormalities prospectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Does the attentional demands of walking differ for older men and women living independently in the community?

PubMed

Wellmon, Robert

2012-01-01

Walking has been shown to be an attentionally demanding task. For older adults, gender-specific differences in gait and falling reported in the literature could arise as a result of the attentional demands of walking. However, differences in how older men and women allocate attention to walking have not been investigated. The purpose of this study was to use a dual-task voice reaction time paradigm to examine gender-specific differences in the attentional demands of walking in older adults who are independent in community ambulation. A dual-task paradigm was used to measure voice reaction time (VRT) in older community-dwelling men (n = 29; mean age = 78.40, SD = 6.17 years) and women (n = 33; mean age = 77.01, SD = 6.07 years) under 3 task conditions: sitting in a chair, standing, and walking on a level surface. Between- and within-group differences in dual-task VRT were examined using a 2 (men vs women) by 3 (task condition) repeated-measures analysis of variance. The level of statistical significance was set at 0.05, and a Bonferroni procedure was used for post hoc analyses. Sitting VRT was similar for men (mean = 454.90, SD = 140.05 milliseconds) and women (mean = 454.49, SD = 94.27 milliseconds). While standing, men had a slightly faster VRT (mean = 444.90, SD = 125.31 milliseconds vs mean = 452.09, SD = 92.82 milliseconds). When walking, VRT increased for both groups in comparison to sitting and standing and older men (mean = 509.11, SD = 142.19 milliseconds) responded faster than older women (mean = 537.55, SD = 122.43). However, the main effect of gender (P = .665) and interaction of gender with task (P = .433) were both not statistically significant. A statistically significant main effect for task (P < .001) indicated that walking VRT (mean = 524.25, SD = 131.71 milliseconds) was significantly longer than both sitting (P < .001, mean = 454.68, SD = 116.89 milliseconds) and standing (P < .001, mean = 448.36, SD = 108.37 milliseconds) VRT. The results demonstrate that the attentional demands of walking are not different for older adult men and women who are independent in community mobility. However, support was provided for the idea that walking is an attentionally demanding activity. In comparison with sitting and standing, walking was more attentionally demanding for both men and women. CONCLUSIONS.: A dual-task voice reaction time paradigm revealed that walking is not more attentionally demanding on the basis of gender when comparing community-dwelling older adult men with women.

Changes in Standing and Walking Performance Under Dual-Task Conditions Across the Lifespan.

PubMed

Ruffieux, Jan; Keller, Martin; Lauber, Benedikt; Taube, Wolfgang

2015-12-01

Simultaneous performance of a postural and a concurrent task is rather unproblematic as long as the postural task is executed in an automatic way. However, in situations where postural control requires more central processing, cognitive resources may be exceeded by the addition of an attentionally demanding task. This may lead to interference between the two tasks, manifested in a decreased performance in one or both tasks (dual-task costs). Owing to changes in attentional demands of postural tasks as well as processing capacities across the lifespan, it might be assumed that dual-task costs are particularly pronounced in children and older adults probably leading to a U-shaped pattern for dual-task costs as a function of age. However, these changes in the ability of dual-tasking posture from childhood to old age have not yet been systematically reviewed. Therefore, Web of Science and PubMed databases were searched for studies comparing dual-task performance with one task being standing or walking in healthy groups of young adults and either children or older adults. Seventy-nine studies met inclusion criteria. For older adults, the expected increase in dual-task costs could be confirmed. In contrast, in children there was only feeble evidence for a trend towards enlarged dual-task costs. More good-quality studies comparing dual-task ability in children, young, and, ideally, also older adults within the same paradigm are needed to draw unambiguous conclusions about lifespan development of dual-task performance in postural tasks. There is evidence that, in older adults, dual-task performance can be improved by training. For the other age groups, these effects have yet to be investigated.

Walking execution is not affected by divided attention in patients with multiple sclerosis with no disability, but there is a motor planning impairment.

PubMed

Nogueira, Leandro Alberto Calazans; Santos, Luciano Teixeira Dos; Sabino, Pollyane Galinari; Alvarenga, Regina Maria Papais; Thuler, Luiz Claudio Santos

2013-08-01

We analysed the cognitive influence on walking in multiple sclerosis (MS) patients, in the absence of clinical disability. A case-control study was conducted with 12 MS patients with no disability and 12 matched healthy controls. Subjects were referred for completion a timed walk test of 10 m and a 3D-kinematic analysis. Participants were instructed to walk at a comfortable speed in a dual-task (arithmetic task) condition, and motor planning was measured by mental chronometry. Scores of walking speed and cadence showed no statistically significant differences between the groups in the three conditions. The dual-task condition showed an increase in the double support duration in both groups. Motor imagery analysis showed statistically significant differences between real and imagined walking in patients. MS patients with no disability did not show any influence of divided attention on walking execution. However, motor planning was overestimated as compared with real walking.

Measuring prefrontal cortical activity during dual task walking in patients with Parkinson's disease: feasibility of using a new portable fNIRS device.

PubMed

Nieuwhof, Freek; Reelick, Miriam F; Maidan, Inbal; Mirelman, Anat; Hausdorff, Jeffrey M; Olde Rikkert, Marcel G M; Bloem, Bastiaan R; Muthalib, Makii; Claassen, Jurgen A H R

2016-01-01

Many patients with Parkinson's disease (PD) have difficulties in performing a second task during walking (i.e., dual task walking). Functional near-infrared spectroscopy (fNIRS) is a promising approach to study the presumed contribution of dysfunction within the prefrontal cortex (PFC) to such difficulties. In this pilot study, we examined the feasibility of using a new portable and wireless fNIRS device to measure PFC activity during different dual task walking protocols in PD. Specifically, we tested whether PD patients were able to perform the protocol and whether we were able to measure the typical fNIRS signal of neuronal activity. We included 14 PD patients (age 71.2 ± 5.4 years, Hoehn and Yahr stage II/III). The protocol consisted of five repetitions of three conditions: walking while (i) counting forwards, (ii) serially subtracting, and (iii) reciting digit spans. Ability to complete this protocol, perceived exertion, burden of the fNIRS devices, and concentrations of oxygenated (O 2 Hb) and deoxygenated (HHb) hemoglobin from the left and right PFC were measured. Two participants were unable to complete the protocol due to fatigue and mobility safety concerns. The remaining 12 participants experienced no burden from the two fNIRS devices and completed the protocol with ease. Bilateral PFC O 2 Hb concentrations increased during walking while serially subtracting (left PFC 0.46 μmol/L, 95 % confidence interval (CI) 0.12-0.81, right PFC 0.49 μmol/L, 95 % CI 0.14-0.84) and reciting digit spans (left PFC 0.36 μmol/L, 95 % CI 0.03-0.70, right PFC 0.44 μmol/L, 95 % CI 0.09-0.78) when compared to rest. HHb concentrations did not differ between the walking tasks and rest. These findings suggest that a new wireless fNIRS device is a feasible measure of PFC activity in PD during dual task walking. Future studies should reduce the level of noise and inter-individual variability to enable measuring differences in PFC activity between different dual walking conditions and across health states.

Protocol for a randomized comparison of integrated versus consecutive dual task practice in Parkinson’s disease: the DUALITY trial

PubMed Central

2014-01-01

Background Multiple tasking is an integral part of daily mobility. Patients with Parkinson’s disease have dual tasking difficulties due to their combined motor and cognitive deficits. Two contrasting physiotherapy interventions have been proposed to alleviate dual tasking difficulties: either to discourage simultaneous execution of dual tasks (consecutive training); or to practice their concurrent use (integrated training). It is currently unclear which of these training methods should be adopted to achieve safe and consolidated dual task performance in daily life. Therefore, the proposed randomized controlled trial will compare the effects of integrated versus consecutive training of dual tasking (tested by combining walking with cognitive exercises). Methods and design Hundred and twenty patients with Parkinson’s disease will be recruited to participate in this multi-centered, single blind, randomized controlled trial. Patients in Hoehn & Yahr stage II-III, with or without freezing of gait, and who report dual task difficulties will be included. All patients will undergo a six-week control period without intervention after which they will be randomized to integrated or consecutive task practice. Training will consist of standardized walking and cognitive exercises delivered at home four times a week during six weeks. Treatment is guided by a physiotherapist twice a week and consists of two sessions of self-practice using an MP3 player. Blinded testers will assess patients before and after the control period, after the intervention period and after a 12-week follow-up period. The primary outcome measure is dual task gait velocity, i.e. walking combined with a novel untrained cognitive task to evaluate the consolidation of learning. Secondary outcomes include several single and dual task gait and cognitive measures, functional outcomes and a quality of life scale. Falling will be recorded as a possible adverse event using a weekly phone call for the entire study period. Discussion This randomized study will evaluate the effectiveness and safety of integrated versus consecutive task training in patients with Parkinson’s disease. The study will also highlight whether dual task gait training leads to robust motor learning effects, and whether these can be retained and carried-over to untrained dual tasks and functional mobility. Trial registration Clinicaltrials.gov NCT01375413. PMID:24674594

The effect of dual tasking on foot kinematics in people with functional ankle instability.

PubMed

Tavakoli, Sanam; Forghany, Saeed; Nester, Christopher

2016-09-01

Some cases of repeated inversion ankle sprains are thought to have a neurological basis and are termed functional ankle instability (FAI). In addition to factors local to the ankle, such as loss of proprioception, cognitive demands have the ability to influence motor control and may increase the risk of repetitive lateral sprains. The purpose of this study was to investigate the effect of cognitive demand on foot kinematics in physically active people with functional ankle instability. 21 physically active participants with FAI and 19 matched healthy controls completed trials of normal walking (single task) and normal walking while performing a cognitive task (dual task). Foot motion relative to the shank was recorded. Cognitive performance, ankle kinematics and movement variability in single and dual task conditions was characterized. During normal walking, the ankle joint was significantly more inverted in FAI compared to the control group pre and post initial contact. Under dual task conditions, there was a statistically significant increase in frontal plane foot movement variability during the period 200ms pre and post initial contact in people with FAI compared to the control group (p<0.05). Dual task also significantly increased plantar flexion and inversion during the period 200ms pre and post initial contact in the FAI group (p<0.05). participants with FAI demonstrated different ankle movement patterns and increased movement variability during a dual task condition. Cognitive load may increase risk of ankle instability in these people. Copyright © 2016 Elsevier B.V. All rights reserved.

Changes in gait while backward counting in demented older adults with frontal lobe dysfunction.

PubMed

Allali, Gilles; Kressig, Reto W; Assal, Frédéric; Herrmann, François R; Dubost, Véronique; Beauchet, Olivier

2007-10-01

Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-tasking is used to explore the involvement of cortical level in gait control. It has been shown that dual-task induced gait changes that could be related to (1) the efficiency of executive function, (2) the level of difficulty involved in the walking-associated task, or (3) the articulo-motor components comprised in the walking-associated task. A better understanding of dual-task related changes in demented subjects with frontal lobe dysfunction could help us to clarify the role of the frontal lobe in motor gait control. To assess and compare the effects of two mental arithmetic tasks involving similar articulo-motor components but different level of difficulty on the mean values and coefficient of variation (CV) of stride time among demented older adults with impaired executive function. The mean values and coefficients of variation of stride time were measured using a GAITRite-System among 16 demented older adults with impaired executive function while walking with and without forward counting (FC) and backward counting (BC). The mean values and CV of stride time were significantly higher under both dual-task conditions than during a simple walking task (p<0.05). The change in CV of stride time during BC was significantly higher when compared with the change during FC (p=0.015), whereas the change in mean value was not significant (p=0.056). There was no difference between the dual-task and single task condition as far the number of enumerated figures were concerned (p=0.678 for FC and p=0.069 for BC), but significantly fewer figures were enumerated while BC compared with FC (p<0.001). BC provoked more changes in gait parameters than FC with major modification in gait variability related to an inappropriate focusing of attention. These findings suggest that the CV may be a suitable criterion for the assessment of gait control.

Model task for the dynamics of an underwater two-legged walker

NASA Technical Reports Server (NTRS)

Beletskiy, V. V.; Golubkov, V. V.; Stepanova, Y. A.

1979-01-01

A model task of two-legged underwater walking was examined. Characteristics of the walking were established. The underwater walking device is a substantial sphere, which moves on dual-member legs. The dynamics of the device were investigated with the calculation of the buoyancy of Archimedes, and the force of hydrodynamic resistance.

Does Combined Physical and Cognitive Training Improve Dual-Task Balance and Gait Outcomes in Sedentary Older Adults?

PubMed Central

Fraser, Sarah A.; Li, Karen Z.-H.; Berryman, Nicolas; Desjardins-Crépeau, Laurence; Lussier, Maxime; Vadaga, Kiran; Lehr, Lora; Minh Vu, Thien Tuong; Bosquet, Laurent; Bherer, Louis

2017-01-01

Everyday activities like walking and talking can put an older adult at risk for a fall if they have difficulty dividing their attention between motor and cognitive tasks. Training studies have demonstrated that both cognitive and physical training regimens can improve motor and cognitive task performance. Few studies have examined the benefits of combined training (cognitive and physical) and whether or not this type of combined training would transfer to walking or balancing dual-tasks. This study examines the dual-task benefits of combined training in a sample of sedentary older adults. Seventy-two older adults (≥60 years) were randomly assigned to one of four training groups: Aerobic + Cognitive training (CT), Aerobic + Computer lessons (CL), Stretch + CT and Stretch + CL. It was expected that the Aerobic + CT group would demonstrate the largest benefits and that the active placebo control (Stretch + CL) would show the least benefits after training. Walking and standing balance were paired with an auditory n-back with two levels of difficulty (0- and 1-back). Dual-task walking and balance were assessed with: walk speed (m/s), cognitive accuracy (% correct) and several mediolateral sway measures for pre- to post-test improvements. All groups demonstrated improvements in walk speed from pre- (M = 1.33 m/s) to post-test (M = 1.42 m/s, p < 0.001) and in accuracy from pre- (M = 97.57%) to post-test (M = 98.57%, p = 0.005).They also increased their walk speed in the more difficult 1-back (M = 1.38 m/s) in comparison to the 0-back (M = 1.36 m/s, p < 0.001) but reduced their accuracy in the 1-back (M = 96.39%) in comparison to the 0-back (M = 99.92%, p < 0.001). Three out of the five mediolateral sway variables (Peak, SD, RMS) demonstrated significant reductions in sway from pre to post test (p-values < 0.05). With the exception of a group difference between Aerobic + CT and Stretch + CT in accuracy, there were no significant group differences after training. Results suggest that there can be dual-task benefits from training but that in this sedentary sample Aerobic + CT training was not more beneficial than other types of combined training. PMID:28149274

Musical dual-task training in patients with mild-to-moderate dementia: a randomized controlled trial.

PubMed

Chen, Yu-Ling; Pei, Yu-Cheng

2018-01-01

Dual-task training may improve dual-task gait performance, balance, and cognition in older adults with and without cognitive impairment. Although music has been widely utilized in dementia management, there are no existing protocols for music-based dual-task training. This randomized controlled study developed a Musical Dual-Task Training (MDTT) protocol that patients with dementia can use to practice walking and making music simultaneously, to enhance attention control in patients during dual-tasking. Twenty-eight adults diagnosed with mild-to-moderate dementia were assigned to the MDTT (n=15) or control groups (n=13). The MDTT group received MDTT, while the control group participated in non-musical cognitive and walking activities. The effects of MDTT were evaluated through the primary outcome of attention control, and secondary outcomes of dual-task performance, balance, falls efficacy, and agitation. The MDTT group showed a significant improvement in attention control, while the control group did not ( P <0.001). A significant effect favored MDTT over control treatment for the secondary outcome of falls efficacy ( P =0.02) and agitation ( P <0.01). MDTT, a music therapy intervention that demands a high level of cognitive processing, enhances attention control, falls efficacy, and helps alleviate agitation in patients with mild-to-moderate dementia.

Musical dual-task training in patients with mild-to-moderate dementia: a randomized controlled trial

PubMed Central

Chen, Yu-Ling; Pei, Yu-Cheng

2018-01-01

Background/aims Dual-task training may improve dual-task gait performance, balance, and cognition in older adults with and without cognitive impairment. Although music has been widely utilized in dementia management, there are no existing protocols for music-based dual-task training. This randomized controlled study developed a Musical Dual-Task Training (MDTT) protocol that patients with dementia can use to practice walking and making music simultaneously, to enhance attention control in patients during dual-tasking. Methods Twenty-eight adults diagnosed with mild-to-moderate dementia were assigned to the MDTT (n=15) or control groups (n=13). The MDTT group received MDTT, while the control group participated in non-musical cognitive and walking activities. The effects of MDTT were evaluated through the primary outcome of attention control, and secondary outcomes of dual-task performance, balance, falls efficacy, and agitation. Results The MDTT group showed a significant improvement in attention control, while the control group did not (P<0.001). A significant effect favored MDTT over control treatment for the secondary outcome of falls efficacy (P=0.02) and agitation (P<0.01). Conclusion MDTT, a music therapy intervention that demands a high level of cognitive processing, enhances attention control, falls efficacy, and helps alleviate agitation in patients with mild-to-moderate dementia. PMID:29881275

[Trail walking test for assessment of motor cognitive interference in older adults. Development and evaluation of the psychometric properties of the procedure].

PubMed

Schott, Nadja

2015-12-01

Activities of daily living (ADL), such as walking, often involve the added complexity of walking while doing other activities (i.e. dual task walking). A complex walking task may require a greater motor and mental capacity, resulting in decrements in gait performance not seen for simple walking tasks. The purpose of this study was to determine if the trail walking test (TWT), the mobile adaptation of the trail making test (TMT), could be a reliable and valid early detection tool to discriminate between non-fallers and fallers. This study examined dual task costs of a cognitive and a sensorimotor task (walking) in 94 older adults aged 50-81 years (average age M = 67.4 years, SD ± 7.34). Based on the idea of the paper and pencil TMT, participants walked along a fixed pathway (TWT-1), stepped on targets with increasing sequential numbers (i.e. 1, 2, 3, TWT-2), and increasing sequential numbers and letters (i.e. 1, A, 2, B, 3, C, TWT-3). The dual task costs were calculated for each task. Additionally, the following tests were conducted: TMT, block tapping test (BTT), timed up and go (TUG) test, 30s chair rising test, 10 m walking time test with and without head turns, German physical activity questionnaire (German PAQ-50 +) and the activities-specific balance confidence (ABC-D) scale. The TWT performance times as well as errors increased with increasing age. Reliability coefficients were high (interclass correlation ICC > 0.90). Correlations between the different TWT conditions and potential falls-related predictors were moderate to high (r = -0.430 to 0.699). Of the participants 34 % reported falling in the past year. The stepwise logistic regression analysis revealed that the dual task costs for the numbers and letters (odds ratio OR 1.162, 95 % confidence interval CI 1.058-1.277, p = 0.002), the ABC-D (OR 0.767, 95 % CI 0.651-0.904, p = 0.002) and exercise (OR 1.027, 95 % CI 1.008-1.046, p = 0.006) were significantly related to falls and 91.6 % of cases were correctly classified. The results indicate that high-level cognitive processes interfere with automatic processes such as walking. The TWT which converts a relevant fall risk-associated standard neuropsychological test (TMT) with increasing cognitive load into a mobility task, was shown to be a feasible, reliable and valid tool for older adults to discriminate between non-fallers and fallers.

Effects of dual-task balance training on postural performance in patients with Multiple Sclerosis: a double-blind, randomized controlled pilot trial.

PubMed

Monjezi, Saeideh; Negahban, Hossein; Tajali, Shirin; Yadollahpour, Nava; Majdinasab, Nastaran

2017-02-01

To investigate the effects of dual-task balance training on postural performance in patients with multiple sclerosis as compared with single-task balance training. Double-blind, pretest-posttest, randomized controlled pilot trial. Local Multiple Sclerosis Society. A total of 47 patients were randomly assigned to two equal groups labeled as single-task training and dual-task training groups. All patients received supervised balance training sessions, 3 times per week for 4 weeks. The patients in the single-task group performed balance activities, alone. However, patients in dual-task group practiced balance activities while simultaneously performing cognitive tasks. The 10-Meter Walk Test and Timed Up-and-Go under single-task and dual-task conditions, in addition to Activities-specific Balance Confidence, Berg Balance Scale, and Functional Gait Assessment were assessed pre-, and post intervention and also 6-weeks after the end of intervention. Only 38 patients completed the treatment plan. There was no difference in the amount of improvement seen between the two study groups. In both groups there was a significant effect of time for dual-10 Meter Walk Test (F 1, 36 =11.33, p=0.002) and dual-Timed Up-and-Go (F 1, 36 =14.27, p=0.001) but not for their single-tasks. Moreover, there was a significant effect of time for Activities-specific Balance Confidence, Berg Balance Scale, and Functional Gait Assessment ( P<0.01). This pilot study did not show more benefits from undertaking dual-task training than single-task training. A power analysis showed 71 patients per group would be needed to determine whether there was a clinically relevant difference for dual-task gait speed between the groups.

Effect of the cognitive-motor dual-task using auditory cue on balance of surviviors with chronic stroke: a pilot study.

PubMed

Choi, Wonjae; Lee, GyuChang; Lee, Seungwon

2015-08-01

To investigate the effect of a cognitive-motor dual-task using auditory cues on the balance of patients with chronic stroke. Randomized controlled trial. Inpatient rehabilitation center. Thirty-seven individuals with chronic stroke. The participants were randomly allocated to the dual-task group (n=19) and the single-task group (n=18). The dual-task group performed a cognitive-motor dual-task in which they carried a circular ring from side to side according to a random auditory cue during treadmill walking. The single-task group walked on a treadmill only. All subjects completed 15 min per session, three times per week, for four weeks with conventional rehabilitation five times per week over the four weeks. Before and after intervention, both static and dynamic balance were measured with a force platform and using the Timed Up and Go (TUG) test. The dual-task group showed significant improvement in all variables compared to the single-task group, except for anteroposterior (AP) sway velocity with eyes open and TUG at follow-up: mediolateral (ML) sway velocity with eye open (dual-task group vs. single-task group: 2.11 mm/s vs. 0.38 mm/s), ML sway velocity with eye close (2.91 mm/s vs. 1.35 mm/s), AP sway velocity with eye close (4.84 mm/s vs. 3.12 mm/s). After intervention, all variables showed significant improvement in the dual-task group compared to baseline. The study results suggest that the performance of a cognitive-motor dual-task using auditory cues may influence balance improvements in chronic stroke patients. © The Author(s) 2014.

The interacting effect of cognitive and motor task demands on performance of gait, balance and cognition in young adults.

PubMed

Szturm, Tony; Maharjan, Pramila; Marotta, Jonathan J; Shay, Barbara; Shrestha, Shiva; Sakhalkar, Vedant

2013-09-01

Mobility limitations and cognitive impairments, each common with aging, reduce levels of physical and mental activity, are prognostic of future adverse health events, and are associated with an increased fall risk. The purpose of this study was to examine whether divided attention during walking at a constant speed would decrease locomotor rhythm, stability, and cognitive performance. Young healthy participants (n=20) performed a visuo-spatial cognitive task in sitting and while treadmill walking at 2 speeds (0.7 and 1.0 m/s).Treadmill speed had a significant effect on temporal gait variables and ML-COP excursion. Cognitive load did not have a significant effect on average temporal gait variables or COP excursion, but variation of gait variables increased during dual-task walking. ML and AP trunk motion was found to decrease during dual-task walking. There was a significant decrease in cognitive performance (success rate, response time and movement time) while walking, but no effect due to treadmill speed. In conclusion walking speed is an important variable to be controlled in studies that are designed to examine effects of concurrent cognitive tasks on locomotor rhythm, pacing and stability. Divided attention during walking at a constant speed did result in decreased performance of a visuo-spatial cognitive task and an increased variability in locomotor rhythm. Copyright © 2013 Elsevier B.V. All rights reserved.

Observing prioritization effects on cognition and gait: The effect of increased cognitive load on cognitively healthy older adults' dual-task performance.

PubMed

Maclean, Linda M; Brown, Laura J E; Khadra, H; Astell, Arlene J

2017-03-01

Previous studies exploring the effects of attention-prioritization on cognitively healthy older adults' gait and cognitive dual task (DT) performance have shown DT cost in gait outcomes but inconsistent effects on cognitive performance, which may reflect task difficulty (the cognitive load). This study aimed to identify whether changing the cognitive load during a walking and counting DT improved the challenge/sensitivity of the cognitive task to observe prioritization effects on concurrent gait and cognitive performance outcomes. Seventy-two cognitively healthy older adults (Mean=73years) walked 15m, counted backwards in 3s and 7s as single tasks (ST), and concurrently walked and counted backwards as DTs. Attention-prioritization was examined in Prioritizing Walking (PW) and Prioritizing Counting (PC) DT conditions. Dual-task performance costs (DTC) were calculated for number of correct cognitive responses (CCR) in the counting tasks, and step-time variability and velocity in the gait task. All DT conditions showed a benefit (DTB) for cognitive outcomes with trade-off cost to gait. In the Serial 3s task, the cognitive DTBs increased in PC over the PW condition (p<0.05), with a greater cost to walking velocity (p<0.05). DT effects were more pronounced in the Serial 7s with a lower cognitive DTB when PC than when PW, (p<0.05) with no trade-off increase in cost to gait outcomes (p<0.05). The findings suggest that increased cognitive load during a gait and cognitive DT produces more pronounced gait measures of attention-prioritization in cognitively healthy older adults. A cognitive load effect was also observed in the cognitive outcomes, with unexpected results. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Backpack Carriage on Dual-Task Performance in Children During Standing and Walking.

PubMed

Beurskens, Rainer; Muehlbauer, Thomas; Grabow, Lena; Kliegl, Reinhold; Granacher, Urs

2016-01-01

Primary school children perform parts of their everyday activities while carrying school supplies and being involved in attention-demanding situations. Twenty-eight children (8-10 years old) performed a 1-legged stance and a 10 m walking test under single- and dual-task situations in unloaded (i.e., no backpack) and loaded conditions (i.e., backpack with 20% of body mass). Results showed that load carriage did not significantly influence children's standing and walking performance (all p > .05), while divided attention affected all proxies of walking (all p < .001). Last, no significant load by attention interactions was detected. The single application of attentional but not load demand negatively affects children's walking performance. A combined application of both did not further deteriorate their gait behavior.

Effects of Hearing Loss on Dual-Task Performance in an Audiovisual Virtual Reality Simulation of Listening While Walking.

PubMed

Lau, Sin Tung; Pichora-Fuller, M Kathleen; Li, Karen Z H; Singh, Gurjit; Campos, Jennifer L

2016-07-01

Most activities of daily living require the dynamic integration of sights, sounds, and movements as people navigate complex environments. Nevertheless, little is known about the effects of hearing loss (HL) or hearing aid (HA) use on listening during multitasking challenges. The objective of the current study was to investigate the effect of age-related hearing loss (ARHL) on word recognition accuracy in a dual-task experiment. Virtual reality (VR) technologies in a specialized laboratory (Challenging Environment Assessment Laboratory) were used to produce a controlled and safe simulated environment for listening while walking. In a simulation of a downtown street intersection, participants completed two single-task conditions, listening-only (standing stationary) and walking-only (walking on a treadmill to cross the simulated intersection with no speech presented), and a dual-task condition (listening while walking). For the listening task, they were required to recognize words spoken by a target talker when there was a competing talker. For some blocks of trials, the target talker was always located at 0° azimuth (100% probability condition); for other blocks, the target talker was more likely (60% of trials) to be located at the center (0° azimuth) and less likely (40% of trials) to be located at the left (270° azimuth). The participants were eight older adults with bilateral HL (mean age = 73.3 yr, standard deviation [SD] = 8.4; three males) who wore their own HAs during testing and eight controls with normal hearing (NH) thresholds (mean age = 69.9 yr, SD = 5.4; two males). No participant had clinically significant visual, cognitive, or mobility impairments. Word recognition accuracy and kinematic parameters (head and trunk angles, step width and length, stride time, cadence) were analyzed using mixed factorial analysis of variances with group as a between-subjects factor. Task condition (single versus dual) and probability (100% versus 60%) were within-subject factors. In analyses of the 60% listening condition, spatial expectation (likely versus unlikely) was a within-subject factor. Differences between groups in age and baseline measures of hearing, mobility, and cognition were tested using t tests. The NH group had significantly better word recognition accuracy than the HL group. Both groups performed better when the probability was higher and the target location more likely. For word recognition, dual-task costs for the HL group did not depend on condition, whereas the NH group demonstrated a surprising dual-task benefit in conditions with lower probability or spatial expectation. For the kinematic parameters, both groups demonstrated a more upright and less variable head position and more variable trunk position during dual-task conditions compared to the walking-only condition, suggesting that safe walking was prioritized. The HL group demonstrated more overall stride time variability than the NH group. This study provides new knowledge about the effects of ARHL, HA use, and aging on word recognition when individuals also perform a mobility-related task that is typically experienced in everyday life. This research may help inform the development of more effective function-based approaches to assessment and intervention for people who are hard-of-hearing. American Academy of Audiology.

[Assessing Motor-Cognition Interaction of Patients with Cognitive Disorders: Clinical Aspects].

PubMed

Schniepp, R; Wuehr, M; Schöberl, F; Zwergal, A

2016-08-01

Difficulties of walking and deficits of cognitive functions appear to be associated in the elderly. Thus, clinical assessment in geriatry and neurology should focus on: (1) diagnostic approaches covering both domains of everyday functioning; (2) therapeutic interventions that take into account possible interactions and synergies of both domains. In order to assess the capability for motor-cognitive interactions in the elderly it is recommended to investigate walking patterns during dual-tasks (e.g. walking and counting backwards, walking and naming words) and to examine clinical tests of everyday mobility tasks, such as the Timed-up-and-go-Test and spatial navigation tasks. Patients with cognitive disorders often perform inferior with a reduction of walking speed and an increase of stepping variability. Dual-task performance appears to be a reliable parameter for long-term observations of the course of the disease. Moreover, it might improve the quality of the gait examination during diagnostic or therapeutic interventions (e.g. the spinal tap test in patients with NPH). Several studies further highlight gait deficits during dual-task walking as a marker for the everyday functioning and the quality of life in elderly persons and patients with cognitive disorders.Therapeutic approaches in this context comprise complex motor-cognitive interventions, such as Thai Chi and Dalcroze rhythmic exercises. These interventions appear to act synergistically in motor and cognitive domains. First evidence for the efficacy for improving executive functions and reducing the fall risk of patients with cognitive impairments is given, thought randomized, controlled trials are rare. © Georg Thieme Verlag KG Stuttgart · New York.

Gait disorders in the elderly and dual task gait analysis: a new approach for identifying motor phenotypes.

PubMed

Auvinet, Bernard; Touzard, Claude; Montestruc, François; Delafond, Arnaud; Goeb, Vincent

2017-01-31

Gait disorders and gait analysis under single and dual-task conditions are topics of great interest, but very few studies have looked for the relevance of gait analysis under dual-task conditions in elderly people on the basis of a clinical approach. An observational study including 103 patients (mean age 76.3 ± 7.2, women 56%) suffering from gait disorders or memory impairment was conducted. Gait analysis under dual-task conditions was carried out for all patients. Brain MRI was performed in the absence of contra-indications. Three main gait variables were measured: walking speed, stride frequency, and stride regularity. For each gait variable, the dual task cost was computed and a quartile analysis was obtained. Nonparametric tests were used for all the comparisons (Wilcoxon, Kruskal-Wallis, Fisher or Chi 2 tests). Four clinical subgroups were identified: gait instability (45%), recurrent falls (29%), memory impairment (18%), and cautious gait (8%). The biomechanical severity of these subgroups was ordered according to walking speed and stride regularity under both conditions, from least to most serious as follows: memory impairment, gait instability, recurrent falls, cautious gait (p < 0.01 for walking speed, p = 0.05 for stride regularity). According to the established diagnoses of gait disorders, 5 main pathological subgroups were identified (musculoskeletal diseases (n = 11), vestibular diseases (n = 6), mild cognitive impairment (n = 24), central nervous system pathologies, (n = 51), and without diagnosis (n = 8)). The dual task cost for walking speed, stride frequency and stride regularity were different among these subgroups (p < 0.01). The subgroups mild cognitive impairment and central nervous system pathologies both showed together a higher dual task cost for each variable compared to the other subgroups combined (p = 0.01). The quartile analysis of dual task cost for stride frequency and stride regularity allowed the identification of 3 motor phenotypes (p < 0.01), without any difference for white matter hyperintensities, but with an increased Scheltens score from the first to the third motor phenotype (p = 0.05). Gait analysis under dual-task conditions in elderly people suffering from gait disorders or memory impairment is of great value in assessing the severity of gait disorders, differentiating between peripheral pathologies and central nervous system pathologies, and identifying motor phenotypes. Correlations between motor phenotypes and brain imaging require further studies.

A dual-learning paradigm can simultaneously train multiple characteristics of walking

PubMed Central

Toliver, Alexis; Bastian, Amy J.

2016-01-01

Impairments in human motor patterns are complex: what is often observed as a single global deficit (e.g., limping when walking) is actually the sum of several distinct abnormalities. Motor adaptation can be useful to teach patients more normal motor patterns, yet conventional training paradigms focus on individual features of a movement, leaving others unaddressed. It is known that under certain conditions, distinct movement components can be simultaneously adapted without interference. These previous “dual-learning” studies focused solely on short, planar reaching movements, yet it is unknown whether these findings can generalize to a more complex behavior like walking. Here we asked whether a dual-learning paradigm, incorporating two distinct motor adaptation tasks, can be used to simultaneously train multiple components of the walking pattern. We developed a joint-angle learning task that provided biased visual feedback of sagittal joint angles to increase peak knee or hip flexion during the swing phase of walking. Healthy, young participants performed this task independently or concurrently with another locomotor adaptation task, split-belt treadmill adaptation, where subjects adapted their step length symmetry. We found that participants were able to successfully adapt both components of the walking pattern simultaneously, without interference, and at the same rate as adapting either component independently. This leads us to the interesting possibility that combining rehabilitation modalities within a single training session could be used to help alleviate multiple deficits at once in patients with complex gait impairments. PMID:26961100

A training program to improve gait while dual tasking in patients with Parkinson's disease: a pilot study.

PubMed

Yogev-Seligmann, Galit; Giladi, Nir; Brozgol, Marina; Hausdorff, Jeffrey M

2012-01-01

Impairments in the ability to perform another task while walking (ie, dual tasking [DT]) are associated with an increased risk of falling. Here we describe a program we developed specifically to improve DT performance while walking based on motor learning principles and task-specific training. We examined feasibility, potential efficacy, retention, and transfer to the performance of untrained tasks in a pilot study among 7 patients with Parkinson's disease (PD). Seven patients (Hoehn and Yahr stage, 2.1±0.2) were evaluated before, after, and 1 month after 4 weeks of DT training. Gait speed and gait variability were measured during usual walking and during 4 DT conditions. The 4-week program of one-on-one training included walking while performing several distinct cognitive tasks. Gait speed and gait variability during DT significantly improved. Improvements were also seen in the DT conditions that were not specifically trained and were retained 1 month after training. These initial findings support the feasibility of applying a task-specific DT gait training program for patients with PD and suggest that it positively affects DT gait, even in untrained tasks. The present results are also consistent with the possibility that DT gait training enhances divided attention abilities during walking. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Effects of aging on the relationship between cognitive demand and step variability during dual-task walking.

PubMed

Decker, Leslie M; Cignetti, Fabien; Hunt, Nathaniel; Potter, Jane F; Stergiou, Nicholas; Studenski, Stephanie A

2016-08-01

A U-shaped relationship between cognitive demand and gait control may exist in dual-task situations, reflecting opposing effects of external focus of attention and attentional resource competition. The purpose of the study was twofold: to examine whether gait control, as evaluated from step-to-step variability, is related to cognitive task difficulty in a U-shaped manner and to determine whether age modifies this relationship. Young and older adults walked on a treadmill without attentional requirement and while performing a dichotic listening task under three attention conditions: non-forced (NF), forced-right (FR), and forced-left (FL). The conditions increased in their attentional demand and requirement for inhibitory control. Gait control was evaluated by the variability of step parameters related to balance control (step width) and rhythmic stepping pattern (step length and step time). A U-shaped relationship was found for step width variability in both young and older adults and for step time variability in older adults only. Cognitive performance during dual tasking was maintained in both young and older adults. The U-shaped relationship, which presumably results from a trade-off between an external focus of attention and competition for attentional resources, implies that higher-level cognitive processes are involved in walking in young and older adults. Specifically, while these processes are initially involved only in the control of (lateral) balance during gait, they become necessary for the control of (fore-aft) rhythmic stepping pattern in older adults, suggesting that attentional resources turn out to be needed in all facets of walking with aging. Finally, despite the cognitive resources required by walking, both young and older adults spontaneously adopted a "posture second" strategy, prioritizing the cognitive task over the gait task.

Entorhinal Cortex Volume Is Associated With Dual-Task Gait Cost Among Older Adults With MCI: Results From the Gait and Brain Study.

PubMed

Sakurai, Ryota; Bartha, Robert; Montero-Odasso, Manuel

2018-05-15

Low dual-task gait performance (the slowing of gait speed while performing a demanding cognitive task) is associated with low cognitive performance and an increased risk of progression to dementia in older adults with mild cognitive impairment. However, the reason for this remains unclear. This study aimed to examine the relationship between dual-task cost and regional brain volume, focusing on the hippocampus, parahippocampal gyrus, entorhinal cortex, and motor and lateral frontal cortices in older adults with mild cognitive impairment. Forty older adults with mild cognitive impairment from the "Gait and Brain Study" were included in this study. Gait velocity was measured during single-task (ie, walking alone) and dual-task (ie, counting backwards, subtracting serial sevens, and naming animals, in addition to walking) conditions, using an electronic walkway. Regional brain volumes were derived by automated segmentation, using 3T magnetic resonance imaging. Partial rank correlation analyses demonstrated that a smaller volume of the left entorhinal cortex was associated with higher dual-task costs in counting backwards and subtracting serial sevens conditions. Subsequent logistic regression analyses demonstrated that a smaller volume of the left entorhinal cortex was independently associated with higher dual-task cost (slowing down >20% when performing cognitive task) in these two conditions. There were no other significant associations. Our results show that lower dual-task gait performance is associated with volume reduction in the entorhinal cortex. Cognitive and motor dysfunction in older adults with mild cognitive impairment may reflect a shared pathogenic mechanism, and dual-task-related gait changes might be a surrogate motor marker for Alzheimer's disease pathology.

Empirical Support for 'Hastening-Through-Re-Automatization' by Contrasting Two Motor-Cognitive Dual Tasks.

PubMed

Langhanns, Christine; Müller, Hermann

2018-01-01

Motor-cognitive dual tasks have been intensely studied and it has been demonstrated that even well practiced movements like walking show signs of interference when performed concurrently with a challenging cognitive task. Typically walking speed is reduced, at least in elderly persons. In contrast to these findings, some authors report an increased movement frequency under dual-task conditions, which they call hastening . A tentative explanation has been proposed, assuming that the respective movements are governed by an automatic control regime. Though, under single-task conditions, these automatic processes are supervised by "higher-order" cognitive control processes. However, when a concurrent cognitive task binds all cognitive resources, the automatic process is freed from the detrimental effect of cognitive surveillance, allowing higher movement frequencies. Fast rhythmic movements (>1 Hz) should more likely be governed by such an automatic process than low frequency discrete repetitive movements. Fifteen subjects performed two repetitive movements under single and dual-task condition, that is, in combination with a mental calculation task. According to the expectations derived from the explanatory concept, we found an increased movement frequency under dual-task conditions only for the fast rhythmic movement (paddleball task) but not for the slower discrete repetitive task (pegboard task). fNIRS measurements of prefrontal cortical load confirmed the idea of an automatic processing in the paddleball task, whereas the pegboard task seems to be more controlled by processes interfering with the calculation related processing.

Empirical Support for ‘Hastening-Through-Re-Automatization’ by Contrasting Two Motor-Cognitive Dual Tasks

PubMed Central

Langhanns, Christine; Müller, Hermann

2018-01-01

Motor-cognitive dual tasks have been intensely studied and it has been demonstrated that even well practiced movements like walking show signs of interference when performed concurrently with a challenging cognitive task. Typically walking speed is reduced, at least in elderly persons. In contrast to these findings, some authors report an increased movement frequency under dual-task conditions, which they call hastening. A tentative explanation has been proposed, assuming that the respective movements are governed by an automatic control regime. Though, under single-task conditions, these automatic processes are supervised by “higher-order” cognitive control processes. However, when a concurrent cognitive task binds all cognitive resources, the automatic process is freed from the detrimental effect of cognitive surveillance, allowing higher movement frequencies. Fast rhythmic movements (>1 Hz) should more likely be governed by such an automatic process than low frequency discrete repetitive movements. Fifteen subjects performed two repetitive movements under single and dual-task condition, that is, in combination with a mental calculation task. According to the expectations derived from the explanatory concept, we found an increased movement frequency under dual-task conditions only for the fast rhythmic movement (paddleball task) but not for the slower discrete repetitive task (pegboard task). fNIRS measurements of prefrontal cortical load confirmed the idea of an automatic processing in the paddleball task, whereas the pegboard task seems to be more controlled by processes interfering with the calculation related processing. PMID:29887815

How Do Children Coordinate Simultaneous Upper and Lower Extremity Tasks? The Development of Dual Motor Task Coordination.

ERIC Educational Resources Information Center

Getchell, Nancy; Whitall, Jill

2003-01-01

Compared coupling characteristics of clapping simultaneous with walking or galloping, consistency across trials, and phasing variability among 4-, 6-, 8-, and 10-year-olds. Found that for walk/clap tasks, children adopted adult-like coupling patterns by age 8 and with the same consistency by age 10. Across age, children became less variable in…

Ginkgo biloba special extract LI 1370 improves dual-task walking in patients with MCI: a randomised, double-blind, placebo-controlled exploratory study.

PubMed

Gschwind, Yves J; Bridenbaugh, Stephanie A; Reinhard, Sarah; Granacher, Urs; Monsch, Andreas U; Kressig, Reto W

2017-08-01

In patients with mild cognitive impairment (MCI), gait instability, particularly in dual-task situations, has been associated with impaired executive function and an increased fall risk. Ginkgo biloba extract (GBE) could be an effective mean to improve gait stability. This study investigated the effect of GBE on spatio-temporal gait parameters of MCI patients while walking under single and dual-task conditions. Fifty patients aged 50-85 years with MCI and associated dual-task-related gait impairment participated in this randomised, double-blind, placebo-controlled, exploratory phase IV drug trial. Intervention group (IG) patients received GBE (Symfona ® forte 120 mg) twice-daily for 6 months while control group (CG) patients received placebo capsules. A 6-month open-label phase with identical GBE dosage followed. Gait was quantified at months 0, 3, 6 and 12. After 6 months, dual-task-related cadence increased in the IG compared to the CG (p = 0.019, d = 0.71). No significant changes, but GBE-associated numerical non-significant trends were found after 6-month treatment for dual-task-related gait velocity and stride time variability. Findings suggest that 120 mg of GBE twice-daily for at least 6 months may improve dual-task-related gait performance in patients with MCI. The observed gait improvements add to the understanding of the self-reported unspecified improvements among MCI patients when treated with standardised GBE.

Quantification of gait changes in subjects with visual height intolerance when exposed to heights.

PubMed

Schniepp, Roman; Kugler, Günter; Wuehr, Max; Eckl, Maria; Huppert, Doreen; Huth, Sabrina; Pradhan, Cauchy; Jahn, Klaus; Brandt, Thomas

2014-01-01

Visual height intolerance (vHI) manifests as instability at heights with apprehension of losing balance or falling. We investigated contributions of visual feedback and attention on gait performance of subjects with vHI. Sixteen subjects with vHI walked over a gait mat (GAITRite®) on a 15-m-high balcony and at ground-level. Subjects walked at different speeds (slow, preferred, fast), during changes of the visual input (gaze straight/up/down; eyes open/closed), and while doing a cognitive task. An rmANOVA with the factors "height situation" and "gait condition" was performed. Subjects were also asked to estimate the height of the balcony over ground level. The individual estimates were used for correlations with the gait parameters. Study participants walked slower at heights, with reduced cadence and stride length. The double support phases were increased (all p < 0.01), which correlated with the estimated height of the balcony (R (2) = 0.453, p < 0.05). These changes were still present when walking with upward gaze or closure of the eyes. Under the conditions walking and looking down to the floor of the balcony, during dual-task and fast walking, there were no differences between the gait performance on the balcony and at ground-level. The found gait changes are features of a cautious gait control. Internal, cognitive models with anxiety play an important role for vHI; gait was similarly affected when the visual perception of the depth was prevented. Improvement by dual task at heights may be associated by a reduction of the anxiety level. It is conceivable that mental distraction by dual task or increasing the walking speed might be useful recommendations to reduce the imbalance during locomotion in subjects susceptible to vHI.

Do frailty and cognitive impairment affect dual-task cost during walking in the oldest old institutionalized patients?

PubMed

Cadore, Eduardo L; Casas-Herrero, Alvaro; Zambom-Ferraresi, Fabricio; Martínez-Ramírez, Alicia; Millor, Nora; Gómez, Marisol; Moneo, Ana B Bays; Izquierdo, Mikel

2015-12-01

The objective of this study was to investigate dual-task costs in several elderly populations, including robust oldest old, frail oldest old with MCI, frail oldest old without MCI, and frail elderly with dementia. Sixty-four elderly men and women categorized into frail without MCI (age 93.4 ± 3.2 years, n = 20), frail with MCI (age 92.4 ± 4.2 years, n = 13), robust (age 88.2 ± 4.1 years, n = 10), and patients with dementia (age 88.1 ± 5.1 years, n = 21). Five-meter gait ability and timed-up-and-go (TUG) tests with single and dual-task performance were assessed in the groups. Dual-task cost in both 5-m habitual gait velocity test and TUG test was calculated by the time differences between single and dual-task performance. The robust group exhibited better 5-m gait and TUG test performances in the single and dual-task conditions compared with the other three groups (P < 0.001), and the frail and frail + MCI groups exhibited better performances than the dementia group (P < 0.001). No significant differences were observed between the frail and frail + MCI groups. However, all groups exhibited lower gait velocities in the verbal and arithmetic task conditions, but the dual-task cost of the groups were similar. Robust individuals exhibited superior single and dual-task walking performances than the other three groups, and the frail and frail + MCI individuals exhibited performances that were superior to those of the patients with dementia. However, the dual-task costs, i.e., the changes in gait performance when elderly participants switch from a single to a dual task, were similar among all four of the investigated groups. Therefore, these results demonstrated that the magnitude of the impairment in gait pattern is independent of frailty and cognitive impairment status.

Age-related cognitive task effects on gait characteristics: do different working memory components make a difference?

PubMed

Qu, Xingda

2014-10-27

Though it is well recognized that gait characteristics are affected by concurrent cognitive tasks, how different working memory components contribute to dual task effects on gait is still unknown. The objective of the present study was to investigate dual-task effects on gait characteristics, specifically the application of cognitive tasks involving different working memory components. In addition, we also examined age-related differences in such dual-task effects. Three cognitive tasks (i.e. 'Random Digit Generation', 'Brooks' Spatial Memory', and 'Counting Backward') involving different working memory components were examined. Twelve young (6 males and 6 females, 20 ~ 25 years old) and 12 older participants (6 males and 6 females, 60 ~ 72 years old) took part in two phases of experiments. In the first phase, each cognitive task was defined at three difficulty levels, and perceived difficulty was compared across tasks. The cognitive tasks perceived to be equally difficult were selected for the second phase. In the second phase, four testing conditions were defined, corresponding to a baseline and the three equally difficult cognitive tasks. Participants walked on a treadmill at their self-selected comfortable speed in each testing condition. Body kinematics were collected during treadmill walking, and gait characteristics were assessed using spatial-temporal gait parameters. Application of the concurrent Brooks' Spatial Memory task led to longer step times compared to the baseline condition. Larger step width variability was observed in both the Brooks' Spatial Memory and Counting Backward dual-task conditions than in the baseline condition. In addition, cognitive task effects on step width variability differed between two age groups. In particular, the Brooks' Spatial Memory task led to significantly larger step width variability only among older adults. These findings revealed that cognitive tasks involving the visuo-spatial sketchpad interfered with gait more severely in older versus young adults. Thus, dual-task training, in which a cognitive task involving the visuo-spatial sketchpad (e.g. the Brooks' Spatial Memory task) is concurrently performed with walking, could be beneficial to mitigate impairments in gait among older adults.

Walking and cognition, but not symptoms, correlate with dual task cost of walking in multiple sclerosis.

PubMed

Motl, Robert W; Sosnoff, Jacob J; Dlugonski, Deirdre; Pilutti, Lara A; Klaren, Rachel; Sandroff, Brian M

2014-03-01

Performing a cognitive task while walking results in a reduction of walking performance among persons with MS. To date, very little is known about correlates of this dual task cost (DTC) of walking in MS. We examined walking performance, cognitive processing speed, and symptoms of fatigue, depression, anxiety, and pain as correlates of DTC of walking in MS. 82 persons with MS undertook a 6-min walk test (6MWT) and completed the Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), Short-form of the McGill Pain Questionnaire (SF-MPQ), Hospital Anxiety and Depression Scale (HADS), and self-reported Expanded Disability Status Scale (SR-EDSS). The participants completed 4 trials of walking at a self-selected pace on an electronic walkway that recorded spatiotemporal parameters of gait. The first 2 trials were performed without a cognitive task, whereas the second 2 trials were completed while performing a modified Word List Generation task. There were significant and large declines in gait performance with the addition of a cognitive task for velocity (p<.001, η2=.52), cadence (p<.001, η2=.49), and step length (p<.001, η2=.23). 6MWT and SDMT scores correlated with DTC for velocity (r=-.41, p<.001 and r=-.32, p<.001, respectively) and step length (r=-.45, p<.001 and r=-.37, p<.001, respectively); there were no significant associations between FSS, SF-MPQ, and HADS scores with the DTC of walking. Regression analyses indicated that 6MW, but not SDMT, explained variance in DTC for velocity (ΔR2=.11, p<.001) and step length (ΔR2=.13, p<.001), after controlling for SR-EDSS scores. Walking performance might be a target of interventions for reducing the DTC of walking in MS. Copyright © 2013 Elsevier B.V. All rights reserved.

Cognitive-motor interference during fine and gross motor tasks in children with Developmental Coordination Disorder (DCD).

PubMed

Schott, Nadja; El-Rajab, Inaam; Klotzbier, Thomas

2016-10-01

While typically developing children produce relatively automatized postural control processes, children with DCD seem to exhibit an automatization deficit. Dual tasks with various cognitive loads seem to be an effective way to assess the automatic deficit hypothesis. The aims of the study were: (1) to examine the effect of a concurrent cognitive task on fine and gross motor tasks in children with DCD, and (2) to determine whether the effect varied with different difficulty levels of the concurrent task. We examined dual-task performance (Trail-Making-Test, Trail-Walking-Test) in 20 children with DCD and 39 typically developing children. Based on the idea of the Trail-Making-Test, participants walked along a fixed pathway, following a prescribed path, delineated by target markers of (1) increasing sequential numbers, and (2) increasing sequential numbers and letters. The motor and cognitive dual-task effects (DTE) were calculated for each task. Regardless of the cognitive task, children with DCD performed equally well in fine and gross motor tasks, and were slower in the dual task conditions than under single task-conditions, compared with children without DCD. Increased cognitive task complexity resulted in slow trail walking as well as slower trail tracing. The motor interference for the gross motor tasks was least for the simplest conditions and greatest for the complex conditions and was more pronounced in children with DCD. Cognitive interference was low irrespective of the motor task. Children with DCD show a different approach to allocation of cognitive resources, and have difficulties making motor skills automatic. The latter notion is consistent with impaired cerebellar function and the "automatization deficit hypothesis", suggesting that any deficit in the automatization process will appear if conscious monitoring of the motor skill is made more difficult by integrating another task requiring attentional resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Association between High Neuroticism-Low Extraversion and Dual-Task Performance during Walking While Talking in Non-demented Older Adults

PubMed Central

LeMonda, Brittany C.; Mahoney, Jeannette R.; Verghese, Joe; Holtzer, Roee

2016-01-01

The Walking While Talking (WWT) dual-task paradigm is a mobility stress test that predicts major outcomes, including falls, frailty, disability, and mortality in aging. Certain personality traits, such as neuroticism, extraversion, and their combination, have been linked to both cognitive and motor outcomes. We examined whether individual differences in personality dimensions of neuroticism and extraversion predicted dual-task performance decrements (both motor and cognitive) on a WWT task in non-demented older adults. We hypothesized that the combined effect of high neuroticism-low extraversion would be related to greater dual-task costs in gait velocity and cognitive performance in non-demented older adults. Participants (N = 295; age range, = 65–95 years; female = 164) completed the Big Five Inventory and WWT task involving concurrent gait and a serial 7's subtraction task. Gait velocity was obtained using an instrumented walkway. The high neuroticism-low extraversion group incurred greater dual-task costs (i.e., worse performance) in both gait velocity {95% confidence interval (CI) [−17.68 to −3.07]} and cognitive performance (95% CI [−19.34 to −2.44]) compared to the low neuroticism-high extraversion group, suggesting that high neuroticism-low extraversion interferes with the allocation of attentional resources to competing task demands during the WWT task. Older individuals with high neuroticism-low extraversion may be at higher risk for falls, mobility decline and other adverse outcomes in aging. PMID:26527241

Balance training with multi-task exercises improves fall-related self-efficacy, gait, balance performance and physical function in older adults with osteoporosis: a randomized controlled trial.

PubMed

Halvarsson, Alexandra; Franzén, Erika; Ståhle, Agneta

2015-04-01

To evaluate the effects of a balance training program including dual- and multi-task exercises on fall-related self-efficacy, fear of falling, gait and balance performance, and physical function in older adults with osteoporosis with an increased risk of falling and to evaluate whether additional physical activity would further improve the effects. Randomized controlled trial, including three groups: two intervention groups (Training, or Training+Physical activity) and one Control group, with a 12-week follow-up. Stockholm County, Sweden. Ninety-six older adults, aged 66-87, with verified osteoporosis. A specific and progressive balance training program including dual- and multi-task three times/week for 12 weeks, and physical activity for 30 minutes, three times/week. Fall-related self-efficacy (Falls Efficacy Scale-International), fear of falling (single-item question - 'In general, are you afraid of falling?'), gait speed with and without a cognitive dual-task at preferred pace and fast walking (GAITRite®), balance performance tests (one-leg stance, and modified figure of eight), and physical function (Late-Life Function and Disability Instrument). Both intervention groups significantly improved their fall-related self-efficacy as compared to the controls (p ≤ 0.034, 4 points) and improved their balance performance. Significant differences over time and between groups in favour of the intervention groups were found for walking speed with a dual-task (p=0.003), at fast walking speed (p=0.008), and for advanced lower extremity physical function (p=0.034). This balance training program, including dual- and multi-task, improves fall-related self-efficacy, gait speed, balance performance, and physical function in older adults with osteoporosis. © The Author(s) 2014.

Factors Contributing to Single- and Dual-Task Timed "Up & Go" Test Performance in Middle-Aged and Older Adults Who Are Active and Dwell in the Community.

PubMed

Chen, Hui-Ya; Tang, Pei-Fang

2016-03-01

Dual-task Timed "Up & Go" (TUG) tests are likely to have applications different from those of a single-task TUG test and may have different contributing factors. The purpose of this study was to compare factors contributing to performance on single- and dual-task TUG tests. This investigation was a cross-sectional study. Sixty-four adults who were more than 50 years of age and dwelled in the community were recruited. Interviews and physical examinations were performed to identify potential contributors to TUG test performance. The time to complete the single-task TUG test (TUGsingle) or the dual-task TUG test, which consisted of completing the TUG test while performing a serial subtraction task (TUGcognitive) or while carrying water (TUGmanual), was measured. Age, hip extensor strength, walking speed, general mental function, and Stroop scores for word and color were significantly associated with performance on all TUG tests. Hierarchical multiple regression models, without the input of walking speed, revealed different independent factors contributing to TUGsingle performance (Mini-Mental Status Examination score, β=-0.32), TUGmanual performance (age, β=0.35), and TUGcognitive performance (Stroop word score, β=-0.40; Mini-Mental Status Examination score, β=-0.31). At least 40% of the variance in the performance on the 3 TUG tests was not explained by common clinical measures, even when the factor of walking speed was considered. However, this study successfully identified some important factors contributing to performance on different TUG tests, and other studies have reported similar findings for single-task TUG test and dual-task gait performance. Although the TUGsingle and the TUGcognitive shared general mental function as a common factor, the TUGmanual was uniquely influenced by age and the TUGcognitive was uniquely influenced by focused attention. These results suggest that both common and unique factors contribute to performance on single- and dual-task TUG tests and suggest important applications of the combined use of the 3 TUG tests. © 2016 American Physical Therapy Association.

Psychophysiological response to cognitive workload during symmetrical, asymmetrical and dual-task walking.

PubMed

Knaepen, Kristel; Marusic, Uros; Crea, Simona; Rodríguez Guerrero, Carlos D; Vitiello, Nicola; Pattyn, Nathalie; Mairesse, Olivier; Lefeber, Dirk; Meeusen, Romain

2015-04-01

Walking with a lower limb prosthesis comes at a high cognitive workload for amputees, possibly affecting their mobility, safety and independency. A biocooperative prosthesis which is able to reduce the cognitive workload of walking could offer a solution. Therefore, we wanted to investigate whether different levels of cognitive workload can be assessed during symmetrical, asymmetrical and dual-task walking and to identify which parameters are the most sensitive. Twenty-four healthy subjects participated in this study. Cognitive workload was assessed through psychophysiological responses, physical and cognitive performance and subjective ratings. The results showed that breathing frequency and heart rate significantly increased, and heart rate variability significantly decreased with increasing cognitive workload during walking (p<.05). Performance measures (e.g., cadence) only changed under high cognitive workload. As a result, psychophysiological measures are the most sensitive to identify changes in cognitive workload during walking. These parameters reflect the cognitive effort necessary to maintain performance during complex walking and can easily be assessed regardless of the task. This makes them excellent candidates to feed to the control loop of a biocooperative prosthesis in order to detect the cognitive workload. This information can then be used to adapt the robotic assistance to the patient's cognitive abilities. Copyright © 2015 Elsevier B.V. All rights reserved.

Dual-task gait differences in female and male adolescents following sport-related concussion.

PubMed

Howell, David R; Stracciolini, Andrea; Geminiani, Ellen; Meehan, William P

2017-05-01

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age=15.0±2.1 years, 7.5±3.0 days post-injury) and 51 controls (51% female, mean age=14.4±2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0±18.0) and males (27.8±18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (-19.7%±10.0% vs. -11.3%±9.2%, p=0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13±0.11m vs. 1.26±0.11m, p=0.001; males: 1.14±0.14m vs. 1.22±0.15m, p=0.04) and dual-task gait (females: 0.99±0.10m vs. 1.10±0.11m, p=0.001; males: 1.00±0.13m vs. 1.08±0.14m, p=0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait. Copyright © 2017 Elsevier B.V. All rights reserved.

Risk Factors for Falls in Older Adults With Mild Cognitive Impairment and Mild Alzheimer Disease.

PubMed

Ansai, Juliana Hotta; de Andrade, Larissa Pires; Masse, Fernando Arturo Arriagada; Gonçalves, Jessica; de Medeiros Takahashi, Anielle Cristhine; Vale, Francisco Assis Carvalho; Rebelatto, José Rubens

2017-03-03

Understanding fall risk factors in people with mild cognitive impairment (MCI) and Alzheimer disease (AD) can help to establish specific plans for prevention of falls. The purpose of this study was to identify fall risk factors in older adults with MCI and mild AD. A prospective study was conducted with community-dwelling older adults (40 MCI; 38 mild AD). The assessments consisted of sociodemographic and health variables, caloric expenditure, functional status, functional mobility (10-m walk test, dual-task test, and transition Timed Up and Go phases), cognitive domains, and depressive symptoms. Falls were recorded for 6 months by a falls calendar and monthly telephone calls. Falls were reported in 52.6% and 51.4% of people with MCI and mild AD, respectively. Among people with MCI, lower functional status, higher time spent on walk and dual task tests, and higher depressive symptom scores were associated with falls. Higher time spent on the dual-task test was independently associated with falls. Among people with mild AD, falls were associated with lower time spent on the walk test and turn-to-sit phase, and a higher visuospatial domain score. Lower time spent on the turn-to-sit phase was identified as an independent predictor of falls. Careful attention should be given to dual-task and turn-to-sit activities when detecting risk of falls among older people with MCI and mild AD.

Gait analysis in demented subjects: Interests and perspectives

PubMed Central

Beauchet, Olivier; Allali, Gilles; Berrut, Gilles; Hommet, Caroline; Dubost, Véronique; Assal, Frédéric

2008-01-01

Gait disorders are more prevalent in dementia than in normal aging and are related to the severity of cognitive decline. Dementia-related gait changes (DRGC) mainly include decrease in walking speed provoked by a decrease in stride length and an increase in support phase. More recently, dual-task related changes in gait were found in Alzheimer’s disease (AD) and non-Alzheimer dementia, even at an early stage. An increase in stride-to-stride variability while usual walking and dual-tasking has been shown to be more specific and sensitive than any change in mean value in subjects with dementia. Those data show that DRGC are not only associated to motor disorders but also to problem with central processing of information and highlight that dysfunction of temporal and frontal lobe may in part explain gait impairment among demented subjects. Gait assessment, and more particularly dual-task analysis, is therefore crucial in early diagnosis of dementia and/or related syndromes in the elderly. Moreover, dual-task disturbances could be a specific marker of falling at a pre-dementia stage. PMID:18728766

Association Between Gait and Dual Task With Cognitive Domains in Older People With Cognitive Impairment.

PubMed

Ansai, Juliana Hotta; Andrade, Larissa Pires de; Rossi, Paulo Giusti; Almeida, Mariana Luciano; Carvalho Vale, Francisco Assis; Rebelatto, José Rubens

2017-09-13

The authors investigated whether impaired gait and dual-task performances are associated with specific cognitive domains among older people with preserved cognition (PC), mild cognitive impairment (MCI), and mild Alzheimer's disease (AD). The sample comprised 40 older adults with PC, 40 with MCI, and 38 with mild AD. The assessment consisted of gait (measured by 10-m walk test and Timed Up and Go Test [TUGT]), dual task (measured by TUGT associated with a cognitive-motor task of calling a phone number), and cognition (domains of the Addenbrooke Cognitive Examination-Revised and Frontal Assessment Battery [FAB]). For data analysis, the Pearson product-moment correlation and the backward stepwise linear regression were conducted. Language, fluency, and visuospatial domains predicted the 10-m walk test measure specifically in PC, MCI, and AD groups. Only the visuospatial domain was independently associated with the TUGT measure in the MCI and AD groups. FAB score, language domain, and FAB score and fluency domain were the strongest predictors for the isolated cognitive-motor task measure in the PC, MCI, and AD groups, respectively. The visuospatial domain was independently associated with the dual-task test measure in all 3 groups. The study findings demonstrate the influence of specific cognitive domains in daily mobility tasks in people with different cognitive profiles.

Over-focused? The relation between patients' inclination for conscious control and single- and dual-task motor performance after stroke.

PubMed

Denneman, R P M; Kal, E C; Houdijk, H; Kamp, J van der

2018-05-01

Many stroke patients are inclined to consciously control their movements. This is thought to negatively affect patients' motor performance, as it disrupts movement automaticity. However, it has also been argued that conscious control may sometimes benefit motor performance, depending on the task or patientś motor or cognitive capacity. To assess whether stroke patients' inclination for conscious control is associated with motor performance, and explore whether the putative association differs as a function of task (single- vs dual) or patientś motor and cognitive capacity. Univariate and multivariate linear regression analysis were used to assess associations between patients' disposition to conscious control (i.e., Conscious Motor Processing subscale of Movement-Specific Reinvestment Scale; MSRS-CMP) and single-task (Timed-up-and-go test; TuG) and motor dual-task costs (TuG while tone counting; motor DTC%). We determined whether these associations were influenced by patients' walking speed (i.e., 10-m-walk test) and cognitive capacity (i.e., working memory, attention, executive function). Seventy-eight clinical stroke patients (<6 months post-stroke) participated. Patients' conscious control inclination was not associated with single-task TuG performance. However, patients with a strong inclination for conscious control showed higher motor DTC%. These associations were irrespective of patients' motor and cognitive abilities. Patients' disposition for conscious control was not associated with single task motor performance, but was associated with higher motor dual task costs, regardless of patients' motor or cognitive abilities. Therapists should be aware that patients' conscious control inclination can influence their dual-task performance while moving. Longitudinal studies are required to test whether reducing patients' disposition for conscious control would improve dual-tasking post-stroke. Copyright © 2018 Elsevier B.V. All rights reserved.

Does a multicomponent exercise program improve dual-task performance in amnestic mild cognitive impairment? A randomized controlled trial.

PubMed

Makizako, Hyuma; Doi, Takehiko; Shimada, Hiroyuki; Yoshida, Daisuke; Tsutsumimoto, Kota; Uemura, Kazuki; Suzuki, Takao

2012-12-01

There has been much interest in exercise interventions as a primary behavioral prevention strategy against cognitive decline. The aim of this study was to evaluate the effect of a multicomponent exercise program on physical and dual-task performances in community-dwelling older adults with amnestic mild cognitive impairment (aMCI). Fifty older adults (23 women) with aMCI (mean age, 76 years) were randomized to an intervention (n=25) or a control group (n=25). The intervention group received a multicomponent exercise program for 90 minutes/day, 2 days/week, or 40 times over six months. The multicomponent exercises included aerobic exercise, muscle strength training and postural balance retraining, which was conducted under multi-task conditions to stimulate attention and memory. Participants in the control group attended two health promotion education classes within six months. Physical and dual-task performances were measured before randomization and after six months. Dual-task performances using reaction times with balance and cognitive demands were measured. The improvement effects on dual-task performances with both balance and cognitive demands were not statistically significant: reaction time with balance demand F1,45=3.3, p=0.07, and cognitive demand F1,45=2.6, p=0.12. However, there was a significant group-by-time interaction on maximal walking speed, which decreased significantly in the control group (F1,45=5.9, p=0.02). This six-month multicomponent exercise program improved maximal walking speed in older adults with aMCI; however, it did not improve dual-task performances assessed by reaction times.

Quantification of gait changes in subjects with visual height intolerance when exposed to heights

PubMed Central

Schniepp, Roman; Kugler, Günter; Wuehr, Max; Eckl, Maria; Huppert, Doreen; Huth, Sabrina; Pradhan, Cauchy; Jahn, Klaus; Brandt, Thomas

2014-01-01

Introduction: Visual height intolerance (vHI) manifests as instability at heights with apprehension of losing balance or falling. We investigated contributions of visual feedback and attention on gait performance of subjects with vHI. Materials and Methods: Sixteen subjects with vHI walked over a gait mat (GAITRite®) on a 15-m-high balcony and at ground-level. Subjects walked at different speeds (slow, preferred, fast), during changes of the visual input (gaze straight/up/down; eyes open/closed), and while doing a cognitive task. An rmANOVA with the factors “height situation” and “gait condition” was performed. Subjects were also asked to estimate the height of the balcony over ground level. The individual estimates were used for correlations with the gait parameters. Results: Study participants walked slower at heights, with reduced cadence and stride length. The double support phases were increased (all p < 0.01), which correlated with the estimated height of the balcony (R2 = 0.453, p < 0.05). These changes were still present when walking with upward gaze or closure of the eyes. Under the conditions walking and looking down to the floor of the balcony, during dual-task and fast walking, there were no differences between the gait performance on the balcony and at ground-level. Discussion: The found gait changes are features of a cautious gait control. Internal, cognitive models with anxiety play an important role for vHI; gait was similarly affected when the visual perception of the depth was prevented. Improvement by dual task at heights may be associated by a reduction of the anxiety level. Conclusion: It is conceivable that mental distraction by dual task or increasing the walking speed might be useful recommendations to reduce the imbalance during locomotion in subjects susceptible to vHI. PMID:25538595

Virtual reality for gait training: can it induce motor learning to enhance complex walking and reduce fall risk in patients with Parkinson's disease?

PubMed

Mirelman, Anat; Maidan, Inbal; Herman, Talia; Deutsch, Judith E; Giladi, Nir; Hausdorff, Jeffrey M

2011-02-01

Gait and cognitive disturbances are common in Parkinson's disease (PD). These deficits exacerbate fall risk and difficulties with mobility, especially during complex or dual-task walking. Traditional gait training generally fails to fully address these complex gait activities. Virtual reality (VR) incorporates principles of motor learning while delivering engaging and challenging training in complex environments. We hypothesized that VR may be applied to address the multifaceted deficits associated with fall risk in PD. Twenty patients received 18 sessions (3 per week) of progressive intensive treadmill training with virtual obstacles (TT + VR). Outcome measures included gait under usual-walking and dual-task conditions and while negotiating physical obstacles. Cognitive function and functional performance were also assessed. Patients were 67.1 ± 6.5 years and had a mean disease duration of 9.8 ± 5.6 years. Posttraining, gait speed significantly improved during usual walking, during dual task, and while negotiating overground obstacles. Dual-task gait variability decreased (ie, improved) and Trail Making Test times (parts A and B) improved. Gains in functional performance measures and retention effects, 1 month later, were also observed. To our knowledge, this is the first time that TT + VR has been used for gait training in PD. The results indicate that TT + VR is viable in PD and may significantly improve physical performance, gait during complex challenging conditions, and even certain aspects of cognitive function. These findings have important implications for understanding motor learning in the presence of PD and for treating fall risk in PD, aging, and others who share a heightened risk of falls.

Cellular Telephone Dialing Influences Kinematic and Spatiotemporal Gait Parameters in Healthy Adults.

PubMed

Seymour, Kelly M; Higginson, Christopher I; DeGoede, Kurt M; Bifano, Morgan K; Orr, Rachel; Higginson, Jill S

2016-01-01

Gait speed is typically reduced when individuals simultaneously perform other tasks. However, the impact of dual tasking on kinetic and kinematic gait parameters is unclear because these vary with gait speed. The objective of this study was to identify whether dual tasking impacts gait in healthy adults when speed is constant. Twenty-two healthy adults dialed a cell phone during treadmill walking at a self-selected speed while kinetic, kinematic, and spatial parameters were recorded. Results indicated that dual tasking did not impact phone dialing speed, but increased stride width, peak knee flexion during stance, and peak plantarflexion, and decreased knee and ankle range of motion. Dual tasking appears to influence kinematic gait variables in a manner consistent with promotion of stability.

Cognitive-Based Interventions to Improve Mobility: A Systematic Review and Meta-analysis.

PubMed

Marusic, Uros; Verghese, Joe; Mahoney, Jeannette R

2018-06-01

A strong relation between cognition and mobility has been identified in aging, supporting a role for enhancement mobility through cognitive-based interventions. However, a critical evaluation of the consistency of treatment effects of cognitive-based interventions is currently lacking. The objective of this study was 2-fold: (1) to review the existing literature on cognitive-based interventions aimed at improving mobility in older adults and (2) to assess the clinical effectiveness of cognitive interventions on gait performance. A systematic review of randomized controlled trials (RCT) of cognitive training interventions for improving simple (normal walking) and complex (dual task walking) gait was conducted in February 2018. Older adults without major cognitive, psychiatric, neurologic, and/or sensory impairments were included. Random effect meta-analyses and a subsequent meta-regression were performed to generate overall cognitive intervention effects on single- and dual-task walking conditions. Ten RCTs met inclusion criteria, with a total of 351 participants included in this meta-analysis. Cognitive training interventions revealed a small effect of intervention on complex gait [effect size (ES) = 0.47, 95% confidence interval (CI) 0.13 to 0.81, P = .007, I 2  = 15.85%], but not simple gait (ES = 0.35, 95% CI -0.01 to 0.71, P = .057, I 2  = 57.32%). Moreover, a meta-regression analysis revealed that intervention duration, training frequency, total number of sessions, and total minutes spent in intervention were not significant predictors of improvement in dual-task walking speed, though there was a suggestive trend toward a negative association between dual-task walking speed improvements and individual training session duration (P = .067). This meta-analysis provides support for the fact that cognitive training interventions can improve mobility-related outcomes, especially during challenging walking conditions requiring higher-order executive functions. Additional evidence from well-designed large-scale randomized clinical trials is warranted to confirm the observed effects. Copyright © 2018 AMDA – The Society for Post-Acute and Long-Term Care Medicine. All rights reserved.

Gait parameter risk factors for falls under simple and dual task conditions in cognitively impaired older people.

PubMed

Taylor, Morag E; Delbaere, Kim; Mikolaizak, A Stefanie; Lord, Stephen R; Close, Jacqueline C T

2013-01-01

Impaired gait may contribute to the increased rate of falls in cognitively impaired older people. We investigated whether gait under simple and dual task conditions could predict falls in this group. The study sample consisted of 64 community dwelling older people with mild to moderate cognitive impairment. Participants walked at their preferred speed under three conditions: (a) simple walking, (b) walking while carrying a glass of water and (c) walking while counting backwards from 30. Spatiotemporal gait parameters were measured using the GAITRite(®) mat. Falls were recorded prospectively for 12months with the assistance of carers. Twenty-two (35%) people fell two or more times in the 12month follow-up period. There was a significant main effect of gait condition and a significant main effect of faller status for mean value measures (velocity, stride length, double support time and stride width) and for variability measures (swing time variability and stride length variability). Examination of individual gait parameters indicated that the multiple fallers walked more slowly, had shorter stride length, spent longer time in double support, had a wider support width and showed more variability in stride length and swing time (p<0.05). There was no significant interaction between gait condition and faller status for any of the gait variables. In conclusion, dual task activities adversely affect gait in cognitively impaired older people. Multiple fallers performed worse in each gait condition but the addition of a functional or cognitive secondary task provided no added benefit in discriminating fallers from non-fallers with cognitive impairment. Copyright © 2012 Elsevier B.V. All rights reserved.

The reliability and preliminary validity of game-based fall risk assessment in community-dwelling older adults.

PubMed

Yamada, Minoru; Aoyama, Tomoki; Nakamura, Masatoshi; Tanaka, Buichi; Nagai, Koutatsu; Tatematsu, Noriatsu; Uemura, Kazuki; Nakamura, Takashi; Tsuboyama, Tadao; Ichihashi, Noriaki

2011-01-01

The purpose of this study was to examine whether the Nintendo Wii Fit program could be used for fall risk assessment in healthy, community-dwelling older adults. Forty-five community-dwelling older women participated in this study. The "Basic Step" and "Ski Slalom" modules were selected from the Wii Fit game program. The following 5 physical performance tests were performed: the 10-m walk test under single- and dual-task conditions, the Timed Up and Go test under single- and dual-task conditions, and the Functional Reach test. Compared with the faller group, the nonfaller group showed a significant difference in the Basic Step (P < .001) and a nonsignificant difference in the Ski Slalom (P = .453). The discriminating criterion between the 2 groups was a score of 111 points on the Basic Step (P < .001). The Basic Step showed statistically significant, moderate correlations between the dual-task lag of walking (r = -.547) and the dual-task lag of the Timed Up and Go test (r = -.688). These results suggest that game-based fall risk assessment using the Basic Step has a high generality and is useful in community-dwelling older adults. Copyright © 2011 Mosby, Inc. All rights reserved.

Behavioral and Neural Correlates of Imagined Walking and Walking-While-Talking in the Elderly

PubMed Central

Blumen, Helena M.; Holtzer, Roee; Brown, Lucy L.; Gazes, Yunglin; Verghese, Joe

2014-01-01

Cognition is important for locomotion and gait decline increases the risk for morbidity, mortality, cognitive decline, and dementia. Yet, the neural correlates of gait are not well established, because most neuroimaging methods cannot image the brain during locomotion. Imagined gait protocols overcome this limitation. This study examined the behavioral and neural correlates of a new imagined gait protocol that involved imagined walking (iW), imagined talking (iT), and imagined walking-while-talking (iWWT). In Experiment 1, 82 cognitively-healthy older adults (M = 80.45) walked (W), iW, walked while talking (WWT) and iWWT. Real and imagined walking task times were strongly correlated, particularly real and imagined dual-task times (WWT and iWWT). In Experiment 2, 33 cognitively-healthy older adults (M = 73.03) iW, iT, and iWWT during functional Magnetic Resonance Imaging. A multivariate Ordinal Trend (OrT) Covariance analysis identified a pattern of brain regions that: 1) varied as a function of imagery task difficulty (iW, iT and iWWT), 2) involved cerebellar, precuneus, supplementary motor and other prefrontal regions, and 3) were associated with kinesthetic imagery ratings and behavioral performance during actual WWT. This is the first study to compare the behavioral and neural correlates of imagined gait in single and dual-task situations, an issue that is particularly relevant to elderly populations. These initial findings encourage further research and development of this imagined gait protocol as a tool for improving gait and cognition among the elderly. PMID:24522972

Strength-balance supplemented with computerized cognitive training to improve dual task gait and divided attention in older adults: a multicenter randomized-controlled trial.

PubMed

van het Reve, Eva; de Bruin, Eling D

2014-12-15

Exercise interventions often do not combine physical and cognitive training. However, this combination is assumed to be more beneficial in improving walking and cognitive functioning compared to isolated cognitive or physical training. A multicenter parallel randomized controlled trial was conducted to compare a motor to a cognitive-motor exercise program. A total of 182 eligible residents of homes-for-the-aged (n = 159) or elderly living in the vicinity of the homes (n = 23) were randomly assigned to either strength-balance (SB) or strength-balance-cognitive (SBC) training. Both groups conducted similar strength-balance training during 12 weeks. SBC additionally absolved computerized cognitive training. Outcomes were dual task costs of walking, physical performance, simple reaction time, executive functions, divided attention, fear of falling and fall rate. Participants were analysed with an intention to treat approach. The 182 participants (mean age ± SD: 81.5 ± 7.3 years) were allocated to either SB (n = 98) or SBC (n = 84). The attrition rate was 14.3%. Interaction effects were observed for dual task costs of step length (preferred walking speed: F(1,174) = 4.94, p = 0.028, η2 = 0.027, fast walking speed: F(1,166) = 6.14, p = 0.009, η2 = 0.040) and dual task costs of the standard deviation of step length (F(1,166) = 6.14, p = 0.014, η2 = 0.036), in favor of SBC. Significant interactions in favor of SBC revealed for in gait initiation (F(1,166) = 9.16, p = 0.003, η2 = 0.052), 'reaction time' (F(1,180) = 5.243, p = 0.023, η² = 0.028) & 'missed answers' (F(1,180) = 11.839, p = 0.001, η² = 0.062) as part of the test for divided attention. Within-group comparison revealed significant improvements in dual task costs of walking (preferred speed; velocity (p = 0.002), step time (p = 0.018), step length (p = 0.028), fast speed; velocity (p < 0.001), step time (p = 0.035), step length (p = 0.001)), simple reaction time (p < 0.001), executive functioning (Trail making test B; p < 0.001), divided attention (p < 0.001), fear of falling (p < 0.001), and fall rate (p < 0.001). Combining strength-balance training with specific cognitive training has a positive additional effect on dual task costs of walking, gait initiation, and divided attention. The findings further confirm previous research showing that strength-balance training improves executive functions and reduces falls. This trial has been registered under ISRCTN75134517.

Increasing cognitive load attenuates right arm swing in healthy human walking

NASA Astrophysics Data System (ADS)

Killeen, Tim; Easthope, Christopher S.; Filli, Linard; Lőrincz, Lilla; Schrafl-Altermatt, Miriam; Brugger, Peter; Linnebank, Michael; Curt, Armin; Zörner, Björn; Bolliger, Marc

2017-01-01

Human arm swing looks and feels highly automated, yet it is increasingly apparent that higher centres, including the cortex, are involved in many aspects of locomotor control. The addition of a cognitive task increases arm swing asymmetry during walking, but the characteristics and mechanism of this asymmetry are unclear. We hypothesized that this effect is lateralized and a Stroop word-colour naming task-primarily involving left hemisphere structures-would reduce right arm swing only. We recorded gait in 83 healthy subjects aged 18-80 walking normally on a treadmill and while performing a congruent and incongruent Stroop task. The primary measure of arm swing asymmetry-an index based on both three-dimensional wrist trajectories in which positive values indicate proportionally smaller movements on the right-increased significantly under dual-task conditions in those aged 40-59 and further still in the over-60s, driven by reduced right arm flexion. Right arm swing attenuation appears to be the norm in humans performing a locomotor-cognitive dual-task, confirming a prominent role of the brain in locomotor behaviour. Women under 60 are surprisingly resistant to this effect, revealing unexpected gender differences atop the hierarchical chain of locomotor control.

Balancing the Demands of Two Tasks: An Investigation of Cognitive-Motor Dual-Tasking in Relapsing Remitting Multiple Sclerosis.

PubMed

Butchard-MacDonald, Emma; Paul, Lorna; Evans, Jonathan J

2018-03-01

People with relapsing remitting multiple sclerosis (PwRRMS) suffer disproportionate decrements in gait under dual-task conditions, when walking and a cognitive task are combined. There has been much less investigation of the impact of cognitive demands on balance. This study investigated whether: (1) PwRRMS show disproportionate decrements in postural stability under dual-task conditions compared to healthy controls, and (2) dual-task decrements are associated with everyday dual-tasking difficulties. The impact of mood, fatigue, and disease severity on dual-tasking was also examined. A total of 34 PwRRMS and 34 matched controls completed cognitive (digit span) and balance (movement of center of pressure on Biosway on stable and unstable surfaces) tasks under single- and dual-task conditions. Everyday dual-tasking was measured using the Dual-Tasking Questionnaire. Mood was measured by the Hospital Anxiety & Depression Scale. Fatigue was measured via the Modified Fatigue Index Scale. No differences in age, gender, years of education, estimated pre-morbid IQ, or baseline digit span between groups. Compared with controls, PwRRMS showed significantly greater decrement in postural stability under dual-task conditions on an unstable surface (p=.007), but not a stable surface (p=.679). Balance decrement scores were not correlated with everyday dual-tasking difficulties or fatigue. Stable surface balance decrement scores were significantly associated with levels of anxiety (rho=0.527; p=.001) and depression (rho=0.451; p=.007). RRMS causes dual-tasking difficulties, impacting balance under challenging conditions, which may contribute to increased risk of gait difficulties and falls. The relationship between anxiety/depression and dual-task decrement suggests that emotional factors may be contributing to dual-task difficulties. (JINS, 2018, 24, 247-258).

A Comparison between young and old adults in their ability to rapidly sidestep during gait when attention is divided.

PubMed

Cho, Chiung-Yu; Gilchrist, Louise; White, Scott

2008-01-01

The incidence of falls among older adults is high and the risk factors are often complex in nature. Considerable research has been done in the area of age-related changes of balance in an attempt to better understand the increased risk of falls. Studies of cognitive changes, however, suggest that the elderly are less able to divide their attention between two or more activities. This inability to divide attention could explain the increased risks of falls in the elderly. To investigate the effects of divided attention, age and prior knowledge of movement path, on kinetic measures and the position of the sacral marker relative to the center of pressure (COP) when individuals perform a rapid sidestep during walking. 32 young and 32 old adults participated in this study. Subjects walked and took a sidestep without interrupting forward progression. An arithmetic task was performed during half of the walking trials with the sidestep direction preplanned or unknown. Peak lateral ground reaction force, mean distance between COP and sacrum, walking velocity, performance speed and accuracy of the cognitive task were measured. Both groups significantly decreased their mediolateral distance between the sacral marker and the COP in the dual-task trials (p = 0.04). Both groups significantly decreased their walking speed in the dual-task trials (p < 0.0001). Prior knowledge of the sidestep direction significantly affected the peak lateral ground reaction force and the sacral marker to COP distance but the differences were age-dependent. Young adults had a larger value in the unknown condition than in the preplanned condition (p < 0.0001). For the cognitive task, both groups decreased their performance speed (p < 0.0001) but maintained their performance accuracy as compared to the baseline data (p > 0.05). Our results revealed that old adults tended to be conservative, when facing the dual-task trials or unknown test condition. The fact that the older adults in the current study did not perform similarly to the younger adults suggests that they might have a fear of fall when facing a challenging balance task. (c) 2008 S. Karger AG, Basel.

Effects of Dual-Task Management and Resistance Training on Gait Performance in Older Individuals: A Randomized Controlled Trial.

PubMed

Wollesen, Bettina; Mattes, Klaus; Schulz, Sören; Bischoff, Laura L; Seydell, L; Bell, Jeffrey W; von Duvillard, Serge P

2017-01-01

Background: Dual-task (DT) training is a well-accepted modality for fall prevention in older adults. DT training should include task-managing strategies such as task switching or task prioritization to improve gait performance under DT conditions. Methods: We conducted a randomized controlled trial to evaluate a balance and task managing training (BDT group) in gait performance compared to a single task (ST) strength and resistance training and a control group, which received no training. A total of 78 older individuals (72.0 ± 4.9 years) participated in this study. The DT group performed task managing training incorporating balance and coordination tasks while the ST group performed resistance training only. Training consisted of 12 weekly sessions, 60 min each, for 12 weeks. We assessed the effects of ST and BDT training on walking performance under ST and DT conditions in independent living elderly adults. ST and DT walking (visual verbal Stroop task) were measured utilizing a treadmill at self-selected walking speed (mean for all groups: 4.4 ± 1 km h -1 ). Specific gait variables, cognitive performance, and fear of falling were compared between all groups. > Results: Training improved gait performance for step length ( p < 0.001) and gait-line (ST: p < 0.01; DT p < 0.05) in both training groups. The BDT training group showed greater improvements in step length ( p < 0.001) and gait-line ( p < 0.01) during DT walking but did not have changes in cognitive performance. Both interventions reduced fear of falling ( p < 0.05). Conclusion: Implementation of task management strategies into balance and strength training in our population revealed a promising modality to prevent falls in older individuals. Trial registration: German register of clinical trials DRKS00012382.

Virtual reality training to enhance behavior and cognitive function among children with attention-deficit/hyperactivity disorder: brief report.

PubMed

Shema-Shiratzky, Shirley; Brozgol, Marina; Cornejo-Thumm, Pablo; Geva-Dayan, Karen; Rotstein, Michael; Leitner, Yael; Hausdorff, Jeffrey M; Mirelman, Anat

2018-05-17

To examine the feasibility and efficacy of a combined motor-cognitive training using virtual reality to enhance behavior, cognitive function and dual-tasking in children with Attention-Deficit/Hyperactivity Disorder (ADHD). Fourteen non-medicated school-aged children with ADHD, received 18 training sessions during 6 weeks. Training included walking on a treadmill while negotiating virtual obstacles. Behavioral symptoms, cognition and gait were tested before and after the training and at 6-weeks follow-up. Based on parental report, there was a significant improvement in children's social problems and psychosomatic behavior after the training. Executive function and memory were improved post-training while attention was unchanged. Gait regularity significantly increased during dual-task walking. Long-term training effects were maintained in memory and executive function. Treadmill-training augmented with virtual-reality is feasible and may be an effective treatment to enhance behavior, cognitive function and dual-tasking in children with ADHD.

Effects of training and detraining on the static and dynamic balance in elderly fallers and non-fallers: a pilot study.

PubMed

Toulotte, Claire; Thevenon, Andre; Fabre, Claudine

2006-01-30

The aim of this study was to evaluate the effects of training based on static and dynamic balance in single and dual task conditions in order to analyse the effects of detraining on static and dynamic balance in healthy elderly fallers and non-fallers. A group of 16 subjects were trained: eight fallers aged 71.1 +/- 5.0 years and eight non-fallers aged 68.4 +/- 4.5 years. The subjects were evaluated 3 months before the training period, 2 days before the training period, 2 days after the end of the training period and 3 months after the training period. All subjects performed a unipedal test with eyes open and eyes closed. Gait parameters were analysed under single-task and dual motor-task conditions. This study demonstrated a loss of physical capacities over 3 months for stride time, single support time for fallers in both conditions. Physical training significantly improves static and dynamic balance under single and dual task conditions. Lastly, after 3 months of detraining, a loss of the physical training effects were measured for fallers and non-fallers on the different walking parameters in the two conditions and on the unipedal tests. The absence of stimulation before the trained period shows a negative effect of ageing on walking and falls whereas training permits an improvement in static balance and the pattern of walking under single and dual task conditions, which could be due to an increase in muscular strength and a better division of attention. On the other hand, 3 months of detraining inhibited the effects of training, which showed the speed of the decline caused by 'natural' ageing.

Does dual task training improve walking performance of older adults with concern of falling?

PubMed

Wollesen, B; Schulz, S; Seydell, L; Delbaere, K

2017-09-11

Older adults with concerns of falling show decrements of gait stability under single (ST) and dual task (DT) conditions. To compare the effects of a DT training integrating task managing strategies for independent living older adults with and without concern about falling (CoF) to a non-training control group on walking performance under ST and DT conditions. Single center parallel group single blind randomized controlled trial with group-based interventions (DT-managing balance training) compared to a control group (Ninety-five independent living older adults; 71.5 ± 5.2 years). A progressive DT training (12 sessions; 60 min each; 12 weeks) including task-managing strategies was compared to a non-training control group. group based intervention for independent living elderly in a gym. ST and DT walking (visual verbal Stroop task) were measured on a treadmill. Gait parameters (step length, step width, and gait line) and cognitive performance while walking were compared with a 2x2x2 Repeated Measures Analyses of Variance. Participants in the intervention group showed an increased step length under ST and DT conditions following the intervention, for both people with and without CoF compared to their respective control groups. Foot rolling movement and cognitive performance while walking however only improved in participants without CoF. The results showed that DT managing training can improve walking performance under ST and DT conditions in people with and without CoF. Additional treatment to directly address CoF, such as cognitive behavioural therapy, should be considered to further improve the cautious gait pattern (as evidenced by reduced foot rolling movements). The study was retrospectively registered in the German Clinical Trials Register (DRKS; Identification number DRKS00012382 , 11.05.2017).

Neural Correlates of Single- and Dual-Task Walking in the Real World

PubMed Central

Pizzamiglio, Sara; Naeem, Usman; Abdalla, Hassan; Turner, Duncan L.

2017-01-01

Recent developments in mobile brain-body imaging (MoBI) technologies have enabled studies of human locomotion where subjects are able to move freely in more ecologically valid scenarios. In this study, MoBI was employed to describe the behavioral and neurophysiological aspects of three different commonly occurring walking conditions in healthy adults. The experimental conditions were self-paced walking, walking while conversing with a friend and lastly walking while texting with a smartphone. We hypothesized that gait performance would decrease with increased cognitive demands and that condition-specific neural activation would involve condition-specific brain areas. Gait kinematics and high density electroencephalography (EEG) were recorded whilst walking around a university campus. Conditions with dual tasks were accompanied by decreased gait performance. Walking while conversing was associated with an increase of theta (θ) and beta (β) neural power in electrodes located over left-frontal and right parietal regions, whereas walking while texting was associated with a decrease of β neural power in a cluster of electrodes over the frontal-premotor and sensorimotor cortices when compared to walking whilst conversing. In conclusion, the behavioral “signatures” of common real-life activities performed outside the laboratory environment were accompanied by differing frequency-specific neural “biomarkers”. The current findings encourage the study of the neural biomarkers of disrupted gait control in neurologically impaired patients. PMID:28959199

Your brain on speed: cognitive performance of a spatial working memory task is not affected by walking speed

PubMed Central

Kline, Julia E.; Poggensee, Katherine; Ferris, Daniel P.

2014-01-01

When humans walk in everyday life, they typically perform a range of cognitive tasks while they are on the move. Past studies examining performance changes in dual cognitive-motor tasks during walking have produced a variety of results. These discrepancies may be related to the type of cognitive task chosen, differences in the walking speeds studied, or lack of controlling for walking speed. The goal of this study was to determine how young, healthy subjects performed a spatial working memory task over a range of walking speeds. We used high-density electroencephalography to determine if electrocortical activity mirrored changes in cognitive performance across speeds. Subjects stood (0.0 m/s) and walked (0.4, 0.8, 1.2, and 1.6 m/s) with and without performing a Brooks spatial working memory task. We hypothesized that performance of the spatial working memory task and the associated electrocortical activity would decrease significantly with walking speed. Across speeds, the spatial working memory task caused subjects to step more widely compared with walking without the task. This is typically a sign that humans are adapting their gait dynamics to increase gait stability. Several cortical areas exhibited power fluctuations time-locked to memory encoding during the cognitive task. In the somatosensory association cortex, alpha power increased prior to stimulus presentation and decreased during memory encoding. There were small significant reductions in theta power in the right superior parietal lobule and the posterior cingulate cortex around memory encoding. However, the subjects did not show a significant change in cognitive task performance or electrocortical activity with walking speed. These findings indicate that in young, healthy subjects walking speed does not affect performance of a spatial working memory task. These subjects can devote adequate cortical resources to spatial cognition when needed, regardless of walking speed. PMID:24847239

A Combined Cognitive Stimulation and Physical Exercise Programme (MINDVital) in Early Dementia: Differential Effects on Single- and Dual-Task Gait Performance.

PubMed

Tay, Laura; Lim, Wee Shiong; Chan, Mark; Ali, Noorhazlina; Chong, Mei Sian

2016-01-01

Gait disorders are common in early dementia, with particularly pronounced dual-task deficits, contributing to the increased fall risk and mobility decline associated with cognitive impairment. This study examines the effects of a combined cognitive stimulation and physical exercise programme (MINDVital) on gait performance under single- and dual-task conditions in older adults with mild dementia. Thirty-nine patients with early dementia participated in a multi-disciplinary rehabilitation programme comprising both physical exercise and cognitive stimulation. The programme was conducted in 8-week cycles with participants attending once weekly, and all participants completed 2 successive cycles. Cognitive, functional performance and behavioural symptoms were assessed at baseline and at the end of each 8-week cycle. Gait speed was examined under both single- (Timed Up and Go and 6-metre walk tests) and dual-task (animal category and serial counting) conditions. A random effects model was performed for the independent effect of MINDVital on the primary outcome variable of gait speed under dual-task conditions. The mean age of patients enroled in the rehabilitation programme was 79 ± 6.2 years; 25 (64.1%) had a diagnosis of Alzheimer's dementia, and 26 (66.7%) were receiving a cognitive enhancer therapy. There was a significant improvement in cognitive performance [random effects coefficient (standard error) = 0.90 (0.31), p = 0.003] and gait speed under both dual-task situations [animal category: random effects coefficient = 0.04 (0.02), p = 0.039; serial counting: random effects coefficient = 0.05 (0.02), p = 0.013], with reduced dual-task cost for gait speed [serial counting: random effects coefficient = -4.05 (2.35), p = 0.086] following successive MINDVital cycles. No significant improvement in single-task gait speed was observed. Improved cognitive performance over time was a significant determinant of changes in dual-task gait speed [random effects coefficients = 0.01 (0.005), p = 0.048, and 0.02 (0.005), p = 0.003 for category fluency and counting backwards, respectively]. A combined physical and cognitive rehabilitation programme leads to significant improvements in dual-task walking in early dementia, which may be contributed by improvement in cognitive performance, as single-task gait performance remained stable. © 2016 S. Karger AG, Basel.

Effects of dual task on turning ability in stroke survivors and older adults.

PubMed

Hollands, K L; Agnihotri, D; Tyson, S F

2014-09-01

Turning is an integral component of independent mobility in which stroke survivors frequently fall. This study sought to measure the effects of competing cognitive demands on the stepping patterns of stroke survivors, compared to healthy age-match adults, during turning as a putative mechanism for falls. Walking and turning (90°) was assessed under single (walking and turning alone) and dual task (subtracting serial 3s while walking and turning) conditions using an electronic, pressure-sensitive walkway. Dependent measures were time to turn, variability in time to turn, step length, step width and single support time during three steps of the turn. Turning ability in single and dual task conditions was compared between stroke survivors (n=17, mean ± SD: 59 ± 113 months post-stroke, 64 ± 10 years of age) and age-matched healthy counterparts (n=15). Both groups took longer, were more variable, tended to widen the second step and, crucially, increased single support time on the inside leg of the turn while turning and distracted. Increased single support time during turning may represent biomechanical mechanism, within stepping patterns of turning under distraction, for increased risk of falls for both stroke survivors and older adults. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Gait parameters are differently affected by concurrent smartphone-based activities with scaled levels of cognitive effort.

PubMed

Caramia, Carlotta; Bernabucci, Ivan; D'Anna, Carmen; De Marchis, Cristiano; Schmid, Maurizio

2017-01-01

The widespread and pervasive use of smartphones for sending messages, calling, and entertainment purposes, mainly among young adults, is often accompanied by the concurrent execution of other tasks. Recent studies have analyzed how texting, reading or calling while walking-in some specific conditions-might significantly influence gait parameters. The aim of this study is to examine the effect of different smartphone activities on walking, evaluating the variations of several gait parameters. 10 young healthy students (all smartphone proficient users) were instructed to text chat (with two different levels of cognitive load), call, surf on a social network or play with a math game while walking in a real-life outdoor setting. Each of these activities is characterized by a different cognitive load. Using an inertial measurement unit on the lower trunk, spatio-temporal gait parameters, together with regularity, symmetry and smoothness parameters, were extracted and grouped for comparison among normal walking and different dual task demands. An overall significant effect of task type on the aforementioned parameters group was observed. The alterations in gait parameters vary as a function of cognitive effort. In particular, stride frequency, step length and gait speed show a decrement, while step time increases as a function of cognitive effort. Smoothness, regularity and symmetry parameters are significantly altered for specific dual task conditions, mainly along the mediolateral direction. These results may lead to a better understanding of the possible risks related to walking and concurrent smartphone use.

Effects of a virtual reality and treadmill training on gait of subjects with multiple sclerosis: a pilot study.

PubMed

Peruzzi, Agnese; Cereatti, Andrea; Della Croce, Ugo; Mirelman, Anat

2016-01-01

Gait and cognitive deficits are common in multiple sclerosis (MS) and are negatively affected during dual-task walking. Treadmill (TM) training has been previously used to preserve locomotor activity in MS. Virtual reality (VR) engages the user in cognitive and motor activities simultaneously. A training combining TM and VR has been successfully adopted in several neurological diseases, but not in MS. This study aims at investigating the feasibility of a VR-based TM training program on gait of subjects with MS. Eight persons with relapsing-remitting MS were recruited to participate in a six-week VR-based TM training program. Gait analysis was performed both in single and dual task conditions. Clinical tests were used to assess walking endurance and obstacle negotiation. All the evaluations were performed before, immediately and one month after the training. Gait speed and stride length improved in dual task post-intervention and were retained at follow-up. An improved ability in negotiating obstacles was found across the evaluations. VR-based TM training program is feasible and safe for MS subjects with moderate disabilities and may positively affect gait under complex conditions, such as dual tasking and obstacle negotiation. Copyright © 2015. Published by Elsevier B.V.

Cell phones change the way we walk.

PubMed

Lamberg, Eric M; Muratori, Lisa M

2012-04-01

Cell phone use among pedestrians leads to increased cognitive distraction, reduced situation awareness and increases in unsafe behavior. Performing a dual-task, such as talking or texting with a cell phone while walking, may interfere with working memory and result in walking errors. At baseline, thirty-three participants visually located a target 8m ahead; then vision was occluded and they were instructed to walk to the remembered target. One week later participants were assigned to either walk, walk while talking on a cell phone, or walk while texting on a cell phone toward the target with vision occluded. Duration and final location of the heel were noted. Linear distance traveled, lateral angular deviation from the start line, and gait velocity were derived. Changes from baseline to testing were analyzed with paired t-tests. Participants engaged in cell phone use presented with significant reductions in gait velocity (texting: 33% reduction, p=0.01; talking: 16% reduction, p=0.02). Moreover, participants who were texting while walking demonstrated a 61% increase in lateral deviation (p=0.04) and 13% increase in linear distance traveled (p=0.03). These results suggest that the dual-task of walking while using a cell phone impacts executive function and working memory and influences gait to such a degree that it may compromise safety. Importantly, comparison of the two cell phone conditions demonstrates texting creates a significantly greater interference effect on walking than talking on a cell phone. Copyright © 2011 Elsevier B.V. All rights reserved.

Gray matter volume and dual-task gait performance in mild cognitive impairment.

PubMed

Doi, Takehiko; Blumen, Helena M; Verghese, Joe; Shimada, Hiroyuki; Makizako, Hyuma; Tsutsumimoto, Kota; Hotta, Ryo; Nakakubo, Sho; Suzuki, Takao

2017-06-01

Dual-task gait performance is impaired in older adults with mild cognitive impairment, but the brain substrates associated with dual-task gait performance are not well-established. The relationship between gray matter and gait speed under single-task and dual-task conditions (walking while counting backward) was examined in 560 seniors with mild cognitive impairment (non-amnestic mild cognitive impairment: n = 270; mean age = 72.4 yrs., 63.6 % women; amnestic mild cognitive impairment: n = 290; mean age = 73.4 yrs., 45.4 % women). Multivariate covariance-based analyses of magnetic resonance imaging data, adjusted for potential confounders including single-task gait speed, were performed to identify gray matter patterns associated with dual-task gait speed. There were no differences in gait speed or cognitive performance during dual-task gait between individuals with non-amnestic mild cognitive impairment and amnestic mild cognitive impairment. Overall, increased dual-task gait speed was associated with a gray matter pattern of increased volume in medial frontal gyrus, superior frontal gyrus, anterior cingulate, cingulate, precuneus, fusiform gyrus, middle occipital gyrus, inferior temporal gyrus and middle temporal gyrus. The relationship between dual-task gait speed and brain substrates also differed by mild cognitive impairment subtype. Our study revealed a pattern of gray matter regions associated with dual-task performance. Although dual-task gait performance was similar in amnestic and non-amnestic mild cognitive impairment, the gray matter patterns associated with dual-task gait performance differed by mild cognitive impairment subtype. These findings suggest that the brain substrates supporting dual-task gait performance in amnestic and non-amnestic subtypes are different, and consequently may respond differently to interventions, or require different interventions.

Gray matter volume and dual-task gait performance in mild cognitive impairment

PubMed Central

Blumen, Helena M.; Verghese, Joe; Shimada, Hiroyuki; Makizako, Hyuma; Tsutsumimoto, Kota; Hotta, Ryo; Nakakubo, Sho; Suzuki, Takao

2017-01-01

Dual-task gait performance is impaired in older adults with mild cognitive impairment, but the brain substrates associated with dual-task gait performance are not well-established. The relationship between gray matter and gait speed under single-task and dual-task conditions (walking while counting backward) was examined in 560 seniors with mild cognitive impairment (non-amnestic mild cognitive impairment: n = 270; mean age = 72.4 yrs., 63.6 % women; amnestic mild cognitive impairment: n = 290; mean age = 73.4 yrs., 45.4 % women). Multivariate covariance-based analyses of magnetic resonance imaging data, adjusted for potential confounders including single-task gait speed, were performed to identify gray matter patterns associated with dual-task gait speed. There were no differences in gait speed or cognitive performance during dual-task gait between individuals with non-amnestic mild cognitive impairment and amnestic mild cognitive impairment. Overall, increased dual-task gait speed was associated with a gray matter pattern of increased volume in medial frontal gyrus, superior frontal gyrus, anterior cingulate, cingulate, precuneus, fusiform gyrus, middle occipital gyrus, inferior temporal gyrus and middle temporal gyrus. The relationship between dual-task gait speed and brain substrates also differed by mild cognitive impairment subtype. Our study revealed a pattern of gray matter regions associated with dual-task performance. Although dual-task gait performance was similar in amnestic and non-amnestic mild cognitive impairment, the gray matter patterns associated with dual-task gait performance differed by mild cognitive impairment subtype. These findings suggest that the brain substrates supporting dual-task gait performance in amnestic and non-amnestic subtypes are different, and consequently may respond differently to interventions, or require different interventions. PMID:27392792

Neurofeedback training improves the dual-task performance ability in stroke patients.

PubMed

Lee, Young-Shin; Bae, Sea-Hyun; Lee, Sung-Hee; Kim, Kyung-Yoon

2015-05-01

Owing to the reduced capacity for information processing following a stroke, patients commonly present with difficulties in performing activities of daily living that combine two or more tasks. To address this problem, in the present study, we investigated the effects of neurofeedback training on the abilities of stroke patients to perform dual motor tasks. We randomly assigned 20 patients who had sustained a stroke within the preceding 6 months to either a pseudo-neurofeedback (n = 10) or neurofeedback (n = 10) group. Both groups participated in a general exercise intervention for 8 weeks, three times a week for 30 min per session, under the same conditions. An electrode was secured to the scalp over the region of the central lobe (Cz), in compliance with the International 10-20 System. The electrode was inactive for the pseudo-training group. Participants in the neurofeedback training group received the 30-min neurofeedback training per session for reinforcing the sensorimotor rhythm. Electroencephalographic activity of the two groups was compared. In addition, selected parameters of gait (velocity, cadence [step/min], stance phase [%], and foot pressure) were analyzed using a 10-m walk test, attention-demanding task, walk task and quantified by the SmartStep system. The neurofeedback group showed significantly improved the regulation of the sensorimotor rhythm (p < 0.001) and ability to execute dual tasks (p < 0.01). Significant improvements on selected gait parameters (velocity and cadence; p < 0.05) were also observed. We thus propose that the neurofeedback training is effective to improve the dual-task performance in stroke patients.

Relationship between strength, power and balance performance in seniors.

PubMed

Muehlbauer, Thomas; Besemer, Carmen; Wehrle, Anja; Gollhofer, Albert; Granacher, Urs

2012-01-01

Deficits in strength, power and balance represent important intrinsic risk factors for falls in seniors. The purpose of this study was to investigate the relationship between variables of lower extremity muscle strength/power and balance, assessed under various task conditions. Twenty-four healthy and physically active older adults (mean age: 70 ± 5 years) were tested for their isometric strength (i.e. maximal isometric force of the leg extensors) and muscle power (i.e. countermovement jump height and power) as well as for their steady-state (i.e. unperturbed standing, 10-meter walk), proactive (i.e. Timed Up & Go test, Functional Reach Test) and reactive (i.e. perturbed standing) balance. Balance tests were conducted under single (i.e. standing or walking alone) and dual task conditions (i.e. standing or walking plus cognitive and motor interference task). Significant positive correlations were found between measures of isometric strength and muscle power of the lower extremities (r values ranged between 0.608 and 0.720, p < 0.01). Hardly any significant associations were found between variables of strength, power and balance (i.e. no significant association in 20 out of 21 cases). Additionally, no significant correlations were found between measures of steady-state, proactive and reactive balance or balance tests performed under single and dual task conditions (all p > 0.05). The predominately nonsignificant correlations between different types of balance imply that balance performance is task specific in healthy and physically active seniors. Further, strength, power and balance as well as balance under single and dual task conditions seem to be independent of each other and may have to be tested and trained complementarily. Copyright © 2012 S. Karger AG, Basel.

Local dynamic stability and gait variability during attentional tasks in young adults.

PubMed

Magnani, Rina Márcia; Lehnen, Georgia Cristina; Rodrigues, Fábio Barbosa; de Sá E Souza, Gustavo Souto; de Oliveira Andrade, Adriano; Vieira, Marcus Fraga

2017-06-01

Cell phone use while walking may be a cognitive distraction and reduce visual and motor attention. Thus, the aim of this study was to verify the effects of attentional dual-tasks while using a cell phone in different conditions. Stability, regularity, and linear variability of trunk kinematics, and gait spatiotemporal parameters in young adults were measured. Twenty young subjects of both genders were asked to walk on a treadmill for 4min under the following conditions: (a) looking forward at a fixed target 2.5m away (walking); (b) talking on a cell phone with unilateral handling (talking); (c) texting messages on a cell phone with unilateral handling (texting); and (d) looking forward at the aforementioned target while listening to music without handling the phone (listening). Local dynamic stability measured in terms of the largest Lyapunov exponent decreased while handling a cell phone (talking and texting). Gait variability and regularity increased when talking on a cell phone, but no variable changed in the listening condition. Under all dual-task conditions, there were significant increases in stride width and its variability. We conclude that young adults who use a cell phone when walking adapt their gait pattern conservatively, which can be because of increased attentional demand during cell phone use. Copyright © 2017 Elsevier B.V. All rights reserved.

Wearable-Sensor-Based Classification Models of Faller Status in Older Adults.

PubMed

Howcroft, Jennifer; Lemaire, Edward D; Kofman, Jonathan

2016-01-01

Wearable sensors have potential for quantitative, gait-based, point-of-care fall risk assessment that can be easily and quickly implemented in clinical-care and older-adult living environments. This investigation generated models for wearable-sensor based fall-risk classification in older adults and identified the optimal sensor type, location, combination, and modelling method; for walking with and without a cognitive load task. A convenience sample of 100 older individuals (75.5 ± 6.7 years; 76 non-fallers, 24 fallers based on 6 month retrospective fall occurrence) walked 7.62 m under single-task and dual-task conditions while wearing pressure-sensing insoles and tri-axial accelerometers at the head, pelvis, and left and right shanks. Participants also completed the Activities-specific Balance Confidence scale, Community Health Activities Model Program for Seniors questionnaire, six minute walk test, and ranked their fear of falling. Fall risk classification models were assessed for all sensor combinations and three model types: multi-layer perceptron neural network, naïve Bayesian, and support vector machine. The best performing model was a multi-layer perceptron neural network with input parameters from pressure-sensing insoles and head, pelvis, and left shank accelerometers (accuracy = 84%, F1 score = 0.600, MCC score = 0.521). Head sensor-based models had the best performance of the single-sensor models for single-task gait assessment. Single-task gait assessment models outperformed models based on dual-task walking or clinical assessment data. Support vector machines and neural networks were the best modelling technique for fall risk classification. Fall risk classification models developed for point-of-care environments should be developed using support vector machines and neural networks, with a multi-sensor single-task gait assessment.

Improved Cognition While Cycling in Parkinson’s Disease Patients and Healthy Adults

PubMed Central

Hazamy, Audrey A.; Altmann, Lori J. P.; Stegemöller, Elizabeth; Bowers, Dawn; Lee, Hyo Keun; Wilson, Jonathan; Okun, Michael S.; Hass, Chris J.

2017-01-01

Persons with Parkinson’s disease (PD) are typically more susceptible than healthy adults to impaired performance when two tasks (dual task interference) are performed simultaneously. This limitation has by many experts been attributed to limitations in cognitive resources. Nearly all studies of dual task performance in PD employ walking or balance-based motor tasks, which are commonly impaired in PD. These tasks can be performed using a combination of one or two executive function tasks. The current study examined whether persons with PD would demonstrate greater dual task effects on cognition compared to healthy older adults (HOAs) during a concurrent cycling task. Participants with and without PD completed a battery of 12 cognitive tasks assessing visual and verbal processing in the following cognitive domains: speed of processing, controlled processing, working memory and executive function. Persons with PD exhibited impairments compared to healthy participants in select tasks (i.e., 0-Back, 2-Back and operation span). Further, both groups unexpectedly exhibited dual task facilitation of response times in visual tasks across cognitive domains, and improved verbal recall during an executive function task. Only one measure, 2-back, showed a speed-accuracy trade-off in the dual task. These results demonstrate that, when paired with a motor task in which they are not impaired, people with PD exhibit similar dual task effects on cognitive tasks as HOAs, even when these dual task effects are facilitative. More generally, these findings demonstrate that pairing cognitive tasks with cycling may actually improve cognitive performance which may have therapeutic relevance to cognitive decline associated with aging and PD pathology. PMID:28088064

Gait parameters are differently affected by concurrent smartphone-based activities with scaled levels of cognitive effort

PubMed Central

Bernabucci, Ivan; D'Anna, Carmen; De Marchis, Cristiano; Schmid, Maurizio

2017-01-01

The widespread and pervasive use of smartphones for sending messages, calling, and entertainment purposes, mainly among young adults, is often accompanied by the concurrent execution of other tasks. Recent studies have analyzed how texting, reading or calling while walking–in some specific conditions–might significantly influence gait parameters. The aim of this study is to examine the effect of different smartphone activities on walking, evaluating the variations of several gait parameters. 10 young healthy students (all smartphone proficient users) were instructed to text chat (with two different levels of cognitive load), call, surf on a social network or play with a math game while walking in a real-life outdoor setting. Each of these activities is characterized by a different cognitive load. Using an inertial measurement unit on the lower trunk, spatio-temporal gait parameters, together with regularity, symmetry and smoothness parameters, were extracted and grouped for comparison among normal walking and different dual task demands. An overall significant effect of task type on the aforementioned parameters group was observed. The alterations in gait parameters vary as a function of cognitive effort. In particular, stride frequency, step length and gait speed show a decrement, while step time increases as a function of cognitive effort. Smoothness, regularity and symmetry parameters are significantly altered for specific dual task conditions, mainly along the mediolateral direction. These results may lead to a better understanding of the possible risks related to walking and concurrent smartphone use. PMID:29023456

Improving Sensitivity to Detect Mild Cognitive Impairment: Cognitive Load Dual-Task Gait Speed Assessment.

PubMed

MacAulay, Rebecca K; Wagner, Mark T; Szeles, Dana; Milano, Nicholas J

2017-07-01

Longitudinal research indicates that cognitive load dual-task gait assessment is predictive of cognitive decline and thus might provide a sensitive measure to screen for mild cognitive impairment (MCI). However, research among older adults being clinically evaluated for cognitive concerns, a defining feature of MCI, is lacking. The present study investigated the effect of performing a cognitive task on normal walking speed in patients presenting to a memory clinic with cognitive complaints. Sixty-one patients with a mean age of 68 years underwent comprehensive neuropsychological testing, clinical interview, and gait speed (simple- and dual-task conditions) assessments. Thirty-four of the 61 patients met criteria for MCI. Repeated measure analyses of covariance revealed that greater age and MCI both significantly associated with slower gait speed, ps<.05. Follow-up analysis indicated that the MCI group had significantly slower dual-task gait speed but did not differ in simple-gait speed. Multivariate linear regression across groups found that executive attention performance accounted for 27.4% of the variance in dual-task gait speed beyond relevant demographic and health risk factors. The present study increases the external validity of dual-task gait assessment of MCI. Differences in dual-task gait speed appears to be largely attributable to executive attention processes. These findings have clinical implications as they demonstrate expected patterns of gait-brain behavior relationships in response to a cognitive dual task within a clinically representative population. Cognitive load dual-task gait assessment may provide a cost efficient and sensitive measure to detect older adults at high risk of a dementia disorder. (JINS, 2017, 23, 493-501).

The Effects of Combining Videogame Dancing and Pelvic Floor Training to Improve Dual-Task Gait and Cognition in Women with Mixed-Urinary Incontinence.

PubMed

Fraser, Sarah A; Elliott, Valerie; de Bruin, Eling D; Bherer, Louis; Dumoulin, Chantal

2014-06-01

Many women over 65 years of age suffer from mixed urinary incontinence (MUI) and executive function (EF) deficits. Both incontinence and EF declines increase fall risk. The current study assessed EF and dual-task gait after a multicomponent intervention that combined pelvic floor muscle (PFM) training and videogame dancing (VGD). Baseline (Pre1), pretraining (Pre2), and post-training (Post) neuropsychological and dual-task gait assessments were completed by 23 women (mean age, 70.4 years) with MUI. During the dual-task, participants walked and performed an auditory n-back task. From Pre2 to Post, all women completed 12 weeks of combined PFM and VGD training. After training (Pre2 to Post), the number of errors in the Inhibition/Switch Stroop condition decreased significantly, the Trail Making Test difference score improved marginally, and the number of n-back errors during dual-task gait significantly decreased. A subgroup analysis based on continence improvements (pad test) revealed that only those subjects who improved in the pad test had significantly reduced numbers of n-back errors during dual-task gait. The results of this study suggest that a multicomponent intervention can improve EFs and the dual-task gait of older women with MUI. Future research is needed to determine if the training-induced improvements in these factors reduce fall risk.

Parkinsonian gait improves with bilateral subthalamic nucleus deep brain stimulation during cognitive multi-tasking.

PubMed

Chenji, Gaurav; Wright, Melissa L; Chou, Kelvin L; Seidler, Rachael D; Patil, Parag G

2017-05-01

Gait impairment in Parkinson's disease reduces mobility and increases fall risk, particularly during cognitive multi-tasking. Studies suggest that bilateral subthalamic deep brain stimulation, a common surgical therapy, degrades motor performance under cognitive dual-task conditions, compared to unilateral stimulation. To measure the impact of bilateral versus unilateral subthalamic deep brain stimulation on walking kinematics with and without cognitive dual-tasking. Gait kinematics of seventeen patients with advanced Parkinson's disease who had undergone bilateral subthalamic deep brain stimulation were examined off medication under three stimulation states (bilateral, unilateral left, unilateral right) with and without a cognitive challenge, using an instrumented walkway system. Consistent with earlier studies, gait performance declined for all six measured parameters under cognitive dual-task conditions, independent of stimulation state. However, bilateral stimulation produced greater improvements in step length and double-limb support time than unilateral stimulation, and achieved similar performance for other gait parameters. Contrary to expectations from earlier studies of dual-task motor performance, bilateral subthalamic deep brain stimulation may assist in maintaining temporal and spatial gait performance under cognitive dual-task conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Effect of a Six-Month Dancing Program on Motor-Cognitive Dual-Task Performance in Older Adults.

PubMed

Hamacher, Dennis; Hamacher, Daniel; Rehfeld, Kathrin; Hökelmann, Anita; Schega, Lutz

2015-10-01

Dancing is a complex sensorimotor activity involving physical and mental elements which have positive effects on cognitive functions and motor control. The present randomized controlled trial aims to analyze the effects of a dancing program on the performance on a motor-cognitive dual task. Data of 35 older adults, who were assigned to a dancing group or a health-related exercise group, are presented in the study. In pretest and posttest, we assessed cognitive performance and variability of minimum foot clearance, stride time, and stride length while walking. Regarding the cognitive performance and the stride-to-stride variability of minimum foot clearance, interaction effects have been found, indicating that dancing lowers gait variability to a higher extent than conventional health-related exercise. The data show that dancing improves minimum foot clearance variability and cognitive performance in a dual-task situation. Multi-task exercises (like dancing) might be a powerful tool to improve motor-cognitive dual-task performance.

Single- and Dual-Task Balance Training Are Equally Effective in Youth

PubMed Central

Lüder, Benjamin; Kiss, Rainer; Granacher, Urs

2018-01-01

Due to maturation of the postural control system and secular declines in motor performance, adolescents experience deficits in postural control during standing and walking while concurrently performing cognitive interference tasks. Thus, adequately designed balance training programs may help to counteract these deficits. While the general effectiveness of youth balance training is well-documented, there is hardly any information available on the specific effects of single-task (ST) versus dual-task (DT) balance training. Therefore, the objectives of this study were (i) to examine static/dynamic balance performance under ST and DT conditions in adolescents and (ii) to study the effects of ST versus DT balance training on static/dynamic balance under ST and DT conditions in adolescents. Twenty-eight healthy girls and boys aged 12–13 years were randomly assigned to either 8 weeks of ST or DT balance training. Before and after training, postural sway and spatio-temporal gait parameters were registered under ST (standing/walking only) and DT conditions (standing/walking while concurrently performing an arithmetic task). At baseline, significantly slower gait speed (p < 0.001, d = 5.1), shorter stride length (p < 0.001, d = 4.8), and longer stride time (p < 0.001, d = 3.8) were found for DT compared to ST walking but not standing. Training resulted in significant pre–post decreases in DT costs for gait velocity (p < 0.001, d = 3.1), stride length (-45%, p < 0.001, d = 2.4), and stride time (-44%, p < 0.01, d = 1.9). Training did not induce any significant changes (p > 0.05, d = 0–0.1) in DT costs for all parameters of secondary task performance during standing and walking. Training produced significant pre–post increases (p = 0.001; d = 1.47) in secondary task performance while sitting. The observed increase was significantly greater for the ST training group (p = 0.04; d = 0.81). For standing, no significant changes were found over time irrespective of the experimental group. We conclude that adolescents showed impaired DT compared to ST walking but not standing. ST and DT balance training resulted in significant and similar changes in DT costs during walking. Thus, there appears to be no preference for either ST or DT balance training in adolescents. PMID:29928248

Single- and Dual-Task Balance Training Are Equally Effective in Youth.

PubMed

Lüder, Benjamin; Kiss, Rainer; Granacher, Urs

2018-01-01

Due to maturation of the postural control system and secular declines in motor performance, adolescents experience deficits in postural control during standing and walking while concurrently performing cognitive interference tasks. Thus, adequately designed balance training programs may help to counteract these deficits. While the general effectiveness of youth balance training is well-documented, there is hardly any information available on the specific effects of single-task (ST) versus dual-task (DT) balance training. Therefore, the objectives of this study were (i) to examine static/dynamic balance performance under ST and DT conditions in adolescents and (ii) to study the effects of ST versus DT balance training on static/dynamic balance under ST and DT conditions in adolescents. Twenty-eight healthy girls and boys aged 12-13 years were randomly assigned to either 8 weeks of ST or DT balance training. Before and after training, postural sway and spatio-temporal gait parameters were registered under ST (standing/walking only) and DT conditions (standing/walking while concurrently performing an arithmetic task). At baseline, significantly slower gait speed ( p < 0.001, d = 5.1), shorter stride length ( p < 0.001, d = 4.8), and longer stride time ( p < 0.001, d = 3.8) were found for DT compared to ST walking but not standing. Training resulted in significant pre-post decreases in DT costs for gait velocity ( p < 0.001, d = 3.1), stride length (-45%, p < 0.001, d = 2.4), and stride time (-44%, p < 0.01, d = 1.9). Training did not induce any significant changes ( p > 0.05, d = 0-0.1) in DT costs for all parameters of secondary task performance during standing and walking. Training produced significant pre-post increases ( p = 0.001; d = 1.47) in secondary task performance while sitting. The observed increase was significantly greater for the ST training group ( p = 0.04; d = 0.81). For standing, no significant changes were found over time irrespective of the experimental group. We conclude that adolescents showed impaired DT compared to ST walking but not standing. ST and DT balance training resulted in significant and similar changes in DT costs during walking. Thus, there appears to be no preference for either ST or DT balance training in adolescents.

Effects of Tai Chi intervention on dual-task ability in older adults: a pilot study.

PubMed

Hall, Courtney D; Miszko, Tanya; Wolf, Steven L

2009-03-01

To determine if a 12-week program of Tai Chi that has been shown to reduce falls incidence in older adults would improve the ability to allocate attention to balance under dual-task conditions. Pre-/posttest experimental research design. Movement studies research laboratory. Community dwelling older adults (N=15; range, 62-85y) participated in either Tai Chi training or health education classes (controls) for 12 weeks. Participants in the Tai Chi group attended a twice-weekly, 1.5-hour class taught by an experienced instructor. The control group attended a biweekly, 1-hour class for lectures on health-related topics. Two cognitive tasks (responding to auditory or visual stimulus as quickly as possible) were performed concurrently while maintaining static balance during the Sensory Organization Test (SOT) and while avoiding obstacles while walking. The percent change in performance relative to the single-task condition was calculated and defined as the dual-task cost. The dual-task cost was calculated for both the postural and cognitive measures. There was no improvement in the performance of postural stability or cognitive task under dual-task conditions for the SOT for Tai Chi versus controls. There was no improvement in avoiding obstacles under dual-task conditions for Tai Chi versus controls. Contrary to our hypothesis, the findings of this study did not support a benefit of Tai Chi on the ability to allocate attention to balance under dual-task conditions.

Arm swing as a potential new prodromal marker of Parkinson's disease.

PubMed

Mirelman, Anat; Bernad-Elazari, Hagar; Thaler, Avner; Giladi-Yacobi, Eytan; Gurevich, Tanya; Gana-Weisz, Mali; Saunders-Pullman, Rachel; Raymond, Deborah; Doan, Nancy; Bressman, Susan B; Marder, Karen S; Alcalay, Roy N; Rao, Ashwini K; Berg, Daniela; Brockmann, Kathrin; Aasly, Jan; Waro, Bjørg Johanne; Tolosa, Eduardo; Vilas, Dolores; Pont-Sunyer, Claustre; Orr-Urtreger, Avi; Hausdorff, Jeffrey M; Giladi, Nir

2016-10-01

Reduced arm swing is a well-known clinical feature of Parkinson's disease (PD), often observed early in the course of the disease. We hypothesized that subtle changes in arm swing and axial rotation may also be detectable in the prodromal phase. The purpose of this study was to evaluate the relationship between the LRRK2-G2019S mutation, arm swing, and axial rotation in healthy nonmanifesting carriers and noncarriers of the G2019S mutation and in patients with PD. A total of 380 participants (186 healthy nonmanifesting controls and 194 PD patients) from 6 clinical sites underwent gait analysis while wearing synchronized 3-axis body-fixed sensors on the lower back and bilateral wrists. Participants walked for 1 minute under the following 2 conditions: (1) usual walking and (2) dual-task walking. Arm swing amplitudes, asymmetry, variability, and smoothness were calculated for both arms along with measures of axial rotation. A total of 122 nonmanifesting participants and 67 PD patients were carriers of the G2019S mutation. Nonmanifesting mutation carriers walked with greater arm swing asymmetry and variability and lower axial rotation smoothness under the dual task condition when compared with noncarriers (P < .04). In the nonmanifesting mutation carriers, arm swing asymmetry was associated with gait variability under dual task (P = .003). PD carriers showed greater asymmetry and variability of movement than PD noncarriers, even after controlling for disease severity (P < .009). The G2019S mutation is associated with increased asymmetry and variability among nonmanifesting participants and patients with PD. Prospective studies should determine if arm swing asymmetry and axial rotation smoothness may be used as motor markers of prodromal PD. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

Effects of Physical-Cognitive Dual Task Training on Executive Function and Gait Performance in Older Adults: A Randomized Controlled Trial

PubMed Central

Falbo, S.; Condello, G.; Capranica, L.; Forte, R.

2016-01-01

Physical and cognitive training seem to counteract age-related decline in physical and mental function. Recently, the possibility of integrating cognitive demands into physical training has attracted attention. The purpose of this study was to evaluate the effects of twelve weeks of designed physical-cognitive training on executive cognitive function and gait performance in older adults. Thirty-six healthy, active individuals aged 72.30 ± 5.84 years were assigned to two types of physical training with major focus on physical single task (ST) training (n = 16) and physical-cognitive dual task (DT) training (n = 20), respectively. They were tested before and after the intervention for executive function (inhibition, working memory) through Random Number Generation and for gait (walking with/without negotiating hurdles) under both single and dual task (ST, DT) conditions. Gait performance improved in both groups, while inhibitory performance decreased after exercise training with ST focus but tended to increase after training with physical-cognitive DT focus. Changes in inhibition performance were correlated with changes in DT walking performance with group differences as a function of motor task complexity (with/without hurdling). The study supports the effectiveness of group exercise classes for older individuals to improve gait performance, with physical-cognitive DT training selectively counteracting the age-related decline in a core executive function essential for daily living. PMID:28053985

Effects of Physical-Cognitive Dual Task Training on Executive Function and Gait Performance in Older Adults: A Randomized Controlled Trial.

PubMed

Falbo, S; Condello, G; Capranica, L; Forte, R; Pesce, C

2016-01-01

Physical and cognitive training seem to counteract age-related decline in physical and mental function. Recently, the possibility of integrating cognitive demands into physical training has attracted attention. The purpose of this study was to evaluate the effects of twelve weeks of designed physical-cognitive training on executive cognitive function and gait performance in older adults. Thirty-six healthy, active individuals aged 72.30 ± 5.84 years were assigned to two types of physical training with major focus on physical single task (ST) training ( n = 16) and physical-cognitive dual task (DT) training ( n = 20), respectively. They were tested before and after the intervention for executive function (inhibition, working memory) through Random Number Generation and for gait (walking with/without negotiating hurdles) under both single and dual task (ST, DT) conditions. Gait performance improved in both groups, while inhibitory performance decreased after exercise training with ST focus but tended to increase after training with physical-cognitive DT focus. Changes in inhibition performance were correlated with changes in DT walking performance with group differences as a function of motor task complexity (with/without hurdling). The study supports the effectiveness of group exercise classes for older individuals to improve gait performance, with physical-cognitive DT training selectively counteracting the age-related decline in a core executive function essential for daily living.

Effects of fear of falling and activity restriction on normal and dual task walking in community dwelling older adults.

PubMed

Donoghue, Orna A; Cronin, Hilary; Savva, George M; O'Regan, Claire; Kenny, Rose Anne

2013-05-01

Fear of falling (FOF) is associated with poor physical and psychosocial health and can have debilitating consequences especially when it leads to activity restriction. This study examined whether normal and dual task gait disruptions were independently associated with FOF and activity restriction or if they were fully explained by impaired health status. Data was obtained from The Irish Longitudinal Study on Ageing (TILDA). Community dwelling adults ≥65 years, with a Mini-Mental State Examination score ≥18 and who completed a gait assessment (n=1307) were divided into three groups: no FOF, FOF but no activity restriction (FOF-NAR), FOF with activity restriction (FOF-AR). Physical, psychosocial and cognitive measures were obtained and gait characteristics were assessed using a GAITRite(®) mat during normal and dual task (cognitive) walking. After adjusting for sociodemographics, physical, mental and cognitive health, FOF was associated with reduced gait speed and stride length and increased double support phase and step width in normal and dual task conditions; these changes were most pronounced in those who restrict activities as a result of FOF. These gait changes may be associated with an increased fall risk, however some changes especially increased step width may also reflect positive, compensatory adaptations to FOF. The results also highlight the importance of treating underlying health impairments and preventing the transition from FOF to activity restriction. Copyright © 2012 Elsevier B.V. All rights reserved.

Freezing of Gait in Parkinson's Disease: An Overload Problem?

PubMed

Beck, Eric N; Ehgoetz Martens, Kaylena A; Almeida, Quincy J

2015-01-01

Freezing of gait (FOG) is arguably the most severe symptom associated with Parkinson's disease (PD), and often occurs while performing dual tasks or approaching narrowed and cluttered spaces. While it is well known that visual cues alleviate FOG, it is not clear if this effect may be the result of cognitive or sensorimotor mechanisms. Nevertheless, the role of vision may be a critical link that might allow us to disentangle this question. Gaze behaviour has yet to be carefully investigated while freezers approach narrow spaces, thus the overall objective of this study was to explore the interaction between cognitive and sensory-perceptual influences on FOG. In experiment #1, if cognitive load is the underlying factor leading to FOG, then one might expect that a dual-task would elicit FOG episodes even in the presence of visual cues, since the load on attention would interfere with utilization of visual cues. Alternatively, if visual cues alleviate gait despite performance of a dual-task, then it may be more probable that sensory mechanisms are at play. In compliment to this, the aim of experiment#2 was to further challenge the sensory systems, by removing vision of the lower-limbs and thereby forcing participants to rely on other forms of sensory feedback rather than vision while walking toward the narrow space. Spatiotemporal aspects of gait, percentage of gaze fixation frequency and duration, as well as skin conductance levels were measured in freezers and non-freezers across both experiments. Results from experiment#1 indicated that although freezers and non-freezers both walked with worse gait while performing the dual-task, in freezers, gait was relieved by visual cues regardless of whether the cognitive demands of the dual-task were present. At baseline and while dual-tasking, freezers demonstrated a gaze behaviour that neglected the doorway and instead focused primarily on the pathway, a strategy that non-freezers adopted only when performing the dual-task. Interestingly, with the combination of visual cues and dual-task, freezers increased the frequency and duration of fixations toward the doorway, compared to non-freezers. These results suggest that although increasing demand on attention does significantly deteriorate gait in freezers, an increase in cognitive demand is not exclusively responsible for freezing (since visual cues were able to overcome any interference elicited by the dual-task). When vision of the lower limbs was removed in experiment#2, only the freezers' gait was affected. However, when visual cues were present, freezers' gait improved regardless of the dual-task. This gait behaviour was accompanied by greater amount of time spent looking at the visual cues irrespective of the dual-task. Since removing vision of the lower-limbs hindered gait even under low attentional demand, restricted sensory feedback may be an important factor to the mechanisms underlying FOG.

Freezing of Gait in Parkinson’s Disease: An Overload Problem?

PubMed Central

Beck, Eric N.; Ehgoetz Martens, Kaylena A.; Almeida, Quincy J.

2015-01-01

Freezing of gait (FOG) is arguably the most severe symptom associated with Parkinson’s disease (PD), and often occurs while performing dual tasks or approaching narrowed and cluttered spaces. While it is well known that visual cues alleviate FOG, it is not clear if this effect may be the result of cognitive or sensorimotor mechanisms. Nevertheless, the role of vision may be a critical link that might allow us to disentangle this question. Gaze behaviour has yet to be carefully investigated while freezers approach narrow spaces, thus the overall objective of this study was to explore the interaction between cognitive and sensory-perceptual influences on FOG. In experiment #1, if cognitive load is the underlying factor leading to FOG, then one might expect that a dual-task would elicit FOG episodes even in the presence of visual cues, since the load on attention would interfere with utilization of visual cues. Alternatively, if visual cues alleviate gait despite performance of a dual-task, then it may be more probable that sensory mechanisms are at play. In compliment to this, the aim of experiment#2 was to further challenge the sensory systems, by removing vision of the lower-limbs and thereby forcing participants to rely on other forms of sensory feedback rather than vision while walking toward the narrow space. Spatiotemporal aspects of gait, percentage of gaze fixation frequency and duration, as well as skin conductance levels were measured in freezers and non-freezers across both experiments. Results from experiment#1 indicated that although freezers and non-freezers both walked with worse gait while performing the dual-task, in freezers, gait was relieved by visual cues regardless of whether the cognitive demands of the dual-task were present. At baseline and while dual-tasking, freezers demonstrated a gaze behaviour that neglected the doorway and instead focused primarily on the pathway, a strategy that non-freezers adopted only when performing the dual-task. Interestingly, with the combination of visual cues and dual-task, freezers increased the frequency and duration of fixations toward the doorway, compared to non-freezers. These results suggest that although increasing demand on attention does significantly deteriorate gait in freezers, an increase in cognitive demand is not exclusively responsible for freezing (since visual cues were able to overcome any interference elicited by the dual-task). When vision of the lower limbs was removed in experiment#2, only the freezers’ gait was affected. However, when visual cues were present, freezers’ gait improved regardless of the dual-task. This gait behaviour was accompanied by greater amount of time spent looking at the visual cues irrespective of the dual-task. Since removing vision of the lower-limbs hindered gait even under low attentional demand, restricted sensory feedback may be an important factor to the mechanisms underlying FOG. PMID:26678262

Are gamers better crossers? An examination of action video game experience and dual task effects in a simulated street crossing task.

PubMed

Gaspar, John G; Neider, Mark B; Crowell, James A; Lutz, Aubrey; Kaczmarski, Henry; Kramer, Arthur F

2014-05-01

A high-fidelity street crossing simulator was used to test the hypothesis that experienced action video game players are less vulnerable than non-gamers to dual task costs in complex tasks. Previous research has shown that action video game players outperform nonplayers on many single task measures of perception and attention. It is unclear, however, whether action video game players outperform nonplayers in complex, divided attention tasks. Experienced action video game players and nongamers completed a street crossing task in a high-fidelity simulator. Participants walked on a manual treadmill to cross the street. During some crossings, a cognitively demanding working memory task was added. Dividing attention resulted in more collisions and increased decision making time. Of importance, these dual task costs were equivalent for the action video game players and the nongamers. These results suggest that action video game players are equally susceptible to the costs of dividing attention in a complex task. Perceptual and attentional benefits associated with action video game experience may not translate to performance benefits in complex, real-world tasks.

A Virtual Reality avatar interaction (VRai) platform to assess residual executive dysfunction in active military personnel with previous mild traumatic brain injury: proof of concept.

PubMed

Robitaille, Nicolas; Jackson, Philip L; Hébert, Luc J; Mercier, Catherine; Bouyer, Laurent J; Fecteau, Shirley; Richards, Carol L; McFadyen, Bradford J

2017-10-01

This proof of concept study tested the ability of a dual task walking protocol using a recently developed avatar-based virtual reality (VR) platform to detect differences between military personnel post mild traumatic brain injury (mTBI) and healthy controls. The VR platform coordinated motion capture, an interaction and rendering system, and a projection system to present first (participant-controlled) and third person avatars within the context of a specific military patrol scene. A divided attention task was also added. A healthy control group was compared to a group with previous mTBI (both groups comprised of six military personnel) and a repeated measures ANOVA tested for differences between conditions and groups based on recognition errors, walking speed and fluidity and obstacle clearance. The VR platform was well tolerated by both groups. Walking fluidity was degraded for the control group within the more complex navigational dual tasking involving avatars, and appeared greatest in the dual tasking with the interacting avatar. This navigational behaviour was not seen in the mTBI group. The present findings show proof of concept for using avatars, particularly more interactive avatars, to expose differences in executive functioning when applying context-specific protocols (here for the military). Implications for rehabilitation Virtual reality provides a means to control context-specific factors for assessment and intervention. Adding human interaction and agency through avatars increases the ecologic nature of the virtual environment. Avatars in the present application of the Virtual Reality avatar interaction platform appear to provide a better ability to reveal differences between trained, military personal with and without mTBI.

Effect of aquatic dual-task training on balance and gait in stroke patients

PubMed Central

Kim, Kyoung; Lee, Dong-Kyu; Kim, Eun-Kyung

2016-01-01

[Purpose] The purpose of this study was to determine the effect of aquatic dual-task training on balance and gait in stroke patients. [Subjects and Methods] Twenty stroke patients were divided into the experimental (n=10) and control (n=10) groups. Both groups underwent neurodevelopmental treatment. The experimental group additionally underwent aquatic dual-task training for 30 minutes a day, 5 days a week, for 6 weeks. Balance was measured using the Berg balance scale, Five Times Sit-to Stand Test, and Functional Reach Test. Gait was measured using the 10-Meter Walk Test, Timed Up and Go Test, and Functional Gait Assessment. [Results] For intragroup comparison, the experimental group showed a significant change after the experiment in all balance and gait assessment tests. For intergroup comparison, the experimental group showed relatively more significant change after the experiment in all balance and gait assessment tests. [Conclusion] Our results showed that aquatic dual-task training has a positive effect on balance and gait in stroke patients. PMID:27512261

Effect of aquatic dual-task training on balance and gait in stroke patients.

PubMed

Kim, Kyoung; Lee, Dong-Kyu; Kim, Eun-Kyung

2016-07-01

[Purpose] The purpose of this study was to determine the effect of aquatic dual-task training on balance and gait in stroke patients. [Subjects and Methods] Twenty stroke patients were divided into the experimental (n=10) and control (n=10) groups. Both groups underwent neurodevelopmental treatment. The experimental group additionally underwent aquatic dual-task training for 30 minutes a day, 5 days a week, for 6 weeks. Balance was measured using the Berg balance scale, Five Times Sit-to Stand Test, and Functional Reach Test. Gait was measured using the 10-Meter Walk Test, Timed Up and Go Test, and Functional Gait Assessment. [Results] For intragroup comparison, the experimental group showed a significant change after the experiment in all balance and gait assessment tests. For intergroup comparison, the experimental group showed relatively more significant change after the experiment in all balance and gait assessment tests. [Conclusion] Our results showed that aquatic dual-task training has a positive effect on balance and gait in stroke patients.

Gait profile score and movement analysis profile in patients with Parkinson's disease during concurrent cognitive load

PubMed Central

Speciali, Danielli S.; Oliveira, Elaine M.; Cardoso, Jefferson R.; Correa, João C. F.; Baker, Richard; Lucareli, Paulo R. G.

2014-01-01

Background: Gait disorders are common in individuals with Parkinson's Disease (PD) and the concurrent performance of motor and cognitive tasks can have marked effects on gait. The Gait Profile Score (GPS) and the Movement Analysis Profile (MAP) were developed in order to summarize the data of kinematics and facilitate understanding of the results of gait analysis. Objective: To investigate the effectiveness of the GPS and MAP in the quantification of changes in gait during a concurrent cognitive load while walking in adults with and without PD. Method: Fourteen patients with idiopathic PD and nine healthy subjects participated in the study. All subjects performed single and dual walking tasks. The GPS/MAP was computed from three-dimensional gait analysis data. Results: Differences were found between tasks for GPS (P<0.05) and Gait Variable Score (GVS) (pelvic rotation, knee flexion-extension and ankle dorsiflexion-plantarflexion) (P<0.05) in the PD group. An interaction between task and group was observed for GPS (P<0.01) for the right side (Cohen's ¯d=0.99), left side (Cohen's ¯d=0.91), and overall (Cohen's ¯d=0.88). No interaction was observed only for hip internal-external rotation and foot internal-external progression GVS variables in the PD group. Conclusions: The results showed gait impairment during the dual task and suggest that GPS/MAP may be used to evaluate the effects of concurrent cognitive load while walking in patients with PD. PMID:25054382

Prefrontal over-activation during walking in people with mobility deficits: Interpretation and functional implications.

PubMed

Hawkins, Kelly A; Fox, Emily J; Daly, Janis J; Rose, Dorian K; Christou, Evangelos A; McGuirk, Theresa E; Otzel, Dana M; Butera, Katie A; Chatterjee, Sudeshna A; Clark, David J

2018-06-01

Control of walking by the central nervous system includes contributions from executive control mechanisms, such as attention and motor planning resources. Executive control of walking can be estimated objectively by recording prefrontal cortical activity using functional near infrared spectroscopy (fNIRS). The primary objective of this study was to investigate group differences in prefrontal/executive control of walking among young adults, older adults, and adults post-stroke. Also assessed was the extent to which walking-related prefrontal activity fits existing cognitive frameworks of prefrontal over-activation. Participants included 24 adults post-stroke with moderate to severe walking deficits, 15 older adults with mild gait deficits, and 9 young healthy adults. Executive control of walking was quantified as oxygenated hemoglobin concentration in the prefrontal cortex measured by fNIRS. Three walking tasks were assessed: typical walking, walking over obstacles, and walking while performing a verbal fluency task. Walking performance was assessed by walking speed. There was a significant effect of group for prefrontal activity (p < 0.001) during typical and obstacles walking tasks, with young adults exhibiting the lowest level of prefrontal activity, followed by older adults, and then adults post-stroke. In young adults the prefrontal activity during typical walking was much lower than for the verbal fluency dual-task, suggesting substantial remaining prefrontal resources during typical walking. However, in older and post-stroke adults these remaining resources were significantly less (p < 0.01). Cumulatively, these results are consistent with prefrontal over-activation in the older and stroke groups, which was accompanied by a steeper drop in walking speed as task complexity increased to include obstacles (p < 0.05). There is a heightened use of prefrontal/executive control resources in older adults and post-stroke adults during walking. The level of prefrontal resource utilization, particularly during complex walking tasks like obstacle crossing, may approach the ceiling of available resources for people who have walking deficits. Prior cognitive research has revealed that prefrontal over-activation combined with limited prefrontal resources can lead to poor cognitive performance. The present study suggests a similar situation influences walking performance. Future research should further investigate the extent to which prefrontal over-activation during walking is linked to adverse mobility outcomes. Published by Elsevier B.V.

Increased Cognitive Load Leads to Impaired Mobility Decisions in Seniors at Risk for Falls

PubMed Central

Nagamatsu, Lindsay S.; Voss, Michelle; Neider, Mark B.; Gaspar, John G.; Handy, Todd C.; Kramer, Arthur F.; Liu-Ambrose, Teresa Y. L.

2011-01-01

Successful mobility requires appropriate decision-making. Seniors with reduced executive functioning— such as senior fallers—may be prone to poor mobility judgments, especially under dual-task conditions. We classified participants as “At-Risk” and “Not-At-Risk” for falls using a validated physiological falls-risk assessment. Dual-task performance was assessed in a virtual reality environment where participants crossed a simulated street by walking on a manual treadmill while listening to music or conversing on a phone. Those “At-Risk” experienced more collisions with oncoming cars and had longer crossing times in the Phone condition compared to controls. We conclude that poor mobility judgments during a dual-task leads to unsafe mobility for those at-risk for falls. PMID:21463063

Increased cognitive load leads to impaired mobility decisions in seniors at risk for falls.

PubMed

Nagamatsu, Lindsay S; Voss, Michelle; Neider, Mark B; Gaspar, John G; Handy, Todd C; Kramer, Arthur F; Liu-Ambrose, Teresa Y L

2011-06-01

Successful mobility requires appropriate decision-making. Seniors with reduced executive functioning-such as senior fallers-may be prone to poor mobility judgments, especially under dual-task conditions. We classified participants as "At-Risk" and "Not-At-Risk" for falls using a validated physiological falls-risk assessment. Dual-task performance was assessed in a virtual reality environment where participants crossed a simulated street by walking on a manual treadmill while listening to music or conversing on a phone. Those "At-Risk" experienced more collisions with oncoming cars and had longer crossing times in the Phone condition compared to controls. We conclude that poor mobility judgments during a dual-task leads to unsafe mobility for those at-risk for falls. (c) 2011 APA, all rights reserved.

Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking.

PubMed

Gonzales, Joaquin U; James, C Roger; Yang, Hyung Suk; Jensen, Daniel; Atkins, Lee; Al-Khalil, Kareem; O'Boyle, Michael

2017-05-01

Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT. Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery. The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p <0.01). Tertiles were formed based on the percent change in gait speed for each condition. No vascular parameters differed across tertiles for DT. In contrast, carotid flow pulsatility (1.85±0.43 vs. 1.47±0.42, p=0.02) and resistance (0.75±0.07 vs. 0.68±0.07, p=0.01) indices were higher in women with more decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences. Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks. Copyright © 2017 Elsevier B.V. All rights reserved.

Gait, dual task and history of falls in elderly with preserved cognition, mild cognitive impairment, and mild Alzheimer's disease.

PubMed

Ansai, Juliana H; Andrade, Larissa P; Rossi, Paulo G; Takahashi, Anielle C M; Vale, Francisco A C; Rebelatto, José R

Studies with functional and applicable methods and new cognitive demands involving executive function are needed to improve screening, prevention and rehabilitation of cognitive impairment and falls. to identify differences in gait, dual task performances, and history of falls between elderly people with preserved cognition, mild cognitive impairment and mild Alzheimer's disease. A cross-sectional study was conducted. The sample consisted of 40 community-dwelling older adults with preserved cognition, 40 older adults with mild cognitive impairment, and 38 older adults with mild Alzheimer's disease. The assessment consisted of anamneses, gait (measured by the 10-meter walk test), dual task (measured by the Timed Up and Go Test associated with the motor-cognitive task of calling a phone number), and history of falls in the past year. There were no differences among all groups for all variables. However, the Alzheimer's disease Group performed significantly worse in the dual task than the other groups. No item of dual task could distinguish people with preserved cognition from those with mild cognitive impairment. The groups with cognitive impairment included more fallers, and specific characteristics in history of falls between groups were identified. Dual task could distinguish Alzheimer's disease patients specifically from other cognitive profiles. Copyright © 2017 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Effects of Gait Self-Efficacy and Lower-Extremity Physical Function on Dual-Task Performance in Older Adults

PubMed Central

Banducci, Sarah E.; Daugherty, Ana M.; Fanning, Jason; Awick, Elizabeth A.; Porter, Gwenndolyn C.; Burzynska, Agnieszka; Shen, Sa; Kramer, Arthur F.; McAuley, Edward

2017-01-01

Objectives. Despite evidence of self-efficacy and physical function's influences on functional limitations in older adults, few studies have examined relationships in the context of complex, real-world tasks. The present study tested the roles of self-efficacy and physical function in predicting older adults' street-crossing performance in single- and dual-task simulations. Methods. Lower-extremity physical function, gait self-efficacy, and street-crossing success ratio were assessed in 195 older adults (60–79 years old) at baseline of a randomized exercise trial. During the street-crossing task, participants walked on a self-propelled treadmill in a virtual reality environment. Participants crossed the street without distraction (single-task trials) and conversed on a cell phone (dual-task trials). Structural equation modeling was used to test hypothesized associations independent of demographic and clinical covariates. Results. Street-crossing performance was better on single-task trials when compared with dual-task trials. Direct effects of self-efficacy and physical function on success ratio were observed in dual-task trials only. The total effect of self-efficacy was significant in both conditions. The indirect path through physical function was evident in the dual-task condition only. Conclusion. Physical function can predict older adults' performance on high fidelity simulations of complex, real-world tasks. Perceptions of function (i.e., self-efficacy) may play an even greater role. The trial is registered with United States National Institutes of Health ClinicalTrials.gov (ID: NCT01472744; Fit & Active Seniors Trial). PMID:28255557

The Role of the Frontal Lobe in Complex Walking Among Patients With Parkinson's Disease and Healthy Older Adults: An fNIRS Study.

PubMed

Maidan, Inbal; Nieuwhof, Freek; Bernad-Elazari, Hagar; Reelick, Miriam F; Bloem, Bas R; Giladi, Nir; Deutsch, Judith E; Hausdorff, Jeffery M; Claassen, Jurgen A H; Mirelman, Anat

2016-11-01

Gait is influenced by higher order cognitive and cortical control mechanisms. Functional near infrared spectroscopy (fNIRS) has been used to examine frontal activation during walking in healthy older adults, reporting increased oxygenated hemoglobin (HbO2) levels during dual task walking (DT), compared with usual walking. To investigate the role of the frontal lobe during DT and obstacle negotiation, in healthy older adults and patients with Parkinson's disease (PD). Thirty-eight healthy older adults (mean age 70.4 ± 0.9 years) and 68 patients with PD (mean age 71.7 ± 1.1 years,) performed 3 walking tasks: (a) usual walking, (b) DT walking, and (c) obstacles negotiation, with fNIRS and accelerometers. Linear-mix models were used to detect changes between groups and within tasks. Patients with PD had higher activation during usual walking (P < .030). During DT, HbO2 increased only in healthy older adults (P < .001). During obstacle negotiation, HbO2 increased in patients with PD (P = .001) and tended to increase in healthy older adults (P = .053). Higher DT and obstacle cost (P < .003) and worse cognitive performance were observed in patients with PD (P = .001). A different pattern of frontal activation during walking was observed between groups. The higher activation during usual walking in patients with PD suggests that the prefrontal cortex plays an important role already during simple walking. However, higher activation relative to baseline during obstacle negotiation and not during DT in the patients with PD demonstrates that prefrontal activation depends on the nature of the task. These findings may have important implications for rehabilitation of gait in patients with PD. © The Author(s) 2016.

Gazing into Thin Air: The Dual-Task Costs of Movement Planning and Execution during Adaptive Gait

PubMed Central

Ellmers, Toby J.; Cocks, Adam J.; Doumas, Michail; Williams, A. Mark; Young, William R.

2016-01-01

We examined the effect of increased cognitive load on visual search behavior and measures of gait performance during locomotion. Also, we investigated how personality traits, specifically the propensity to consciously control or monitor movements (trait movement ‘reinvestment’), impacted the ability to maintain effective gaze under conditions of cognitive load. Healthy young adults traversed a novel adaptive walking path while performing a secondary serial subtraction task. Performance was assessed using correct responses to the cognitive task, gaze behavior, stepping accuracy, and time to complete the walking task. When walking while simultaneously carrying out the secondary serial subtraction task, participants visually fixated on task-irrelevant areas ‘outside’ the walking path more often and for longer durations of time, and fixated on task-relevant areas ‘inside’ the walkway for shorter durations. These changes were most pronounced in high-trait-reinvesters. We speculate that reinvestment-related processes placed an additional cognitive demand upon working memory. These increased task-irrelevant ‘outside’ fixations were accompanied by slower completion rates on the walking task and greater gross stepping errors. Findings suggest that attention is important for the maintenance of effective gaze behaviors, supporting previous claims that the maladaptive changes in visual search observed in high-risk older adults may be a consequence of inefficiencies in attentional processing. Identifying the underlying attentional processes that disrupt effective gaze behaviour during locomotion is an essential step in the development of rehabilitation, with this information allowing for the emergence of interventions that reduce the risk of falling. PMID:27824937

The effect of cognitive-motor dual task training with the biorescue force platform on cognition, balance and dual task performance in institutionalized older adults: a randomized controlled trial

PubMed Central

Delbroek, Tom; Vermeylen, Wietse; Spildooren, Joke

2017-01-01

[Purpose] This study investigates whether cognition, balance and dual task performance in institutionalized older adults improves by a virtual reality dual task training. [Subjects and Methods] Randomized controlled trial; Twenty institutionalized older adults with mild cognitive impairment (13 female, 7 male; average age, 87.2 ± 5.96 years) were randomized to the intervention (i.e. Virtual reality dual-task training using the BioRescue) or control group (no additional training). The intervention group took part in a 6-week training program while the elderly in the control group maintained their daily activities. Balance was measured with the Instrumented Timed Up-and-Go Test with and without a cognitive task. The Observed Emotion Rating Scale and Intrinsic Motivation Inventory were administered to evaluate the emotions and motivation regarding the exergaming program. [Results] The intervention group improved significantly on the total Timed Up-and-Go duration and the turn-to-sit duration during single-task walking in comparison to the control group who received no additional training. Participants found the virtual reality dual task training pleasant and useful for their concentration, memory and balance. Pleasure and alertness were the two emotions which were mostly seen during the intervention. [Conclusion] The BioRescue is a pleasant and interesting treatment method, well suited for institutionalized older adults in need of lifelong physical therapy. PMID:28744033

Improving balance, mobility, and dual-task performance in an adolescent with cerebral palsy: A case report.

PubMed

Fisher-Pipher, Sarah; Kenyon, Lisa K; Westman, Marci

2017-07-01

Improving functional mobility is often a desired outcome for adolescents with cerebral palsy (CP). Traditional neurorehabilitation approaches are frequently directed at impairments; however, improvements may not be carried over into functional mobility. The purpose of this case report was to describe the examination, intervention, and outcomes of a task-oriented physical therapy intervention program to improve dynamic balance, functional mobility, and dual-task performance in an adolescent with CP. The participant was a 15-year-old girl with spastic triplegic CP (Gross Motor Classification System Level II). Examination procedures included the Canadian Occupational Performance Measure, 6-minute walk test, Muscle Power Sprint Test, 10 x 5-meter sprint test, Timed Up and Down Stairs Test, Gross Motor Function Measure, Gillette Functional Assessment Questionnaire, and functional lower extremity strength tests. Intervention focused on task-oriented dynamic balance and mobility tasks that incorporated coordination and speed demands as well as task-specific lower extremity and trunk strengthening activities. Dual task demands were integrated into all intervention activities. Post-intervention testing revealed improvements in cardiovascular endurance, anaerobic power, agility, stair climbing, gross motor skills, and mobility. The participant appeared to benefit from a task-oriented program to improve dynamic balance, functional mobility, and dual-task performance.

The Effect of Prior Concussion History on Dual-Task Gait following a Concussion.

PubMed

Howell, David R; Beasley, Michael; Vopat, Lisa; Meehan, William P

2017-02-15

Sustaining repeated concussions has been associated with worse outcomes after additional injuries. This effect has been identified using symptom inventories and neurocognitive tests; however, few investigations have examined how a prior concussion history affects gait soon after a subsequent concussion. We examined the gait characteristics of athletes with no documented concussion history (n = 31), athletes recovering from their first lifetime concussion (n = 15), and athletes recovering from their second or greater lifetime concussion (n = 22). All participants completed a single-task and dual-task gait examination, a medical history questionnaire, and a postconcussion symptom scale. Multivariate analyses of covariance (MANCOVA) models were used to evaluate mean gait differences among groups, and Spearman's ρ analyses were used to assess correlations between the number of lifetime concussions and gait characteristics. Patients reporting to the clinic with their second or greater lifetime concussion demonstrated smaller stride lengths than healthy control participants during dual-task walking (p = 0.01; d = 0.70). A moderate but insignificant correlation was detected between dual-task gait speed and the number of prior concussions (ρ = 0.41, p = 0.07). These results indicate that a cumulative effect of concussions across the lifetime may contribute to worsening dual-task dynamic motor function after concussion.

Does It Really Matter Where You Look When Walking on Stairs? Insights from a Dual-Task Study

PubMed Central

Miyasike-daSilva, Veronica; McIlroy, William E.

2012-01-01

Although the visual system is known to provide relevant information to guide stair locomotion, there is less understanding of the specific contributions of foveal and peripheral visual field information. The present study investigated the specific role of foveal vision during stair locomotion and ground-stairs transitions by using a dual-task paradigm to influence the ability to rely on foveal vision. Fifteen healthy adults (26.9±3.3 years; 8 females) ascended a 7-step staircase under four conditions: no secondary tasks (CONTROL); gaze fixation on a fixed target located at the end of the pathway (TARGET); visual reaction time task (VRT); and auditory reaction time task (ART). Gaze fixations towards stair features were significantly reduced in TARGET and VRT compared to CONTROL and ART. Despite the reduced fixations, participants were able to successfully ascend stairs and rarely used the handrail. Step time was increased during VRT compared to CONTROL in most stair steps. Navigating on the transition steps did not require more gaze fixations than the middle steps. However, reaction time tended to increase during locomotion on transitions suggesting additional executive demands during this phase. These findings suggest that foveal vision may not be an essential source of visual information regarding stair features to guide stair walking, despite the unique control challenges at transition phases as highlighted by phase-specific challenges in dual-tasking. Instead, the tendency to look at the steps in usual conditions likely provides a stable reference frame for extraction of visual information regarding step features from the entire visual field. PMID:22970297

Multicomponent physical exercise with simultaneous cognitive training to enhance dual-task walking of older adults: a secondary analysis of a 6-month randomized controlled trial with 1-year follow-up.

PubMed

Eggenberger, Patrick; Theill, Nathan; Holenstein, Stefan; Schumacher, Vera; de Bruin, Eling D

2015-01-01

About one-third of people older than 65 years fall at least once a year. Physical exercise has been previously demonstrated to improve gait, enhance physical fitness, and prevent falls. Nonetheless, the addition of cognitive training components may potentially increase these effects, since cognitive impairment is related to gait irregularities and fall risk. We hypothesized that simultaneous cognitive-physical training would lead to greater improvements in dual-task (DT) gait compared to exclusive physical training. Elderly persons older than 70 years and without cognitive impairment were randomly assigned to the following groups: 1) virtual reality video game dancing (DANCE), 2) treadmill walking with simultaneous verbal memory training (MEMORY), or 3) treadmill walking (PHYS). Each program was complemented with strength and balance exercises. Two 1-hour training sessions per week over 6 months were applied. Gait variables, functional fitness (Short Physical Performance Battery, 6-minute walk), and fall frequencies were assessed at baseline, after 3 months and 6 months, and at 1-year follow-up. Multiple regression analyses with planned comparisons were carried out. Eighty-nine participants were randomized to three groups initially; 71 completed the training and 47 were available at 1-year follow-up. DANCE/MEMORY showed a significant advantage compared to PHYS in DT costs of step time variability at fast walking (P=0.044). Training-specific gait adaptations were found on comparing DANCE and MEMORY: DANCE reduced step time at fast walking (P=0.007) and MEMORY reduced gait variability in DT and DT costs at preferred walking speed (both trend P=0.062). Global linear time effects showed improved gait (P<0.05), functional fitness (P<0.05), and reduced fall frequency (-77%, P<0.001). Only single-task fast walking, gait variability at preferred walking speed, and Short Physical Performance Battery were reduced at follow-up (all P<0.05 or trend). Long-term multicomponent cognitive-physical and exclusive physical training programs demonstrated similar potential to counteract age-related decline in physical functioning.

Multicomponent physical exercise with simultaneous cognitive training to enhance dual-task walking of older adults: a secondary analysis of a 6-month randomized controlled trial with 1-year follow-up

PubMed Central

Eggenberger, Patrick; Theill, Nathan; Holenstein, Stefan; Schumacher, Vera; de Bruin, Eling D

2015-01-01

Background About one-third of people older than 65 years fall at least once a year. Physical exercise has been previously demonstrated to improve gait, enhance physical fitness, and prevent falls. Nonetheless, the addition of cognitive training components may potentially increase these effects, since cognitive impairment is related to gait irregularities and fall risk. We hypothesized that simultaneous cognitive–physical training would lead to greater improvements in dual-task (DT) gait compared to exclusive physical training. Methods Elderly persons older than 70 years and without cognitive impairment were randomly assigned to the following groups: 1) virtual reality video game dancing (DANCE), 2) treadmill walking with simultaneous verbal memory training (MEMORY), or 3) treadmill walking (PHYS). Each program was complemented with strength and balance exercises. Two 1-hour training sessions per week over 6 months were applied. Gait variables, functional fitness (Short Physical Performance Battery, 6-minute walk), and fall frequencies were assessed at baseline, after 3 months and 6 months, and at 1-year follow-up. Multiple regression analyses with planned comparisons were carried out. Results Eighty-nine participants were randomized to three groups initially; 71 completed the training and 47 were available at 1-year follow-up. DANCE/MEMORY showed a significant advantage compared to PHYS in DT costs of step time variability at fast walking (P=0.044). Training-specific gait adaptations were found on comparing DANCE and MEMORY: DANCE reduced step time at fast walking (P=0.007) and MEMORY reduced gait variability in DT and DT costs at preferred walking speed (both trend P=0.062). Global linear time effects showed improved gait (P<0.05), functional fitness (P<0.05), and reduced fall frequency (−77%, P<0.001). Only single-task fast walking, gait variability at preferred walking speed, and Short Physical Performance Battery were reduced at follow-up (all P<0.05 or trend). Conclusion Long-term multicomponent cognitive–physical and exclusive physical training programs demonstrated similar potential to counteract age-related decline in physical functioning. PMID:26604719

A cognitive-motor intervention using a dance video game to enhance foot placement accuracy and gait under dual task conditions in older adults: a randomized controlled trial.

PubMed

Pichierri, Giuseppe; Murer, Kurt; de Bruin, Eling D

2012-12-14

Computer-based interventions have demonstrated consistent positive effects on various physical abilities in older adults. This study aims to compare two training groups that achieve similar amounts of strength and balance exercise where one group receives an intervention that includes additional dance video gaming. The aim is to investigate the different effects of the training programs on physical and psychological parameters in older adults. Thirty-one participants (mean age ± SD: 86.2 ± 4.6 years), residents of two Swiss hostels for the aged, were randomly assigned to either the dance group (n = 15) or the control group (n = 16). The dance group absolved a twelve-week cognitive-motor exercise program twice weekly that comprised progressive strength and balance training supplemented with additional dance video gaming. The control group performed only the strength and balance exercises during this period. Outcome measures were foot placement accuracy, gait performance under single and dual task conditions, and falls efficacy. After the intervention between-group comparison revealed significant differences for gait velocity (U = 26, P = .041, r = .45) and for single support time (U = 24, P = .029, r = .48) during the fast walking dual task condition in favor of the dance group. No significant between-group differences were observed either in the foot placement accuracy test or in falls efficacy. There was a significant interaction in favor of the dance video game group for improvements in step time. Significant improved fast walking performance under dual task conditions (velocity, double support time, step length) was observed for the dance video game group only. These findings suggest that in older adults a cognitive-motor intervention may result in more improved gait under dual task conditions in comparison to a traditional strength and balance exercise program. This trial has been registered under ISRCTN05350123 (www.controlled-trials.com)

Non-MTC gait cycles: An adaptive toe trajectory control strategy in older adults.

PubMed

Santhiranayagam, Braveena K; Sparrow, W A; Lai, Daniel T H; Begg, Rezaul K

2017-03-01

Minimum-toe-clearance (MTC) above the walking surface is a critical representation of toe-trajectory control due to its association with tripping risk. Not all gait cycles exhibit a clearly defined MTC within the swing phase but there have been few previous accounts of the biomechanical characteristics of non-MTC gait cycles. The present report investigated the within-subject non-MTC gait cycle characteristics of 15 older adults (mean 73.1 years) and 15 young controls (mean 26.1 years). Participants performed the following tasks on a motorized treadmill: preferred speed walking, dual task walking (carrying a glass of water) and a dual-task speed-matched control. Toe position-time coordinates were acquired using a 3 dimensional motion capture system. When MTC was present, toe height at MTC (MTC height ) was extracted. The proportion of non-MTC gait cycles was computed for the age groups and individuals. For non-MTC gait cycles an 'indicative' toe height at the individual's average swing phase time (MTC time ) for observed MTC cycles was averaged across multiple non-MTC gait cycles. In preferred-speed walking Young demonstrated 2.9% non-MTC gait cycles and Older 18.7%. In constrained walking conditions both groups increased non-MTC gait cycles and some older adults revealed over 90%, confirming non-MTC gait cycles as an ageing-related phenomenon in lower limb trajectory control. For all participants median indicative toe-height on non-MTC gait cycles was greater than median MTC height . This result suggests that eliminating the biomechanically hazardous MTC event by adopting more of the higher-clearance non-MTC gait cycles, is adaptive in reducing the likelihood of toe-ground contact. Copyright © 2017 Elsevier B.V. All rights reserved.

Everyday multitasking habits: University students seamlessly text and walk on a split-belt treadmill.

PubMed

Hinton, Dorelle Clare; Cheng, Yeu-Yao; Paquette, Caroline

2018-01-01

With increasing numbers of adults owning a cell phone, walking while texting has become common in daily life. Previous research has shown that walking is not entirely automated and when challenged with a secondary task, normal walking patterns are disrupted. This study investigated the effects of texting on the walking patterns of healthy young adults while walking on a split-belt treadmill. Following full adaptation to the split-belt treadmill, thirteen healthy adults (23±3years) walked on a tied-belt and split-belt treadmill, both with and without a simultaneous texting task. Inertial-based movement monitors recorded spatiotemporal components of gait and stability. Measures of spatial and temporal gait symmetry were calculated to compare gait patterns between treadmill (tied-belt and split-belt) and between texting (absent or present) conditions. Typing speed and accuracy were recorded to monitor texting performance. Similar to previous research, the split-belt treadmill caused an alteration to both spatial and temporal aspects of gait, but not to time spent in dual support or stability. However, all participants successfully maintained balance while walking and were able to perform the texting task with no significant change to accuracy or speed on either treadmill. From this paradigm it is evident that when university students are challenged to text while walking on either a tied-belt or split-belt treadmill, without any other distraction, their gait is minimally affected and they are able to maintain texting performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Working memory in wayfinding-a dual task experiment in a virtual city.

PubMed

Meilinger, Tobias; Knauff, Markus; Bülthoff, Heinrich H

2008-06-01

This study examines the working memory systems involved in human wayfinding. In the learning phase, 24 participants learned two routes in a novel photorealistic virtual environment displayed on a 220° screen while they were disrupted by a visual, a spatial, a verbal, or-in a control group-no secondary task. In the following wayfinding phase, the participants had to find and to "virtually walk" the two routes again. During this wayfinding phase, a number of dependent measures were recorded. This research shows that encoding wayfinding knowledge interfered with the verbal and with the spatial secondary task. These interferences were even stronger than the interference of wayfinding knowledge with the visual secondary task. These findings are consistent with a dual-coding approach of wayfinding knowledge. 2008 Cognitive Science Society, Inc.

Residual standard deviation: Validation of a new measure of dual-task cost in below-knee prosthesis users.

PubMed

Howard, Charla L; Wallace, Chris; Abbas, James; Stokic, Dobrivoje S

2017-01-01

We developed and evaluated properties of a new measure of variability in stride length and cadence, termed residual standard deviation (RSD). To calculate RSD, stride length and cadence are regressed against velocity to derive the best fit line from which the variability (SD) of the distance between the actual and predicted data points is calculated. We examined construct, concurrent, and discriminative validity of RSD using dual-task paradigm in 14 below-knee prosthesis users and 13 age- and education-matched controls. Subjects walked first over an electronic walkway while performing separately a serial subtraction and backwards spelling task, and then at self-selected slow, normal, and fast speeds used to derive the best fit line for stride length and cadence against velocity. Construct validity was demonstrated by significantly greater increase in RSD during dual-task gait in prosthesis users than controls (group-by-condition interaction, stride length p=0.0006, cadence p=0.009). Concurrent validity was established against coefficient of variation (CV) by moderate-to-high correlations (r=0.50-0.87) between dual-task cost RSD and dual-task cost CV for both stride length and cadence in prosthesis users and controls. Discriminative validity was documented by the ability of dual-task cost calculated from RSD to effectively differentiate prosthesis users from controls (area under the receiver operating characteristic curve, stride length 0.863, p=0.001, cadence 0.808, p=0.007), which was better than the ability of dual-task cost CV (0.692, 0.648, respectively, not significant). These results validate RSD as a new measure of variability in below-knee prosthesis users. Future studies should include larger cohorts and other populations to ascertain its generalizability. Copyright © 2016 Elsevier B.V. All rights reserved.

The relationship between physical activity, and physical performance and psycho-cognitive functioning in older adults living in residential aged care facilities.

PubMed

Bootsman, Natalia J M; Skinner, Tina L; Lal, Ravin; Glindemann, Delma; Lagasca, Carmela; Peeters, G M E E Geeske

2018-02-01

Insight into modifiable factors related to falls risk in older adults living in residential aged care facilities (RACFs) is necessary to tailor preventive strategies for this high-risk population. Associations between physical activity (PA), physical performance and psycho-cognitive functioning have been understudied in aged care residents. This study investigated associations between PA, and both physical performance and psycho-cognitive functioning in older adults living in RACFs. Cross-sectional study. Forty-four residents aged 85±8years were recruited from four RACFs located in Southeast Queensland. PA was assessed as the average time spent walking in hours/day using activPAL3™. Physical performance tests included balance, gait speed, dual-task ability, reaction time, coordination, grip strength, and leg strength and power. Psycho-cognitive questionnaires included quality of life, balance confidence, fear of falling and cognitive functioning. Associations between PA and each outcome measure were analysed using linear or ordinal regression models. The average time spent walking was 0.5±0.4h/day. Higher levels of PA were significantly associated with better balance (compared with low PA, medium: B=1.6; high: B=1.3) and dual-task ability (OR=7.9 per 0.5h/day increase). No statistically significant associations were found between PA and the other physical and psycho-cognitive measures. More physically active residents scored higher on balance and dual-task ability, which are key predictors of falls risk. This suggests that physical activity programs targeting balance and dual-task ability could help prevent falls in aged care residents. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

A dedicated system for topographical working memory: evidence from domain-specific interference tests.

PubMed

Piccardi, L; Nori, R; Boccia, M; Barbetti, S; Verde, P; Guariglia, C; Ferlazzo, F

2015-08-01

In the present study, we used single- and dual-task conditions to investigate the nature of topographical working memory to better understand what type of task can hamper performance during navigation. During dual-task conditions, we considered four different sources of interference: motor (M), spatial motor (SM), verbal (i.e. articulatory suppression AS) and spatial environmental (SE). In order to assess the nature of topographical working memory, we used the Walking Corsi Test, asking the participants to perform two tasks simultaneously (M, SM, AS and SE). Our results showed that only spatial-environmental interference hampers the execution of a topographical working memory task, suggesting a task-domain-specific effect. We also found general gender differences in the topographical working memory capabilities: men were more proficient than women, regardless of the type of interferences. However, like men, women performed worse when a spatial-environmental interference was present.

The Effect of Chinese Yuanji-Dance on Dynamic Balance and the Associated Attentional Demands in Elderly Adults

PubMed Central

Wu, Wen-Lan; Wei, Ta-Sen; Chen, Shen-Kai; Chang, Jyh-Jong; Guo, Lan-Yuen; Lin, Hwai-Ting

2010-01-01

Walking performance changes with age. This has implications for the problem of falls in older adults. The aim of this study was to investigate the effects of Yuanji-Dance practice on walking balance and the associated attention demand in healthy elderly. Fifteen community-dwelling elderly (comparison group, no regular exercise habit) and fifteen Yuanji- Dance elderly (exercise group, dancing experience: 5.40 ± 1.95 years), aged 60-70 years, were included in this study. The subjects in exercise group participated in a 90-minute Yuanji-Dance practice at least three times per week and the comparison group continued their normal daily physical activity. Walking balance measures (including walking velocity, step length, step width, and percentage of time spent in double limb support, COM velocity and COM-COP inclination angles) and attentional demand tests (button reaction time and accuracy) were conducted under different conditions. Our results showed that stride lengths, walking velocities, peak A/P velocities (AP V) of the COM, medial COM-COP inclination (M angle) angles, reaction time, and accuracy decrease significantly as the dual-task (walking plus hand button pressing tasks) applied for either the comparison or exercise groups. These results demonstrated that walking performance is attenuated in our elderly participants as the cognitive tasks applied. Analysis also identified a significantly faster RT for our exercise group both in standing and walking conditions. This may indicate that physical exercise (Yuanji-Dance) may have facilitating effects on general cognitive and perceptual- motor functions. This implies that Chinese Yuanji-Dance practice for elderly adults may improve their personal safety when walking especially under the condition of multiple task demand. Key points The purpose of this study was to investigate the training effects of a Chinese traditional exercise, Yuanji-Dance, on walking balance and the associated attention demand in the healthy elderly. Walking performance is attenuated in elderly participants as the cognitive tasks applied. A significantly faster reaction time for our exercise group both in standing and walking conditions. Yuanji-Dance exercise training can improve the information processing speed of elderly people and has no influence of the dynamic walking balance. PMID:24149395

Improving Motor Control in Walking: A Randomized Clinical Trial in Older Adults with Subclinical Walking Difficulty

PubMed Central

Brach, Jennifer S.; Lowry, Kristin; Perera, Subashan; Hornyak, Victoria; Wert, David; Studenski, Stephanie A.; VanSwearingen, Jessie M.

2016-01-01

Objective The objective was to test the proposed mechanism of action of a task-specific motor learning intervention by examining its effect on measures of the motor control of gait. Design Single blinded randomized clinical trial. Setting University research laboratory. Participants Forty older adults 65 years of age and older, with gait speed >1.0 m/s and impaired motor skill (Figure of 8 walk time > 8 secs). Interventions The two interventions included a task-oriented motor learning and a standard exercise program. Both interventions lasted 12 weeks, with twice weekly one hour physical therapist supervised sessions. Main Outcome Measures Two measure of the motor control of gait, gait variability and smoothness of walking, were assessed pre and post intervention by assessors masked to treatment arm. Results Of 40 randomized subjects; 38 completed the trial (mean age 77.1±6.0 years). Motor control group improved more than standard group in double support time variability (0.13 vs. 0.05 m/s; adjusted difference, AD=0.006, p=0.03). Smoothness of walking in the anterior/posterior direction improved more in motor control than standard for all conditions (usual: AD=0.53, p=0.05; narrow: AD=0.56, p=0.01; dual task: AD=0.57, p=0.04). Conclusions Among older adults with subclinical walking difficulty, there is initial evidence that task-oriented motor learning exercise results in gains in the motor control of walking, while standard exercise does not. Task-oriented motor learning exercise is a promising intervention for improving timing and coordination deficits related to mobility difficulties in older adults, and needs to be evaluated in a definitive larger trial. PMID:25448244

Texting during stair negotiation and implications for fall risk.

PubMed

Hashish, Rami; Toney-Bolger, Megan E; Sharpe, Sarah S; Lester, Benjamin D; Mulliken, Adam

2017-10-01

Walking requires the integration of the sensory and motor systems. Cognitive distractions have been shown to interfere with negotiation of complex walking environments, especially in populations at greater risk for falls (e.g. the elderly). With the pervasiveness of mobile messaging and the recent introduction of augmented reality mobile gaming, it is increasingly important to understand how distraction associated with the simultaneous use of a mobile device impacts navigation of the complex walking environments experienced in daily life. In this study, we investigated how gait kinematics were altered when participants performed a texting task during step negotiation. Twenty participants (13 female, 7 males) performed a series of walking trials involving a step-deck obstacle, consisting of at least 3 texting trials and 3 non-texting trials. When texting, participants ascended more slowly and demonstrated reduced dual-step foot toe clearance. Participants similarly descended more slowly when texting and demonstrated reduced single-step foot heel clearance as well as reduced dual-step foot fore-aft heel clearance. These data support the conclusion that texting during stair negotiation results in changes to gait kinematics that may increase the potential for gait disruptions, falls, and injury. Further research should examine the effect texting has on performing other common complex locomotor tasks, actual fall risk, and the patterns of resulting injury rate and severity when negotiating complex environments. Copyright © 2017 Elsevier B.V. All rights reserved.

A 9-Week Jaques-Dalcroze Eurhythmics Intervention Improves Single and Dual-Task Gait Speed in Community-Dwelling Older People.

PubMed

Ferguson-Stegall, Lisa; Vang, Mandy; Wolfe, Anthony S; Thomsen, Kathy M

2017-09-01

Falls are a major public health concern among older adults, and most occur while walking, especially under dualtask conditions. Jaques-Dalcroze eurhythmics (JDE) is a music-based movement training program that emphasizes multitask coordinated movement. A previous 6-mo JDE study in older people demonstrated improved gait and balance; however, the effects of short-term JDE interventions on fall risk-related outcomes are largely unknown. We conducted a preliminary investigation on whether a 9-week JDE intervention improved gait and stability in a community-dwelling older cohort, hypothesizing that improvements would occur in all outcome measures. Nine participants (78.9 ± 12.3 y) completed the supervised JDE intervention (once/week for 60 min). Gait speed was determined by the 6-m timed walk test (6MTW); dual-task gait speed was determined by another 6MTW while counting backward from 50 aloud; and coordinated stability was assessed using a Swaymeter-like device. Gait speed (0.92 ± 0.11 vs 1.04 ± 0.12 m/sec, P = .04) and dual-task gait speed (0.77 ± 0.09 vs 0.92 ± 0.11 m/sec, P = .0005) significantly improved. This novel intervention is an effective short-term physical activity option for those that plan physical activity or fall-risk reduction programs for the older people.

Cognitive Resources Necessary for Motor Control in Older Adults Are Reduced by Walking and Coordination Training

PubMed Central

Godde, Ben; Voelcker-Rehage, Claudia

2017-01-01

We examined if physical exercise interventions were effective to reduce cognitive brain resources recruited while performing motor control tasks in older adults. Forty-three older adults (63–79 years of age) participated in either a walking (n = 17) or a motor coordination (n = 15) intervention (1 year, 3 times per week) or were assigned to a control group (n = 11) doing relaxation and stretching exercises. Pre and post the intervention period, we applied functional MRI to assess brain activation during imagery of forward and backward walking and during counting backwards from 100 as control task. In both experimental groups, activation in the right dorsolateral prefrontal cortex (DLPFC) during imagery of forward walking decreased from pre- to post-test (Effect size: −1.55 and −1.16 for coordination and walking training, respectively; Cohen’s d). Regression analysis revealed a significant positive association between initial motor status and activation change in the right DLPFC (R2 = 0.243, F(3,39) = 4.18, p = 0.012). Participants with lowest motor status at pretest profited most from the interventions. Data suggest that physical training in older adults is effective to free up cognitive resources otherwise needed for the control of locomotion. Training benefits may become particularly apparent in so-called dual-task situations where subjects must perform motor and cognitive tasks concurrently. PMID:28443006

Fear of falling is associated with prolonged anticipatory postural adjustment during gait initiation under dual-task conditions in older adults.

PubMed

Uemura, Kazuki; Yamada, Minoru; Nagai, Koutatsu; Tanaka, Buichi; Mori, Shuhei; Ichihashi, Noriaki

2012-02-01

Little is known about dynamic balance control under dual-task conditions in older adults with fear of falling (FoF). The purpose of this study was to examine the effect of FoF on anticipatory postural adjustment (APA) during gait initiation under dual-task conditions in older adults. Fifty-seven elderly volunteers (age, 79.2 [6.8] years) from the community participated in this study. Each participant was categorised into either the Fear (n=24) or No-fear (n=33) group on the basis of the presence or absence of FoF. Under single- and dual-task conditions, centre of pressure (COP) data were collected while the participants performed gait initiation trials from a starting position on a force platform. We also performed a 10-m walking test (WT), a timed up & go test (TUG), and a functional reach test (FR). The reaction and APA phases were measured from the COP data. The results showed that under the dual-task condition, the Fear group had significantly longer APA phases than the No-fear group, although no significant differences were observed between the 2 groups in the reaction and APA phases under the single-task condition and in any clinical measurements (WT, TUG, and FR). Our findings suggest that specific deficits in balance control occur in subjects with FoF during gait initiation while dual tasking, even if their physical functions are comparable to subjects without FoF. Copyright © 2011 Elsevier B.V. All rights reserved.

Relative and absolute reliability of the clinical version of the Narrow Path Walking Test (NPWT) under single and dual task conditions.

PubMed

Gimmon, Yoav; Jacob, Grinshpon; Lenoble-Hoskovec, Constanze; Büla, Christophe; Melzer, Itshak

2013-01-01

Decline in gait stability has been associated with increased fall risk in older adults. Reliable and clinically feasible methods of gait instability assessment are needed. This study evaluated the relative and absolute reliability and concurrent validity of the testing procedure of the clinical version of the Narrow Path Walking Test (NPWT) under single task (ST) and dual task (DT) conditions. Thirty independent community-dwelling older adults (65-87 years) were tested twice. Participants were instructed to walk within the 6-m narrow path without stepping out. Trial time, number of steps, trial velocity, number of step errors, and number of cognitive task errors were determined. Intraclass correlation coefficients (ICCs) were calculated as indices of agreement, and a graphic approach called "mountain plot" was applied to help interpret the direction and magnitude of disagreements between testing procedures. Smallest detectable change and smallest real difference (SRD) were computed to determine clinically relevant improvement at group and individual levels, respectively. Concurrent validity was assessed using Performance Oriented Mobility Assessment Tool (POMA) and the Short Physical Performance Battery (SPPB). Test-retest agreement (ICC1,2) varied from 0.77 to 0.92 in ST and from 0.78 to 0.92 in DT conditions, with no apparent systematic differences between testing procedures demonstrated by the mountain plot graphs. Smallest detectable change and smallest real change were small for motor task performance and larger for cognitive errors. Significant correlations were observed for trial velocity and trial time with POMA and SPPB. The present results indicate that the NPWT testing procedure is highly reliable and reproducible. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Obesity-specific neural cost of maintaining gait performance under complex conditions in community-dwelling older adults.

PubMed

Osofundiya, Olufunmilola; Benden, Mark E; Dowdy, Diane; Mehta, Ranjana K

2016-06-01

Recent evidence of obesity-related changes in the prefrontal cortex during cognitive and seated motor activities has surfaced; however, the impact of obesity on neural activity during ambulation remains unclear. The purpose of this study was to determine obesity-specific neural cost of simple and complex ambulation in older adults. Twenty non-obese and obese individuals, 65years and older, performed three tasks varying in the types of complexity of ambulation (simple walking, walking+cognitive dual-task, and precision walking). Maximum oxygenated hemoglobin, a measure of neural activity, was measured bilaterally using a portable functional near infrared spectroscopy system, and gait speed and performance on the complex tasks were also obtained. Complex ambulatory tasks were associated with ~2-3.5 times greater cerebral oxygenation levels and ~30-40% slower gait speeds when compared to the simple walking task. Additionally, obesity was associated with three times greater oxygenation levels, particularly during the precision gait task, despite obese adults demonstrating similar gait speeds and performances on the complex gait tasks as non-obese adults. Compared to existing studies that focus solely on biomechanical outcomes, the present study is one of the first to examine obesity-related differences in neural activity during ambulation in older adults. In order to maintain gait performance, obesity was associated with higher neural costs, and this was augmented during ambulatory tasks requiring greater precision control. These preliminary findings have clinical implications in identifying individuals who are at greater risk of mobility limitations, particularly when performing complex ambulatory tasks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Gait characteristics under different walking conditions: Association with the presence of cognitive impairment in community-dwelling older people

PubMed Central

Fransen, Erik; Perkisas, Stany; Verhoeven, Veronique; Beauchet, Olivier; Remmen, Roy

2017-01-01

Background Gait characteristics measured at usual pace may allow profiling in patients with cognitive problems. The influence of age, gender, leg length, modified speed or dual tasking is unclear. Methods Cross-sectional analysis was performed on a data registry containing demographic, physical and spatial-temporal gait parameters recorded in five walking conditions with a GAITRite® electronic carpet in community-dwelling older persons with memory complaints. Four cognitive stages were studied: cognitively healthy individuals, mild cognitive impaired patients, mild dementia patients and advanced dementia patients. Results The association between spatial-temporal gait characteristics and cognitive stages was the most prominent: in the entire study population using gait speed, steps per meter (translation for mean step length), swing time variability, normalised gait speed (corrected for leg length) and normalised steps per meter at all five walking conditions; in the 50-to-70 years old participants applying step width at fast pace and steps per meter at usual pace; in the 70-to-80 years old persons using gait speed and normalised gait speed at usual pace, fast pace, animal walk and counting walk or steps per meter and normalised steps per meter at all five walking conditions; in over-80 years old participants using gait speed, normalised gait speed, steps per meter and normalised steps per meter at fast pace and animal dual-task walking. Multivariable logistic regression analysis adjusted for gender predicted in two compiled models the presence of dementia or cognitive impairment with acceptable accuracy in persons with memory complaints. Conclusion Gait parameters in multiple walking conditions adjusted for age, gender and leg length showed a significant association with cognitive impairment. This study suggested that multifactorial gait analysis could be more informative than using gait analysis with only one test or one variable. Using this type of gait analysis in clinical practice could facilitate screening for cognitive impairment. PMID:28570662

Gait and risk of falls associated with frontal cognitive functions at different stages of Alzheimer's disease.

PubMed

Coelho, Flávia Gomes de Melo; Stella, Florindo; de Andrade, Larissa Pires; Barbieri, Fabio Augusto; Santos-Galduróz, Ruth Ferreira; Gobbi, Sebastião; Costa, José Luiz Riani; Gobbi, Lilian Teresa Bucken

2012-09-01

The decline in frontal cognitive functions contributes to alterations of gait and increases the risk of falls in patients with dementia, a category which included Alzheimer's disease (AD). The objective of the present study was to compare the gait parameters and the risk of falls among patients at different stages of AD, and to relate these variables with cognitive functions. This is a cross-sectional study with 23 patients with mild and moderate AD. The Clinical Dementia Rating was used to classify the dementia severity. The kinematic parameters of gait (cadence, stride length, and stride speed) were analyzed under two conditions: (a) single task (free gait) and (b) dual task (walking and counting down). The risk of falls was evaluated using the Timed Up-and-Go test. The frontal cognitive functions were evaluated using the Frontal Assessment Battery (FAB), the Clock Drawing Test (CDT) and the Symbol Search Subtest. The patients who were at the moderate stage suffered reduced performance in their stride length and stride speed in the single task and had made more counting errors in the dual task and still had a higher fall risk. Both the mild and the moderate patients exhibited significant decreases in stride length, stride speed and cadence in the dual task. Was detected a significant correlation between CDT, FAB, and stride speed in the dual task condition. We also found a significant correlation between subtest Similarities, FAB and cadence in the dual task condition. The dual task produced changes in the kinematic parameters of gait for the mild and moderate AD patients and the gait alterations are related to frontal cognitive functions, particularly executive functions.

The Effects of Highly Challenging Balance Training in Elderly With Parkinson's Disease: A Randomized Controlled Trial.

PubMed

Conradsson, David; Löfgren, Niklas; Nero, Håkan; Hagströmer, Maria; Ståhle, Agneta; Lökk, Johan; Franzén, Erika

2015-10-01

Highly challenging exercises have been suggested to induce neuroplasticity in individuals with Parkinson's disease (PD); however, its effect on clinical outcomes remains largely unknown. To evaluate the short-term effects of the HiBalance program, a highly challenging balance-training regimen that incorporates both dual-tasking and PD-specific balance components, compared with usual care in elderly with mild to moderate PD. Participants with PD (n = 100) were randomized, either to the 10-week HiBalance program (n = 51) or to the control group (n = 49). Participants were evaluated before and after the intervention. The main outcomes were balance performance (Mini-BESTest), gait velocity (during normal and dual-task gait), and concerns about falling (Falls Efficacy Scale-International). Performance of a cognitive task while walking, physical activity level (average steps per day), and activities of daily living were secondary outcomes. A total of 91 participants completed the study. After the intervention, the between group comparison showed significantly improved balance and gait performance in the training group. Moreover, although no significant between group difference was observed regarding gait performance during dual-tasking; the participants in the training group improved their performance of the cognitive task while walking, as compared with the control group. Regarding physical activity levels and activities of daily living, in comparison to the control group, favorable results were found for the training group. No group differences were found for concerns about falling. The HiBalance program significantly benefited balance and gait abilities when compared with usual care and showed promising transfer effects to everyday living. Long-term follow-up assessments will further explore these effects. © The Author(s) 2015.

Overload From Anxiety: A Non-Motor Cause for Gait Impairments in Parkinson's Disease.

PubMed

Ehgoetz Martens, Kaylena A; Silveira, Carolina R A; Intzandt, Brittany N; Almeida, Quincy J

2018-01-01

Threatening situations lead to observable gait deficits in individuals with Parkinson's disease (PD) who suffer from high trait anxiety levels. The specific characteristics of gait that are affected appear to be similar to behaviors observed while walking during a dual-task (DT) condition. Yet, it remains unclear whether anxiety is similar to a cognitive load. If it were, then those with PD who have high trait anxiety might be expected to be more susceptible to DT interference during walking. Thus, the overall aim of this study was to evaluate whether trait anxiety influences gait during single-task (ST) and DT walking. Seventy participants (high-anxiety PD [HA-PD], N=26; low-anxiety PD [LA-PD], N=26; healthy control [HC], N=18) completed three ST and three DT walking trials on a data-collecting carpet. The secondary task consisted of digit monitoring while walking. Results showed that during both ST and DT gait, the HA-PD group demonstrated significant reductions in walking speed and step length, as well as increased step length variability and step time variability compared with healthy controls and the LA-PD group. Notably, ST walking in the HA-PD group resembled (i.e., it was not significantly different from) the gait behaviors seen during a DT in the LA-PD and HC groups. These results suggest that trait anxiety may consume processing resources and limit the ability to compensate for gait impairments in PD.

WHY DOES OLDER ADULTS' BALANCE BECOME LESS STABLE WHEN WALKING AND PERFORMING A SECONDARY TASK? EXAMINATION OF ATTENTIONAL SWITCHING ABILITIES

PubMed Central

Hawkes, Teresa D; Siu, Ka-Chun; Silsupadol, Patima; Woollacott, Marjorie H.

2011-01-01

Previous research using dual-task paradigms indicates balance-impaired older adults (BIOA) are less able to flexibly shift attentional focus between a cognitive and motor task than healthy older adults (HOA). Shifting attention is a component of executive function. Task switch tests assess executive attention function. This multivariate study asked if BIOAs demonstrate greater task switching deficits than HOAs. A group of 39 HOA (65–80 yrs) and BIOA (65–87 yrs) subjects performed a visuo-spatial task switch. A sub-group of subjects performed a dual-task obstacle avoidance paradigm. All participants completed the Berg Balance Scale (BBS) and Timed Up and Go (TUG). We assessed differences by group for: 1) visuo-spatial task switch reaction times (switch/no-switch), and performance on the BBS and TUG. Our balance groups differed significantly on BBS score (p < .001) and switch reaction time (p = .032), but not the TUG. This confirmed our hypothesis that neuromuscular and executive attention function differs between these two groups. For our BIOA sub-group, gait velocity correlated negatively with performance on the switch condition (p=.036). This suggests that BIOA efficiency of attentional allocation in dual task settings should be further explored. PMID:21964051

Measuring the effects of a visual or auditory Stroop task on dual-task costs during obstacle crossing.

PubMed

Worden, Timothy A; Mendes, Matthew; Singh, Pratham; Vallis, Lori Ann

2016-10-01

Successful planning and execution of motor strategies while concurrently performing a cognitive task has been previously examined, but unfortunately the varied and numerous cognitive tasks studied has limited our fundamental understanding of how the central nervous system successfully integrates and executes these tasks simultaneously. To gain a better understanding of these mechanisms we used a set of cognitive tasks requiring similar central executive function processes and response outputs but requiring different perceptual mechanisms to perform the motor task. Thirteen healthy young adults (20.6±1.6years old) were instrumented with kinematic markers (60Hz) and completed 5 practice, 10 single-task obstacle walking trials and two 40 trial experimental blocks. Each block contained 20 trials of seated (single-task) trials followed by 20 cognitive and obstacle (30% lower leg length) crossing trials (dual-task). Blocks were randomly presented and included either an auditory Stroop task (AST; central interference only) or a visual Stroop task (VST; combined central and structural interference). Higher accuracy rates and shorter response times were observed for the VST versus AST single-task trials (p<0.05). Conversely, for the obstacle stepping performance, larger dual task costs were observed for the VST as compared to the AST for clearance measures (the VST induced larger clearance values for both the leading and trailing feet), indicating VST tasks caused greater interference for obstacle crossing (p<0.05). These results supported the hypothesis that structural interference has a larger effect on motor performance in a dual-task situation compared to cognitive tasks that pose interference at only the central processing stage. Copyright © 2016 Elsevier B.V. All rights reserved.

Rivastigmine for gait stability in patients with Parkinson's disease (ReSPonD): a randomised, double-blind, placebo-controlled, phase 2 trial.

PubMed

Henderson, Emily J; Lord, Stephen R; Brodie, Matthew A; Gaunt, Daisy M; Lawrence, Andrew D; Close, Jacqueline C T; Whone, A L; Ben-Shlomo, Y

2016-03-01

Falls are a frequent and serious complication of Parkinson's disease and are related partly to an underlying cholinergic deficit that contributes to gait and cognitive dysfunction in these patients. Gait dysfunction can lead to an increased variability of gait from one step to another, raising the likelihood of falls. In the ReSPonD trial we aimed to assess whether ameliorating this cholinergic deficit with the acetylcholinesterase inhibitor rivastigmine would reduce gait variability. We did this randomised, double-blind, placebo-controlled, phase 2 trial at the North Bristol NHS Trust Hospital, Bristol, UK, in patients with Parkinson's disease recruited from community and hospital settings in the UK. We included patients who had fallen at least once in the year before enrolment, were able to walk 18 m without an aid, had no previous exposure to an acetylcholinesterase inhibitor, and did not have dementia. Our clinical trials unit randomly assigned (1:1) patients to oral rivastigmine or placebo capsules (both taken twice a day) using a computer-generated randomisation sequence and web-based allocation. Rivastigmine was uptitrated from 3 mg per day to the target dose of 12 mg per day over 12 weeks. Both the trial team and patients were masked to treatment allocation. Masking was achieved with matched placebo capsules and a dummy uptitration schedule. The primary endpoint was difference in step time variability between the two groups at 32 weeks, adjusted for baseline age, cognition, step time variability, and number of falls in the previous year. We measured step time variability with a triaxial accelerometer during an 18 m walking task in three conditions: normal walking, simple dual task with phonemic verbal fluency (walking while naming words beginning with a single letter), and complex dual task switching with phonemic verbal fluency (walking while naming words, alternating between two letters of the alphabet). Analysis was by modified intention to treat; we excluded from the primary analysis patients who withdrew, died, or did not attend the 32 week assessment. This trial is registered with ISRCTN, number 19880883. Between Oct 4, 2012 and March 28, 2013, we enrolled 130 patients and randomly assigned 65 to the rivastigmine group and 65 to the placebo group. At week 32, compared with patients assigned to placebo (59 assessed), those assigned to rivastigmine (55 assessed) had improved step time variability for normal walking (ratio of geometric means 0.72, 95% CI 0.58-0.88; p=0.002) and the simple dual task (0.79; 0.62-0.99; p=0.045). Improvements in step time variability for the complex dual task did not differ between groups (0.81, 0.60-1.09; p=0.17). Gastrointestinal side-effects were more common in the rivastigmine group than in the placebo group (p<0.0001); 20 (31%) patients in the rivastigmine group versus three (5%) in the placebo group had nausea and 15 (17%) versus three (5%) had vomiting. Rivastigmine can improve gait stability and might reduce the frequency of falls. A phase 3 study is needed to confirm these findings and show cost-effectiveness of rivastigmine treatment. Parkinson's UK. Copyright © 2016 Henderson et al. Open Access article distributed under the terms of CC BY. Published by Elsevier Ltd.. All rights reserved.

Biomechanical Analyses of Stair-climbing while Dual-tasking

PubMed Central

Vallabhajosula, Srikant; Tan, Chi Wei; Mukherjee, Mukul; Davidson, Austin J.; Stergiou, Nicholas

2015-01-01

Stair-climbing while doing a concurrent task like talking or holding an object is a common activity of daily living which poses high risk for falls. While biomechanical analyses of overground walking during dual-tasking have been studied extensively, little is known on the biomechanics of stair-climbing while dual-tasking. We sought to determine the impact of performing a concurrent cognitive or motor task during stair-climbing. We hypothesized that a concurrent cognitive task will have a greater impact on stair climbing performance compared to a concurrent motor task and that this impact will be greater on a higher-level step. Ten healthy young adults performed 10 trials of stair-climbing each under four conditions: stair ascending only, stair ascending and performing subtraction of serial sevens from a three-digit number, stair ascending and carrying an empty opaque box and stair ascending, performing subtraction of serial sevens from a random three-digit number and carrying an empty opaque box. Kinematics (lower extremity joint angles and minimum toe clearance) and kinetics (ground reaction forces and joint moments and powers) data were collected. We found that a concurrent cognitive task impacted kinetics but not kinematics of stair-climbing. The effect of dual-tasking during stair ascent also seemed to vary based on the different phases of stair ascent stance and seem to have greater impact as one climbs higher. Overall, the results of the current study suggest that the association between the executive functioning and motor task (like gait) becomes stronger as the level of complexity of the motor task increases. PMID:25773590

The feasibility of singing to improve gait in Parkinson disease

PubMed Central

Harrison, Elinor C.; McNeely, Marie E.; Earhart, Gammon M.

2017-01-01

Brain regions important for controlling movement are also responsible for rhythmic processing. In Parkinson disease (PD), defective internal timing within the brain has been linked to impaired beat discrimination, and may contribute to a loss of ability to maintain a steady gait rhythm. Less rhythmic gait is inherently less efficient, and this may lead to gait impairment including reduced speed, cadence, and stride length, as well as increased variability. While external rhythmic auditory stimulation (e.g. a metronome beat) is well-established as an effective tool to stabilize gait in PD, little is known about whether self-generated cues such as singing have the same beneficial effect on gait in PD. Thus, we compared gait patterns of 23 people with mild to moderate PD under five cued conditions: uncued, music only, singing only, singing with music, and a verbal dual-task condition. In our single session study, singing while walking did not significantly alter velocity, cadence, or stride length, indicating that it was not excessively demanding for people with PD. In addition, walking was less variable when singing than during other cued conditions. This was further supported by the comparison between singing trials and a verbal dual-task condition. In contrast to singing, the verbal dual-task negatively affected gait performance. These findings suggest that singing holds promise as an effective cueing technique that may be as good as or better than traditional cueing techniques for improving gait among people with PD. PMID:28226309

The feasibility of singing to improve gait in Parkinson disease.

PubMed

Harrison, Elinor C; McNeely, Marie E; Earhart, Gammon M

2017-03-01

Brain regions important for controlling movement are also responsible for rhythmic processing. In Parkinson disease (PD), defective internal timing within the brain has been linked to impaired beat discrimination, and may contribute to a loss of ability to maintain a steady gait rhythm. Less rhythmic gait is inherently less efficient, and this may lead to gait impairment including reduced speed, cadence, and stride length, as well as increased variability. While external rhythmic auditory stimulation (e.g. a metronome beat) is well-established as an effective tool to stabilize gait in PD, little is known about whether self-generated cues such as singing have the same beneficial effect on gait in PD. Thus, we compared gait patterns of 23 people with mild to moderate PD under five cued conditions: uncued, music only, singing only, singing with music, and a verbal dual-task condition. In our single-session study, singing while walking did not significantly alter velocity, cadence, or stride length, indicating that it was not excessively demanding for people with PD. In addition, walking was less variable when singing than during other cued conditions. This was further supported by the comparison between singing trials and a verbal dual-task condition. In contrast to singing, the verbal dual-task negatively affected gait performance. These findings suggest that singing holds promise as an effective cueing technique that may be as good as or better than traditional cueing techniques for improving gait among people with PD. Copyright © 2017 Elsevier B.V. All rights reserved.

Saccade frequency response to visual cues during gait in Parkinson's disease: the selective role of attention.

PubMed

Stuart, Samuel; Lord, Sue; Galna, Brook; Rochester, Lynn

2018-04-01

Gait impairment is a core feature of Parkinson's disease (PD) with implications for falls risk. Visual cues improve gait in PD, but the underlying mechanisms are unclear. Evidence suggests that attention and vision play an important role; however, the relative contribution from each is unclear. Measurement of visual exploration (specifically saccade frequency) during gait allows for real-time measurement of attention and vision. Understanding how visual cues influence visual exploration may allow inferences of the underlying mechanisms to response which could help to develop effective therapeutics. This study aimed to examine saccade frequency during gait in response to a visual cue in PD and older adults and investigate the roles of attention and vision in visual cue response in PD. A mobile eye-tracker measured saccade frequency during gait in 55 people with PD and 32 age-matched controls. Participants walked in a straight line with and without a visual cue (50 cm transverse lines) presented under single task and dual-task (concurrent digit span recall). Saccade frequency was reduced when walking in PD compared to controls; however, visual cues ameliorated saccadic deficit. Visual cues significantly increased saccade frequency in both PD and controls under both single task and dual-task. Attention rather than visual function was central to saccade frequency and gait response to visual cues in PD. In conclusion, this study highlights the impact of visual cues on visual exploration when walking and the important role of attention in PD. Understanding these complex features will help inform intervention development. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Transfer effects of fall training on balance performance and spatiotemporal gait parameters in healthy community-dwelling older adults: a pilot study.

PubMed

Donath, Lars; Faude, Oliver; Bridenbaugh, Stephanie A; Roth, Ralf; Soltermann, Martin; Kressig, Reto W; Zahner, Lukas

2014-07-01

This study examined transfer effects of fall training on fear of falling (Falls Efficacy Scale-International [FES-I]), balance performance, and spatiotemporal gait characteristics in older adults. Eighteen community-dwelling older adults (ages 65-85) were randomly assigned to an intervention or control group. The intervention group completed 12 training sessions (60 min, 6 weeks). During pre- and posttesting, we measured FES-I, balance performance (double limb, closed eyes; single limb, open eyes; double limb, open eyes with motor-interfered task), and gait parameters (e.g., velocity; cadence; stride time, stride width, and stride length; variability of stride time and stride length) under single- and motor-interfered tasks. Dual tasks were applied to appraise improvements of cognitive processing during balance and gait. FES-I (p = .33) and postural sway did not significantly change (0.36 < p < .79). Trends toward significant interaction effects were found for step width during normal walking and stride length variability during the motor dual task (p = .05, ηp 2 = .22). Fall training did not sufficiently improve fear of falling, balance, or gait performance under single- or dual-task conditions in healthy older adults.

Efficacy of an Exercise Game Based on Kinect in Improving Physical Performances of Fall Risk Factors in Community-Dwelling Older Adults.

PubMed

Kayama, Hiroki; Okamoto, Kazuya; Nishiguchi, Shu; Yukutake, Taiki; Tanigawa, Takanori; Nagai, Koutatsu; Yamada, Minoru; Aoyama, Tomoki

2013-08-01

The purpose of this study was to demonstrate whether a 12-week program of training with dual-task Tai Chi (DTTC), which is a new concept game we developed using Kinect (Microsoft, Redmond, WA), would be effective in improving physical functions of fall risk factors. This study examined balance, muscle strength, locomotive ability, and dual-task ability in community-dwelling older adults (75.4±6.3 years) before and after 12 weeks of DTTC training (training group [TG]; n=32) or standardized training (control group [CG]; n=41). Primary end points were based on the difference in physical functions between the TG and the CG. Significant differences were observed between the two groups with significant group×time interaction for the following physical function measures: timed up-and-go (TUG) (P<0.01), one-leg standing (OLS) (P<0.05), and 5 chair stand (5-CS) (P<0.05). There were no significant differences among the other measures: 10-m walking time under standard conditions, manual-task conditions, and cognitive-task conditions, 10-m maximal walking time, and Functional Reach test scores. Thus, the scores of TUG, OLS, and 5-CS in the TG improved significantly with DTTC training compared with the CG. The results suggest that the DTTC training is effective in improving balance ability and mobility, which are risk factors for falls.

Gait Adaptability Training Improves Both Postural Stability and Dual-Tasking Ability

NASA Technical Reports Server (NTRS)

Brady, Rachel A.; Batson, Crystal D.; Peters, Brian T.; Ploutz-Snyder, Robert J.; Mulavara, Ajitkumar P.; Bloomberg, Jacob J.

2010-01-01

After spaceflight, the process of readapting to Earth's gravity commonly presents crewmembers with a variety of locomotor challenges. Our recent work has shown that the ability to adapt to a novel discordant sensorimotor environment can be increased through preflight training, so one focus of our laboratory has been the development of a gait training countermeasure to expedite the return of normal locomotor function after spaceflight. We used a training system comprising a treadmill mounted on a motion base facing a virtual visual scene that provided a variety of sensory challenges. As part of their participation in a larger retention study, 10 healthy adults completed 3 training sessions during which they walked on a treadmill at 1.1 m/s while receiving discordant support-surface and visual manipulations. After a single training session, subjects stride frequencies improved, and after 2 training sessions their auditory reaction times improved, where improvement was indicated by a return toward baseline values. Interestingly, improvements in reaction time came after stride frequency improvements plateaued. This finding suggests that postural stability was given a higher priority than a competing cognitive task. Further, it demonstrates that improvement in both postural stability and dual-tasking can be achieved with multiple training exposures. We conclude that, with training, individuals become more proficient at walking in discordant sensorimotor conditions and are able to devote more attention to competing tasks.

Talking while walking: Cognitive loading and injurious falls in Parkinson's disease.

PubMed

LaPointe, Leonard L; Stierwalt, Julie A G; Maitland, Charles G

2010-10-01

Multitasking has become a way of life, from operating multiple software packages simultaneously on a computer, to carrying on a conversation on a cell phone while driving. Perhaps one of the most common dual tasks performed is talking while walking. In isolation, neither task would be considered difficult to perform, yet when coupled, the relative ease of each task may change. This paper details significant problems that result from injurious falls, and points out the vulnerability of those who have been diagnosed with Parkinson's disease. In addition, it provides an illustrative study that demonstrates the potential danger of talking while walking, especially when the cognitive-linguistic complexity of verbal tasks is manipulated. In this investigation, 25 participants with Parkinson's disease and 13 participants without neurological compromise completed gait tasks while conducting tasks of low (counting by ones), middle (serial subtraction of threes), and high load (alpha-numeric sequencing). The results indicated that cognitive-linguistic demand had an impact on gait, the effects of which were demonstrated in individuals without neurological compromise as well as those with Parkinson's disease. One finding, altered double-support time, distinguished the Parkinson group from the control participants. These results suggest that it might be prudent for healthcare professionals and caregivers to alter expectations and monitor the cognitive-linguistic demands placed on elderly individuals, particularly those with neurological compromise who might be at greater risk for injurious falls.

Effect of smart phone use on dynamic postural balance.

PubMed

Cho, Sung-Hak; Choi, Mun-Hee; Goo, Bong-Oh

2014-07-01

[Purpose] The present study investigated what kind of effect smart phone use has on dynamic postural balance. [Subjects] The study subjects were 30 healthy students in their 20's who were recruited from a University in Busan, Korea. [Methods] The present experiment was quasi-experimental research which measured the postural balance (Biodex) of subjects while they sent text messages via smart phones in the standing position with the eyes open, and while they used two-way SNS. [Results] There were significant differences between standing and the dual-task situations. Among dual tasks using smart phones, SNS using situations showed the highest instability. [Conclusion] The use of smart phones in less stable conditions such as while walking or in moving vehicles should be discouraged.

Laboratory review: the role of gait analysis in seniors' mobility and fall prevention.

PubMed

Bridenbaugh, Stephanie A; Kressig, Reto W

2011-01-01

Walking is a complex motor task generally performed automatically by healthy adults. Yet, by the elderly, walking is often no longer performed automatically. Older adults require more attention for motor control while walking than younger adults. Falls, often with serious consequences, can be the result. Gait impairments are one of the biggest risk factors for falls. Several studies have identified changes in certain gait parameters as independent predictors of fall risk. Such gait changes are often too discrete to be detected by clinical observation alone. At the Basel Mobility Center, we employ the GAITRite electronic walkway system for spatial-temporal gait analysis. Although we have a large range of indications for gait analyses and several areas of clinical research, our focus is on the association between gait and cognition. Gait analysis with walking as a single-task condition alone is often insufficient to reveal underlying gait disorders present during normal, everyday activities. We use a dual-task paradigm, walking while simultaneously performing a second cognitive task, to assess the effects of divided attention on motor performance and gait control. Objective quantification of such clinically relevant gait changes is necessary to determine fall risk. Early detection of gait disorders and fall risk permits early intervention and, in the best-case scenario, fall prevention. We and others have shown that rhythmic movement training such as Jaques-Dalcroze eurhythmics, tai chi and social dancing can improve gait regularity and automaticity, thus increasing gait safety and reducing fall risk. Copyright © 2010 S. Karger AG, Basel.

Application of the clinical version of the narrow path walking test to identify elderly fallers.

PubMed

Gimmon, Yoav; Barash, Avi; Debi, Ronen; Snir, Yoram; Bar David, Yair; Grinshpon, Jacob; Melzer, Itshak

2016-01-01

Falling during walking is a common problem among the older population. Hence, the challenge facing clinicians is identifying who is at risk of falling during walking, for providing an effective intervention to reduce that risk. We aimed to assess whether the clinical version of the narrow path walking test (NPWT) could identify older adults who are reported falls. A total of 160 older adults were recruited and asked to recall fall events during the past year. Subjects were instructed to walk in the laboratory at a comfortable pace within a 6 meter long narrow path, 3 trials under single task (ST) and 3 trials dual task (DT) conditions without stepping outside the path (i.e., step errors). The average trial time, number of steps, trial velocity, number of step errors, and number of cognitive task errors were calculated for ST and DT. Fear of falling, performance oriented mobility assessment (POMA) and mini-metal state examination (MMSE) were measured as well. Sixty-one subjects reported that they had fallen during the past year and 99 did not. Fallers performed more steps, and were slower than non-fallers. There were no significant differences, however, in the number of steps errors, the cognitive task errors in ST and DT in POMA and MMSE. Our data demonstrates slower gait speed and more steps during the NPWT in ST and DT in fallers. There is no added value of DT over the ST for identification of faller's older adults. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Gait characteristics and their discriminative power in geriatric patients with and without cognitive impairment.

PubMed

Kikkert, Lisette H J; Vuillerme, Nicolas; van Campen, Jos P; Appels, Bregje A; Hortobágyi, Tibor; Lamoth, Claudine J C

2017-08-15

A detailed gait analysis (e.g., measures related to speed, self-affinity, stability, and variability) can help to unravel the underlying causes of gait dysfunction, and identify cognitive impairment. However, because geriatric patients present with multiple conditions that also affect gait, results from healthy old adults cannot easily be extrapolated to geriatric patients. Hence, we (1) quantified gait outcomes based on dynamical systems theory, and (2) determined their discriminative power in three groups: healthy old adults, geriatric patients with- and geriatric patients without cognitive impairment. For the present cross-sectional study, 25 healthy old adults recruited from community (65 ± 5.5 years), and 70 geriatric patients with (n = 39) and without (n = 31) cognitive impairment from the geriatric dayclinic of the MC Slotervaart hospital in Amsterdam (80 ± 6.6 years) were included. Participants walked for 3 min during single- and dual-tasking at self-selected speed while 3D trunk accelerations were registered with an IPod touch G4. We quantified 23 gait outcomes that reflect multiple gait aspects. A multivariate model was built using Partial Least Square- Discriminant Analysis (PLS-DA) that best modelled participant group from gait outcomes. For single-task walking, the PLS-DA model consisted of 4 Latent Variables that explained 63 and 41% of the variance in gait outcomes and group, respectively. Outcomes related to speed, regularity, predictability, and stability of trunk accelerations revealed with the highest discriminative power (VIP > 1). A high proportion of healthy old adults (96 and 93% for single- and dual-task, respectively) was correctly classified based on the gait outcomes. The discrimination of geriatric patients with and without cognitive impairment was poor, with 57% (single-task) and 64% (dual-task) of the patients misclassified. While geriatric patients vs. healthy old adults walked slower, and less regular, predictable, and stable, we found no differences in gait between geriatric patients with and without cognitive impairment. The effects of multiple comorbidities on geriatric patients' gait possibly causes a 'floor-effect', with no room for further deterioration when patients develop cognitive impairment. An accurate identification of cognitive status thus necessitates a multifactorial approach.

Posture and cognition in the elderly: interaction and contribution to the rehabilitation strategies.

PubMed

Borel, L; Alescio-Lautier, B

2014-01-01

In this paper we review the effects of aging on sensory systems and their impact on posture, balance and gait. We also address cognitive aging and attempt to specify which altered cognitive functions negatively impact balance and walking. The role of cognition in postural control is tested with dual-task experiments. This situation results in deleterious effects due to an attentional overload. Given the human cognitive system has limited capacities, we propose that simultaneously performing two tasks depends on the capacity of each individual to perform these tasks on a continuum between automatic execution to highly controlled performance. A level of maximum control exceeds the subject's attentional capacity, which makes it impossible to perform both tasks simultaneously. The subject therefore prioritizes one of the tasks. We use representative dual-task studies from the literature to illustrate the relationship between the different cognitive components and their impact on the control of posture and gait in elderly subjects with altered cognitive capacities and with elderly subjects who are fallers or who have altered sensory-motor capacities. Recently this postural-cognitive relationship was addressed with a new approach. We report how cognitive training can improve dual-task management and we attempt to define the cognitive mechanisms that may be responsible for better postural balance. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Gaze shifts during dual-tasking stair descent.

PubMed

Miyasike-daSilva, Veronica; McIlroy, William E

2016-11-01

To investigate the role of vision in stair locomotion, young adults descended a seven-step staircase during unrestricted walking (CONTROL), and while performing a concurrent visual reaction time (RT) task displayed on a monitor. The monitor was located at either 3.5 m (HIGH) or 0.5 m (LOW) above ground level at the end of the stairway, which either restricted (HIGH) or facilitated (LOW) the view of the stairs in the lower field of view as participants walked downstairs. Downward gaze shifts (recorded with an eye tracker) and gait speed were significantly reduced in HIGH and LOW compared with CONTROL. Gaze and locomotor behaviour were not different between HIGH and LOW. However, inter-individual variability increased in HIGH, in which participants combined different response characteristics including slower walking, handrail use, downward gaze, and/or increasing RTs. The fastest RTs occurred in the midsteps (non-transition steps). While gait and visual task performance were not statistically different prior to the top and bottom transition steps, gaze behaviour and RT were more variable prior to transition steps in HIGH. This study demonstrated that, in the presence of a visual task, people do not look down as often when walking downstairs and require minimum adjustments provided that the view of the stairs is available in the lower field of view. The middle of the stairs seems to require less from executive function, whereas visual attention appears a requirement to detect the last transition via gaze shifts or peripheral vision.

Cognitive demand and predictive adaptational responses in dynamic stability control.

PubMed

Bohm, Sebastian; Mersmann, Falk; Bierbaum, Stefanie; Dietrich, Ralf; Arampatzis, Adamantios

2012-09-21

We studied the effects of a concurrent cognitive task on predictive motor control, a feedforward mechanism of dynamic stability control, during disturbed gait in young and old adults. Thirty-two young and 27 elderly male healthy subjects participated and were randomly assigned to either control or dual task groups. By means of a covered exchangeable element the surface condition on a gangway could be altered to induce gait perturbations. The experimental protocol included a baseline on hard surface and an adaptation phase with twelve trials on soft surface. After the first, sixth and last soft surface trial, the surface condition was changed to hard (H1-3), to examine after-effects and, thus, to quantify predictive motor control. Dynamic stability was assessed using the 'margin of stability (MoS)' as a criterion for the stability state of the human body (extrapolated center of mass concept). In H1-3 the young participants significantly increased the MoS at touchdown of the disturbed leg compared to baseline. The magnitude and the rate of these after-effects were unaffected by the dual task condition. The old participants presented a trend to after-effects (i.e., increase of MoS) in H3 but only under the dual task condition.In conclusion, the additional cognitive demand did not compromise predictive motor control during disturbed walking in the young and old participants. In contrast to the control group, the old dual task group featured a trend to predictive motor adjustments, which may be a result of a higher state of attention or arousal due to the dual task paradigm. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Association of Clinic-Based Mobility Tasks and Measures of Community Performance and Risk.

PubMed

Callisaya, Michele L; Verghese, Joe

2018-01-10

Gait speed is recognized as an important predictor of adverse outcomes in older people. However, it is unknown whether other more complex mobility tasks are better predictors of such outcomes. To examine a range of clinic-based mobility tests and determine which were most strongly associated with measures of community performance and risk (CP&R). Cross-sectional study. Central Control Mobility and Aging Study, Westchester County, New York. Aged ≥65 years (n = 424). Clinic-based mobility measures included gait speed measured during normal and dual-task conditions, the Floor Maze Immediate and Delay tasks, and stair ascending and descending. CP&R measures were self-reported by the use of standardized questionnaires and classified into measures of performance (distance walked, travel outside one's home [life space], activities of daily living, and participation in cognitive leisure activities) or risk (balance confidence, fear of falling, and past falls). Linear and logistic regression were used to examine associations between the clinic-based mobility measures and CP&R measures adjusting for covariates. The mean age of the sample was 77.8 (SD 6.4) years, and 55.2% (n = 234) were female. In final models, faster normal walking speed was most strongly associated with 5 of the 7 community measures (greater distance walked, greater life space, better activities of daily living function, higher balance confidence, and less fear of falling; all P < .05). More complex tasks (walking while talking and maze immediate) were associated with cognitive leisure activity (P < .05), and ascending stairs was the only measure associated with a history of falls (P < .05). Normal walking speed is a simple and inexpensive clinic-based mobility test that is associated with a wide range of CP&R measures. In addition, poorer performance ascending stairs may assist in identifying those at risk of falls. Poorer performance in more complex mobility tasks (walking while talking and maze immediate) may suggest inability to participate in cognitive leisure activities. III. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Effects of simultaneously performed cognitive and physical training in older adults

PubMed Central

2013-01-01

Background While many studies confirm the positive effect of cognitive and physical training on cognitive performance of older adults, only little is known about the effects of simultaneously performed cognitive and physical training. In the current study, older adults simultaneously performed a verbal working memory and a cardiovascular training to improve cognitive and motor-cognitive dual task performance. Twenty training sessions of 30 minutes each were conducted over a period of ten weeks, with a test session before, in the middle, and after the training. Training gains were tested in measures of selective attention, paired-associates learning, executive control, reasoning, memory span, information processing speed, and motor-cognitive dual task performance in the form of walking and simultaneously performing a working memory task. Results Sixty-three participants with a mean age of 71.8 ± 4.9 years (range 65 to 84) either performed the simultaneous training (N = 21), performed a single working memory training (N = 16), or attended no training at all (N = 26). The results indicate similar training progress and larger improvements in the executive control task for both training groups when compared to the passive control group. In addition, the simultaneous training resulted in larger improvements compared to the single cognitive training in the paired-associates task and was able to reduce the step-to-step variability during the motor-cognitive dual task when compared to the single cognitive training and the passive control group. Conclusions The simultaneous training of cognitive and physical abilities presents a promising training concept to improve cognitive and motor-cognitive dual task performance, offering greater potential on daily life functioning, which usually involves the recruitment of multiple abilities and resources rather than a single one. PMID:24053148

Prefrontal Hemodynamics of Physical Activity and Environmental Complexity During Cognitive Work.

PubMed

McKendrick, Ryan; Mehta, Ranjana; Ayaz, Hasan; Scheldrup, Melissa; Parasuraman, Raja

2017-02-01

The aim of this study was to assess performance and cognitive states during cognitive work in the presence of physical work and in natural settings. Authors of previous studies have examined the interaction between cognitive and physical work, finding performance decrements in working memory. Neuroimaging has revealed increases and decreases in prefrontal oxygenated hemoglobin during the interaction of cognitive and physical work. The effect of environment on cognitive-physical dual tasking has not been previously considered. Thirteen participants were monitored with wireless functional near-infrared spectroscopy (fNIRS) as they performed an auditory 1-back task while sitting, walking indoors, and walking outdoors. Relative to sitting and walking indoors, auditory working memory performance declined when participants were walking outdoors. Sitting during the auditory 1-back task increased oxygenated hemoglobin and decreased deoxygenated hemoglobin in bilateral prefrontal cortex. Walking reduced the total hemoglobin available to bilateral prefrontal cortex. An increase in environmental complexity reduced oxygenated hemoglobin and increased deoxygenated hemoglobin in bilateral prefrontal cortex. Wireless fNIRS is capable of monitoring cognitive states in naturalistic environments. Selective attention and physical work compete with executive processing. During executive processing loading of selective attention and physical work results in deactivation of bilateral prefrontal cortex and degraded working memory performance, indicating that physical work and concomitant selective attention may supersede executive processing in the distribution of mental resources. This research informs decision-making procedures in work where working memory, physical activity, and attention interact. Where working memory is paramount, precautions should be taken to eliminate competition from physical work and selective attention.

Brain activation changes during locomotion in middle-aged to older adults with multiple sclerosis.

PubMed

Hernandez, Manuel E; Holtzer, Roee; Chaparro, Gioella; Jean, Kharine; Balto, Julia M; Sandroff, Brian M; Izzetoglu, Meltem; Motl, Robert W

2016-11-15

Mobility and cognitive impairments are common in persons with multiple sclerosis (MS), and are expected to worsen with increasing age. However, no studies, to date, in part due to limitations of conventional neuroimaging methods, have examined changes in brain activation patterns during active locomotion in older patients with MS. This study used functional Near Infrared Spectroscopy (fNIRS) to evaluate real-time neural activation differences in the pre-frontal cortex (PFC) between middle-aged to older adults with MS and healthy controls during single (Normal Walk; NW) and dual-task (Walking While Talking; WWT) locomotion tasks. Eight middle-aged to older adults with MS and eight healthy controls underwent fNIRS recording while performing the NW and WWT tasks with an fNIRS cap consisting of 16 optodes positioned over the forehead. The MS group had greater elevations in PFC oxygenation levels during WWT compared to NW than healthy controls. There was no walking performance difference between groups during locomotion. These findings suggest that middle-aged to older individuals with MS might be able to achieve similar levels of performance through the use of increased brain activation. This study is the first to investigate brain activation changes during the performance of simple and divided-attention locomotion tasks in MS using fNIRS. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of tetrahydrocannabinol on balance and gait in patients with dementia: A randomised controlled crossover trial.

PubMed

van den Elsen, Geke Ah; Tobben, Lieke; Ahmed, Amir Ia; Verkes, Robbert Jan; Kramers, Cornelis; Marijnissen, Radboud M; Olde Rikkert, Marcel Gm; van der Marck, Marjolein A

2017-02-01

Oral tetrahydrocannabinol (THC) is currently studied for its possible efficacy on dementia-related neuropsychiatric symptoms (NPS), but might lead to increased risk of falling. This was a randomised, double-blind, crossover study to evaluate the effects of THC on mobility in dementia patients. Eighteen community-dwelling patients ( M age =77 years) received 1.5 mg of oral THC twice daily and placebo, in random order, for three days, separated by a four-day washout. Balance and gait were assessed using SwayStar TM and GAITRite TM within two hours after administration, in two consecutive intervention periods, under the following conditions: standing with eyes open (EO) and eyes closed (EC), preferred speed walking with and without a cognitive dual task. THC significantly increased sway during standing EC (roll angle 0.32[±0.6]°, p=0.05; pitch angle 1.04[±1.5]°, p=0.009; pitch velocity 1.96[±3.3]°/s, p=0.02), but not during standing EO. During preferred speed walking, THC increased stride length (4.3[±5.4] cm, p=0.005) and trunk sway (pitch angle 1.18[±1.6]°, p=0.005). No effects were observed during dual task walking. No differences in the number and type of adverse events were found, and no falls occurred after administration of THC. This study showed that 3 mg of THC per day has a benign adverse event profile regarding mobility and was well tolerated by community-dwelling dementia patients.

Agile and dexterous robot for inspection and EOD operations

NASA Astrophysics Data System (ADS)

Handelman, David A.; Franken, Gordon H.; Komsuoglu, Haldun

2010-04-01

The All-Terrain Biped (ATB) robot is an unmanned ground vehicle with arms, legs and wheels designed to drive, crawl, walk and manipulate objects for inspection and explosive ordnance disposal tasks. This paper summarizes on-going development of the ATB platform. Control technology for semi-autonomous legged mobility and dual-arm dexterity is described as well as preliminary simulation and hardware test results. Performance goals include driving on flat terrain, crawling on steep terrain, walking on stairs, opening doors and grasping objects. Anticipated benefits of the adaptive mobility and dexterity of the ATB platform include increased robot agility and autonomy for EOD operations, reduced operator workload and reduced operator training and skill requirements.

Challenging gait leads to stronger lower-limb kinematic synergies: The effects of walking within a more narrow pathway.

PubMed

Rosenblatt, N J; Latash, M L; Hurt, C P; Grabiner, M D

2015-07-23

Previous studies using the uncontrolled manifold (UCM) analysis demonstrated that during the swing phase of gait, multi-joint kinematic synergies act to stabilize, i.e., minimize the variance of, the mediolateral trajectory of the swinging limb. Importantly, these synergies are strongest during midswing, suggesting that during gait, individuals may employ strategies to avoid collisions between the limbs at this instance. The purpose of the current study was to test this hypothesis by quantifying whether the synergy index (ΔV) during the middle period of the swing phase of treadmill walking was affected when the width of the treadmill belt was narrowed, a task expected to increase the risk of limb collisions. Eleven healthy young adults walked on a dual-belt treadmill under two conditions: (1) dual-belt - both belts of the treadmill moved at 1.2 m/s (total width: 62.5 cm) and the subject walked with one foot on each of the moving belts and (2) single-belt - one treadmill belt moved at 1.2m/s while the other belt remained stationary and the subject walked with both feet on the moving belt (total width: 30.5 cm). During both conditions, motion capture recorded the positions of 22 passive reflective markers from which UCM analysis was used to quantify ΔV in the joint configuration space. Results indicate that ΔV during the middle-third of swing phase significantly increased by 20% during single-belt walking (p<.01). We interpret this as evidence that the stronger synergies at midswing are needed to stabilize the limb trajectory in order to reduce the risk of between-limb collisions during a period when the lower limbs are nearest each other in the frontal plane. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The effect of rhythmic musical training on healthy older adults' gait and cognitive function.

PubMed

Maclean, Linda M; Brown, Laura J E; Astell, Arlene J

2014-08-01

Older adults' gait is disturbed when a demanding secondary cognitive task is added. Gait training has been shown to improve older adults' walking performance, but it is not clear how training affects their cognitive performance. This study examined the impact on gait, in terms of cost or benefit to cognitive performance, of training healthy older adults to walk to a rhythmic musical beat. In a mixed model design, 45 healthy older adults aged more than 65 years (M = 71.7 years) were randomly assigned to 3 groups. One group received a rhythmic musical training and their dual-task (DT) walking and cognitive performances were compared with a group who had music playing in the background but no training, and a third group who heard no music and received no training. Outcomes in single-task (ST) and DT conditions were step-time variability and velocity for gait and correct cognitive responses for the cognitive task. The Musical Training group's step-time variability improved in both the ST (p < .05) and the DT (p < .05) after training, without adversely affecting their cognitive performance. No change was seen in the control groups. Rhythmic musical training can improve gait steadiness in healthy older adults with no negative impact on concurrent cognitive functioning. This could potentially enhance "postural reserve" and reduce fall risk. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The JFK BIG study: the impact of LSVT BIG® on dual task walking and mobility in persons with Parkinson's disease.

PubMed

Isaacson, Sara; O'Brien, Ashley; Lazaro, Jennifer D; Ray, Arlen; Fluet, Gerard

2018-04-01

[Purpose] The aim of this study was to test the hypothesis that Lee Silverman Voice Treatment-BIG decreases the negative impact of hypokinesia on dual task performance in persons with Parkinson's disease. [Subjects and Methods] The records of 114 patients with Parkinson's admitted to outpatient rehabilitation at a suburban hospital were reviewed. Demographics and data for 8 outcome measures were extracted for subjects that completed 14 of 16 sessions of BIG. 93 of these subjects had records of pre and post-test Timed Up and Go, Timed Up and Go Motor, and Timed Up and Go Cognitive scores. Average age was 68.4 years (SD=10.6) and average disease duration was 4.9 years (SD=5.3). [Results] Subjects demonstrated statistically significant improvements for Timed Up and Go (3.3 SD=4.5), Timed Up and Go Motor (4.4 SD=5.8) and Timed Up and Go Cognitive (4.7 SD=5.4). Concurrent motor and cognitive performance remained stable. Dual task cost decreased at a statistically significant level for Timed Up and Go Cognitive (7% SD=31%) but not Motor (4% SD=32%). [Conclusion] These findings suggest that cueing strategies associated with LSVT BIG become internalized and decrease the negative impact of hypokinesia on mobility and cognitive performance while performing two tasks simultaneously in persons with Parkinson's.

Performance of an attention-demanding task during treadmill walking shifts the noise qualities of step-to-step variation in step width.

PubMed

Grabiner, Mark D; Marone, Jane R; Wyatt, Marilynn; Sessoms, Pinata; Kaufman, Kenton R

2018-06-01

The fractal scaling evident in the step-to-step fluctuations of stepping-related time series reflects, to some degree, neuromotor noise. The primary purpose of this study was to determine the extent to which the fractal scaling of step width, step width and step width variability are affected by performance of an attention-demanding task. We hypothesized that the attention-demanding task would shift the structure of the step width time series toward white, uncorrelated noise. Subjects performed two 10-min treadmill walking trials, a control trial of undisturbed walking and a trial during which they performed a mental arithmetic/texting task. Motion capture data was converted to step width time series, the fractal scaling of which were determined from their power spectra. Fractal scaling decreased by 22% during the texting condition (p < 0.001) supporting the hypothesized shift toward white uncorrelated noise. Step width and step width variability increased 19% and five percent, respectively (p < 0.001). However, a stepwise discriminant analysis to which all three variables were input revealed that the control and dual task conditions were discriminated only by step width fractal scaling. The change of the fractal scaling of step width is consistent with increased cognitive demand and suggests a transition in the characteristics of the signal noise. This may reflect an important advance toward the understanding of the manner in which neuromotor noise contributes to some types of falls. However, further investigation of the repeatability of the results, the sensitivity of the results to progressive increases in cognitive load imposed by attention-demanding tasks, and the extent to which the results can be generalized to the gait of older adults seems warranted. Copyright © 2018 Elsevier B.V. All rights reserved.

Motor performance differentiates individuals with Lewy body dementia, Parkinson's and Alzheimer's disease.

PubMed

Fritz, Nora E; Kegelmeyer, Deborah A; Kloos, Anne D; Linder, Shannon; Park, Ariane; Kataki, Maria; Adeli, Anahita; Agrawal, Punit; Scharre, Douglas W; Kostyk, Sandra K

2016-10-01

Differential diagnosis of dementia with Lewy bodies (DLB), Parkinson's disease with dementia (PDD), Parkinson's disease (PD) and Alzheimer's disease (AD) is challenging. Comparative motor profiles of these neurodegenerative disorders may aid in earlier diagnosis but have not been extensively studied. Groups were rigorously matched by age, education, and sex. DLB/PDD participants were matched by Mini-Mental State Examination Score to individuals with AD and by Unified Parkinson's Disease Rating Scale motor scores to individuals with PD. Gait, balance, dual task walking and hand dexterity measures were compared between a combined group (n=21) of individuals with Lewy body dementia (LBD) consisting of those with DLB (n=11) and PDD (n=10) to individuals with PD (n=21) or AD (n=21). Individuals at the same disease stage with LBD walked significantly slower with shorter stride lengths (p<0.05), demonstrated poorer balance on both the Tinetti and Berg Balance Scale, and poorer performance on dual-task and figure-of-eight walking compared to PD and AD (p<0.05 for all) groups. Upper extremity coordination on the 9-hole peg test differentiated LBD from both PD and AD and was the only motor test in which individuals with AD performed worse than those with PD. Tinetti balance subscores were significantly lower in PDD compared to DLB participants (10.4±2.3 versus 12.8±2.3; p=0.027). Motor features distinguish individuals with LBD from those with AD and PD. Measures of gait, balance and finger dexterity provide an additional means of differentiating individuals with LBD from those with AD and PD. Copyright © 2016 Elsevier B.V. All rights reserved.

Direct and indirect effects of attention and visual function on gait impairment in Parkinson's disease: influence of task and turning.

PubMed

Stuart, Samuel; Galna, Brook; Delicato, Louise S; Lord, Sue; Rochester, Lynn

2017-07-01

Gait impairment is a core feature of Parkinson's disease (PD) which has been linked to cognitive and visual deficits, but interactions between these features are poorly understood. Monitoring saccades allows investigation of real-time cognitive and visual processes and their impact on gait when walking. This study explored: (i) saccade frequency when walking under different attentional manipulations of turning and dual-task; and (ii) direct and indirect relationships between saccades, gait impairment, vision and attention. Saccade frequency (number of fast eye movements per-second) was measured during gait in 60 PD and 40 age-matched control participants using a mobile eye-tracker. Saccade frequency was significantly reduced in PD compared to controls during all conditions. However, saccade frequency increased with a turn and decreased under dual-task for both groups. Poorer attention directly related to saccade frequency, visual function and gait impairment in PD, but not controls. Saccade frequency did not directly relate to gait in PD, but did in controls. Instead, saccade frequency and visual function deficit indirectly impacted gait impairment in PD, which was underpinned by their relationship with attention. In conclusion, our results suggest a vital role for attention with direct and indirect influences on gait impairment in PD. Attention directly impacted saccade frequency, visual function and gait impairment in PD, with connotations for falls. It also underpinned indirect impact of visual and saccadic impairment on gait. Attention therefore represents a key therapeutic target that should be considered in future research. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

The JFK BIG study: the impact of LSVT BIG® on dual task walking and mobility in persons with Parkinson’s disease

PubMed Central

Isaacson, Sara; O’Brien, Ashley; Lazaro, Jennifer D.; Ray, Arlen; Fluet, Gerard

2018-01-01

[Purpose] The aim of this study was to test the hypothesis that Lee Silverman Voice Treatment-BIG decreases the negative impact of hypokinesia on dual task performance in persons with Parkinson’s disease. [Subjects and Methods] The records of 114 patients with Parkinson’s admitted to outpatient rehabilitation at a suburban hospital were reviewed. Demographics and data for 8 outcome measures were extracted for subjects that completed 14 of 16 sessions of BIG. 93 of these subjects had records of pre and post-test Timed Up and Go, Timed Up and Go Motor, and Timed Up and Go Cognitive scores. Average age was 68.4 years (SD=10.6) and average disease duration was 4.9 years (SD=5.3). [Results] Subjects demonstrated statistically significant improvements for Timed Up and Go (3.3 SD=4.5), Timed Up and Go Motor (4.4 SD=5.8) and Timed Up and Go Cognitive (4.7 SD=5.4). Concurrent motor and cognitive performance remained stable. Dual task cost decreased at a statistically significant level for Timed Up and Go Cognitive (7% SD=31%) but not Motor (4% SD=32%). [Conclusion] These findings suggest that cueing strategies associated with LSVT BIG become internalized and decrease the negative impact of hypokinesia on mobility and cognitive performance while performing two tasks simultaneously in persons with Parkinson’s. PMID:29706722

Neural correlates of obstacle negotiation in older adults: An fNIRS study.

PubMed

Chen, Michelle; Pillemer, Sarah; England, Sarah; Izzetoglu, Meltem; Mahoney, Jeannette R; Holtzer, Roee

2017-10-01

Older adults are less efficient at avoiding obstacles compared to young adults, especially under attention-demanding conditions. Using functional near-infrared-spectroscopy (fNIRS), recent studies implicated the prefrontal cortex (PFC) in cognitive control of locomotion, notably under dual-task walking conditions. The neural substrates underlying Obstacle Negotiation (ON), however, have not been established. The current study determined the role of the PFC in ON during walking in seniors. Non-demented older adults (n=90; mean age=78.1±5.5years; %female=51) underwent fNIRS acquisition to assess changes in hemodynamic activity in the PFC during normal-walk [NW] and walk-while-talk [WWT] conditions with and without obstacles. Obstacles were presented as red elliptical shapes using advanced laser technology, which resemble potholes. Linear mixed effects models were used to determine differences in oxygenated hemoglobin (HbO 2 ) levels among the four task conditions. The presence of slow gait, a risk factor for dementia and falls, served as a predictor hypothesized to moderate the effect of obstacles on PFC HbO 2 levels. PFC HbO 2 levels were significantly higher in WWT compared to NW (p<0.001) irrespective of ON. Slow gait moderated the effect of obstacles on HbO 2 levels across task conditions. Specifically, compared to participants with normal gait, PFC HbO 2 levels were significantly increased in ON-NW relative to NW (p=0.017) and ON-WWT relative to WWT (p<0.001) among individuals with slow gait. Consistent with Compensatory Reallocation, ON required greater PFC involvement among individuals with mobility limitations. Copyright © 2017 Elsevier B.V. All rights reserved.

Training to Facilitate Adaptation to Novel Sensory Environments

NASA Technical Reports Server (NTRS)

Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. D.; Ploutz-Snyder, R. J.; Cohen, H. S.

2010-01-01

After spaceflight, the process of readapting to Earth s gravity causes locomotor dysfunction. We are developing a gait training countermeasure to facilitate adaptive responses in locomotor function. Our training system is comprised of a treadmill placed on a motion-base facing a virtual visual scene that provides an unstable walking surface combined with incongruent visual flow designed to train subjects to rapidly adapt their gait patterns to changes in the sensory environment. The goal of our present study was to determine if training improved both the locomotor and dual-tasking ability responses to a novel sensory environment and to quantify the retention of training. Subjects completed three, 30-minute training sessions during which they walked on the treadmill while receiving discordant support surface and visual input. Control subjects walked on the treadmill without any support surface or visual alterations. To determine the efficacy of training, all subjects were then tested using a novel visual flow and support surface movement not previously experienced during training. This test was performed 20 minutes, 1 week, and 1, 3, and 6 months after the final training session. Stride frequency and auditory reaction time were collected as measures of postural stability and cognitive effort, respectively. Subjects who received training showed less alteration in stride frequency and auditory reaction time compared to controls. Trained subjects maintained their level of performance over 6 months. We conclude that, with training, individuals became more proficient at walking in novel discordant sensorimotor conditions and were able to devote more attention to competing tasks.

Can Change in Prolonged Walking Be Inferred From a Short Test of Gait Speed Among Older Adults Who Are Initially Well-Functioning?

PubMed Central

Neogi, Tuhina; King, Wendy C.; LaValley, Michael P.; Kritchevsky, Stephen B.; Nevitt, Michael C.; Harris, Tamara B.; Ferrucci, Luigi; Simonsick, Eleanor M.; Satterfield, Suzanne; Strotmeyer, Elsa S.; Zhang, Yuqing

2014-01-01

Background The ability to walk for short and prolonged periods of time is often measured with separate walking tests. It is unclear whether decline in the 2-minute walk coincides with decline in a shorter 20-m walk among older adults. Objective The aim of this study was to describe patterns of change in the 20-m walk and 2-minute walk over 8 years among a large cohort of older adults. Should change be similar between tests of walking ability, separate retesting of prolonged walking may need to be reconsidered. Design A longitudinal, observational cohort study was conducted. Methods Data were from 1,893 older adults who were well-functioning (≥70 years of age). The 20-m walk and 2-minute walk were repeatedly measured over 8 years to measure change during short and prolonged periods of walking, respectively. Change was examined using a dual group-based trajectory model (dual model), and agreement between walking trajectories was quantified with a weighted kappa statistic. Results Three trajectory groups for the 20-m walk and 2-minute walk were identified. More than 86% of the participants were in similar trajectory groups for both tests from the dual model. There was high chance-corrected agreement (kappa=.84; 95% confidence interval=.82, .86) between the 20-m walk and 2-minute walk trajectory groups. Limitations One-third of the original Health, Aging and Body Composition (Health ABC) study cohort was excluded from analysis due to missing clinic visits, followed by being excluded for health reasons for performing the 2-minute walk, limiting generalizability to healthy older adults. Conclusions Patterns of change in the 2-minute walk are similar to those in the 20-m walk. Thus, separate retesting of the 2-minute walk may need to be reconsidered to gauge change in prolonged walking. PMID:24786943

Cognitive-Motor Interference during Walking in Older Adults with Probable Mild Cognitive Impairment

PubMed Central

Klotzbier, Thomas J.; Schott, Nadja

2017-01-01

Although several studies have shown that dual-tasking (DT) mobility is impaired in Alzheimer's disease, studies on the effects of DT conditions in probable Mild Cognitive Impairment (pMCI) have not yielded unequivocal results. The objectives of the study were to (1) examine the effect of a concurrent task on a complex walking task in adults with cognitive impairment; and (2) determine whether the effect varied with different difficulty levels of the concurrent task. Furthermore, the study was designed to evaluate the Trail-Walking Test (TWT) as a potential detection tool for MCI. We examined DT performance in 42 young adults (mean age 23.9 ± 1.98), and 43 older adults (mean age 68.2 ± 6.42). The MoCA was used to stratify the subjects into those with and without pMCI. DT was assessed using the TWT: participants completed 5 trials each of walking along a fixed pathway, stepping on targets with increasing sequential numbers (i.e., 1-2-…-15), and increasing sequential numbers and letters (i.e., 1-A-2-B-3-…-8). Motor and cognitive DT effects (DTE) were calculated for each task. ROC curves were used to distinguish younger and healthy older adults from older adults with pMCI. The TWT showed excellent test-retest reliability across all conditions and groups (ICC : 0.83–0.97). SEM% was also low (<11%) as was the MDC95% (<30%). Within the DT conditions, the pMCI group showed significantly longer durations for all tasks regardless of the cognitive load compared to the younger and the healthy older adults. The motor DTEs were greatest for the complex condition in older adults with pMCI more so than in comparison with younger and healthy older adults. ROC analyses confirmed that only the tasks with higher cognitive load could differentiate older adults with pMCI from controls (area under the curve >0.7, p < 0.05). The TWT is a reliable DT mobility measure in people with pMCI. However, the condition with high cognitive load is more sensitive than the condition with low cognitive load in identifying pMCI. The TWT-3 thus could serve as a screening tool for early detection of individuals with pMCI. Future studies need to determine the neural correlates for cognitive-motor interference in older adults with pMCI. PMID:29321738

Cognitive-Motor Interference during Walking in Older Adults with Probable Mild Cognitive Impairment.

PubMed

Klotzbier, Thomas J; Schott, Nadja

2017-01-01

Although several studies have shown that dual-tasking (DT) mobility is impaired in Alzheimer's disease, studies on the effects of DT conditions in probable Mild Cognitive Impairment (pMCI) have not yielded unequivocal results. The objectives of the study were to (1) examine the effect of a concurrent task on a complex walking task in adults with cognitive impairment; and (2) determine whether the effect varied with different difficulty levels of the concurrent task. Furthermore, the study was designed to evaluate the Trail-Walking Test (TWT) as a potential detection tool for MCI. We examined DT performance in 42 young adults (mean age 23.9 ± 1.98), and 43 older adults (mean age 68.2 ± 6.42). The MoCA was used to stratify the subjects into those with and without pMCI. DT was assessed using the TWT: participants completed 5 trials each of walking along a fixed pathway, stepping on targets with increasing sequential numbers (i.e., 1-2-…-15), and increasing sequential numbers and letters (i.e., 1-A-2-B-3-…-8). Motor and cognitive DT effects (DTE) were calculated for each task. ROC curves were used to distinguish younger and healthy older adults from older adults with pMCI. The TWT showed excellent test-retest reliability across all conditions and groups (ICC : 0.83-0.97). SEM% was also low (<11%) as was the MDC95% (<30%). Within the DT conditions, the pMCI group showed significantly longer durations for all tasks regardless of the cognitive load compared to the younger and the healthy older adults. The motor DTEs were greatest for the complex condition in older adults with pMCI more so than in comparison with younger and healthy older adults. ROC analyses confirmed that only the tasks with higher cognitive load could differentiate older adults with pMCI from controls (area under the curve >0.7, p < 0.05). The TWT is a reliable DT mobility measure in people with pMCI. However, the condition with high cognitive load is more sensitive than the condition with low cognitive load in identifying pMCI. The TWT-3 thus could serve as a screening tool for early detection of individuals with pMCI. Future studies need to determine the neural correlates for cognitive-motor interference in older adults with pMCI.

The reliability of the quantitative timed up and go test (QTUG) measured over five consecutive days under single and dual-task conditions in community dwelling older adults.

PubMed

Smith, Erin; Walsh, Lorcan; Doyle, Julie; Greene, Barry; Blake, Catherine

2016-01-01

The timed up and go (TUG) test is a commonly used assessment in older people with variations including the addition of a motor or cognitive dual-task, however in high functioning older adults it is more difficult to assess change. The quantified TUG (QTUG) uses inertial sensors to detect test and gait parameters during the test. If it is to be used in the longitudinal assessment of older adults, it is important that we know which parameters are reliable and under which conditions. This study aims to examine the relative reliability of the QTUG over five consecutive days under single, motor and cognitive dual-task conditions. Twelve community dwelling older adults (10 females, mean age 74.17 (3.88)) performed the QTUG under three conditions for five consecutive days. The relative reliability of each of the gait parameters was assessed using intra-class correlation coefficient (ICC 3,1) and standard error of measurement (SEM). Five of the measures demonstrated excellent reliability (ICC>0.70) under all three conditions (time to complete test, walk time, number of gait cycles, number of steps and return from turn time). Measures of variability and turn derived parameters demonstrated weak reliability under all three conditions (ICC=0.05-0.49). For the most reliable parameters under single-task conditions, the addition of a cognitive task resulted in a reduction in reliability suggesting caution when interpreting results under these conditions. Certain sensor derived parameters during the QTUG test may provide an additional resource in the longitudinal assessment of older people and earlier identification of falls risk. Copyright © 2015 Elsevier B.V. All rights reserved.

Walking delays anticipatory postural adjustments but not reaction times in a choice reaction task.

PubMed

Haridas, C; Gordon, I T; Misiaszek, J E

2005-06-01

During standing, anticipatory postural adjustments (APAs) and focal movements are delayed while performing a choice reaction task, compared with a simple reaction task. We hypothesized that APAs and focal movements of a choice reaction task would be similarly delayed during walking. Furthermore, reaction times are delayed during walking compared with standing. We further hypothesized that APAs and focal movements would be delayed during walking, compared with standing, for both simple and choice reaction tasks. Subjects either walked or stood on a treadmill while holding on to stable handles. They were asked to push or pull on the handles in response to a visual cue. Muscle activity was recorded from muscles of the leg (APA) and arm (RT). Our results were in agreement with previous work showing APA onset was delayed in the choice reaction task compared with the simple reaction task. In addition, the interval between the onset of APA and focal movement activity increased with choice reaction tasks. The task of walking did not delay the onset of focal movement for either the simple or choice reaction tasks. Walking did delay the onset of the APA, but only during choice reaction tasks. The results suggest the added demand of walking does not significantly modify the control of focal arm movements. However, additional attentional demands while walking may compromise anticipatory postural control.

The Effects of Aging and Dual Tasking on Human Gait Complexity During Treadmill Walking: A Comparative Study Using Quantized Dynamical Entropy and Sample Entropy.

PubMed

Ahmadi, Samira; Wu, Christine; Sepehri, Nariman; Kantikar, Anuprita; Nankar, Mayur; Szturm, Tony

2018-01-01

Quantized dynamical entropy (QDE) has recently been proposed as a new measure to quantify the complexity of dynamical systems with the purpose of offering a better computational efficiency. This paper further investigates the viability of this method using five different human gait signals. These signals are recorded while normal walking and while performing secondary tasks among two age groups (young and older age groups). The results are compared with the outcomes of previously established sample entropy (SampEn) measure for the same signals. We also study how analyzing segmented and spatially and temporally normalized signal differs from analyzing whole data. Our findings show that human gait signals become more complex as people age and while they are cognitively loaded. Center of pressure (COP) displacement in mediolateral direction is the best signal for showing the gait changes. Moreover, the results suggest that by segmenting data, more information about intrastride dynamical features are obtained. Most importantly, QDE is shown to be a reliable measure for human gait complexity analysis.

The dual task-cost of standing balance affects quality of life in mildly disabled MS people.

PubMed

Castelli, Letizia; De Luca, Francesca; Marchetti, Maria Rita; Sellitto, Giovanni; Fanelli, Fulvia; Prosperini, Luca

2016-05-01

The aim of this study was to explore the correlations between the dual-task cost (DTC) of standing balance and quality of life (QoL) in mildly disabled patients with multiple sclerosis (MS). In this cross-sectional study, patients affected by MS with an expanded disability status scale (EDSS) score of 3.0 or less and without an overt balance impairment were tested by means of static posturography under eyes-opened (single-task condition) and while performing the Stroop word-color test (dual-task condition), to estimate the DTC of standing balance. The self-reported 54-item MS quality of life questionnaire (MSQoL-54) was also administered to obtain a MS-specific assessment of health-related QoL. Among the 120 screened patients, 75 (53 women, 22 men) were tested. Although there was no impact of the DTC of standing balance on the physical and mental composite scores of MSQoL-54, patients who had a greater DTC of standing balance scored worse on role limitations due to physical problems (p = 0.007) and social function (p < 0.001), irrespective of demographic and other clinical characteristics including walking performance and cognitive status. However, the EDSS step and fatigue also contributed to reduced scores in these two QoL domains (p-values < 0.01). In conclusion, the phenomenon of cognitive-motor interference, investigated as DTC of standing balance, may affect specific QoL domains even in mildly disabled patients with MS and in the absence of an overt balance dysfunction.

Effect of uphill and downhill walking on walking performance in geriatric patients using a wheeled walker.

PubMed

Lindemann, Ulrich; Schwenk, Michael; Schmitt, Syn; Weyrich, Michael; Schlicht, Wolfgang; Becker, Clemens

2017-08-01

Wheeled walkers are recommended to improve walking performance in older persons and to encourage and assist participation in daily life. Nevertheless, using a wheeled walker can cause serious problems in the natural environment. This study aimed to compare uphill and downhill walking with walking level in geriatric patients using a wheeled walker. Furthermore, we investigated the effect of using a wheeled walker with respect to dual tasking when walking level. A total of 20 geriatric patients (median age 84.5 years) walked 10 m at their habitual pace along a level surface, uphill and downhill, with and without a standard wheeled walker. Gait speed, stride length and cadence were assessed by wearable sensors and the walk ratio was calculated. When using a wheeled walker while walking level the walk ratio improved (0.58 m/[steps/min] versus 0.57 m/[steps/min], p = 0.023) but gait speed decreased (1.07 m/s versus 1.12 m/s, p = 0.020) when compared to not using a wheeled walker. With respect to the walk ratio, uphill and downhill walking with a wheeled walker decreased walking performance when compared to level walking (0.54 m/[steps/min] versus 0.58 m/[steps/min], p = 0.023 and 0.55 m/[steps/min] versus 0.58 m/[steps/min], p = 0.001, respectively). At the same time, gait speed decreased (0.079 m/s versus 1.07 m/s, p < 0.0001) or was unaffected. The use of a wheeled walker improved the quality of level walking but the performance of uphill and downhill walking was worse compared to walking level when using a wheeled walker.

Perception of Self-Motion and Regulation of Walking Speed in Young-Old Adults.

PubMed

Lalonde-Parsi, Marie-Jasmine; Lamontagne, Anouk

2015-07-01

Whether a reduced perception of self-motion contributes to poor walking speed adaptations in older adults is unknown. In this study, speed discrimination thresholds (perceptual task) and walking speed adaptations (walking task) were compared between young (19-27 years) and young-old individuals (63-74 years), and the relationship between the performance on the two tasks was examined. Participants were evaluated while viewing a virtual corridor in a helmet-mounted display. Speed discrimination thresholds were determined using a staircase procedure. Walking speed modulation was assessed on a self-paced treadmill while exposed to different self-motion speeds ranging from 0.25 to 2 times the participants' comfortable speed. For each speed, participants were instructed to match the self-motion speed described by the moving corridor. On the walking task, participants displayed smaller walking speed errors at comfortable walking speeds compared with slower of faster speeds. The young-old adults presented larger speed discrimination thresholds (perceptual experiment) and larger walking speed errors (walking experiment) compared with young adults. Larger walking speed errors were associated with higher discrimination thresholds. The enhanced performance on the walking task at comfortable speed suggests that intersensory calibration processes are influenced by experience, hence optimized for frequently encountered conditions. The altered performance of the young-old adults on the perceptual and walking tasks, as well as the relationship observed between the two tasks, suggest that a poor perception of visual motion information may contribute to the poor walking speed adaptations that arise with aging.

The effect of military motion-assisted memory desensitization and reprocessing treatment on the symptoms of combat-related post traumatic stress disorder: first preliminary results.

PubMed

Vermetten, Eric; Meijer, Lydia; van der Wurff, Peter; Mert, Agali

2013-01-01

Although the symptoms of Post-Traumatic Stress Disorder (PTSD) in the general and military population seem very similar, combat-related PTSD (cr-PTSD) is typically thought to be more severe due to the repeated and prolonged exposure of traumatic events. Therapeutic adherence is reported a problem in military populations compromising treatment efficacy. Therefore, a new potential supplementary treatment is specially designed for patients with cr-PTSD. This intervention is called Military Motion Memory Desensitization and Reprocessing (3MDR). The treatment incorporates key elements of successful treatments as Virtual Reality Exposure (VRE) and Eye Movement Desensitization Reprocessing (EMDR) and adds motion to the condition. We aimed at designing a treatment procedure that preserved dual task processing principle, yet introduced new engagement by performing the desensitization during motion by to walking on a treadmill. Moreover, we aimed at exposure to real high-affect pictures of deployment setting. Subjects walk a repetitive cycle while walking and viewing high affect pictures of deployment scenes. Dual task processing was maintained by an oscillating ball. Aspects of presence are adhered to, to maximize possible positive outcome. Two veterans with chronic PTSD, received four weekly sessions of 3MDR therapy. The indicator of effectiveness was difference in CAPS (Clinical Administrated PTSD Scale)-score. The treatment was designed on the Computer Assisted Rehabilitation Environment (CAREN) facility. The 3MDR treatment did further decrease PTSD symptoms. Patients were highly satisfied about the treatment and had no attention to drop out. The results of the two cases suggest that the 3MDR treatment is a successful, more additional treatment that goes further into the patients affect where other treatment may stagnate. The presence was highly appreciated. Further research with more patients needs to be performed to obtain more reliable results.

Early presentation of gait impairment in Wolfram Syndrome

PubMed Central

2012-01-01

Background Classically characterized by early onset insulin-dependent diabetes mellitus, optic atrophy, deafness, diabetes insipidus, and neurological abnormalities, Wolfram syndrome (WFS) is also associated with atypical brainstem and cerebellar findings in the first decade of life. As such, we hypothesized that gait differences between individuals with WFS and typically developing (TD) individuals may be detectable across the course of the disease. Methods Gait was assessed for 13 individuals with WFS (min 6.4 yrs, max 25.8 yrs) and 29 age-matched, typically developing individuals (min 5.6 yrs, max 28.5 yrs) using a GAITRite ® walkway system. Velocity, cadence, step length, base of support and double support time were compared between groups. Results Across all tasks, individuals with WFS walked slower (p = 0.03), took shorter (p ≤ 0.001) and wider (p ≤ 0.001) steps and spent a greater proportion of the gait cycle in double support (p = 0.03) compared to TD individuals. Cadence did not differ between groups (p = 0.62). Across all tasks, age was significantly correlated with cadence and double support time in the TD group but only double support time was correlated with age in the WFS group and only during preferred pace forward (rs= 0.564, p = 0.045) and dual task forward walking (rs= 0.720, p = 0.006) tasks. Individuals with WFS also had a greater number of missteps during tandem walking (p ≤ 0.001). Within the WFS group, spatiotemporal measures of gait did not correlate with measures of visual acuity. Balance measures negatively correlated with normalized gait velocity during fast forward walking (rs = −0.59, p = 0.03) and percent of gait cycle in double support during backward walking (rs = −0.64, p = 0.03). Conclusions Quantifiable gait impairments can be detected in individuals with WFS earlier than previous clinical observations suggested. These impairments are not fully accounted for by the visual or balance deficits associated with WFS, and may be a reflection of early cerebellar and/or brainstem abnormalities. Effective patient-centered treatment paradigms could benefit from a more complete understanding of the progression of motor and other neurological symptom presentation in individuals with WFS. PMID:23217193

Multimodal exercise intervention improves frontal cognitive functions and gait in Alzheimer's disease: a controlled trial.

PubMed

Coelho, Flávia Gomes de Melo; Andrade, Larissa Pires; Pedroso, Renata Valle; Santos-Galduroz, Ruth Ferreira; Gobbi, Sebastião; Costa, José Luiz Riani; Gobbi, Lilian Teresa Bucken

2013-01-01

The objective of the present study was to investigate the effect of a multimodal exercise intervention on frontal cognitive functions and kinematic gait parameters in patients with Alzheimer's disease. A sample of elderly patients with Alzheimer's disease (n=27) were assigned to a training group (n=14; aged 78.0±7.3 years) and a control group (n=13; aged 77.1±7.4 years). Multimodal exercise intervention includes motor activities and cognitive tasks simultaneously. The participants attended a 1-h session three times a week for 16 weeks, and the control participants maintained their regular daily activities during the same period. The frontal cognitive functions were evaluated using the Frontal Assessment Battery, the Clock Drawing Test and the Symbol Search Subtest. The kinematic parameters of gait-cadence, stride length and stride speed were analyzed under two conditions: (i) free gait (single task); and (ii) gait with frontal cognitive task (walking and counting down from 20--dual task). The patients in the intervention group significantly increased the scores in frontal cognitive variables, Frontal Assessment Battery (P<0.001) and Symbol Search Subtest (P<0.001) after the 16-week period. The control group decreased the scores in the Clock Drawing Test (P=0.001) and increased the number of counting errors during the dual task (P=0.008) after the same period. The multimodal exercise intervention improved the frontal cognitive functions in patients with Alzheimer's disease. © 2012 Japan Geriatrics Society.

Effect of music-based multitask training on gait, balance, and fall risk in elderly people: a randomized controlled trial.

PubMed

Trombetti, Andrea; Hars, Mélany; Herrmann, François R; Kressig, Reto W; Ferrari, Serge; Rizzoli, René

2011-03-28

Falls occur mainly while walking or performing concurrent tasks. We determined whether a music-based multitask exercise program improves gait and balance and reduces fall risk in elderly individuals. We conducted a 12-month randomized controlled trial involving 134 community-dwelling individuals older than 65 years, who are at increased risk of falling. They were randomly assigned to an intervention group (n = 66) or a delayed intervention control group scheduled to start the program 6 months later (n = 68). The intervention was a 6-month multitask exercise program performed to the rhythm of piano music. Change in gait variability under dual-task condition from baseline to 6 months was the primary end point. Secondary outcomes included changes in balance, functional performances, and fall risk. At 6 months, there was a reduction in stride length variability (adjusted mean difference, -1.4%; P < .002) under dual-task condition in the intervention group, compared with the delayed intervention control group. Balance and functional tests improved compared with the control group. There were fewer falls in the intervention group (incidence rate ratio, 0.46; 95% confidence interval, 0.27-0.79) and a lower risk of falling (relative risk, 0.61; 95% confidence interval, 0.39-0.96). Similar changes occurred in the delayed intervention control group during the second 6-month period with intervention. The benefit of the intervention on gait variability persisted 6 months later. In community-dwelling older people at increased risk of falling, a 6-month music-based multitask exercise program improved gait under dual-task condition, improved balance, and reduced both the rate of falls and the risk of falling. Trial Registration clinicaltrials.gov Identifier: NCT01107288.

Concurrent validity of the Microsoft Kinect for Windows v2 for measuring spatiotemporal gait parameters.

PubMed

Dolatabadi, Elham; Taati, Babak; Mihailidis, Alex

2016-09-01

This paper presents a study to evaluate the concurrent validity of the Microsoft Kinect for Windows v2 for measuring the spatiotemporal parameters of gait. Twenty healthy adults performed several sequences of walks across a GAITRite mat under three different conditions: usual pace, fast pace, and dual task. Each walking sequence was simultaneously captured with two Kinect for Windows v2 and the GAITRite system. An automated algorithm was employed to extract various spatiotemporal features including stance time, step length, step time and gait velocity from the recorded Kinect v2 sequences. Accuracy in terms of reliability, concurrent validity and limits of agreement was examined for each gait feature under different walking conditions. The 95% Bland-Altman limits of agreement were narrow enough for the Kinect v2 to be a valid tool for measuring all reported spatiotemporal parameters of gait in all three conditions. An excellent intraclass correlation coefficient (ICC2, 1) ranging from 0.9 to 0.98 was observed for all gait measures across different walking conditions. The inter trial reliability of all gait parameters were shown to be strong for all walking types (ICC3, 1 > 0.73). The results of this study suggest that the Kinect for Windows v2 has the capacity to measure selected spatiotemporal gait parameters for healthy adults. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Adaptations of Prefrontal Brain Activity, Executive Functions, and Gait in Healthy Elderly Following Exergame and Balance Training: A Randomized-Controlled Study

PubMed Central

Schättin, Alexandra; Arner, Rendel; Gennaro, Federico; de Bruin, Eling D.

2016-01-01

During aging, the prefrontal cortex (PFC) undergoes age-dependent neuronal changes influencing cognitive and motor functions. Motor-learning interventions are hypothesized to ameliorate motor and cognitive deficits in older adults. Especially, video game-based physical exercise might have the potential to train motor in combination with cognitive abilities in older adults. The aim of this study was to compare conventional balance training with video game-based physical exercise, a so-called exergame, on the relative power (RP) of electroencephalographic (EEG) frequencies over the PFC, executive function (EF), and gait performance. Twenty-seven participants (mean age 79.2 ± 7.3 years) were randomly assigned to one of two groups. All participants completed 24 trainings including three times a 30 min session/week. The EEG measurements showed that theta RP significantly decreased in favor of the exergame group [L(14) = 6.23, p = 0.007]. Comparing pre- vs. post-test, EFs improved both within the exergame (working memory: z = −2.28, p = 0.021; divided attention auditory: z = −2.51, p = 0.009; divided attention visual: z = −2.06, p = 0.040; go/no-go: z = −2.55, p = 0.008; set-shifting: z = −2.90, p = 0.002) and within the balance group (set-shifting: z = −2.04, p = 0.042). Moreover, spatio-temporal gait parameters primarily improved within the exergame group under dual-task conditions (speed normal walking: z = −2.90, p = 0.002; speed fast walking: z = −2.97, p = 0.001; cadence normal walking: z = −2.97, p = 0.001; stride length fast walking: z = −2.69, p = 0.005) and within the balance group under single-task conditions (speed normal walking: z = −2.54, p = 0.009; speed fast walking: z = −1.98, p = 0.049; cadence normal walking: z = −2.79, p = 0.003). These results indicate that exergame training as well as balance training positively influence prefrontal cortex activity and/or function in varying proportion. PMID:27932975

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke.

PubMed

Clark, David J; Chatterjee, Sudeshna A; McGuirk, Theresa E; Porges, Eric C; Fox, Emily J; Balasubramanian, Chitralakshmi K

2018-02-01

Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist scoring of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities-specific Balance Confidence Scale, respectively. There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. Published by Elsevier B.V.

Sympathetic nervous system activity measured by skin conductance quantifies the challenge of walking adaptability tasks after stroke

PubMed Central

Clark, David J.; Chatterjee, Sudeshna A.; McGuirk, Theresa E.; Porges, Eric C.; Fox, Emily J.; Balasubramanian, Chitralakshmi K.

2018-01-01

Background Walking adaptability tasks are challenging for people with motor impairments. The construct of perceived challenge is typically measured by self-report assessments, which are susceptible to subjective measurement error. The development of an objective physiologically-based measure of challenge may help to improve the ability to assess this important aspect of mobility function. The objective of this study to investigate the use of sympathetic nervous system (SNS) activity measured by skin conductance to gauge the physiological stress response to challenging walking adaptability tasks in people post-stroke. Methods Thirty adults with chronic post-stroke hemiparesis performed a battery of seventeen walking adaptability tasks. SNS activity was measured by skin conductance from the palmar surface of each hand. The primary outcome variable was the percent change in skin conductance level (ΔSCL) between the baseline resting and walking phases of each task. Task difficulty was measured by performance speed and by physical therapist grading of performance. Walking function and balance confidence were measured by preferred walking speed and the Activities Specific Balance Confidence Scale, respectively. Results There was a statistically significant negative association between ΔSCL and task performance speed and between ΔSCL and clinical score, indicating that tasks with greater SNS activity had slower performance speed and poorer clinical scores. ΔSCL was significantly greater for low functioning participants versus high functioning participants, particularly during the most challenging walking adaptability tasks. Conclusion This study supports the use of SNS activity measured by skin conductance as a valuable approach for objectively quantifying the perceived challenge of walking adaptability tasks in people post-stroke. PMID:29216598

Walking-adaptability assessments with the Interactive Walkway: Between-systems agreement and sensitivity to task and subject variations.

PubMed

Geerse, Daphne J; Coolen, Bert H; Roerdink, Melvyn

2017-05-01

The ability to adapt walking to environmental circumstances is an important aspect of walking, yet difficult to assess. The Interactive Walkway was developed to assess walking adaptability by augmenting a multi-Kinect-v2 10-m walkway with gait-dependent visual context (stepping targets, obstacles) using real-time processed markerless full-body kinematics. In this study we determined Interactive Walkway's usability for walking-adaptability assessments in terms of between-systems agreement and sensitivity to task and subject variations. Under varying task constraints, 21 healthy subjects performed obstacle-avoidance, sudden-stops-and-starts and goal-directed-stepping tasks. Various continuous walking-adaptability outcome measures were concurrently determined with the Interactive Walkway and a gold-standard motion-registration system: available response time, obstacle-avoidance and sudden-stop margins, step length, stepping accuracy and walking speed. The same holds for dichotomous classifications of success and failure for obstacle-avoidance and sudden-stops tasks and performed short-stride versus long-stride obstacle-avoidance strategies. Continuous walking-adaptability outcome measures generally agreed well between systems (high intraclass correlation coefficients for absolute agreement, low biases and narrow limits of agreement) and were highly sensitive to task and subject variations. Success and failure ratings varied with available response times and obstacle types and agreed between systems for 85-96% of the trials while obstacle-avoidance strategies were always classified correctly. We conclude that Interactive Walkway walking-adaptability outcome measures are reliable and sensitive to task and subject variations, even in high-functioning subjects. We therefore deem Interactive Walkway walking-adaptability assessments usable for obtaining an objective and more task-specific examination of one's ability to walk, which may be feasible for both high-functioning and fragile populations since walking adaptability can be assessed at various levels of difficulty. Copyright © 2017 Elsevier B.V. All rights reserved.

The effects of smartphone multitasking on gait and dynamic balance.

PubMed

Lee, Jeon Hyeong; Lee, Myoung Hee

2018-02-01

[Purpose] This study was performed to analyze the influence of smartphone multitasking on gait and dynamic balance. [Subjects and Methods] The subjects were 19 male and 20 female university students. There were 4 types of gait tasks: General Gait (walking without a task), Task Gait 1 (walking while writing a message), Task Gait 2 (walking while writing a message and listening to music), Task Gait 3 (walking while writing a message and having a conversation). To exclude the learning effect, the order of tasks was randomized. The Zebris FDM-T treadmill system (Zebris Medical GmbH, Germany) was used to measure left and right step length and width, and a 10 m walking test (10MWT) was conducted for gait velocity. In addition, a Timed Up and Go test (TUG) was used to measure dynamic balance. All the tasks were performed 3 times, and the mean of the measured values was analyzed. [Results] There were no statistically significant differences in step length and width. There were statistically significant differences in the 10MWT and TUG tests. [Conclusion] Using a smartphone while walking decreases a person's dynamic balance and walking ability. It is considered that accident rates are higher when using a smartphone.

An innovative training program based on virtual reality and treadmill: effects on gait of persons with multiple sclerosis.

PubMed

Peruzzi, Agnese; Zarbo, Ignazio Roberto; Cereatti, Andrea; Della Croce, Ugo; Mirelman, Anat

2017-07-01

In this single blind randomized controlled trial, we examined the effect of a virtual reality-based training on gait of people with multiple sclerosis. Twenty-five individuals with multiple sclerosis with mild to moderate disability were randomly assigned to either the control group (n = 11) or the experimental group (n = 14). The subjects in the control group received treadmill training. Subjects in the experimental group received virtual reality based treadmill training. Clinical measures and gait parameters were evaluated. Subjects in both the groups significantly improved the walking endurance and speed, cadence and stride length, lower limb joint ranges of motion and powers, during single and dual task gait. Moreover, subjects in the experimental group also improved balance, as indicated by the results of the clinical motor tests (p < 0.05). Between-group comparisons revealed that the experimental group improved significantly more than control group in hip range of motion and hip generated power at terminal stance at post-training. Our results support the perceived benefits of training programs that incorporate virtual reality to improve gait measures in individuals with multiple sclerosis. Implication of rehabilitation Gait deficits are common in multiple sclerosis (85%) and worsen during dual task activities. Intensive and progressive treadmill training, with and without virtual reality, is effective on dual task gait in persons with multiple sclerosis. Virtual reality-based treadmill training requiring obstacle negotiation increases the range of motion and the power generated at the hip, consequently allowing longer stride length and, consequently, higher gait speed.

Brain activations during bimodal dual tasks depend on the nature and combination of component tasks

PubMed Central

Salo, Emma; Rinne, Teemu; Salonen, Oili; Alho, Kimmo

2015-01-01

We used functional magnetic resonance imaging to investigate brain activations during nine different dual tasks in which the participants were required to simultaneously attend to concurrent streams of spoken syllables and written letters. They performed a phonological, spatial or “simple” (speaker-gender or font-shade) discrimination task within each modality. We expected to find activations associated specifically with dual tasking especially in the frontal and parietal cortices. However, no brain areas showed systematic dual task enhancements common for all dual tasks. Further analysis revealed that dual tasks including component tasks that were according to Baddeley's model “modality atypical,” that is, the auditory spatial task or the visual phonological task, were not associated with enhanced frontal activity. In contrast, for other dual tasks, activity specifically associated with dual tasking was found in the left or bilateral frontal cortices. Enhanced activation in parietal areas, however, appeared not to be specifically associated with dual tasking per se, but rather with intermodal attention switching. We also expected effects of dual tasking in left frontal supramodal phonological processing areas when both component tasks required phonological processing and in right parietal supramodal spatial processing areas when both tasks required spatial processing. However, no such effects were found during these dual tasks compared with their component tasks performed separately. Taken together, the current results indicate that activations during dual tasks depend in a complex manner on specific demands of component tasks. PMID:25767443

Relationship between oxygen cost of walking and level of walking disability after stroke: An experimental study.

PubMed

Polese, Janaine C; Ada, Louise; Teixeira-Salmela, Luci F

2018-01-01

Since physical inactivity is the major risk factor for recurrent stroke, it is important to understand how level of disability impacts oxygen uptake by people after stroke. This study investigated the nature of the relationship between level of disability and oxygen cost in people with chronic stroke. Level of walking disability was measured as comfortable walking speed using the 10-m Walk Test reported in m/s with 55 ambulatory people 2 years after stroke. Oxygen cost was measured during 3 walking tasks: overground walking at comfortable speed, overground walking at fast speed, and stair walking at comfortable speed. Oxygen cost was calculated from oxygen uptake divided by distance covered during walking and reported in ml∙kg -1 ∙m -1 . The relationship between level of walking disability and oxygen cost was curvilinear for all 3 walking tasks. One quadratic model accounted for 81% (95% CI [74, 88]) of the variance in oxygen cost during the 3 walking tasks: [Formula: see text] DISCUSSION: The oxygen cost of walking was related the level of walking disability in people with chronic stroke, such that the more disabled the individual, the higher the oxygen cost of walking; with oxygen cost rising sharply as disability became severe. An equation that relates oxygen cost during different walking tasks according to the level of walking disability allows clinicians to determine oxygen cost indirectly without the difficulty of measuring oxygen uptake directly. Copyright © 2017 John Wiley & Sons, Ltd.

Effect of arousal on internal clock speed in real action and mental imagery.

PubMed

Ozel, Sylvie; Larue, Jacques; Dosseville, Fabrice

2004-09-01

The possible implication of an internal clock as a mechanism accounting for the temporal homology between actual and mental walking is studied. To observe this phenomenon, stressful sound stimuli were used to increase arousal, which is known to activate the internal clock. Seventeen participants performed three tasks: (1) a time production task, used as a reference task reflecting the internal clock speed; (2) an actual walking task; and (3) a mental walking task, all three in two sound conditions (no noise and noise). The results showed a significant effect of arousal on time in each task. The effect of noise, increasing the arousal level, was greater in time production and mental imagery tasks than in real action. In addition, the percentages of change between the two sound conditions for actual and mental walking time were not statistically different. These findings are further evidence of the existence of a timing process common to actual and mental walking. The data are consistent with the implication of an internal clock in both actual and mental walking.

Executive Control Deficits as a Prodrome to Falls in Healthy Older Adults: A Prospective Study Linking Thinking, Walking, and Falling

PubMed Central

Herman, Talia; Mirelman, Anat; Giladi, Nir; Schweiger, Avraham

2010-01-01

Background. Executive function (EF) deficits may increase fall risk, even among older adults with no overt cognitive impairment. Indeed, the effects of dual tasking (DT) on gait, a challenge to executive control, are more exaggerated in persons with a history of falls. Prospective evidence is, however, lacking. Methods. We prospectively evaluated whether EF predicts falls over a 2-year period among 262 community-living, healthy, and well-functioning older adults, focusing on the 201 who reported no falls during the previous year. At baseline, participants completed a computerized cognitive battery that generated an index of EF and other cognitive domains. Gait was assessed using performance-based tests and by quantifying walking during single- and dual-task conditions. Results. The 262 participants (mean age: 76.3 ± 4.3 years, 60.3% women) had intact cognitive function on testing, a low comorbidity index, and good mobility. The EF index predicted future falls. Among those who reported no previous falls, participants in the worst EF quartile were three times more likely to fall during the 2 years of follow-up, and they were more likely to transition from nonfaller to faller sooner. DT gait variability also predicted future falls and multiple falls, whereas other measures of cognitive function, gait, and mobility did not. Conclusions. Among healthy older adults, individuals with poorer EF are more prone to falls. Higher-level cognitive functions such as those regulated by the frontal lobes are apparently needed for safe everyday navigation that demands multitasking. Optimal screening, early detection, and treatment of falls should, apparently, also target this cognitive domain. PMID:20484336

Feasibility of a 6-month exercise and recreation program to improve executive functioning and memory of individuals with chronic stroke

PubMed Central

Rand, Debbie; Eng, Janice J.; Liu-Ambrose, Teresa; Tawashy, Amira E.

2011-01-01

Background Physical activity has been shown to be beneficial for improving cognitive function in healthy older adults. However there is limited research on the benefits of physical activity on cognitive performance after stroke. Objective To determine if a combined exercise and recreation program can improve the executive functioning and memory in individuals with chronic stroke. Methods 11 ambulatory subjects with chronic stroke (mean age 67±10.8 years) participated in a 6 month program of exercise for 2 hours and recreation for 1 hour weekly. Executive functions and memory were assessed at baseline, 3, and 6 months by a battery of standard neuropsychological tests including response inhibition, cognitive flexibility, dual task (motor plus cognitive) and memory. Motor ability was also assessed. Non-parametric statistics were used to assess the differences between the three assessments. Results At baseline, substantial deficits in all aspects of executive functioning were revealed. From baseline to 3 mo, the mean improvement was 10±14% (χ2=9.3, p=0.0025) for the dual task (Walking while Talking), −3±22% (χ2=2.4, p>0.05) for response inhibition (Stroop test) and 61±69% (χ2=8.0, p=0.04) for memory (Rey Auditory Verbal Learning Test - long delay). From baseline to 6 months, the mean improvement was 7±7.5% (χ2=12.0, p=0.007) for response inhibition (Stroop Test). In addition, knee strength and walking speed improved significantly at 3 months. Conclusions This pilot study suggests that exercise and recreation may improve memory and executive functions of community dwelling individuals with stroke. Further studies require a larger sample size and a control group. PMID:20460494

Unexpected Dual Task Benefits on Cycling in Parkinson Disease and Healthy Adults: A Neuro-Behavioral Model

PubMed Central

Altmann, Lori J. P.; Stegemöller, Elizabeth; Hazamy, Audrey A.; Wilson, Jonathan P.; Okun, Michael S.; McFarland, Nikolaus R.; Shukla, Aparna Wagle; Hass, Chris J.

2015-01-01

Background When performing two tasks at once, a dual task, performance on one or both tasks typically suffers. People with Parkinson’s disease (PD) usually experience larger dual task decrements on motor tasks than healthy older adults (HOA). Our objective was to investigate the decrements in cycling caused by performing cognitive tasks with a range of difficulty in people with PD and HOAs. Methods Twenty-eight participants with Parkinson’s disease and 20 healthy older adults completed a baseline cycling task with no secondary tasks and then completed dual task cycling while performing 12 tasks from six cognitive domains representing a wide range of difficulty. Results Cycling was faster during dual task conditions than at baseline, and was significantly faster for six tasks (all p<.02) across both groups. Cycling speed improved the most during the easiest cognitive tasks, and cognitive performance was largely unaffected. Cycling improvement was predicted by task difficulty (p<.001). People with Parkinson’s disease cycled slower (p<.03) and showed reduced dual task benefits (p<.01) than healthy older adults. Conclusions Unexpectedly, participants’ motor performance improved during cognitive dual tasks, which cannot be explained in current models of dual task performance. To account for these findings, we propose a model integrating dual task and acute exercise approaches which posits that cognitive arousal during dual tasks increases resources to facilitate motor and cognitive performance, which is subsequently modulated by motor and cognitive task difficulty. This model can explain both the improvement observed on dual tasks in the current study and more typical dual task findings in other studies. PMID:25970607

The effects of smartphone multitasking on gait and dynamic balance

PubMed Central

Lee, Jeon Hyeong; Lee, Myoung Hee

2018-01-01

[Purpose] This study was performed to analyze the influence of smartphone multitasking on gait and dynamic balance. [Subjects and Methods] The subjects were 19 male and 20 female university students. There were 4 types of gait tasks: General Gait (walking without a task), Task Gait 1 (walking while writing a message), Task Gait 2 (walking while writing a message and listening to music), Task Gait 3 (walking while writing a message and having a conversation). To exclude the learning effect, the order of tasks was randomized. The Zebris FDM-T treadmill system (Zebris Medical GmbH, Germany) was used to measure left and right step length and width, and a 10 m walking test (10MWT) was conducted for gait velocity. In addition, a Timed Up and Go test (TUG) was used to measure dynamic balance. All the tasks were performed 3 times, and the mean of the measured values was analyzed. [Results] There were no statistically significant differences in step length and width. There were statistically significant differences in the 10MWT and TUG tests. [Conclusion] Using a smartphone while walking decreases a person’s dynamic balance and walking ability. It is considered that accident rates are higher when using a smartphone. PMID:29545698

Testing the Limits of Optimizing Dual-Task Performance in Younger and Older Adults

PubMed Central

Strobach, Tilo; Frensch, Peter; Müller, Herrmann Josef; Schubert, Torsten

2012-01-01

Impaired dual-task performance in younger and older adults can be improved with practice. Optimal conditions even allow for a (near) elimination of this impairment in younger adults. However, it is unknown whether such (near) elimination is the limit of performance improvements in older adults. The present study tests this limit in older adults under conditions of (a) a high amount of dual-task training and (b) training with simplified component tasks in dual-task situations. The data showed that a high amount of dual-task training in older adults provided no evidence for an improvement of dual-task performance to the optimal dual-task performance level achieved by younger adults. However, training with simplified component tasks in dual-task situations exclusively in older adults provided a similar level of optimal dual-task performance in both age groups. Therefore through applying a testing the limits approach, we demonstrated that older adults improved dual-task performance to the same level as younger adults at the end of training under very specific conditions. PMID:22408613

Age-related decrements in dual-task performance: Comparison of different mobility and cognitive tasks. A cross sectional study.

PubMed

Brustio, Paolo Riccardo; Magistro, Daniele; Zecca, Massimiliano; Rabaglietti, Emanuela; Liubicich, Monica Emma

2017-01-01

This cross-sectional study investigated the age-related differences in dual-task performance both in mobility and cognitive tasks and the additive dual-task costs in a sample of older, middle-aged and young adults. 74 older adults (M = 72.63±5.57 years), 58 middle-aged adults (M = 46.69±4.68 years) and 63 young adults (M = 25.34±3.00 years) participated in the study. Participants performed different mobility and subtraction tasks under both single- and dual-task conditions. Linear regressions, repeated-measures and one-way analyses of covariance were used, The results showed: significant effects of the age on the dual and mobility tasks (p<0.05) and differences among the age-groups in the combined dual-task costs (p<0.05); significant decreases in mobility performance under dual-task conditions in all groups (p<0.05) and a decrease in cognitive performance in the older group (p<0.05). Dual-task activity affected mobility and cognitive performance, especially in older adults who showed a higher dual-task cost, suggesting that dual-tasks activities are affected by the age and consequently also mobility and cognitive tasks are negatively influenced.

Walking adaptability therapy after stroke: study protocol for a randomized controlled trial.

PubMed

Timmermans, Celine; Roerdink, Melvyn; van Ooijen, Marielle W; Meskers, Carel G; Janssen, Thomas W; Beek, Peter J

2016-08-26

Walking in everyday life requires the ability to adapt walking to the environment. This adaptability is often impaired after stroke, and this might contribute to the increased fall risk after stroke. To improve safe community ambulation, walking adaptability training might be beneficial after stroke. This study is designed to compare the effects of two interventions for improving walking speed and walking adaptability: treadmill-based C-Mill therapy (therapy with augmented reality) and the overground FALLS program (a conventional therapy program). We hypothesize that C-Mill therapy will result in better outcomes than the FALLS program, owing to its expected greater amount of walking practice. This is a single-center parallel group randomized controlled trial with pre-intervention, post-intervention, retention, and follow-up tests. Forty persons after stroke (≥3 months) with deficits in walking or balance will be included. Participants will be randomly allocated to either C-Mill therapy or the overground FALLS program for 5 weeks. Both interventions will incorporate practice of walking adaptability and will be matched in terms of frequency, duration, and therapist attention. Walking speed, as determined by the 10 Meter Walking Test, will be the primary outcome measure. Secondary outcome measures will pertain to walking adaptability (10 Meter Walking Test with context or cognitive dual-task and Interactive Walkway assessments). Furthermore, commonly used clinical measures to determine walking ability (Timed Up-and-Go test), walking independence (Functional Ambulation Category), balance (Berg Balance Scale), and balance confidence (Activities-specific Balance Confidence scale) will be used, as well as a complementary set of walking-related assessments. The amount of walking practice (the number of steps taken per session) will be registered using the treadmill's inbuilt step counter (C-Mill therapy) and video recordings (FALLS program). This process measure will be compared between the two interventions. This study will assess the effects of treadmill-based C-Mill therapy compared with the overground FALLS program and thereby the relative importance of the amount of walking practice as a key aspect of effective intervention programs directed at improving walking speed and walking adaptability after stroke. Netherlands Trial Register NTR4030 . Registered on 11 June 2013, amendment filed on 17 June 2016.

Transferability of Dual-Task Coordination Skills after Practice with Changing Component Tasks

PubMed Central

Schubert, Torsten; Liepelt, Roman; Kübler, Sebastian; Strobach, Tilo

2017-01-01

Recent research has demonstrated that dual-task performance with two simultaneously presented tasks can be substantially improved as a result of practice. Among other mechanisms, theories of dual-task practice-relate this improvement to the acquisition of task coordination skills. These skills are assumed (1) to result from dual-task practice, but not from single-task practice, and (2) to be independent from the specific stimulus and response mappings during the practice situation and, therefore, transferable to new dual task situations. The present study is the first that provides an elaborated test of these assumptions in a context with well-controllable practice and transfer situations. To this end, we compared the effects of dual-task and single-task practice with a visual and an auditory sensory-motor component task on the dual-task performance in a subsequent transfer session. Importantly, stimulus and stimulus-response mapping conditions in the two component tasks changed repeatedly during practice sessions, which prevents that automatized stimulus-response associations may be transferred from practice to transfer. Dual-task performance was found to be improved after practice with the dual tasks in contrast to the single-task practice. These findings are consistent with the assumption that coordination skills had been acquired, which can be transferred to other dual-task situations independently on the specific stimulus and response mapping conditions of the practiced component tasks. PMID:28659844

Reduced Cognitive-Motor Interference on Voluntary Balance Control in Older Tai Chi Practitioners.

PubMed

Varghese, Rini; Hui-Chan, Christina W Y; Bhatt, Tanvi

2016-01-01

Recent dual-task studies suggest that Tai Chi practitioners displayed better control of standing posture and maintained a quicker response time of postural muscle activation during a stepping down activity. Whether this effect extends to voluntary balance control, specifically the limits of excursion of the center of pressure, remains to be examined. The purpose of this study was to evaluate the cognitive-motor interference pattern by examining the effects of a concurrently performed cognitive task on attention of voluntary balance control in older adults who are long-term practitioners of Tai Chi. Ten older Tai Chi practitioners and 10 age-matched nonpractitioners performed a voluntary balance task that required them to shift their weight to reach a preset target in the forward and backward directions, with (single task, ST) and without (dual task, DT) a secondary cognitive task, which was the counting backward task. The counting backward task required the individual to compute and verbalize a series of arithmetic differences between a given pair of randomly generated numbers. The cognitive task was also performed independently (cognitive-ST). All trials were performed in a random order. Balance outcomes included reaction time, movement velocity, and maximal excursion of the center of pressure provided by the NeuroCom system. Cognitive outcome was the number of correct responses generated within the 8-second trial during the ST and DT conditions. Outcome variables were analyzed using a 2-factor, group by task, analysis of variance. DT costs for the variables were calculated as the relative difference between ST and DT conditions and were compared between the 2 groups using independent t tests. Tai Chi practitioners displayed shorter reaction times (P < .001) and faster movement velocities (P < .05) of their center of pressure than older nonpractitioners for both directions; however, no difference was found between the maximal excursions of the 2 groups. Cost analyses revealed that reaction time and cognitive costs were significantly lower in the Tai Chi practitioners for both forward and backward directions (P < .05); however, similar findings for movement velocity costs were significant only in the backward direction (P < .05). Our results suggest that Tai Chi practitioners expended fewer motor and cognitive resources than older nonpractitioners during a fairly complex (dynamic) postural equilibrium task while performing a verbal working memory task. They exhibited lesser cognitive-motor interference and thus better allocation of attentional resources toward the voluntary balance control task. Given that dynamic balance is a crucial prerequisite for walking and dual-tasking ability is considered to be a significant predictor of falls in older adults, our results might point at the possible long-term benefits of Tai Chi practice to counteract age-related decline in dual-tasking ability. Findings present preliminary data for further investigation, especially related to potential benefits in fall prevention.

Musical expertise has minimal impact on dual task performance.

PubMed

Cocchini, Gianna; Filardi, Maria Serena; Crhonkova, Marcela; Halpern, Andrea R

2017-05-01

Studies investigating effect of practice on dual task performance have yielded conflicting findings, thus supporting different theoretical accounts about the organisation of attentional resources when tasks are performed simultaneously. Because practice has been proven to reduce the demand of attention for the trained task, the impact of long-lasting training on one task is an ideal way to better understand the mechanisms underlying dual task decline in performance. Our study compared performance during dual task execution in expert musicians compared to controls with little if any musical experience. Participants performed a music recognition task and a visuo-spatial task separately (single task) or simultaneously (dual task). Both groups showed a significant but similar performance decline during dual tasks. In addition, the two groups showed a similar decline of dual task performance during encoding and retrieval of the musical information, mainly attributed to a decline in sensitivity. Our results suggest that attention during dual tasks is similarly distributed by expert and non-experts. These findings are in line with previous studies showing a lack of sensitivity to difficulty and lack of practice effect during dual tasks, supporting the idea that different tasks may rely on different and not-sharable attentional resources.

Effects of emotionally charged auditory stimulation on gait performance in the elderly: a preliminary study.

PubMed

Rizzo, John-Ross; Raghavan, Preeti; McCrery, J R; Oh-Park, Mooyeon; Verghese, Joe

2015-04-01

To evaluate the effect of a novel divided attention task-walking under auditory constraints-on gait performance in older adults and to determine whether this effect was moderated by cognitive status. Validation cohort. General community. Ambulatory older adults without dementia (N=104). Not applicable. In this pilot study, we evaluated walking under auditory constraints in 104 older adults who completed 3 pairs of walking trials on a gait mat under 1 of 3 randomly assigned conditions: 1 pair without auditory stimulation and 2 pairs with emotionally charged auditory stimulation with happy or sad sounds. The mean age of subjects was 80.6±4.9 years, and 63% (n=66) were women. The mean velocity during normal walking was 97.9±20.6cm/s, and the mean cadence was 105.1±9.9 steps/min. The effect of walking under auditory constraints on gait characteristics was analyzed using a 2-factorial analysis of variance with a 1-between factor (cognitively intact and minimal cognitive impairment groups) and a 1-within factor (type of auditory stimuli). In both happy and sad auditory stimulation trials, cognitively intact older adults (n=96) showed an average increase of 2.68cm/s in gait velocity (F1.86,191.71=3.99; P=.02) and an average increase of 2.41 steps/min in cadence (F1.75,180.42=10.12; P<.001) as compared with trials without auditory stimulation. In contrast, older adults with minimal cognitive impairment (Blessed test score, 5-10; n=8) showed an average reduction of 5.45cm/s in gait velocity (F1.87,190.83=5.62; P=.005) and an average reduction of 3.88 steps/min in cadence (F1.79,183.10=8.21; P=.001) under both auditory stimulation conditions. Neither baseline fall history nor performance of activities of daily living accounted for these differences. Our results provide preliminary evidence of the differentiating effect of emotionally charged auditory stimuli on gait performance in older individuals with minimal cognitive impairment compared with those without minimal cognitive impairment. A divided attention task using emotionally charged auditory stimuli might be able to elicit compensatory improvement in gait performance in cognitively intact older individuals, but lead to decompensation in those with minimal cognitive impairment. Further investigation is needed to compare gait performance under this task to gait on other dual-task paradigms and to separately examine the effect of physiological aging versus cognitive impairment on gait during walking under auditory constraints. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Age-related decrements in dual-task performance: Comparison of different mobility and cognitive tasks. A cross sectional study

PubMed Central

Brustio, Paolo Riccardo; Zecca, Massimiliano; Rabaglietti, Emanuela; Liubicich, Monica Emma

2017-01-01

This cross-sectional study investigated the age-related differences in dual-task performance both in mobility and cognitive tasks and the additive dual-task costs in a sample of older, middle-aged and young adults. 74 older adults (M = 72.63±5.57 years), 58 middle-aged adults (M = 46.69±4.68 years) and 63 young adults (M = 25.34±3.00 years) participated in the study. Participants performed different mobility and subtraction tasks under both single- and dual-task conditions. Linear regressions, repeated-measures and one-way analyses of covariance were used, The results showed: significant effects of the age on the dual and mobility tasks (p<0.05) and differences among the age-groups in the combined dual-task costs (p<0.05); significant decreases in mobility performance under dual-task conditions in all groups (p<0.05) and a decrease in cognitive performance in the older group (p<0.05). Dual-task activity affected mobility and cognitive performance, especially in older adults who showed a higher dual-task cost, suggesting that dual-tasks activities are affected by the age and consequently also mobility and cognitive tasks are negatively influenced. PMID:28732080

Gait and Cognition: A Complementary Approach to Understanding Brain Function and the Risk of Falling

PubMed Central

Montero-Odasso, Manuel; Verghese, Joe; Beauchet, Olivier; Hausdorff, Jeffrey M.

2012-01-01

Until recently, clinicians and researchers have performed gait assessments and cognitive assessments separately when evaluating older adults. Increasing evidence from clinical practice, epidemiological studies, and clinical trials shows that gait and cognition are inter-related in older adults. Quantifiable alterations in gait among older adults are associated with falls, dementia, and disability. At the same time, emerging evidence indicates that early disturbances in cognitive processes such as attention, executive function, and working memory are associated with slower gait and gait instability during single and dual-task testing, and that these cognitive disturbances assist in the prediction of future mobility loss, falls, and progression to dementia. This paper reviews the importance of the gait-cognition inter-relationship in aging and presents evidence that gait assessments can provide a window into the understanding of cognitive function and dysfunctions, and fall risk in older people in clinical practice. To this end, the benefits of dual-task gait assessments (e.g., walking while performing an attention-demanding task) as a marker of fall risk are summarized. Further, we also present a potential complementary approach for reducing the risk of falls by improving certain aspects of cognition through both non-pharmacological and pharmacological treatments. Untangling the relationship between early gait disturbances and early cognitive changes may be helpful for identifying older adults at higher risk of experiencing mobility decline, falls and the progression to dementia. PMID:23110433

Cerebellum and Integration of Neural Networks in Dual-Task Processing

PubMed Central

Wu, Tao; Liu, Jun; Hallett, Mark; Zheng, Zheng; Chan, Piu

2014-01-01

Performing two tasks simultaneously (dual-task) is common in human daily life. The neural correlates of dual-task processing remain unclear. In the current study, we used a dual motor and counting task with functional MRI (fMRI) to determine whether there are any areas additionally activated for dual-task performance. Moreover, we investigated the functional connectivity of these added activated areas, as well as the training effect on brain activity and connectivity. We found that the right cerebellar vermis, left lobule V of the cerebellar anterior lobe and precuneus are additionally activated for this type of dual-tasking. These cerebellar regions had functional connectivity with extensive motor- and cognitive-related regions. Dual-task training induced less activation in several areas, but increased the functional connectivity between these cerebellar regions and numbers of motor- and cognitive-related areas. Our findings demonstrate that some regions within the cerebellum can be additionally activated with dual-task performance. Their role in dual motor and cognitive task processes is likely to integrate motor and cognitive networks, and may be involved in adjusting these networks to be more efficient in order to perform dual-tasking properly. The connectivity of the precuneus differs from the cerebellar regions. A possible role of the precuneus in dual-task may be monitoring the operation of active brain networks. PMID:23063842

The effect of single-task and dual-task balance exercise programs on balance performance in adults with osteoporosis: a randomized controlled preliminary trial.

PubMed

Konak, H E; Kibar, S; Ergin, E S

2016-11-01

Osteoporosis is a serious disease characterized by muscle weakness in the lower extremities, shortened length of trunk, and increased dorsal kyphosis leading to poor balance performance. Although balance impairment increases in adults with osteoporosis, falls and fall-related injuries have been shown to occur mainly during the dual-task performance. Several studies have shown that dual-task performance was improved with specific repetitive dual-task exercises. The aims of this study were to compare the effect of single- and dual-task balance exercise programs on static balance, dynamic balance, and activity-specific balance confidence in adults with osteoporosis and to assess the effectiveness of dual-task balance training on gait speed under dual-task conditions. Older adults (N = 42) (age range, 45-88 years) with osteoporosis were randomly assigned into two groups. Single-task balance training group was given single-task balance exercises for 4 weeks, whereas dual-task balance training group received dual-task balance exercises. Participants received 45-min individualized training session, three times a week. Static balance was evaluated by one-leg stance (OLS) and a kinesthetic ability trainer (KAT) device. Dynamic balance was measured by the Berg Balance Scale (BBS), Time Up and Go (TUG) test, and gait speed. Self-confidence was assessed with the Activities-specific Balance Confidence (ABC-6) scale. Assessments were performed at baseline and after the 4-week program. At the end of the treatment periods, KAT score, BBS score, time in OLS and TUG, gait speeds under single- and dual-task conditions, and ABC-6 scale scores improved significantly in all patients (p < 0.05). However, BBS and gait speeds under single- and dual-task conditions showed significantly greater improvement in the dual-task balance training group than in the single-task balance training group (p < 0.05). ABC-6 scale scores improved more in the single-task balance training group than in the dual-task balance training group (p < 0.05). A 4-week single- and dual-task balance exercise programs are effective in improving static balance, dynamic balance, and balance confidence during daily activities in older adults with osteoporosis. However, single- and dual-task gait speeds showed greater improvement following the application of a specific type of dual-task exercise programs. 24102014-2.

Speech Motor Sequence Learning: Effect of Parkinson Disease and Normal Aging on Dual-Task Performance.

PubMed

Whitfield, Jason A; Goberman, Alexander M

2017-06-22

Everyday communication is carried out concurrently with other tasks. Therefore, determining how dual tasks interfere with newly learned speech motor skills can offer insight into the cognitive mechanisms underlying speech motor learning in Parkinson disease (PD). The current investigation examines a recently learned speech motor sequence under dual-task conditions. A previously learned sequence of 6 monosyllabic nonwords was examined using a dual-task paradigm. Participants repeated the sequence while concurrently performing a visuomotor task, and performance on both tasks was measured in single- and dual-task conditions. The younger adult group exhibited little to no dual-task interference on the accuracy and duration of the sequence. The older adult group exhibited variability in dual-task costs, with the group as a whole exhibiting an intermediate, though significant, amount of dual-task interference. The PD group exhibited the largest degree of bidirectional dual-task interference among all the groups. These data suggest that PD affects the later stages of speech motor learning, as the dual-task condition interfered with production of the recently learned sequence beyond the effect of normal aging. Because the basal ganglia is critical for the later stages of motor sequence learning, the observed deficits may result from the underlying neural dysfunction associated with PD.

Working Memory Training Improves Dual-Task Performance on Motor Tasks.

PubMed

Kimura, Takehide; Kaneko, Fuminari; Nagahata, Keita; Shibata, Eriko; Aoki, Nobuhiro

2017-01-01

The authors investigated whether working memory training improves motor-motor dual-task performance consisted of upper and lower limb tasks. The upper limb task was a simple reaction task and the lower limb task was an isometric knee extension task. 45 participants (age = 21.8 ± 1.6 years) were classified into a working memory training group (WM-TRG), dual-task training group, or control group. The training duration was 2 weeks (15 min, 4 times/week). Our results indicated that working memory capacity increased significantly only in the WM-TRG. Dual-task performance improved in the WM-TRG and dual-task training group. Our study provides the novel insight that working memory training improves dual-task performance without specific training on the target motor task.

Effect of a dual-task net-step exercise on cognitive and gait function in older adults.

PubMed

Kitazawa, Kazutoshi; Showa, Satoko; Hiraoka, Akira; Fushiki, Yasuhiro; Sakauchi, Humio; Mori, Mitsuru

2015-01-01

Participation in generally recommended aerobics or strength exercises may be challenging for older adults. Therefore, it is necessary to consider the types and levels of physical activities suited for them to improve their cognitive and gait function and adherence to exercise programs. This has prompted efforts to identify exercises that require less physical strength and frequency of performance, while still offering cognitive and health benefits. Here, we aimed to assess the effect of a novel dual-task net-step exercise (NSE) performed once a week for 8 consecutive weeks on improvements in cognitive performance and gait function in an older population. In this pretest/posttest experimental case control study, 60 healthy older adults (mean age 76.4 years) were recruited from community-dwelling people and separated randomly into 2 groups: a dual-task NSE group and a control group. The NSE group was asked to walk across a net without stepping on the ropes or being caught in the net. Two computer panel-type cognitive functional assessments, the Touch-M and Touch Panel-Type Dementia Assessment Scale, were administered at baseline and after 8 weeks of intervention to determine the effects of NSE. Improvements in gait function were also evaluated using Timed Up and Go test scores. Mixed-effect models with repeated measures (group × time) (analysis of variance, F test) were used to test the effects of NSE. Adjustments were made for covariates including age and sex (analysis of covariance). The NSE group showed significant improvement in cognitive performance (6.8% change; total Touch-M score 5.4 points; P = .04) and gait performance (11.5% change; Timed Up and Go time -0.98 second; P < .001) over the 8-week period. In the control group, there was no significant improvement. This study shows that dual-task NSE is capable of improving cognitive and gait performance in healthy older adults. Our results indicate that NSE offers an option for a large segment of the older population who need an easier way to maintain their cognitive health and gait function.

The Effects of Walking Workstations on Biomechanical Performance.

PubMed

Grindle, Daniel M; Baker, Lauren; Furr, Mike; Puterio, Tim; Knarr, Brian; Higginson, Jill

2018-04-03

Prolonged sitting has been associated with negative health effects. Walking workstations have become increasingly popular in the workplace. There is a lack of research on the biomechanical effect of walking workstations. This study analyzed whether walking while working alters normal gait patterns. Nine participants completed four walking trials at 2.4 km·h -1 and 4.0 km·h -1 : baseline walking condition, walking while performing a math task, a reading task, and a typing task. Biomechanical data were collected using standard motion capture procedures. The first maximum vertical ground reaction force, stride width, stride length, minimum toe clearance, peak swing hip abduction and flexion angles, peak swing and stance ankle dorsiflexion and knee flexion angles were analyzed. Differences between conditions were evaluated using analysis of variance tests with Bonferroni correction (p ≤ 0.05). Stride width decreased during the reading task at both speeds. Although other parameters exhibited significant differences when multitasking, these changes were within the normal range of gait variability. It appears that for short periods, walking workstations do not negatively impact gait in healthy young adults.

Walking with eyes closed is easier than walking with eyes open without visual cues: The Romberg task versus the goggle task.

PubMed

Yelnik, A P; Tasseel Ponche, S; Andriantsifanetra, C; Provost, C; Calvalido, A; Rougier, P

2015-12-01

The Romberg test, with the subject standing and with eyes closed, gives diagnostic arguments for a proprioceptive disorder. Closing the eyes is also used in balance rehabilitation as a main way to stimulate neural plasticity with proprioceptive, vestibular and even cerebellar disorders. Nevertheless, standing and walking with eyes closed or with eyes open in the dark are certainly 2 different tasks. We aimed to compare walking with eyes open, closed and wearing black or white goggles in healthy subjects. A total of 50 healthy participants were randomly divided into 2 protocols and asked to walk on a 5-m pressure-sensitive mat, under 3 conditions: (1) eyes open (EO), eyes closed (EC) and eyes open with black goggles (BG) and (2) EO, EO with BG and with white goggles (WG). Gait was described by velocity (m·s(-1)), double support (% gait cycle), gait variability index (GVI/100) and exit from the mat (%). Analysis involved repeated measures Anova, Holm-Sidak's multiple comparisons test for parametric parameters (GVI) and Dunn's multiple comparisons test for non-parametric parameters. As compared with walking with EC, walking with BG produced lower median velocity, by 6% (EO 1.26; BG 1.01 vs EC 1.07 m·s(-1), P=0.0328), and lower mean GVI, by 8% (EO 91.8; BG 66.8 vs EC 72.24, P=0.009). Parameters did not differ between walking under the BG and WG conditions. The goggle task increases the difficulty in walking with visual deprivation compared to the Romberg task, so the goggle task can be proposed to gradually increase the difficulty in walking with visual deprivation (from eyes closed to eyes open in black goggles). Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Performance Enhancements Under Dual-task Conditions

NASA Technical Reports Server (NTRS)

Kramer, A. F.; Wickens, C. D.; Donchin, E.

1984-01-01

Research on dual-task performance has been concerned with delineating the antecedent conditions which lead to dual-task decrements. Capacity models of attention, which propose that a hypothetical resource structure underlies performance, have been employed as predictive devices. These models predict that tasks which require different processing resources can be more successfully time shared than tasks which require common resources. The conditions under which such dual-task integrality can be fostered were assessed in a study in which three factors likely to influence the integrality between tasks were manipulated: inter-task redundancy, the physical proximity of tasks and the task relevant objects. Twelve subjects participated in three experimental sessions in which they performed both single and dual-tasks. The primary task was a pursuit step tracking task. The secondary tasks required the discrimination between different intensities or different spatial positions of a stimulus. The results are discussed in terms of a model of dual-task integrality.

Aging and the Vulnerability of Speech to Dual Task Demands

PubMed Central

Kemper, Susan; Schmalzried, RaLynn; Hoffman, Lesa; Herman, Ruth

2010-01-01

Tracking a digital pursuit rotor task was used to measure dual task costs of language production by young and older adults. Tracking performance by both groups was affected by dual task demands: time on target declined and tracking error increased as dual task demands increased from the baseline condition to a moderately demanding dual task condition to a more demanding dual task condition. When dual task demands were moderate, older adults’ speech rate declined but their fluency, grammatical complexity, and content were unaffected. When the dual task was more demanding, older adults’ speech, like young adults’ speech, became highly fragmented, ungrammatical, and incoherent. Vocabulary, working memory, processing speed, and inhibition affected vulnerability to dual task costs: vocabulary provided some protection for sentence length and grammaticality, working memory conferred some protection for grammatical complexity, and processing speed provided some protection for speech rate, propositional density, coherence, and lexical diversity. Further, vocabulary and working memory capacity provided more protection for older adults than for young adults although the protective effect of processing speed was somewhat reduced for older adults as compared to the young adults. PMID:21186917

Effects of dual tasks and dual-task training on postural stability: a systematic review and meta-analysis

PubMed Central

Ghai, Shashank; Ghai, Ishan; Effenberg, Alfred O

2017-01-01

The use of dual-task training paradigm to enhance postural stability in patients with balance impairments is an emerging area of interest. The differential effects of dual tasks and dual-task training on postural stability still remain unclear. A systematic review and meta-analysis were conducted to analyze the effects of dual task and training application on static and dynamic postural stability among various population groups. Systematic identification of published literature was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, from inception until June 2016, on the online databases Scopus, PEDro, MEDLINE, EMBASE, and SportDiscus. Experimental studies analyzing the effects of dual task and dual-task training on postural stability were extracted, critically appraised using PEDro scale, and then summarized according to modified PEDro level of evidence. Of 1,284 records, 42 studies involving 1,480 participants met the review’s inclusion criteria. Of the studies evaluating the effects of dual-task training on postural stability, 87.5% of the studies reported significant enhancements, whereas 30% of the studies evaluating acute effects of dual tasks on posture reported significant enhancements, 50% reported significant decrements, and 20% reported no effects. Meta-analysis of the pooled studies revealed moderate but significant enhancements of dual-task training in elderly participants (95% CI: 1.16–2.10) and in patients suffering from chronic stroke (−0.22 to 0.86). The adverse effects of complexity of dual tasks on postural stability were also revealed among patients with multiple sclerosis (−0.74 to 0.05). The review also discusses the significance of verbalization in a dual-task setting for increasing cognitive–motor interference. Clinical implications are discussed with respect to practical applications in rehabilitation settings. PMID:28356727

Effects of dual tasks and dual-task training on postural stability: a systematic review and meta-analysis.

PubMed

Ghai, Shashank; Ghai, Ishan; Effenberg, Alfred O

2017-01-01

The use of dual-task training paradigm to enhance postural stability in patients with balance impairments is an emerging area of interest. The differential effects of dual tasks and dual-task training on postural stability still remain unclear. A systematic review and meta-analysis were conducted to analyze the effects of dual task and training application on static and dynamic postural stability among various population groups. Systematic identification of published literature was performed adhering to Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, from inception until June 2016, on the online databases Scopus, PEDro, MEDLINE, EMBASE, and SportDiscus. Experimental studies analyzing the effects of dual task and dual-task training on postural stability were extracted, critically appraised using PEDro scale, and then summarized according to modified PEDro level of evidence. Of 1,284 records, 42 studies involving 1,480 participants met the review's inclusion criteria. Of the studies evaluating the effects of dual-task training on postural stability, 87.5% of the studies reported significant enhancements, whereas 30% of the studies evaluating acute effects of dual tasks on posture reported significant enhancements, 50% reported significant decrements, and 20% reported no effects. Meta-analysis of the pooled studies revealed moderate but significant enhancements of dual-task training in elderly participants (95% CI: 1.16-2.10) and in patients suffering from chronic stroke (-0.22 to 0.86). The adverse effects of complexity of dual tasks on postural stability were also revealed among patients with multiple sclerosis (-0.74 to 0.05). The review also discusses the significance of verbalization in a dual-task setting for increasing cognitive-motor interference. Clinical implications are discussed with respect to practical applications in rehabilitation settings.

Reliability and Concurrent Validity of the Narrow Path Walking Test in Persons With Multiple Sclerosis.

PubMed

Rosenblum, Uri; Melzer, Itshak

2017-01-01

About 90% of people with multiple sclerosis (PwMS) have gait instability and 50% fall. Reliable and clinically feasible methods of gait instability assessment are needed. The study investigated the reliability and validity of the Narrow Path Walking Test (NPWT) under single-task (ST) and dual-task (DT) conditions for PwMS. Thirty PwMS performed the NPWT on 2 different occasions, a week apart. Number of Steps, Trial Time, Trial Velocity, Step Length, Number of Step Errors, Number of Cognitive Task Errors, and Number of Balance Losses were measured. Intraclass correlation coefficients (ICC2,1) were calculated from the average values of NPWT parameters. Absolute reliability was quantified from standard error of measurement (SEM) and smallest real difference (SRD). Concurrent validity of NPWT with Functional Reach Test, Four Square Step Test (FSST), 12-item Multiple Sclerosis Walking Scale (MSWS-12), and 2 Minute Walking Test (2MWT) was determined using partial correlations. Intraclass correlation coefficients (ICCs) for most NPWT parameters during ST and DT ranged from 0.46-0.94 and 0.55-0.95, respectively. The highest relative reliability was found for Number of Step Errors (ICC = 0.94 and 0.93, for ST and DT, respectively) and Trial Velocity (ICC = 0.83 and 0.86, for ST and DT, respectively). Absolute reliability was high for Number of Step Errors in ST (SEM % = 19.53%) and DT (SEM % = 18.14%) and low for Trial Velocity in ST (SEM % = 6.88%) and DT (SEM % = 7.29%). Significant correlations for Number of Step Errors and Trial Velocity were found with FSST, MSWS-12, and 2MWT. In persons with PwMS performing the NPWT, Number of Step Errors and Trial Velocity were highly reliable parameters. Based on correlations with other measures of gait instability, Number of Step Errors was the most valid parameter of dynamic balance under the conditions of our test.Video Abstract available for more insights from the authors (see Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A159).

Age differences between children and young adults in the dynamics of dual-task prioritization: body (balance) versus mind (memory).

PubMed

Schaefer, Sabine; Krampe, Ralf Th; Lindenberger, Ulman; Baltes, Paul B

2008-05-01

Task prioritization can lead to trade-off patterns in dual-task situations. The authors compared dual-task performances in 9- and 11-year-old children and young adults performing a cognitive task and a motor task concurrently. The motor task required balancing on an ankle-disc board. Two cognitive tasks measured working memory and episodic memory at difficulty levels individually adjusted during the course of extensive training. Adults showed performance decrements in both task domains under dual-task conditions. In contrast, children showed decrements only in the cognitive tasks but actually swayed less under dual-task than under single-task conditions and continued to reduce their body sway even when instructed to focus on the cognitive task. The authors argue that children perform closer to their stability boundaries in the balance task and therefore prioritize protection of their balance under dual-task conditions. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

Dual-task testing to predict falls in community-dwelling older adults: a systematic review.

PubMed

Muir-Hunter, S W; Wittwer, J E

2016-03-01

Cognitive impairment increases fall risk in older adults. Dual-task testing is an accepted way to assess the interaction between cognition and mobility; however, there is a lack of evidence-based recommendations for dual-task testing to evaluate fall risk in clinical practice. To evaluate the association between dual-task testing protocols and future fall risk, and to identify the specific dual-task test protocols associated with elevated risk. MEDLINE, Pubmed and EMBASE electronic databases were searched from January 1988 to September 2013. Two independent raters identified prospective cohort studies (duration of at least 1 year) of dual-task assessment in community-dwelling participants aged ≥60 years, with 'falls' as the primary outcome. Methodological quality was scored independently by two raters using a published checklist of criteria for evaluating threats to the validity of observational studies. Deterioration in gait during dual-task testing compared with single-task performance was associated with increased fall risk. Shortcomings within the literature significantly limit knowledge translation of dual-task gait protocols into clinical practice. There is a paucity of prospective studies on the association of dual-task gait assessment with fall risk. Changes in gait under dual-task testing are associated with future fall risk, and this association is stronger than that for single-task conditions. Limitations in the available literature preclude development of detailed recommendations for dual-task gait testing procedures in clinical practice to identify and stratify fall risk in older adults. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

Neural correlates of motor-cognitive dual-tasking in young and old adults

PubMed Central

Papegaaij, Selma; Hortobágyi, Tibor; Godde, Ben; Kaan, Wim A.; Erhard, Peter; Voelcker-Rehage, Claudia

2017-01-01

When two tasks are performed simultaneously, performance often declines in one or both tasks. These so-called dual-task costs are more pronounced in old than in young adults. One proposed neurological mechanism of the dual-task costs is that old compared with young adults tend to execute single-tasks with higher brain activation. In the brain regions that are needed for both tasks, the reduced residual capacity may interfere with performance of the dual-task. This competition for shared brain regions has been called structural interference. The purpose of the study was to determine whether structural interference indeed plays a role in the age-related decrease in dual-task performance. Functional magnetic resonance imaging (fMRI) was used to investigate 23 young adults (20–29 years) and 32 old adults (66–89 years) performing a calculation (serial subtraction by seven) and balance-simulation (plantar flexion force control) task separately or simultaneously. Behavioral performance decreased during the dual-task compared with the single-tasks in both age groups, with greater dual-task costs in old compared with young adults. Brain activation was significantly higher in old than young adults during all conditions. Region of interest analyses were performed on brain regions that were active in both tasks. Structural interference was apparent in the right insula, as quantified by an age-related reduction in upregulation of brain activity from single- to dual-task. However, the magnitude of upregulation did not correlate with dual-task costs. Therefore, we conclude that the greater dual-task costs in old adults were probably not due to increased structural interference. PMID:29220349

Unexpected perturbations training improves balance control and voluntary stepping times in older adults - a double blind randomized control trial.

PubMed

Kurz, Ilan; Gimmon, Yoav; Shapiro, Amir; Debi, Ronen; Snir, Yoram; Melzer, Itshak

2016-03-04

Falls are common among elderly, most of them occur while slipping or tripping during walking. We aimed to explore whether a training program that incorporates unexpected loss of balance during walking able to improve risk factors for falls. In a double-blind randomized controlled trial 53 community dwelling older adults (age 80.1±5.6 years), were recruited and randomly allocated to an intervention group (n = 27) or a control group (n = 26). The intervention group received 24 training sessions over 3 months that included unexpected perturbation of balance exercises during treadmill walking. The control group performed treadmill walking with no perturbations. The primary outcome measures were the voluntary step execution times, traditional postural sway parameters and Stabilogram-Diffusion Analysis. The secondary outcome measures were the fall efficacy Scale (FES), self-reported late life function (LLFDI), and Performance-Oriented Mobility Assessment (POMA). Compared to control, participation in intervention program that includes unexpected loss of balance during walking led to faster Voluntary Step Execution Times under single (p = 0.002; effect size [ES] =0.75) and dual task (p = 0.003; [ES] = 0.89) conditions; intervention group subjects showed improvement in Short-term Effective diffusion coefficients in the mediolateral direction of the Stabilogram-Diffusion Analysis under eyes closed conditions (p = 0.012, [ES] = 0.92). Compared to control there were no significant changes in FES, LLFDI, and POMA. An intervention program that includes unexpected loss of balance during walking can improve voluntary stepping times and balance control, both previously reported as risk factors for falls. This however, did not transferred to a change self-reported function and FES. ClinicalTrials.gov NCT01439451 .

Dual Task of Fine Motor Skill and Problem Solving in Individuals With Multiple Sclerosis: A Pilot Study.

PubMed

Goverover, Y; Sandroff, B M; DeLuca, J

2018-04-01

To (1) examine and compare dual-task performance in patients with multiple sclerosis (MS) and healthy controls (HCs) using mathematical problem-solving questions that included an everyday competence component while performing an upper extremity fine motor task; and (2) examine whether difficulties in dual-task performance are associated with problems in performing an everyday internet task. Pilot study, mixed-design with both a within and between subjects' factor. A nonprofit rehabilitation research institution and the community. Participants (N=38) included persons with MS (n=19) and HCs (n=19) who were recruited from a nonprofit rehabilitation research institution and from the community. Not applicable. Participant were presented with 2 testing conditions: (1) solving mathematical everyday problems or placing bolts into divots (single-task condition); and (2) solving problems while putting bolts into divots (dual-task condition). Additionally, participants were required to perform a test of everyday internet competence. As expected, dual-task performance was significantly worse than either of the single-task tasks (ie, number of bolts into divots or correct answers, and time to answer the questions). Cognitive but not motor dual-task cost was associated with worse performance in activities of everyday internet tasks. Cognitive dual-task cost is significantly associated with worse performance of everyday technology. This was not observed in the motor dual-task cost. The implications of dual-task costs on everyday activity are discussed. Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Dual Motor-Cognitive Virtual Reality Training Impacts Dual-Task Performance in Freezing of Gait.

PubMed

Killane, Isabelle; Fearon, Conor; Newman, Louise; McDonnell, Conor; Waechter, Saskia M; Sons, Kristian; Lynch, Timothy; Reilly, Richard B

2015-11-01

Freezing of gait (FOG), an episodic gait disturbance characterized by the inability to generate effective stepping, occurs in more than half of Parkinson's disease patients. It is associated with both executive dysfunction and attention and becomes most evident during dual tasking (performing two tasks simultaneously). This study examined the effect of dual motor-cognitive virtual reality training on dual-task performance in FOG. Twenty community dwelling participants with Parkinson's disease (13 with FOG, 7 without FOG) participated in a pre-assessment, eight 20-minute intervention sessions, and a post-assessment. The intervention consisted of a virtual reality maze (DFKI, Germany) through which participants navigated by stepping-in-place on a balance board (Nintendo, Japan) under time pressure. This was combined with a cognitive task (Stroop test), which repeatedly divided participants' attention. The primary outcome measures were pre- and post-intervention differences in motor (stepping time, symmetry, rhythmicity) and cognitive (accuracy, reaction time) performance during single- and dual-tasks. Both assessments consisted of 1) a single cognitive task 2) a single motor task, and 3) a dual motor-cognitive task. Following the intervention, there was significant improvement in dual-task cognitive and motor parameters (stepping time and rhythmicity), dual-task effect for those with FOG and a noteworthy improvement in FOG episodes. These improvements were less significant for those without FOG. This is the first study to show benefit of a dual motor-cognitive approach on dual-task performance in FOG. Advances in such virtual reality interventions for home use could substantially improve the quality of life for patients who experience FOG.

Mechanisms of Practice-Related Reductions of Dual-Task Interference with Simple Tasks: Data and Theory

PubMed Central

Strobach, Tilo; Torsten, Schubert

2017-01-01

In dual-task situations, interference between two simultaneous tasks impairs performance. With practice, however, this impairment can be reduced. To identify mechanisms leading to a practice-related improvement in sensorimotor dual tasks, the present review applied the following general hypothesis: Sources that impair dual-task performance at the beginning of practice are associated with mechanisms for the reduction of dual-task impairment at the end of practice. The following types of processes provide sources for the occurrence of this impairment: (a) capacity-limited processes within the component tasks, such as response-selection or motor response stages, and (b) cognitive control processes independent of these tasks and thus operating outside of component-task performance. Dual-task practice studies show that, under very specific conditions, capacity-limited processes within the component tasks are automatized with practice, reducing the interference between two simultaneous tasks. Further, there is evidence that response-selection stages are shortened with practice. Thus, capacity limitations at these stages are sources for dual-task costs at the beginning of practice and are overcome with practice. However, there is no evidence demonstrating the existence of practice-related mechanisms associated with capacity-limited motor-response stages. Further, during practice, there is an acquisition of executive control skills for an improved allocation of limited attention resources to two tasks as well as some evidence supporting the assumption of improved task coordination. These latter mechanisms are associated with sources of dual-task interference operating outside of component task performance at the beginning of practice and also contribute to the reduction of dual-task interference at its end. PMID:28439319

Investigation on the improvement and transfer of dual-task coordination skills.

PubMed

Strobach, Tilo; Frensch, Peter A; Soutschek, Alexander; Schubert, Torsten

2012-11-01

Recent research has demonstrated that dual-task performance in situations with two simultaneously presented tasks can be substantially improved with extensive practice. This improvement was related to the acquisition of task coordination skills. Earlier studies provided evidence that these skills result from hybrid practice, including dual and single tasks, but not from single-task practice. It is an open question, however, whether task coordination skills are independent from the specific practice situation and are transferable to new situations or whether they are non-transferable and task-specific. The present study, therefore, tested skill transfer in (1) a dual-task situation with identical tasks in practice and transfer, (2) a dual-task situation with two tasks changed from practice to transfer, and (3) a task switching situation with two sequentially presented tasks. Our findings are largely consistent with the assumption that task coordination skills are non-transferable and task-specific. We cannot, however, definitively reject the assumption of transferable skills when measuring error rates in the dual-task situation with two changed tasks after practice. In the task switching situation, single-task and hybrid practice both led to a transfer effect on mixing costs.

Pilot study of atomoxetine in patients with Parkinson's disease and dopa-unresponsive Freezing of Gait.

PubMed

Revuelta, Gonzalo J; Embry, Aaron; Elm, Jordan J; Gregory, Chris; Delambo, Amy; Kautz, Steve; Hinson, Vanessa K

2015-01-01

Freezing of gait (FoG) is a common and debilitating condition in Parkinson's disease (PD) associated with executive dysfunction. A subtype of FoG does not respond to dopaminergic therapy and may be related to noradrenergic deficiency. This pilot study explores the effects of atomoxetine on gait in PD patients with dopa-unresponsive FoG using a novel paradigm for objective gait assessment. Ten patients with PD and dopa-unresponsive FoG were enrolled in this eight-week open label pilot study. Assessments included an exploratory gait analysis protocol that quantified spatiotemporal parameters during straight-away walking and turning, while performing a dual task. Clinical, and subjective assessments of gait, quality of life, and safety were also administered. The primary outcome was a validated subjective assessment for FoG (FOG-Q). Atomoxetine was well tolerated, however, no significant change was observed in the primary outcome. The gait analysis protocol correlated well with clinical scales, but not with subjective assessments. DBS patients were more likely to increase gait velocity (p = 0.033), and improved in other clinical assessments. Objective gait analysis protocols assessing gait while dual tasking are feasible and useful for this patient population, and may be superior correlates of FoG severity than subjective measures. These findings can inform future trials in this population.

Upper-Extremity Dual-Task Function: An Innovative Method to Assess Cognitive Impairment in Older Adults.

PubMed

Toosizadeh, Nima; Najafi, Bijan; Reiman, Eric M; Mager, Reine M; Veldhuizen, Jaimeson K; O'Connor, Kathy; Zamrini, Edward; Mohler, Jane

2016-01-01

Difficulties in orchestrating simultaneous tasks (i.e., dual-tasking) have been associated with cognitive impairments in older adults. Gait tests have been commonly used as the motor task component for dual-task assessments; however, many older adults have mobility impairments or there is a lack of space in busy clinical settings. We assessed an upper-extremity function (UEF) test as an alternative motor task to study the dual-task motor performance in older adults. Older adults (≥65 years) were recruited, and cognitive ability was measured using the Montreal cognitive assessment (MoCA). Participants performed repetitive elbow flexion with their maximum pace, once single-task, and once while counting backward by one (dual-task). Single- and dual-task gait tests were also performed with normal speed. Three-dimensional kinematics was measured both from upper-extremity and lower-extremity using wearable sensors to determine UEF and gait parameters. Parameters were compared between the cognitively impaired and healthy groups using analysis of variance tests, while controlling for age, gender, and body mass index (BMI). Correlations between UEF and gait parameters for dual-task and dual-task cost were assessed using linear regression models. Sixty-seven older adults were recruited (age = 83 ± 10 years). Based on MoCA, 10 (15%) were cognitively impaired. While no significant differences were observed in the single-task condition, within the dual-task condition, the cognitively impaired group showed significantly less arm flexion speed (62%, d = 1.51, p = 0.02) and range of motion (27%, d = 0.93, p = 0.04), and higher speed variability (88%, d = 1.82, p < 0.0001) compared to the cognitively intact group, when adjusted with age, gender, and BMI. Significant correlations were observed between UEF speed parameters and gait stride velocity for dual-task condition (r = 0.55, p < 0.0001) and dual-task cost (r = 0.28, p = 0.03). We introduced a novel test for assessing dual-task performance in older adults that lasts 20 s and is based on upper-extremity function. Our results confirm significant associations between upper-extremity speed, range of motion, and speed variability with both the MoCA score and the gait performance within the dual-task condition.

Upper-Extremity Dual-Task Function: An Innovative Method to Assess Cognitive Impairment in Older Adults

PubMed Central

Toosizadeh, Nima; Najafi, Bijan; Reiman, Eric M.; Mager, Reine M.; Veldhuizen, Jaimeson K.; O’Connor, Kathy; Zamrini, Edward; Mohler, Jane

2016-01-01

Background: Difficulties in orchestrating simultaneous tasks (i.e., dual-tasking) have been associated with cognitive impairments in older adults. Gait tests have been commonly used as the motor task component for dual-task assessments; however, many older adults have mobility impairments or there is a lack of space in busy clinical settings. We assessed an upper-extremity function (UEF) test as an alternative motor task to study the dual-task motor performance in older adults. Methods: Older adults (≥65 years) were recruited, and cognitive ability was measured using the Montreal cognitive assessment (MoCA). Participants performed repetitive elbow flexion with their maximum pace, once single-task, and once while counting backward by one (dual-task). Single- and dual-task gait tests were also performed with normal speed. Three-dimensional kinematics was measured both from upper-extremity and lower-extremity using wearable sensors to determine UEF and gait parameters. Parameters were compared between the cognitively impaired and healthy groups using analysis of variance tests, while controlling for age, gender, and body mass index (BMI). Correlations between UEF and gait parameters for dual-task and dual-task cost were assessed using linear regression models. Results: Sixty-seven older adults were recruited (age = 83 ± 10 years). Based on MoCA, 10 (15%) were cognitively impaired. While no significant differences were observed in the single-task condition, within the dual-task condition, the cognitively impaired group showed significantly less arm flexion speed (62%, d = 1.51, p = 0.02) and range of motion (27%, d = 0.93, p = 0.04), and higher speed variability (88%, d = 1.82, p < 0.0001) compared to the cognitively intact group, when adjusted with age, gender, and BMI. Significant correlations were observed between UEF speed parameters and gait stride velocity for dual-task condition (r = 0.55, p < 0.0001) and dual-task cost (r = 0.28, p = 0.03). Conclusion: We introduced a novel test for assessing dual-task performance in older adults that lasts 20 s and is based on upper-extremity function. Our results confirm significant associations between upper-extremity speed, range of motion, and speed variability with both the MoCA score and the gait performance within the dual-task condition. PMID:27458374

Self-reported walking ability predicts functional mobility performance in frail older adults.

PubMed

Alexander, N B; Guire, K E; Thelen, D G; Ashton-Miller, J A; Schultz, A B; Grunawalt, J C; Giordani, B

2000-11-01

To determine how self-reported physical function relates to performance in each of three mobility domains: walking, stance maintenance, and rising from chairs. Cross-sectional analysis of older adults. University-based laboratory and community-based congregate housing facilities. Two hundred twenty-one older adults (mean age, 79.9 years; range, 60-102 years) without clinical evidence of dementia (mean Folstein Mini-Mental State score, 28; range, 24-30). We compared the responses of these older adults on a questionnaire battery used by the Established Populations for the Epidemiologic Study of the Elderly (EPESE) project, to performance on mobility tasks of graded difficulty. Responses to the EPESE battery included: (1) whether assistance was required to perform seven Katz activities of daily living (ADL) items, specifically with walking and transferring; (2) three Rosow-Breslau items, including the ability to walk up stairs and walk a half mile; and (3) five Nagi items, including difficulty stooping, reaching, and lifting objects. The performance measures included the ability to perform, and time taken to perform, tasks in three summary score domains: (1) walking ("Walking," seven tasks, including walking with an assistive device, turning, stair climbing, tandem walking); (2) stance maintenance ("Stance," six tasks, including unipedal, bipedal, tandem, and maximum lean); and (3) chair rise ("Chair Rise," six tasks, including rising from a variety of seat heights with and without the use of hands for assistance). A total score combines scores in each Walking, Stance, and Chair Rise domain. We also analyzed how cognitive/ behavioral factors such as depression and self-efficacy related to the residuals from the self-report and performance-based ANOVA models. Rosow-Breslau items have the strongest relationship with the three performance domains, Walking, Stance, and Chair Rise (eta-squared ranging from 0.21 to 0.44). These three performance domains are as strongly related to one Katz ADL item, walking (eta-squared ranging from 0.15 to 0.33) as all of the Katz ADL items combined (eta-squared ranging from 0.21 to 0.35). Tests of problem solving and psychomotor speed, the Trails A and Trails B tests, are significantly correlated with the residuals from the self-report and performance-based ANOVA models. Compared with the rest of the EPESE self-report items, self-report items related to walking (such as Katz walking and Rosow-Breslau items) are better predictors of functional mobility performance on tasks involving walking, stance maintenance, and rising from chairs. Compared with other self-report items, self-reported walking ability may be the best predictor of overall functional mobility.

Effects of dual-task training on balance and executive functions in Parkinson's disease: A pilot study.

PubMed

Fernandes, Ângela; Rocha, Nuno; Santos, Rubim; Tavares, João Manuel R S

2015-01-01

The aim of this study was to analyze the efficacy of cognitive-motor dual-task training compared with single-task training on balance and executive functions in individuals with Parkinson's disease. Fifteen subjects, aged between 39 and 75 years old, were randomly assigned to the dual-task training group (n = 8) and single-task training group (n = 7). The training was run twice a week for 6 weeks. The single-task group received balance training and the dual-task group performed cognitive tasks simultaneously with the balance training. There were no significant differences between the two groups at baseline. After the intervention, the results for mediolateral sway with eyes closed were significantly better for the dual-task group and anteroposterior sway with eyes closed was significantly better for the single-task group. The results suggest superior outcomes for the dual-task training compared to the single-task training for static postural control, except in anteroposterior sway with eyes closed.

Integrating the behavioral and neural dynamics of response selection in a dual-task paradigm: a dynamic neural field model of Dux et al. (2009).

PubMed

Buss, Aaron T; Wifall, Tim; Hazeltine, Eliot; Spencer, John P

2014-02-01

People are typically slower when executing two tasks than when only performing a single task. These dual-task costs are initially robust but are reduced with practice. Dux et al. (2009) explored the neural basis of dual-task costs and learning using fMRI. Inferior frontal junction (IFJ) showed a larger hemodynamic response on dual-task trials compared with single-task trial early in learning. As dual-task costs were eliminated, dual-task hemodynamics in IFJ reduced to single-task levels. Dux and colleagues concluded that the reduction of dual-task costs is accomplished through increased efficiency of information processing in IFJ. We present a dynamic field theory of response selection that addresses two questions regarding these results. First, what mechanism leads to the reduction of dual-task costs and associated changes in hemodynamics? We show that a simple Hebbian learning mechanism is able to capture the quantitative details of learning at both the behavioral and neural levels. Second, is efficiency isolated to cognitive control areas such as IFJ, or is it also evident in sensory motor areas? To investigate this, we restrict Hebbian learning to different parts of the neural model. None of the restricted learning models showed the same reductions in dual-task costs as the unrestricted learning model, suggesting that efficiency is distributed across cognitive control and sensory motor processing systems.

Walking while talking: Young adults flexibly allocate resources between speech and gait.

PubMed

Raffegeau, Tiphanie E; Haddad, Jeffrey M; Huber, Jessica E; Rietdyk, Shirley

2018-05-26

Walking while talking is an ideal multitask behavior to assess how young healthy adults manage concurrent tasks as it is well-practiced, cognitively demanding, and has real consequences for impaired performance in either task. Since the association between cognitive tasks and gait appears stronger when the gait task is more challenging, gait challenge was systematically manipulated in this study. To understand how young adults accomplish the multitask behavior of walking while talking as the gait challenge was systematically manipulated. Sixteen young adults (21 ± 1.6 years, 9 males) performed three gait tasks with and without speech: unobstructed gait (easy), obstacle crossing (moderate), obstacle crossing and tray carrying (difficult). Participants also provided a speech sample while seated for a baseline indicator of speech. The speech task was to speak extemporaneously about a topic (e.g. first car). Gait speed and the duration of silent pauses during speaking were determined. Silent pauses reflect cognitive processes involved in speech production and language planning. When speaking and walking without obstacles, gait speed decreased (relative to walking without speaking) but silent pause duration did not change (relative to seated speech). These changes are consistent with the idea that, in the easy gait task, participants placed greater value on speech pauses than on gait speed, likely due to the negative social consequences of impaired speech. In the moderate and difficult gait tasks both parameters changed: gait speed decreased and silent pauses increased. Walking while talking is a cognitively demanding task for healthy young adults, despite being a well-practiced habitual activity. These findings are consistent with the integrated model of task prioritization from Yogev-Seligmann et al., [1]. Copyright © 2018 Elsevier B.V. All rights reserved.

Modulating Arm Swing Symmetry with Cognitive Load: A Window on Rhythmic Spinal Locomotor Networks in Humans?

PubMed

Killeen, Tim; Easthope, Christopher S; Filli, Linard; Linnebank, Michael; Curt, Armin; Bolliger, Marc; Zörner, Björn

2017-05-15

In healthy subjects, changes in arm swing symmetry while walking are observed when a cognitive dual task is added, with a tendency toward left-dominant arm swing as cognitive load increases. We applied a modified Stroop word/color naming paradigm to investigate this effect in spinal cord injured (SCI) patients. Six patients with cervical SCI (cSCI), 6 with thoracic injuries (tSCI; all 12 patients American Spinal Injury Association [ASIA] Injury Score [AIS]D), and 12 healthy, matched controls underwent three-dimensional 3D gait analysis while walking normally at a comfortable speed (NW) and when performing an additional congruent (CS) and incongruent (IS) Stroop task. An arm swing symmetry index (ASI)-in which positive values indicate proportionally more movement on the left and vice versa-was calculated. Even in the baseline NW condition, all three subject groups showed larger arm movements on the left. In controls, ASI increased (NW, 13.7 ± 6.3; CS, 16.6 ± 6.4; IS, 19.6 ± 7.8) as the task became more demanding. A larger shift in tSCI patients (NW, 15.8 ± 6.0; CS, 23.4 ± 3.8; IS, 30.7 ± 4.4) was driven by a significant reduction in right wrist trajectory (p = 0.014), whereas cSCI patients showed a small reduction in mean ASI with high variability (NW, 14.2 ± 10.7; CS, 9.3 ± 13.5; IS, 6.0 ± 12.9). The effect of the IS task on ASI compared to baseline (NW) was significantly different between tSCI (+12.5 ± 6.3) and cSCI (-8.2 ± 6.0) patients (p = 0.011). Disruption of the long propriospinal connections coordinating arm and leg movements during walking may explain the heightened sensitivity to manipulation of cognitive load in tSCI, whereas the more robust automaticity in cSCI may be attributed to impaired supraspinal inputs in the context of preserved intraspinal pathways.

Motor-cognitive dual-task performance: effects of a concurrent motor task on distinct components of visual processing capacity.

PubMed

Künstler, E C S; Finke, K; Günther, A; Klingner, C; Witte, O; Bublak, P

2018-01-01

Dual tasking, or the simultaneous execution of two continuous tasks, is frequently associated with a performance decline that can be explained within a capacity sharing framework. In this study, we assessed the effects of a concurrent motor task on the efficiency of visual information uptake based on the 'theory of visual attention' (TVA). TVA provides parameter estimates reflecting distinct components of visual processing capacity: perceptual threshold, visual processing speed, and visual short-term memory (VSTM) storage capacity. Moreover, goodness-of-fit values and bootstrapping estimates were derived to test whether the TVA-model is validly applicable also under dual task conditions, and whether the robustness of parameter estimates is comparable in single- and dual-task conditions. 24 subjects of middle to higher age performed a continuous tapping task, and a visual processing task (whole report of briefly presented letter arrays) under both single- and dual-task conditions. Results suggest a decline of both visual processing capacity and VSTM storage capacity under dual-task conditions, while the perceptual threshold remained unaffected by a concurrent motor task. In addition, goodness-of-fit values and bootstrapping estimates support the notion that participants processed the visual task in a qualitatively comparable, although quantitatively less efficient way under dual-task conditions. The results support a capacity sharing account of motor-cognitive dual tasking and suggest that even performing a relatively simple motor task relies on central attentional capacity that is necessary for efficient visual information uptake.

Neuroticism related differences in the functional neuroanatomical correlates of multitasking. An fMRI study.

PubMed

Szameitat, Andre J; Saylik, Rahmi; Parton, Andrew

2016-12-02

It is known that neuroticism impairs cognitive performance mostly in difficult tasks, but not so much in easier tasks. One pervasive situation of this type is multitasking, in which the combination of two simple tasks creates a highly demanding dual-task, and consequently high neurotics show higher dual-task costs than low neurotics. However, the functional neuroanatomical correlates of these additional performance impairments in high neurotics are unknown. To test for this, we assessed brain activity by means of functional magnetic resonance imaging (fMRI) in 17 low and 15 high neurotics while they were performing a demanding dual-task and the less demanding component tasks as single-tasks. Behavioural results showed that performance (response times and error rates) was lower in the dual-task than in the single-tasks (dual-task costs), and that these dual-task costs were significantly higher in high neurotics. Imaging data showed that high neurotics showed less dual-task specific activation in lateral (mainly middle frontal gyrus) and medial prefrontal cortices. We conclude that high levels of neuroticism impair behavioural performance in demanding tasks, and that this impairment is accompanied by reduced activation of the task-associated brain areas. Copyright © 2016 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Toward an understanding of the neural mechanisms underlying dual-task performance: Contribution of comparative approaches using animal models.

PubMed

Watanabe, Kei; Funahashi, Shintaro

2018-01-01

The study of dual-task performance in human subjects has received considerable interest in cognitive neuroscience because it can provide detailed insights into the neural mechanisms underlying higher-order cognitive control. Despite many decades of research, our understanding of the neurobiological basis of dual-task performance is still limited, and some critical questions are still under debate. Recently, behavioral and neurophysiological studies of dual-task performance in animals have begun to provide intriguing evidence regarding how dual-task information is processed in the brain. In this review, we first summarize key evidence in neuroimaging and neuropsychological studies in humans and discuss possible reasons for discrepancies across studies. We then provide a comprehensive review of the literature on dual-task studies in animals and provide a novel working hypothesis that may reconcile the divergent results in human studies toward a unified view of the mechanisms underlying dual-task processing. Finally, we propose possible directions for future dual-task experiments in the framework of comparative cognitive neuroscience. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

The functional neuroanatomy of multitasking: combining dual tasking with a short term memory task.

PubMed

Deprez, Sabine; Vandenbulcke, Mathieu; Peeters, Ron; Emsell, Louise; Amant, Frederic; Sunaert, Stefan

2013-09-01

Insight into the neural architecture of multitasking is crucial when investigating the pathophysiology of multitasking deficits in clinical populations. Presently, little is known about how the brain combines dual-tasking with a concurrent short-term memory task, despite the relevance of this mental operation in daily life and the frequency of complaints related to this process, in disease. In this study we aimed to examine how the brain responds when a memory task is added to dual-tasking. Thirty-three right-handed healthy volunteers (20 females, mean age 39.9 ± 5.8) were examined with functional brain imaging (fMRI). The paradigm consisted of two cross-modal single tasks (a visual and auditory temporal same-different task with short delay), a dual-task combining both single tasks simultaneously and a multi-task condition, combining the dual-task with an additional short-term memory task (temporal same-different visual task with long delay). Dual-tasking compared to both individual visual and auditory single tasks activated a predominantly right-sided fronto-parietal network and the cerebellum. When adding the additional short-term memory task, a larger and more bilateral frontoparietal network was recruited. We found enhanced activity during multitasking in components of the network that were already involved in dual-tasking, suggesting increased working memory demands, as well as recruitment of multitask-specific components including areas that are likely to be involved in online holding of visual stimuli in short-term memory such as occipito-temporal cortex. These results confirm concurrent neural processing of a visual short-term memory task during dual-tasking and provide evidence for an effective fMRI multitasking paradigm. © 2013 Elsevier Ltd. All rights reserved.

Improving posture-motor dual-task with a supraposture-focus strategy in young and elderly adults

PubMed Central

Yu, Shu-Han

2017-01-01

In a postural-suprapostural task, appropriate prioritization is necessary to achieve task goals and maintain postural stability. A “posture-first” principle is typically favored by elderly people in order to secure stance stability, but this comes at the cost of reduced suprapostural performance. Using a postural-suprapostural task with a motor suprapostural goal, this study investigated differences between young and older adults in dual-task cost across varying task prioritization paradigms. Eighteen healthy young (mean age: 24.8 ± 5.2 years) and 18 older (mean age: 68.8 ± 3.7 years) adults executed a designated force-matching task from a stabilometer board using either a stabilometer stance (posture-focus strategy) or force-matching (supraposture-focus strategy) as the primary task. The dual-task effect (DTE: % change in dual-task condition; positive value: dual-task benefit, negative value: dual-task cost) of force-matching error and reaction time (RT), posture error, and approximate entropy (ApEn) of stabilometer movement were measured. When using the supraposture-focus strategy, young adults exhibited larger DTE values in each behavioral parameter than when using the posture-focus strategy. The older adults using the supraposture-focus strategy also attained larger DTE values for posture error, stabilometer movement ApEn, and force-matching error than when using the posture-focus strategy. These results suggest that the supraposture-focus strategy exerted an increased dual-task benefit for posture-motor dual-tasking in both healthy young and elderly adults. The present findings imply that the older adults should make use of the supraposture-focus strategy for fall prevention during dual-task execution. PMID:28151943

Improving posture-motor dual-task with a supraposture-focus strategy in young and elderly adults.

PubMed

Yu, Shu-Han; Huang, Cheng-Ya

2017-01-01

In a postural-suprapostural task, appropriate prioritization is necessary to achieve task goals and maintain postural stability. A "posture-first" principle is typically favored by elderly people in order to secure stance stability, but this comes at the cost of reduced suprapostural performance. Using a postural-suprapostural task with a motor suprapostural goal, this study investigated differences between young and older adults in dual-task cost across varying task prioritization paradigms. Eighteen healthy young (mean age: 24.8 ± 5.2 years) and 18 older (mean age: 68.8 ± 3.7 years) adults executed a designated force-matching task from a stabilometer board using either a stabilometer stance (posture-focus strategy) or force-matching (supraposture-focus strategy) as the primary task. The dual-task effect (DTE: % change in dual-task condition; positive value: dual-task benefit, negative value: dual-task cost) of force-matching error and reaction time (RT), posture error, and approximate entropy (ApEn) of stabilometer movement were measured. When using the supraposture-focus strategy, young adults exhibited larger DTE values in each behavioral parameter than when using the posture-focus strategy. The older adults using the supraposture-focus strategy also attained larger DTE values for posture error, stabilometer movement ApEn, and force-matching error than when using the posture-focus strategy. These results suggest that the supraposture-focus strategy exerted an increased dual-task benefit for posture-motor dual-tasking in both healthy young and elderly adults. The present findings imply that the older adults should make use of the supraposture-focus strategy for fall prevention during dual-task execution.

Investigating Perfect Timesharing: The Relationship between IM-Compatible Tasks and Dual-Task Performance

ERIC Educational Resources Information Center

Halvorson, Kimberly M.; Ebner, Herschel; Hazeltine, Eliot

2013-01-01

Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two…

Dynamic balance during walking adaptability tasks in individuals post-stroke.

PubMed

Vistamehr, Arian; Balasubramanian, Chitralakshmi K; Clark, David J; Neptune, Richard R; Fox, Emily J

2018-06-06

Maintaining dynamic balance during community ambulation is a major challenge post-stroke. Community ambulation requires performance of steady-state level walking as well as tasks that require walking adaptability. Prior studies on balance control post-stroke have mainly focused on steady-state walking, but walking adaptability tasks have received little attention. The purpose of this study was to quantify and compare dynamic balance requirements during common walking adaptability tasks post-stroke and in healthy adults and identify differences in underlying mechanisms used for maintaining dynamic balance. Kinematic data were collected from fifteen individuals with post-stroke hemiparesis during steady-state forward and backward walking, obstacle negotiation, and step-up tasks. In addition, data from ten healthy adults provided the basis for comparison. Dynamic balance was quantified using the peak-to-peak range of whole-body angular-momentum in each anatomical plane during the paretic, nonparetic and healthy control single-leg-stance phase of the gait cycle. To understand differences in some of the key underlying mechanisms for maintaining dynamic balance, foot placement and plantarflexor muscle activation were examined. Individuals post-stroke had significant dynamic balance deficits in the frontal plane across most tasks, particularly during the paretic single-leg-stance. Frontal plane balance deficits were associated with wider paretic foot placement, elevated body center-of-mass, and lower soleus activity. Further, the obstacle negotiation task imposed a higher balance requirement, particularly during the trailing leg single-stance. Thus, improving paretic foot placement and ankle plantarflexor activity, particularly during obstacle negotiation, may be important rehabilitation targets to enhance dynamic balance during post-stroke community ambulation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Does physiotherapy based on the Bobath concept, in conjunction with a task practice, achieve greater improvement in walking ability in people with stroke compared to physiotherapy focused on structured task practice alone?: a pilot randomized controlled trial.

PubMed

Brock, Kim; Haase, Gerlinde; Rothacher, Gerhard; Cotton, Susan

2011-10-01

To compare the short-term effects of two physiotherapy approaches for improving ability to walk in different environments following stroke: (i) interventions based on the Bobath concept, in conjunction with task practice, compared to (ii) structured task practice alone. Randomized controlled trial. Two rehabilitation centres Participants: Twenty-six participants between four and 20 weeks post-stroke, able to walk with supervision indoors. Both groups received six one-hour physiotherapy sessions over a two-week period. One group received physiotherapy based on the Bobath concept, including one hour of structured task practice. The other group received six hours of structured task practice. The primary outcome was an adapted six-minute walk test, incorporating a step, ramp and uneven surface. Secondary measures were gait velocity and the Berg Balance Scale. Measures were assessed before and after the intervention period. Following the intervention, there was no significant difference in improvement between the two groups for the adapted six-minute walk test (89.9 (standard deviation (SD) 73.1) m Bobath versus 41 (40.7) m task practice, P = 0.07). However, walking velocity showed significantly greater increases in the Bobath group (26.2 (SD 17.2) m/min versus 9.9 (SD = 12.9) m/min, P = 0.01). No significant differences between groups were recorded for the Berg Balance Scale (P = 0.2). This pilot study indicates short-term benefit for using interventions based on the Bobath concept for improving walking velocity in people with stroke. A sample size of 32 participants per group is required for a definitive study.

Visual task performance using a monocular see-through head-mounted display (HMD) while walking.

PubMed

Mustonen, Terhi; Berg, Mikko; Kaistinen, Jyrki; Kawai, Takashi; Häkkinen, Jukka

2013-12-01

A monocular see-through head-mounted display (HMD) allows the user to view displayed information while simultaneously interacting with the surrounding environment. This configuration lets people use HMDs while they are moving, such as while walking. However, sharing attention between the display and environment can compromise a person's performance in any ongoing task, and controlling one's gait may add further challenges. In this study, the authors investigated how the requirements of HMD-administered visual tasks altered users' performance while they were walking. Twenty-four university students completed 3 cognitive tasks (high- and low-working memory load, visual vigilance) on an HMD while seated and while simultaneously performing a paced walking task in a controlled environment. The results show that paced walking worsened performance (d', reaction time) in all HMD-administered tasks, but visual vigilance deteriorated more than memory performance. The HMD-administered tasks also worsened walking performance (speed, path overruns) in a manner that varied according to the overall demands of the task. These results suggest that people's ability to process information displayed on an HMD may worsen while they are in motion. Furthermore, the use of an HMD can critically alter a person's natural performance, such as their ability to guide and control their gait. In particular, visual tasks that involve constant monitoring of the HMD should be avoided. These findings highlight the need for careful consideration of the type and difficulty of information that can be presented through HMDs while still letting the user achieve an acceptable overall level of performance in various contexts of use. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Seeing the Errors You Feel Enhances Locomotor Performance but Not Learning.

PubMed

Roemmich, Ryan T; Long, Andrew W; Bastian, Amy J

2016-10-24

In human motor learning, it is thought that the more information we have about our errors, the faster we learn. Here, we show that additional error information can lead to improved motor performance without any concomitant improvement in learning. We studied split-belt treadmill walking that drives people to learn a new gait pattern using sensory prediction errors detected by proprioceptive feedback. When we also provided visual error feedback, participants acquired the new walking pattern far more rapidly and showed accelerated restoration of the normal walking pattern during washout. However, when the visual error feedback was removed during either learning or washout, errors reappeared with performance immediately returning to the level expected based on proprioceptive learning alone. These findings support a model with two mechanisms: a dual-rate adaptation process that learns invariantly from sensory prediction error detected by proprioception and a visual-feedback-dependent process that monitors learning and corrects residual errors but shows no learning itself. We show that our voluntary correction model accurately predicted behavior in multiple situations where visual feedback was used to change acquisition of new walking patterns while the underlying learning was unaffected. The computational and behavioral framework proposed here suggests that parallel learning and error correction systems allow us to rapidly satisfy task demands without necessarily committing to learning, as the relative permanence of learning may be inappropriate or inefficient when facing environments that are liable to change. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults - A Pilot Study.

PubMed

Heinzel, Stephan; Rimpel, Jérôme; Stelzel, Christine; Rapp, Michael A

2017-01-01

Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60-72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality ( p < 0.05) and the auditory modality ( p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination.

Transfer Effects to a Multimodal Dual-Task after Working Memory Training and Associated Neural Correlates in Older Adults – A Pilot Study

PubMed Central

Heinzel, Stephan; Rimpel, Jérôme; Stelzel, Christine; Rapp, Michael A.

2017-01-01

Working memory (WM) performance declines with age. However, several studies have shown that WM training may lead to performance increases not only in the trained task, but also in untrained cognitive transfer tasks. It has been suggested that transfer effects occur if training task and transfer task share specific processing components that are supposedly processed in the same brain areas. In the current study, we investigated whether single-task WM training and training-related alterations in neural activity might support performance in a dual-task setting, thus assessing transfer effects to higher-order control processes in the context of dual-task coordination. A sample of older adults (age 60–72) was assigned to either a training or control group. The training group participated in 12 sessions of an adaptive n-back training. At pre and post-measurement, a multimodal dual-task was performed in all participants to assess transfer effects. This task consisted of two simultaneous delayed match to sample WM tasks using two different stimulus modalities (visual and auditory) that were performed either in isolation (single-task) or in conjunction (dual-task). A subgroup also participated in functional magnetic resonance imaging (fMRI) during the performance of the n-back task before and after training. While no transfer to single-task performance was found, dual-task costs in both the visual modality (p < 0.05) and the auditory modality (p < 0.05) decreased at post-measurement in the training but not in the control group. In the fMRI subgroup of the training participants, neural activity changes in left dorsolateral prefrontal cortex (DLPFC) during one-back predicted post-training auditory dual-task costs, while neural activity changes in right DLPFC during three-back predicted visual dual-task costs. Results might indicate an improvement in central executive processing that could facilitate both WM and dual-task coordination. PMID:28286477

The Influence of a Cognitive Dual Task on the Gait Parameters of Healthy Older Adults: A Systematic Review and Meta-Analysis.

PubMed

Smith, Erin; Cusack, Tara; Cunningham, Caitriona; Blake, Catherine

2017-10-01

This review examines the effect of a dual task on the gait parameters of older adults with a mean gait speed of 1.0 m/s or greater, and the effect of type and complexity of task. A systematic review of Web of Science, PubMed, SCOPUS, Embase, and PsycINFO was performed in July 2016. Twenty-three studies (28 data sets) were reviewed and pooled for meta-analysis. The effect size on seven gait parameters was measured as the raw mean difference between single- and dual-task performance. Gait speed significantly reduced with the addition of a dual task, with increasing complexity showing greater decrements. Cadence, stride time, and measures of gait variability were all negatively affected under the dual-task condition. In older adults, the addition of a dual task significantly reduces gait speed and cadence, with possible implications for the assessment of older people, as the addition of a dual task may expose deficits not observed under single-task assessment.

Persistency and flexibility of complex brain networks underlie dual-task interference.

PubMed

Alavash, Mohsen; Hilgetag, Claus C; Thiel, Christiane M; Gießing, Carsten

2015-09-01

Previous studies on multitasking suggest that performance decline during concurrent task processing arises from interfering brain modules. Here, we used graph-theoretical network analysis to define functional brain modules and relate the modular organization of complex brain networks to behavioral dual-task costs. Based on resting-state and task fMRI we explored two organizational aspects potentially associated with behavioral interference when human subjects performed a visuospatial and speech task simultaneously: the topological overlap between persistent single-task modules, and the flexibility of single-task modules in adaptation to the dual-task condition. Participants showed a significant decline in visuospatial accuracy in the dual-task compared with single visuospatial task. Global analysis of topological similarity between modules revealed that the overlap between single-task modules significantly correlated with the decline in visuospatial accuracy. Subjects with larger overlap between single-task modules showed higher behavioral interference. Furthermore, lower flexible reconfiguration of single-task modules in adaptation to the dual-task condition significantly correlated with larger decline in visuospatial accuracy. Subjects with lower modular flexibility showed higher behavioral interference. At the regional level, higher overlap between single-task modules and less modular flexibility in the somatomotor cortex positively correlated with the decline in visuospatial accuracy. Additionally, higher modular flexibility in cingulate and frontal control areas and lower flexibility in right-lateralized nodes comprising the middle occipital and superior temporal gyri supported dual-tasking. Our results suggest that persistency and flexibility of brain modules are important determinants of dual-task costs. We conclude that efficient dual-tasking benefits from a specific balance between flexibility and rigidity of functional brain modules. © 2015 Wiley Periodicals, Inc.

Age Differences between Children and Young Adults in the Dynamics of Dual-Task Prioritization: Body (Balance) versus Mind (Memory)

ERIC Educational Resources Information Center

Schaefer, Sabine; Krampe, Ralf Th.; Lindenberger, Ulman; Baltes, Paul B.

2008-01-01

Task prioritization can lead to trade-off patterns in dual-task situations. The authors compared dual-task performances in 9- and 11-year-old children and young adults performing a cognitive task and a motor task concurrently. The motor task required balancing on an ankle-disc board. Two cognitive tasks measured working memory and episodic memory…

An investigation of response and stimulus modality transfer effects after dual-task training in younger and older.

PubMed

Lussier, Maxime; Gagnon, Christine; Bherer, Louis

2012-01-01

It has been shown that dual-task training leads to significant improvement in dual-task performance in younger and older adults. However, the extent to which training benefits to untrained tasks requires further investigation. The present study assessed (a) whether dual-task training leads to cross-modality transfer in untrained tasks using new stimuli and/or motor responses modalities, (b) whether transfer effects are related to improved ability to prepare and maintain multiple task-set and/or enhanced response coordination, (c) whether there are age-related differences in transfer effects. Twenty-three younger and 23 older adults were randomly assigned to dual-task training or control conditions. All participants were assessed before and after training on three dual-task transfer conditions; (1) stimulus modality transfer (2) response modality transfer (3) stimulus and response modalities transfer task. Training group showed larger improvement than the control group in the three transfer dual-task conditions, which suggests that training leads to more than specific learning of stimuli/response associations. Attentional costs analyses showed that training led to improved dual-task cost, only in conditions that involved new stimuli or response modalities, but not both. Moreover, training did not lead to a reduced task-set cost in the transfer conditions, which suggests some limitations in transfer effects that can be expected. Overall, the present study supports the notion that cognitive plasticity for attentional control is preserved in late adulthood.

Physical exercise improves strength, balance, mobility, and endurance in people with cognitive impairment and dementia: a systematic review.

PubMed

Lam, Freddy Mh; Huang, Mei-Zhen; Liao, Lin-Rong; Chung, Raymond Ck; Kwok, Timothy Cy; Pang, Marco Yc

2018-01-01

Does physical exercise training improve physical function and quality of life in people with cognitive impairment and dementia? Which training protocols improve physical function and quality of life? How do cognitive impairment and other patient characteristics influence the outcomes of exercise training? Systematic review with meta-analysis of randomised trials. People with mild cognitive impairment or dementia as the primary diagnosis. Physical exercise. Strength, flexibility, gait, balance, mobility, walking endurance, dual-task ability, activities of daily living, quality of life, and falls. Forty-three clinical trials (n=3988) were included. According to the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system, the meta-analyses revealed strong evidence in support of using supervised exercise training to improve the results of 30-second sit-to-stand test (MD 2.1 repetitions, 95% CI 0.3 to 3.9), step length (MD 5cm, 95% CI 2 to 8), Berg Balance Scale (MD 3.6 points, 95% CI 0.3 to 7.0), functional reach (3.9cm, 95% CI 2.2 to 5.5), Timed Up and Go test (-1second, 95% CI -2 to 0), walking speed (0.13m/s, 95% CI 0.03 to 0.24), and 6-minute walk test (50m, 95% CI 18 to 81) in individuals with mild cognitive impairment or dementia. Weak evidence supported the use of exercise in improving flexibility and Barthel Index performance. Weak evidence suggested that non-specific exercise did not improve dual-tasking ability or activity level. Strong evidence indicated that exercise did not improve quality of life in this population. The effect of exercise on falls remained inconclusive. Poorer physical function was a determinant of better response to exercise training, but cognitive performance did not have an impact. People with various levels of cognitive impairment can benefit from supervised multi-modal exercise for about 60minutes a day, 2 to 3days a week to improve physical function. [Lam FMH , Huang MZ, Liao LR, Chung RCK, Kwok TCY, Pang MYC (2018) Physical exercise improves strength, balance, mobility, and endurance in people with cognitive impairment and dementia: a systematic review. Journal of Physiotherapy 64: 4-15]. Copyright © 2017 Australian Physiotherapy Association. Published by Elsevier B.V. All rights reserved.

Association of Dual-Task Gait With Incident Dementia in Mild Cognitive Impairment: Results From the Gait and Brain Study.

PubMed

Montero-Odasso, Manuel M; Sarquis-Adamson, Yanina; Speechley, Mark; Borrie, Michael J; Hachinski, Vladimir C; Wells, Jennie; Riccio, Patricia M; Schapira, Marcelo; Sejdic, Ervin; Camicioli, Richard M; Bartha, Robert; McIlroy, William E; Muir-Hunter, Susan

2017-07-01

Gait performance is affected by neurodegeneration in aging and has the potential to be used as a clinical marker for progression from mild cognitive impairment (MCI) to dementia. A dual-task gait test evaluating the cognitive-motor interface may predict dementia progression in older adults with MCI. To determine whether a dual-task gait test is associated with incident dementia in MCI. The Gait and Brain Study is an ongoing prospective cohort study of community-dwelling older adults that enrolled 112 older adults with MCI. Participants were followed up for 6 years, with biannual visits including neurologic, cognitive, and gait assessments. Data were collected from July 2007 to March 2016. Incident all-cause dementia was the main outcome measure, and single- and dual-task gait velocity and dual-task gait costs were the independent variables. A neuropsychological test battery was used to assess cognition. Gait velocity was recorded under single-task and 3 separate dual-task conditions using an electronic walkway. Dual-task gait cost was defined as the percentage change between single- and dual-task gait velocities: ([single-task gait velocity - dual-task gait velocity]/ single-task gait velocity) × 100. Cox proportional hazard models were used to estimate the association between risk of progression to dementia and the independent variables, adjusted for age, sex, education, comorbidities, and cognition. Among 112 study participants with MCI, mean (SD) age was 76.6 (6.9) years, 55 were women (49.1%), and 27 progressed to dementia (24.1%), with an incidence rate of 121 per 1000 person-years. Slow single-task gait velocity (<0.8 m/second) was not associated with progression to dementia (hazard ratio [HR], 3.41; 95% CI, 0.99-11.71; P = .05)while high dual-task gait cost while counting backward (HR, 3.79; 95% CI, 1.57-9.15; P = .003) and naming animals (HR, 2.41; 95% CI, 1.04-5.59; P = .04) were associated with dementia progression (incidence rate, 155 per 1000 person-years). The models remained robust after adjusting by baseline cognition except for dual-task gait cost when dichotomized. Dual-task gait is associated with progression to dementia in patients with MCI. Dual-task gait testing is easy to administer and may be used by clinicians to decide further biomarker testing, preventive strategies, and follow-up planning in patients with MCI. clinicaltrials.gov: NCT03020381.

The effects of dual tasking on handwriting in patients with Parkinson's disease.

PubMed

Broeder, S; Nackaerts, E; Nieuwboer, A; Smits-Engelsman, B C M; Swinnen, S P; Heremans, E

2014-03-28

Previous studies have shown that patients with Parkinson's disease (PD) experience extensive problems during dual tasking. Up to now, dual-task interference in PD has mainly been investigated in the context of gait research. However, the simultaneous performance of two different tasks is also a prerequisite to efficiently perform many other tasks in daily life, including upper limb tasks. To address this issue, this study investigated the effect of a secondary cognitive task on the performance of handwriting in patients with PD. Eighteen PD patients and 11 age-matched controls performed a writing task involving the production of repetitive loops under single- and dual-task conditions. The secondary task consisted of counting high and low tones during writing. The writing tests were performed with two amplitudes (0.6 and 1.0cm) using a writing tablet. Results showed that dual-task performance was affected in PD patients versus controls. Dual tasking reduced writing amplitude in PD patients, but not in healthy controls (p=0.046). Patients' writing size was mainly reduced during the small-amplitude condition (small amplitude p=0.017; large amplitude p=0.310). This suggests that the control of writing at small amplitudes requires more compensational brain-processing recourses in PD and is as such less automatic than writing at large amplitudes. In addition, there was a larger dual-task effect on the secondary task in PD patients than controls (p=0.025). The writing tests on the writing tablet proved highly correlated to daily life writing as measured by the 'Systematic Screening of Handwriting Difficulties' test (SOS-test) and other manual dexterity tasks, particularly during dual-task conditions. Taken together, these results provide additional insights into the motor control of handwriting and the effects of dual tasking during upper limb movements in patients with PD. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Dual-task performance involving hand dexterity and cognitive tasks and daily functioning in people with schizophrenia: a pilot study.

PubMed

Lin, Keh-chung; Wu, Yi-fang; Chen, I-chen; Tsai, Pei-luen; Wu, Ching-yi; Chen, Chia-ling

2015-01-01

This study investigated separate and concurrent performance on cognitive and hand dexterity tasks and the relationship to daily functioning in 16 people with schizophrenia and 16 healthy control participants. Participants performed the Purdue Pegboard Test and the Serial Seven Subtraction Test under single- and dual-task conditions and completed two daily functioning evaluations. The hand dexterity of all participants declined in the dual-task condition, but the discrepancy between single-task and dual-task hand dexterity was greater in the schizophrenia group than in the control group (p<.03, d>.70, for all). The extent of discrepancy in hand dexterity was negatively correlated with daily functioning in the schizophrenia group (rs=-.3 to -.5, ps=.04-.26). Ability to perform dual tasks may be an indicator of daily functioning in people with schizophrenia. Use of dual-task training may be considered as a therapeutic activity with these clients. Copyright © 2015 by the American Occupational Therapy Association, Inc.

Multitasking During Degraded Speech Recognition in School-Age Children

PubMed Central

Ward, Kristina M.; Brehm, Laurel

2017-01-01

Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children’s multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children’s accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance. Children experienced dual-task costs in the 6- and 4-channel conditions of the primary speech recognition task with decreased accuracy on the visual monitoring task relative to baseline performance. In all conditions, children’s dual-task performance on the visual monitoring task was strongly predicted by their single-task (baseline) performance on the task. Results suggest that children’s proficiency with the secondary task contributes to the magnitude of dual-task costs while multitasking during degraded speech recognition. PMID:28105890

Multitasking During Degraded Speech Recognition in School-Age Children.

PubMed

Grieco-Calub, Tina M; Ward, Kristina M; Brehm, Laurel

2017-01-01

Multitasking requires individuals to allocate their cognitive resources across different tasks. The purpose of the current study was to assess school-age children's multitasking abilities during degraded speech recognition. Children (8 to 12 years old) completed a dual-task paradigm including a sentence recognition (primary) task containing speech that was either unprocessed or noise-band vocoded with 8, 6, or 4 spectral channels and a visual monitoring (secondary) task. Children's accuracy and reaction time on the visual monitoring task was quantified during the dual-task paradigm in each condition of the primary task and compared with single-task performance. Children experienced dual-task costs in the 6- and 4-channel conditions of the primary speech recognition task with decreased accuracy on the visual monitoring task relative to baseline performance. In all conditions, children's dual-task performance on the visual monitoring task was strongly predicted by their single-task (baseline) performance on the task. Results suggest that children's proficiency with the secondary task contributes to the magnitude of dual-task costs while multitasking during degraded speech recognition.

It's how you get there: walking down a virtual alley activates premotor and parietal areas.

PubMed

Wagner, Johanna; Solis-Escalante, Teodoro; Scherer, Reinhold; Neuper, Christa; Müller-Putz, Gernot

2014-01-01

Voluntary drive is crucial for motor learning, therefore we are interested in the role that motor planning plays in gait movements. In this study we examined the impact of an interactive Virtual Environment (VE) feedback task on the EEG patterns during robot assisted walking. We compared walking in the VE modality to two control conditions: walking with a visual attention paradigm, in which visual stimuli were unrelated to the motor task; and walking with mirror feedback, in which participants observed their own movements. Eleven healthy participants were considered. Application of independent component analysis to the EEG revealed three independent component clusters in premotor and parietal areas showing increased activity during walking with the adaptive VE training paradigm compared to the control conditions. During the interactive VE walking task spectral power in frequency ranges 8-12, 15-20, and 23-40 Hz was significantly (p ≤ 0.05) decreased. This power decrease is interpreted as a correlate of an active cortical area. Furthermore activity in the premotor cortex revealed gait cycle related modulations significantly different (p ≤ 0.05) from baseline in the frequency range 23-40 Hz during walking. These modulations were significantly (p ≤ 0.05) reduced depending on gait cycle phases in the interactive VE walking task compared to the control conditions. We demonstrate that premotor and parietal areas show increased activity during walking with the adaptive VE training paradigm, when compared to walking with mirror- and movement unrelated feedback. Previous research has related a premotor-parietal network to motor planning and motor intention. We argue that movement related interactive feedback enhances motor planning and motor intention. We hypothesize that this might improve gait recovery during rehabilitation.

Supertaskers: Profiles in extraordinary multitasking ability.

PubMed

Watson, Jason M; Strayer, David L

2010-08-01

Theory suggests that driving should be impaired for any motorist who is concurrently talking on a cell phone. But is everybody impaired by this dual-task combination? We tested 200 participants in a high-fidelity driving simulator in both single- and dual-task conditions. The dual task involved driving while performing a demanding auditory version of the operation span (OSPAN) task. Whereas the vast majority of participants showed significant performance decrements in dual-task conditions (compared with single-task conditions for either driving or OSPAN tasks), 2.5% of the sample showed absolutely no performance decrements with respect to performing single and dual tasks. In single-task conditions, these "supertaskers" scored in the top quartile on all dependent measures associated with driving and OSPAN tasks, and Monte Carlo simulations indicated that the frequency of supertaskers was significantly greater than chance. These individual differences help to sharpen our theoretical understanding of attention and cognitive control in naturalistic settings.

Brain Activation for Language Dual-Tasking: Listening to Two People Speak at the Same Time and a Change in Network Timing

PubMed Central

Buchweitz, Augusto; Keller, Timothy A.; Meyler, Ann; Just, Marcel Adam

2011-01-01

The study used fMRI to investigate brain activation in participants who were able to listen to and successfully comprehend two people speaking at the same time (dual-tasking). The study identified brain mechanisms associated with high-level, concurrent dual-tasking, as compared to comprehending a single message. Results showed an increase in the functional connectivity among areas of the language network in the dual task. The increase in synchronization of brain activation for dual-tasking was brought about primarily by a change in the timing of left inferior frontal gyrus (LIFG) activation relative to posterior temporal activation, bringing the LIFG activation into closer correspondence with temporal activation. The results show that the change in LIFG timing was greater in participants with lower working memory capacity, and that recruitment of additional activation in the dual-task occurred only in the areas adjacent to the language network that was activated in the single task. The shift in LIFG activation may be a brain marker of how the brain adapts to high-level dual-tasking. PMID:21618666

A systematic review of interventions conducted in clinical or community settings to improve dual-task postural control in older adults.

PubMed

Agmon, Maayan; Belza, Basia; Nguyen, Huong Q; Logsdon, Rebecca G; Kelly, Valerie E

2014-01-01

Injury due to falls is a major problem among older adults. Decrements in dual-task postural control performance (simultaneously performing two tasks, at least one of which requires postural control) have been associated with an increased risk of falling. Evidence-based interventions that can be used in clinical or community settings to improve dual-task postural control may help to reduce this risk. THE AIMS OF THIS SYSTEMATIC REVIEW ARE: 1) to identify clinical or community-based interventions that improved dual-task postural control among older adults; and 2) to identify the key elements of those interventions. Studies were obtained from a search conducted through October 2013 of the following electronic databases: PubMed, CINAHL, PsycINFO, and Web of Science. Randomized and nonrandomized controlled studies examining the effects of interventions aimed at improving dual-task postural control among community-dwelling older adults were selected. All studies were evaluated based on methodological quality. Intervention characteristics including study purpose, study design, and sample size were identified, and effects of dual-task interventions on various postural control and cognitive outcomes were noted. Twenty-two studies fulfilled the selection criteria and were summarized in this review to identify characteristics of successful interventions. The ability to synthesize data was limited by the heterogeneity in participant characteristics, study designs, and outcome measures. Dual-task postural control can be modified by specific training. There was little evidence that single-task training transferred to dual-task postural control performance. Further investigation of dual-task training using standardized outcome measurements is needed.

Stay Focused! The Effects of Internal and External Focus of Attention on Movement Automaticity in Patients with Stroke

PubMed Central

Kal, E. C.; van der Kamp, J.; Houdijk, H.; Groet, E.; van Bennekom, C. A. M.; Scherder, E. J. A.

2015-01-01

Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients’ automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution). Thirty-nine individuals with chronic, unilateral stroke performed a one-leg-stepping task with both legs in single- and dual-task conditions. Attentional focus was manipulated with instructions. Motor performance (movement speed), movement automaticity (fluency of movement), and dual-task performance (dual-task costs) were assessed. The effects of focus on movement speed, single- and dual-task movement fluency, and dual-task costs were analysed with generalized estimating equations. Results showed that, overall, single-task performance was unaffected by focus (p = .341). Regarding movement fluency, no main effects of focus were found in single- or dual-task conditions (p’s ≥ .13). However, focus by leg interactions suggested that an external focus reduced movement fluency of the paretic leg compared to an internal focus (single-task conditions: p = .068; dual-task conditions: p = .084). An external focus also tended to result in inferior dual-task performance (β = -2.38, p = .065). Finally, a near-significant interaction (β = 2.36, p = .055) suggested that dual-task performance was more constrained by patients’ attentional capacity in external focus conditions. We conclude that, compared to an internal focus, an external focus did not result in more automated movements in chronic stroke patients. Contrary to expectations, trends were found for enhanced automaticity with an internal focus. These findings might be due to patients’ strong preference to use an internal focus in daily life. Future work needs to establish the more permanent effects of learning with different attentional foci on re-automating motor control after stroke. PMID:26317437

Electrocortical correlates of human level-ground, slope, and stair walking

PubMed Central

Nakagome, Sho; Zhu, Fangshi; Contreras-Vidal, Jose L.

2017-01-01

This study investigated electrocortical dynamics of human walking across different unconstrained walking conditions (i.e., level ground (LW), ramp ascent (RA), and stair ascent (SA)). Non-invasive active-electrode scalp electroencephalography (EEG) signals were recorded and a systematic EEG processing method was implemented to reduce artifacts. Source localization combined with independent component analysis and k-means clustering revealed the involvement of four clusters in the brain during the walking tasks: Left and Right Occipital Lobe (LOL, ROL), Posterior Parietal Cortex (PPC), and Central Sensorimotor Cortex (SMC). Results showed that the changes of spectral power in the PPC and SMC clusters were associated with the level of motor task demands. Specifically, we observed α and β suppression at the beginning of the gait cycle in both SA and RA walking (relative to LW) in the SMC. Additionally, we observed significant β rebound (synchronization) at the initial swing phase of the gait cycle, which may be indicative of active cortical signaling involved in maintaining the current locomotor state. An increase of low γ band power in this cluster was also found in SA walking. In the PPC, the low γ band power increased with the level of task demands (from LW to RA and SA). Additionally, our results provide evidence that electrocortical amplitude modulations (relative to average gait cycle) are correlated with the level of difficulty in locomotion tasks. Specifically, the modulations in the PPC shifted to higher frequency bands when the subjects walked in RA and SA conditions. Moreover, low γ modulations in the central sensorimotor area were observed in the LW walking and shifted to lower frequency bands in RA and SA walking. These findings extend our understanding of cortical dynamics of human walking at different level of locomotion task demands and reinforces the growing body of literature supporting a shared-control paradigm between spinal and cortical networks during locomotion. PMID:29190704

Balance exercise program reduced falls in people with multiple sclerosis: a single-group, pretest-posttest trial.

PubMed

Nilsagård, Ylva Elisabet; von Koch, Lena Kristina; Nilsson, Malin; Forsberg, Anette Susanne

2014-12-01

To evaluate the effects of a balance exercise program on falls in people with mild to moderate multiple sclerosis (MS). Multicenter, single-blinded, single-group, pretest-posttest trial. Seven rehabilitation units within 5 county councils. Community-dwelling adults with MS (N=32) able to walk 100m but unable to maintain 30-second tandem stance with arms alongside the body. Seven weeks of twice-weekly, physiotherapist-led 60-minute sessions of group-based balance exercise targeting core stability, dual tasking, and sensory strategies (CoDuSe). Primary outcomes: number of prospectively reported falls and proportion of participants classified as fallers during 7 preintervention weeks, intervention period, and 7 postintervention weeks. Secondary outcomes: balance performance on the Berg Balance Scale, Four Square Step Test, sit-to-stand test, timed Up and Go test (alone and with cognitive component), and Functional Gait Assessment Scale; perceived limitations in walking on the 12-item MS Walking Scale; and balance confidence on the Activities-specific Balance Confidence Scale rated 7 weeks before intervention, directly after intervention, and 7 weeks later. Number of falls (166 to 43; P≤.001) and proportion of fallers (17/32 to 10/32; P≤.039) decreased significantly between the preintervention and postintervention periods. Balance performance improved significantly. No significant differences were detected for perceived limitations in walking, balance confidence, the timed Up and Go test, or sit-to-stand test. The CoDuSe program reduced falls and proportion of fallers and improved balance performance in people with mild to moderate MS but did not significantly alter perceived limitations in walking and balance confidence. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

A CAI System for Visually Impaired Children to Improve Abilities of Orientation and Mobility

NASA Astrophysics Data System (ADS)

Yoneda, Takahiro; Kudo, Hiroaki; Minagawa, Hiroki; Ohnishi, Noboru; Matsubara, Shizuya

Some visually impaired children have difficulty in simple locomotion, and need orientation and mobility training. We developed a computer assisted instruction system which assists this training. A user realizes a task given by a tactile map and synthesized speech. The user walks around a room according to the task. The system gives the gap of walk path from its target path via both auditory and tactile feedback after the end of a task. Then the user can understand how well the user walked. We describe the detail of the proposed system and task, and the experimental result with three visually impaired children.

Does dual-task coordination performance decline in later life?

PubMed

Sebastián, María V; Mediavilla, Roberto

2017-05-01

This cross-sectional study examined whether changes occur in people’s capacity to coordinate two simultaneous tasks (dual-task) when transitioning from adulthood to later life. The central executive, Baddeley’s working memory model component, is responsible for this coordination. Contradictory results have been reported regarding the relationship between ageing and dual-task performance; but these seem to be related to methodological issues that have been addressed in this study. Nine hundred and seventy-two participants, aged between 35 and 90 years old, volunteered to carry out a verbal digit span task, followed by single and concurrent (dual-task) tests: first, a box crossing task, then, the digit recall task in relation to their memory span, and finally, both these tests simultaneously. We found no difference in people’s capacity to coordinate their attention when doing two tasks in adulthood or healthy later life, including those in the oldest age groups. Furthermore, gender and educational level were not related to dual-task performance. The results support the normal functioning of the central executive in very old people. These data contrast with research with patients suffering from different types of dementia, which show a decrease in their dual-task performance.

Executive function and falls in older adults: new findings from a five-year prospective study link fall risk to cognition.

PubMed

Mirelman, Anat; Herman, Talia; Brozgol, Marina; Dorfman, Moran; Sprecher, Elliot; Schweiger, Avraham; Giladi, Nir; Hausdorff, Jeffrey M

2012-01-01

Recent findings suggest that executive function (EF) plays a critical role in the regulation of gait in older adults, especially under complex and challenging conditions, and that EF deficits may, therefore, contribute to fall risk. The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up. Secondary objectives were to assess whether single and dual task walking abilities, an alternative window into EF, were associated with fall risk. We longitudinally followed 256 community-living older adults (age: 76.4±4.5 yrs; 61% women) who were dementia free and had good mobility upon entrance into the study. At baseline, a computerized cognitive battery generated an index of EF, attention, a closely related construct, and other cognitive domains. Gait was assessed during single and dual task conditions. Falls data were collected prospectively using monthly calendars. Negative binomial regression quantified risk ratios (RR). After adjusting for age, gender and the number of falls in the year prior to the study, only the EF index (RR: .85; CI: .74-.98, p = .021), the attention index (RR: .84; CI: .75-.94, p = .002) and dual tasking gait variability (RR: 1.11; CI: 1.01-1.23; p = .027) were associated with future fall risk. Other cognitive function measures were not related to falls. Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up (p<0.02). These findings demonstrate that among community-living older adults, the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier. The present results link falls among older adults to cognition, indicating that screening EF will likely enhance fall risk assessment, and that treatment of EF may reduce fall risk.

Behavioral Assessment of Listening Effort Using a Dual-Task Paradigm.

PubMed

Gagné, Jean-Pierre; Besser, Jana; Lemke, Ulrike

2017-01-01

Published investigations ( n = 29) in which a dual-task experimental paradigm was employed to measure listening effort during speech understanding in younger and older adults were reviewed. A summary of the main findings reported in the articles is provided with respect to the participants' age-group and hearing status. Effects of different signal characteristics, such as the test modality, on dual-task outcomes are evaluated, and associations with cognitive abilities and self-report measures of listening effort are described. Then, several procedural issues associated with the use of dual-task experiment paradigms are discussed. Finally, some issues that warrant future research are addressed. The review revealed large variability in the dual-task experimental paradigms that have been used to measure the listening effort expended during speech understanding. The differences in experimental procedures used across studies make it difficult to draw firm conclusions concerning the optimal choice of dual-task paradigm or the sensitivity of specific paradigms to different types of experimental manipulations. In general, the analysis confirmed that dual-task paradigms have been used successfully to measure differences in effort under different experimental conditions, in both younger and older adults. Several research questions that warrant further investigation in order to better understand and characterize the intricacies of dual-task paradigms were identified.

Behavioral Assessment of Listening Effort Using a Dual-Task Paradigm

PubMed Central

Besser, Jana; Lemke, Ulrike

2017-01-01

Published investigations (n = 29) in which a dual-task experimental paradigm was employed to measure listening effort during speech understanding in younger and older adults were reviewed. A summary of the main findings reported in the articles is provided with respect to the participants’ age-group and hearing status. Effects of different signal characteristics, such as the test modality, on dual-task outcomes are evaluated, and associations with cognitive abilities and self-report measures of listening effort are described. Then, several procedural issues associated with the use of dual-task experiment paradigms are discussed. Finally, some issues that warrant future research are addressed. The review revealed large variability in the dual-task experimental paradigms that have been used to measure the listening effort expended during speech understanding. The differences in experimental procedures used across studies make it difficult to draw firm conclusions concerning the optimal choice of dual-task paradigm or the sensitivity of specific paradigms to different types of experimental manipulations. In general, the analysis confirmed that dual-task paradigms have been used successfully to measure differences in effort under different experimental conditions, in both younger and older adults. Several research questions that warrant further investigation in order to better understand and characterize the intricacies of dual-task paradigms were identified. PMID:28091178

A systematic review of interventions conducted in clinical or community settings to improve dual-task postural control in older adults

PubMed Central

Agmon, Maayan; Belza, Basia; Nguyen, Huong Q; Logsdon, Rebecca G; Kelly, Valerie E

2014-01-01

Background Injury due to falls is a major problem among older adults. Decrements in dual-task postural control performance (simultaneously performing two tasks, at least one of which requires postural control) have been associated with an increased risk of falling. Evidence-based interventions that can be used in clinical or community settings to improve dual-task postural control may help to reduce this risk. Purpose The aims of this systematic review are: 1) to identify clinical or community-based interventions that improved dual-task postural control among older adults; and 2) to identify the key elements of those interventions. Data sources Studies were obtained from a search conducted through October 2013 of the following electronic databases: PubMed, CINAHL, PsycINFO, and Web of Science. Study selection Randomized and nonrandomized controlled studies examining the effects of interventions aimed at improving dual-task postural control among community-dwelling older adults were selected. Data extraction All studies were evaluated based on methodological quality. Intervention characteristics including study purpose, study design, and sample size were identified, and effects of dual-task interventions on various postural control and cognitive outcomes were noted. Data synthesis Twenty-two studies fulfilled the selection criteria and were summarized in this review to identify characteristics of successful interventions. Limitations The ability to synthesize data was limited by the heterogeneity in participant characteristics, study designs, and outcome measures. Conclusion Dual-task postural control can be modified by specific training. There was little evidence that single-task training transferred to dual-task postural control performance. Further investigation of dual-task training using standardized outcome measurements is needed. PMID:24741296

Improving Dual-Task Control With a Posture-Second Strategy in Early-Stage Parkinson Disease.

PubMed

Huang, Cheng-Ya; Chen, Yu-An; Hwang, Ing-Shiou; Wu, Ruey-Meei

2018-03-31

To examine the task prioritization effects on postural-suprapostural dual-task performance in patients with early-stage Parkinson disease (PD) without clinically observed postural symptoms. Cross-sectional study. Participants performed a force-matching task while standing on a mobile platform, and were instructed to focus their attention on either the postural task (posture-first strategy) or the force-matching task (posture-second strategy). University research laboratory. Individuals (N=16) with early-stage PD who had no clinically observed postural symptoms. Not applicable. Dual-task change (DTC; percent change between single-task and dual-task performance) of posture error, posture approximate entropy (ApEn), force error, and reaction time (RT). Positive DTC values indicate higher postural error, posture ApEn, force error, and force RT during dual-task conditions compared with single-task conditions. Compared with the posture-first strategy, the posture-second strategy was associated with smaller DTC of posture error and force error, and greater DTC of posture ApEn. In contrast, greater DTC of force RT was observed under the posture-second strategy. Contrary to typical recommendations, our results suggest that the posture-second strategy may be an effective dual-task strategy in patients with early-stage PD who have no clinically observed postural symptoms in order to reduce the negative effect of dual tasking on performance and facilitate postural automaticity. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Post-traumatic stress disorder is associated with limited executive resources in a working memory task

PubMed Central

Honzel, Nikki; Justus, Timothy; Swick, Diane

2015-01-01

Patients with post-traumatic stress disorder (PTSD) can show declines in working memory. A dual-task design was used to determine if these impairments are linked to executive control limitations. Participants performed a Sternberg memory task with either one or four letters. In the dual-task condition, the maintenance period was filled with an arrow flanker task. PTSD patients were less accurate on the working memory task than controls, especially in the dual-task condition. In the single-task condition, both groups showed similar patterns of brain potentials from 300–500 ms when discriminating old and new probes. However, when taxed with an additional task, the event-related potentials (ERPs) of the PTSD group no longer differentiated old and new probes. In contrast, interference resolution processes in both the single- and dual-task conditions of the flanker were intact. The lack of differentiation in the ERPs reflects impaired working memory performance under more difficult dual-task conditions. Exacerbated difficulty in performing a working memory task with concurrent task demands suggests a specific limitation in executive control resources in PTSD. PMID:24165904

Brain activation for language dual-tasking: listening to two people speak at the same time and a change in network timing.

PubMed

Buchweitz, Augusto; Keller, Timothy A; Meyler, Ann; Just, Marcel Adam

2012-08-01

The study used fMRI to investigate brain activation in participants who were able to listen to and successfully comprehend two people speaking at the same time (dual-tasking). The study identified brain mechanisms associated with high-level, concurrent dual-tasking, as compared with comprehending a single message. Results showed an increase in the functional connectivity among areas of the language network in the dual task. The increase in synchronization of brain activation for dual-tasking was brought about primarily by a change in the timing of left inferior frontal gyrus (LIFG) activation relative to posterior temporal activation, bringing the LIFG activation into closer correspondence with temporal activation. The results show that the change in LIFG timing was greater in participants with lower working memory capacity, and that recruitment of additional activation in the dual-task occurred only in the areas adjacent to the language network that was activated in the single task. The shift in LIFG activation may be a brain marker of how the brain adapts to high-level dual-tasking. Copyright © 2011 Wiley Periodicals, Inc.

Implicit and Explicit Knowledge Both Improve Dual Task Performance in a Continuous Pursuit Tracking Task.

PubMed

Ewolds, Harald E; Bröker, Laura; de Oliveira, Rita F; Raab, Markus; Künzell, Stefan

2017-01-01

The goal of this study was to investigate the effect of predictability on dual-task performance in a continuous tracking task. Participants practiced either informed (explicit group) or uninformed (implicit group) about a repeated segment in the curves they had to track. In Experiment 1 participants practices the tracking task only, dual-task performance was assessed after by combining the tracking task with an auditory reaction time task. Results showed both groups learned equally well and tracking performance on a predictable segment in the dual-task condition was better than on random segments. However, reaction times did not benefit from a predictable tracking segment. To investigate the effect of learning under dual-task situation participants in Experiment 2 practiced the tracking task while simultaneously performing the auditory reaction time task. No learning of the repeated segment could be demonstrated for either group during the training blocks, in contrast to the test-block and retention test, where participants performed better on the repeated segment in both dual-task and single-task conditions. Only the explicit group improved from test-block to retention test. As in Experiment 1, reaction times while tracking a predictable segment were no better than reaction times while tracking a random segment. We concluded that predictability has a positive effect only on the predictable task itself possibly because of a task-shielding mechanism. For dual-task training there seems to be an initial negative effect of explicit instructions, possibly because of fatigue, but the advantage of explicit instructions was demonstrated in a retention test. This might be due to the explicit memory system informing or aiding the implicit memory system.

Implicit and Explicit Knowledge Both Improve Dual Task Performance in a Continuous Pursuit Tracking Task

PubMed Central

Ewolds, Harald E.; Bröker, Laura; de Oliveira, Rita F.; Raab, Markus; Künzell, Stefan

2017-01-01

The goal of this study was to investigate the effect of predictability on dual-task performance in a continuous tracking task. Participants practiced either informed (explicit group) or uninformed (implicit group) about a repeated segment in the curves they had to track. In Experiment 1 participants practices the tracking task only, dual-task performance was assessed after by combining the tracking task with an auditory reaction time task. Results showed both groups learned equally well and tracking performance on a predictable segment in the dual-task condition was better than on random segments. However, reaction times did not benefit from a predictable tracking segment. To investigate the effect of learning under dual-task situation participants in Experiment 2 practiced the tracking task while simultaneously performing the auditory reaction time task. No learning of the repeated segment could be demonstrated for either group during the training blocks, in contrast to the test-block and retention test, where participants performed better on the repeated segment in both dual-task and single-task conditions. Only the explicit group improved from test-block to retention test. As in Experiment 1, reaction times while tracking a predictable segment were no better than reaction times while tracking a random segment. We concluded that predictability has a positive effect only on the predictable task itself possibly because of a task-shielding mechanism. For dual-task training there seems to be an initial negative effect of explicit instructions, possibly because of fatigue, but the advantage of explicit instructions was demonstrated in a retention test. This might be due to the explicit memory system informing or aiding the implicit memory system. PMID:29312083

Modular control of varied locomotor tasks in children with incomplete spinal cord injuries

PubMed Central

Tester, Nicole J.; Kautz, Steven A.; Howland, Dena R.; Clark, David J.; Garvan, Cyndi; Behrman, Andrea L.

2013-01-01

A module is a functional unit of the nervous system that specifies functionally relevant patterns of muscle activation. In adults, four to five modules account for muscle activation during walking. Neurological injury alters modular control and is associated with walking impairments. The effect of neurological injury on modular control in children is unknown and may differ from adults due to their immature and developing nervous systems. We examined modular control of locomotor tasks in children with incomplete spinal cord injuries (ISCIs) and control children. Five controls (8.6 ± 2.7 yr of age) and five children with ISCIs (8.6 ± 3.7 yr of age performed treadmill walking, overground walking, pedaling, supine lower extremity flexion/extension, stair climbing, and crawling. Electromyograms (EMGs) were recorded in bilateral leg muscles. Nonnegative matrix factorization was applied, and the minimum number of modules required to achieve 90% of the “variance accounted for” (VAF) was calculated. On average, 3.5 modules explained muscle activation in the controls, whereas 2.4 modules were required in the children with ISCIs. To determine if control is similar across tasks, the module weightings identified from treadmill walking were used to reconstruct the EMGs from each of the other tasks. This resulted in VAF values exceeding 86% for each child and each locomotor task. Our results suggest that 1) modularity is constrained in children with ISCIs and 2) for each child, similar neural control mechanisms are used across locomotor tasks. These findings suggest that interventions that activate the neuromuscular system to enhance walking also may influence the control of other locomotor tasks. PMID:23761702

Effects of transcranial direct current stimulation (tDCS) on multiscale complexity of dual-task postural control in older adults.

PubMed

Zhou, Diange; Zhou, Junhong; Chen, Hu; Manor, Brad; Lin, Jianhao; Zhang, Jue

2015-08-01

Transcranial direct current stimulation (tDCS) targeting the prefrontal cortex reduces the size and speed of standing postural sway in younger adults, particularly when performing a cognitive dual task. Here, we hypothesized that tDCS would alter the complex dynamics of postural sway as quantified by multiscale entropy (MSE). Twenty healthy older adults completed two study visits. Center-of-pressure (COP) fluctuations were recorded during single-task (i.e., quiet standing) and dual-task (i.e., standing while performing serial subtractions) conditions, both before and after a 20-min session of real or sham tDCS. MSE was used to estimate COP complexity within each condition. The percentage change in complexity from single- to dual-task conditions (i.e., dual-task cost) was also calculated. Before tDCS, COP complexity was lower (p = 0.04) in the dual-task condition as compared to the single-task condition. Neither real nor sham tDCS altered complexity in the single-task condition. As compared to sham tDCS, real tDCS increased complexity in the dual-task condition (p = 0.02) and induced a trend toward improved serial subtraction performance (p = 0.09). Moreover, those subjects with lower dual-task COP complexity at baseline exhibited greater percentage increases in complexity following real tDCS (R = -0.39, p = 0.05). Real tDCS also reduced the dual-task cost to complexity (p = 0.02), while sham stimulation had no effect. A single session of tDCS targeting the prefrontal cortex increased standing postural sway complexity with concurrent non-postural cognitive task. This form of noninvasive brain stimulation may be a safe strategy to acutely improve postural control by enhancing the system's capacity to adapt to stressors.

Poorer divided attention in children born very preterm can be explained by difficulty with each component task, not the executive requirement to dual-task.

PubMed

Delane, Louise; Campbell, Catherine; Bayliss, Donna M; Reid, Corinne; Stephens, Amelia; French, Noel; Anderson, Mike

2017-07-01

Children born very preterm (VP, ≤ 32 weeks) exhibit poor performance on tasks of executive functioning. However, it is largely unknown whether this reflects the cumulative impact of non-executive deficits or a separable impairment in executive-level abilities. A dual-task paradigm was used in the current study to differentiate the executive processes involved in performing two simple attention tasks simultaneously. The executive-level contribution to performance was indexed by the within-subject cost incurred to single-task performance under dual-task conditions, termed dual-task cost. The participants included 77 VP children (mean age: 7.17 years) and 74 peer controls (mean age: 7.16 years) who completed Sky Search (selective attention), Score (sustained attention) and Sky Search DT (divided attention) from the Test of Everyday Attention for Children. The divided-attention task requires the simultaneous performance of the selective- and sustained-attention tasks. The VP group exhibited poorer performance on the selective- and divided-attention tasks, and showed a strong trend toward poorer performance on the sustained-attention task. However, there were no significant group differences in dual-task cost. These results suggest a cumulative impact of vulnerable lower-level cognitive processes on dual-tasking or divided attention in VP children, and fail to support the hypothesis that VP children show a separable impairment in executive-level abilities.

Effects of age and auditory and visual dual tasks on closed-road driving performance.

PubMed

Chaparro, Alex; Wood, Joanne M; Carberry, Trent

2005-08-01

This study investigated how driving performance of young and old participants is affected by visual and auditory secondary tasks on a closed driving course. Twenty-eight participants comprising two age groups (younger, mean age = 27.3 years; older, mean age = 69.2 years) drove around a 5.1-km closed-road circuit under both single and dual task conditions. Measures of driving performance included detection and identification of road signs, detection and avoidance of large low-contrast road hazards, gap judgment, lane keeping, and time to complete the course. The dual task required participants to verbally report the sums of pairs of single-digit numbers presented through either a computer speaker (auditorily) or a dashboard-mounted monitor (visually) while driving. Participants also completed a vision and cognitive screening battery, including LogMAR visual acuity, Pelli-Robson letter contrast sensitivity, the Trails test, and the Digit Symbol Substitution (DSS) test. Drivers reported significantly fewer signs, hit more road hazards, misjudged more gaps, and increased their time to complete the course under the dual task (visual and auditory) conditions compared with the single task condition. The older participants also reported significantly fewer road signs and drove significantly more slowly than the younger participants, and this was exacerbated for the visual dual task condition. The results of the regression analysis revealed that cognitive aging (measured by the DSS and Trails test) rather than chronologic age was a better predictor of the declines seen in driving performance under dual task conditions. An overall z score was calculated, which took into account both driving and the secondary task (summing) performance under the two dual task conditions. Performance was significantly worse for the auditory dual task compared with the visual dual task, and the older participants performed significantly worse than the young subjects. These findings demonstrate that multitasking had a significant detrimental impact on driving performance and that cognitive aging was the best predictor of the declines seen in driving performance under dual task conditions. These results have implications for use of mobile phones or in-vehicle navigational devices while driving, especially for older adults.

Stopping while Going! Response Inhibition Does Not Suffer Dual-Task Interference

ERIC Educational Resources Information Center

Yamaguchi, Motonori; Logan, Gordon D.; Bissett, Patrick G.

2012-01-01

Although dual-task interference is ubiquitous in a variety of task domains, stop-signal studies suggest that response inhibition is not subject to such interference. Nevertheless, no study has directly examined stop-signal performance in a dual-task setting. In two experiments, stop-signal performance was examined in a psychological refractory…

Musical training, bilingualism, and executive function: a closer look at task switching and dual-task performance.

PubMed

Moradzadeh, Linda; Blumenthal, Galit; Wiseheart, Melody

2015-07-01

This study investigated whether musical training and bilingualism are associated with enhancements in specific components of executive function, namely, task switching and dual-task performance. Participants (n = 153) belonging to one of four groups (monolingual musician, bilingual musician, bilingual non-musician, or monolingual non-musician) were matched on age and socioeconomic status and administered task switching and dual-task paradigms. Results demonstrated reduced global and local switch costs in musicians compared with non-musicians, suggesting that musical training can contribute to increased efficiency in the ability to shift flexibly between mental sets. On dual-task performance, musicians also outperformed non-musicians. There was neither a cognitive advantage for bilinguals relative to monolinguals, nor an interaction between music and language to suggest additive effects of both types of experience. These findings demonstrate that long-term musical training is associated with improvements in task switching and dual-task performance. Copyright © 2014 Cognitive Science Society, Inc.

The attentional demands of ambulating with an assistive device in older adults with Alzheimer's disease.

PubMed

Muir-Hunter, S W; Montero-Odasso, M

2017-05-01

Ambulation with a mobility aid is a unique real-life situation of multi-tasking. These simultaneous motor tasks place increased demands on executive function in healthy young and older adults, but the demands have not been evaluated in people with Alzheimer's disease (AD). Mobility problems are common among adults with AD, leading to provision of a mobility aid to optimize independent activity. The study objectives were: (i) to determine the dual-task cost (DTC) associated with the use of a mobility aid in straight and complex path walking, and (ii) to evaluate the association between executive function and ambulation with a mobility aid in older adults with AD and age-sex matched cognitively normal controls. Fourteen people (mean age±SD, 72.6±9.9years) with a diagnosis of probable AD (MMSE range 12-25) and controls (mean age±SD, 72.9±9.5) walked at a self-selected pace and using a 4-wheeled walker in a 6m straight path and a Figure of 8 Test. Ambulation with the walker in a straight path produced a low DTC that was not different between the groups. Ambulation with the 4-wheeled walker in the complex path produced a significantly different DTC in the group with AD at -38.1±23.5% compared to -19.7±21.4% (p=0.041). Lower scores on executive function were associated with longer times across test conditions. Ambulation with a 4-wheeled walker, in particular maneuvering around obstacles, requires greater attentional costs in dementia. Future research should explore the timing for safely introducing mobility aids in AD and the role of improving executive function. Copyright © 2017 Elsevier B.V. All rights reserved.

Gait assessment in mild cognitive impairment and Alzheimer's disease: the effect of dual-task challenges across the cognitive spectrum.

PubMed

Muir, Susan W; Speechley, Mark; Wells, Jennie; Borrie, Michael; Gopaul, Karen; Montero-Odasso, Manuel

2012-01-01

Gait impairment is a prominent falls risk factor and a prevalent feature among older adults with cognitive impairment. However, there is a lack of comparative studies on gait performance and fall risk covering the continuum from normal cognition through mild cognitive impairment (MCI) to Alzheimer's disease (AD). We evaluated gait performance and the response to dual-task challenges in older adults with AD, MCI and normal cognition without a history of falls. We hypothesized that, in older people without history of falls, gait performance will deteriorate across the cognitive spectrum with changes being more evident under dual-tasking. Gait was assessed using an electronic walkway under single and three dual-tasks conditions. Gait velocity and stride time variability were not significantly different between the three groups under the single-task condition. By contrast, significant differences of decreasing velocity (p<0.0001), increasing stride time (p=0.0057) and increasing stride time variability (p=0.0037) were found under dual-task testing for people with MCI and AD. Less automatic and more complex dual-task tests, such as naming animals and serial subtraction by sevens from 100, created the greatest deterioration of gait performance. Gait changes under dual-tasking for the MCI and AD groups were statistically different from the cognitively normal controls. Dual-task assessment exposed gait impairments not obvious under a single-task test condition and may facilitate falls risk identification in cognitively impaired persons without a history of falls. Copyright © 2011 Elsevier B.V. All rights reserved.

[Features of dual--postural and calculation--task performance in patients with consequences of traumatic brain injury].

PubMed

Zharikova, A V; Zhavoronkova, L A; Maksakova, O A; Kuptsova, S V

2012-01-01

Dual tasks with voluntary postural control and calculation have been done by 14 patients (25.7 +/- 4.7 yo.) after traumatic brain injury and 40 healthy volunteers (29.8 +/- 2.5 y.o.). Complex clinical (MMSE, FIM, MPAI-3 and Berg scales) and stabilographic evaluation has been performed. According to clinical evaluation 8 patients were included into group 1 with less severe functional deficit and 6 patients formed group 2 with more severe deficit. Parameters of motor and especially cognitive sub-tasks in patients were lower than in healthy subjects in both separate and dual tasks. In group 2 these parameters were lower than in group 1. Certain types of dual task where the quality of sub-tasks, especially of the motor-one increased in healthy subjects and patients of the first group were revealed. The complex of stabilographic parameters which could be used for estimation of quality of sub-tasks performance has been revealed. Dual tasks could be an additional method of evaluation of patients' adaptive possibilities and certain type of dual task could become a promising approach to recovery at late period of rehabilitation.

Relationships Between Knee Extension Moments During Weighted and Unweighted Gait and Strength Measures That Predict Knee Moments After ACL Reconstruction.

PubMed

Hartigan, Erin; Aucoin, Jennifer; Carlson, Rita; Klieber-Kusak, Melanie; Murray, Thomas; Shaw, Bernadette; Lawrence, Michael

Weighted gait increases internal knee extension moment impulses (KEMI) in the anterior cruciate ligament-reconstructed (ACLR) limb; however, limb differences persist. (1) KEMI during normal gait will influence KEMI during weighted gait and (2) peak knee extension (PKE) torque and time to reach PKE torque will predict KEMI during gait tasks. Descriptive laboratory study. Twenty-four women and 14 men completed 3 gait tasks (unweighted, vest, sled) and strength testing after discharge from rehabilitation and clearance to return to sports. KEMI were calculated during the first 25% of stance. PKE torque and time to reach PKE torque were obtained using a dynamometer. Data on the ACLR limb and symmetry indices (SIs) were analyzed for each sex. Women presented with asymmetrical PKE torques and KEMI across tasks. There were three correlations noted for KEMI: between the walk and vest, walk and sled, and vest and sled tasks. Slower time to PKE torque predicted limb asymmetries across tasks and KEMI in the ACLR limb during the sled task. Men presented with asymmetrical PKE torques and KEMI during the sled task. There was a correlation noted for KEMI between walk and vest tasks only. During the sled task, ACLR limb time to PKE torque predicted KEMI in the ACLR limb and PKE torque SI predicted KEMI SI. Women use asymmetrical KEMI profiles during all gait tasks, and those with worse KEMI during walking have worse KEMI during weighted gait. Men have asymmetrical KEMI when sled towing, and these KEMIs do not correlate with KEMI during walking or vest tasks. PKE torque deficits persist when attempting to return to sports. Only men use gains in PKE torque to improve KEMI profiles. Although quicker PKE torque generation will increase KEMI in women, normalization of KEMI profiles will not occur by increasing rate of force development only. Gait retraining is recommended to correct asymmetrical KEMI profiles used across gait tasks in women.

The neural architecture of age-related dual-task interferences.

PubMed

Chmielewski, Witold X; Yildiz, Ali; Beste, Christian

2014-01-01

In daily life elderly adults exhibit deficits when dual-tasking is involved. So far these deficits have been verified on a behavioral level in dual-tasking. Yet, the neuronal architecture of these deficits in aging still remains to be explored especially when late-middle aged individuals around 60 years of age are concerned. Neuroimaging studies in young participants concerning dual-tasking were, among others, related to activity in middle frontal (MFG) and superior frontal gyrus (SFG) and the anterior insula (AI). According to the frontal lobe hypothesis of aging, alterations in these frontal regions (i.e., SFG and MFG) might be responsible for cognitive deficits. We measured brain activity using fMRI, while examining age-dependent variations in dual-tasking by utilizing the PRP (psychological refractory period) test. Behavioral data showed an increasing PRP effect in late-middle aged adults. The results suggest the age-related deteriorated performance in dual-tasking, especially in conditions of risen complexity. These effects are related to changes in networks involving the AI, the SFG and the MFG. The results suggest that different cognitive subprocesses are affected that mediate the observed dual-tasking problems in late-middle aged individuals.

The development of children's knowledge of attention and resource allocation in single and dual tasks.

PubMed

Dossett, D; Burns, B

2000-06-01

Developmental changes in kindergarten, 1st-, and 4th-grade children's knowledge about the variables that affect attention sharing and resource allocation were examined. Findings from the 2 experiments showed that kindergartners understood that person and strategy variables affect performance in attention-sharing tasks. However, knowledge of how task variables affect performance was not evident to them and was inconsistent for 1st and 4th graders. Children's knowledge about resource allocation revealed a different pattern and varied according to the dissimilarity of task demands in the attention-sharing task. In Experiment 1, in which the dual attention tasks were similar (i.e., visual detection), kindergarten and 1st-grade children did not differentiate performance in single and dual tasks. Fourth graders demonstrated knowledge that performance on a single task would be better than performance on the dual tasks for only 2 of the variables examined. In Experiment 2, in which the dual attention tasks were dissimilar (i.e., visual and auditory detection), kindergarten and 1st-grade children demonstrated knowledge that performance in the single task would be better than in the dual tasks for 1 of the task variables examined. However, 4th-grade children consistently gave higher ratings for performance on the single than on the dual attention tasks for all variables examined. These findings (a) underscore that children's meta-attention is not unitary and (b) demonstrate that children's knowledge about variables affecting attention sharing and resource allocation have different developmental pathways. Results show that knowledge about attention sharing and about the factors that influence the control of attention develops slowly and undergoes reorganization in middle childhood.

The transition to increased automaticity during finger sequence learning in adult males who stutter.

PubMed

Smits-Bandstra, Sarah; De Nil, Luc; Rochon, Elizabeth

2006-01-01

The present study compared the automaticity levels of persons who stutter (PWS) and persons who do not stutter (PNS) on a practiced finger sequencing task under dual task conditions. Automaticity was defined as the amount of attention required for task performance. Twelve PWS and 12 control subjects practiced finger tapping sequences under single and then dual task conditions. Control subjects performed the sequencing task significantly faster and less variably under single versus dual task conditions while PWS' performance was consistently slow and variable (comparable to the dual task performance of control subjects) under both conditions. Control subjects were significantly more accurate on a colour recognition distracter task than PWS under dual task conditions. These results suggested that control subjects transitioned to quick, accurate and increasingly automatic performance on the sequencing task after practice, while PWS did not. Because most stuttering treatment programs for adults include practice and automatization of new motor speech skills, findings of this finger sequencing study and future studies of speech sequence learning may have important implications for how to maximize stuttering treatment effectiveness. As a result of this activity, the participant will be able to: (1) Define automaticity and explain the importance of dual task paradigms to investigate automaticity; (2) Relate the proposed relationship between motor learning and automaticity as stated by the authors; (3) Summarize the reviewed literature concerning the performance of PWS on dual tasks; and (4) Explain why the ability to transition to automaticity during motor learning may have important clinical implications for stuttering treatment effectiveness.

Kinematic evaluation of virtual walking trajectories.

PubMed

Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

2013-04-01

Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

Effect of Tai Chi Training on Dual-Tasking Performance That Involves Stepping Down among Stroke Survivors: A Pilot Study.

PubMed

Chan, Wing-Nga; Tsang, William Wai-Nam

2017-01-01

Descending stairs demands attention and neuromuscular control, especially with dual-tasking. Studies have demonstrated that stroke often degrades a survivor's ability to descend stairs. Tai Chi has been shown to improve dual-tasking performance of healthy older adults, but no such study has been conducted in stroke survivors. This study investigated the effect of Tai Chi training on dual-tasking performance that involved stepping down and compared it with that of conventional exercise among stroke survivors. Subjects were randomized into Tai Chi ( n = 9), conventional exercise ( n = 8), and control ( n = 9) groups. Those in the former two groups received 12-week training. Assessments included auditory Stroop test, stepping down test, and dual-tasking test involving both simultaneously. They were evaluated before training (time-1), after training (time-2), and one month after training (time-3). Tai Chi group showed significant improvement in the auditory Stroop test from time-1 to time-3 and the performance was significantly better than that of the conventional exercise group in time-3. No significant effect was found in the stepping down task or dual-tasking in the control group. These results suggest a beneficial effect of Tai Chi training on cognition among stroke survivors without compromising physical task performance in dual-tasking. The effect was better than the conventional exercise group. Nevertheless, further research with a larger sample is warranted.

Specific smartphone usage and cognitive performance affect gait characteristics during free-living and treadmill walking.

PubMed

Niederer, Daniel; Bumann, Anke; Mühlhauser, Yvonne; Schmitt, Mareike; Wess, Katja; Engeroff, Tobias; Wilke, Jan; Vogt, Lutz; Banzer, Winfried

2018-05-01

Mobile phone tasks like texting, typing, and dialling during walking are known to impact gait characteristics. Beyond that, the effects of performing smartphone-typical actions like researching and taking self-portraits (selfie) on gait have not been investigated yet. We aimed to investigate the effects of smartphone usage on relevant gait characteristics and to reveal potential association of basic cognitive and walking plus smartphone dual-task abilities. Our cross-sectional, cross-over study on physically active, healthy participants was performed on two days, interrupted by a 24-h washout in between. Assessments were: 1) Cognitive testing battery consisting of the trail making test (TMT A and B) and the Stroop test 2) Treadmill walking under five smartphone usage conditions: no use (control condition), reading, dialling, internet searching and taking a selfie in randomized order. Kinematic and kinetic gait characteristics were assessed to estimate conditions influence. In our sample of 36 adults (24.6 ± 1 years, 23 female, 13 male), ANCOVAs followed by post-hoc t-tests revealed that smartphone usage impaired all tested gait characteristics: gait speed (decrease, all conditions): F = 54.7, p < 0.001; cadence (increase, all): F = 38.3, p < 0.001; double stride length (decrease, all): F = 33.8, p < 0.001; foot external rotation (increase during dialling, researching, selfie): F = 16.7, p < 0.001; stride length variability (increase): F = 11.7, p < 0.001; step width variability (increase): F = 5.3, p < 0.001; step width (Friedmann test and Wilcoxon Bonferroni-Holm-corrected post-hoc analyses, increase): Z = -2.3 to -2.9; p < 0.05); plantar pressure proportion (increase during reading and researching) (Z = -2.9; p < 0.01). The ability to keep usual gait quality during smartphone usage was systematically associated with the TMT B time regarding cadence and double stride length for reading (r = -0.37), dialling (r = -0.35) and taking a selfie (r = -0.34). Smartphone usage substantially impacts walking characteristics in most situations. Changes of gait patterns indicate higher cognitive loads and lower awareness. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of ambient light and age-related macular degeneration on precision walking.

PubMed

Alexander, M Scott; Lajoie, Kim; Neima, David R; Strath, Robert A; Robinovitch, Stephen N; Marigold, Daniel S

2014-08-01

To determine how age-related macular degeneration (AMD) and changes in ambient light affect the control of foot placement while walking. Ten older adults with AMD and 11 normal-sighted controls performed a precision walking task under normal (∼600 lx), dim (∼0.7 lx), and after a sudden reduction (∼600 to 0.7 lx) of light. The precision walking task involved subjects walking and stepping to the center of a series of irregularly spaced, low-contrast targets. Habitual visual acuity and contrast sensitivity and visual field function were also assessed. There were no differences between groups when performing the walking task in normal light (p > 0.05). In reduced lighting, older adults with AMD were less accurate and more variable when stepping across the targets compared to controls (p < 0.05). A sudden reduction of light proved the most challenging for this population. In the AMD group, contrast sensitivity and visual acuity were not significantly correlated with walking performance. Visual field thresholds in the AMD group were only associated with greater foot placement error and variability in the dim light walking condition (r = -0.69 to -0.87, p < 0.05). While walking performance is similar between groups in normal light, poor ambient lighting results in decreased foot placement accuracy in older adults with AMD. Improper foot placement while walking can lead to a fall and possible injury. Thus, to improve the mobility of those with AMD, strategies to enhance the environment in reduced lighting situations are necessary.

Excitability Changes in Intracortical Neural Circuits Induced by Differentially Controlled Walking Patterns

PubMed Central

Ito, Tomotaka; Tsubahara, Akio; Shinkoda, Koichi; Yoshimura, Yosuke; Kobara, Kenichi; Osaka, Hiroshi

2015-01-01

Our previous single-pulse transcranial magnetic stimulation (TMS) study revealed that excitability in the motor cortex can be altered by conscious control of walking relative to less conscious normal walking. However, substantial elements and underlying mechanisms for inducing walking-related cortical plasticity are still unknown. Hence, in this study we aimed to examine the characteristics of electromyographic (EMG) recordings obtained during different walking conditions, namely, symmetrical walking (SW), asymmetrical walking 1 (AW1), and asymmetrical walking 2 (AW2), with left to right stance duration ratios of 1:1, 1:2, and 2:1, respectively. Furthermore, we investigated the influence of three types of walking control on subsequent changes in the intracortical neural circuits. Prior to each type of 7-min walking task, EMG analyses of the left tibialis anterior (TA) and soleus (SOL) muscles during walking were performed following approximately 3 min of preparative walking. Paired-pulse TMS was used to measure short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in the left TA and SOL at baseline, immediately after the 7-min walking task, and 30 min post-task. EMG activity in the TA was significantly increased during AW1 and AW2 compared to during SW, whereas a significant difference in EMG activity of the SOL was observed only between AW1 and AW2. As for intracortical excitability, there was a significant alteration in SICI in the TA between SW and AW1, but not between SW and AW2. For the same amount of walking exercise, we found that the different methods used to control walking patterns induced different excitability changes in SICI. Our research shows that activation patterns associated with controlled leg muscles can alter post-exercise excitability in intracortical circuits. Therefore, how leg muscles are activated in a clinical setting could influence the outcome of walking in patients with stroke. PMID:25688972

Using dual tasks to test immediate transfer of training between naturalistic movements: a proof-of-principle study.

PubMed

Schaefer, Sydney Y; Lang, Catherine E

2012-01-01

Theories of motor learning predict that training a movement reduces the amount of attention needed for its performance (i.e., more automatic). If training one movement transfers, then the amount of attention needed for performing a second movement should also be reduced, as measured under dual task conditions. The authors' purpose was to test whether dual task paradigms are feasible for detecting transfer of training between two naturalistic movements. Immediately following motor training, subjects improved performance of a second untrained movement under single and dual task conditions. Subjects with no training did not. Improved performance in the untrained movement was likely due to transfer, and suggests that dual tasks may be feasible for detecting transfer between naturalistic actions.

Developmental changes in children's abilities to share and allocate attention in a dual task.

PubMed

Irwin-Chase, H; Burns, B

2000-09-01

Characterizing developmental changes in children's dual-task performance has been problematic because differences in divided attention abilities are easily confounded with differences in overall capacity. Two experiments showed that after individual differences in children's capacity for single-task performance were controlled for, age differences between second- (M = 8.1 years) and fifth-grade (M = 11.1 years) children did not exist in dual-task performance when tasks were of equal priority. However, when tasks had different priorities, only fifth-grade children could differentially allocate attention in the dual task. Results are discussed within the coordination hypothesis framework (see A. F. Kramer & J. L. Larish, 1996), which suggests that changes in dual-task performance with aging are due to changes in the ability to coordinate and control the allocation of attention. It is argued that linking the investigations of children's attention with research on attention and aging provides both methodological and theoretical benefits. Copyright 2000 Academic Press.

Closed head injury and perceptual processing in dual-task situations.

PubMed

Hein, G; Schubert, T; von Cramon, D Y

2005-01-01

Using a classical psychological refractory period (PRP) paradigm we investigated whether increased interference between dual-task input processes is one possible source of dual-task deficits in patients with closed-head injury (CHI). Patients and age-matched controls were asked to give speeded motor reactions to an auditory and a visual stimulus. The perceptual difficulty of the visual stimulus was manipulated by varying its intensity. The results of Experiment 1 showed that CHI patients suffer from increased interference between dual-task input processes, which is related to the salience of the visual stimulus. A second experiment indicated that this input interference may be specific to brain damage following CHI. It is not evident in other groups of neurological patients like Parkinson's disease patients. We conclude that the non-interfering processing of input stages in dual-tasks requires cognitive control. A decline in the control of input processes should be considered as one source of dual-task deficits in CHI patients.

Effects of interventions on normalizing step width during self-paced dual-belt treadmill walking with virtual reality, a randomised controlled trial.

PubMed

Oude Lansink, I L B; van Kouwenhove, L; Dijkstra, P U; Postema, K; Hijmans, J M

2017-10-01

Step width is increased during dual-belt treadmill walking, in self-paced mode with virtual reality. Generally a familiarization period is thought to be necessary to normalize step width. The aim of this randomised study was to analyze the effects of two interventions on step width, to reduce the familiarization period. We used the GRAIL (Gait Real-time Analysis Interactive Lab), a dual-belt treadmill with virtual reality in the self-paced mode. Thirty healthy young adults were randomly allocated to three groups and asked to walk at their preferred speed for 5min. In the first session, the control-group received no intervention, the 'walk-on-the-line'-group was instructed to walk on a line, projected on the between-belt gap of the treadmill and the feedback-group received feedback about their current step width and were asked to reduce it. Interventions started after 1min and lasted 1min. During the second session, 7-10days later, no interventions were given. Linear mixed modeling showed that interventions did not have an effect on step width after the intervention period in session 1. Initial step width (second 30s) of session 1 was larger than initial step width of session 2. Step width normalized after 2min and variation in step width stabilized after 1min. Interventions do not reduce step width after intervention period. A 2-min familiarization period is sufficient to normalize and stabilize step width, in healthy young adults, regardless of interventions. A standardized intervention to normalize step width is not necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

Locomotor Adaptation Improves Balance Control, Multitasking Ability and Reduces the Metabolic Cost of Postural Instability

NASA Technical Reports Server (NTRS)

Bloomberg, J. J.; Peters, B. T.; Mulavara, A. P.; Brady, R. A.; Batson, C. D.; Miller, C. A.; Ploutz-Snyder, R. J.; Guined, J. R.; Buxton, R. E.; Cohen, H. S.

2011-01-01

During exploration-class missions, sensorimotor disturbances may lead to disruption in the ability to ambulate and perform functional tasks during the initial introduction to a novel gravitational environment following a landing on a planetary surface. The overall goal of our current project is to develop a sensorimotor adaptability training program to facilitate rapid adaptation to these environments. We have developed a unique training system comprised of a treadmill placed on a motion-base facing a virtual visual scene. It provides an unstable walking surface combined with incongruent visual flow designed to enhance sensorimotor adaptability. Greater metabolic cost incurred during balance instability means more physical work is required during adaptation to new environments possibly affecting crewmembers? ability to perform mission critical tasks during early surface operations on planetary expeditions. The goal of this study was to characterize adaptation to a discordant sensory challenge across a number of performance modalities including locomotor stability, multi-tasking ability and metabolic cost. METHODS: Subjects (n=15) walked (4.0 km/h) on a treadmill for an 8 -minute baseline walking period followed by 20-minutes of walking (4.0 km/h) with support surface motion (0.3 Hz, sinusoidal lateral motion, peak amplitude 25.4 cm) provided by the treadmill/motion-base system. Stride frequency and auditory reaction time were collected as measures of locomotor stability and multi-tasking ability, respectively. Metabolic data (VO2) were collected via a portable metabolic gas analysis system. RESULTS: At the onset of lateral support surface motion, subj ects walking on our treadmill showed an increase in stride frequency and auditory reaction time indicating initial balance and multi-tasking disturbances. During the 20-minute adaptation period, balance control and multi-tasking performance improved. Similarly, throughout the 20-minute adaptation period, VO2 gradually decreased following an initial increase after the onset of support surface motion. DISCUSSION: Resu lts confirmed that walking in discordant conditions not only compromises locomotor stability and the ability to multi-task, but comes at a quantifiable metabolic cost. Importantly, like locomotor stability and multi-tasking ability, metabolic expenditure while walking in discordant sensory conditions improved during adaptation. This confirms that sensorimotor adaptability training can benefit multiple performance parameters central to the successful completion of critical mission tasks.

Instrumented Trail-Making Task to Differentiate Persons with No Cognitive Impairment, Amnestic Mild Cognitive Impairment, and Alzheimer Disease: A Proof of Concept Study.

PubMed

Zhou, He; Sabbagh, Marwan; Wyman, Rachel; Liebsack, Carolyn; Kunik, Mark E; Najafi, Bijan

2017-01-01

Objective and time-effective tools are needed to identify motor-cognitive impairment and facilitate early intervention. We examined the feasibility, accuracy, and reliability of an instrumented trail-making task (iTMT) using a wearable sensor to identify motor-cognitive impairment among older adults. Thirty subjects (age = 82.2 + 6.1 years, body mass index = 25.7 + 4.8, female = 43.3%) in 3 age-matched groups, 11 healthy, 10 with amnestic mild cognitive impairment (aMCI), and 9 with Alzheimer disease (AD), were recruited. Subjects completed iTMT, using a wearable sensor attached to the leg, which translates the motion of the ankle into a human-machine interface. iTMT tests included reaching to 5 indexed circles on a computer screen by moving the ankle-joint while standing. iTMT was quantified by the time required to reach all circles in the correct sequence. Three iTMT tests were designed, including numbers (1-5) positioned in a fixed (iTMTfixed) or random (iTMTrandom) order, or numbers (1-3) and letters (A and B) positioned in random order (iTMTnumber-letter). Each test was repeated twice to examine test-retest reliability. In addition, the conventional trail-making task (TMT A and B), Montreal Cognitive Assessment (MoCA), and dual-task cost (DTC: gait-speed difference between walking alone and walking while counting backward) were used as references. Re sults: Good-to-excellent reliability was achieved for all iTMT tests (intraclass correlation [ICC] = 0.742-0.836). Between-group difference was more pronounced, when using iTMTnumber-letter, with average completion time of 26.3 ± 12.4, 37.8 ± 14.1, and 61.8 ± 34.1 s, respectively, for healthy, aMCI, and AD groups (p = 0.006). Pairwise comparison suggested strong effect sizes between AD and healthy (Cohen's d = 1.384, p = 0.001) and between aMCI and AD (d = 0.923, p = 0.028). Significant correlation was observed when comparing iTMTnumber-letter with MoCA (r = -0.598, p = 0.001), TMT A (r = 0.519, p = 0.006), TMT B (r = 0.666, p < 0.001), and DTC (r = 0.713, p < 0.001). This study demonstrated proof of concept of a simple, safe, and practical iTMT system with promising results to identify cognitive and dual-task ability impairment among older adults, including those with aMCI and AD. Future studies need to confirm these observations in larger samples, as well as iTMT's ability to track motor-cognitive decline over time. © 2016 S. Karger AG, Basel.

Increased reaction times and reduced response preparation already starts at middle age

PubMed Central

Wolkorte, Ria; Kamphuis, Janine; Zijdewind, Inge

2014-01-01

Generalized slowing characterizes aging and there is some evidence to suggest that this slowing already starts at midlife. This study aims to assess reaction time changes while performing a concurrent low-force and high-force motor task in young and middle-aged subjects. The high-force motor task is designed to induce muscle fatigue and thereby progressively increase the attentional demands. Twenty-five young (20–30 years, 12 males) and 16 middle-aged (35–55 years, 9 males) adults performed an auditory two-choice reaction time task (CRT) with and without a concurrent low- or high-force motor task. The CRT required subjects to respond to two different stimuli that occurred with a probability of 70 or 30%. The motor task consisted of index finger abduction, at either 10% (10%-dual-task) or 30% (30%-dual-task) of maximal voluntary force. Cognitive task performance was measured as percentage of correct responses and reaction times. Middle-aged subjects responded slower on the frequent but more accurately on the infrequent stimuli of CRT than young subjects. Both young and middle-aged subjects showed increased errors and reaction times while performing under dual-task conditions and both outcome measures increased further under fatiguing conditions. Only under 30%-dual-task demands, an age-effect on dual-task performance was present. Both single- and dual-task conditions showed that already at mid-life response preparation is seriously declined and that subjects implement different strategies to perform a CRT task. PMID:24808862

The effects of prosthetic foot stiffness on transtibial amputee walking mechanics and balance control during turning.

PubMed

Shell, Courtney E; Segal, Ava D; Klute, Glenn K; Neptune, Richard R

2017-11-01

Little evidence exists regarding how prosthesis design characteristics affect performance in tasks that challenge mediolateral balance such as turning. This study assesses the influence of prosthetic foot stiffness on amputee walking mechanics and balance control during a continuous turning task. Three-dimensional kinematic and kinetic data were collected from eight unilateral transtibial amputees as they walked overground at self-selected speed clockwise and counterclockwise around a 1-meter circle and along a straight line. Subjects performed the walking tasks wearing three different ankle-foot prostheses that spanned a range of sagittal- and coronal-plane stiffness levels. A decrease in stiffness increased residual ankle dorsiflexion (10-13°), caused smaller adaptations (<5°) in proximal joint angles, decreased residual and increased intact limb body support, increased residual limb propulsion and increased intact limb braking for all tasks. While changes in sagittal-plane joint work due to decreased stiffness were generally consistent across tasks, effects on coronal-plane hip work were task-dependent. When the residual limb was on the inside of the turn and during straight-line walking, coronal-plane hip work increased and coronal-plane peak-to-peak range of whole-body angular momentum decreased with decreased stiffness. Changes in sagittal-plane kinematics and kinetics were similar to those previously observed in straight-line walking. Mediolateral balance improved with decreased stiffness, but adaptations in coronal-plane angles, work and ground reaction force impulses were less systematic than those in sagittal-plane measures. Effects of stiffness varied with the residual limb inside versus outside the turn, which suggests that actively adjusting stiffness to turn direction may be beneficial. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dual-Task Interference When A Response is Not Required

NASA Technical Reports Server (NTRS)

VanSelst, Mark; Johnston, James C.; Shafto, Michael (Technical Monitor)

2002-01-01

When subjects are required to respond to two stimuli presented in rapid succession, responses to the second stimulus are delayed. Such dual-task interference has been attributed to a fundamental processing bottleneck preventing simultaneous processing on both tasks. Two experiments show dual-task interference even when the first task does not require a response. The observed interference is caused by a bottleneck in central cognitive processing, rather than in response initiation or execution.

Age-related differences in dual task performance: A cross-sectional study on women.

PubMed

Brustio, Paolo R; Magistro, Daniele; Rabaglietti, Emanuela; Liubicich, Monica E

2017-02-01

Simultaneous performances of motor and attention-demanding tasks are common in activities of everyday life. The present cross-sectional study examined the changes and age-related differences on mobility performance with an additional cognitive or motor task, and evaluated the relative dual-task cost (DTC) on the motor performance in young, middle-aged and older women. A total of 30 young (mean age 25.12 ± 3.00 years), 30 middle-aged (mean age 47.82 ± 5.06 years) and 30 older women (mean age 72.74 ± 5.95 years) were recruited. Participants carried out: (i) single task: Timed Up & Go Test; (ii) cognitive dual-task: Timed Up & Go Test while counting backwards by three; (iii) manual dual-task: Timed Up & Go Test while carrying a glass of water. A repeated measures anova with between-factor as age groups and within-factor as tasks was carried out to assess the effect of aging on the performance of mobility tasks. DTC was calculated as ([performance in single-task - performance in dual-task] / performance in single task) × 100%. One-way ancova were carried out to compare the DTC among the three age groups. A significant interaction between age groups and task (F 4,172  = 6.716, P < 0.001, partial η 2  = 0.135) was observed. Specifically, older women showed a worse mobility performance under dual-task condition compared with young and middle-aged groups. Furthermore, DTC differences in cognitive task were observed in older women compared with younger and middle-aged women (F 2,86  = 7.649, P < 0.001, partial η 2  = 0.151), but not in manual task. Dual-task conditions might affect mobility performance differently across the lifespan, and could be particularly challenging in older women. Geriatr Gerontol Int 2017; 17: 315-321. © 2015 Japan Geriatrics Society.

The efficacy of treadmill training with and without projected visual context for improving walking ability and reducing fall incidence and fear of falling in older adults with fall-related hip fracture: a randomized controlled trial.

PubMed

van Ooijen, Mariëlle W; Roerdink, Melvyn; Trekop, Marga; Janssen, Thomas W J; Beek, Peter J

2016-12-28

The ability to adjust walking to environmental context is often reduced in older adults and, partly as result of this, falls are common in this population. A treadmill with visual context projected on its belt (e.g., obstacles and targets) allows for practicing step adjustments relative to that context, while concurrently exploiting the great amount of walking practice associated with conventional treadmill training. The present study was conducted to compare the efficacy of adaptability treadmill training, conventional treadmill training and usual physical therapy in improving walking ability and reducing fear of falling and fall incidence in older adults during rehabilitation from a fall-related hip fracture. In this parallel-group, open randomized controlled trial, seventy older adults with a recent fall-related hip fracture (83.3 ± 6.7 years, mean ± standard deviation) were recruited from inpatient rehabilitation care and block randomized to six weeks inpatient adaptability treadmill training (n = 24), conventional treadmill training (n = 23) or usual physical therapy (n = 23). Group allocation was only blind for assessors. Measures related to walking ability were assessed as the primary outcome before and after the intervention and at 4-week and 12-month follow-up. Secondary outcomes included general health, fear of falling, fall rate and proportion of fallers. Measures of general walking ability, general health and fear of falling improved significantly over time. Significant differences among the three intervention groups were only found for the Functional Ambulation Category and the dual-task effect on walking speed, which were in favor of respectively conventional treadmill training and adaptability treadmill training. Overall, adaptability treadmill training, conventional treadmill training and usual physical therapy resulted in similar effects on walking ability, fear of falling and fall incidence in older adults rehabilitating from a fall-related hip fracture. Additional post hoc subgroup analyses, with stratification for pre-fracture tolerated walking distance and executive function, revealed several intervention effects in favor of adaptability and conventional treadmill training, indicating superiority over usual physical therapy for certain subgroups. Future well-powered studies are necessary to univocally identify the characteristics of individuals who will benefit most from a particular intervention. The Netherlands Trial Register ( NTR3222 , 3 January 2012).

Effect of subthalamic nucleus deep brain stimulation on dual-task cognitive and motor performance in isolated dystonia.

PubMed

Mills, Kelly A; Markun, Leslie C; San Luciano, Marta; Rizk, Rami; Allen, I Elaine; Racine, Caroline A; Starr, Philip A; Alberts, Jay L; Ostrem, Jill L

2015-04-01

Subthalamic nucleus (STN) deep brain stimulation (DBS) can improve motor complications of Parkinson's disease (PD) but may worsen specific cognitive functions. The effect of STN DBS on cognitive function in dystonia patients is less clear. Previous reports indicate that bilateral STN stimulation in patients with PD amplifies the decrement in cognitive-motor dual-task performance seen when moving from a single-task to dual-task paradigm. We aimed to determine if the effect of bilateral STN DBS on dual-task performance in isolated patients with dystonia, who have less cognitive impairment and no dementia, is similar to that seen in PD. Eight isolated predominantly cervical patients with dystonia treated with bilateral STN DBS, with average dystonia duration of 10.5 years and Montreal Cognitive Assessment score of 26.5, completed working memory (n-back) and motor (forced-maintenance) tests under single-task and dual-task conditions while on and off DBS. A multivariate, repeated-measures analysis of variance showed no effect of stimulation status (On vs Off) on working memory (F=0.75, p=0.39) or motor function (F=0.22, p=0.69) when performed under single-task conditions, though as working memory task difficulty increased, stimulation disrupted the accuracy of force-tracking. There was a very small worsening in working memory performance (F=9.14, p=0.019) when moving from single-task to dual-tasks when using the 'dual-task loss' analysis. This study suggests the effect of STN DBS on working memory and attention may be much less consequential in patients with dystonia than has been reported in PD. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Effect of subthalamic nucleus deep brain stimulation on dual-task cognitive and motor performance in isolated dystonia

PubMed Central

Mills, Kelly A; Markun, Leslie C; Luciano, Marta San; Rizk, Rami; Allen, I Elaine; Racine, Caroline A; Starr, Philip A; Alberts, Jay L; Ostrem, Jill L

2015-01-01

Objective Subthalamic nucleus (STN) deep brain stimulation (DBS) can improve motor complications of Parkinson's disease (PD) but may worsen specific cognitive functions. The effect of STN DBS on cognitive function in dystonia patients is less clear. Previous reports indicate that bilateral STN stimulation in patients with PD amplifies the decrement in cognitive-motor dual-task performance seen when moving from a single-task to dual-task paradigm. We aimed to determine if the effect of bilateral STN DBS on dual-task performance in isolated patients with dystonia, who have less cognitive impairment and no dementia, is similar to that seen in PD. Methods Eight isolated predominantly cervical patients with dystonia treated with bilateral STN DBS, with average dystonia duration of 10.5 years and Montreal Cognitive Assessment score of 26.5, completed working memory (n-back) and motor (forced-maintenance) tests under single-task and dual-task conditions while on and off DBS. Results A multivariate, repeated-measures analysis of variance showed no effect of stimulation status (On vs Off) on working memory (F=0.75, p=0.39) or motor function (F=0.22, p=0.69) when performed under single-task conditions, though as working memory task difficulty increased, stimulation disrupted the accuracy of force-tracking. There was a very small worsening in working memory performance (F=9.14, p=0.019) when moving from single-task to dual-tasks when using the ‘dual-task loss’ analysis. Conclusions This study suggests the effect of STN DBS on working memory and attention may be much less consequential in patients with dystonia than has been reported in PD. PMID:25012202

Varied overground walking-task practice versus body-weight-supported treadmill training in ambulatory adults within one year of stroke: a randomized controlled trial protocol.

PubMed

DePaul, Vincent G; Wishart, Laurie R; Richardson, Julie; Lee, Timothy D; Thabane, Lehana

2011-10-21

Although task-oriented training has been shown to improve walking outcomes after stroke, it is not yet clear whether one task-oriented approach is superior to another. The purpose of this study is to compare the effectiveness of the Motor Learning Walking Program (MLWP), a varied overground walking task program consistent with key motor learning principles, to body-weight-supported treadmill training (BWSTT) in community-dwelling, ambulatory, adults within 1 year of stroke. A parallel, randomized controlled trial with stratification by baseline gait speed will be conducted. Allocation will be controlled by a central randomization service and participants will be allocated to the two active intervention groups (1:1) using a permuted block randomization process. Seventy participants will be assigned to one of two 15-session training programs. In MLWP, one physiotherapist will supervise practice of various overground walking tasks. Instructions, feedback, and guidance will be provided in a manner that facilitates self-evaluation and problem solving. In BWSTT, training will emphasize repetition of the normal gait cycle while supported over a treadmill, assisted by up to three physiotherapists. Outcomes will be assessed by a blinded assessor at baseline, post-intervention and at 2-month follow-up. The primary outcome will be post-intervention comfortable gait speed. Secondary outcomes include fast gait speed, walking endurance, balance self-efficacy, participation in community mobility, health-related quality of life, and goal attainment. Groups will be compared using analysis of covariance with baseline gait speed strata as the single covariate. Intention-to-treat analysis will be used. In order to direct clinicians, patients, and other health decision-makers, there is a need for a head-to-head comparison of different approaches to active, task-related walking training after stroke. We hypothesize that outcomes will be optimized through the application of a task-related training program that is consistent with key motor learning principles related to practice, guidance and feedback. ClinicalTrials.gov # NCT00561405.

Varied overground walking-task practice versus body-weight-supported treadmill training in ambulatory adults within one year of stroke: a randomized controlled trial protocol

PubMed Central

2011-01-01

Background Although task-oriented training has been shown to improve walking outcomes after stroke, it is not yet clear whether one task-oriented approach is superior to another. The purpose of this study is to compare the effectiveness of the Motor Learning Walking Program (MLWP), a varied overground walking task program consistent with key motor learning principles, to body-weight-supported treadmill training (BWSTT) in community-dwelling, ambulatory, adults within 1 year of stroke. Methods/Design A parallel, randomized controlled trial with stratification by baseline gait speed will be conducted. Allocation will be controlled by a central randomization service and participants will be allocated to the two active intervention groups (1:1) using a permuted block randomization process. Seventy participants will be assigned to one of two 15-session training programs. In MLWP, one physiotherapist will supervise practice of various overground walking tasks. Instructions, feedback, and guidance will be provided in a manner that facilitates self-evaluation and problem solving. In BWSTT, training will emphasize repetition of the normal gait cycle while supported over a treadmill, assisted by up to three physiotherapists. Outcomes will be assessed by a blinded assessor at baseline, post-intervention and at 2-month follow-up. The primary outcome will be post-intervention comfortable gait speed. Secondary outcomes include fast gait speed, walking endurance, balance self-efficacy, participation in community mobility, health-related quality of life, and goal attainment. Groups will be compared using analysis of covariance with baseline gait speed strata as the single covariate. Intention-to-treat analysis will be used. Discussion In order to direct clinicians, patients, and other health decision-makers, there is a need for a head-to-head comparison of different approaches to active, task-related walking training after stroke. We hypothesize that outcomes will be optimized through the application of a task-related training program that is consistent with key motor learning principles related to practice, guidance and feedback. Trial Registration ClinicalTrials.gov # NCT00561405 PMID:22018267

The effects of display-control I/O, compatibility, and integrality on dual-task performance and subjective workload

NASA Technical Reports Server (NTRS)

Tsang, Pamela S.; Hart, Sandra G.; Vidulich, Michael A.

1987-01-01

The utility of speech technology was evaluated in terms of three dual task principles: resource competition between the time shared tasks, stimulus central processing response compatibility, and task integrality. Empirical support for these principles was reviewed. Two studies investigating the interactive effects of the three principles were described. Objective performance and subjective workload ratings for both single and dual tasks were examined. It was found that the single task measures were not necessarily good predictors for the dual task measures. It was shown that all three principles played an important role in determining an optimal task configuration. This was reflected in both the performance measures and the subjective measures. Therefore, consideration of all three principles is required to insure proper use of speech technology in a complex environment.

Using dual tasks to test immediate transfer of training between naturalistic movements: A proof-of-principle study

PubMed Central

Schaefer, Sydney Y.; Lang, Catherine E.

2012-01-01

Theories of motor learning predict that training a movement reduces the amount of attention needed for its performance (i.e. more automatic). If training one movement transfers, then the amount of attention needed for performing a second movement should also be reduced, as measured under dual task conditions. The purpose of this study was to test whether dual task paradigms are feasible for detecting transfer of training between two naturalistic movements. Immediately following motor training, subjects improved performance of a second untrained movement under both single and dual task conditions. Subjects with no training did not. Improved performance in the untrained movement was likely due to transfer, and suggests that dual tasks may be feasible for detecting transfer between naturalistic actions. PMID:22934682

Age-Related Interference between the Selection of Input-Output Modality Mappings and Postural Control—a Pilot Study

PubMed Central

Stelzel, Christine; Schauenburg, Gesche; Rapp, Michael A.; Heinzel, Stephan; Granacher, Urs

2017-01-01

Age-related decline in executive functions and postural control due to degenerative processes in the central nervous system have been related to increased fall-risk in old age. Many studies have shown cognitive-postural dual-task interference in old adults, but research on the role of specific executive functions in this context has just begun. In this study, we addressed the question whether postural control is impaired depending on the coordination of concurrent response-selection processes related to the compatibility of input and output modality mappings as compared to impairments related to working-memory load in the comparison of cognitive dual and single tasks. Specifically, we measured total center of pressure (CoP) displacements in healthy female participants aged 19–30 and 66–84 years while they performed different versions of a spatial one-back working memory task during semi-tandem stance on an unstable surface (i.e., balance pad) while standing on a force plate. The specific working-memory tasks comprised: (i) modality compatible single tasks (i.e., visual-manual or auditory-vocal tasks), (ii) modality compatible dual tasks (i.e., visual-manual and auditory-vocal tasks), (iii) modality incompatible single tasks (i.e., visual-vocal or auditory-manual tasks), and (iv) modality incompatible dual tasks (i.e., visual-vocal and auditory-manual tasks). In addition, participants performed the same tasks while sitting. As expected from previous research, old adults showed generally impaired performance under high working-memory load (i.e., dual vs. single one-back task). In addition, modality compatibility affected one-back performance in dual-task but not in single-task conditions with strikingly pronounced impairments in old adults. Notably, the modality incompatible dual task also resulted in a selective increase in total CoP displacements compared to the modality compatible dual task in the old but not in the young participants. These results suggest that in addition to effects of working-memory load, processes related to simultaneously overcoming special linkages between input- and output modalities interfere with postural control in old but not in young female adults. Our preliminary data provide further evidence for the involvement of cognitive control processes in postural tasks. PMID:28484411

Posture-Motor and Posture-Ideomotor Dual-Tasking: A Putative Marker of Psychomotor Retardation and Depressive Rumination in Patients With Major Depressive Disorder.

PubMed

Aftanas, Lyubomir I; Bazanova, Olga M; Novozhilova, Nataliya V

2018-01-01

Background: Recent studies have demonstrated that the assessment of postural performance may be a potentially reliable and objective marker of the psychomotor retardation (PMR) in the major depressive disorder (MDD). One of the important facets of MDD-related PMR is reflected in disrupted central mechanisms of psychomotor control, heavily influenced by compelling maladaptive depressive rumination. In view of this we designed a research paradigm that included sequential execution of simple single-posture task followed by more challenging divided attention posture tasks, involving concurring motor and ideomotor workloads. Another difficulty dimension assumed executing of all the tasks with eyes open (EO) (easy) and closed (EC) (difficult) conditions. We aimed at investigating the interplay between the severity of MDD, depressive rumination, and efficiency of postural performance. Methods: Compared with 24 age- and body mass index-matched healthy controls (HCs), 26 patients with MDD sequentially executed three experimental tasks: (1) single-posture task of maintaining a quiet stance (ST), (2) actual posture-motor dual task (AMT); and (3) mental/imaginary posture-motor dual task (MMT). All the tasks were performed in the EO and the EC conditions. The primary dependent variable was the amount of kinetic energy ( E ) expended for the center of pressure deviations (CoPDs), whereas the absolute divided attention cost index showed energy cost to the dual-tasking vs. the single-posture task according to the formula: Δ E = ( E Dual-task - E Single-task ). Results: The signs of PMR in the MDD group were objectively indexed by deficient posture control in the EC condition along with overall slowness of fine motor and ideomotor activity. Another important and probably more challenging feature of the findings was that the posture deficit manifested in the ST condition was substantially and significantly attenuated in the MMT and AMT performance dual-tasking activity. A multiple linear regression analysis evidenced further that the dual-tasking energy cost (i.e., Δ E ) significantly predicted clinical scores of severity of MDD and depressive rumination. Conclusion: The findings allow to suggest that execution of concurrent actual or imaginary fine motor task with closed visual input deallocates attentional resources from compelling maladaptive depressive rumination thereby attenuating severity of absolute dual-tasking energy costs for balance maintenance in patients with MDD. Significance: Quantitative assessment of PMR through measures of the postural performance in dual-tasking may be useful to capture the negative impact of past depressive episodes, optimize the personalized treatment selection, and improve the understanding of the pathophysiological mechanisms underlying MDD.

Effects of the Addition of a Dual Task to a Supervised Physical Exercise Program on Older Adults' Cognitive Performance.

PubMed

Ansai, Juliana Hotta; de Andrade, Larissa Pires; de Souza Buto, Marcele Stephanie; de Vassimon Barroso, Verena; Farche, Ana Claudia Silva; Rossi, Paulo Giusti; de Medeiros Takahashi, Anielle Cristhine

2017-04-01

The purpose of this study was to investigate the effects of the addition of a dual task to multicomponent training on cognition of active older adults. Eighty physically active older adults were divided into an intervention group (IG) and a control group (CG). Both groups performed multicomponent training over 12 weeks. The IG simultaneously performed exercises and cognitive tasks. The Mini-Mental State Examination, the Montreal Cognitive Assessment, and the Clock Drawing Test were used for cognitive assessments. The Timed Up and Go Test associated with a cognitive task was used for dual-task assessment. Significant interactions were not observed between groups in terms of the cognitive variables or the dual-task performance. An interaction was observed only for Timed Up and Go Test performance, which was better in the CG than in the IG. Active older adults showed no improvement in cognition following the addition of the dual task to the multicomponent training.

Walking the Tightrope: Christian Colleges and Universities in a Time of Change

ERIC Educational Resources Information Center

Henck, Anita Fitzgerald

2011-01-01

Leadership of Christian higher education in the United States is in a period of significant change. Yet, the dual accountability--to higher education accreditation and to faith communities--means that Christian colleges and universities walk a tightrope between these two entities, their expectations, and their values. The challenge for U.S.…

From Chalk and Talk to Walking the Walk: Facilitating Dynamic Learning Contexts for Entrepreneurship Students in Fast-Tracking Innovations

ERIC Educational Resources Information Center

Gilbert, David H.

2012-01-01

Purpose: The purpose of this paper is to examine the notion of designing and developing applied, industry-engaged learning environments that embrace ambiguity and uncertainty in overcoming pedagogical inertia in educating young entrepreneurs and innovators. The research reported on proposes a solution to the dual expectations of producing…

The effect of hospital unit layout on nurse walking behavior.

PubMed

Yi, Lu; Seo, Hyun-Bo

2012-01-01

To confirm a new method for the research question, "How do different hospital unit layouts affect nurses' walking behavior and distance?" Concern is renewed regarding nurses' long walking distances because of the trend toward larger patient rooms with family areas inside, resulting in a larger overall unit size. Studies have found unit design characteristics that support nurses' efficient walking, but few have done it in units designed for patient- and family-centered care. To examine the effect of unit design on nurses' walking behavior, the authors propose a new method of observing a specific task. The authors observed nurses during the task of medication administration. Contrary to their hypotheses, results showed: (1) Experienced nurses had more unnecessary stops and longer walking distances than new nurses because of interactions; and (2) nurses in the smaller wing of the unit walked more than those in the larger wing of the same unit. The authors posit that the closeness between the nurses' path to the medication supply room and the central nurses' station affected the frequency of interactions and prompted a deviation from the shortest and most efficient path during medication administration. Observing a specific task to identify the effect of unit layout was effective, determining that overall unit shape or unit layout type might not be a good predictor of nurses' walking behavior; instead the characteristics of the path that connects functional spaces such as patient room and medication area might better predict nurses' walking behavior.

Task difficulty has no effect on haptic anchoring during tandem walking in young and older adults.

PubMed

Costa, Andréia Abud da Silva; Santos, Luciana Oliveira Dos; Mauerberg-deCastro, Eliane; Moraes, Renato

2018-02-14

This study assessed the contribution of the "anchor system's" haptic information to balance control during walking at two levels of difficulty. Seventeen young adults and seventeen older adults performed 20 randomized trials of tandem walking in a straight line, on level ground and on a slightly-raised balance beam, both with and without the use of the anchors. The anchor consists of two flexible cables, whose ends participants hold in each hand, to which weights (125 g) are attached at the opposing ends, and which rest on the ground. As the participants walk, they pull on the cables, dragging the anchors. Spatiotemporal gait variables (step speed and single- and double-support duration) were processed using retro-reflective markers on anatomical sites. An accelerometer positioned in the cervical region registered trunk acceleration. Walking on the balance beam increased single- and double-support duration and reduced step speed in older adults, which suggests that this condition was more difficult than walking on the level ground. The anchors reduced trunk acceleration in the frontal plane, but the level of difficulty of the walking task showed no effect. Thus, varying the difficulty of the task had no influence on the way in which participants used the anchor system while tandem walking. The older adults exhibited more difficulty in walking on the balance beam as compared to the younger adults; however, the effect of the anchor system was similar in both groups. Copyright © 2017 Elsevier B.V. All rights reserved.

Does walking speed mediate the association between visual impairment and self-report of mobility disability? The Salisbury Eye Evaluation Study.

PubMed

Swenor, Bonnielin K; Bandeen-Roche, Karen; Muñoz, Beatriz; West, Sheila K

2014-08-01

To determine whether performance speeds mediate the association between visual impairment and self-reported mobility disability over an 8-year period. Longitudinal analysis. Salisbury, Maryland. Salisbury Eye Evaluation Study participants aged 65 and older (N=2,520). Visual impairment was defined as best-corrected visual acuity worse than 20/40 in the better-seeing eye or visual field less than 20°. Self-reported mobility disability on three tasks was assessed: walking up stairs, walking down stairs, and walking 150 feet. Performance speed on three similar tasks was measured: walking up steps (steps/s), walking down steps (steps/s), and walking 4 m (m/s). For each year of observation, the odds of reporting mobility disability was significantly greater for participants who were visually impaired (VI) than for those who were not (NVI) (odds ratio (OR) difficulty walking up steps=1.58, 95% confidence interval (CI)=1.32-1.89; OR difficulty walking down steps=1.90, 95% CI=1.59-2.28; OR difficulty walking 150 feet=2.11, 95% CI=1.77-2.51). Once performance speed on a similar mobility task was included in the models, VI participants were no longer more likely to report mobility disability than those who were NVI (OR difficulty walking up steps=0.84, 95% CI=0.65-1.11; OR difficulty walking down steps=0.96, 95% CI=0.74-1.24; OR difficulty walking 150 feet=1.22, 95% CI=0.98-1.50). Slower performance speed in VI individuals largely accounted for the difference in the odds of reporting mobility disability, suggesting that VI older adults walk slower and are therefore more likely to report mobility disability than those who are NVI. Improving mobility performance in older adults with visual impairment may minimize the perception of mobility disability. © 2014, Copyright the Authors Journal compilation © 2014, The American Geriatrics Society.

Transcranial Direct Current Stimulation to Enhance Dual-Task Gait Training in Parkinson's Disease: A Pilot RCT.

PubMed

Schabrun, Siobhan M; Lamont, Robyn M; Brauer, Sandra G

2016-01-01

To investigate the feasibility and safety of a combined anodal transcranial direct current stimulation (tDCS) and dual task gait training intervention in people with Parkinson's Disease (PD) and to provide data to support a sample size calculation for a fully powered trial should trends of effectiveness be present. A pilot, randomized, double-blind, sham-controlled parallel group trial with 12 week follow-up. A university physiotherapy department. Sixteen participants diagnosed with PD received nine dual task gait training sessions over 3 weeks. Participants were randomized to receive either active or sham tDCS applied for the first 20 minutes of each session. The primary outcome was gait speed while undertaking concurrent cognitive tasks (word lists, counting, conversation). Secondary measures included step length, cadence, Timed Up and Go, bradykinesia and motor speed. Gait speed, step length and cadence improved in both groups, under all dual task conditions. This effect was maintained at follow-up. There was no difference between the active and sham tDCS groups. Time taken to perform the TUGwords also improved, with no difference between groups. The active tDCS group did however increase their correct cognitive response rate during the TUGwords and TUGcount. Bradykinesia improved after training in both groups. Three weeks of dual task gait training resulted in improved gait under dual task conditions, and bradykinesia, immediately following training and at 12 weeks follow-up. The only parameter enhanced by tDCS was the number of correct responses while performing the dual task TUG. tDCS applied to M1 may not be an effective adjunct to dual task gait training in PD. Australia-New Zealand Clinical Trials Registry ACTRN12613001093774.

Cognitive pitfall! Videogame players are not immune to dual-task costs.

PubMed

Donohue, Sarah E; James, Brittany; Eslick, Andrea N; Mitroff, Stephen R

2012-07-01

With modern technological advances, we often find ourselves dividing our attention between multiple tasks. While this may seem a productive way to live, our attentional capacity is limited, and this yields costs in one or more of the many tasks that we try to do. Some people believe that they are immune to the costs of multitasking and commonly engage in potentially dangerous behavior, such as driving while talking on the phone. But are some groups of individuals indeed immune to dual-task costs? This study examines whether avid action videogame players, who have been shown to have heightened attentional capacities, are particularly adept multitaskers. Participants completed three visually demanding experimental paradigms (a driving videogame, a multiple-object-tracking task, and a visual search), with and without answering unrelated questions via a speakerphone (i.e., with and without a dual-task component). All of the participants, videogame players and nonvideogame players alike, performed worse while engaging in the additional dual task for all three paradigms. This suggests that extensive videogame experience may not offer immunity from dual-task costs.

Dual Learning Processes in Interactive Skill Acquisition

ERIC Educational Resources Information Center

Fu, Wai-Tat; Anderson, John R.

2008-01-01

Acquisition of interactive skills involves the use of internal and external cues. Experiment 1 showed that when actions were interdependent, learning was effective with and without external cues in the single-task condition but was effective only with the presence of external cues in the dual-task condition. In the dual-task condition, actions…

Monitoring supports performance in a dual-task paradigm involving a risky decision-making task and a working memory task

PubMed Central

Gathmann, Bettina; Schiebener, Johannes; Wolf, Oliver T.; Brand, Matthias

2015-01-01

Performing two cognitively demanding tasks at the same time is known to decrease performance. The current study investigates the underlying executive functions of a dual-tasking situation involving the simultaneous performance of decision making under explicit risk and a working memory task. It is suggested that making a decision and performing a working memory task at the same time should particularly require monitoring—an executive control process supervising behavior and the state of processing on two tasks. To test the role of a supervisory/monitoring function in such a dual-tasking situation we investigated 122 participants with the Game of Dice Task plus 2-back task (GDT plus 2-back task). This dual task requires participants to make decisions under risk and to perform a 2-back working memory task at the same time. Furthermore, a task measuring a set of several executive functions gathered in the term concept formation (Modified Card Sorting Test, MCST) and the newly developed Balanced Switching Task (BST), measuring monitoring in particular, were used. The results demonstrate that concept formation and monitoring are involved in the simultaneous performance of decision making under risk and a working memory task. In particular, the mediation analysis revealed that BST performance partially mediates the influence of MCST performance on the GDT plus 2-back task. These findings suggest that monitoring is one important subfunction for superior performance in a dual-tasking situation including decision making under risk and a working memory task. PMID:25741308

Detection of Acute and Long-Term Effects of Concussion: Dual-Task Gait Balance Control Versus Computerized Neurocognitive Test.

PubMed

Howell, David R; Osternig, Louis R; Chou, Li-Shan

2018-02-16

To examine the acute (within 72h of injury) and long-term (2mo postinjury) independent associations between objective dual-task gait balance and neurocognitive measurements among adolescents and young adults with a concussion and matched controls. Longitudinal case-control. Motion analysis laboratory. A total of 95 participants completed the study: 51 who sustained a concussion (mean age, 17.5±3.3y; 71% men) and 44 controls (mean age, 17.7±2.9y; 72% men). Participants who sustained a concussion underwent a dual-task gait analysis and computerized neurocognitive testing within 72 hours of injury and again 2 months later. Uninjured controls also completed the same test protocol in similar time increments. Not applicable. We compared dual-task gait balance control and computerized neurocognitive test performance between groups using independent samples t tests. Multivariable binary logistic regression models were then constructed for each testing time to determine the association between group membership (concussion vs control), dual-task gait balance control, and neurocognitive function. Medial-lateral center-of-mass displacement during dual-task gait was independently associated with group membership at the initial test (adjusted odds ratio [aOR], 2.432; 95% confidence interval [CI], 1.269-4.661) and 2-month follow-up test (aOR, 1.817; 95% CI, 1.014-3.256) tests. Visual memory composite scores were significantly associated with group membership at the initial hour postinjury time point (aOR, .953; 95% CI, .833-.998). However, the combination of computerized neurocognitive test variables did not predict dual-task gait balance control for participants with concussion, and no single neurocognitive variable was associated with dual-task gait balance control at either testing time. Dual-task assessments concurrently evaluating gait and cognitive performance may allow for the detection of persistent deficits beyond those detected by computerized neurocognitive deficits alone. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Increased integrity of white matter pathways after dual n-back training.

PubMed

Salminen, Tiina; Mårtensson, Johan; Schubert, Torsten; Kühn, Simone

2016-06-01

Dual n-back WM training has been shown to produce broad transfer effects to different untrained cognitive functions. The task is demanding to the cognitive system because it includes a bi-modal (auditory and visual) dual-task component. A previous WM training study showed increased white matter integrity in the parietal lobe as well as the anterior part of the corpus callosum after visual n-back training. We investigated dual n-back training-related changes in white matter pathways. We anticipated dual n-back training to increase white matter integrity in pathways that connect brain regions related to WM processes. Additionally, we hypothesized that dual n-back training would produce more brain-wide white matter changes than single n-back training because of the involvement of two modalities and the additional dual-task coordination component of the task. The dual n-back training group showed increased white matter integrity (reflected as increased fractional anisotropy, FA) after training. The effects were mostly left lateralized as compared with changes from pretest to posttest in the passive and active control groups. Additionally, significant effects were observed in the anterior part of the corpus callosum, when the training group was compared with the passive control group. There were no changes in pretest to posttest FA changes between the passive and active control groups. The results therefore show that dual n-back training produces increased integrity in white matter pathways connecting different brain regions. The results are discussed in reference to the bi-modal dual-task component of the training task. Copyright © 2016 Elsevier Inc. All rights reserved.

Towards a Generic Behaviour Modelling Interface

DTIC Science & Technology

2010-10-01

walking and riding a bicycle , but we only have PSF’s that can be used to predict walking speed. How should we then apply these PSF’s to the (in some...aspects similar) task of riding a bicycle ? The third problem has to do with expanding the simulation with new tasks and PSF’s. Since PSF’s are...degraded (e.g. use of mobile phone while driving) or some actions should not be executed at all (e.g. walking and riding a bicycle at the same time). It

Perceptual-motor regulation in locomotor pointing while approaching a curb.

PubMed

Andel, Steven van; Cole, Michael H; Pepping, Gert-Jan

2018-02-01

Locomotor pointing is a task that has been the focus of research in the context of sport (e.g. long jumping and cricket) as well as normal walking. Collectively, these studies have produced a broad understanding of locomotor pointing, but generalizability has been limited to laboratory type tasks and/or tasks with high spatial demands. The current study aimed to generalize previous findings in locomotor pointing to the common daily task of approaching and stepping on to a curb. Sixteen people completed 33 repetitions of a task that required them to walk up to and step onto a curb. Information about their foot placement was collected using a combination of measures derived from a pressure-sensitive walkway and video data. Variables related to perceptual-motor regulation were analyzed on an inter-trial, intra-step and inter-step level. Similar to previous studies, analysis of the foot placements showed that, variability in foot placement decreased as the participants drew closer to the curb. Regulation seemed to be initiated earlier in this study compared to previous studies, as shown by a decreasing variability in foot placement as early as eight steps before reaching the curb. Furthermore, it was shown that when walking up to the curb, most people regulated their walk in a way so as to achieve minimal variability in the foot placement on top of the curb, rather than a placement in front of the curb. Combined, these results showed a strong perceptual-motor coupling in the task of approaching and stepping up a curb, rendering this task a suitable test for perceptual-motor regulation in walking. Copyright © 2017 Elsevier B.V. All rights reserved.

Dual tasking and stuttering: from the laboratory to the clinic.

PubMed

Metten, Christine; Bosshardt, Hans-Georg; Jones, Mark; Eisenhuth, John; Block, Susan; Carey, Brenda; O'Brian, Sue; Packman, Ann; Onslow, Mark; Menzies, Ross

2011-01-01

The aim of the three studies in this article was to develop a way to include dual tasking in speech restructuring treatment for persons who stutter (PWS). It is thought that this may help clients maintain the benefits of treatment in the real world, where attentional resources are frequently diverted away from controlling fluency by the demands of other tasks. In Part 1, 17 PWS performed a story-telling task and a computer semantic task simultaneously. Part 2 reports the incorporation of the Part 1 protocol into a handy device for use in a clinical setting (the Dual Task and Stuttering Device, DAS-D). Part 3 is a proof of concept study in which three PWS reported on their experiences of using the device during treatment. In Part 1, stuttering frequency and errors on the computer task both increased under dual task conditions, indicating that the protocol would be appropriate for use in a clinical setting. All three participants in Part 3 reported positively on their experiences using the DAS-D. Dual tasking during treatment using the DAS-D appears to be a viable clinical procedure. Further research is required to establish effectiveness.

Validity and Reliability of Gait and Postural Control Analysis Using the Tri-axial Accelerometer of the iPod Touch.

PubMed

Kosse, Nienke M; Caljouw, Simone; Vervoort, Danique; Vuillerme, Nicolas; Lamoth, Claudine J C

2015-08-01

Accelerometer-based assessments can identify elderly with an increased fall risk and monitor interventions. Smart devices, like the iPod Touch, with built-in accelerometers are promising for clinical gait and posture assessments due to easy use and cost-effectiveness. The aim of the present study was to establish the validity and reliability of the iPod Touch for gait and posture assessment. Sixty healthy participants (aged 18-75 years) were measured with an iPod Touch and stand-alone accelerometer while they walked under single- and dual-task conditions, and while standing in parallel and semi-tandem stance with eyes open, eyes closed and when performing a dual task. Cross-correlation values (CCV) showed high correspondence of anterior-posterior and medio-lateral signal patterns (CCV's ≥ 0.88). Validity of gait parameters (foot contacts, index of harmonicity, and amplitude variability) and standing posture parameters [root mean square of accelerations, median power frequency (MPF) and sway area] as indicated by intra-class correlation (ICC) was high (ICC = 0.85-0.99) and test-retest reliability was good (ICC = 0.81-0.97), except for MPF (ICC = 0.59-0.87). Overall, the iPod Touch obtained valid and reliable measures of gait and postural control in healthy adults of all ages under different conditions. Additionally, smart devices have the potential to be used for clinical gait and posture assessments.

Intraindividual Variability in Executive Functions but Not Speed of Processing or Conflict Resolution Predicts Performance Differences in Gait Speed in Older Adults

PubMed Central

Mahoney, Jeannette; Verghese, Joe

2014-01-01

Background. The relationship between executive functions (EF) and gait speed is well established. However, with the exception of dual tasking, the key components of EF that predict differences in gait performance have not been determined. Therefore, the current study was designed to determine whether processing speed, conflict resolution, and intraindividual variability in EF predicted variance in gait performance in single- and dual-task conditions. Methods. Participants were 234 nondemented older adults (mean age 76.48 years; 55% women) enrolled in a community-based cohort study. Gait speed was assessed using an instrumented walkway during single- and dual-task conditions. The flanker task was used to assess EF. Results. Results from the linear mixed effects model showed that (a) dual-task interference caused a significant dual-task cost in gait speed (estimate = 35.99; 95% CI = 33.19–38.80) and (b) of the cognitive predictors, only intraindividual variability was associated with gait speed (estimate = −.606; 95% CI = −1.11 to −.10). In unadjusted analyses, the three EF measures were related to gait speed in single- and dual-task conditions. However, in fully adjusted linear regression analysis, only intraindividual variability predicted performance differences in gait speed during dual tasking (B = −.901; 95% CI = −1.557 to −.245). Conclusion. Among the three EF measures assessed, intraindividual variability but not speed of processing or conflict resolution predicted performance differences in gait speed. PMID:24285744

Neuromechanical considerations for incorporating rhythmic arm movement in the rehabilitation of walking

NASA Astrophysics Data System (ADS)

Klimstra, Marc D.; Thomas, Evan; Stoloff, Rebecca H.; Ferris, Daniel P.; Zehr, E. Paul

2009-06-01

We have extensively used arm cycling to study the neural control of rhythmic movements such as arm swing during walking. Recently rhythmic movement of the arms has also been shown to enhance and shape muscle activity in the legs. However, restricted information is available concerning the conditions necessary to maximally alter lumbar spinal cord excitability. Knowledge on the neuromechanics of a task can assist in the determination of the type, level, and timing of neural signals, yet arm swing during walking and arm cycling have not received a detailed neuromechanical comparison. The purpose of this research was to provide a combined neural and mechanical measurement approach that could be used to assist in the determination of the necessary and sufficient conditions for arm movement to assist in lower limb rehabilitation after stroke and spinal cord injury. Subjects performed three rhythmic arm movement tasks: (1) cycling (cycle); (2) swinging while standing (swing); and (3) swinging while treadmill walking (walk). We hypothesized that any difference in neural control between tasks (i.e., pattern of muscle activity) would reflect changes in the mechanical constraints unique to each task. Three-dimensional kinematics were collected simultaneously with force measurement at the hand and electromyography from the arms and trunk. All data were appropriately segmented to allow a comparison between and across conditions and were normalized and averaged to 100% movement cycle based on shoulder excursion. Separate mathematical principal components analysis of kinematic and neural variables was performed to determine common task features and muscle synergies. The results highlight important neural and mechanical features that distinguish differences between tasks. For example, there are considerable differences in the anatomical positions of the arms during each task, which relate to the moments experienced about the elbow and shoulder. Also, there are differences between tasks in elbow flexion/extension kinematics alongside differential muscle activation profiles. As well, mechanical assistance and constraints during all tasks could affect muscle recruitment and the functional role of muscles. Overall, despite neural and mechanical differences, the results are consistent with conserved common central motor control mechanisms operational for cycle, walk, and swing but appropriately sculpted to demands unique to each task. However, changing the mechanical parameters could affect the role of afferent feedback altering neural control and the coupling to the lower limbs.

Central as well as Peripheral Attentional Bottlenecks in Dual-Task Performance Activate Lateral Prefrontal Cortices

PubMed Central

Szameitat, André J.; Vanloo, Azonya; Müller, Hermann J.

2016-01-01

Human information processing suffers from severe limitations in parallel processing. In particular, when required to respond to two stimuli in rapid succession, processing bottlenecks may appear at central and peripheral stages of task processing. Importantly, it has been suggested that executive functions are needed to resolve the interference arising at such bottlenecks. The aims of the present study were to test whether central attentional limitations (i.e., bottleneck at the decisional response selection stage) as well as peripheral limitations (i.e., bottleneck at response initiation) both demand executive functions located in the lateral prefrontal cortex. For this, we re-analyzed two previous studies, in which a total of 33 participants performed a dual-task according to the paradigm of the psychological refractory period (PRP) during functional magnetic resonance imaging (fMRI). In one study (N = 17), the PRP task consisted of two two-choice response tasks known to suffer from a central bottleneck (CB group). In the other study (N = 16), the PRP task consisted of two simple-response tasks known to suffer from a peripheral bottleneck (PB group). Both groups showed considerable dual-task costs in form of slowing of the second response in the dual-task (PRP effect). Imaging results are based on the subtraction of both single-tasks from the dual-task within each group. In the CB group, the bilateral middle frontal gyri and inferior frontal gyri were activated. Higher activation in these areas was associated with lower dual-task costs. In the PB group, the right middle frontal and inferior frontal gyrus (IFG) were activated. Here, higher activation was associated with higher dual-task costs. In conclusion we suggest that central and peripheral bottlenecks both demand executive functions located in lateral prefrontal cortices (LPFC). Differences between the CB and PB groups with respect to the exact prefrontal areas activated and the correlational patterns suggest that the executive functions resolving interference at least partially differ between the groups. PMID:27014044

The effect of repeated bouts of backward walking on physiologic efficiency.

PubMed

Childs, John D; Gantt, Christy; Higgins, Dan; Papazis, Janet A; Franklin, Ronald; Metzler, Terri; Underwood, Frank B

2002-08-01

Previous studies have demonstrated an increased energy expenditure with novel tasks. With practice, the energy cost decreases as the body more efficiently recruits motor units. This study examined whether one becomes more efficient after repeated bouts of backward walking. The subjects were 7 healthy subjects between the ages of 23 and 49 years. A backward walking speed was calculated to elicit a VO(2) equal to 60% of the VO(2)max. There were 18 training sessions at the prescribed walking speed 3 d x wk(-1) for 20 min x d(-1). The backward walking speed required to elicit a fixed VO(2) increased between weeks 4 and 6 of the training period. This finding suggests that backward walking is indeed a novel task and that motor learning occurs as a result of practice, leading to a more efficient recruitment of motor units.

Stilt walking: how do we learn those first steps?

PubMed

Akram, Sakineh B; Frank, James S

2009-09-01

This study examined how young healthy adults learn stilt walking. Ten healthy male university students attended two sessions of testing held on two consecutive days. In each session participants performed three blocks of 10 stilt-walking trials. Angular movements of head and trunk and the spatial and temporal gait parameters were recorded. When walking on stilts young adults improved their gait velocity through modifications of step parameters while maintaining trunk movements close to that observed during normal over-ground walking. Participants improved their performance by increasing their step frequency and step length and reducing the double support percentage of the gait cycle. Stilts are often used for drywall installation, painting over-the-head areas and raising workers above the ground without the burden of erecting scaffolding. This research examines the locomotor adaptation as young healthy adults learn the complex motor task of stilt walking; a task that is frequently used in the construction industry.

Mind wandering in text comprehension under dual-task conditions.

PubMed

Dixon, Peter; Li, Henry

2013-01-01

In two experiments, subjects responded to on-task probes while reading under dual-task conditions. The secondary task was to monitor the text for occurrences of the letter e. In Experiment 1, reading comprehension was assessed with a multiple-choice recognition test; in Experiment 2, subjects recalled the text. In both experiments, the secondary task replicated the well-known "missing-letter effect" in which detection of e's was less effective for function words and the word "the." Letter detection was also more effective when subjects were on task, but this effect did not interact with the missing-letter effect. Comprehension was assessed in both the dual-task conditions and in control single-task conditions. In the single-task conditions, both recognition (Experiment 1) and recall (Experiment 2) was better when subjects were on task, replicating previous research on mind wandering. Surprisingly, though, comprehension under dual-task conditions only showed an effect of being on task when measured with recall; there was no effect on recognition performance. Our interpretation of this pattern of results is that subjects generate responses to on-task probes on the basis of a retrospective assessment of the contents of working memory. Further, we argue that under dual-task conditions, the contents of working memory is not closely related to the reading processes required for accurate recognition performance. These conclusions have implications for models of text comprehension and for the interpretation of on-task probe responses.

Mind wandering in text comprehension under dual-task conditions

PubMed Central

Dixon, Peter; Li, Henry

2013-01-01

In two experiments, subjects responded to on-task probes while reading under dual-task conditions. The secondary task was to monitor the text for occurrences of the letter e. In Experiment 1, reading comprehension was assessed with a multiple-choice recognition test; in Experiment 2, subjects recalled the text. In both experiments, the secondary task replicated the well-known “missing-letter effect” in which detection of e's was less effective for function words and the word “the.” Letter detection was also more effective when subjects were on task, but this effect did not interact with the missing-letter effect. Comprehension was assessed in both the dual-task conditions and in control single-task conditions. In the single-task conditions, both recognition (Experiment 1) and recall (Experiment 2) was better when subjects were on task, replicating previous research on mind wandering. Surprisingly, though, comprehension under dual-task conditions only showed an effect of being on task when measured with recall; there was no effect on recognition performance. Our interpretation of this pattern of results is that subjects generate responses to on-task probes on the basis of a retrospective assessment of the contents of working memory. Further, we argue that under dual-task conditions, the contents of working memory is not closely related to the reading processes required for accurate recognition performance. These conclusions have implications for models of text comprehension and for the interpretation of on-task probe responses. PMID:24101909

Dual Extended Kalman Filter for the Identification of Time-Varying Human Manual Control Behavior

NASA Technical Reports Server (NTRS)

Popovici, Alexandru; Zaal, Peter M. T.; Pool, Daan M.

2017-01-01

A Dual Extended Kalman Filter was implemented for the identification of time-varying human manual control behavior. Two filters that run concurrently were used, a state filter that estimates the equalization dynamics, and a parameter filter that estimates the neuromuscular parameters and time delay. Time-varying parameters were modeled as a random walk. The filter successfully estimated time-varying human control behavior in both simulated and experimental data. Simple guidelines are proposed for the tuning of the process and measurement covariance matrices and the initial parameter estimates. The tuning was performed on simulation data, and when applied on experimental data, only an increase in measurement process noise power was required in order for the filter to converge and estimate all parameters. A sensitivity analysis to initial parameter estimates showed that the filter is more sensitive to poor initial choices of neuromuscular parameters than equalization parameters, and bad choices for initial parameters can result in divergence, slow convergence, or parameter estimates that do not have a real physical interpretation. The promising results when applied to experimental data, together with its simple tuning and low dimension of the state-space, make the use of the Dual Extended Kalman Filter a viable option for identifying time-varying human control parameters in manual tracking tasks, which could be used in real-time human state monitoring and adaptive human-vehicle haptic interfaces.

Task-set inertia and memory-consolidation bottleneck in dual tasks.

PubMed

Koch, Iring; Rumiati, Raffaella I

2006-11-01

Three dual-task experiments examined the influence of processing a briefly presented visual object for deferred verbal report on performance in an unrelated auditory-manual reaction time (RT) task. RT was increased at short stimulus-onset asynchronies (SOAs) relative to long SOAs, showing that memory consolidation processes can produce a functional processing bottleneck in dual-task performance. In addition, the experiments manipulated the spatial compatibility of the orientation of the visual object and the side of the speeded manual response. This cross-task compatibility produced relative RT benefits only when the instruction for the visual task emphasized overlap at the level of response codes across the task sets (Experiment 1). However, once the effective task set was in place, it continued to produce cross-task compatibility effects even in single-task situations ("ignore" trials in Experiment 2) and when instructions for the visual task did not explicitly require spatial coding of object orientation (Experiment 3). Taken together, the data suggest a considerable degree of task-set inertia in dual-task performance, which is also reinforced by finding costs of switching task sequences (e.g., AC --> BC vs. BC --> BC) in Experiment 3.

Ecological Relevance Determines Task Priority in Older Adults' Multitasking.

PubMed

Doumas, Michail; Krampe, Ralf Th

2015-05-01

Multitasking is a challenging aspect of human behavior, especially if the concurrently performed tasks are different in nature. Several studies demonstrated pronounced performance decrements (dual-task costs) in older adults for combinations of cognitive and motor tasks. However, patterns of costs among component tasks differed across studies and reasons for participants' resource allocation strategies remained elusive. We investigated young and older adults' multitasking of a working memory task and two sensorimotor tasks, one with low (finger force control) and one with high ecological relevance (postural control). The tasks were performed in single-, dual-, and triple-task contexts. Working memory accuracy was reduced in dual-task contexts with either sensorimotor task and deteriorated further under triple-task conditions. Postural and force performance deteriorated with age and task difficulty in dual-task contexts. However, in the triple-task context with its maximum resource demands, older adults prioritized postural control over both force control and memory. Our results identify ecological relevance as the key factor in older adults' multitasking. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Word Frequency Effects in Dual-Task Studies Using Lexical Decision and Naming as Task 2

NASA Technical Reports Server (NTRS)

Remington, Roger W.; McCann, Robert S.; VanSelst, Mark; Shafto, Michael G. (Technical Monitor)

1997-01-01

Word frequency effects in dual-task lexical decision are variously reported to be additive or underadditive across SOA. We replicate and extend earlier lexical decision studies and find word frequency to be additive across SOA. To more directly capture lexical processing, we examine dual-task naming. Once again, we find word frequency to be additive across SOA. Lexical processing appears to be constrained by central processing limitations.

Word Effects in Dual-Task Studies Using Lexical Decision and Naming as Task 2

NASA Technical Reports Server (NTRS)

Remington, Roger; McCann, Robert S.; VanSelst, Mark; Shafto, Michael (Technical Monitor)

1997-01-01

Word frequency effects in dual-task, lexical decision are variously reported to be additive or under-additive across SOA. We replicate and extend earlier lexical decision studies and find word frequency to be additive across SOA. To more directly capture lexical processing, we examine dual-task naming. Once again we find word frequency to be additive across SOA. Lexical processing appears to be constrained by central processing limitations.

The effect of methylphenidate on postural stability under single and dual task conditions in children with attention deficit hyperactivity disorder - a double blind randomized control trial.

PubMed

Jacobi-Polishook, Talia; Shorer, Zamir; Melzer, Itshak

2009-05-15

To investigate the effects of Methylphenidate (MPH) on postural stability in attention deficit hyperactivity disorder (ADHD) children in single and dual task conditions. A randomized controlled double-blind study analyzing postural stability in 24 ADHD children before and after MPH vs. placebo treatments, in three task conditions: (1) Single task, standing still; (2) dual task, standing still performing a memory-attention demanding task; (3) standing still listening to music. MPH resulted in a significant improvement in postural stability during the dual task condition and while listening to music, with no equivalent improvement in placebo controls. MPH improves postural stability in ADHD, especially when an additional task is performed. This is probably due to enhanced attention abilities, thus contributing to improved balance control during performance of tasks that require attention. MPH remains to be studied as a potential drug treatment to improve balance control and physical functioning in other clinical populations.

Effect of Water Immersion on Dual-task Performance: Implications for Aquatic Therapy.

PubMed

Schaefer, Sydney Y; Louder, Talin J; Foster, Shayla; Bressel, Eadric

2016-09-01

Much is known about cardiovascular and biomechanical responses to exercise during water immersion, yet an understanding of the higher-order neural responses to water immersion is unclear. The purpose of this study was to compare cognitive and motor performance between land and water environments using a dual-task paradigm, which served as an indirect measure of cortical processing. A quasi-experimental crossover research design is used. Twenty-two healthy participants (age = 24.3 ± 5.24 years) and a single-case patient (age = 73) with mild cognitive impairment performed a cognitive (auditory vigilance) and motor (standing balance) task separately (single-task condition) and simultaneously (dual-task condition) on land and in chest-deep water. Listening errors from the auditory vigilance task and centre of pressure (CoP) area for the balance task measured cognitive and motor performance, respectively. Listening errors for the single-task and dual-task conditions were 42% and 45% lower for the water than land condition, respectively (effect size [ES] = 0.38 and 0.55). CoP area for the single-task and dual-task conditions, however, were 115% and 164% lower on land than in water, respectively, and were lower (≈8-33%) when balancing concurrently with the auditory vigilance task compared with balancing alone, regardless of environment (ES = 0.23-1.7). This trend was consistent for the single-case patient. Participants tended to make fewer 'cognitive' errors while immersed chest-deep in water than on land. These same participants also tended to display less postural sway under dual-task conditions, but more in water than on land. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Development and Pilot Testing of the Dual Task Screen in Healthy Adolescents.

PubMed

Stephens, Jaclyn; Nicholson, Rachel; Slomine, Beth; Suskauer, Stacy

Athletes with mild traumatic brain injury (mTBI) should refrain from high-risk activities until recovered (symptom free and cognitive and physical exam findings normalize). Studies have suggested that this examination may not be sufficiently sensitive because dual-task paradigms, which typically assess motor performance while a person simultaneously completes a distractor task, can detect residual deficits in athletes who otherwise appear recovered from mTBI. Paradigms used to date are time-intensive procedures conducted in laboratory settings. Here, we report findings from a pilot study of the Dual Task Screen (DTS), which is a brief evaluation with two dual-task paradigms. In 32 healthy female adolescents, the DTS was administered in a mean of 5.63 min in the community, and every participant had poorer dual-condition performance on at least one of the motor tasks. The DTS is a clinically feasible measure and merits additional study regarding utility in adolescents with mTBIs. Copyright © 2018 by the American Occupational Therapy Association, Inc.

Operation Compatibility: A Neglected Contribution to Dual-Task Costs

ERIC Educational Resources Information Center

Pannebakker, Merel M.; Band, Guido P. H.; Ridderinkhof, K. Richard

2009-01-01

Traditionally, dual-task interference has been attributed to the consequences of task load exceeding capacity limitations. However, the current study demonstrates that in addition to task load, the mutual compatibility of the concurrent processes modulates whether 2 tasks can be performed in parallel. In 2 psychological refractory period…

High levels of time contraction in young children in dual tasks are related to their limited attention capacities.

PubMed

Hallez, Quentin; Droit-Volet, Sylvie

2017-09-01

Numerous studies have shown that durations are judged shorter in a dual-task condition than in a simple-task condition. The resource-based theory of time perception suggests that this is due to the processing of temporal information, which is a demanding cognitive task that consumes limited attention resources. Our study investigated whether this time contraction in a dual-task condition is greater in younger children and, if so, whether this is specifically related to their limited attention capacities. Children aged 5-7years were given a temporal reproduction task in a simple-task condition and a dual-task condition. In addition, different neuropsychological tests were used to assess not only their attention capacities but also their capacities in terms of working memory and information processing speed. The results showed a shortening of perceived time in the dual task compared with the simple task, and this increased as age decreased. The extent of this shortening effect was directly linked to younger children's limited attentional capacities; the lower their attentional capacities, the greater the time contraction. This study demonstrated that children's errors in time judgments are linked to their cognitive capacities rather than to capacities that are specific to time. Copyright © 2017 Elsevier Inc. All rights reserved.

The Neurocognitive Basis for Impaired Dual-Task Performance in Senior Fallers.

PubMed

Nagamatsu, Lindsay S; Hsu, C Liang; Voss, Michelle W; Chan, Alison; Bolandzadeh, Niousha; Handy, Todd C; Graf, Peter; Beattie, B Lynn; Liu-Ambrose, Teresa

2016-01-01

Falls are a major health-care concern, and while dual-task performance is widely recognized as being impaired in those at-risk for falls, the underlying neurocognitive mechanisms remain unknown. A better understanding of the underlying mechanisms could lead to the refinement and development of behavioral, cognitive, or neuropharmacological interventions for falls prevention. Therefore, we conducted a cross-sectional study with community-dwelling older adults aged 70-80 years with a history of falls (i.e., two or more falls in the past 12 months) or no history of falls (i.e., zero falls in the past 12 months); n = 28 per group. We compared functional activation during cognitive-based dual-task performance between fallers and non-fallers using functional magnetic resonance imaging (fMRI). Executive cognitive functioning was assessed via Stroop, Trail Making, and Digit Span. Mobility was assessed via the Timed Up and Go test (TUG). We found that non-fallers exhibited significantly greater functional activation compared with fallers during dual-task performance in key regions responsible for resolving dual-task interference, including precentral, postcentral, and lingual gyri. Further, we report slower reaction times during dual-task performance in fallers and significant correlations between level of functional activation and independent measures of executive cognitive functioning and mobility. Our study is the first neuroimaging study to examine dual-task performance in fallers, and supports the notion that fallers have reduced functional brain activation compared with non-fallers. Given that dual-task performance-and the underlying neural concomitants-appears to be malleable with relevant training, our study serves as a launching point for promising strategies to reduce falls in the future.

The Association between Dual-Task Gait after Concussion and Prolonged Symptom Duration.

PubMed

Howell, David R; Brilliant, Anna; Berkstresser, Brant; Wang, Francis; Fraser, Joana; Meehan, William P

2017-12-01

Quantitative gait measurements can identify persistent postconcussion impairments. However, their prognostic utility after injury to identify the likelihood of prolonged concussion symptoms remains unknown. Our objective was to examine if dual-task gait performance measures are independently associated with persistent (> 28 days) concussion symptoms among a sample of athletes. Sixty individuals diagnosed with a sport-related concussion were assessed within 10 days of their injury. Each participant completed a postconcussion symptom scale, an injury history questionnaire, and a single/dual-task gait examination. They were followed until they no longer reported symptoms, and the duration of time required for symptom resolution was calculated. A binary multivariable logistic regression model determined the independent association between dual-task gait and symptom duration (≤ 28 days vs. >28 days) while controlling for the effect of gender, age, symptom severity, injury-to-examination time, and history of concussion. Seventeen (28%) participants reported a symptom duration >28 days. The dual-task cost for average gait speed (-25.9 ± 9.5% vs. -19.8 ± 8.9%; p = 0.027) and cadence (-18.0 ± 2.9% vs. -12.0 ± 7.7%; p = 0.029) was significantly greater among participants who experienced symptoms for >28 days. After adjusting for potential confounding variables, greater dual-task average gait speed costs were independently associated with prolonged symptom duration (aOR = 0.908; 95% CI = 0.835-0.987). Examinations of dual-task gait may provide useful information during multifaceted concussion examinations. Quantitative assessments that simultaneously test multiple domains, such as dual tasks, may be clinically valuable after a concussion to identify those more likely to experience symptoms for >28 days after injury.

Effect of concurrent walking and interlocutor distance on conversational speech intensity and rate in Parkinson's disease.

PubMed

McCaig, Cassandra M; Adams, Scott G; Dykstra, Allyson D; Jog, Mandar

2016-01-01

Previous studies have demonstrated a negative effect of concurrent walking and talking on gait in Parkinson's disease (PD) but there is limited information about the effect of concurrent walking on speech production. The present study examined the effect of sitting, standing, and three concurrent walking tasks (slow, normal, fast) on conversational speech intensity and speech rate in fifteen individuals with hypophonia related to idiopathic Parkinson's disease (PD) and fourteen age-equivalent controls. Interlocuter (talker-to-talker) distance effects and walking speed were also examined. Concurrent walking was found to produce a significant increase in speech intensity, relative to standing and sitting, in both the control and PD groups. Faster walking produced significantly greater speech intensity than slower walking. Concurrent walking had no effect on speech rate. Concurrent walking and talking produced significant reductions in walking speed in both the control and PD groups. In general, the results of the present study indicate that concurrent walking tasks and the speed of concurrent walking can have a significant positive effect on conversational speech intensity. These positive, "energizing" effects need to be given consideration in future attempts to develop a comprehensive model of speech intensity regulation and they may have important implications for the development of new evaluation and treatment procedures for individuals with hypophonia related to PD. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Transfer after Dual n-Back Training Depends on Striatal Activation Change.

PubMed

Salminen, Tiina; Kühn, Simone; Frensch, Peter A; Schubert, Torsten

2016-09-28

The dual n-back working memory (WM) training paradigm (comprising auditory and visual stimuli) has gained much attention since studies have shown widespread transfer effects. By including a multimodal dual-task component, the task is demanding to the human cognitive system. We investigated whether dual n-back training improves general cognitive resources or a task-specific WM updating process in participants. We expected: (1) widespread transfer effects and the recruitment of a common neuronal network by the training and the transfer tasks and (2) narrower transfer results and that a common activation network alone would not produce transfer, but instead an activation focus on the striatum, which is associated with WM updating processes. The training group showed transfer to an untrained dual-modality WM updating task, but not to single-task versions of the training or the transfer task. They also showed diminished neuronal overlap between the training and the transfer task from pretest to posttest and an increase in striatal activation in both tasks. Furthermore, we found an association between the striatal activation increase and behavioral improvement. The control groups showed no transfer and no change in the amount of activation overlap or in striatal activation from pretest to posttest. We conclude that, instead of improving general cognitive resources (which would have required a transfer effect to all transfer tasks and that a frontal activation overlap between the tasks produced transfer), dual n-back training improved a task-specific process: WM updating of stimuli from two modalities. The current study allows for a better understanding of the cognitive and neural effects of working memory (WM) training and transfer. It shows that dual n-back training mainly improves specific processes of WM updating, and this improvement leads to narrow transfer effects to tasks involving the same processes. On a neuronal level this is accompanied by increased neural activation in the striatum that is related to WM updating. The current findings challenge the view that dual n-back training provokes a general boosting of the WM system and of its neural underpinnings located in frontoparietal brain regions. Instead, the findings imply the relevance of task-specific brain regions which are involved in important cognitive processes during training and transfer tasks. Copyright © 2016 the authors 0270-6474/16/3610198-16$15.00/0.

The effects of load carriage and muscle fatigue on lower-extremity joint mechanics.

PubMed

Wang, He; Frame, Jeff; Ozimek, Elicia; Leib, Daniel; Dugan, Eric L

2013-09-01

Military personnel are commonly afflicted by lower-extremity overuse injuries. Load carriage and muscular fatigue are major stressors during military basic training. To examine effects of load carriage and muscular fatigue on lower-extremity joint mechanics during walking. Eighteen men performed the following tasks: unloaded walking, walking with a 32-kg load, fatigued walking with a 32-kg load, and fatigued walking. After the second walking task, muscle fatigue was elicited through a fatiguing protocol consisting of metered step-ups and heel raises with a 16-kg load. Each walking task was performed at 1.67 m x s(-1) for 5 min. Walking movement was tracked by a VICON motion capture system at 120 Hz. Ground reaction forces were collected by a tandem force instrumented treadmill (AMTI) at 2,400 Hz. Lower-extremity joint mechanics were calculated in Visual 3D. There was no interaction between load carriage and fatigue on lower-extremity joint mechanics (p > .05). Both load carriage and fatigue led to pronounced alterations of lower-extremity joint mechanics (p < .05). Load carriage resulted in increases of pelvis anterior tilt, hip and knee flexion at heel contact, and increases of hip, knee, and ankle joint moments and powers during weight acceptance. Muscle fatigue led to decreases of ankle dorsiflexion at heel contact, dorsiflexor moment, and joint power at weight acceptance. In addition, muscle fatigue increased demand for hip extensor moment and power at weight acceptance. Statistically significant changes in lower-extremity joint mechanics during loaded and fatigued walking may expose military personnel to increased risk for overuse injuries.

Neural correlates of dual-task effect on belief-bias syllogistic reasoning: a near-infrared spectroscopy study.

PubMed

Tsujii, Takeo; Watanabe, Shigeru

2009-09-01

Recent dual-process reasoning theories have explained the belief-bias effect, the tendency for human reasoning to be erroneously biased when logical conclusions are incongruent with beliefs about the world, by proposing a belief-based automatic heuristic system and logic-based demanding analytic system. Although these claims are supported by the behavioral finding that high-load secondary tasks enhance the belief-bias effect, the neural correlates of dual-task reasoning remain unknown. The present study therefore examined the relationship between dual-task effect and activity in the inferior frontal cortex (IFC) during belief-bias reasoning by near-infrared spectroscopy (NIRS). Forty-eight subjects participated in this study (MA=23.46 years). They were required to perform congruent and incongruent reasoning trials while responding to high- and low-load secondary tasks. Behavioral analysis showed that the high-load secondary task impaired only incongruent reasoning performance. NIRS analysis found that the high-load secondary task decreased right IFC activity during incongruent trials. Correlation analysis showed that subjects with enhanced right IFC activity could perform better in the incongruent reasoning trials, though subjects for whom right IFC activity was impaired by the secondary task could not maintain better reasoning performance. These findings suggest that the right IFC may be responsible for the dual-task effect in conflicting reasoning processes. When secondary tasks impair right IFC activity, subjects may rely on the automatic heuristic system, which results in belief-bias responses. We therefore offer the first demonstration of neural correlates of dual-task effect on IFC activity in belief-bias reasoning.

FMRI to probe sex-related differences in brain function with multitasking

PubMed Central

Tschernegg, Melanie; Neuper, Christa; Schmidt, Reinhold; Wood, Guilherme; Kronbichler, Martin; Fazekas, Franz; Enzinger, Christian

2017-01-01

Background Although established as a general notion in society, there is no solid scientific foundation for the existence of sex-differences in multitasking. Reaction time and accuracy in dual task conditions have an inverse relationship relative to single task, independently from sex. While a more disseminated network, parallel to decreasing accuracy and reaction time has been demonstrated in dual task fMRI studies, little is known so far whether there exist respective sex-related differences in activation. Methods We subjected 20 women (mean age = 25.45; SD = 5.23) and 20 men (mean age = 27.55; SD = 4.00) to a combined verbal and spatial fMRI paradigm at 3.0T to assess sex-related skills, based on the assumption that generally women better perform in verbal tasks while men do better in spatial tasks. We also obtained behavioral tests for verbal and spatial intelligence, attention, executive functions, and working memory. Results No differences between women and men were observed in behavioral measures of dual-tasking or cognitive performance. Generally, brain activation increased with higher task load, mainly in the bilateral inferior and prefrontal gyri, the anterior cingulum, thalamus, putamen and occipital areas. Comparing sexes, women showed increased activation in the inferior frontal gyrus in the verbal dual-task while men demonstrated increased activation in the precuneus and adjacent visual areas in the spatial task. Conclusion Against the background of equal cognitive and behavioral dual-task performance in both sexes, we provide first evidence for sex-related activation differences in functional networks for verbal and spatial dual-tasking. PMID:28759619

FMRI to probe sex-related differences in brain function with multitasking.

PubMed

Tschernegg, Melanie; Neuper, Christa; Schmidt, Reinhold; Wood, Guilherme; Kronbichler, Martin; Fazekas, Franz; Enzinger, Christian; Koini, Marisa

2017-01-01

Although established as a general notion in society, there is no solid scientific foundation for the existence of sex-differences in multitasking. Reaction time and accuracy in dual task conditions have an inverse relationship relative to single task, independently from sex. While a more disseminated network, parallel to decreasing accuracy and reaction time has been demonstrated in dual task fMRI studies, little is known so far whether there exist respective sex-related differences in activation. We subjected 20 women (mean age = 25.45; SD = 5.23) and 20 men (mean age = 27.55; SD = 4.00) to a combined verbal and spatial fMRI paradigm at 3.0T to assess sex-related skills, based on the assumption that generally women better perform in verbal tasks while men do better in spatial tasks. We also obtained behavioral tests for verbal and spatial intelligence, attention, executive functions, and working memory. No differences between women and men were observed in behavioral measures of dual-tasking or cognitive performance. Generally, brain activation increased with higher task load, mainly in the bilateral inferior and prefrontal gyri, the anterior cingulum, thalamus, putamen and occipital areas. Comparing sexes, women showed increased activation in the inferior frontal gyrus in the verbal dual-task while men demonstrated increased activation in the precuneus and adjacent visual areas in the spatial task. Against the background of equal cognitive and behavioral dual-task performance in both sexes, we provide first evidence for sex-related activation differences in functional networks for verbal and spatial dual-tasking.

Randomized Controlled Trial of a Home-Based Action Observation Intervention to Improve Walking in Parkinson Disease.

PubMed

Jaywant, Abhishek; Ellis, Terry D; Roy, Serge; Lin, Cheng-Chieh; Neargarder, Sandy; Cronin-Golomb, Alice

2016-05-01

To examine the feasibility and efficacy of a home-based gait observation intervention for improving walking in Parkinson disease (PD). Participants were randomly assigned to an intervention or control condition. A baseline walking assessment, a training period at home, and a posttraining assessment were conducted. The laboratory and participants' home and community environments. Nondemented individuals with PD (N=23) experiencing walking difficulty. In the gait observation (intervention) condition, participants viewed videos of healthy and parkinsonian gait. In the landscape observation (control) condition, participants viewed videos of moving water. These tasks were completed daily for 8 days. Spatiotemporal walking variables were assessed using accelerometers in the laboratory (baseline and posttraining assessments) and continuously at home during the training period. Variables included daily activity, walking speed, stride length, stride frequency, leg swing time, and gait asymmetry. Questionnaires including the 39-item Parkinson Disease Questionnaire (PDQ-39) were administered to determine self-reported change in walking, as well as feasibility. At posttraining assessment, only the gait observation group reported significantly improved mobility (PDQ-39). No improvements were seen in accelerometer-derived walking data. Participants found the at-home training tasks and accelerometer feasible to use. Participants found procedures feasible and reported improved mobility, suggesting that observational training holds promise in the rehabilitation of walking in PD. Observational training alone, however, may not be sufficient to enhance walking in PD. A more challenging and adaptive task, and the use of explicit perceptual learning and practice of actions, may be required to effect change. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Electromyographic and biomechanical analysis of step negotiation in Charcot Marie Tooth subjects whose level walk is not impaired.

PubMed

Lencioni, Tiziana; Piscosquito, Giuseppe; Rabuffetti, Marco; Sipio, Enrica Di; Diverio, Manuela; Moroni, Isabella; Padua, Luca; Pagliano, Emanuela; Schenone, Angelo; Pareyson, Davide; Ferrarin, Maurizio

2018-05-01

Charcot-Marie-Tooth (CMT) is a slowly progressive disease characterized by muscular weakness and wasting with a length-dependent pattern. Mildly affected CMT subjects showed slight alteration of walking compared to healthy subjects (HS). To investigate the biomechanics of step negotiation, a task that requires greater muscle strength and balance control compared to level walking, in CMT subjects without primary locomotor deficits (foot drop and push off deficit) during walking. We collected data (kinematic, kinetic, and surface electromyographic) during walking on level ground and step negotiation, from 98 CMT subjects with mild-to-moderate impairment. Twenty-one CMT subjects (CMT-NLW, normal-like-walkers) were selected for analysis, as they showed values of normalized ROM during swing and produced work at push-off at ankle joint comparable to those of 31 HS. Step negotiation tasks consisted in climbing and descending a two-step stair. Only the first step provided the ground reaction force data. To assess muscle activity, each EMG profile was integrated over 100% of task duration and the activation percentage was computed in four phases that constitute the step negotiation tasks. In both tasks, CMT-NLW showed distal muscle hypoactivation. In addition, during step-ascending CMT-NLW subjects had relevant lower activities of vastus medialis and rectus femoris than HS in weight-acceptance, and, on the opposite, a greater activation as compared to HS in forward-continuance. During step-descending, CMT-NLW showed a reduced activity of tibialis anterior during controlled-lowering phase. Step negotiation revealed adaptive motor strategies related to muscle weakness due to disease in CMT subjects without any clinically apparent locomotor deficit during level walking. In addition, this study provided results useful for tailored rehabilitation of CMT patients. Copyright © 2018 Elsevier B.V. All rights reserved.

Better dual-task processing in simultaneous interpreters

PubMed Central

Strobach, Tilo; Becker, Maxi; Schubert, Torsten; Kühn, Simone

2015-01-01

Simultaneous interpreting (SI) is a highly complex activity and requires the performance and coordination of multiple, simultaneous tasks: analysis and understanding of the discourse in a first language, reformulating linguistic material, storing of intermediate processing steps, and language production in a second language among others. It is, however, an open issue whether persons with experience in SI possess superior skills in coordination of multiple tasks and whether they are able to transfer these skills to lab-based dual-task situations. Within the present study, we set out to explore whether interpreting experience is associated with related higher-order executive functioning in the context of dual-task situations of the Psychological Refractory Period (PRP) type. In this PRP situation, we found faster reactions times in participants with experience in simultaneous interpretation in contrast to control participants without such experience. Thus, simultaneous interpreters possess superior skills in coordination of multiple tasks in lab-based dual-task situations. PMID:26528232

Demands on Finite Cognitive Capacity Cause Infants' Perseverative Errors

ERIC Educational Resources Information Center

Berger, Sarah E.

2004-01-01

This research unites traditionally disparate developmental domains--cognition and locomotion--to examine the classic cognitive issue of the development of inhibition in infancy. In 2 locomotor A-not-B tasks, 13-month-old walking infants inhibited a prepotent response under low task demands (walking on flat ground), but perseverated under increased…

A dual-docking microfluidic cell migration assay (D2-Chip) for testing neutrophil chemotaxis and the memory effect.

PubMed

Yang, Ke; Wu, Jiandong; Xu, Guoqing; Xie, Dongxue; Peretz-Soroka, Hagit; Santos, Susy; Alexander, Murray; Zhu, Ling; Zhang, Michael; Liu, Yong; Lin, Francis

2017-04-18

Chemotaxis is a classic mechanism for guiding cell migration and an important topic in both fundamental cell biology and health sciences. Neutrophils are a widely used model to study eukaryotic cell migration and neutrophil chemotaxis itself can lead to protective or harmful immune actions to the body. While much has been learnt from past research about how neutrophils effectively navigate through a chemoattractant gradient, many interesting questions remain unclear. For example, while it is tempting to model neutrophil chemotaxis using the well-established biased random walk theory, the experimental proof was challenged by the cell's highly persistent migrating nature. A special experimental design is required to test the key predictions from the random walk model. Another question that has interested the cell migration community for decades concerns the existence of chemotactic memory and its underlying mechanism. Although chemotactic memory has been suggested in various studies, a clear quantitative experimental demonstration will improve our understanding of the migratory memory effect. Motivated by these questions, we developed a microfluidic cell migration assay (so-called dual-docking chip or D 2 -Chip) that can test both the biased random walk model and the memory effect for neutrophil chemotaxis on a single chip enabled by multi-region gradient generation and dual-region cell alignment. Our results provide experimental support for the biased random walk model and chemotactic memory for neutrophil chemotaxis. Quantitative data analyses provide new insights into neutrophil chemotaxis and memory by making connections to entropic disorder, cell morphology and oscillating migratory response.

Mean first passage time for random walk on dual structure of dendrimer

NASA Astrophysics Data System (ADS)

Li, Ling; Guan, Jihong; Zhou, Shuigeng

2014-12-01

The random walk approach has recently been widely employed to study the relations between the underlying structure and dynamic of complex systems. The mean first-passage time (MFPT) for random walks is a key index to evaluate the transport efficiency in a given system. In this paper we study analytically the MFPT in a dual structure of dendrimer network, Husimi cactus, which has different application background and different structure (contains loops) from dendrimer. By making use of the iterative construction, we explicitly determine both the partial mean first-passage time (PMFT, the average of MFPTs to a given target) and the global mean first-passage time (GMFT, the average of MFPTs over all couples of nodes) on Husimi cactus. The obtained closed-form results show that PMFPT and EMFPT follow different scaling with the network order, suggesting that the target location has essential influence on the transport efficiency. Finally, the impact that loop structure could bring is analyzed and discussed.

Improvements in Obstacle Clearance Parameters and Reaction Time Over a Series of Obstacles Revealed After Five Repeated Testing Sessions in Older Adults.

PubMed

Jehu, Deborah A; Lajoie, Yves; Paquet, Nicole

2017-12-21

The purpose of this study was to investigate obstacle clearance and reaction time parameters when crossing a series of six obstacles in older adults. A second aim was to examine the repeated exposure of this testing protocol once per week for 5 weeks. In total, 10 older adults (five females; age: 67.0 ± 6.9 years) walked onto and over six obstacles of varying heights (range: 100-200 mm) while completing no reaction time, simple reaction time, and choice reaction time tasks once per week for 5 weeks. The highest obstacles elicited the lowest toe clearance, and the first three obstacles revealed smaller heel clearance compared with the last three obstacles. Dual tasking negatively impacted obstacle clearance parameters when information processing demands were high. Longer and less consistent time to completion was observed in Session 1 compared with Sessions 2-5. Finally, improvements in simple reaction time were displayed after Session 2, but choice reaction time gradually improved and did not reach a plateau after repeated testing.

Shared and task-specific muscle synergies of Nordic walking and conventional walking.

PubMed

Boccia, G; Zoppirolli, C; Bortolan, L; Schena, F; Pellegrini, B

2018-03-01

Nordic walking is a form of walking that includes a poling action, and therefore an additional subtask, with respect to conventional walking. The aim of this study was to assess whether Nordic walking required a task-specific muscle coordination with respect to conventional walking. We compared the electromyographic (EMG) activity of 15 upper- and lower-limb muscles of 9 Nordic walking instructors, while executing Nordic walking and conventional walking at 1.3 ms -1 on a treadmill. Non-negative matrix factorization method was applied to identify muscle synergies, representing the spatial and temporal organization of muscle coordination. The number of muscle synergies was not different between Nordic walking (5.2 ± 0.4) and conventional walking (5.0 ± 0.7, P = .423). Five muscle synergies accounted for 91.2 ± 1.1% and 92.9 ± 1.2% of total EMG variance in Nordic walking and conventional walking, respectively. Similarity and cross-reconstruction analyses showed that 4 muscle synergies, mainly involving lower-limb and trunk muscles, are shared between Nordic walking and conventional walking. One synergy acting during upper limb propulsion is specific to Nordic walking, modifying the spatial organization and the magnitude of activation of upper limb muscles compared to conventional walking. The inclusion of the poling action in Nordic walking does not increase the complexity of movement control and does not change the coordination of lower limb muscles. This makes Nordic walking a physical activity suitable also for people with low motor skill. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Attentional Modulation of Word Recognition by Children in a Dual-Task Paradigm

ERIC Educational Resources Information Center

Choi, Sangsook; Lotto, Andrew; Lewis, Dawna; Hoover, Brenda; Stelmachowicz, Patricia

2008-01-01

Purpose: This study investigated an account of limited short-term memory capacity for children's speech perception in noise using a dual-task paradigm. Method: Sixty-four normal-hearing children (7-14 years of age) participated in this study. Dual tasks were repeating monosyllabic words presented in noise at 8 dB signal-to-noise ratio and…

Measures of static postural control moderate the association of strength and power with functional dynamic balance.

PubMed

Forte, Roberta; Boreham, Colin A G; De Vito, Giuseppe; Ditroilo, Massimiliano; Pesce, Caterina

2014-12-01

Age-related reductions in strength and power are considered to negatively impact balance control, but the existence of a direct association is still an issue of debate. This is possibly due to the fact that balance assessment is complex, reflects different underlying physiologic mechanisms and involves quantitative measurements of postural sway or timing of performance during balance tasks. The present study evaluated the moderator effect of static postural control on the association of power and strength with dynamic balance tasks. Fifty-seven healthy 65-75 year old individuals performed tests of dynamic functional balance (walking speed under different conditions) and of strength, power and static postural control. Dynamic balance performance (walking speed) was associated with lower limb strength and power, as well as postural control under conditions requiring postural adjustments (narrow surface walking r(2) = 0.31, p < 0.001). An interaction effect between strength and static postural control was found with narrow surface walking and talking while walking (change of β 0.980, p < 0.001 in strength for 1 SD improvements in static postural control for narrow walking, and [Formula: see text] -0.730, p < 0.01 in talking while walking). These results indicate that good static postural control facilitates the utilisation of lower limb strength to better perform complex, dynamic functional balance tasks. Practical implications for assessment and training are discussed.

Tai Chi practitioners have better postural control and selective attention in stepping down with and without a concurrent auditory response task.

PubMed

Lu, Xi; Siu, Ka-Chun; Fu, Siu N; Hui-Chan, Christina W Y; Tsang, William W N

2013-08-01

To compare the performance of older experienced Tai Chi practitioners and healthy controls in dual-task versus single-task paradigms, namely stepping down with and without performing an auditory response task, a cross-sectional study was conducted in the Center for East-meets-West in Rehabilitation Sciences at The Hong Kong Polytechnic University, Hong Kong. Twenty-eight Tai Chi practitioners (73.6 ± 4.2 years) and 30 healthy control subjects (72.4 ± 6.1 years) were recruited. Participants were asked to step down from a 19-cm-high platform and maintain a single-leg stance for 10 s with and without a concurrent cognitive task. The cognitive task was an auditory Stroop test in which the participants were required to respond to different tones of voices regardless of their word meanings. Postural stability after stepping down under single- and dual-task paradigms, in terms of excursion of the subject's center of pressure (COP) and cognitive performance, was measured for comparison between the two groups. Our findings demonstrated significant between-group differences in more outcome measures during dual-task than single-task performance. Thus, the auditory Stroop test showed that Tai Chi practitioners achieved not only significantly less error rate in single-task, but also significantly faster reaction time in dual-task, when compared with healthy controls similar in age and other relevant demographics. Similarly, the stepping-down task showed that Tai Chi practitioners not only displayed significantly less COP sway area in single-task, but also significantly less COP sway path than healthy controls in dual-task. These results showed that Tai Chi practitioners achieved better postural stability after stepping down as well as better performance in auditory response task than healthy controls. The improved performance that was magnified by dual motor-cognitive task performance may point to the benefits of Tai Chi being a mind-and-body exercise.

Cognitive demand of human sensorimotor performance during an extended space mission: a dual-task study.

PubMed

Bock, Otmar; Weigelt, Cornelia; Bloomberg, Jacob J

2010-09-01

Two previous single-case studies found that the dual-task costs of manual tracking plus memory search increased during a space mission, and concluded that sensorimotor deficits during spaceflight may be related to cognitive overload. Since dual-task costs were insensitive to the difficulty of memory search, the authors argued that the overload may reflect stress-related problems of multitasking, rather than a scarcity of specific cognitive resources. Here we expand the available database and compare different types of concurrent task. Three subjects were repeatedly tested before, during, and after an extended mission on the International Space Station (ISS). They performed an unstable tracking task and four reaction-time tasks, both separately and concurrently. Inflight data could only be obtained during later parts of the mission. The tracking error increased from pre- to in flight by a factor of about 2, both under single- and dual-task conditions. The dual-task costs with a reaction-time task requiring rhythm production was 2.4 times higher than with a reaction-time task requiring visuo-spatial transformations, and 8 times higher than with a regular choice reaction-time task. Long-term sensorimotor deficits during spaceflight may reflect not only stress, but also a scarcity of resources related to complex motor programming; possibly those resources are tied up by sensorimotor adaptation to the space environment.

Limited Transfer of Newly Acquired Movement Patterns across Walking and Running in Humans

PubMed Central

Ogawa, Tetsuya; Kawashima, Noritaka; Ogata, Toru; Nakazawa, Kimitaka

2012-01-01

The two major modes of locomotion in humans, walking and running, may be regarded as a function of different speed (walking as slower and running as faster). Recent results using motor learning tasks in humans, as well as more direct evidence from animal models, advocate for independence in the neural control mechanisms underlying different locomotion tasks. In the current study, we investigated the possible independence of the neural mechanisms underlying human walking and running. Subjects were tested on a split-belt treadmill and adapted to walking or running on an asymmetrically driven treadmill surface. Despite the acquisition of asymmetrical movement patterns in the respective modes, the emergence of asymmetrical movement patterns in the subsequent trials was evident only within the same modes (walking after learning to walk and running after learning to run) and only partial in the opposite modes (walking after learning to run and running after learning to walk) (thus transferred only limitedly across the modes). Further, the storage of the acquired movement pattern in each mode was maintained independently of the opposite mode. Combined, these results provide indirect evidence for independence in the neural control mechanisms underlying the two locomotive modes. PMID:23029490

The effect of processing code, response modality and task difficulty on dual task performance and subjective workload in a manual system

NASA Technical Reports Server (NTRS)

Liu, Yili; Wickens, Christopher D.

1987-01-01

This paper reports on the first experiment of a series studying the effect of task structure and difficulty demand on time-sharing performance and workload in both automated and corresponding manual systems. The experimental task involves manual control time-shared with spatial and verbal decisions tasks of two levels of difficulty and two modes of response (voice or manual). The results provide strong evidence that tasks and processes competing for common processing resources are time shared less effecively and have higher workload than tasks competing for separate resources. Subjective measures and the structure of multiple resources are used in conjunction to predict dual task performance. The evidence comes from both single-task and from dual-task performance.

Executive Function and Falls in Older Adults: New Findings from a Five-Year Prospective Study Link Fall Risk to Cognition

PubMed Central

Mirelman, Anat; Herman, Talia; Brozgol, Marina; Dorfman, Moran; Sprecher, Elliot; Schweiger, Avraham; Giladi, Nir; Hausdorff, Jeffrey M.

2012-01-01

Background Recent findings suggest that executive function (EF) plays a critical role in the regulation of gait in older adults, especially under complex and challenging conditions, and that EF deficits may, therefore, contribute to fall risk. The objective of this study was to evaluate if reduced EF is a risk factor for future falls over the course of 5 years of follow-up. Secondary objectives were to assess whether single and dual task walking abilities, an alternative window into EF, were associated with fall risk. Methodology/Main Results We longitudinally followed 256 community-living older adults (age: 76.4±4.5 yrs; 61% women) who were dementia free and had good mobility upon entrance into the study. At baseline, a computerized cognitive battery generated an index of EF, attention, a closely related construct, and other cognitive domains. Gait was assessed during single and dual task conditions. Falls data were collected prospectively using monthly calendars. Negative binomial regression quantified risk ratios (RR). After adjusting for age, gender and the number of falls in the year prior to the study, only the EF index (RR: .85; CI: .74–.98, p = .021), the attention index (RR: .84; CI: .75–.94, p = .002) and dual tasking gait variability (RR: 1.11; CI: 1.01–1.23; p = .027) were associated with future fall risk. Other cognitive function measures were not related to falls. Survival analyses indicated that subjects with the lowest EF scores were more likely to fall sooner and more likely to experience multiple falls during the 66 months of follow-up (p<0.02). Conclusions/Significance These findings demonstrate that among community-living older adults, the risk of future falls was predicted by performance on EF and attention tests conducted 5 years earlier. The present results link falls among older adults to cognition, indicating that screening EF will likely enhance fall risk assessment, and that treatment of EF may reduce fall risk. PMID:22768271

Dual-Task Assessment Protocols in Concussion Assessment: A Systematic Literature Review.

PubMed

Kleiner, Michelle; Wong, Lynne; Dubé, Alexandra; Wnuk, Katie; Hunter, Susan W; Graham, Laura J

2018-02-01

Study Design Systematic review. Background When assessed in isolation, balance and neurocognitive testing may not be sufficiently responsive to capture changes that occur with concussion. Normal daily activities require simultaneous cognitive and physical demands. Therefore, a dual-task assessment paradigm should be considered to identify performance deficits. Objectives To evaluate the literature and to identify dual-task testing protocols associated with changes in gait after concussion. Methods A systematic review of articles of individuals with concussion who underwent dual-task testing with a combination of motor and cognitive tasks was conducted. The AMED, CINAHL, Embase, PsycINFO, PubMed, Scopus, SPORTDiscus, and Web of Science databases and gray literature were searched from inception to January 29, 2017. Title and abstract, full-text, and quality review and data abstraction were performed by 2 independent reviewers. Results Twenty-four articles met the inclusion criteria. Eleven articles reported decreased gait velocity and increased medial-lateral displacement for individuals with concussion during dual-task conditions. Overall, included articles were of poor to moderate methodological quality. Fifteen articles used the same participants and data sets, creating a threat to validity and limiting the ability to make conclusions. Conclusion A deterioration in gait performance during dual-task testing is present among people with concussion. Specific recommendations for the use of a dual-task protocol to assess individuals with suspected concussion injury in a clinical setting have yet to be determined. J Orthop Sports Phys Ther 2018;48(2):87-103. Epub 7 Nov 2017. doi:10.2519/jospt.2018.7432.

Intraindividual variability in executive functions but not speed of processing or conflict resolution predicts performance differences in gait speed in older adults.

PubMed

Holtzer, Roee; Mahoney, Jeannette; Verghese, Joe

2014-08-01

The relationship between executive functions (EF) and gait speed is well established. However, with the exception of dual tasking, the key components of EF that predict differences in gait performance have not been determined. Therefore, the current study was designed to determine whether processing speed, conflict resolution, and intraindividual variability in EF predicted variance in gait performance in single- and dual-task conditions. Participants were 234 nondemented older adults (mean age 76.48 years; 55% women) enrolled in a community-based cohort study. Gait speed was assessed using an instrumented walkway during single- and dual-task conditions. The flanker task was used to assess EF. Results from the linear mixed effects model showed that (a) dual-task interference caused a significant dual-task cost in gait speed (estimate = 35.99; 95% CI = 33.19-38.80) and (b) of the cognitive predictors, only intraindividual variability was associated with gait speed (estimate = -.606; 95% CI = -1.11 to -.10). In unadjusted analyses, the three EF measures were related to gait speed in single- and dual-task conditions. However, in fully adjusted linear regression analysis, only intraindividual variability predicted performance differences in gait speed during dual tasking (B = -.901; 95% CI = -1.557 to -.245). Among the three EF measures assessed, intraindividual variability but not speed of processing or conflict resolution predicted performance differences in gait speed. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Tibiofemoral contact forces during walking, running and sidestepping.

PubMed

Saxby, David J; Modenese, Luca; Bryant, Adam L; Gerus, Pauline; Killen, Bryce; Fortin, Karine; Wrigley, Tim V; Bennell, Kim L; Cicuttini, Flavia M; Lloyd, David G

2016-09-01

We explored the tibiofemoral contact forces and the relative contributions of muscles and external loads to those contact forces during various gait tasks. Second, we assessed the relationships between external gait measures and contact forces. A calibrated electromyography-driven neuromusculoskeletal model estimated the tibiofemoral contact forces during walking (1.44±0.22ms(-1)), running (4.38±0.42ms(-1)) and sidestepping (3.58±0.50ms(-1)) in healthy adults (n=60, 27.3±5.4years, 1.75±0.11m, and 69.8±14.0kg). Contact forces increased from walking (∼1-2.8 BW) to running (∼3-8 BW), sidestepping had largest maximum total (8.47±1.57 BW) and lateral contact forces (4.3±1.05 BW), while running had largest maximum medial contact forces (5.1±0.95 BW). Relative muscle contributions increased across gait tasks (up to 80-90% of medial contact forces), and peaked during running for lateral contact forces (∼90%). Knee adduction moment (KAM) had weak relationships with tibiofemoral contact forces (all R(2)<0.36) and the relationships were gait task-specific. Step-wise regression of multiple external gait measures strengthened relationships (0.20

Working Memory Capacity and Resistance to Interference

ERIC Educational Resources Information Center

Oberauer, Klaus; Lange, Elke; Engle, Randall W.

2004-01-01

Single-task and dual-task versions of verbal and spatial serial order memory tasks were administered to 120 students tested for working memory capacity with four previously validated measures. In the dual-task versions, similarity between the memory material and the material of the secondary processing task was varied. With verbal material, three…

Quantum Walks on the Line with Phase Parameters

NASA Astrophysics Data System (ADS)

Villagra, Marcos; Nakanishi, Masaki; Yamashita, Shigeru; Nakashima, Yasuhiko

In this paper, a study on discrete-time coined quantum walks on the line is presented. Clear mathematical foundations are still lacking for this quantum walk model. As a step toward this objective, the following question is being addressed: Given a graph, what is the probability that a quantum walk arrives at a given vertex after some number of steps? This is a very natural question, and for random walks it can be answered by several different combinatorial arguments. For quantum walks this is a highly non-trivial task. Furthermore, this was only achieved before for one specific coin operator (Hadamard operator) for walks on the line. Even considering only walks on lines, generalizing these computations to a general SU(2) coin operator is a complex task. The main contribution is a closed-form formula for the amplitudes of the state of the walk (which includes the question above) for a general symmetric SU(2) operator for walks on the line. To this end, a coin operator with parameters that alters the phase of the state of the walk is defined. Then, closed-form solutions are computed by means of Fourier analysis and asymptotic approximation methods. We also present some basic properties of the walk which can be deducted using weak convergence theorems for quantum walks. In particular, the support of the induced probability distribution of the walk is calculated. Then, it is shown how changing the parameters in the coin operator affects the resulting probability distribution.

Reliability and validity of a dual-task test for skill proficiency in roundhouse kicks in elite taekwondo athletes.

PubMed

Chen, Chung-Yu; Dai, Jing; Chen, I-Fan; Chou, Kuei-Ming; Chang, Chen-Kang

2015-01-01

The dual-task methodology, conducting two tasks simultaneously, may provide better validity than the traditional single-task tests in the environment that is closely related to real sport competitions. The purpose of this study is to determine the reliability and validity of a dual-task test that aims to measure the reaction time and skill proficiency in roundhouse kicks in elite and sub-elite taekwondo athletes. The dual-task results were compared to those in the single-task movements with various levels of complexity. The single-task movements A, B, and C were composed of one, three, and five roundhouse kicks, respectively. The dual-task movement D was composed of movement C and a push of a button in response to a light stimulus as the secondary task. The subjects were 12 elite and 12 sub-elite male taekwondo athletes. The test included four movements with five repeats of each movement in a randomized order. Each subject conducted the same test on two consecutive days. The intraclass correlation coefficient (ICC) showed moderate-to-high correlation in the premotor time (ICC =0.439-0.634 in elite and ICC =0.681-0.824 in sub-elite), motor time (ICC =0.861-0.956 in elite and ICC =0.721-0.931 in sub-elite), and reaction time (ICC =0.692 in elite and ICC =0.676 in sub-elite) in the secondary task in both groups. The elite athletes had significantly faster premotor time than their sub-elite counterparts in all the four movements (all P<0.05). The largest difference lies in the reaction time in the secondary task, in which the elite group (0.248±0.026 seconds) was 33.0% faster than the sub-elite group (0.370±0.081 seconds) (P<0.001). This study shows that the test developed in this study has reasonable reliability and validity in both single- and dual-task methods. In addition, the dual-task method may be a more appropriate way to assess the reaction time and skill proficiency in taekwondo athletes.

Reliability and validity of a dual-task test for skill proficiency in roundhouse kicks in elite taekwondo athletes

PubMed Central

Chen, Chung-Yu; Dai, Jing; Chen, I-Fan; Chou, Kuei-Ming; Chang, Chen-Kang

2015-01-01

The dual-task methodology, conducting two tasks simultaneously, may provide better validity than the traditional single-task tests in the environment that is closely related to real sport competitions. The purpose of this study is to determine the reliability and validity of a dual-task test that aims to measure the reaction time and skill proficiency in roundhouse kicks in elite and sub-elite taekwondo athletes. The dual-task results were compared to those in the single-task movements with various levels of complexity. The single-task movements A, B, and C were composed of one, three, and five roundhouse kicks, respectively. The dual-task movement D was composed of movement C and a push of a button in response to a light stimulus as the secondary task. The subjects were 12 elite and 12 sub-elite male taekwondo athletes. The test included four movements with five repeats of each movement in a randomized order. Each subject conducted the same test on two consecutive days. The intraclass correlation coefficient (ICC) showed moderate-to-high correlation in the premotor time (ICC =0.439–0.634 in elite and ICC =0.681–0.824 in sub-elite), motor time (ICC =0.861–0.956 in elite and ICC =0.721–0.931 in sub-elite), and reaction time (ICC =0.692 in elite and ICC =0.676 in sub-elite) in the secondary task in both groups. The elite athletes had significantly faster premotor time than their sub-elite counterparts in all the four movements (all P<0.05). The largest difference lies in the reaction time in the secondary task, in which the elite group (0.248±0.026 seconds) was 33.0% faster than the sub-elite group (0.370±0.081 seconds) (P<0.001). This study shows that the test developed in this study has reasonable reliability and validity in both single- and dual-task methods. In addition, the dual-task method may be a more appropriate way to assess the reaction time and skill proficiency in taekwondo athletes. PMID:26150736

To speak or not to speak - A multiple resource perspective

NASA Technical Reports Server (NTRS)

Tsang, P. S.; Hartzell, E. J.; Rothschild, R. A.

1985-01-01

The desirability of employing speech response in a dynamic dual task situation was discussed from a multiple resource perspective. A secondary task technique was employed to examine the time-sharing performance of five dual tasks with various degrees of resource overlap according to the structure-specific resource model of Wickens (1980). The primary task was a visual/manual tracking task which required spatial processing. The secondary task was either another tracking task or a spatial transformation task with one of four input (visual or auditory) and output (manual or speech) configurations. The results show that the dual task performance was best when the primary tracking task was paired with the visual/speech transformation task. This finding was explained by an interaction of the stimulus-central processing-response compatibility of the transformation task and the degree of resource competition between the time-shared tasks. Implications on the utility of speech response were discussed.

Dual-task as a predictor of falls in older people with mild cognitive impairment and mild Alzheimer's disease: a prospective cohort study.

PubMed

Gonçalves, Jessica; Ansai, Juliana Hotta; Masse, Fernando Arturo Arriagada; Vale, Francisco Assis Carvalho; Takahashi, Anielle Cristhine de Medeiros; Andrade, Larissa Pires de

2018-04-04

A dual-task tool with a challenging and daily secondary task, which involves executive functions, could facilitate the screening for risk of falls in older people with mild cognitive impairment or mild Alzheimer's disease. To verify if a motor-cognitive dual-task test could predict falls in older people with mild cognitive impairment or mild Alzheimer's disease, and to establish cutoff scores for the tool for both groups. A prospective study was conducted with community-dwelling older adults, including 40 with mild cognitive impairment and 38 with mild Alzheimer's disease. The dual-task test consisted of the Timed up and Go Test associated with a motor-cognitive task using a phone to call. Falls were recorded during six months by calendar and monthly telephone calls and the participants were categorized as fallers or non-fallers. In the Mild cognitive impairment Group, fallers presented higher values in time (35.2s), number of steps (33.7 steps) and motor task cost (116%) on dual-task compared to non-fallers. Time, number of steps and motor task cost were significantly associated with falls in people with mild cognitive impairment. Multivariate analysis identified higher number of steps spent on the test to be independently associated with falls. A time greater than 23.88s (sensitivity=80%; specificity=61%) and a number of steps over 29.50 (sensitivity=65%; specificity=83%) indicated prediction of risk of falls in the Mild cognitive impairment Group. Among people with Alzheimer's disease, no differences in dual-task between fallers and non-fallers were found and no variable of the tool was able to predict falls. The dual-task predicts falls only in older people with mild cognitive impairment. Copyright © 2018 Associação Brasileira de Pesquisa e Pós-Graduação em Fisioterapia. Publicado por Elsevier Editora Ltda. All rights reserved.

Mood states determine the degree of task shielding in dual-task performance.

PubMed

Zwosta, Katharina; Hommel, Bernhard; Goschke, Thomas; Fischer, Rico

2013-01-01

Current models of multitasking assume that dual-task performance and the degree of multitasking are affected by cognitive control strategies. In particular, cognitive control is assumed to regulate the amount of shielding of the prioritised task from crosstalk from the secondary task. We investigated whether and how task shielding is influenced by mood states. Participants were exposed to two short film clips, one inducing high and one inducing low arousal, of either negative or positive content. Negative mood led to stronger shielding of the prioritised task (i.e., less crosstalk) than positive mood, irrespective of arousal. These findings support the assumption that emotional states determine the parameters of cognitive control and play an important role in regulating dual-task performance.

Evaluation of the walkable neighborhoods for seniors project in Sacramento County.

PubMed

Hooker, Steven P; Cirill, Lisa A; Geraghty, Anne

2009-07-01

The Walkable Neighborhoods for Seniors project was implemented to foster the creation and promotion of safe and accessible neighborhood walking routes for seniors. This article describes a case study of the efforts put forth by a local task force jointly managed by the Sacramento County Department of Health Services and WALK Sacramento. To facilitate environmental and policy changes that would enable and encourage walking by older adults, these local lead agencies implemented several strategies including organizing a community task force with broad professional and civic representation, conducting environmental audits of selected walking routes, creating walking groups, and advocating for environmental and policy change. Evaluation processes yield information on successes, challenges, and lessons learned that could be applied to similar efforts undertaken by community organizations to improve the walkability of neighborhoods for older adults.

Dynamic and functional balance tasks in subjects with persistent whiplash: a pilot trial.

PubMed

Stokell, Raina; Yu, Annie; Williams, Katrina; Treleaven, Julia

2011-08-01

Disturbances in static balance have been demonstrated in subjects with persistent whiplash. Some also report loss of balance and falls. These disturbances may contribute to difficulties in dynamic tasks. The aim of this study was to determine whether subjects with whiplash had deficits in dynamic and functional balance tasks when compared to a healthy control group. Twenty subjects with persistent pain following a whiplash injury and twenty healthy controls were assessed in single leg stance with eyes open and closed, the step test, Fukuda stepping test, tandem walk on a firm and soft surface, Singleton test with eyes open and closed, a stair walking test and the timed 10 m walk with and without head movement. Subjects with whiplash demonstrated significant deficits (p < 0.01) in single leg stance with eyes closed, the step test, tandem walk on a firm and soft surface, stair walking and the timed 10 m walk with and without head movement when compared to the control subjects. Specific assessment and rehabilitation directed towards improving these deficits may need to be considered in the management of patients with persistent whiplash if these results are confirmed in a larger cohort. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Audition and vision share spatial attentional resources, yet attentional load does not disrupt audiovisual integration.

PubMed

Wahn, Basil; König, Peter

2015-01-01

Humans continuously receive and integrate information from several sensory modalities. However, attentional resources limit the amount of information that can be processed. It is not yet clear how attentional resources and multisensory processing are interrelated. Specifically, the following questions arise: (1) Are there distinct spatial attentional resources for each sensory modality? and (2) Does attentional load affect multisensory integration? We investigated these questions using a dual task paradigm: participants performed two spatial tasks (a multiple object tracking task and a localization task), either separately (single task condition) or simultaneously (dual task condition). In the multiple object tracking task, participants visually tracked a small subset of several randomly moving objects. In the localization task, participants received either visual, auditory, or redundant visual and auditory location cues. In the dual task condition, we found a substantial decrease in participants' performance relative to the results of the single task condition. Importantly, participants performed equally well in the dual task condition regardless of the location cues' modality. This result suggests that having spatial information coming from different modalities does not facilitate performance, thereby indicating shared spatial attentional resources for the auditory and visual modality. Furthermore, we found that participants integrated redundant multisensory information similarly even when they experienced additional attentional load in the dual task condition. Overall, findings suggest that (1) visual and auditory spatial attentional resources are shared and that (2) audiovisual integration of spatial information occurs in an pre-attentive processing stage.

Increased alertness, better than posture prioritization, explains dual-task performance in prosthesis users and controls under increasing postural and cognitive challenge.

PubMed

Howard, Charla L; Perry, Bonnie; Chow, John W; Wallace, Chris; Stokic, Dobrivoje S

2017-11-01

Sensorimotor impairments after limb amputation impose a threat to stability. Commonly described strategies for maintaining stability are the posture first strategy (prioritization of balance) and posture second strategy (prioritization of concurrent tasks). The existence of these strategies was examined in 13 below-knee prosthesis users and 15 controls during dual-task standing under increasing postural and cognitive challenge by evaluating path length, 95% sway area, and anterior-posterior and medial-lateral amplitudes of the center of pressure. The subjects stood on two force platforms under usual (hard surface/eyes open) and difficult (soft surface/eyes closed) conditions, first alone and while performing a cognitive task without and then with instruction on cognitive prioritization. During standing alone, sway was not significantly different between groups. After adding the cognitive task without prioritization instruction, prosthesis users increased sway more under the dual-task than single-task standing (p ≤ 0.028) during both usual and difficult conditions, favoring the posture second strategy. Controls, however, reduced dual-task sway under a greater postural challenge (p ≤ 0.017), suggesting the posture first strategy. With prioritization of the cognitive task, sway was unchanged or reduced in prosthesis users, suggesting departure from the posture second strategy, whereas controls maintained the posture first strategy. Individual analysis of dual tasking revealed that greater postural demand in controls and greater cognitive challenge in prosthesis users led to both reduced sway and improved cognitive performance, suggesting cognitive-motor facilitation. Thus, activation of additional resources through increased alertness, rather than posture prioritization, may explain dual-task performance in both prosthesis users and controls under increasing postural and cognitive challenge.

Movement Interferes with Visuospatial Working Memory during the Encoding: An ERP Study

PubMed Central

Gunduz Can, Rumeysa; Schack, Thomas; Koester, Dirk

2017-01-01

The present study focuses on the functional interactions of cognition and manual action control. Particularly, we investigated the neurophysiological correlates of the dual-task costs of a manual-motor task (requiring grasping an object, holding it, and subsequently placing it on a target) for working memory (WM) domains (verbal and visuospatial) and processes (encoding and retrieval). Thirty participants were tested in a cognitive-motor dual-task paradigm, in which a single block (a verbal or visuospatial WM task) was compared with a dual block (concurrent performance of a WM task and a motor task). Event-related potentials (ERPs) were analyzed separately for the encoding and retrieval processes of verbal and visuospatial WM domains both in single and dual blocks. The behavioral analyses show that the motor task interfered with WM and decreased the memory performance. The performance decrease was larger for the visuospatial task compared with the verbal task, i.e., domain-specific memory costs were obtained. The ERP analyses show the domain-specific interference also at the neurophysiological level, which is further process-specific to encoding. That is, comparing the patterns of WM-related ERPs in the single block and dual block, we showed that visuospatial ERPs changed only for the encoding process when a motor task was performed at the same time. Generally, the present study provides evidence for domain- and process-specific interactions of a prepared manual-motor movement with WM (visuospatial domain during the encoding process). This study, therefore, provides an initial neurophysiological characterization of functional interactions of WM and manual actions in a cognitive-motor dual-task setting, and contributes to a better understanding of the neuro-cognitive mechanisms of motor action control. PMID:28611714

Effects of working memory load on visual selective attention: behavioral and electrophysiological evidence.

PubMed

Pratt, Nikki; Willoughby, Adrian; Swick, Diane

2011-01-01

Working memory and attention interact in a way that enables us to focus on relevant items and maintain current goals. The influence of working memory on attention has been noted in several studies using dual task designs. Multitasking increases the demands on working memory and reduces the amount of resources available for cognitive control functions such as resolving stimulus conflict. However, few studies have investigated the temporal activation of the cortex while multitasking. The present study addresses the extent to which working memory load influences early (P1) and late (P300) attention-sensitive event-related potential components using a dual task paradigm. Participants performed an arrow flanker task alone (single task condition) or concurrently with a Sternberg memory task (dual task condition). In the flanker task, participants responded to the direction of a central arrow surrounded by congruent or incongruent arrows. In the dual task condition, participants were presented with a Sternberg task that consisted of either four or seven consonants to remember prior to a short block of flanker trials. Participants were slower and less accurate on incongruent versus congruent trials. Furthermore, accuracy on incongruent trials was reduced in both dual task conditions. Likewise, P300 amplitude to incongruent flanker stimuli decreased when working memory load increased. These findings suggest that interference from incongruent flankers was more difficult to suppress when working memory was taxed. In addition, P1 amplitude was diminished on all flanker trials in the dual task condition. This result indicates that top-down attentional control over early visual processing is diminished by increasing demands on working memory. Both the behavioral and electrophysiological results suggest that working memory is critical in maintaining attentional focus and resolving conflict.

Effects of Working Memory Load on Visual Selective Attention: Behavioral and Electrophysiological Evidence

PubMed Central

Pratt, Nikki; Willoughby, Adrian; Swick, Diane

2011-01-01

Working memory and attention interact in a way that enables us to focus on relevant items and maintain current goals. The influence of working memory on attention has been noted in several studies using dual task designs. Multitasking increases the demands on working memory and reduces the amount of resources available for cognitive control functions such as resolving stimulus conflict. However, few studies have investigated the temporal activation of the cortex while multitasking. The present study addresses the extent to which working memory load influences early (P1) and late (P300) attention-sensitive event-related potential components using a dual task paradigm. Participants performed an arrow flanker task alone (single task condition) or concurrently with a Sternberg memory task (dual task condition). In the flanker task, participants responded to the direction of a central arrow surrounded by congruent or incongruent arrows. In the dual task condition, participants were presented with a Sternberg task that consisted of either four or seven consonants to remember prior to a short block of flanker trials. Participants were slower and less accurate on incongruent versus congruent trials. Furthermore, accuracy on incongruent trials was reduced in both dual task conditions. Likewise, P300 amplitude to incongruent flanker stimuli decreased when working memory load increased. These findings suggest that interference from incongruent flankers was more difficult to suppress when working memory was taxed. In addition, P1 amplitude was diminished on all flanker trials in the dual task condition. This result indicates that top-down attentional control over early visual processing is diminished by increasing demands on working memory. Both the behavioral and electrophysiological results suggest that working memory is critical in maintaining attentional focus and resolving conflict. PMID:21716633

Noninvasive imaging of prefrontal activation during attention-demanding tasks performed while walking using a wearable optical topography system

NASA Astrophysics Data System (ADS)

Atsumori, Hirokazu; Kiguchi, Masashi; Katura, Takusige; Funane, Tsukasa; Obata, Akiko; Sato, Hiroki; Manaka, Takaaki; Iwamoto, Mitsumasa; Maki, Atsushi; Koizumi, Hideaki; Kubota, Kisou

2010-07-01

Optical topography (OT) based on near-infrared spectroscopy is a noninvasive technique for mapping the relative concentration changes in oxygenated and deoxygenated hemoglobin (oxy- and deoxy-Hb, respectively) in the human cerebral cortex. In our previous study, we developed a small and light wearable optical topography (WOT) system that covers the entire forehead for monitoring prefrontal activation. In the present study, we examine whether the WOT system is applicable to OT measurement while walking, which has been difficult with conventional OT systems. We conduct OT measurements while subjects perform an attention-demanding (AD) task of balancing a ping-pong ball on a small card while walking. The measured time course and power spectra of the relative concentration changes in oxy- and deoxy-Hb show that the step-related changes in the oxy- and deoxy-Hb signals are negligible compared to the task-related changes. Statistical assessment of the task-related changes in the oxy-Hb signals show that the dorsolateral prefrontal cortex and rostral prefrontal area are significantly activated during the AD task. These results suggest that our functional imaging technique with the WOT system is applicable to OT measurement while walking, and will be a powerful tool for evaluating brain activation in a natural environment.

Quantitative assessment of gait and neurochemical correlation in a classical murine model of Parkinson's disease.

PubMed

Wang, Xiao Hong; Lu, Gang; Hu, Xiang; Tsang, Kam Sze; Kwong, Wing Hang; Wu, Feng Xia; Meng, Hai Wei; Jiang, Shu; Liu, Shu Wei; Ng, Ho Keung; Poon, Wai Sang

2012-11-14

Gait deficits are important clinical symptoms of Parkinson's disease (PD). However, existing behavioral tests for the detection of motor impairments in rodents with systemic dopamine depletion only measure akinesia and dyskinesia, and data focusing on gait are scarce. We evaluated gait changes in the methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced C57BL/6 murine model of PD by using a computer-assisted CatWalk system. Correlations of gait parameters with tyrosine hydroxylase (TH) protein levels in the substantia nigra (SN) were also investigated. The gait readouts, including the walking duration, variation of walking speed, step cycle, duty cycle, stance, initial dual stance, terminal dual stance, three- and four-point supports, and the base of support between hind limbs was noted to increase significantly one week after MPTP injection. In contrast, values of the stride length, cadence, swing speed, and diagonal dual support decreased substantially following MPTP treatment (p < 0.05). All of these changes lasted for three weeks after the last MPTP administration. Except for the stance in the fore limbs and the swing speed in the hind limbs, the gait variability in the PD mice showed a closer correlation with the protein levels of TH in the SN than the walking distances in the conventional open field test. Coordination parameters of the regularity index and step pattern were not affected in mice treated with MPTP. Data of the study suggest that the computer-assisted CatWalk system can provide reliable and objective criteria to stratify gait changes arising from MPTP-induced bilateral lesions in C57/BL6 mice. The extent of gait changes was noted to correlate with the expression of the biomarker for dopaminergic neurons. This novel analytical method may hold promise in the study of disease progression and new drug screening in a murine PD model.

Quantitative assessment of gait and neurochemical correlation in a classical murine model of Parkinson’s disease

PubMed Central

2012-01-01

Background Gait deficits are important clinical symptoms of Parkinson’s disease (PD). However, existing behavioral tests for the detection of motor impairments in rodents with systemic dopamine depletion only measure akinesia and dyskinesia, and data focusing on gait are scarce. We evaluated gait changes in the methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced C57BL/6 murine model of PD by using a computer-assisted CatWalk system. Correlations of gait parameters with tyrosine hydroxylase (TH) protein levels in the substantia nigra (SN) were also investigated. Results The gait readouts, including the walking duration, variation of walking speed, step cycle, duty cycle, stance, initial dual stance, terminal dual stance, three- and four-point supports, and the base of support between hind limbs was noted to increase significantly one week after MPTP injection. In contrast, values of the stride length, cadence, swing speed, and diagonal dual support decreased substantially following MPTP treatment (p < 0.05). All of these changes lasted for three weeks after the last MPTP administration. Except for the stance in the fore limbs and the swing speed in the hind limbs, the gait variability in the PD mice showed a closer correlation with the protein levels of TH in the SN than the walking distances in the conventional open field test. Coordination parameters of the regularity index and step pattern were not affected in mice treated with MPTP. Conclusion Data of the study suggest that the computer-assisted CatWalk system can provide reliable and objective criteria to stratify gait changes arising from MPTP-induced bilateral lesions in C57/BL6 mice. The extent of gait changes was noted to correlate with the expression of the biomarker for dopaminergic neurons. This novel analytical method may hold promise in the study of disease progression and new drug screening in a murine PD model. PMID:23151254

Psychometric Functions of Dual-Task Paradigms for Measuring Listening Effort.

PubMed

Wu, Yu-Hsiang; Stangl, Elizabeth; Zhang, Xuyang; Perkins, Joanna; Eilers, Emily

The purpose of the study was to characterize the psychometric functions that describe task performance in dual-task listening effort measures as a function of signal to noise ratio (SNR). Younger adults with normal hearing (YNH, n = 24; experiment 1) and older adults with hearing impairment (n = 24; experiment 2) were recruited. Dual-task paradigms wherein the participants performed a primary speech recognition task simultaneously with a secondary task were conducted at a wide range of SNRs. Two different secondary tasks were used: an easy task (i.e., a simple visual reaction-time task) and a hard task (i.e., the incongruent Stroop test). The reaction time (RT) quantified the performance of the secondary task. For both participant groups and for both easy and hard secondary tasks, the curves that described the RT as a function of SNR were peak shaped. The RT increased as SNR changed from favorable to intermediate SNRs, and then decreased as SNRs moved from intermediate to unfavorable SNRs. The RT reached its peak (longest time) at the SNRs at which the participants could understand 30 to 50% of the speech. In experiments 1 and 2, the dual-task trials that had the same SNR were conducted in one block. To determine if the peak shape of the RT curves was specific to the blocked SNR presentation order used in these experiments, YNH participants were recruited (n = 25; experiment 3) and dual-task measures, wherein the SNR was varied from trial to trial (i.e., nonblocked), were conducted. The results indicated that, similar to the first two experiments, the RT curves had a peak shape. Secondary task performance was poorer at the intermediate SNRs than at the favorable and unfavorable SNRs. This pattern was observed for both YNH and older adults with hearing impairment participants and was not affected by either task type (easy or hard secondary task) or SNR presentation order (blocked or nonblocked). The shorter RT at the unfavorable SNRs (speech intelligibility < 30%) possibly reflects that the participants experienced cognitive overload and/or disengaged themselves from the listening task. The implication of using the dual-task paradigm as a listening effort measure is discussed.

Orienting attention in visual working memory requires central capacity: decreased retro-cue effects under dual-task conditions.

PubMed

Janczyk, Markus; Berryhill, Marian E

2014-04-01

The retro-cue effect (RCE) describes superior working memory performance for validly cued stimulus locations long after encoding has ended. Importantly, this happens with delays beyond the range of iconic memory. In general, the RCE is a stable phenomenon that emerges under varied stimulus configurations and timing parameters. We investigated its susceptibility to dual-task interference to determine the attentional requirements at the time point of cue onset and encoding. In Experiment 1, we compared single- with dual-task conditions. In Experiment 2, we borrowed from the psychological refractory period paradigm and compared conditions with high and low (dual-) task overlap. The secondary task was always binary tone discrimination requiring a manual response. Across both experiments, an RCE was found, but it was diminished in magnitude in the critical dual-task conditions. A previous study did not find evidence that sustained attention is required in the interval between cue offset and test. Our results apparently contradict these findings and point to a critical time period around cue onset and briefly thereafter during which attention is required.

Orienting attention in visual working memory requires central capacity: Decreased retro-cue effects under dual-task conditions

PubMed Central

Berryhill, Marian E.

2014-01-01

The retro-cue effect (RCE) describes superior working memory performance for validly cued stimulus locations long after encoding has ended. Importantly, this happens with delays beyond the range of iconic memory. In general, the RCE is a stable phenomenon that emerges under varied stimulus configurations and timing parameters. We investigated its susceptibility to dual-task interference to determine the attentional requirements at the time point of cue onset and encoding. In Experiment 1, we compared single- with dual-task conditions. In Experiment 2, we borrowed from the psychological refractory period paradigm and compared conditions with high and low (dual-) task overlap. The secondary task was always binary tone discrimination requiring amanual response. Across both experiments, an RCE was found, but it was diminished in magnitude in the critical dual-task conditions. A previous study did not find evidence that sustained attention is required in the interval between cue offset and test. Our results apparently contradict these findings and point to a critical time period around cue onset and briefly thereafter during which attention is required. PMID:24452383

On the costs of parallel processing in dual-task performance: The case of lexical processing in word production.

PubMed

Paucke, Madlen; Oppermann, Frank; Koch, Iring; Jescheniak, Jörg D

2015-12-01

Previous dual-task picture-naming studies suggest that lexical processes require capacity-limited processes and prevent other tasks to be carried out in parallel. However, studies involving the processing of multiple pictures suggest that parallel lexical processing is possible. The present study investigated the specific costs that may arise when such parallel processing occurs. We used a novel dual-task paradigm by presenting 2 visual objects associated with different tasks and manipulating between-task similarity. With high similarity, a picture-naming task (T1) was combined with a phoneme-decision task (T2), so that lexical processes were shared across tasks. With low similarity, picture-naming was combined with a size-decision T2 (nonshared lexical processes). In Experiment 1, we found that a manipulation of lexical processes (lexical frequency of T1 object name) showed an additive propagation with low between-task similarity and an overadditive propagation with high between-task similarity. Experiment 2 replicated this differential forward propagation of the lexical effect and showed that it disappeared with longer stimulus onset asynchronies. Moreover, both experiments showed backward crosstalk, indexed as worse T1 performance with high between-task similarity compared with low similarity. Together, these findings suggest that conditions of high between-task similarity can lead to parallel lexical processing in both tasks, which, however, does not result in benefits but rather in extra performance costs. These costs can be attributed to crosstalk based on the dual-task binding problem arising from parallel processing. Hence, the present study reveals that capacity-limited lexical processing can run in parallel across dual tasks but only at the expense of extraordinary high costs. (c) 2015 APA, all rights reserved).

A Novel Eye-Tracking Method to Assess Attention Allocation in Individuals with and without Aphasia Using a Dual-Task Paradigm

PubMed Central

Heuer, Sabine; Hallowell, Brooke

2015-01-01

Numerous authors report that people with aphasia have greater difficulty allocating attention than people without neurological disorders. Studying how attention deficits contribute to language deficits is important. However, existing methods for indexing attention allocation in people with aphasia pose serious methodological challenges. Eye-tracking methods have great potential to address such challenges. We developed and assessed the validity of a new dual-task method incorporating eye tracking to assess attention allocation. Twenty-six adults with aphasia and 33 control participants completed auditory sentence comprehension and visual search tasks. To test whether the new method validly indexes well-documented patterns in attention allocation, demands were manipulated by varying task complexity in single- and dual-task conditions. Differences in attention allocation were indexed via eye-tracking measures. For all participants significant increases in attention allocation demands were observed from single- to dual-task conditions and from simple to complex stimuli. Individuals with aphasia had greater difficulty allocating attention with greater task demands. Relationships between eye-tracking indices of comprehension during single and dual tasks and standardized testing were examined. Results support the validity of the novel eye-tracking method for assessing attention allocation in people with and without aphasia. Clinical and research implications are discussed. PMID:25913549

The effects of aging on postural control and selective attention when stepping down while performing a concurrent auditory response task.

PubMed

Tsang, William W N; Lam, Nazca K Y; Lau, Kit N L; Leung, Harry C H; Tsang, Crystal M S; Lu, Xi

2013-12-01

To investigate the effects of aging on postural control and cognitive performance in single- and dual-tasking. A cross-sectional comparative design was conducted in a university motion analysis laboratory. Young adults (n = 30; age 21.9 ± 2.4 years) and older adults (n = 30; age 71.9 ± 6.4 years) were recruited. Postural control after stepping down was measured with and without performing a concurrent auditory response task. Measurement included: (1) reaction time and (2) error rate in performing the cognitive task; (3) total sway path and (4) total sway area after stepping down. Our findings showed that the older adults had significantly longer reaction times and higher error rates than the younger subjects in both the single-tasking and dual-tasking conditions. The older adults had significantly longer reaction times and higher error rates when dual-tasking compared with single-tasking, but the younger adults did not. The older adults demonstrated significantly less total sway path, but larger total sway area in single-leg stance after stepping down than the young adults. The older adults showed no significant change in total sway path and area between the dual-tasking and when compared with single-tasking conditions, while the younger adults showed significant decreases in sway. Older adults prioritize postural control by sacrificing cognitive performance when faced with dual-tasking.

On the importance of Task 1 and error performance measures in PRP dual-task studies.

PubMed

Strobach, Tilo; Schütz, Anja; Schubert, Torsten

2015-01-01

The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects.

On the importance of Task 1 and error performance measures in PRP dual-task studies

PubMed Central

Strobach, Tilo; Schütz, Anja; Schubert, Torsten

2015-01-01

The psychological refractory period (PRP) paradigm is a dominant research tool in the literature on dual-task performance. In this paradigm a first and second component task (i.e., Task 1 and Task 2) are presented with variable stimulus onset asynchronies (SOAs) and priority to perform Task 1. The main indicator of dual-task impairment in PRP situations is an increasing Task 2-RT with decreasing SOAs. This impairment is typically explained with some task components being processed strictly sequentially in the context of the prominent central bottleneck theory. This assumption could implicitly suggest that processes of Task 1 are unaffected by Task 2 and bottleneck processing, i.e., decreasing SOAs do not increase reaction times (RTs) and error rates of the first task. The aim of the present review is to assess whether PRP dual-task studies included both RT and error data presentations and statistical analyses and whether studies including both data types (i.e., RTs and error rates) show data consistent with this assumption (i.e., decreasing SOAs and unaffected RTs and/or error rates in Task 1). This review demonstrates that, in contrast to RT presentations and analyses, error data is underrepresented in a substantial number of studies. Furthermore, a substantial number of studies with RT and error data showed a statistically significant impairment of Task 1 performance with decreasing SOA. Thus, these studies produced data that is not primarily consistent with the strong assumption that processes of Task 1 are unaffected by Task 2 and bottleneck processing in the context of PRP dual-task situations; this calls for a more careful report and analysis of Task 1 performance in PRP studies and for a more careful consideration of theories proposing additions to the bottleneck assumption, which are sufficiently general to explain Task 1 and Task 2 effects. PMID:25904890

A new semantic vigilance task: vigilance decrement, workload, and sensitivity to dual-task costs.

PubMed

Epling, Samantha L; Russell, Paul N; Helton, William S

2016-01-01

Cognitive resource theory is a common explanation for both the performance decline in vigilance tasks, known as the vigilance decrement, and the limited ability to perform multiple tasks simultaneously. The limited supply of cognitive resources may be utilized faster than they are replenished resulting in a performance decrement, or may need to be allocated among multiple tasks with some performance cost. Researchers have proposed both domain-specific, for example spatial versus verbal processing resources, and domain general cognitive resources. One challenge in testing the domain specificity of cognitive resources in vigilance is the current lack of difficult semantic vigilance tasks which reliably produce a decrement. In the present research, we investigated whether the vigilance decrement was found in a new abbreviated semantic discrimination vigilance task, and whether there was a performance decrement in said vigilance task when paired with a word recall task, as opposed to performed individually. As hypothesized, a vigilance decrement in the semantic vigilance task was found in both the single-task and dual-task conditions, along with reduced vigilance performance in the dual-task condition and reduced word recall in the dual-task condition. This is consistent with cognitive resource theory. The abbreviated semantic vigilance task will be a useful tool for researchers interested in determining the specificity of cognitive resources utilized in vigilance tasks.

Altered steering strategies for goal-directed locomotion in stroke

PubMed Central

2013-01-01

Background Individuals who have sustained a stroke can manifest altered locomotor steering behaviors when exposed to optic flows expanding from different locations. Whether these alterations persist in the presence of a visible goal and whether they can be explained by the presence of a perceptuo-motor disorder remain unknown. The purpose of this study was to compare stroke participants and healthy participants on their ability to control heading while exposed to changing optic flows and target locations. Methods Ten participants with stroke (55.6 ± 9.3 yrs) and ten healthy controls (57.0 ± 11.5 yrs) participated in a mouse-driven steering task (perceptuo-motor task) while seated and in a walking steering task. In the seated steering task, participants were instructed to head or ‘walk’ toward a target in the virtual environment by using a mouse while wearing a helmet-mounted display (HMD). In the walking task, participants performed a similar steering task in the same virtual environment while walking overground at their comfortable speed. For both experiments, the target and/or the focus of expansion (FOE) of the optic flow shifted to the side (±20°) or remained centered. The main outcome measure was net heading errors (NHE). Secondary outcomes included mediolateral displacement, horizontal head orientation, and onsets of heading and head reorientation. Results In the walking steering task, the presence of FOE shifts modulated the extent and timing of mediolateral displacement and head rotation changes, as well as NHE magnitudes. Participants overshot and undershot their net heading, respectively, in response to ipsilateral and contralateral FOE and target shifts. Stroke participants made larger NHEs, especially when the FOE was shifted towards the non-paretic side. In the seated steering task, similar NHEs were observed between stroke and healthy participants. Conclusions The findings highlight the fine coordination between rotational and translational steering mechanisms in presence of targets and FOE shifts. The altered performance of stroke participants in walking but not in the seated steering task suggests that an altered perceptuo-motor processing of optic flow is not a main contributing factor and that other stroke-related sensorimotor deficits are involved. PMID:23875969

Dual-task and anticipation impact lower limb biomechanics during a single-leg cut with body borne load.

PubMed

Seymore, Kayla D; Cameron, Sarah E; Kaplan, Jonathan T; Ramsay, John W; Brown, Tyler N

2017-12-08

This study quantified how a dual cognitive task impacts lower limb biomechanics during anticipated and unanticipated single-leg cuts with body borne load. Twenty-four males performed anticipated and unanticipated cuts with and without a dual cognitive task with three load conditions: no load (∼6 kg), medium load (15% of BW), and heavy load (30% of BW). Lower limb biomechanics were submitted to a repeated measures linear mixed model to test the main and interaction effects of load, anticipation, and dual task. With body borne load, participants increased peak stance (PS) hip flexion (p = .004) and hip internal rotation (p = .001) angle, and PS hip flexion (p = .001) and internal rotation (p = .018), and knee flexion (p = .016) and abduction (p = .001) moments. With the dual task, participants decreased PS knee flexion angle (p < .001) and hip flexion moment (p = .027), and increased PS knee external rotation angle (p = .034). During the unanticipated cut, participants increased PS hip (p = .040) and knee flexion angle (p < .001), and decreased PS hip adduction (p = .001), and knee abduction (p = .005) and external rotation (p = .026) moments. Adding body borne load produces lower limb biomechanical adaptations thought to increase risk of musculoskeletal injury, but neither anticipation nor dual task exaggerated those biomechanical adaptations. With a dual task, participants adopted biomechanics known to increase injury risk; whereas, participants used lower limb biomechanics thought to decrease injury risk during unanticipated cuts. Copyright © 2017 Elsevier Ltd. All rights reserved.

Age-Related Differences in Listening Effort During Degraded Speech Recognition.

PubMed

Ward, Kristina M; Shen, Jing; Souza, Pamela E; Grieco-Calub, Tina M

The purpose of the present study was to quantify age-related differences in executive control as it relates to dual-task performance, which is thought to represent listening effort, during degraded speech recognition. Twenty-five younger adults (YA; 18-24 years) and 21 older adults (OA; 56-82 years) completed a dual-task paradigm that consisted of a primary speech recognition task and a secondary visual monitoring task. Sentence material in the primary task was either unprocessed or spectrally degraded into 8, 6, or 4 spectral channels using noise-band vocoding. Performance on the visual monitoring task was assessed by the accuracy and reaction time of participants' responses. Performance on the primary and secondary task was quantified in isolation (i.e., single task) and during the dual-task paradigm. Participants also completed a standardized psychometric measure of executive control, including attention and inhibition. Statistical analyses were implemented to evaluate changes in listeners' performance on the primary and secondary tasks (1) per condition (unprocessed vs. vocoded conditions); (2) per task (single task vs. dual task); and (3) per group (YA vs. OA). Speech recognition declined with increasing spectral degradation for both YA and OA when they performed the task in isolation or concurrently with the visual monitoring task. OA were slower and less accurate than YA on the visual monitoring task when performed in isolation, which paralleled age-related differences in standardized scores of executive control. When compared with single-task performance, OA experienced greater declines in secondary-task accuracy, but not reaction time, than YA. Furthermore, results revealed that age-related differences in executive control significantly contributed to age-related differences on the visual monitoring task during the dual-task paradigm. OA experienced significantly greater declines in secondary-task accuracy during degraded speech recognition than YA. These findings are interpreted as suggesting that OA expended greater listening effort than YA, which may be partially attributed to age-related differences in executive control.

Age-Related Changes in Brain Activation Underlying Single- and Dual-Task Performance: Visuomanual Drawing and Mental Arithmetic

ERIC Educational Resources Information Center

Van Impe, A.; Coxon, J. P.; Goble, D. J.; Wenderoth, N.; Swinnen, S. P.

2011-01-01

Depending on task combination, dual-tasking can either be performed successfully or can lead to performance decrements in one or both tasks. Interference is believed to be caused by limitations in central processing, i.e. structural interference between the neural activation patterns associated with each task. In the present study, single- and…

Selective impairment of masked priming in dual-task performance.

PubMed

Fischer, Rico; Kiesel, Andrea; Kunde, Wilfried; Schubert, Torsten

2011-03-01

This study investigated the impact of divided attention on masked priming. In a dual-task setting, two tasks had to be carried out in close temporal succession: a tone discrimination task and a masked priming task. The order of the tasks was varied between experiments, and attention was always allocated to the first task-that is, the first task was prioritized. The priming task was the second (nonprioritized) task in Experiment 1 and the first (prioritized) task in Experiment 2. In both experiments, "novel" prime stimuli associated with semantic processing were essentially ineffective. However, there was intact priming by another type of prime stimuli associated with response priming. Experiment 3 showed that all these prime stimuli can reveal significant priming effects during a task-switching paradigm in which both tasks were performed consecutively. We conclude that dual-task specific interference processes (e.g., the simultaneous coordination of multiple stimulus-response rules) selectively impair priming that is assumed to rely on semantic processing.

Measuring listening effort: driving simulator vs. simple dual-task paradigm

PubMed Central

Wu, Yu-Hsiang; Aksan, Nazan; Rizzo, Matthew; Stangl, Elizabeth; Zhang, Xuyang; Bentler, Ruth

2014-01-01

Objectives The dual-task paradigm has been widely used to measure listening effort. The primary objectives of the study were to (1) investigate the effect of hearing aid amplification and a hearing aid directional technology on listening effort measured by a complicated, more real world dual-task paradigm, and (2) compare the results obtained with this paradigm to a simpler laboratory-style dual-task paradigm. Design The listening effort of adults with hearing impairment was measured using two dual-task paradigms, wherein participants performed a speech recognition task simultaneously with either a driving task in a simulator or a visual reaction-time task in a sound-treated booth. The speech materials and road noises for the speech recognition task were recorded in a van traveling on the highway in three hearing aid conditions: unaided, aided with omni directional processing (OMNI), and aided with directional processing (DIR). The change in the driving task or the visual reaction-time task performance across the conditions quantified the change in listening effort. Results Compared to the driving-only condition, driving performance declined significantly with the addition of the speech recognition task. Although the speech recognition score was higher in the OMNI and DIR conditions than in the unaided condition, driving performance was similar across these three conditions, suggesting that listening effort was not affected by amplification and directional processing. Results from the simple dual-task paradigm showed a similar trend: hearing aid technologies improved speech recognition performance, but did not affect performance in the visual reaction-time task (i.e., reduce listening effort). The correlation between listening effort measured using the driving paradigm and the visual reaction-time task paradigm was significant. The finding showing that our older (56 to 85 years old) participants’ better speech recognition performance did not result in reduced listening effort was not consistent with literature that evaluated younger (approximately 20 years old), normal hearing adults. Because of this, a follow-up study was conducted. In the follow-up study, the visual reaction-time dual-task experiment using the same speech materials and road noises was repeated on younger adults with normal hearing. Contrary to findings with older participants, the results indicated that the directional technology significantly improved performance in both speech recognition and visual reaction-time tasks. Conclusions Adding a speech listening task to driving undermined driving performance. Hearing aid technologies significantly improved speech recognition while driving, but did not significantly reduce listening effort. Listening effort measured by dual-task experiments using a simulated real-world driving task and a conventional laboratory-style task was generally consistent. For a given listening environment, the benefit of hearing aid technologies on listening effort measured from younger adults with normal hearing may not be fully translated to older listeners with hearing impairment. PMID:25083599

Dual-Arm Generalized Compliant Motion With Shared Control

NASA Technical Reports Server (NTRS)

Backes, Paul G.

1994-01-01

Dual-Arm Generalized Compliant Motion (DAGCM) primitive computer program implementing improved unified control scheme for two manipulator arms cooperating in task in which both grasp same object. Provides capabilities for autonomous, teleoperation, and shared control of two robot arms. Unifies cooperative dual-arm control with multi-sensor-based task control and makes complete task-control capability available to higher-level task-planning computer system via large set of input parameters used to describe desired force and position trajectories followed by manipulator arms. Some concepts discussed in "A Generalized-Compliant-Motion Primitive" (NPO-18134).

Dual-Task Processing in Younger and Older Adults: Similarities and Differences Revealed by fMRI

ERIC Educational Resources Information Center

Hartley, Alan A.; Jonides, John; Sylvester, Ching-Yune C.

2011-01-01

fMRI was used to explore age differences in the neural substrate of dual-task processing. Brain activations when there was a 100 ms SOA between tasks, and task overlap was high, were contrasted with activations when there was a 1000 ms SOA, and first task processing was largely complete before the second task began. Younger adults (M = 21 yrs)…

Selecting Tasks for Evaluating Human Performance as a Function of Gravity

NASA Technical Reports Server (NTRS)

Norcross, J. R.; Gernhardt, M. L.

2010-01-01

A challenge in understanding human performance as a function of gravity is determining which tasks to research. Initial studies began with treadmill walking, which was easy to quantify and control. However, with the development of pressurized rovers, it is less important to optimize human performance for ambulation as rovers will likely perform gross translation for them. Future crews are likely to spend much of their extravehicular activity (EVA) performing geology, construction and maintenance type tasks, for which it is difficult to measure steady-state-workloads. To evaluate human performance in reduced gravity, we have collected metabolic, biomechanical and subjective data for different tasks at varied gravity levels. Methods: Ten subjects completed 5 different tasks including weight transfer, shoveling, treadmill walking, treadmill running and treadmill incline walking. All tasks were performed shirt-sleeved at 1-g, 3/8-g and 1/6-g. Off-loaded conditions were achieved via the Active Response Gravity Offload System. Treadmill tasks were performed for 3 minutes with reported oxygen consumption (VO2) averaged over the last 2 minutes. Shoveling was performed for 3 minutes with metabolic cost reported as ml O2 consumed per kg material shoveled. Weight transfer reports metabolic cost as liters O2 consumed to complete the task. Statistical analysis was performed via repeated measures ANOVA. Results: Statistically significant metabolic differences were noted between all 3 gravity levels for treadmill running and incline walking. For the other 3 tasks, there were significant differences between 1-g and each reduced gravity, but not between 1/6-g and 3/8-g. For weight transfer, significant differences were seen between gravities in both trial-average VO2 and time-to-completion with noted differences in strategy for task completion. Conclusion: To determine if gravity has a metabolic effect on human performance, this research may indicate that tasks should be selected that require the subject to work vertically against the force of gravity.

Relative association of processing speed, short-term memory and sustained attention with task on gait speed: a study of community-dwelling people 50 years and older.

PubMed

Killane, Isabelle; Donoghue, Orna A; Savva, George M; Cronin, Hilary; Kenny, Rose Anne; Reilly, Richard B

2014-11-01

For single gait tasks, associations have been reported between gait speed and cognitive domains. However, few studies have evaluated if this association is altered in dual gait tasks given gait speed changes with complexity and nature of task. We evaluated relative contributions of specific elements of cognitive function (including sustained attention and processing speed) to dual task gait speed in a nationally representative population of community-dwelling adults over 50 years. Gait speed was obtained using the GaitRite walkway during three gait tasks: single, cognitive (alternate letters), and motor (carrying a filled glass). Linear regression models, adjusted for covariates, were constructed to predict the relative contributions of seven neuropsychological tests to gait speed differences and to investigate gait task effects. The mean age and gait speed of the population (n = 4,431, 55% women) was 62.4 years (SD = 8.2) and 135.85 cm/s (SD = 20.20, single task), respectively. Poorer processing speed, short-term memory, and sustained attention were major cognitive contributors to slower gait speed for all gait tasks. Both dual gait tasks were robust to covariate adjustment and had a significant additional executive function element not found for the single gait task. For community-dwelling older adults processing speed, short-term memory and sustained attention were independently associated with gait speed for all gait tasks. Dual gait tasks were found to highlight specific executive function elements. This result forms a baseline value for dual task gait speed. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Influence of dual-tasking with different levels of attention diversion on characteristics of the movement-related cortical potential.

PubMed

Aliakbaryhosseinabadi, Susan; Kamavuako, Ernest Nlandu; Jiang, Ning; Farina, Dario; Mrachacz-Kersting, Natalie

2017-11-01

Dual tasking is defined as performing two tasks concurrently and has been shown to have a significant effect on attention directed to the performance of the main task. In this study, an attention diversion task with two different levels was administered while participants had to complete a cue-based motor task consisting of foot dorsiflexion. An auditory oddball task with two levels of complexity was implemented to divert the user's attention. Electroencephalographic (EEG) recordings were made from nine single channels. Event-related potentials (ERPs) confirmed that the oddball task of counting a sequence of two tones decreased the auditory P300 amplitude more than the oddball task of counting one target tone among three different tones. Pre-movement features quantified from the movement-related cortical potential (MRCP) were changed significantly between single and dual-task conditions in motor and fronto-central channels. There was a significant delay in movement detection for the case of single tone counting in two motor channels only (237.1-247.4ms). For the task of sequence counting, motor cortex and frontal channels showed a significant delay in MRCP detection (232.1-250.5ms). This study investigated the effect of attention diversion in dual-task conditions by analysing both ERPs and MRCPs in single channels. The higher attention diversion lead to a significant reduction in specific MRCP features of the motor task. These results suggest that attention division in dual-tasking situations plays an important role in movement execution and detection. This has important implications in designing real-time brain-computer interface systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Heart Rate Response During Mission-Critical Tasks After Space Flight

NASA Technical Reports Server (NTRS)

Arzeno, Natalia M.; Lee, S. M. C.; Stenger, M. B.; Lawrence, E. L.; Platts, S. H.; Bloomberg, J. J.

2010-01-01

Adaptation to microgravity could impair crewmembers? ability to perform required tasks upon entry into a gravity environment, such as return to Earth, or during extraterrestrial exploration. Historically, data have been collected in a controlled testing environment, but it is unclear whether these physiologic measures result in changes in functional performance. NASA?s Functional Task Test (FTT) aims to investigate whether adaptation to microgravity increases physiologic stress and impairs performance during mission-critical tasks. PURPOSE: To determine whether the well-accepted postflight tachycardia observed during standard laboratory tests also would be observed during simulations of mission-critical tasks during and after recovery from short-duration spaceflight. METHODS: Five astronauts participated in the FTT 30 days before launch, on landing day, and 1, 6, and 30 days after landing. Mean heart rate (HR) was measured during 5 simulations of mission-critical tasks: rising from (1) a chair or (2) recumbent seated position followed by walking through an obstacle course (egress from a space vehicle), (3) translating graduated masses from one location to another (geological sample collection), (4) walking on a treadmill at 6.4 km/h (ambulation on planetary surface), and (5) climbing 40 steps on a passive treadmill ladder (ingress to lander). For tasks 1, 2, 3, and 5, astronauts were encouraged to complete the task as quickly as possible. Time to complete tasks and mean HR during each task were analyzed using repeated measures ANOVA and ANCOVA respectively, in which task duration was a covariate. RESULTS: Landing day HR was higher (P < 0.05) than preflight during the upright seat egress (7%+/-3), treadmill walk (13%+/-3) and ladder climb (10%+/-4), and HR remained elevated during the treadmill walk 1 day after landing. During tasks in which HR was not elevated on landing day, task duration was significantly greater on landing day (recumbent seat egress: 25%+/-14 and mass translation: 26%+/-12; P < 0.05). CONCLUSION: Elevated HR and increased task duration during postflight simulations of mission-critical tasks is suggestive of spaceflight-induced deconditioning. Following short-duration microgravity missions (< 16 d), work performance may be transiently impaired, but recovery is rapid.

Interval Timing Deficits Assessed by Time Reproduction Dual Tasks as Cognitive Endophenotypes for Attention-Deficit/Hyperactivity Disorder

PubMed Central

Hwang-Gu, Shoou-Lian; Gau, Susan Shur-Fen

2015-01-01

The literature has suggested timing processing as a potential endophenotype for attention deficit/hyperactivity disorder (ADHD); however, whether the subjective internal clock speed presented by verbal estimation and limited attention capacity presented by time reproduction could be endophenotypes for ADHD is still unknown. We assessed 223 youths with DSM-IV ADHD (age range: 10-17 years), 105 unaffected siblings, and 84 typically developing (TD) youths using psychiatric interviews, intelligence tests, verbal estimation and time reproduction tasks (single task and simple and difficult dual tasks) at 5-second, 12-second, and 17-second intervals. We found that youths with ADHD tended to overestimate time in verbal estimation more than their unaffected siblings and TD youths, implying that fast subjective internal clock speed might be a characteristic of ADHD, rather than an endophenotype for ADHD. Youths with ADHD and their unaffected siblings were less precise in time reproduction dual tasks than TD youths. The magnitude of estimated errors in time reproduction was greater in youths with ADHD and their unaffected siblings than in TD youths, with an increased time interval at the 17-second interval and with increased task demands on both simple and difficult dual tasks versus the single task. Increased impaired time reproduction in dual tasks with increased intervals and task demands were shown in youths with ADHD and their unaffected siblings, suggesting that time reproduction deficits explained by limited attention capacity might be a useful endophenotype of ADHD. PMID:25992899

Gait-Related Brain Activity in People with Parkinson Disease with Freezing of Gait

PubMed Central

Peterson, Daniel S.; Pickett, Kristen A.; Duncan, Ryan; Perlmutter, Joel; Earhart, Gammon M.

2014-01-01

Approximately 50% of people with Parkinson disease experience freezing of gait, described as a transient inability to produce effective stepping. Complex gait tasks such as turning typically elicit freezing more commonly than simple gait tasks, such as forward walking. Despite the frequency of this debilitating and dangerous symptom, the brain mechanisms underlying freezing remain unclear. Gait imagery during functional magnetic resonance imaging permits investigation of brain activity associated with locomotion. We used this approach to better understand neural function during gait-like tasks in people with Parkinson disease who experience freezing- “FoG+” and people who do not experience freezing- ”FoG−“. Nine FoG+ and nine FoG− imagined complex gait tasks (turning, backward walking), simple gait tasks (forward walking), and quiet standing during measurements of blood oxygen level dependent (BOLD) signal. Changes in BOLD signal (i.e. beta weights) during imagined walking and imagined standing were analyzed across FoG+ and FoG− groups in locomotor brain regions including supplementary motor area, globus pallidus, putamen, mesencephalic locomotor region, and cerebellar locomotor region. Beta weights in locomotor regions did not differ for complex tasks compared to simple tasks in either group. Across imagined gait tasks, FoG+ demonstrated significantly lower beta weights in the right globus pallidus with respect to FoG−. FoG+ also showed trends toward lower beta weights in other right-hemisphere locomotor regions (supplementary motor area, mesencephalic locomotor region). Finally, during imagined stand, FoG+ exhibited lower beta weights in the cerebellar locomotor region with respect to FoG−. These data support previous results suggesting FoG+ exhibit dysfunction in a number of cortical and subcortical regions, possibly with asymmetric dysfunction towards the right hemisphere. PMID:24595265

Measures of Time-Sharing Skill and Gender as Predictors of Flight Simulator Performance.

DTIC Science & Technology

1979-01-01

well as overall e- quations including gender as a variable. Besides gender in the overall equations, measures of time-sharing skill were the best ...study indicated the best predictors of dual or whole-task performance were other dual-tasks. Furthermore, the particular components involved in a dual...switching between tasks, or the use of efficient response strategies " (Damos and Wickens, 1977, p.2). Attentional flexibility. According to Keele

Single-task and dual-task tandem gait test performance after concussion.

PubMed

Howell, David R; Osternig, Louis R; Chou, Li-Shan

2017-07-01

To compare single-task and dual-task tandem gait test performance between athletes after concussion with controls on observer-timed, spatio-temporal, and center-of-mass (COM) balance control measurements. Ten participants (19.0±5.5years) were prospectively identified and completed a tandem gait test protocol within 72h of concussion and again 1 week, 2 weeks, 1 month, and 2 months post-injury. Seven uninjured controls (20.0±4.5years) completed the same protocol in similar time increments. Tandem gait test trials were performed with (dual-task) and without (single-task) concurrently performing a cognitive test as whole-body motion analysis was performed. Outcome variables included test completion time, average tandem gait velocity, cadence, and whole-body COM frontal plane displacement. Concussion participants took significantly longer to complete the dual-task tandem gait test than controls throughout the first 2 weeks post-injury (mean time=16.4 [95% CI: 13.4-19.4] vs. 10.1 [95% CI: 6.4-13.7] seconds; p=0.03). Single-task tandem gait times were significantly lower 72h post-injury (p=0.04). Dual-task cadence was significantly lower for concussion participants than controls (89.5 [95% CI: 68.6-110.4] vs. 127.0 [95% CI: 97.4-156.6] steps/minute; p=0.04). Moderately-high to high correlations between tandem gait test time and whole-body COM medial-lateral displacement were detected at each time point during dual-task gait (r s =0.70-0.93; p=0.03-0.001). Adding a cognitive task during the tandem gait test resulted in longer detectable deficits post-concussion compared to the traditional single-task tandem gait test. As a clinical tool to assess dynamic motor function, tandem gait may assist with return to sport decisions after concussion. Copyright © 2017 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Development of VariLeg, an exoskeleton with variable stiffness actuation: first results and user evaluation from the CYBATHLON 2016.

PubMed

Schrade, Stefan O; Dätwyler, Katrin; Stücheli, Marius; Studer, Kathrin; Türk, Daniel-Alexander; Meboldt, Mirko; Gassert, Roger; Lambercy, Olivier

2018-03-13

Powered exoskeletons are a promising approach to restore the ability to walk after spinal cord injury (SCI). However, current exoskeletons remain limited in their walking speed and ability to support tasks of daily living, such as stair climbing or overcoming ramps. Moreover, training progress for such advanced mobility tasks is rarely reported in literature. The work presented here aims to demonstrate the basic functionality of the VariLeg exoskeleton and its ability to enable people with motor complete SCI to perform mobility tasks of daily life. VariLeg is a novel powered lower limb exoskeleton that enables adjustments to the compliance in the leg, with the objective of improving the robustness of walking on uneven terrain. This is achieved by an actuation system with variable mechanical stiffness in the knee joint, which was validated through test bench experiments. The feasibility and usability of the exoskeleton was tested with two paraplegic users with motor complete thoracic lesions at Th4 and Th12. The users trained three times a week, in 60 min sessions over four months with the aim of participating in the CYBATHLON 2016 competition, which served as a field test for the usability of the exoskeleton. The progress on basic walking skills and on advanced mobility tasks such as incline walking and stair climbing is reported. Within this first study, the exoskeleton was used with a constant knee stiffness. Test bench evaluation of the variable stiffness actuation system demonstrate that the stiffness could be rendered with an error lower than 30 Nm/rad. During training with the exoskeleton, both users acquired proficient skills in basic balancing, walking and slalom walking. In advanced mobility tasks, such as climbing ramps and stairs, only basic (needing support) to intermediate (able to perform task independently in 25% of the attempts) skill levels were achieved. After 4 months of training, one user competed at the CYBATHLON 2016 and was able to perform 3 (stand-sit-stand, slalom and tilted path) out of 6 obstacles of the track. No adverse events occurred during the training or the competition. Demonstration of the applicability to restore ambulation for people with motor complete SCI was achieved. The CYBATHLON highlighted the importance of training and gaining experience in piloting an exoskeleton, which were just as important as the technical realization of the robot.

Beam walking can detect differences in walking balance proficiency across a range of sensorimotor abilities.

PubMed

Sawers, Andrew; Ting, Lena H

2015-02-01

The ability to quantify differences in walking balance proficiency is critical to curbing the rising health and financial costs of falls. Current laboratory-based approaches typically focus on successful recovery of balance while clinical instruments often pose little difficulty for all but the most impaired patients. Rarely do they test motor behaviors of sufficient difficulty to evoke failures in balance control limiting their ability to quantify balance proficiency. Our objective was to test whether a simple beam-walking task could quantify differences in walking balance proficiency across a range of sensorimotor abilities. Ten experts, ten novices, and five individuals with transtibial limb loss performed six walking trials across three different width beams. Walking balance proficiency was quantified as the ratio of distance walked to total possible distance. Balance proficiency was not significantly different between cohorts on the wide-beam, but clear differences between cohorts on the mid and narrow-beams were identified. Experts walked a greater distance than novices on the mid-beam (average of 3.63±0.04m verus 2.70±0.21m out of 3.66m; p=0.009), and novices walked further than amputees (1.52±0.20m; p=0.03). Amputees were unable to walk on the narrow-beam, while experts walked further (3.07±0.14m) than novices (1.55±0.26m; p=0.0005). A simple beam-walking task and an easily collected measure of distance traveled detected differences in walking balance proficiency across sensorimotor abilities. This approach provides a means to safely study and evaluate successes and failures in walking balance in the clinic or lab. It may prove useful in identifying mechanisms underlying falls versus fall recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

Lunar Landing Walking Simulator

NASA Image and Video Library

1965-09-03

Lunar Landing Walking Simulator: Researchers at Langley study the ability of astronauts to walk, run and perform other tasks required during lunar exploration. The Reduced Gravity Simulator gave researchers the opportunity to look at the effects of one-sixth normal gravity on self-locomotion. Several Apollo astronauts practiced lunar waling at the facility.

Building the Bridge as You Walk on It: Didactic Behaviors of Elementary Teachers in a Dual Language Program

ERIC Educational Resources Information Center

Ray, Juliet M.

2008-01-01

While there is evidence that the dual language model has the potential to raise the academic achievement of English language learners (ELLs), the policies mandated through the No Child Left Behind Act do not support maintenance of the student's heritage language which is an integral part of the model. Using symbolic interactionism as a framework,…

Parallel processing of cognitive and physical demands in left and right prefrontal cortices during smartphone use while walking.

PubMed

Takeuchi, Naoyuki; Mori, Takayuki; Suzukamo, Yoshimi; Tanaka, Naofumi; Izumi, Shin-Ichi

2016-02-01

Smartphone use while walking is becoming a public concern owing to an increased risk of falling that can result from cognitive-motor interference. We evaluated prefrontal cortex (PFC) activity in participants playing a smartphone game while walking, in order to elucidate the role of the PFC in the allocation of attention between physical and cognitive demands. Sixteen young and 15 older adults participated in this study. Participants were instructed to perform a touch number-selecting game on a smartphone while walking. The numbers of correct and mistake responses were analyzed as a measure of cognitive performance. Linear trunk accelerations were measured by another smartphone and analyzed for step time and acceleration magnitude as an assay of gait performance. PFC activity during the task was measured using a wearable 16-channel near-infrared spectroscopy system. Smartphone game playing while walking decreased the cognitive and gait performances compared with performances of single-task condition in older group more than in young group. There was no difference in PFC activation during smartphone use while walking between young and older groups, but age appeared to mediate correlation magnitude between PFC activation and changes in performance. In young adults, multiple regression analysis revealed an association of the right PFC with a reduction in acceleration magnitude (β = 0.581, p = 0.023), and an association of the left PFC with an increase in game-playing mistakes (β = -0.556, p = 0.032) during smartphone use while walking. In older adults, multiple regression analysis revealed an association of the middle PFC with a prolongation of step time (β = -0.550, p = 0.042) and of the left PFC with a reduction in acceleration magnitude (β = -0.648, p = 0.012). In young adults, the left PFC inhibited inappropriate action and the right PFC stabilized gait performance. In older adults, a less-lateralized PFC activity pattern suppressed the deterioration of gait performance, but this resulted in impairment on a simultaneous cognitive task. These results suggest that lateralization of motor and cognitive tasks aids in efficient task completion during a complex action such as using a smartphone while walking.

Objects and events as determinants of parallel processing in dual tasks: evidence from the backward compatibility effect.

PubMed

Ellenbogen, Ravid; Meiran, Nachshon

2011-02-01

The backward-compatibility effect (BCE) is a major index of parallel processing in dual tasks and is related to the dependency of Task 1 performance on Task 2 response codes (Hommel, 1998). The results of four dual-task experiments showed that a BCE occurs when the stimuli of both tasks are included in the same visual object (Experiments 1 and 2) or belong to the same perceptual event (Experiments 3 and 4). Thus, the BCE may be modulated by factors that influence whether both task stimuli are included in the same perceptual event (objects, as studied in cognitive experiments, being special cases of events). As with objects, drawing attention to a (selected) event results in the processing of its irrelevant features and may interfere with task execution. (c) 2010 APA, all rights reserved.

Reduced dual-task gait speed is associated with visual Go/No-Go brain network activation in children and adolescents with concussion.

PubMed

Howell, David R; Meehan, William P; Barber Foss, Kim D; Reches, Amit; Weiss, Michal; Myer, Gregory D

2018-05-31

To investigate the association between dual-task gait performance and brain network activation (BNA) using an electroencephalography (EEG)-based Go/No-Go paradigm among children and adolescents with concussion. Participants with a concussion completed a visual Go/No-Go task with collection of electroencephalogram brain activity. Data were treated with BNA analysis, which involves an algorithmic approach to EEG-ERP activation quantification. Participants also completed a dual-task gait assessment. The relationship between dual-task gait speed and BNA was assessed using multiple linear regression models. Participants (n = 20, 13.9 ± 2.3 years of age, 50% female) were tested at a mean of 7.0 ± 2.5 days post-concussion and were symptomatic at the time of testing (post-concussion symptom scale = 40.4 ± 21.9). Slower dual-task average gait speed (mean = 82.2 ± 21.0 cm/s) was significantly associated with lower relative time BNA scores (mean = 39.6 ± 25.8) during the No-Go task (β = 0.599, 95% CI = 0.214, 0.985, p = 0.005, R 2  = 0.405), while controlling for the effect of age and gender. Among children and adolescents with a concussion, slower dual-task gait speed was independently associated with lower BNA relative time scores during a visual Go/No-Go task. The relationship between abnormal gait behaviour and brain activation deficits may be reflective of disruption to multiple functional abilities after concussion.

Musical Training, Bilingualism, and Executive Function: A Closer Look at Task Switching and Dual-Task Performance

ERIC Educational Resources Information Center

Moradzadeh, Linda; Blumenthal, Galit; Wiseheart, Melody

2015-01-01

This study investigated whether musical training and bilingualism are associated with enhancements in specific components of executive function, namely, task switching and dual-task performance. Participants (n = 153) belonging to one of four groups (monolingual musician, bilingual musician, bilingual non-musician, or monolingual non-musician)…

Dual-Task Crosstalk between Saccades and Manual Responses

ERIC Educational Resources Information Center

Huestegge, Lynn; Koch, Iring

2009-01-01

Between-task crosstalk has been discussed as an important source for dual-task costs. In this study, the authors examine concurrently performed saccades and manual responses as a means of studying the role of response-code conflict between 2 tasks. In Experiment 1, participants responded to an imperative auditory stimulus with a left or a right…

Simultaneous dual-task performance reveals parallel response selection after practice

NASA Technical Reports Server (NTRS)

Hazeltine, Eliot; Teague, Donald; Ivry, Richard B.

2002-01-01

E. H. Schumacher, T. L. Seymour, J. M. Glass, D. E. Kieras, and D. E. Meyer (2001) reported that dual-task costs are minimal when participants are practiced and give the 2 tasks equal emphasis. The present research examined whether such findings are compatible with the operation of an efficient response selection bottleneck. Participants trained until they were able to perform both tasks simultaneously without interference. Novel stimulus pairs produced no reaction time costs, arguing against the development of compound stimulus-response associations (Experiment 1). Manipulating the relative onsets (Experiments 2 and 4) and durations (Experiments 3 and 4) of response selection processes did not lead to dual-task costs. The results indicate that the 2 tasks did not share a bottleneck after practice.

31P Magnetic Resonance Spectroscopy Assessment of Muscle Bioenergetics as a Predictor of Gait Speed in the Baltimore Longitudinal Study of Aging.

PubMed

Choi, Seongjin; Reiter, David A; Shardell, Michelle; Simonsick, Eleanor M; Studenski, Stephanie; Spencer, Richard G; Fishbein, Kenneth W; Ferrucci, Luigi

2016-12-01

Aerobic fitness and muscle bioenergetic capacity decline with age; whether such declines explain age-related slowing of walking speed is unclear. We hypothesized that muscle energetics and aerobic capacity are independent correlates of walking speed in simple and challenging performance tests and that they account for the observed age-related decline in walking speed in these same tests. Muscle bioenergetics was assessed as postexercise recovery rate of phosphocreatine (PCr), k PCr , using phosphorus magnetic resonance spectroscopy ( 31 P-MRS) in 126 participants (53 men) of the Baltimore Longitudinal Study of Aging aged 26-91 years (mean = 72 years). Four walking tasks were administered-usual pace over 6 m and 150 seconds and fast pace over 6 m and 400 m. Separately, aerobic fitness was assessed as peak oxygen consumption (peak VO 2 ) using a graded treadmill test. All gait speeds, k PCr , and peak VO 2 were lower with older age. Independent of age, sex, height, and weight, both k PCr and peak VO 2 were positively and significantly associated with fast pace and long distance walking but only peak VO 2 and not k PCr was significantly associated with usual gait speed over 6 m. Both k PCr and peak VO 2 substantially attenuated the association between age and gait speed for all but the least stressful walking task of 6 m at usual pace. Muscle bioenergetics assessed using 31 P-MRS is highly correlated with walking speed and partially explains age-related poorer performance in fast and long walking tasks. Published by Oxford University Press on behalf of The Gerontological Society of America 2016. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Analysis of the impact of a cognitive task on the posture of elderly subjects with depression compared with healthy elderly subjects.

PubMed

Casteran, Matthieu; Putot, Alain; Pfitzenmeyer, François; Thomas, Elizabeth; Manckoundia, Patrick

2016-11-01

While previous studies have demonstrated that depressive elderly subjects (DES) experience difficulties in the processing of simultaneous cognitive tasks, few have examined the coupling of cognitive tasks with seemingly 'automatic' tasks, such as standing upright. Current patient management focuses on pharmacological treatments and cognitive-behavioral therapies. Healthy elderly (HES) and non-treated DES were included. Postural sway in DES was compared with that in HES while in single-task and dual-task conditions. The single-task consisted of standing upright. For the dual-task, the subjects recalled various items from memory or counted while standing upright. Postural sway was evaluated by computing the center of pressure (CoP) area and path length. DES showed greater postural sway than HES in all conditions. The HES showed a greater CoP area in the dual-task than in the single-task conditions. In DES, the CoP area in the single-task condition was similar to that in the dual-task condition. The greater postural sway observed in DES may be a cause of a greater risk of falls. We showed that even seemingly automatic tasks, such as maintaining an upright posture, are affected by depression. These results are important for the management of DES. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Age-Related Imbalance Is Associated With Slower Walking Speed: An Analysis From the National Health and Nutrition Examination Survey.

PubMed

Xie, Yanjun J; Liu, Elizabeth Y; Anson, Eric R; Agrawal, Yuri

Walking speed is an important dimension of gait function and is known to decline with age. Gait function is a process of dynamic balance and motor control that relies on multiple sensory inputs (eg, visual, proprioceptive, and vestibular) and motor outputs. These sensory and motor physiologic systems also play a role in static postural control, which has been shown to decline with age. In this study, we evaluated whether imbalance that occurs as part of healthy aging is associated with slower walking speed in a nationally representative sample of older adults. We performed a cross-sectional analysis of the previously collected 1999 to 2002 National Health and Nutrition Examination Survey (NHANES) data to evaluate whether age-related imbalance is associated with slower walking speed in older adults aged 50 to 85 years (n = 2116). Balance was assessed on a pass/fail basis during a challenging postural task-condition 4 of the modified Romberg Test-and walking speed was determined using a 20-ft (6.10 m) timed walk. Multivariable linear regression was used to evaluate the association between imbalance and walking speed, adjusting for demographic and health-related covariates. A structural equation model was developed to estimate the extent to which imbalance mediates the association between age and slower walking speed. In the unadjusted regression model, inability to perform the NHANES balance task was significantly associated with 0.10 m/s slower walking speed (95% confidence interval: -0.13 to -0.07; P < .01). In the multivariable regression analysis, inability to perform the balance task was significantly associated with 0.06 m/s slower walking speed (95% confidence interval: -0.09 to -0.03; P < .01), an effect size equivalent to 12 years of age. The structural equation model estimated that age-related imbalance mediates 12.2% of the association between age and slower walking speed in older adults. In a nationally representative sample, age-related balance limitation was associated with slower walking speed. Balance impairment may lead to walking speed declines. In addition, reduced static postural control and dynamic walking speed that occur with aging may share common etiologic origins, including the decline in visual, proprioceptive, and vestibular sensory and motor functions.

Dual learning processes in interactive skill acquisition.

PubMed

Fu, Wai-Tat; Anderson, John R

2008-06-01

Acquisition of interactive skills involves the use of internal and external cues. Experiment 1 showed that when actions were interdependent, learning was effective with and without external cues in the single-task condition but was effective only with the presence of external cues in the dual-task condition. In the dual-task condition, actions closer to the feedback were learned faster than actions farther away but this difference was reversed in the single-task condition. Experiment 2 tested how knowledge acquired in single and dual-task conditions would transfer to a new reward structure. Results confirmed the two forms of learning mediated by the secondary task: A declarative memory encoding process that simultaneously assigned credits to actions and a reinforcement-learning process that slowly propagated credits backward from the feedback. The results showed that both forms of learning were engaged during training, but only at the response selection stage, one form of knowledge may dominate over the other depending on the availability of attentional resources. (c) 2008 APA, all rights reserved

Intelligent control and adaptive systems; Proceedings of the Meeting, Philadelphia, PA, Nov. 7, 8, 1989

NASA Technical Reports Server (NTRS)

Rodriguez, Guillermo (Editor)

1990-01-01

Various papers on intelligent control and adaptive systems are presented. Individual topics addressed include: control architecture for a Mars walking vehicle, representation for error detection and recovery in robot task plans, real-time operating system for robots, execution monitoring of a mobile robot system, statistical mechanics models for motion and force planning, global kinematics for manipulator planning and control, exploration of unknown mechanical assemblies through manipulation, low-level representations for robot vision, harmonic functions for robot path construction, simulation of dual behavior of an autonomous system. Also discussed are: control framework for hand-arm coordination, neural network approach to multivehicle navigation, electronic neural networks for global optimization, neural network for L1 norm linear regression, planning for assembly with robot hands, neural networks in dynamical systems, control design with iterative learning, improved fuzzy process control of spacecraft autonomous rendezvous using a genetic algorithm.

The effect of aquatic exercise and education on lowering fall risk in older adults with hip osteoarthritis.

PubMed

Arnold, Cathy M; Faulkner, Robert A

2010-07-01

To evaluate the effect of aquatic exercise and education on fall risk factors in older adults with hip osteoarthritis (OA). Seventy-nine adults, 65 years of age or older with hip OA and at least 1 fall risk factor, were randomly assigned to 1 of 3 groups: aquatics and education (AE; aquatic exercise twice a wk with once-a-wk group education), aquatics only (A; 2 wk aquatic exercise) and control (C; usual activity). Balance, falls efficacy, dual-task function, functional performance (chair stands), and walking performance were measured pre- and postintervention or control period. There was a significant improvement in fall risk factors (full-factorial MANCOVA, baseline values as covariates; p = .038); AE improved in falls efficacy compared with C and in functional performance compared with A and C. The combination of aquatic exercise and education was effective in improving fall risk factors in older adults with arthritis.

Longitudinal effects of bilingualism on dual-tasking

PubMed Central

Josefsson, Maria; Marsh, John E.; Hansson, Patrik; Ljungberg, Jessica K.

2017-01-01

An ongoing debate surrounds whether bilinguals outperform monolinguals in tests of executive processing. The aim of this study was to investigate if there are long-term (10 year) bilingual advantages in executive processing, as indexed by dual-task performance, in a sample that were 40–65 years at baseline. The bilingual (n = 24) and monolingual (n = 24) participants were matched on age, sex, education, fluid intelligence, and study sample. Participants performed free-recall for a 12-item list in three dual-task settings wherein they sorted cards either during encoding, retrieval, or during both encoding and retrieval of the word-list. Free recall without card sorting was used as a reference to compute dual-task costs. The results showed that bilinguals significantly outperformed monolinguals when they performed card-sorting during both encoding and retrieval of the word-list, the condition that presumably placed the highest demands on executive functioning. However, dual-task costs increased over time for bilinguals relative to monolinguals, a finding that is possibly influenced by retirement age and limited use of second language in the bilingual group. PMID:29281654

Information access in a dual-task context: testing a model of optimal strategy selection.

PubMed

Wickens, C D; Seidler, K S

1997-09-01

Pilots were required to access information from a hierarchical aviation database by navigating under single-task conditions (Experiment 1) and when this task was time-shared with an altitude-monitoring task of varying bandwidth and priority (Experiment 2). In dual-task conditions, pilots had 2 viewports available, 1 always used for the information task and the other to be allocated to either task. Dual-task strategy, inferred from the decision of which task to allocate to the 2nd viewport, revealed that allocation was generally biased in favor of the monitoring task and was only partly sensitive to the difficulty of the 2 tasks and their relative priorities. Some dominant sources of navigational difficulties failed to adaptively influence selection strategy. The implications of the results are to provide tools for jumping to the top of the database, to provide 2 viewports into the common database, and to provide training as to the optimum viewport management strategy in a multitask environment.

Metacognition of Multi-Tasking: How Well Do We Predict the Costs of Divided Attention?

PubMed Central

Finley, Jason R.; Benjamin, Aaron S.; McCarley, Jason S.

2014-01-01

Risky multi-tasking, such as texting while driving, may occur because people misestimate the costs of divided attention. In two experiments, participants performed a computerized visual-manual tracking task in which they attempted to keep a mouse cursor within a small target that moved erratically around a circular track. They then separately performed an auditory n-back task. After practicing both tasks separately, participants received feedback on their single-task tracking performance and predicted their dual-task tracking performance before finally performing the two tasks simultaneously. Most participants correctly predicted reductions in tracking performance under dual-task conditions, with a majority overestimating the costs of dual-tasking. However, the between-subjects correlation between predicted and actual performance decrements was near zero. This combination of results suggests that people do anticipate costs of multi-tasking, but have little metacognitive insight on the extent to which they are personally vulnerable to the risks of divided attention, relative to other people. PMID:24490818

Task Prioritization in Dual-Tasking: Instructions versus Preferences

PubMed Central

Jansen, Reinier J.; van Egmond, René; de Ridder, Huib

2016-01-01

The role of task prioritization in performance tradeoffs during multi-tasking has received widespread attention. However, little is known on whether people have preferences regarding tasks, and if so, whether these preferences conflict with priority instructions. Three experiments were conducted with a high-speed driving game and an auditory memory task. In Experiment 1, participants did not receive priority instructions. Participants performed different sequences of single-task and dual-task conditions. Task performance was evaluated according to participants’ retrospective accounts on preferences. These preferences were reformulated as priority instructions in Experiments 2 and 3. The results showed that people differ in their preferences regarding task prioritization in an experimental setting, which can be overruled by priority instructions, but only after increased dual-task exposure. Additional measures of mental effort showed that performance tradeoffs had an impact on mental effort. The interpretation of these findings was used to explore an extension of Threaded Cognition Theory with Hockey’s Compensatory Control Model. PMID:27391779

Information access in a dual-task context: testing a model of optimal strategy selection

NASA Technical Reports Server (NTRS)

Wickens, C. D.; Seidler, K. S.

1997-01-01

Pilots were required to access information from a hierarchical aviation database by navigating under single-task conditions (Experiment 1) and when this task was time-shared with an altitude-monitoring task of varying bandwidth and priority (Experiment 2). In dual-task conditions, pilots had 2 viewports available, 1 always used for the information task and the other to be allocated to either task. Dual-task strategy, inferred from the decision of which task to allocate to the 2nd viewport, revealed that allocation was generally biased in favor of the monitoring task and was only partly sensitive to the difficulty of the 2 tasks and their relative priorities. Some dominant sources of navigational difficulties failed to adaptively influence selection strategy. The implications of the results are to provide tools for jumping to the top of the database, to provide 2 viewports into the common database, and to provide training as to the optimum viewport management strategy in a multitask environment.

Non-visual spatial tasks reveal increased interactions with stance postural control.

PubMed

Woollacott, Marjorie; Vander Velde, Timothy

2008-05-07

The current investigation aimed to contrast the level and quality of dual-task interactions resulting from the combined performance of a challenging primary postural task and three specific, yet categorically dissociated, secondary central executive tasks. Experiments determined the extent to which modality (visual vs. auditory) and code (non-spatial vs. spatial) specific cognitive resources contributed to postural interference in young adults (n=9) in a dual-task setting. We hypothesized that the different forms of executive n-back task processing employed (visual-object, auditory-object and auditory-spatial) would display contrasting levels of interactions with tandem Romberg stance postural control, and that interactions within the spatial domain would be revealed as most vulnerable to dual-task interactions. Across all cognitive tasks employed, including auditory-object (aOBJ), auditory-spatial (aSPA), and visual-object (vOBJ) tasks, increasing n-back task complexity produced correlated increases in verbal reaction time measures. Increasing cognitive task complexity also resulted in consistent decreases in judgment accuracy. Postural performance was significantly influenced by the type of cognitive loading delivered. At comparable levels of cognitive task difficulty (n-back demands and accuracy judgments) the performance of challenging auditory-spatial tasks produced significantly greater levels of postural sway than either the auditory-object or visual-object based tasks. These results suggest that it is the employment of limited non-visual spatially based coding resources that may underlie previously observed visual dual-task interference effects with stance postural control in healthy young adults.

Does Working Memory Enhance or Interfere With Speech Fluency in Adults Who Do and Do Not Stutter? Evidence From a Dual-Task Paradigm.

PubMed

Eichorn, Naomi; Marton, Klara; Schwartz, Richard G; Melara, Robert D; Pirutinsky, Steven

2016-06-01

The present study examined whether engaging working memory in a secondary task benefits speech fluency. Effects of dual-task conditions on speech fluency, rate, and errors were examined with respect to predictions derived from three related theoretical accounts of disfluencies. Nineteen adults who stutter and twenty adults who do not stutter participated in the study. All participants completed 2 baseline tasks: a continuous-speaking task and a working-memory (WM) task involving manipulations of domain, load, and interstimulus interval. In the dual-task portion of the experiment, participants simultaneously performed the speaking task with each unique combination of WM conditions. All speakers showed similar fluency benefits and decrements in WM accuracy as a result of dual-task conditions. Fluency effects were specific to atypical forms of disfluency and were comparable across WM-task manipulations. Changes in fluency were accompanied by reductions in speaking rate but not by corresponding changes in overt errors. Findings suggest that WM contributes to disfluencies regardless of stuttering status and that engaging WM resources while speaking enhances fluency. Further research is needed to verify the cognitive mechanism involved in this effect and to determine how these findings can best inform clinical intervention.

The source of dual-task limitations: Serial or parallel processing of multiple response selections?

PubMed Central

Marois, René

2014-01-01

Although it is generally recognized that the concurrent performance of two tasks incurs costs, the sources of these dual-task costs remain controversial. The serial bottleneck model suggests that serial postponement of task performance in dual-task conditions results from a central stage of response selection that can only process one task at a time. Cognitive-control models, by contrast, propose that multiple response selections can proceed in parallel, but that serial processing of task performance is predominantly adopted because its processing efficiency is higher than that of parallel processing. In the present study, we empirically tested this proposition by examining whether parallel processing would occur when it was more efficient and financially rewarded. The results indicated that even when parallel processing was more efficient and was incentivized by financial reward, participants still failed to process tasks in parallel. We conclude that central information processing is limited by a serial bottleneck. PMID:23864266

Dual-task interference with equal task emphasis: graded capacity sharing or central postponement?

NASA Technical Reports Server (NTRS)

Ruthruff, Eric; Pashler, Harold E.; Hazeltine, Eliot

2003-01-01

Most studies using the psychological refractory period (PRP) design suggest that dual-task performance is limited by a central bottleneck. Because subjects are usually told to emphasize Task 1, however, the bottleneck might reflect a strategic choice rather than a structural limitation. To evaluate the possibility that central operations can proceed in parallel, albeit with capacity limitations, we conducted two dual-task experiments with equal task emphasis. In both experiments, subjects tended to either group responses together or respond to one task well before the other. In addition, stimulus-response compatibility effects were roughly constant across stimulus onset asynchronies (SOAs). At the short SOA, compatibility effects also carried over onto response times for the other task. This pattern of results is difficult to reconcile with the possibility that subjects share capacity roughly equally between simultaneous central operations. However, this pattern is consistent with the existence of a structural central bottleneck.

Revisiting the Development of Time Sharing Using a Dual Motor Task Performance

ERIC Educational Resources Information Center

Getchell, Nancy; Pabreja, Priya

2006-01-01

In this article, the authors discuss and examine how to develop time sharing using a dual motor task and its effects. They state that when one is required to perform two tasks at the same time (time sharing), an individual may experience difficulty in expressing one or both of the tasks. This phenomenon, known as interference, has been studied…

Performance on a functional motor task is enhanced by sleep in middle-aged and older adults.

PubMed

Al-Sharman, Alham; Siengsukon, Catherine F

2014-07-01

Although sleep has been shown to enhance motor skill learning, it remains unclear whether sleep enhances learning of a functional motor task in middle-aged and older individuals. The purpose of this study was to examine whether sleep enhances motor learning of a functional motor task in middle-aged and older adults. Twenty middle-aged and 20 older individuals were randomly assigned to either the sleep condition or the no-sleep condition. Participants in the sleep condition practiced a novel walking task in the evening, and returned the following morning for retesting. Participants in the no-sleep condition practiced the walking task in the morning and returned the same day in the evening for a retest. Outcome measures included time around the walking path and spatiotemporal gait parameters. Only the middle-aged and older adults in the sleep condition demonstrated significant off-line improvement in performance, measured as a decline in time to walk around the novel path and improvement in spatiotemporal gait parameters. The middle-aged and older adults in the no-sleep condition failed to demonstrate off-line improvements in performance of this functional task. This is the first study to provide evidence that sleep facilitates learning a clinically relevant functional motor task in middle-aged and older adults. Because many neurologic conditions occur in the middle-aged and older adults and sleep issues are very prevalent in many neurologic conditions, it is imperative that physical therapists consider sleep as a factor that may impact motor learning and recovery in these individuals. (See Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A73) for more insights from the authors.

Task Integration Facilitates Multitasking.

PubMed

de Oliveira, Rita F; Raab, Markus; Hegele, Mathias; Schorer, Jörg

2017-01-01

The aim of this study was to investigate multi-task integration in a continuous tracking task. We were particularly interested in how manipulating task structure in a dual-task situation affects learning of a constant segment embedded in a pursuit-tracking task. Importantly, we examined if dual-task effects could be attributed to task integration by varying the structural similarity and difficulty of the primary and secondary tasks. In Experiment 1 participants performed a pursuit tracking task while counting high-pitched tones and ignoring low-pitched tones. The tones were either presented randomly or structurally 250 ms before each tracking turn. Experiment 2 increased the motor load of the secondary tasks by asking participants to tap their feet to the tones. Experiment 3 further increased motor load of the primary task by increasing its speed and having participants tracking with their non-dominant hand. The results show that dual-task interference can be moderated by secondary task conditions that match the structure of the primary task. Therefore our results support proposals of task integration in continuous tracking paradigms. We conclude that multi-tasking is not always detrimental for motor learning but can be facilitated through task-integration.

Individual Differences in Dual Task Performance. Final Report.

ERIC Educational Resources Information Center

Lansman, Marcy; Hunt, Earl

This report summarizes the research results and provides a reference. The basic question addressed was, "Is performance on multi-component tasks predicted by performance on the individual components performed separately?" In the first series of experiments, a dual task involving memory and verbal processing components to predict a…

Isolating the Neural Mechanisms of Interference During Continuous Multisensory Dual-task Performance

DTIC Science & Technology

2014-01-01

sion accuracy in each task, the signal detection theory sensitivity measure of d0 was used (Macmillan & Creelman , 1991; Green & Swets, 1966). First...J. (1998). Sources of dual-task interference: Evidence from human electrophysiology. Psychological Science, 9, 223–227. Macmillan, N. A., & Creelman

Effects of Speed and Visual-Target Distance on Toe Trajectory During the Swing Phase of Treadmill Walking

NASA Technical Reports Server (NTRS)

Miller, Christopher A.; Feiveson, Al; Bloomberg, Jacob J.

2007-01-01

Toe trajectory during swing phase is a precise motor control task that can provide insights into the sensorimotor control of the legs. The purpose of this study was to determine changes in vertical toe trajectory during treadmill walking due to changes in walking speed and target distance. For each trial, subjects walked on a treadmill at one of five speeds while performing a dynamic visual acuity task at either a far or near target distance (five speeds two targets distances = ten trials). Toe clearance decreased with increasing speed, and the vertical toe peak just before heel strike increased with increasing speed, regardless of target distance. The vertical toe peak just after toe-off was lower during near-target visual acuity tasks than during far-target tasks, but was not affected by speed. The ankle of the swing leg appeared to be the main joint angle that significantly affected all three toe trajectory events. The foot angle of the swing leg significantly affected toe clearance and the toe peak just before heel strike. These results will be used to enhance the analysis of lower limb kinematics during the sensorimotor treadmill testing, where differing speeds and/or visual target distances may be used.

Brain Activations for Vestibular Stimulation and Dual Tasking Change with Spaceflight

NASA Technical Reports Server (NTRS)

Yuan, Peng; Koppelmans, Vincent; Reuter-Lorenz, Patricia; De Dios, Yiri; Gadd, Nichole; Wood, Scott; Riascos, Roy; Kofman, Igor; Bloomberg, Jacob; Mulavara, Ajitkumar;

Coupling motion between rearfoot and hip and knee joints during walking and single-leg landing.

PubMed

Koshino, Yuta; Yamanaka, Masanori; Ezawa, Yuya; Okunuki, Takumi; Ishida, Tomoya; Samukawa, Mina; Tohyama, Harukazu

2017-12-01

The objective of the current study was to investigate the kinematic relationships between the rearfoot and hip/knee joint during walking and single-leg landing. Kinematics of the rearfoot relative to the shank, knee and hip joints during walking and single-leg landing were analyzed in 22 healthy university students. Kinematic relationships between two types of angular data were assessed by zero-lag cross-correlation coefficients and coupling angles, and were compared between joints and between tasks. During walking, rearfoot eversion/inversion and external/internal rotation were strongly correlated with hip adduction/abduction (R=0.69 and R=0.84), whereas correlations with knee kinematics were not strong (R≤0.51) and varied between subjects. The correlations with hip adduction/abduction were stronger than those with knee kinematics (P<0.001). Most coefficients during single-leg landing were strong (R≥0.70), and greater than those during walking (P<0.001). Coupling angles indicated that hip motion relative to rearfoot motion was greater than knee motion relative to rearfoot motion during both tasks (P<0.001). Interventions to control rearfoot kinematics may affect hip kinematics during dynamic tasks. The coupling motion between the rearfoot and hip/knee joints, especially in the knee, should be considered individually. Copyright © 2017 Elsevier Ltd. All rights reserved.

Three legged walking mobile platform: Kinematic and dynamic analysis and simulation

NASA Technical Reports Server (NTRS)

Mcmurray, Gary V.; Maclaren, Brice K.

1988-01-01

The three legged walker is proposed as a mobile work platform for numerous tasks associated with lunar base site preparation and construction. It is seen as one of several forms of surface transportation, each of which will be best suited for its respective tasks. Utilizing the principle of dynamic stability and taking advantage of the Moon's gravity, it appears to be capable of walking in any radial direction and rotating about a point. Typical curved path walking could involve some combination of the radial and rotational movements. Comprised mainly of a body, six actuators, and six moving parts, it is mechanically quite simple. Each leg connects to the body at a hip joint and has a femur, a knee joint, and a tibia that terminates at a foot. Also capable of enabling or enhancing the dexterity of a series of implements, the walker concept provides a mechanically simple and weight efficient means of drilling, digging, mining, and transporting cargo, and performing other like tasks. A proof of principle machine demonstrated the feasibility of the walking concept.

Human H-reflexes are smaller in difficult beam walking than in normal treadmill walking.

PubMed

Llewellyn, M; Yang, J F; Prochazka, A

1990-01-01

Hoffman (H) reflexes were elicited from the soleus (SOL) muscle while subjects walked on a treadmill and on a narrow beam (3.5 cm wide, raised 34 cm from the floor). The speed of walking on the treadmill was selected for each subject to match the background activation level of their SOL muscle during beam walking. The normal reciprocal activation pattern of the tibialis anterior and SOL muscles in treadmill walking was replaced by a pattern dominated by co-contraction on the beam. In addition, the step cycle duration was more variable and the time spent in the swing phase was reduced on the beam. The H-reflexes were highly modulated in both tasks, the amplitude being high in the stance phase and low in the swing phase. The H-reflex amplitude was on average 40% lower during beam walking than treadmill walking. The relationship between the H-reflex amplitude and the SOL EMG level was quantified by a regression line relating the two variables. The slope of this line was on average 41% lower in beam walking than treadmill walking. The lower H-reflex gain observed in this study and the high level of fusimotor drive observed in cats performing similar tasks suggest that the two mechanisms which control the excitability of this reflex pathway (i.e. fusimotor action and control of transmission at the muscle spindle to moto-neuron synapse) may be controlled independently.

N-back versus Complex Span Working Memory Training.

PubMed

Blacker, Kara J; Negoita, Serban; Ewen, Joshua B; Courtney, Susan M

2017-12-01

Working memory (WM) is the ability to maintain and manipulate task-relevant information in the absence of sensory input. While its improvement through training is of great interest, the degree to which WM training transfers to untrained WM tasks (near transfer) and other untrained cognitive skills (far transfer) remains debated and the mechanism(s) underlying transfer are unclear. Here we hypothesized that a critical feature of dual n-back training is its reliance on maintaining relational information in WM. In Experiment 1, using an individual differences approach, we found evidence that performance on an n-back task was predicted by performance on a measure of relational WM (i.e., WM for vertical spatial relationships independent of absolute spatial locations); whereas the same was not true for a complex span WM task. In Experiment 2, we tested the idea that reliance on relational WM is critical to produce transfer from n-back but not complex span task training. Participants completed adaptive training on either a dual n-back task, a symmetry span task, or on a non-WM active control task. We found evidence of near transfer for the dual n-back group; however, far transfer to a measure of fluid intelligence did not emerge. Recording EEG during a separate WM transfer task, we examined group-specific, training-related changes in alpha power, which are proposed to be sensitive to WM demands and top-down modulation of WM. Results indicated that the dual n-back group showed significantly greater frontal alpha power after training compared to before training, more so than both other groups. However, we found no evidence of improvement on measures of relational WM for the dual n-back group, suggesting that near transfer may not be dependent on relational WM. These results suggest that dual n-back and complex span task training may differ in their effectiveness to elicit near transfer as well as in the underlying neural changes they facilitate.

The effect of atrial-based pacing on exercise capacity as measured by the 6-minute walk test: a substudy of the Canadian Trial of Physiological Pacing (CTOPP).

PubMed

Baranchuk, Adrian; Healey, Jeff S; Thorpe, Kevin E; Morillo, Carlos A; Nair, Girish; Crystal, Eugene; Kerr, Charles R; Connolly, Stuart J

2007-08-01

Although several randomized trials have detected no reduction in major cardiovascular events with the routine use of dual-chamber as opposed to ventricular pacemakers, many individuals continue to advocate their use as a means of improving exercise capacity. The Canadian Trial of Physiological Pacing (CTOPP) trial is the largest trial comparing ventricular pacing to atrial-based pacing (atrial or dual-chamber) in patients with bradycardia. All patients in this trial were asked to complete a 6-minute hall walk test (6MWT) at the time of their first study follow-up. The distance walked in 6 minutes and the patient's heart rate before and immediately after the walk were recorded. Of the 2568 patients in the CTOPP, 76% completed the 6MWT. The mean distance walked was 350 +/- 127 m in the ventricular pacing group and 356 +/- 127 m in the atrial-based group (P = NS). Similarly, there was no difference in the change in heart rate between the two groups (17 +/- 13 vs. 18 +/- 12 bpm: P = NS). However, among patients with an unpaced heart rate of

Differential effects of labyrinthine dysfunction on distance and direction during blindfolded walking of a triangular path.

PubMed

Glasauer, S; Amorim, M-A; Viaud-Delmon, I; Berthoz, A

2002-08-01

While we walk through the environment, we constantly receive inputs from different sensory systems. For us to accomplish a given task, for example to reach a target location, the sensory information has to be integrated to update our knowledge of self-position and self-orientation with respect to the target so that we can correctly plan and perform the remaining trajectory. As has been shown previously, vestibular information plays a minor role in the performance of linear goal-directed locomotion when walking blindfolded toward a previously seen target within a few meters. The present study extends the question of whether vestibular information is a requirement for goal-directed locomotion by studying a more complex task that also involves rotation: walking a triangular path. Furthermore, studying this task provides information about how we walk a given trajectory, how we move around corners, and whether we are able to return to the starting point. Seven young male, five labyrinthine-defective (LD) and five age- and gender-matched control subjects were asked to walk a previously seen triangular path, which was marked on the ground, first without vision (EC) and then with vision (EO). Each subject performed three clockwise (CW) and three counterclockwise (CCW) walks under the EC condition and one CW and CCW walk under the EO condition. The movement of the subjects was recorded by means of a 3D motion analysis system. Analysis of the data showed that LD subjects had, in the EC condition, a significantly larger final arrival error, which was due to increased directional errors during the turns. However, there was no difference between the groups as regards the overall path length walked. This shows that LD subjects were able to plan and execute the given trajectory without vision, but failed to turn correctly around the corners. Hence, the results demonstrate that vestibular information enhances the ability to perform a planned trajectory incorporating whole body rotations when no visual feedback is available.

Age-related differences in listening effort during degraded speech recognition

PubMed Central

Ward, Kristina M.; Shen, Jing; Souza, Pamela E.; Grieco-Calub, Tina M.

2016-01-01

Objectives The purpose of the current study was to quantify age-related differences in executive control as it relates to dual-task performance, which is thought to represent listening effort, during degraded speech recognition. Design Twenty-five younger adults (18–24 years) and twenty-one older adults (56–82 years) completed a dual-task paradigm that consisted of a primary speech recognition task and a secondary visual monitoring task. Sentence material in the primary task was either unprocessed or spectrally degraded into 8, 6, or 4 spectral channels using noise-band vocoding. Performance on the visual monitoring task was assessed by the accuracy and reaction time of participants’ responses. Performance on the primary and secondary task was quantified in isolation (i.e., single task) and during the dual-task paradigm. Participants also completed a standardized psychometric measure of executive control, including attention and inhibition. Statistical analyses were implemented to evaluate changes in listeners’ performance on the primary and secondary tasks (1) per condition (unprocessed vs. vocoded conditions); (2) per task (baseline vs. dual task); and (3) per group (younger vs. older adults). Results Speech recognition declined with increasing spectral degradation for both younger and older adults when they performed the task in isolation or concurrently with the visual monitoring task. Older adults were slower and less accurate than younger adults on the visual monitoring task when performed in isolation, which paralleled age-related differences in standardized scores of executive control. When compared to single-task performance, older adults experienced greater declines in secondary-task accuracy, but not reaction time, than younger adults. Furthermore, results revealed that age-related differences in executive control significantly contributed to age-related differences on the visual monitoring task during the dual-task paradigm. Conclusions Older adults experienced significantly greater declines in secondary-task accuracy during degraded speech recognition than younger adults. These findings are interpreted as suggesting that older listeners expended greater listening effort than younger listeners, and may be partially attributed to age-related differences in executive control. PMID:27556526

Short-term retention of pictures and words as a function of type of distraction and length of delay interval.

PubMed

Pellegrino, J W; Siegel, A W; Dhawan, M

1976-01-01

Picture and word triads were tested in a Brown-Peterson short-term retention task at varying delay intervals (3, 10, or 30 sec) and under acoustic and simultaneous acoustic and visual distraction. Pictures were superior to words at all delay intervals under single acoustic distraction. Dual distraction consistently reduced picture retention while simultaneously facilitating word retention. The results were interpreted in terms of the dual coding hypothesis with modality-specific interference effects in the visual and acoustic processing systems. The differential effects of dual distraction were related to the introduction of visual interference and differential levels of functional acoustic interference across dual and single distraction tasks. The latter was supported by a constant 2/1 ratio in the backward counting rates of the acoustic vs. dual distraction tasks. The results further suggest that retention may not depend on total processing load of the distraction task, per se, but rather that processing load operates within modalities.

Effects of alcohol on attention orienting and dual-task performance during simulated driving: an event-related potential study.

PubMed

Wester, Anne E; Verster, Joris C; Volkerts, Edmund R; Böcker, Koen B E; Kenemans, J Leon

2010-09-01

Driving is a complex task and is susceptible to inattention and distraction. Moreover, alcohol has a detrimental effect on driving performance, possibly due to alcohol-induced attention deficits. The aim of the present study was to assess the effects of alcohol on simulated driving performance and attention orienting and allocation, as assessed by event-related potentials (ERPs). Thirty-two participants completed two test runs in the Divided Attention Steering Simulator (DASS) with blood alcohol concentrations (BACs) of 0.00%, 0.02%, 0.05%, 0.08% and 0.10%. Sixteen participants performed the second DASS test run with a passive auditory oddball to assess alcohol effects on involuntary attention shifting. Sixteen other participants performed the second DASS test run with an active auditory oddball to assess alcohol effects on dual-task performance and active attention allocation. Dose-dependent impairments were found for reaction times, the number of misses and steering error, even more so in dual-task conditions, especially in the active oddball group. ERP amplitudes to novel irrelevant events were also attenuated in a dose-dependent manner. The P3b amplitude to deviant target stimuli decreased with blood alcohol concentration only in the dual-task condition. It is concluded that alcohol increases distractibility and interference from secondary task stimuli, as well as reduces attentional capacity and dual-task integrality.