Asymptomatic radiographic hip osteoarthritis is associated with gait differences, especially in women: A population-based study.

PubMed

Verlinden, Vincentius J A; de Kruijf, Marjolein; Bierma-Zeinstra, Sita M A; Hofman, Albert; Uitterlinden, André G; Ikram, M Arfan; van Meurs, Joyce B J; van der Geest, Jos N

2017-05-01

Hip and knee osteoarthritis (OA) are debilitating diseases that impair gait at severe stages. Although associations between OA and gait are established for normal walking, little is known about its relation with turning and tandem (heel-to-toe) walking. Furthermore, it is unknown how asymptomatic OA associates with gait, and whether associations differ by sex. We investigated how symptomatic and asymptomatic hip and knee OA associate with gait in community-dwelling individuals. In 2706 participants of a population-based cohort study, gait was assessed by electronic walkway and summarised into seven gait domains. Hip and knee radiographs were graded for radiographic OA (ROA) using the Kellgren and Lawrence (K&L) score. Linear regression was used to investigate associations between ROA and gait. Analyses were repeated including only participants with asymptomatic ROA, defined as a K&L-score of 2 without pain. In total, 177 participants (6.5%) had hip ROA and 441 (16.3%) knee ROA. We found no associations of knee ROA with gait. Hip ROA associated with Rhythm, Tandem, and Turning. Furthermore, unilateral hip ROA associated with larger gait asymmetry and gait differences in osteoarthritic and non-osteoarthritic leg, when compared to people without hip ROA. Associations between hip ROA and gait were generally stronger for women than men. Associations for hip ROA remained after restricting to asymptomatic ROA. Hip ROA, but not knee ROA, associates with gait differences in normal walking, turning, and tandem walking in community-dwelling individuals. These associations differ between the sexes, and are already present for asymptomatic ROA. Copyright © 2017 Elsevier B.V. All rights reserved.

Neural Correlates of Communication Skill and Symptom Severity in Autism: A Voxel-Based Morphometry Study

ERIC Educational Resources Information Center

Parks, Lauren K.; Hill, Dina E.; Thoma, Robert J.; Euler, Matthew J.; Lewine, Jeffrey D.; Yeo, Ronald A.

2009-01-01

Although many studies have compared the brains of normal controls and individuals with autism, especially older, higher-functioning individuals with autism, little is known of the neural correlates of the vast clinical heterogeneity characteristic of the disorder. In this study, we used voxel-based morphometry (VBM) to examine gray matter…

Gait recognition based on Gabor wavelets and modified gait energy image for human identification

NASA Astrophysics Data System (ADS)

Huang, Deng-Yuan; Lin, Ta-Wei; Hu, Wu-Chih; Cheng, Chih-Hsiang

2013-10-01

This paper proposes a method for recognizing human identity using gait features based on Gabor wavelets and modified gait energy images (GEIs). Identity recognition by gait generally involves gait representation, extraction, and classification. In this work, a modified GEI convolved with an ensemble of Gabor wavelets is proposed as a gait feature. Principal component analysis is then used to project the Gabor-wavelet-based gait features into a lower-dimension feature space for subsequent classification. Finally, support vector machine classifiers based on a radial basis function kernel are trained and utilized to recognize human identity. The major contributions of this paper are as follows: (1) the consideration of the shadow effect to yield a more complete segmentation of gait silhouettes; (2) the utilization of motion estimation to track people when walkers overlap; and (3) the derivation of modified GEIs to extract more useful gait information. Extensive performance evaluation shows a great improvement of recognition accuracy due to the use of shadow removal, motion estimation, and gait representation using the modified GEIs and Gabor wavelets.

Towards a voxel-based geographic automata for the simulation of geospatial processes

NASA Astrophysics Data System (ADS)

Jjumba, Anthony; Dragićević, Suzana

2016-07-01

Many geographic processes evolve in a three dimensional space and time continuum. However, when they are represented with the aid of geographic information systems (GIS) or geosimulation models they are modelled in a framework of two-dimensional space with an added temporal component. The objective of this study is to propose the design and implementation of voxel-based automata as a methodological approach for representing spatial processes evolving in the four-dimensional (4D) space-time domain. Similar to geographic automata models which are developed to capture and forecast geospatial processes that change in a two-dimensional spatial framework using cells (raster geospatial data), voxel automata rely on the automata theory and use three-dimensional volumetric units (voxels). Transition rules have been developed to represent various spatial processes which range from the movement of an object in 3D to the diffusion of airborne particles and landslide simulation. In addition, the proposed 4D models demonstrate that complex processes can be readily reproduced from simple transition functions without complex methodological approaches. The voxel-based automata approach provides a unique basis to model geospatial processes in 4D for the purpose of improving representation, analysis and understanding their spatiotemporal dynamics. This study contributes to the advancement of the concepts and framework of 4D GIS.

Comparison of the Classifier Oriented Gait Score and the Gait Profile Score based on imitated gait impairments.

PubMed

Christian, Josef; Kröll, Josef; Schwameder, Hermann

2017-06-01

Common summary measures of gait quality such as the Gait Profile Score (GPS) are based on the principle of measuring a distance from the mean pattern of a healthy reference group in a gait pattern vector space. The recently introduced Classifier Oriented Gait Score (COGS) is a pathology specific score that measures this distance in a unique direction, which is indicated by a linear classifier. This approach has potentially improved the discriminatory power to detect subtle changes in gait patterns but does not incorporate a profile of interpretable sub-scores like the GPS. The main aims of this study were to extend the COGS by decomposing it into interpretable sub-scores as realized in the GPS and to compare the discriminative power of the GPS and COGS. Two types of gait impairments were imitated to enable a high level of control of the gait patterns. Imitated impairments were realized by restricting knee extension and inducing leg length discrepancy. The results showed increased discriminatory power of the COGS for differentiating diverse levels of impairment. Comparison of the GPS and COGS sub-scores and their ability to indicate changes in specific variables supports the validity of both scores. The COGS is an overall measure of gait quality with increased power to detect subtle changes in gait patterns and might be well suited for tracing the effect of a therapeutic treatment over time. The newly introduced sub-scores improved the interpretability of the COGS, which is helpful for practical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Research on gait-based human identification

NASA Astrophysics Data System (ADS)

Li, Youguo

Gait recognition refers to automatic identification of individual based on his/her style of walking. This paper proposes a gait recognition method based on Continuous Hidden Markov Model with Mixture of Gaussians(G-CHMM). First, we initialize a Gaussian mix model for training image sequence with K-means algorithm, then train the HMM parameters using a Baum-Welch algorithm. These gait feature sequences can be trained and obtain a Continuous HMM for every person, therefore, the 7 key frames and the obtained HMM can represent each person's gait sequence. Finally, the recognition is achieved by Front algorithm. The experiments made on CASIA gait databases obtain comparatively high correction identification ratio and comparatively strong robustness for variety of bodily angle.

Whole-body voxel-based personalized dosimetry: Multiple voxel S-value approach for heterogeneous media with non-uniform activity distributions.

PubMed

Lee, Min Sun; Kim, Joong Hyun; Paeng, Jin Chul; Kang, Keon Wook; Jeong, Jae Min; Lee, Dong Soo; Lee, Jae Sung

2017-12-14

Personalized dosimetry with high accuracy is becoming more important because of the growing interests in personalized medicine and targeted radionuclide therapy. Voxel-based dosimetry using dose point kernel or voxel S-value (VSV) convolution is available. However, these approaches do not consider medium heterogeneity. Here, we propose a new method for whole-body voxel-based personalized dosimetry for heterogeneous media with non-uniform activity distributions, which is referred to as the multiple VSV approach. Methods: The multiple numbers (N) of VSVs for media with different densities covering the whole-body density ranges were used instead of using only a single VSV for water. The VSVs were pre-calculated using GATE Monte Carlo simulation; those were convoluted with the time-integrated activity to generate density-specific dose maps. Computed tomography-based segmentation was conducted to generate binary maps for each density region. The final dose map was acquired by the summation of N segmented density-specific dose maps. We tested several sets of VSVs with different densities: N = 1 (single water VSV), 4, 6, 8, 10, and 20. To validate the proposed method, phantom and patient studies were conducted and compared with direct Monte Carlo, which was considered the ground truth. Finally, patient dosimetry (10 subjects) was conducted using the multiple VSV approach and compared with the single VSV and organ-based dosimetry approaches. Errors at the voxel- and organ-levels were reported for eight organs. Results: In the phantom and patient studies, the multiple VSV approach showed significant improvements regarding voxel-level errors, especially for the lung and bone regions. As N increased, voxel-level errors decreased, although some overestimations were observed at lung boundaries. In the case of multiple VSVs ( N = 8), we achieved voxel-level errors of 2.06%. In the dosimetry study, our proposed method showed much improved results compared to the single VSV and

Technology-Based Feedback and Its Efficacy in Improving Gait Parameters in Patients with Abnormal Gait: A Systematic Review.

PubMed

Chamorro-Moriana, Gema; Moreno, Antonio José; Sevillano, José Luis

2018-01-06

This systematic review synthesized and analyzed clinical findings related to the effectiveness of innovative technological feedback for tackling functional gait recovery. An electronic search of PUBMED, PEDro, WOS, CINAHL, and DIALNET was conducted from January 2011 to December 2016. The main inclusion criteria were: patients with modified or abnormal gait; application of technology-based feedback to deal with functional recovery of gait; any comparison between different kinds of feedback applied by means of technology, or any comparison between technological and non-technological feedback; and randomized controlled trials. Twenty papers were included. The populations were neurological patients (75%), orthopedic and healthy subjects. All participants were adults, bar one. Four studies used exoskeletons, 6 load platforms and 5 pressure sensors. The breakdown of the type of feedback used was as follows: 60% visual, 40% acoustic and 15% haptic. 55% used terminal feedback versus 65% simultaneous feedback. Prescriptive feedback was used in 60% of cases, while 50% used descriptive feedback. 62.5% and 58.33% of the trials showed a significant effect in improving step length and speed, respectively. Efficacy in improving other gait parameters such as balance or range of movement is observed in more than 75% of the studies with significant outcomes. Treatments based on feedback using innovative technology in patients with abnormal gait are mostly effective in improving gait parameters and therefore useful for the functional recovery of patients. The most frequently highlighted types of feedback were immediate visual feedback followed by terminal and immediate acoustic feedback.

Frontotemporal alterations in pediatric bipolar disorder: results of a voxel-based morphometry study.

PubMed

Dickstein, Daniel P; Milham, Michael P; Nugent, Allison C; Drevets, Wayne C; Charney, Dennis S; Pine, Daniel S; Leibenluft, Ellen

2005-07-01

While numerous magnetic resonance imaging (MRI) studies have evaluated adults with bipolar disorder (BPD), few have examined MRI changes in children with BPD. To determine volume alterations in children with BPD using voxel-based morphometry, an automated MRI analysis method with reduced susceptibility to various biases. A priori regions of interest included amygdala, accumbens, hippocampus, dorsolateral prefrontal cortex (DLPFC), and orbitofrontal cortex. Ongoing study of the pathophysiology of pediatric BPD. Intramural National Institute of Mental Health; approved by the institutional review board. Patients Pediatric subjects with BPD (n = 20) with at least 1 manic or hypomanic episode meeting strict DSM-IV criteria for duration and elevated, expansive mood. Controls (n = 20) and their first-degree relatives lacked psychiatric disorders. Groups were matched for age and sex and did not differ in IQ. With a 1.5-T MRI machine, we collected 1.2-mm axial sections (124 per subject) with an axial 3-dimensional spoiled gradient recalled echo in the steady state sequence. Image analysis was by optimized voxel-based morphometry. Subjects with BPD had reduced gray matter volume in the left DLPFC. With a less conservative statistical threshold, additional gray matter reductions were found in the left accumbens and left amygdala. No difference was found in the hippocampus or orbitofrontal cortex. Our results are consistent with data implicating the prefrontal cortex in emotion regulation, a process that is perturbed in BPD. Reductions in amygdala and accumbens volumes are consistent with neuropsychological data on pediatric BPD. Further study is required to determine the relationship between these findings in children and adults with BPD.

White matter volume loss in amyotrophic lateral sclerosis: A meta-analysis of voxel-based morphometry studies.

PubMed

Chen, Guangxiang; Zhou, Baiwan; Zhu, Hongyan; Kuang, Weihong; Bi, Feng; Ai, Hua; Gu, Zhongwei; Huang, Xiaoqi; Lui, Su; Gong, Qiyong

2018-04-20

Structural neuroimaging studies of white matter (WM) volume in amyotrophic lateral sclerosis (ALS) using voxel-based morphometry (VBM) have yielded inconsistent findings. This study aimed to perform a quantitative voxel-based meta-analysis using effect-size signed differential mapping (ES-SDM) to establish a statistical consensus between published studies for WM volume alterations in ALS. The pooled meta-analysis revealed significant WM volume losses in the bilateral supplementary motor areas (SMAs), bilateral precentral gyri (PGs), left middle cerebellar peduncle and right cerebellum in patients with ALS, involving the corticospinal tract (CST), interhemispheric fibers, subcortical arcuate fibers, projection fibers to the striatum and cortico-ponto-cerebellar tract. The meta-regression showed that the ALS functional rating scale-revised (ALSFRS-R) was positively correlated with decreased WM volume in the bilateral SMAs, whereas illness duration was negatively correlated with WM volume reduction in the right SMA. This study provides a thorough profile of WM volume loss in ALS and robust evidence that ALS is a multisystem neurodegenerative disease that involves a variety of subcortical WM tracts extending beyond motor cortex involvement. Copyright © 2018 Elsevier Inc. All rights reserved.

Technology-Based Feedback and Its Efficacy in Improving Gait Parameters in Patients with Abnormal Gait: A Systematic Review

PubMed Central

Chamorro-Moriana, Gema; Moreno, Antonio José

2018-01-01

This systematic review synthesized and analyzed clinical findings related to the effectiveness of innovative technological feedback for tackling functional gait recovery. An electronic search of PUBMED, PEDro, WOS, CINAHL, and DIALNET was conducted from January 2011 to December 2016. The main inclusion criteria were: patients with modified or abnormal gait; application of technology-based feedback to deal with functional recovery of gait; any comparison between different kinds of feedback applied by means of technology, or any comparison between technological and non-technological feedback; and randomized controlled trials. Twenty papers were included. The populations were neurological patients (75%), orthopedic and healthy subjects. All participants were adults, bar one. Four studies used exoskeletons, 6 load platforms and 5 pressure sensors. The breakdown of the type of feedback used was as follows: 60% visual, 40% acoustic and 15% haptic. 55% used terminal feedback versus 65% simultaneous feedback. Prescriptive feedback was used in 60% of cases, while 50% used descriptive feedback. 62.5% and 58.33% of the trials showed a significant effect in improving step length and speed, respectively. Efficacy in improving other gait parameters such as balance or range of movement is observed in more than 75% of the studies with significant outcomes. Conclusion: Treatments based on feedback using innovative technology in patients with abnormal gait are mostly effective in improving gait parameters and therefore useful for the functional recovery of patients. The most frequently highlighted types of feedback were immediate visual feedback followed by terminal and immediate acoustic feedback. PMID:29316645

Wearable Device-Based Gait Recognition Using Angle Embedded Gait Dynamic Images and a Convolutional Neural Network.

PubMed

Zhao, Yongjia; Zhou, Suiping

2017-02-28

The widespread installation of inertial sensors in smartphones and other wearable devices provides a valuable opportunity to identify people by analyzing their gait patterns, for either cooperative or non-cooperative circumstances. However, it is still a challenging task to reliably extract discriminative features for gait recognition with noisy and complex data sequences collected from casually worn wearable devices like smartphones. To cope with this problem, we propose a novel image-based gait recognition approach using the Convolutional Neural Network (CNN) without the need to manually extract discriminative features. The CNN's input image, which is encoded straightforwardly from the inertial sensor data sequences, is called Angle Embedded Gait Dynamic Image (AE-GDI). AE-GDI is a new two-dimensional representation of gait dynamics, which is invariant to rotation and translation. The performance of the proposed approach in gait authentication and gait labeling is evaluated using two datasets: (1) the McGill University dataset, which is collected under realistic conditions; and (2) the Osaka University dataset with the largest number of subjects. Experimental results show that the proposed approach achieves competitive recognition accuracy over existing approaches and provides an effective parametric solution for identification among a large number of subjects by gait patterns.

Wearable Device-Based Gait Recognition Using Angle Embedded Gait Dynamic Images and a Convolutional Neural Network

PubMed Central

Zhao, Yongjia; Zhou, Suiping

2017-01-01

The widespread installation of inertial sensors in smartphones and other wearable devices provides a valuable opportunity to identify people by analyzing their gait patterns, for either cooperative or non-cooperative circumstances. However, it is still a challenging task to reliably extract discriminative features for gait recognition with noisy and complex data sequences collected from casually worn wearable devices like smartphones. To cope with this problem, we propose a novel image-based gait recognition approach using the Convolutional Neural Network (CNN) without the need to manually extract discriminative features. The CNN’s input image, which is encoded straightforwardly from the inertial sensor data sequences, is called Angle Embedded Gait Dynamic Image (AE-GDI). AE-GDI is a new two-dimensional representation of gait dynamics, which is invariant to rotation and translation. The performance of the proposed approach in gait authentication and gait labeling is evaluated using two datasets: (1) the McGill University dataset, which is collected under realistic conditions; and (2) the Osaka University dataset with the largest number of subjects. Experimental results show that the proposed approach achieves competitive recognition accuracy over existing approaches and provides an effective parametric solution for identification among a large number of subjects by gait patterns. PMID:28264503

A Microsoft Kinect-Based Point-of-Care Gait Assessment Framework for Multiple Sclerosis Patients.

PubMed

Gholami, Farnood; Trojan, Daria A; Kovecses, Jozsef; Haddad, Wassim M; Gholami, Behnood

2017-09-01

Gait impairment is a prevalent and important difficulty for patients with multiple sclerosis (MS), a common neurological disorder. An easy to use tool to objectively evaluate gait in MS patients in a clinical setting can assist clinicians to perform an objective assessment. The overall objective of this study is to develop a framework to quantify gait abnormalities in MS patients using the Microsoft Kinect for the Windows sensor; an inexpensive, easy to use, portable camera. Specifically, we aim to evaluate its feasibility for utilization in a clinical setting, assess its reliability, evaluate the validity of gait indices obtained, and evaluate a novel set of gait indices based on the concept of dynamic time warping. In this study, ten ambulatory MS patients, and ten age and sex-matched normal controls were studied at one session in a clinical setting with gait assessment using a Kinect camera. The expanded disability status scale (EDSS) clinical ambulation score was calculated for the MS subjects, and patients completed the Multiple Sclerosis walking scale (MSWS). Based on this study, we established the potential feasibility of using a Microsoft Kinect camera in a clinical setting. Seven out of the eight gait indices obtained using the proposed method were reliable with intraclass correlation coefficients ranging from 0.61 to 0.99. All eight MS gait indices were significantly different from those of the controls (p-values less than 0.05). Finally, seven out of the eight MS gait indices were correlated with the objective and subjective gait measures (Pearson's correlation coefficients greater than 0.40). This study shows that the Kinect camera is an easy to use tool to assess gait in MS patients in a clinical setting.

[Voxel-Based Morphometry in Autism Spectrum Disorder].

PubMed

Yamasue, Hidenori

2017-05-01

Autism spectrum disorder shows deficits in social communication and interaction including nonverbal communicative behaviors (e.g., eye contact, gestures, voice prosody, and facial expressions) and restricted and repetitive behaviors as its core symptoms. These core symptoms are emerged as an atypical behavioral development in toddlers with the disorder. Atypical neural development is considered to be a neural underpinning of such behaviorally atypical development. A number of studies using voxel-based morphometry have already been conducted to compare regional brain volumes between individuals with autism spectrum disorder and those with typical development. Furthermore, more than ten papers employing meta-analyses of the comparisons using voxel based morphometry between individuals with autism spectrum disorder and those with typical development have already been published. The current review paper adds some brief discussions about potential factors contributing to the inconsistency observed in the previous findings such as difficulty in controlling the confounding effects of different developmental phases among study participants.

Brain volumes in healthy adults aged 40 years and over: a voxel-based morphometry study.

PubMed

Riello, Roberta; Sabattoli, Francesca; Beltramello, Alberto; Bonetti, Matteo; Bono, Giorgio; Falini, Andrea; Magnani, Giuseppe; Minonzio, Giorgio; Piovan, Enrico; Alaimo, Giuseppina; Ettori, Monica; Galluzzi, Samantha; Locatelli, Enrico; Noiszewska, Malgorzata; Testa, Cristina; Frisoni, Giovanni B

2005-08-01

Gender and age effect on brain morphology have been extensively investigated. However, the great variety in methods applied to morphology partly explain the conflicting results of linear patterns of tissue changes and lateral asymmetry in men and women. The aim of the present study was to assess the effect of age, gender and laterality on the volumes of gray matter (GM) and white matter (WM) in a large group of healthy adults by means of voxel-based morphometry. This technique, based on observer-independent algorithms, automatically segments the 3 types of tissue and computes the amount of tissue in each single voxel. Subjects were 229 healthy subjects of 40 years of age or older, who underwent magnetic resonance (MR) for reasons other than cognitive impairment. MR images were reoriented following the AC-PC line and, after removing the voxels below the cerebellum, were processed by Statistical Parametric Mapping (SPM99). GM and WM volumes were normalized for intracranial volume. Women had more fractional GM and WM volumes than men. Age was negatively correlated with both fractional GM and WM, and a gender x age interaction effect was found for WM, men having greater WM loss with advancing age. Pairwise differences between left and right GM were negative (greater GM in right hemisphere) in men, and positive (greater GM in left hemisphere) in women (-0.56+/-4.2 vs 0.99+/-4.8; p=0.019). These results support side-specific accelerated WM loss in men, and may help our better understanding of changes in regional brain structures associated with pathological aging.

Gait recognition based on integral outline

NASA Astrophysics Data System (ADS)

Ming, Guan; Fang, Lv

2017-02-01

Biometric identification technology replaces traditional security technology, which has become a trend, and gait recognition also has become a hot spot of research because its feature is difficult to imitate and theft. This paper presents a gait recognition system based on integral outline of human body. The system has three important aspects: the preprocessing of gait image, feature extraction and classification. Finally, using a method of polling to evaluate the performance of the system, and summarizing the problems existing in the gait recognition and the direction of development in the future.

A voxel-based morphometry study of anosmic patients

PubMed Central

Peng, P; Xiao, W; Si, L F; Wang, J F; Wang, S K; Zhai, R Y; Wei, Y X

2013-01-01

Objective: The aim of our study was to compare volume change in grey matter (GM) and white matter (WM) in a group of subjects with anosmia and a healthy control group. We tried to find a regular pattern of atrophy within and between GM and WM and to determine whether any particular areas are more sensitive to olfactory injury. Methods: There were 19 anosmic patients and 20 age- and sex-matched control subjects. We acquired MR images on a 3-T scanner and performed voxel-based morphometry using the VBM8 toolbox and SPM8 in a MATLAB® (MathWorks®, Natick, MA) environment. Results: Patients with anosmia showed a significant decrease in GM volume, mainly in the anterior cingulate cortex, middle temporal gyrus, superior temporal gyrus, fusiform gyrus, supramarginal gyrus, superior frontal gyrus, middle frontal gyrus, middle occipital gyrus, anterior insular cortex and cerebellum. In addition, we observed volume decreases in smaller areas such as the piriform cortex, the inferior temporal gyrus, the precuneus and the subcallosal gyrus. All WM areas with atrophy were near those GM areas that experienced volume loss. There was more volume atrophy in GM areas corresponding to WM areas with more volume loss. Atrophy increased with disease duration. Conclusion: There is simultaneous atrophy in GM and WM, and the degree of atrophy is greater with longer disease duration. Different GM and WM areas have different sensitivities to olfactory injury. Advances in knowledge: This study examines the atrophy pattern in and between GM and WM—a subject that has not been widely researched previously. PMID:24133057

Factors associated with lower gait speed among the elderly living in a developing country: a cross-sectional population-based study.

PubMed

Busch, Telma de Almeida; Duarte, Yeda Aparecida; Pires Nunes, Daniella; Lebrão, Maria Lucia; Satya Naslavsky, Michel; dos Santos Rodrigues, Anelise; Amaro, Edson

2015-04-01

Among community-dwelling older adults, mean values for gait speed vary substantially depending not only on the population studied, but also on the methodology used. Despite the large number of studies published in developed countries, there are few population-based studies in developing countries with socioeconomic inequality and different health conditions, and this is the first study with a representative sample of population. To explore this, the association of lower gait speed with sociodemographic, anthropometric factors, mental status and physical health was incorporated participants' weight (main weight) in the analysis of population of community-dwelling older adults living in a developing country. This was a cross-sectional population based on a sample of 1112 older adults aged 60 years and over from Health, Wellbeing and Aging Study cohort 2010. Usual gait speed (s) to walk 3 meters was stratified by sex and height into quartiles. Multiple regression analysis was performed to investigate the independent effect of each factor associated with a slower usual gait speed. The average walking speed of the elderly was 0.81 m/s-0.78 m/s among women and 0.86 m/s among men. In the final model, the factors associated with lower gait speed were age (OR = 3.56), literacy (OR = 3.20), difficulty in one or more IADL (OR = 2.74), presence of cardiovascular disease (OR = 2.15) and sedentarism. When we consider the 50% slower, we can add the variables handgrip strength, and the presence of COPD. Gait speed is a clinical marker and an important measure of functional capacity among the elderly. Our findings suggest that lower walking speed is associated with age, education, but especially with modifiable factors such as impairment of IADL, physical inactivity and cardiovascular disease. These results reinforce how important it is for the elderly to remain active and healthy.

Class Energy Image Analysis for Video Sensor-Based Gait Recognition: A Review

PubMed Central

Lv, Zhuowen; Xing, Xianglei; Wang, Kejun; Guan, Donghai

2015-01-01

Gait is a unique perceptible biometric feature at larger distances, and the gait representation approach plays a key role in a video sensor-based gait recognition system. Class Energy Image is one of the most important gait representation methods based on appearance, which has received lots of attentions. In this paper, we reviewed the expressions and meanings of various Class Energy Image approaches, and analyzed the information in the Class Energy Images. Furthermore, the effectiveness and robustness of these approaches were compared on the benchmark gait databases. We outlined the research challenges and provided promising future directions for the field. To the best of our knowledge, this is the first review that focuses on Class Energy Image. It can provide a useful reference in the literature of video sensor-based gait representation approach. PMID:25574935

A Corner-Point-Grid-Based Voxelization Method for Complex Geological Structure Model with Folds

NASA Astrophysics Data System (ADS)

Chen, Qiyu; Mariethoz, Gregoire; Liu, Gang

2017-04-01

3D voxelization is the foundation of geological property modeling, and is also an effective approach to realize the 3D visualization of the heterogeneous attributes in geological structures. The corner-point grid is a representative data model among all voxel models, and is a structured grid type that is widely applied at present. When carrying out subdivision for complex geological structure model with folds, we should fully consider its structural morphology and bedding features to make the generated voxels keep its original morphology. And on the basis of which, they can depict the detailed bedding features and the spatial heterogeneity of the internal attributes. In order to solve the shortage of the existing technologies, this work puts forward a corner-point-grid-based voxelization method for complex geological structure model with folds. We have realized the fast conversion from the 3D geological structure model to the fine voxel model according to the rule of isocline in Ramsay's fold classification. In addition, the voxel model conforms to the spatial features of folds, pinch-out and other complex geological structures, and the voxels of the laminas inside a fold accords with the result of geological sedimentation and tectonic movement. This will provide a carrier and model foundation for the subsequent attribute assignment as well as the quantitative analysis and evaluation based on the spatial voxels. Ultimately, we use examples and the contrastive analysis between the examples and the Ramsay's description of isoclines to discuss the effectiveness and advantages of the method proposed in this work when dealing with the voxelization of 3D geologic structural model with folds based on corner-point grids.

A voxel visualization and analysis system based on AutoCAD

NASA Astrophysics Data System (ADS)

Marschallinger, Robert

1996-05-01

A collection of AutoLISP programs is presented which enable the visualization and analysis of voxel models by AutoCAD rel. 12/rel. 13. The programs serve as an interactive, graphical front end for manipulating the results of three-dimensional modeling software producing block estimation data. ASCII data files describing geometry and attributes per estimation block are imported and stored as a voxel array. Each voxel may contain multiple attributes, therefore different parameters may be incorporated in one voxel array. Voxel classification is implemented on a layer basis providing flexible treatment of voxel classes such as recoloring, peeling, or volumetry. A versatile clipping tool enables slicing voxel arrays according to combinations of three perpendicular clipping planes. The programs feature an up-to-date, graphical user interface for user-friendly operation by non AutoCAD specialists.

The development and validity of the Salford Gait Tool: an observation-based clinical gait assessment tool.

PubMed

Toro, Brigitte; Nester, Christopher J; Farren, Pauline C

2007-03-01

To develop the construct, content, and criterion validity of the Salford Gait Tool (SF-GT) and to evaluate agreement between gait observations using the SF-GT and kinematic gait data. Tool development and comparative evaluation. University in the United Kingdom. For designing construct and content validity, convenience samples of 10 children with hemiplegic, diplegic, and quadriplegic cerebral palsy (CP) and 152 physical therapy students and 4 physical therapists were recruited. For developing criterion validity, kinematic gait data of 13 gait clusters containing 56 children with hemiplegic, diplegic, and quadriplegic CP and 11 neurologically intact children was used. For clinical evaluation, a convenience sample of 23 pediatric physical therapists participated. We developed a sagittal plane observational gait assessment tool through a series of design, test, and redesign iterations. The tool's grading system was calibrated using kinematic gait data of 13 gait clusters and was evaluated by comparing the agreement of gait observations using the SF-GT with kinematic gait data. Criterion standard kinematic gait data. There was 58% mean agreement based on grading categories and 80% mean agreement based on degree estimations evaluated with the least significant difference method. The new SF-GT has good concurrent criterion validity.

Sexual differentiation of the adolescent rat brain: A longitudinal voxel-based morphometry study.

PubMed

Sumiyoshi, Akira; Nonaka, Hiroi; Kawashima, Ryuta

2017-03-06

The sexual differentiation of the rat brain during the adolescent period has been well documented in post-mortem histological studies. However, to further understand the morphological changes occurring in the entire brain, a noninvasive neuroimaging method allowing an unbiased, comprehensive, and longitudinal investigation of brain morphology should be used. In this study, we investigated the sexual differentiation of the rat brain during the adolescent period using longitudinal voxel-based morphometry (VBM) analysis. Male and female Wistar rats (n=12 of each) were scanned in a 7.0-T MRI scanner at five time points from 6 to 10 weeks of age. The T2-weighted MRI images were segmented using the rat brain tissue priors that have been published by our laboratory. At the global level, the results of the VBM analysis showed greater increases in total gray matter volume in the males during the adolescent period, although we did not find significant differences in total white matter volume. At the voxel level, we found significant increases in the regional gray matter volume of the occipital cortex, amygdala, hippocampal formation, and cerebellum. At the regional level, only the occipital cortex in the females exhibited decreases during the adolescent period. These results were, at least in part, consistent with those of previous longitudinal VBM studies in humans, thus providing translational evidence of the sexual differentiation of the developing brain between rodents and humans. Copyright © 2017 Elsevier B.V. All rights reserved.

Sensitivity study of voxel-based PET image comparison to image registration algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yip, Stephen, E-mail: syip@lroc.harvard.edu; Chen, Aileen B.; Berbeco, Ross

2014-11-01

Purpose: Accurate deformable registration is essential for voxel-based comparison of sequential positron emission tomography (PET) images for proper adaptation of treatment plan and treatment response assessment. The comparison may be sensitive to the method of deformable registration as the optimal algorithm is unknown. This study investigated the impact of registration algorithm choice on therapy response evaluation. Methods: Sixteen patients with 20 lung tumors underwent a pre- and post-treatment computed tomography (CT) and 4D FDG-PET scans before and after chemoradiotherapy. All CT images were coregistered using a rigid and ten deformable registration algorithms. The resulting transformations were then applied to themore » respective PET images. Moreover, the tumor region defined by a physician on the registered PET images was classified into progressor, stable-disease, and responder subvolumes. Particularly, voxels with standardized uptake value (SUV) decreases >30% were classified as responder, while voxels with SUV increases >30% were progressor. All other voxels were considered stable-disease. The agreement of the subvolumes resulting from difference registration algorithms was assessed by Dice similarity index (DSI). Coefficient of variation (CV) was computed to assess variability of DSI between individual tumors. Root mean square difference (RMS{sub rigid}) of the rigidly registered CT images was used to measure the degree of tumor deformation. RMS{sub rigid} and DSI were correlated by Spearman correlation coefficient (R) to investigate the effect of tumor deformation on DSI. Results: Median DSI{sub rigid} was found to be 72%, 66%, and 80%, for progressor, stable-disease, and responder, respectively. Median DSI{sub deformable} was 63%–84%, 65%–81%, and 82%–89%. Variability of DSI was substantial and similar for both rigid and deformable algorithms with CV > 10% for all subvolumes. Tumor deformation had moderate to significant impact on DSI for

New Lower-Limb Gait Asymmetry Indices Based on a Depth Camera

PubMed Central

Auvinet, Edouard; Multon, Franck; Meunier, Jean

2015-01-01

Background: Various asymmetry indices have been proposed to compare the spatiotemporal, kinematic and kinetic parameters of lower limbs during the gait cycle. However, these indices rely on gait measurement systems that are costly and generally require manual examination, calibration procedures and the precise placement of sensors/markers on the body of the patient. Methods: To overcome these issues, this paper proposes a new asymmetry index, which uses an inexpensive, easy-to-use and markerless depth camera (Microsoft Kinect™) output. This asymmetry index directly uses depth images provided by the Kinect™ without requiring joint localization. It is based on the longitudinal spatial difference between lower-limb movements during the gait cycle. To evaluate the relevance of this index, fifteen healthy subjects were tested on a treadmill walking normally and then via an artificially-induced gait asymmetry with a thick sole placed under one shoe. The gait movement was simultaneously recorded using a Kinect™ placed in front of the subject and a motion capture system. Results: The proposed longitudinal index distinguished asymmetrical gait (p < 0.001), while other symmetry indices based on spatiotemporal gait parameters failed using such Kinect™ skeleton measurements. Moreover, the correlation coefficient between this index measured by Kinect™ and the ground truth of this index measured by motion capture is 0.968. Conclusion: This gait asymmetry index measured with a Kinect™ is low cost, easy to use and is a promising development for clinical gait analysis. PMID:25719863

Two-dimensional PCA-based human gait identification

NASA Astrophysics Data System (ADS)

Chen, Jinyan; Wu, Rongteng

2012-11-01

It is very necessary to recognize person through visual surveillance automatically for public security reason. Human gait based identification focus on recognizing human by his walking video automatically using computer vision and image processing approaches. As a potential biometric measure, human gait identification has attracted more and more researchers. Current human gait identification methods can be divided into two categories: model-based methods and motion-based methods. In this paper a two-Dimensional Principal Component Analysis and temporal-space analysis based human gait identification method is proposed. Using background estimation and image subtraction we can get a binary images sequence from the surveillance video. By comparing the difference of two adjacent images in the gait images sequence, we can get a difference binary images sequence. Every binary difference image indicates the body moving mode during a person walking. We use the following steps to extract the temporal-space features from the difference binary images sequence: Projecting one difference image to Y axis or X axis we can get two vectors. Project every difference image in the difference binary images sequence to Y axis or X axis difference binary images sequence we can get two matrixes. These two matrixes indicate the styles of one walking. Then Two-Dimensional Principal Component Analysis(2DPCA) is used to transform these two matrixes to two vectors while at the same time keep the maximum separability. Finally the similarity of two human gait images is calculated by the Euclidean distance of the two vectors. The performance of our methods is illustrated using the CASIA Gait Database.

Design and Validation of a Radio-Frequency Identification-Based Device for Routinely Assessing Gait Speed in a Geriatrics Clinic.

PubMed

Barry, Lisa C; Hatchman, Laura; Fan, Zhaoyan; Guralnik, Jack M; Gao, Robert X; Kuchel, George A

2018-05-01

To evaluate the feasibility, acceptability, and validity of a radio-frequency identification (RFID)-based system to measure gait speed in a clinical setting as a first step to using unobtrusive gait speed assessment in routine clinical care. Feasibility study comparing gait speed assessed using an RFID-based system with gait speed assessed using handheld stopwatch, the criterion standard. Outpatient geriatrics clinic at a Connecticut-based academic medical center. Clinic attendees who could walk independently with or without an assistive device (N=50) and healthcare providers (N=9). Gait speed was measured in twice using 2 methods each time before participants entered an examination room. Participants walked at their usual pace while gait speed was recorded simultaneously using the RFID-based system and a handheld stopwatch operated by a trained study investigator. After 2 trials, participants completed a brief survey regarding their experience. At the end of the study period, clinic healthcare providers completed a separate survey. Test-retest reliability of the RFID-based system was high (intraclass correlation coefficient = 0.953). The mean difference ± standard deviation in gait speed between the RFID-based system and the stopwatch was -0.003±0.035 m/s (p=.53) and did not differ significantly according to age, sex, or use of an assistive walking aid. Acceptability of the device was high, and 8 of 9 providers indicated that measuring gait speed using the RFID-based system should be a part of routine clinical care. RFID technology may offer a practical means of overcoming barriers to routine measurement of gait speed in real-world outpatient clinical settings. © 2018, Copyright the Authors Journal compilation © 2018, The American Geriatrics Society.

Clinical usefulness of augmented reality using infrared camera based real-time feedback on gait function in cerebral palsy: a case study

PubMed Central

Lee, Byoung-Hee

2016-01-01

[Purpose] This study investigated the effects of real-time feedback using infrared camera recognition technology-based augmented reality in gait training for children with cerebral palsy. [Subjects] Two subjects with cerebral palsy were recruited. [Methods] In this study, augmented reality based real-time feedback training was conducted for the subjects in two 30-minute sessions per week for four weeks. Spatiotemporal gait parameters were used to measure the effect of augmented reality-based real-time feedback training. [Results] Velocity, cadence, bilateral step and stride length, and functional ambulation improved after the intervention in both cases. [Conclusion] Although additional follow-up studies of the augmented reality based real-time feedback training are required, the results of this study demonstrate that it improved the gait ability of two children with cerebral palsy. These findings suggest a variety of applications of conservative therapeutic methods which require future clinical trials. PMID:27190489

Clinical usefulness of augmented reality using infrared camera based real-time feedback on gait function in cerebral palsy: a case study.

PubMed

Lee, Byoung-Hee

2016-04-01

[Purpose] This study investigated the effects of real-time feedback using infrared camera recognition technology-based augmented reality in gait training for children with cerebral palsy. [Subjects] Two subjects with cerebral palsy were recruited. [Methods] In this study, augmented reality based real-time feedback training was conducted for the subjects in two 30-minute sessions per week for four weeks. Spatiotemporal gait parameters were used to measure the effect of augmented reality-based real-time feedback training. [Results] Velocity, cadence, bilateral step and stride length, and functional ambulation improved after the intervention in both cases. [Conclusion] Although additional follow-up studies of the augmented reality based real-time feedback training are required, the results of this study demonstrate that it improved the gait ability of two children with cerebral palsy. These findings suggest a variety of applications of conservative therapeutic methods which require future clinical trials.

Impact of voxel size variation on CBCT-based diagnostic outcome in dentistry: a systematic review.

PubMed

Spin-Neto, Rubens; Gotfredsen, Erik; Wenzel, Ann

2013-08-01

The objective of this study was to make a systematic review on the impact of voxel size in cone beam computed tomography (CBCT)-based image acquisition, retrieving evidence regarding the diagnostic outcome of those images. The MEDLINE bibliographic database was searched from 1950 to June 2012 for reports comparing diverse CBCT voxel sizes. The search strategy was limited to English-language publications using the following combined terms in the search strategy: (voxel or FOV or field of view or resolution) and (CBCT or cone beam CT). The results from the review identified 20 publications that qualitatively or quantitatively assessed the influence of voxel size on CBCT-based diagnostic outcome, and in which the methodology/results comprised at least one of the expected parameters (image acquisition, reconstruction protocols, type of diagnostic task, and presence of a gold standard). The diagnostic task assessed in the studies was diverse, including the detection of root fractures, the detection of caries lesions, and accuracy of 3D surface reconstruction and of bony measurements, among others. From the studies assessed, it is clear that no general protocol can be yet defined for CBCT examination of specific diagnostic tasks in dentistry. Rationale in this direction is an important step to define the utility of CBCT imaging.

Prevalence and Burden of Gait Disorders in Elderly Men and Women Aged 60–97 Years: A Population-Based Study

PubMed Central

Mahlknecht, Philipp; Kiechl, Stefan; Bloem, Bastiaan R.; Willeit, Johann; Scherfler, Christoph; Gasperi, Arno; Rungger, Gregorio; Poewe, Werner; Seppi, Klaus

2013-01-01

Background Although gait disorders are common in the elderly, the prevalence and overall burden of these disorders in the general community is not well defined. Methods In a cross-sectional investigation of the population-based Bruneck Study cohort, 488 community-residing elderly aged 60–97 years underwent a thorough neurological assessment including a standardized gait evaluation. Gait disorders were classified according to an accepted scheme and their associations to falls, neuropsychological measures, and quality of life were explored. Results Overall, 32.2% (95% confidence interval [CI] 28.2%–36.4%) of participants presented with impaired gait. Prevalence increased with age (p<0.001), but 38.3% (95%CI 30.1%–47.3%) of the subjects aged 80 years or older still had a normally preserved gait. A total of 24.0% (95%CI 20.4%–28.0%) manifested neurological gait disorders, 17.4% (14.3%–21.0%) non-neurological gait problems, and 9.2% (6.9%–12.1%) a combination of both. While there was no association of neurological gait disorders with gender, non-neurological gait disorders were more frequent in women (p = 0.012). Within the group of neurological gait disorders 69.2% (95%CI 60.3%–76.9%) had a single distinct entity and 30.8% (23.1%–39.7%) had multiple neurological causes for gait impairment. Gait disorders had a significant negative impact on quantitative gait measures, but only neurological gait disorders were associated with recurrent falls (odds ratio 3.3; 95%CI 1.4–7.5; p = 0.005 for single and 7.1; 2.7–18.7; p<0.001 for multiple neurological gait disorders). Finally, we detected a significant association of gait disorders, in particular neurological gait disorders, with depressed mood, cognitive dysfunction, and compromised quality of life. Conclusions Gait disorders are common in the general elderly population and are associated with reduced mobility. Neurological gait disorders in particular are associated with recurrent falls, lower

Bipedal gait model for precise gait recognition and optimal triggering in foot drop stimulator: a proof of concept.

PubMed

Shaikh, Muhammad Faraz; Salcic, Zoran; Wang, Kevin I-Kai; Hu, Aiguo Patrick

2018-03-10

Electrical stimulators are often prescribed to correct foot drop walking. However, commercial foot drop stimulators trigger inappropriately under certain non-gait scenarios. Past researches addressed this limitation by defining stimulation control based on automaton of a gait cycle executed by foot drop of affected limb/foot only. Since gait is a collaborative activity of both feet, this research highlights the role of normal foot for robust gait detection and stimulation triggering. A novel bipedal gait model is proposed where gait cycle is realized as an automaton based on concurrent gait sub-phases (states) from each foot. The input for state transition is fused information from feet-worn pressure and inertial sensors. Thereafter, a bipedal gait model-based stimulation control algorithm is developed. As a feasibility study, bipedal gait model and stimulation control are evaluated in real-time simulation manner on normal and simulated foot drop gait measurements from 16 able-bodied participants with three speed variations, under inappropriate triggering scenarios and with foot drop rehabilitation exercises. Also, the stimulation control employed in commercial foot drop stimulators and single foot gait-based foot drop stimulators are compared alongside. Gait detection accuracy (98.9%) and precise triggering under all investigations prove bipedal gait model reliability. This infers that gait detection leveraging bipedal periodicity is a promising strategy to rectify prevalent stimulation triggering deficiencies in commercial foot drop stimulators. Graphical abstract Bipedal information-based gait recognition and stimulation triggering.

A Voxel-Based Approach for Imaging Voids in Three-Dimensional Point Clouds

NASA Astrophysics Data System (ADS)

Salvaggio, Katie N.

Geographically accurate scene models have enormous potential beyond that of just simple visualizations in regard to automated scene generation. In recent years, thanks to ever increasing computational efficiencies, there has been significant growth in both the computer vision and photogrammetry communities pertaining to automatic scene reconstruction from multiple-view imagery. The result of these algorithms is a three-dimensional (3D) point cloud which can be used to derive a final model using surface reconstruction techniques. However, the fidelity of these point clouds has not been well studied, and voids often exist within the point cloud. Voids exist in texturally difficult areas, as well as areas where multiple views were not obtained during collection, constant occlusion existed due to collection angles or overlapping scene geometry, or in regions that failed to triangulate accurately. It may be possible to fill in small voids in the scene using surface reconstruction or hole-filling techniques, but this is not the case with larger more complex voids, and attempting to reconstruct them using only the knowledge of the incomplete point cloud is neither accurate nor aesthetically pleasing. A method is presented for identifying voids in point clouds by using a voxel-based approach to partition the 3D space. By using collection geometry and information derived from the point cloud, it is possible to detect unsampled voxels such that voids can be identified. This analysis takes into account the location of the camera and the 3D points themselves to capitalize on the idea of free space, such that voxels that lie on the ray between the camera and point are devoid of obstruction, as a clear line of sight is a necessary requirement for reconstruction. Using this approach, voxels are classified into three categories: occupied (contains points from the point cloud), free (rays from the camera to the point passed through the voxel), and unsampled (does not contain points

A biofeedback cycling training to improve locomotion: a case series study based on gait pattern classification of 153 chronic stroke patients.

PubMed

Ferrante, Simona; Ambrosini, Emilia; Ravelli, Paola; Guanziroli, Eleonora; Molteni, Franco; Ferrigno, Giancarlo; Pedrocchi, Alessandra

2011-08-24

The restoration of walking ability is the main goal of post-stroke lower limb rehabilitation and different studies suggest that pedaling may have a positive effect on locomotion. The aim of this study was to explore the feasibility of a biofeedback pedaling treatment and its effects on cycling and walking ability in chronic stroke patients. A case series study was designed and participants were recruited based on a gait pattern classification of a population of 153 chronic stroke patients. In order to optimize participants selection, a k-means cluster analysis was performed to subgroup homogenous gait patterns in terms of gait speed and symmetry.The training consisted of a 2-week treatment of 6 sessions. A visual biofeedback helped the subjects in maintaining a symmetrical contribution of the two legs during pedaling. Participants were assessed before, after training and at follow-up visits (one week after treatment). Outcome measures were the unbalance during a pedaling test, and the temporal, spatial, and symmetry parameters during gait analysis. Three clusters, mainly differing in terms of gait speed, were identified and participants, representative of each cluster, were selected.An intra-subject statistical analysis (ANOVA) showed that all patients significantly decreased the pedaling unbalance after treatment and maintained significant improvements with respect to baseline at follow-up. The 2-week treatment induced some modifications in the gait pattern of two patients: one, the most impaired, significantly improved mean velocity and increased gait symmetry; the other one reduced significantly the over-compensation of the healthy limb. No benefits were produced in the gait of the last subject who maintained her slow but almost symmetrical pattern. Thus, this study might suggest that the treatment can be beneficial for patients having a very asymmetrical and inefficient gait and for those that overuse the healthy leg. The results demonstrated that the treatment

A biofeedback cycling training to improve locomotion: a case series study based on gait pattern classification of 153 chronic stroke patients

PubMed Central

2011-01-01

Background The restoration of walking ability is the main goal of post-stroke lower limb rehabilitation and different studies suggest that pedaling may have a positive effect on locomotion. The aim of this study was to explore the feasibility of a biofeedback pedaling treatment and its effects on cycling and walking ability in chronic stroke patients. A case series study was designed and participants were recruited based on a gait pattern classification of a population of 153 chronic stroke patients. Methods In order to optimize participants selection, a k-means cluster analysis was performed to subgroup homogenous gait patterns in terms of gait speed and symmetry. The training consisted of a 2-week treatment of 6 sessions. A visual biofeedback helped the subjects in maintaining a symmetrical contribution of the two legs during pedaling. Participants were assessed before, after training and at follow-up visits (one week after treatment). Outcome measures were the unbalance during a pedaling test, and the temporal, spatial, and symmetry parameters during gait analysis. Results and discussion Three clusters, mainly differing in terms of gait speed, were identified and participants, representative of each cluster, were selected. An intra-subject statistical analysis (ANOVA) showed that all patients significantly decreased the pedaling unbalance after treatment and maintained significant improvements with respect to baseline at follow-up. The 2-week treatment induced some modifications in the gait pattern of two patients: one, the most impaired, significantly improved mean velocity and increased gait symmetry; the other one reduced significantly the over-compensation of the healthy limb. No benefits were produced in the gait of the last subject who maintained her slow but almost symmetrical pattern. Thus, this study might suggest that the treatment can be beneficial for patients having a very asymmetrical and inefficient gait and for those that overuse the healthy leg

Does dance-based therapy increase gait speed in older adults with chronic lower extremity pain: a feasibility study.

PubMed

Krampe, Jean; Wagner, Joanne M; Hawthorne, Kelly; Sanazaro, Deborah; Wong-Anuchit, Choochart; Budhathoki, Chakra; Lorenz, Rebecca A; Raaf, Soren

2014-01-01

A decreased gait speed in older adults can lead to dependency when the individuals are no longer able to participate in activities or do things for themselves. Thirty-seven senior apartment residents (31 females; Mean age=80.6 years; SD=8.9) with lower extremity pain/stiffness participated in a feasibility and preliminary efficacy study of 12 weeks (24 sessions). Healthy-Steps dance therapy compared to a wait-list control group. Small improvements in gait speed ([ES]=0.33) were noted for participants completing 19-24 dance sessions. Improvements in gait speed measured by a 10 Meter Walk Test (0.0517 m/s) exceeded 0.05 m/s, a value deemed to be meaningful in community dwelling older adults. These feasibility study findings support the need for additional research using dance-based therapy for older adults with lower extremity pain. Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of 6-month community-based exercise interventions on gait and functional fitness of an older population: a quasi-experimental study.

PubMed

Ramalho, Fátima; Santos-Rocha, Rita; Branco, Marco; Moniz-Pereira, Vera; André, Helô-Isa; Veloso, António P; Carnide, Filomena

2018-01-01

Gait ability in older adults has been associated with independent living, increased survival rates, fall prevention, and quality of life. There are inconsistent findings regarding the effects of exercise interventions in the maintenance of gait parameters. The aim of the study was to analyze the effects of a community-based periodized exercise intervention on the improvement of gait parameters and functional fitness in an older adult group compared with a non-periodized program. A quasi-experimental study with follow-up was performed in a periodized exercise group (N=15) and in a non-periodized exercise group (N=13). The primary outcomes were plantar pressure gait parameters, and the secondary outcomes were physical activity, aerobic endurance, lower limb strength, agility, and balance. These variables were recorded at baseline and after 6 months of intervention. Both programs were tailored to older adults' functional fitness level and proved to be effective in reducing the age-related decline regarding functional fitness and gait parameters. Gait parameters were sensitive to both the exercise interventions. These exercise protocols can be used by exercise professionals in prescribing community exercise programs, as well as by health professionals in promoting active aging.

Model Predictive Control-based gait pattern generation for wearable exoskeletons.

PubMed

Wang, Letian; van Asseldonk, Edwin H F; van der Kooij, Herman

2011-01-01

This paper introduces a new method for controlling wearable exoskeletons that do not need predefined joint trajectories. Instead, it only needs basic gait descriptors such as step length, swing duration, and walking speed. End point Model Predictive Control (MPC) is used to generate the online joint trajectories based on these gait parameters. Real-time ability and control performance of the method during the swing phase of gait cycle is studied in this paper. Experiments are performed by helping a human subject swing his leg with different patterns in the LOPES gait trainer. Results show that the method is able to assist subjects to make steps with different step length and step duration without predefined joint trajectories and is fast enough for real-time implementation. Future study of the method will focus on controlling the exoskeletons in the entire gait cycle. © 2011 IEEE

The impact of sample size on the reproducibility of voxel-based lesion-deficit mappings.

PubMed

Lorca-Puls, Diego L; Gajardo-Vidal, Andrea; White, Jitrachote; Seghier, Mohamed L; Leff, Alexander P; Green, David W; Crinion, Jenny T; Ludersdorfer, Philipp; Hope, Thomas M H; Bowman, Howard; Price, Cathy J

2018-07-01

This study investigated how sample size affects the reproducibility of findings from univariate voxel-based lesion-deficit analyses (e.g., voxel-based lesion-symptom mapping and voxel-based morphometry). Our effect of interest was the strength of the mapping between brain damage and speech articulation difficulties, as measured in terms of the proportion of variance explained. First, we identified a region of interest by searching on a voxel-by-voxel basis for brain areas where greater lesion load was associated with poorer speech articulation using a large sample of 360 right-handed English-speaking stroke survivors. We then randomly drew thousands of bootstrap samples from this data set that included either 30, 60, 90, 120, 180, or 360 patients. For each resample, we recorded effect size estimates and p values after conducting exactly the same lesion-deficit analysis within the previously identified region of interest and holding all procedures constant. The results show (1) how often small effect sizes in a heterogeneous population fail to be detected; (2) how effect size and its statistical significance varies with sample size; (3) how low-powered studies (due to small sample sizes) can greatly over-estimate as well as under-estimate effect sizes; and (4) how large sample sizes (N ≥ 90) can yield highly significant p values even when effect sizes are so small that they become trivial in practical terms. The implications of these findings for interpreting the results from univariate voxel-based lesion-deficit analyses are discussed. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Deviations in gait metrics in patients with chronic ankle instability: a case control study.

PubMed

Gigi, Roy; Haim, Amir; Luger, Elchanan; Segal, Ganit; Melamed, Eyal; Beer, Yiftah; Nof, Matityahu; Nyska, Meir; Elbaz, Avi

2015-01-01

Gait metric alterations have been previously reported in patients suffering from chronic ankle instability (CAI). Previous studies of gait in this population have been comprised of relatively small cohorts, and the findings of these studies are not uniform. The objective of the present study was to examine spatiotemporal gait metrics in patients with CAI and examine the relationship between self-reported disease severity and the magnitude of gait abnormalities. Forty-four patients with CAI were identified and compared to 53 healthy controls. Patients were evaluated with spatiotemporal gait analysis via a computerized mat and with the Short Form (SF) - 36 health survey. Patients with CAI were found to walk with approximately 16% slower walking velocity, 9% lower cadence and approximately 7% lower step length. Furthermore, the base of support, during walking, in the CAI group was approximately 43% wider, and the single limb support phase was 3.5% shorter compared to the control group. All of the SF-36 8-subscales, as well as the SF-36 physical component summary and SF-36 mental component summary, were significantly lower in patients with CAI compared to the control group. Finally, significant correlations were found between most of the objective gait measures and the SF-36 mental component summary and SF-36 physical component summary. The results outline a gait profile for patients suffering from CAI. Significant differences were found in most spatiotemporal gait metrics. An important finding was a significantly wider base of support. It may be speculated that these gait alterations may reflect a strategy to deal with imbalance and pain. These findings suggest the usefulness of gait metrics, alongside with the use of self-evaluation questionnaires, in assessing disease severity of patients with CAI.

Lesion location associated with balance recovery and gait velocity change after rehabilitation in stroke patients.

PubMed

Moon, Hyun Im; Lee, Hyo Jeong; Yoon, Seo Yeon

2017-06-01

Impaired gait function after stroke contributes strongly to overall patient disability. However, the response to rehabilitation varies between individuals. The aims of this study were to identify predictors of gait velocity change and to elucidate lesion location associated with change of balance and gait function. We reviewed 102 stroke patients. The patients were divided into two groups according to gait ability post-rehabilitation, and we analyzed differences in their characteristics, such as demographic information, lesion factors, and initial balance function. Multivariate regression analyses were performed to examine the predictors of rehabilitation response. Lesion location and volume were measured on brain magnetic resonance images. We generated statistical maps of the lesions related to functional gains in gait and balance using voxel-based lesion symptom mapping (VLSM). The group of patients who regained independent ambulation function showed a smaller lesion size, a shorter duration from stroke onset, and higher initial balance function. In the regression model, gait velocity changes were predicted with the initial Berg balance scale (BBS) and duration post-onset. Absolute BBS changes were also correlated with the duration post-onset and initial BBS, and relative BBS changes were predicted by the baseline BBS. Using VLSM, lesion locations associated with gait velocity changes and balance adjusting for other factors were the insula, internal capsule, and adjacent white matter. Initial balance function as well as the interval between stroke onset and the initiation of therapy might influence balance recovery and gait velocity changes. Damage to the insula and internal capsule also affected gait velocity change after rehabilitation.

TU-F-CAMPUS-J-04: Impact of Voxel Anisotropy On Statistic Texture Features of Oncologic PET: A Simulation Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, F; Byrd, D; Bowen, S

2015-06-15

Purpose: Texture metrics extracted from oncologic PET have been investigated with respect to their usefulness as definitive indicants for prognosis in a variety of cancer. Metric calculation is often based on cubic voxels. Most commonly used PET scanners, however, produce rectangular voxels, which may change texture metrics. The objective of this study was to examine the variability of PET texture feature metrics resulting from voxel anisotropy. Methods: Sinograms of NEMA NU-2 phantom for 18F-FDG were simulated using the ASIM simulation tool. The obtained projection data was reconstructed (3D-OSEM) on grids of cubic and rectangular voxels, producing PET images of resolutionmore » of 2.73x2.73x3.27mm3 and 3.27x3.27x3.27mm3, respectively. An interpolated dataset obtained from resampling the rectangular voxel data for isotropic voxel dimension (3.27mm) was also considered. For each image dataset, 28 texture parameters based on grey-level co-occurrence matrices (GLCOM), intensity histograms (GLIH), neighborhood difference matrices (GLNDM), and zone size matrices (GLZSM) were evaluated within lesions of diameter of 33, 28, 22, and 17mm. Results: In reference to the isotopic image data, texture features appearing on the rectangular voxel data varied with a range of -34-10% for GLCOM based, -31-39% for GLIH based, -80 -161% for GLNDM based, and −6–45% for GLZSM based while varied with a range of -35-23% for GLCOM based, -27-35% for GLIH based, -65-86% for GLNDM based, and -22 -18% for GLZSM based for the interpolated image data. For the anisotropic data, GLNDM-cplx exhibited the largest extent of variation (161%) while GLZSM-zp showed the least (<1%). As to the interpolated data, GLNDM-busy varied the most (86%) while GLIH-engy varied the least (<1%). Conclusion: Variability of texture appearance on oncologic PET with respect to voxel representation is substantial and feature-dependent. It necessitates consideration of standardized voxel representation for inter

Estimation of Temporal Gait Parameters Using a Wearable Microphone-Sensor-Based System

PubMed Central

Wang, Cheng; Wang, Xiangdong; Long, Zhou; Yuan, Jing; Qian, Yueliang; Li, Jintao

2016-01-01

Most existing wearable gait analysis methods focus on the analysis of data obtained from inertial sensors. This paper proposes a novel, low-cost, wireless and wearable gait analysis system which uses microphone sensors to collect footstep sound signals during walking. This is the first time a microphone sensor is used as a wearable gait analysis device as far as we know. Based on this system, a gait analysis algorithm for estimating the temporal parameters of gait is presented. The algorithm fully uses the fusion of two feet footstep sound signals and includes three stages: footstep detection, heel-strike event and toe-on event detection, and calculation of gait temporal parameters. Experimental results show that with a total of 240 data sequences and 1732 steps collected using three different gait data collection strategies from 15 healthy subjects, the proposed system achieves an average 0.955 F1-measure for footstep detection, an average 94.52% accuracy rate for heel-strike detection and 94.25% accuracy rate for toe-on detection. Using these detection results, nine temporal related gait parameters are calculated and these parameters are consistent with their corresponding normal gait temporal parameters and labeled data calculation results. The results verify the effectiveness of our proposed system and algorithm for temporal gait parameter estimation. PMID:27999321

A Voxel-by-Voxel Comparison of Deformable Vector Fields Obtained by Three Deformable Image Registration Algorithms Applied to 4DCT Lung Studies.

PubMed

Fatyga, Mirek; Dogan, Nesrin; Weiss, Elizabeth; Sleeman, William C; Zhang, Baoshe; Lehman, William J; Williamson, Jeffrey F; Wijesooriya, Krishni; Christensen, Gary E

2015-01-01

Commonly used methods of assessing the accuracy of deformable image registration (DIR) rely on image segmentation or landmark selection. These methods are very labor intensive and thus limited to relatively small number of image pairs. The direct voxel-by-voxel comparison can be automated to examine fluctuations in DIR quality on a long series of image pairs. A voxel-by-voxel comparison of three DIR algorithms applied to lung patients is presented. Registrations are compared by comparing volume histograms formed both with individual DIR maps and with a voxel-by-voxel subtraction of the two maps. When two DIR maps agree one concludes that both maps are interchangeable in treatment planning applications, though one cannot conclude that either one agrees with the ground truth. If two DIR maps significantly disagree one concludes that at least one of the maps deviates from the ground truth. We use the method to compare 3 DIR algorithms applied to peak inhale-peak exhale registrations of 4DFBCT data obtained from 13 patients. All three algorithms appear to be nearly equivalent when compared using DICE similarity coefficients. A comparison based on Jacobian volume histograms shows that all three algorithms measure changes in total volume of the lungs with reasonable accuracy, but show large differences in the variance of Jacobian distribution on contoured structures. Analysis of voxel-by-voxel subtraction of DIR maps shows differences between algorithms that exceed a centimeter for some registrations. Deformation maps produced by DIR algorithms must be treated as mathematical approximations of physical tissue deformation that are not self-consistent and may thus be useful only in applications for which they have been specifically validated. The three algorithms tested in this work perform fairly robustly for the task of contour propagation, but produce potentially unreliable results for the task of DVH accumulation or measurement of local volume change. Performance of

A Pilot Study of Gait Function in Farmworkers in Eastern North Carolina.

PubMed

Nguyen, Ha T; Kritchevsky, Stephen B; Foxworth, Judy L; Quandt, Sara A; Summers, Phillip; Walker, Francis O; Arcury, Thomas A

2015-01-01

Farmworkers endure many job-related hazards, including fall-related work injuries. Gait analysis may be useful in identifying potential fallers. The goal of this pilot study was to explore differences in gait between farmworkers and non-farmworkers. The sample included 16 farmworkers and 24 non-farmworkers. Gait variables were collected using the portable GAITRite system, a 16-foot computerized walkway. Generalized linear regression models were used to examine group differences. All models were adjusted for two established confounders, age and body mass index. There were no significant differences in stride length, step length, double support time, and base of support; but farmworkers had greater irregularity of stride length (P = .01) and step length (P = .08). Farmworkers performed significantly worse on gait velocity (P = .003) and cadence (P < .001) relative to non-farmworkers. We found differences in gait function between farmworkers and non-farmworkers. These findings suggest that measuring gait with a portable walkway system is feasible and informative in farmworkers and may possibly be of use in assessing fall risk.

Good agreement between smart device and inertial sensor-based gait parameters during a 6-min walk.

PubMed

Proessl, F; Swanson, C W; Rudroff, T; Fling, B W; Tracy, B L

2018-05-28

Traditional laboratory-based kinetic and kinematic gait analyses are expensive, time-intensive, and impractical for clinical settings. Inertial sensors have gained popularity in gait analysis research and more recently smart devices have been employed to provide quantification of gait. However, no study to date has investigated the agreement between smart device and inertial sensor-based gait parameters during prolonged walking. Compare spatiotemporal gait metrics measured with a smart device versus previously validated inertial sensors. Twenty neurologically healthy young adults (7 women; age: 25.0 ± 3.7 years; BMI: 23.4 ± 2.9 kg/m 2 ) performed a 6-min walk test (6MWT) wearing inertial sensors and smart devices to record stride duration, stride length, cadence, and gait speed. Pearson correlations were used to assess associations between spatiotemporal measures from the two devices and agreement between the two methods was assessed with Bland-Altman plots and limits of agreement. All spatiotemporal gait metrics (stride duration, cadence, stride length and gait speed) showed strong (r>0.9) associations and good agreement between the two devices. Smart devices are capable of accurately reflecting many of the spatiotemporal gait metrics of inertial sensors. As the smart devices also accurately reflected individual leg output, future studies may apply this analytical strategy to clinical populations, to identify hallmarks of disability status and disease progression in a more ecologically valid environment. Copyright © 2018. Published by Elsevier B.V.

Absorbed fractions in a voxel-based phantom calculated with the MCNP-4B code.

PubMed

Yoriyaz, H; dos Santos, A; Stabin, M G; Cabezas, R

2000-07-01

A new approach for calculating internal dose estimates was developed through the use of a more realistic computational model of the human body. The present technique shows the capability to build a patient-specific phantom with tomography data (a voxel-based phantom) for the simulation of radiation transport and energy deposition using Monte Carlo methods such as in the MCNP-4B code. MCNP-4B absorbed fractions for photons in the mathematical phantom of Snyder et al. agreed well with reference values. Results obtained through radiation transport simulation in the voxel-based phantom, in general, agreed well with reference values. Considerable discrepancies, however, were found in some cases due to two major causes: differences in the organ masses between the phantoms and the occurrence of organ overlap in the voxel-based phantom, which is not considered in the mathematical phantom.

Increased gray matter density in the parietal cortex of mathematicians: a voxel-based morphometry study.

PubMed

Aydin, K; Ucar, A; Oguz, K K; Okur, O O; Agayev, A; Unal, Z; Yilmaz, S; Ozturk, C

2007-01-01

The training to acquire or practicing to perform a skill, which may lead to structural changes in the brain, is called experience-dependent structural plasticity. The main purpose of this cross-sectional study was to investigate the presence of experience-dependent structural plasticity in mathematicians' brains, which may develop after long-term practice of mathematic thinking. Twenty-six volunteer mathematicians, who have been working as academicians, were enrolled in the study. We applied an optimized method of voxel-based morphometry in the mathematicians and the age- and sex-matched control subjects. We assessed the gray and white matter density differences in mathematicians and the control subjects. Moreover, the correlation between the cortical density and the time spent as an academician was investigated. We found that cortical gray matter density in the left inferior frontal and bilateral inferior parietal lobules of the mathematicians were significantly increased compared with the control subjects. Furthermore, increase in gray matter density in the right inferior parietal lobule of the mathematicians was strongly correlated with the time spent as an academician (r = 0.84; P < .01). Left-inferior frontal and bilateral parietal regions are involved in arithmetic processing. Inferior parietal regions are also involved in high-level mathematic thinking, which requires visuospatial imagery, such as mental creation and manipulation of 3D objects. The voxel-based morphometric analysis of mathematicians' brains revealed increased gray matter density in the cortical regions related to mathematic thinking. The correlation between cortical density increase and the time spent as an academician suggests experience-dependent structural plasticity in mathematicians' brains.

Crowd-Sourced Amputee Gait Data: A Feasibility Study Using YouTube Videos of Unilateral Trans-Femoral Gait.

PubMed

Gardiner, James; Gunarathne, Nuwan; Howard, David; Kenney, Laurence

2016-01-01

Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area.

Crowd-Sourced Amputee Gait Data: A Feasibility Study Using YouTube Videos of Unilateral Trans-Femoral Gait

PubMed Central

Gardiner, James; Gunarathne, Nuwan; Howard, David; Kenney, Laurence

2016-01-01

Collecting large datasets of amputee gait data is notoriously difficult. Additionally, collecting data on less prevalent amputations or on gait activities other than level walking and running on hard surfaces is rarely attempted. However, with the wealth of user-generated content on the Internet, the scope for collecting amputee gait data from alternative sources other than traditional gait labs is intriguing. Here we investigate the potential of YouTube videos to provide gait data on amputee walking. We use an example dataset of trans-femoral amputees level walking at self-selected speeds to collect temporal gait parameters and calculate gait asymmetry. We compare our YouTube data with typical literature values, and show that our methodology produces results that are highly comparable to data collected in a traditional manner. The similarity between the results of our novel methodology and literature values lends confidence to our technique. Nevertheless, clear challenges with the collection and interpretation of crowd-sourced gait data remain, including long term access to datasets, and a lack of validity and reliability studies in this area. PMID:27764226

Inter- and intraobserver repeatability of the Salford Gait Tool: an observation-based clinical gait assessment tool.

PubMed

Toro, Brigitte; Nester, Christopher J; Farren, Pauline C

2007-03-01

To evaluate the inter- and intraobserver repeatability of the Salford Gait Tool (SF-GT), a new observation-based gait assessment tool for evaluating sagittal plane cerebral palsy (CP) gait. Masked comparative evaluation. University in the United Kingdom. A convenience sample of 23 pediatric physical therapists with varying degrees of clinical experience recruited from the Greater Manchester area. Participants viewed videotapes of the sagittal plane gait of 13 children and used the SF-GT to analyze their 13 different gait styles on 2 occasions. Eleven children had hemiplegic, diplegic, or quadriplegic CP and 2 were neurologically intact. Inter- and intraobserver repeatability of hip, knee, and ankle joint positions at 6 different phases of the gait cycle. The SF-GT demonstrated good interobserver (77%) and intraobserver (75%) repeatability. We have established that the SF-GT is a repeatable clinical assessment tool with which to guide the diagnosis, treatment planning, and evaluation of interventions by pediatric physical therapists of sagittal plane gait deviations in CP.

Exoskeleton-assisted gait training to improve gait in individuals with spinal cord injury: a pilot randomized study.

PubMed

Chang, Shuo-Hsiu; Afzal, Taimoor; Berliner, Jeffrey; Francisco, Gerard E

2018-01-01

Robotic wearable exoskeletons have been utilized as a gait training device in persons with spinal cord injury. This pilot study investigated the feasibility of offering exoskeleton-assisted gait training (EGT) on gait in individuals with incomplete spinal cord injury (iSCI) in preparation for a phase III RCT. The objective was to assess treatment reliability and potential efficacy of EGT and conventional physical therapy (CPT). Forty-four individuals were screened, and 13 were eligible to participate in the study. Nine participants consented and were randomly assigned to receive either EGT or CPT with focus on gait. Subjects received EGT or CPT, five sessions a week (1 h/session daily) for 3 weeks. American Spinal Injury Association (ASIA) Lower Extremity Motor Score (LEMS), 10-Meter Walk Test (10MWT), 6-Minute Walk Test (6MWT), Timed Up and Go (TUG) test, and gait characteristics including stride and step length, cadence and stance, and swing phase durations were assessed at the pre- and immediate post- training. Mean difference estimates with 95% confidence intervals were used to analyze the differences. After training, improvement was observed in the 6MWT for the EGT group. The CPT group showed significant improvement in the TUG test. Both the EGT and the CPT groups showed significant increase in the right step length. EGT group also showed improvement in the stride length. EGT could be applied to individuals with iSCI to facilitate gait recovery. The subjects were able to tolerate the treatment; however, exoskeleton size range may be a limiting factor in recruiting larger cohort of patients. Future studies with larger sample size are needed to investigate the effectiveness and efficacy of exoskeleton-assisted gait training as single gait training and combined with other gait training strategies. Clinicaltrials.org, NCT03011099, retrospectively registered on January 3, 2017.

Voxel-based morphometric multisite collaborative study on schizophrenia.

PubMed

Segall, Judith M; Turner, Jessica A; van Erp, Theo G M; White, Tonya; Bockholt, H Jeremy; Gollub, Randy L; Ho, Beng C; Magnotta, Vince; Jung, Rex E; McCarley, Robert W; Schulz, S Charles; Lauriello, John; Clark, Vince P; Voyvodic, James T; Diaz, Michele T; Calhoun, Vince D

2009-01-01

Regional gray matter (GM) abnormalities are well known to exist in patients with chronic schizophrenia. Voxel-based morphometry (VBM) has been previously used on structural magnetic resonance images (MRI) data to characterize these abnormalities. Two multisite schizophrenia studies, the Functional Biomedical Informatics Research Network and the Mind Clinical Imaging Consortium, which include 9 data collection sites, are evaluating the efficacy of pooling structural imaging data across imaging centers. Such a pooling of data could yield the increased statistical power needed to elucidate effects that may not be seen with smaller samples. VBM analyses were performed to evaluate the consistency of patient versus control gray matter concentration (GMC) differences across the study sites, as well as the effects of combining multisite data. Integration of data from both studies yielded a large sample of 503 subjects, including 266 controls and 237 patients diagnosed with schizophrenia, schizoaffective or schizophreniform disorder. The data were analyzed using the combined sample, as well as analyzing each of the 2 multisite studies separately. A consistent pattern of reduced relative GMC in schizophrenia patients compared with controls was found across all study sites. Imaging center-specific effects were evaluated using a region of interest analysis. Overall, the findings support the use of VBM in combined multisite studies. This analysis of schizophrenics and controls from around the United States provides continued supporting evidence for GM deficits in the temporal lobes, anterior cingulate, and frontal regions in patients with schizophrenia spectrum disorders.

Brain structural changes and their correlation with vascular disease in type 2 diabetes mellitus patients: a voxel-based morphometric study.

PubMed

Wang, Chunxia; Fu, Kailiang; Liu, Huaijun; Xing, Fei; Zhang, Songyun

2014-08-15

Voxel-based morphometry has been used in the study of alterations in brain structure in type 1 diabetes mellitus patients. These changes are associated with clinical indices. The age at onset, pathogenesis, and treatment of type 1 diabetes mellitus are different from those for type 2 diabetes mellitus. Thus, type 1 and type 2 diabetes mellitus may have different impacts on brain structure. Only a few studies of the alterations in brain structure in type 2 diabetes mellitus patients using voxel-based morphometry have been conducted, with inconsistent results. We detected subtle changes in the brain structure of 23 cases of type 2 diabetes mellitus, and demonstrated that there was no significant difference between the total volume of gray and white matter of the brain of type 2 diabetes mellitus patients and that in controls. Regional atrophy of gray matter mainly occurred in the right temporal and left occipital cortex, while regional atrophy of white matter involved the right temporal lobe and the right cerebellar hemisphere. The ankle-brachial index in patients with type 2 diabetes mellitus strongly correlated with the volume of brain regions in the default mode network. The ankle-brachial index, followed by the level of glycosylated hemoglobin, most strongly correlated with the volume of gray matter in the right temporal lobe. These data suggest that voxel-based morphometry could detect small structural changes in patients with type 2 diabetes mellitus. Early macrovascular atherosclerosis may play a crucial role in subtle brain atrophy in type 2 diabetes mellitus patients, with chronic hyperglycemia playing a lesser role.

Modification of hemiplegic compensatory gait pattern by symmetry-based motion controller of HAL.

PubMed

Kawamoto, Hiroaki; Kadone, Hideki; Sakurai, Takeru; Sankai, Yoshiyuki

2015-01-01

As one of several characteristics of hemiplegic patients after stroke, compensatory gait caused by affected limb is often seen. The purpose of this research is to apply a symmetry-based controller of a wearable type lower limb robot, Hybrid Assistive Limb (HAL) to hemiplegic patients with compensatory gait, and to investigate improvement of gait symmetry. The controller is designed respectively for swing phase and support phase according to characteristics of hemiplegic gait pattern. The controller during swing phase stores the motion of the unaffected limb and then provides motion support on the affected limb during the subsequent swing using the stored pattern to realize symmetric gait based on spontaneous limb swing. Moreover, the controller during support phase provides motion to extend hip and knee joints to support wearer's body. Clinical tests were conducted in order to assess the modification of gait symmetry. Our case study involved participation of one chronic stroke patient who performs abnormally-compensatory gait for both of the affected and unaffected limbs. As a result, the patient's gait symmetry was improved by providing motion support during the swing phase on the affected side and motion constraint during the support phase on the unaffected side. The study showed promising basis for the effectiveness of the controller for the future clinical study.

Different cognitive functions discriminate gait performance in younger and older women: A pilot study.

PubMed

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

2016-10-01

Cognitive dysfunction is associated with slower gait speed in older women, but whether cognitive function affects gait performance earlier in life has yet to be investigated. Thus, the objective of this study was to test the hypothesis that cognitive function will discriminate gait performance in healthy younger women. Fast-pace and dual-task gait speed were measured in 30 young to middle-aged (30-45y) and 26 older (61-80y) women without mild cognitive impairment. Visuoperceptual ability, working memory, executive function, and learning ability were assessed using neuropsychological tests. Within each age group, women were divided by the median into lower and higher cognitive function groups to compare gait performance. Younger women with higher visuoperceptual ability had faster fast-pace (2.25±0.30 vs. 1.98±0.18m/s, p≤0.01) and dual-task gait speed (2.02±0.27 vs. 1.69±0.25m/s, p≤0.01) than women with lower visuoperceptual ability. The difference in dual-task gait speed remained significant (p=0.02) after adjusting for age, years of education, and other covariates. Dividing younger women based on other cognitive domains showed no difference in gait performance. In contrast, working memory and executive function discriminated dual-task gait speed (p<0.05) in older women after adjusting for age and education. To our knowledge, this is the first study to show that poorer cognitive function even at a relatively young age can negatively impact mobility. Different cognitive functions discriminated gait performance based on age, highlighting a possible influence of aging in the relationship between cognitive function and mobility in women. Copyright © 2016 Elsevier B.V. All rights reserved.

GaitaBase: Web-based repository system for gait analysis.

PubMed

Tirosh, Oren; Baker, Richard; McGinley, Jenny

2010-02-01

The need to share gait analysis data to improve clinical decision support has been recognised since the early 1990s. GaitaBase has been established to provide a web-accessible repository system of gait analysis data to improve the sharing of data across local and international clinical and research community. It is used by several clinical and research groups across the world providing cross-group access permissions to retrieve and analyse the data. The system is useful for bench-marking and quality assurance, clinical consultation, and collaborative research. It has the capacity to increase the population sample size and improve the quality of 'normative' gait data. In addition the accumulated stored data may facilitate clinicians in comparing their own gait data with others, and give a valuable insight into how effective specific interventions have been for others. 2009 Elsevier Ltd. All rights reserved.

A voxel-based technique to estimate the volume of trees from terrestrial laser scanner data

NASA Astrophysics Data System (ADS)

Bienert, A.; Hess, C.; Maas, H.-G.; von Oheimb, G.

2014-06-01

The precise determination of the volume of standing trees is very important for ecological and economical considerations in forestry. If terrestrial laser scanner data are available, a simple approach for volume determination is given by allocating points into a voxel structure and subsequently counting the filled voxels. Generally, this method will overestimate the volume. The paper presents an improved algorithm to estimate the wood volume of trees using a voxel-based method which will correct for the overestimation. After voxel space transformation, each voxel which contains points is reduced to the volume of its surrounding bounding box. In a next step, occluded (inner stem) voxels are identified by a neighbourhood analysis sweeping in the X and Y direction of each filled voxel. Finally, the wood volume of the tree is composed by the sum of the bounding box volumes of the outer voxels and the volume of all occluded inner voxels. Scan data sets from several young Norway maple trees (Acer platanoides) were used to analyse the algorithm. Therefore, the scanned trees as well as their representing point clouds were separated in different components (stem, branches) to make a meaningful comparison. Two reference measurements were performed for validation: A direct wood volume measurement by placing the tree components into a water tank, and a frustum calculation of small trunk segments by measuring the radii along the trunk. Overall, the results show slightly underestimated volumes (-0.3% for a probe of 13 trees) with a RMSE of 11.6% for the individual tree volume calculated with the new approach.

WE-D-BRE-06: Quantification of Dose-Response for High Grade Esophagtis Patients Using a Novel Voxel-To-Voxel Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niedzielski, J; Martel, M; Tucker, S

2014-06-15

Purpose: Radiation induces an inflammatory response in the esophagus, discernible on CT studies. This work objectively quantifies the voxel esophageal radiation-response for patients with acute esophagitis. This knowledge is an important first-step towards predicting the effect of complex dose distributions on patient esophagitis symptoms. Methods: A previously validated voxel-based methodology of quantifying radiation esophagitis severity was used to identify the voxel dose-response for 18 NSCLC patients with severe esophagitis (CTCAE grading criteria, grade2 or higher). The response is quantified as percent voxel volume change for a given dose. During treatment (6–8 weeks), patients had weekly 4DCT studies and esophagitis scoring.more » Planning CT esophageal contours were deformed to each weekly CT using a demons DIR algorithm. An algorithm using the Jacobian Map from the DIR of the planning CT to all weekly CTs was used to quantify voxel-volume change, along with corresponding delivered voxel dose, to the planning voxel. Dose for each voxel for each time-point was calculated on each previous weekly CT image, and accumulated using DIR. Thus, for each voxel, the volume-change and delivered dose was calculated for each time-point. The data was binned according to when the volume-change first increased by a threshold volume (10%–100%, in 10% increments), and the average delivered dose calculated for each bin. Results: The average dose resulting in a voxel volume increase of 10–100% was 21.6 to 45.9Gy, respectively. The mean population dose to give a 50% volume increase was 36.3±4.4Gy, (range:29.8 to 43.5Gy). The average week of 50% response was 4.1 (range:4.9 to 2.8 weeks). All 18 patients showed similar dose to first response curves, showing a common trend in the initial inflammatoryresponse. Conclusion: We extracted the dose-response curve of the esophagus on a voxel-to-voxel level. This may be useful for estimating the esophagus response (and patient

Creativity and borderline personality disorder: evidence from a voxel-based morphometry study.

PubMed

Leutgeb, Verena; Ille, Rottraut; Wabnegger, Albert; Schienle, Anne; Schöggl, Helmut; Weber, Bernhard; Papousek, Ilona; Weiss, Elisabeth M; Fink, Andreas

2016-05-01

Throughout the history, various examples of eminent creative people suffering from mental disorders along with some empirical research reports strengthened the idea of a potential link between creativity and psychopathology. This study investigated different facets of psychometrically determined creativity in 20 females diagnosed with borderline personality disorder (BPD) relative to 19 healthy female controls. In addition, group differences in grey matter (GM) were examined. Behavioural findings revealed no significant differences between the BPD group and healthy controls with respect to verbal and figural-graphic creative task performance and creativity-related personality characteristics. Whole-brain voxel-based morphometry analyses revealed a distinct pattern of GM reductions in the BPD group (relative to controls) in a network of brain regions closely associated with various cognitive and emotional functions (including the bilateral orbital inferior frontal gyri and the left superior temporal gyrus), partly overlapping with creativity-related brain regions. Correlation analyses moreover revealed that in the BPD group GM reductions in the orbital parts of the inferior and middle frontal gyri were associated with lower levels of creativity. This study provides no indications in favour of the putative link between creativity and psychopathology, as sometimes reported in the literature.

Brain correlates of pro-social personality traits: a voxel-based morphometry study.

PubMed

Coutinho, Joana F; Sampaio, Adriana; Ferreira, Miguel; Soares, José M; Gonçalves, Oscar F

2013-09-01

Of the five personality dimensions described by the Big Five Personality Model (Costa and McCrae 1992), Extraversion and Agreeableness are the traits most commonly associated with a pro-social orientation. In this study we tested whether a pro-social orientation, as expressed in terms of Extraversion and Agreeableness, is associated with a specific grey matter phenotype. Fifty-two healthy participants underwent magnetic resonance imaging (MRI) and completed the NEO-Five Factor Inventory (NEO-FFI), a self-report measure of the Big Five personality traits. Voxel-based morphometry (VBM) was used to investigate the correlation between brain structure and the personality traits of Agreeableness and Extraversion. We found that Extraversion was negatively correlated with grey matter density in the middle frontal and orbitofrontal gyri while Agreeableness was negatively correlated with grey matter density in the inferior parietal, middle occipital and posterior cingulate gyri. No positive correlations were found. These results suggest that pro-social personality traits seem to be associated with decreases in grey matter density in more frontal regions for Extraversion, and more posterior regions for Agreeableness.

Effect of normal-walking-pattern-based functional electrical stimulation on gait of the lower extremity in subjects with ischemic stroke: A self controlled study.

PubMed

Xu, Benlei; Yan, Tiebin; Yang, Yuanle; Ou, Ruiqing; Huang, Shuping

2016-01-01

Functional electrical stimulation is a widely used technique for rehabilitation. To assess the efficacy of walking-pattern-based four-channel functional electric stimulation and its influence on the gait features of stroke patients with hemiplegia. A total of 21 stroke patients with hemiplegia were enrolled into the study. The walking gaits of patients were investigated before, during and after walking-pattern-based FES treatment using the gait analysis system. The changes of gait indexes were comparatively analyzed. After walking-pattern-based FES therapy, the pace, stride rate, gait cycle, and step length of stroke patients with hemiplegia were 50.19 ± 14.45 cm/s, 36.85 ± 5.85 time/min, 1.6643 ± 0.2626 sec, 80.3333 ± 15.1438 cm, respectively. The motion range of hip and knee joint were 47.5238 ± 10.7453, 56.7619 ± 14.5255, respectively. We found these indexes were significantly improved compared with those before FES treatment (P <  0.05). The single swing rate (injured extremity/uninjured extremity) after FES treatment was 1.5589 ± 0.4550. The statistical results showed that the gait cycle, pace, stride rat, and single swing rate (injured extremity/uninjured extremity) were significantly improved after FES treatment (P <  0.05). Our results demonstrate that walking-paradigm based FES we developed is effective for treating stroke patients during rehabilitation.

A Fully GPU-Based Ray-Driven Backprojector via a Ray-Culling Scheme with Voxel-Level Parallelization for Cone-Beam CT Reconstruction.

PubMed

Park, Hyeong-Gyu; Shin, Yeong-Gil; Lee, Ho

2015-12-01

A ray-driven backprojector is based on ray-tracing, which computes the length of the intersection between the ray paths and each voxel to be reconstructed. To reduce the computational burden caused by these exhaustive intersection tests, we propose a fully graphics processing unit (GPU)-based ray-driven backprojector in conjunction with a ray-culling scheme that enables straightforward parallelization without compromising the high computing performance of a GPU. The purpose of the ray-culling scheme is to reduce the number of ray-voxel intersection tests by excluding rays irrelevant to a specific voxel computation. This rejection step is based on an axis-aligned bounding box (AABB) enclosing a region of voxel projection, where eight vertices of each voxel are projected onto the detector plane. The range of the rectangular-shaped AABB is determined by min/max operations on the coordinates in the region. Using the indices of pixels inside the AABB, the rays passing through the voxel can be identified and the voxel is weighted as the length of intersection between the voxel and the ray. This procedure makes it possible to reflect voxel-level parallelization, allowing an independent calculation at each voxel, which is feasible for a GPU implementation. To eliminate redundant calculations during ray-culling, a shared-memory optimization is applied to exploit the GPU memory hierarchy. In experimental results using real measurement data with phantoms, the proposed GPU-based ray-culling scheme reconstructed a volume of resolution 28032803176 in 77 seconds from 680 projections of resolution 10243768 , which is 26 times and 7.5 times faster than standard CPU-based and GPU-based ray-driven backprojectors, respectively. Qualitative and quantitative analyses showed that the ray-driven backprojector provides high-quality reconstruction images when compared with those generated by the Feldkamp-Davis-Kress algorithm using a pixel-driven backprojector, with an average of 2.5 times

A Mobile Kalman-Filter Based Solution for the Real-Time Estimation of Spatio-Temporal Gait Parameters.

PubMed

Ferrari, Alberto; Ginis, Pieter; Hardegger, Michael; Casamassima, Filippo; Rocchi, Laura; Chiari, Lorenzo

2016-07-01

Gait impairments are among the most disabling symptoms in several musculoskeletal and neurological conditions, severely limiting personal autonomy. Wearable gait sensors have been attracting attention as diagnostic tool for gait and are emerging as promising tool for tutoring and guiding gait execution. If their popularity is continuously growing, still there is room for improvement, especially towards more accurate solutions for spatio-temporal gait parameters estimation. We present an implementation of a zero-velocity-update gait analysis system based on a Kalman filter and off-the-shelf shoe-worn inertial sensors. The algorithms for gait events and step length estimation were specifically designed to comply with pathological gait patterns. More so, an Android app was deployed to support fully wearable and stand-alone real-time gait analysis. Twelve healthy subjects were enrolled to preliminarily tune the algorithms; afterwards sixteen persons with Parkinson's disease were enrolled for a validation study. Over the 1314 strides collected on patients at three different speeds, the total root mean square difference on step length estimation between this system and a gold standard was 2.9%. This shows that the proposed method allows for an accurate gait analysis and paves the way to a new generation of mobile devices usable anywhere for monitoring and intervention.

Towards autonomous locomotion: CPG-based control of smooth 3D slithering gait transition of a snake-like robot.

PubMed

Bing, Zhenshan; Cheng, Long; Chen, Guang; Röhrbein, Florian; Huang, Kai; Knoll, Alois

2017-04-04

Snake-like robots with 3D locomotion ability have significant advantages of adaptive travelling in diverse complex terrain over traditional legged or wheeled mobile robots. Despite numerous developed gaits, these snake-like robots suffer from unsmooth gait transitions by changing the locomotion speed, direction, and body shape, which would potentially cause undesired movement and abnormal torque. Hence, there exists a knowledge gap for snake-like robots to achieve autonomous locomotion. To address this problem, this paper presents the smooth slithering gait transition control based on a lightweight central pattern generator (CPG) model for snake-like robots. First, based on the convergence behavior of the gradient system, a lightweight CPG model with fast computing time was designed and compared with other widely adopted CPG models. Then, by reshaping the body into a more stable geometry, the slithering gait was modified, and studied based on the proposed CPG model, including the gait transition of locomotion speed, moving direction, and body shape. In contrast to sinusoid-based method, extensive simulations and prototype experiments finally demonstrated that smooth slithering gait transition can be effectively achieved using the proposed CPG-based control method without generating undesired locomotion and abnormal torque.

Voxel-Based 3-D Tree Modeling from Lidar Images for Extracting Tree Structual Information

NASA Astrophysics Data System (ADS)

Hosoi, F.

2014-12-01

Recently, lidar (light detection and ranging) has been used to extracting tree structural information. Portable scanning lidar systems can capture the complex shape of individual trees as a 3-D point-cloud image. 3-D tree models reproduced from the lidar-derived 3-D image can be used to estimate tree structural parameters. We have proposed the voxel-based 3-D modeling for extracting tree structural parameters. One of the tree parameters derived from the voxel modeling is leaf area density (LAD). We refer to the method as the voxel-based canopy profiling (VCP) method. In this method, several measurement points surrounding the canopy and optimally inclined laser beams are adopted for full laser beam illumination of whole canopy up to the internal. From obtained lidar image, the 3-D information is reproduced as the voxel attributes in the 3-D voxel array. Based on the voxel attributes, contact frequency of laser beams on leaves is computed and LAD in each horizontal layer is obtained. This method offered accurate LAD estimation for individual trees and woody canopy trees. For more accurate LAD estimation, the voxel model was constructed by combining airborne and portable ground-based lidar data. The profiles obtained by the two types of lidar complemented each other, thus eliminating blind regions and yielding more accurate LAD profiles than could be obtained by using each type of lidar alone. Based on the estimation results, we proposed an index named laser beam coverage index, Ω, which relates to the lidar's laser beam settings and a laser beam attenuation factor. It was shown that this index can be used for adjusting measurement set-up of lidar systems and also used for explaining the LAD estimation error using different types of lidar systems. Moreover, we proposed a method to estimate woody material volume as another application of the voxel tree modeling. In this method, voxel solid model of a target tree was produced from the lidar image, which is composed of

Effect of Experimental Thyrotoxicosis on Brain Gray Matter: A Voxel-Based Morphometry Study.

PubMed

Göbel, Anna; Heldmann, Marcus; Göttlich, Martin; Dirk, Anna-Luise; Brabant, Georg; Münte, Thomas F

2015-09-01

Hyper-as well hypothyroidism have an effect on behavior and brain function. Moreover, during development thyroid hormones influence brain structure. This study aimed to demonstrate an effect of experimentally induced hyperthyroidism on brain gray matter in healthy adult humans. High-resolution 3D T1-weighted images were acquired in 29 healthy young subjects prior to as well as after receiving 250 µg of T4 per day for 8 weeks. Voxel-based morphometry analysis was performed using Statistical Parametric Mapping 8 (SPM8). Laboratory testing confirmed the induction of hyperthyroidism. In the hyperthyroid condition, gray matter volumes were increased in the right posterior cerebellum (lobule VI) and decreased in the bilateral visual cortex and anterior cerebellum (lobules I-IV) compared to the euthyroid condition. Our study provides evidence that short periods of hyperthyroidism induce distinct alterations in brain structures of cerebellar regions that have been associated with sensorimotor functions as well as working memory in the literature.

Guidelines for Assessment of Gait and Reference Values for Spatiotemporal Gait Parameters in Older Adults: The Biomathics and Canadian Gait Consortiums Initiative

PubMed Central

Beauchet, Olivier; Allali, Gilles; Sekhon, Harmehr; Verghese, Joe; Guilain, Sylvie; Steinmetz, Jean-Paul; Kressig, Reto W.; Barden, John M.; Szturm, Tony; Launay, Cyrille P.; Grenier, Sébastien; Bherer, Louis; Liu-Ambrose, Teresa; Chester, Vicky L.; Callisaya, Michele L.; Srikanth, Velandai; Léonard, Guillaume; De Cock, Anne-Marie; Sawa, Ryuichi; Duque, Gustavo; Camicioli, Richard; Helbostad, Jorunn L.

2017-01-01

Background: Gait disorders, a highly prevalent condition in older adults, are associated with several adverse health consequences. Gait analysis allows qualitative and quantitative assessments of gait that improves the understanding of mechanisms of gait disorders and the choice of interventions. This manuscript aims (1) to give consensus guidance for clinical and spatiotemporal gait analysis based on the recorded footfalls in older adults aged 65 years and over, and (2) to provide reference values for spatiotemporal gait parameters based on the recorded footfalls in healthy older adults free of cognitive impairment and multi-morbidities. Methods: International experts working in a network of two different consortiums (i.e., Biomathics and Canadian Gait Consortium) participated in this initiative. First, they identified items of standardized information following the usual procedure of formulation of consensus findings. Second, they merged databases including spatiotemporal gait assessments with GAITRite® system and clinical information from the “Gait, cOgnitiOn & Decline” (GOOD) initiative and the Generation 100 (Gen 100) study. Only healthy—free of cognitive impairment and multi-morbidities (i.e., ≤ 3 therapeutics taken daily)—participants aged 65 and older were selected. Age, sex, body mass index, mean values, and coefficients of variation (CoV) of gait parameters were used for the analyses. Results: Standardized systematic assessment of three categories of items, which were demographics and clinical information, and gait characteristics (clinical and spatiotemporal gait analysis based on the recorded footfalls), were selected for the proposed guidelines. Two complementary sets of items were distinguished: a minimal data set and a full data set. In addition, a total of 954 participants (mean age 72.8 ± 4.8 years, 45.8% women) were recruited to establish the reference values. Performance of spatiotemporal gait parameters based on the recorded

Structural Differences in Gray Matter between Glider Pilots and Non-Pilots. A Voxel-Based Morphometry Study

PubMed Central

Ahamed, Tosif; Kawanabe, Motoaki; Ishii, Shin; Callan, Daniel E.

2014-01-01

Glider flying is a unique skill that requires pilots to control an aircraft at high speeds in three dimensions and amidst frequent full-body rotations. In the present study, we investigated the neural correlates of flying a glider using voxel-based morphometry. The comparison between gray matter densities of 15 glider pilots and a control group of 15 non-pilots exhibited significant gray matter density increases in left ventral premotor cortex, anterior cingulate cortex, and the supplementary eye field. We posit that the identified regions might be associated with cognitive and motor processes related to flying, such as joystick control, visuo-vestibular interaction, and oculomotor control. PMID:25506339

Structural Differences in Gray Matter between Glider Pilots and Non-Pilots. A Voxel-Based Morphometry Study.

PubMed

Ahamed, Tosif; Kawanabe, Motoaki; Ishii, Shin; Callan, Daniel E

2014-01-01

Glider flying is a unique skill that requires pilots to control an aircraft at high speeds in three dimensions and amidst frequent full-body rotations. In the present study, we investigated the neural correlates of flying a glider using voxel-based morphometry. The comparison between gray matter densities of 15 glider pilots and a control group of 15 non-pilots exhibited significant gray matter density increases in left ventral premotor cortex, anterior cingulate cortex, and the supplementary eye field. We posit that the identified regions might be associated with cognitive and motor processes related to flying, such as joystick control, visuo-vestibular interaction, and oculomotor control.

Automated health alerts from Kinect-based in-home gait measurements.

PubMed

Stone, Erik E; Skubic, Marjorie; Back, Jessica

2014-01-01

A method for automatically generating alerts to clinicians in response to changes in in-home gait parameters is investigated. Kinect-based gait measurement systems were installed in apartments in a senior living facility. The systems continuously monitored the walking speed, stride time, and stride length of apartment residents. A framework for modeling uncertainty in the residents' gait parameter estimates, which is critical for robust change detection, is developed; along with an algorithm for detecting changes that may be clinically relevant. Three retrospective case studies, of individuals who had their gait monitored for periods ranging from 12 to 29 months, are presented to illustrate use of the alert method. Evidence suggests that clinicians could be alerted to health changes at an early stage, while they are still small and interventions may be most successful. Additional potential uses are also discussed.

The neural substrates of procrastination: A voxel-based morphometry study.

PubMed

Hu, Yue; Liu, Peiwei; Guo, Yiqun; Feng, Tingyong

2018-03-01

Procrastination is a pervasive phenomenon across different cultures and brings about lots of serious consequences, including performance, subjective well-being, and even public policy. However, little is known about the neural substrates of procrastination. In order to shed light upon this question, we investigated the neuroanatomical substrates of procrastination across two independent samples using voxel-based morphometry (VBM) method. The whole-brain analysis showed procrastination was positively correlated with the graymatter (GM) volume of clusters in the parahippocampal gyrus (PHG) and the orbital frontal cortex (OFC), while negatively correlated with the GM volume of clusters in the inferior frontal gyrus (IFG) and the middle frontal gyrus (MFG) in sample one (151 participants). We further conducted a verification procedure on another sample (108 participants) using region-of-interest analysis to examine the reliability of these results. Results showed procrastination can be predicted by the GM volume of the OFC and the MFG. The present findings suggest that the MFG and OFC, which are the key regions of self-control and emotion regulation, may play an important role in procrastination. Copyright © 2018 Elsevier Inc. All rights reserved.

A study of the passive gait of a compass-like biped robot: Symmetry and chaos

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goswami, A.; Espiau, B.; Thuilot, B.

1998-12-01

The focus of this work is a systematic study of the passive gait of a compass-like planar, biped robot on inclined slopes. The robot is kinematically equivalent to a double pendulum, possessing two kneeless legs with point masses and a third point mass at the hip joint. Three parameters, namely, the ground-slope angle and the normalized mass and length of the robot describe its gait. The authors show that in response to a continuous change in any one of its parameters, the symmetric and steady stable gait of the unpowered robot gradually evolves through a regime of bifurcations characterized bymore » progressively complicated asymmetric gaits, eventually arriving at an apparently chaotic gait where not two steps are identical. The robot can maintain this gait indefinitely. A necessary (but not sufficient) condition for the stability of such gaits is the contraction of the phase-fluid volume. For this frictionless robot, the volume contraction, which the authors compute, is caused by the dissipative effects of the ground-impact model. In the chaotic regime, the fractal dimension of the robot`s strange attractor (2.07) compared to its state-space dimension (4) also reveals strong contraction. The authors present a novel graphical technique based on the first return map that compactly captures the entire evolution of the gait, from symmetry to chaos. Additional passive dissipative elements in the robot joint results in a significant improvement in the stability and the versatility of the gait, and provide a rich repertoire for simple controls laws.« less

Neuroanatomical correlates of time perspective: A voxel-based morphometry study.

PubMed

Chen, Zhiyi; Guo, Yiqun; Feng, Tingyong

2018-02-26

Previous studies indicated that time perspective can affect many behaviors, such as decisions, risk taking, substance abuse and health behaviors. However, very little is known about the neural substrates of time perspective (TP). To address this question, we characterized different dimensions of TP (including the Past, Present, and Future TP) using standardized Zimbardo Time Perspective Inventory (ZTPI), and quantified the gray matter volume using voxel-based morphometry (VBM) method across two independent samples. Our whole-brain analysis (sample 1, N=150) revealed Past-Negative TP was positively correlated with the GMV of a cluster in LPFC whereas Past-Positive was negatively correlated with the GMV in OFC, and Future TP was negatively correlated with GMV in mPFC. Moreover, two present scales (Present-Hedonistic and Present-Fatalistic TPs) were positively correlated with the GMV of regions in MTG and precuneus, respectively. We further examined the reliability of these correlations between multidimensional TPs and neuroanatomical structures in another independent sample (sample 2, N=58). Results verified our findings that GMV in LPFC could predict Past-Negative TP while GMV in OFC could predict Past-Positive TP, and the GMV in MTG could predict Present-Hedonistic while the GMV in presuneus could predict Present-Fatalistic, as well as the GMV in mPFC could predict Future TP. Thus, our findings suggest that the existence of selective neural basis underlying TPs, and further provide the stable biomarkers for multidimensional TPs. Copyright © 2017 Elsevier B.V. All rights reserved.

Voxel-Based Approach for Estimating Urban Tree Volume from Terrestrial Laser Scanning Data

NASA Astrophysics Data System (ADS)

Vonderach, C.; Voegtle, T.; Adler, P.

2012-07-01

The importance of single trees and the determination of related parameters has been recognized in recent years, e.g. for forest inventories or management. For urban areas an increasing interest in the data acquisition of trees can be observed concerning aspects like urban climate, CO2 balance, and environmental protection. Urban trees differ significantly from natural systems with regard to the site conditions (e.g. technogenic soils, contaminants, lower groundwater level, regular disturbance), climate (increased temperature, reduced humidity) and species composition and arrangement (habitus and health status) and therefore allometric relations cannot be transferred from natural sites to urban areas. To overcome this problem an extended approach was developed for a fast and non-destructive extraction of branch volume, DBH (diameter at breast height) and height of single trees from point clouds of terrestrial laser scanning (TLS). For data acquisition, the trees were scanned with highest scan resolution from several (up to five) positions located around the tree. The resulting point clouds (20 to 60 million points) are analysed with an algorithm based on voxel (volume elements) structure, leading to an appropriate data reduction. In a first step, two kinds of noise reduction are carried out: the elimination of isolated voxels as well as voxels with marginal point density. To obtain correct volume estimates, the voxels inside the stem and branches (interior voxels) where voxels contain no laser points must be regarded. For this filling process, an easy and robust approach was developed based on a layer-wise (horizontal layers of the voxel structure) intersection of four orthogonal viewing directions. However, this procedure also generates several erroneous "phantom" voxels, which have to be eliminated. For this purpose the previous approach was extended by a special region growing algorithm. In a final step the volume is determined layer-wise based on the extracted

Diffusion tensor imaging and voxel based morphometry study in amyotrophic lateral sclerosis: relationships with motor disability

PubMed Central

Thivard, Lionel; Pradat, Pierre‐François; Lehéricy, Stéphane; Lacomblez, Lucette; Dormont, Didier; Chiras, Jacques; Benali, Habib; Meininger, Vincent

2007-01-01

The aim of this study was to investigate the extent of cortical and subcortical lesions in amyotrophic lateral sclerosis (ALS) using, in combination, voxel based diffusion tensor imaging (DTI) and voxel based morphometry (VBM). We included 15 patients with definite or probable ALS and 25 healthy volunteers. Patients were assessed using the revised ALS Functional Rating Scale (ALSFRS‐R). In patients, reduced fractional anisotropy was found in bilateral corticospinal tracts, the left insula/ventrolateral premotor cortex, the right parietal cortex and the thalamus, which correlated with the ALSFRS‐R. Increased mean diffusivity (MD) was found bilaterally in the motor cortex, the ventrolateral premotor cortex/insula, the hippocampal formations and the right superior temporal gyrus, which did not correlate with the ALSFRS‐R. VBM analysis showed no changes in white matter but widespread volume decreases in grey matter in several regions exhibiting MD abnormalities. In ALS patients, our results show that subcortical lesions extend beyond the corticospinal tract and are clinically relevant. PMID:17635981

Diffusion tensor imaging and voxel based morphometry study in amyotrophic lateral sclerosis: relationships with motor disability.

PubMed

Thivard, Lionel; Pradat, Pierre-François; Lehéricy, Stéphane; Lacomblez, Lucette; Dormont, Didier; Chiras, Jacques; Benali, Habib; Meininger, Vincent

2007-08-01

The aim of this study was to investigate the extent of cortical and subcortical lesions in amyotrophic lateral sclerosis (ALS) using, in combination, voxel based diffusion tensor imaging (DTI) and voxel based morphometry (VBM). We included 15 patients with definite or probable ALS and 25 healthy volunteers. Patients were assessed using the revised ALS Functional Rating Scale (ALSFRS-R). In patients, reduced fractional anisotropy was found in bilateral corticospinal tracts, the left insula/ventrolateral premotor cortex, the right parietal cortex and the thalamus, which correlated with the ALSFRS-R. Increased mean diffusivity (MD) was found bilaterally in the motor cortex, the ventrolateral premotor cortex/insula, the hippocampal formations and the right superior temporal gyrus, which did not correlate with the ALSFRS-R. VBM analysis showed no changes in white matter but widespread volume decreases in grey matter in several regions exhibiting MD abnormalities. In ALS patients, our results show that subcortical lesions extend beyond the corticospinal tract and are clinically relevant.

A Study on Fitts' Law Based Gait Symmetric Evaluation and It's Clinic Application.

PubMed

Rencheng, Wang; Meiqin, Zhang; Xiaonan, Deng; Dewen, Jin; Maobin, Wang; Guangqing, Li

2005-01-01

Symmetry, one of the prominent characters of normal human gait, could be destroyed by some special or abnormal factors such as barrier spanning, walking impediment, etc. Therefore, it becomes an important factor used to evaluate qualities and functions of walking. In this paper, the fitts' law based symmetry index calculation is introduced and its application in clinic test is also reported. The results show that the fitts' law based index is effective in clinic evaluation.

An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles

PubMed Central

González, Iván; Fontecha, Jesús; Hervás, Ramón; Bravo, José

2015-01-01

A new gait phase detection system for continuous monitoring based on wireless sensorized insoles is presented. The system can be used in gait analysis mobile applications, and it is designed for real-time demarcation of gait phases. The system employs pressure sensors to assess the force exerted by each foot during walking. A fuzzy rule-based inference algorithm is implemented on a smartphone and used to detect each of the gait phases based on the sensor signals. Additionally, to provide a solution that is insensitive to perturbations caused by non-walking activities, a probabilistic classifier is employed to discriminate walking forward from other low-level activities, such as turning, walking backwards, lateral walking, etc. The combination of these two algorithms constitutes the first approach towards a continuous gait assessment system, by means of the avoidance of non-walking influences. PMID:26184199

An Ambulatory System for Gait Monitoring Based on Wireless Sensorized Insoles.

PubMed

González, Iván; Fontecha, Jesús; Hervás, Ramón; Bravo, José

2015-07-09

A new gait phase detection system for continuous monitoring based on wireless sensorized insoles is presented. The system can be used in gait analysis mobile applications, and it is designed for real-time demarcation of gait phases. The system employs pressure sensors to assess the force exerted by each foot during walking. A fuzzy rule-based inference algorithm is implemented on a smartphone and used to detect each of the gait phases based on the sensor signals. Additionally, to provide a solution that is insensitive to perturbations caused by non-walking activities, a probabilistic classifier is employed to discriminate walking forward from other low-level activities, such as turning, walking backwards, lateral walking, etc. The combination of these two algorithms constitutes the first approach towards a continuous gait assessment system, by means of the avoidance of non-walking influences.

Gait Phase Estimation Based on Noncontact Capacitive Sensing and Adaptive Oscillators.

PubMed

Zheng, Enhao; Manca, Silvia; Yan, Tingfang; Parri, Andrea; Vitiello, Nicola; Wang, Qining

2017-10-01

This paper presents a novel strategy aiming to acquire an accurate and walking-speed-adaptive estimation of the gait phase through noncontact capacitive sensing and adaptive oscillators (AOs). The capacitive sensing system is designed with two sensing cuffs that can measure the leg muscle shape changes during walking. The system can be dressed above the clothes and free human skin from contacting to electrodes. In order to track the capacitance signals, the gait phase estimator is designed based on the AO dynamic system due to its ability of synchronizing with quasi-periodic signals. After the implementation of the whole system, we first evaluated the offline estimation performance by experiments with 12 healthy subjects walking on a treadmill with changing speeds. The strategy achieved an accurate and consistent gait phase estimation with only one channel of capacitance signal. The average root-mean-square errors in one stride were 0.19 rad (3.0% of one gait cycle) for constant walking speeds and 0.31 rad (4.9% of one gait cycle) for speed transitions even after the subjects rewore the sensing cuffs. We then validated our strategy in a real-time gait phase estimation task with three subjects walking with changing speeds. Our study indicates that the strategy based on capacitive sensing and AOs is a promising alternative for the control of exoskeleton/orthosis.

Does a single gait training session performed either overground or on a treadmill induce specific short-term effects on gait parameters in patients with hemiparesis? A randomized controlled study.

PubMed

Bonnyaud, Céline; Pradon, Didier; Zory, Raphael; Bensmail, Djamel; Vuillerme, Nicolas; Roche, Nicolas

2013-01-01

Gait training for patients with hemiparesis is carried out independently overground or on a treadmill. Several studies have shown differences in hemiparetic gait parameters during overground versus treadmill walking. However, few studies have compared the effects of these 2 gait training conditions on gait parameters, and no study has compared the short-term effects of these techniques on all biomechanical gait parameters. To determine whether a gait training session performed overground or on a treadmill induces specific short-term effects on biomechanical gait parameters in patients with hemiparesis. Twenty-six subjects with hemiparesis were randomly assigned to a single session of either overground or treadmill gait training. The short-term effects on spatiotemporal, kinematic, and kinetic gait parameters were assessed using gait analysis before and immediately after the training and after a 20-minute rest. Speed, cadence, percentage of single support phase, peak knee extension, peak propulsion, and braking on the paretic side were significantly increased after the gait training session. However, there were no specific changes dependent on the type of gait training performed (overground or on a treadmill). A gait training session performed by subjects with hemiparesis overground or on a treadmill did not induce specific short-term effects on biomechanical gait parameters. The increase in gait velocity that followed a gait training session seemed to reflect specific modifications of the paretic lower limb and adaptation of the nonparetic lower limb.

Fine-resolution voxel S values for constructing absorbed dose distributions at variable voxel size.

PubMed

Dieudonné, Arnaud; Hobbs, Robert F; Bolch, Wesley E; Sgouros, George; Gardin, Isabelle

2010-10-01

This article presents a revised voxel S values (VSVs) approach for dosimetry in targeted radiotherapy, allowing dose calculation for any voxel size and shape of a given SPECT or PET dataset. This approach represents an update to the methodology presented in MIRD pamphlet no. 17. VSVs were generated in soft tissue with a fine spatial sampling using the Monte Carlo (MC) code MCNPX for particle emissions of 9 radionuclides: (18)F, (90)Y, (99m)Tc, (111)In, (123)I, (131)I, (177)Lu, (186)Re, and (201)Tl. A specific resampling algorithm was developed to compute VSVs for desired voxel dimensions. The dose calculation was performed by convolution via a fast Hartley transform. The fine VSVs were calculated for cubic voxels of 0.5 mm for electrons and 1.0 mm for photons. Validation studies were done for (90)Y and (131)I VSV sets by comparing the revised VSV approach to direct MC simulations. The first comparison included 20 spheres with different voxel sizes (3.8-7.7 mm) and radii (4-64 voxels) and the second comparison a hepatic tumor with cubic voxels of 3.8 mm. MC simulations were done with MCNPX for both. The third comparison was performed on 2 clinical patients with the 3D-RD (3-Dimensional Radiobiologic Dosimetry) software using the EGSnrc (Electron Gamma Shower National Research Council Canada)-based MC implementation, assuming a homogeneous tissue-density distribution. For the sphere model study, the mean relative difference in the average absorbed dose was 0.20% ± 0.41% for (90)Y and -0.36% ± 0.51% for (131)I (n = 20). For the hepatic tumor, the difference in the average absorbed dose to tumor was 0.33% for (90)Y and -0.61% for (131)I and the difference in average absorbed dose to the liver was 0.25% for (90)Y and -1.35% for (131)I. The comparison with the 3D-RD software showed an average voxel-to-voxel dose ratio between 0.991 and 0.996. The calculation time was below 10 s with the VSV approach and 50 and 15 h with 3D-RD for the 2 clinical patients. This new VSV

Measuring Gait Quality in Parkinson’s Disease through Real-Time Gait Phase Recognition

PubMed Central

Mileti, Ilaria; Germanotta, Marco; Di Sipio, Enrica; Imbimbo, Isabella; Pacilli, Alessandra; Erra, Carmen; Petracca, Martina; Del Prete, Zaccaria; Bentivoglio, Anna Rita; Padua, Luca

2018-01-01

Monitoring gait quality in daily activities through wearable sensors has the potential to improve medical assessment in Parkinson’s Disease (PD). In this study, four gait partitioning methods, two based on thresholds and two based on a machine learning approach, considering the four-phase model, were compared. The methods were tested on 26 PD patients, both in OFF and ON levodopa conditions, and 11 healthy subjects, during walking tasks. All subjects were equipped with inertial sensors placed on feet. Force resistive sensors were used to assess reference time sequence of gait phases. Goodness Index (G) was evaluated to assess accuracy in gait phases estimation. A novel synthetic index called Gait Phase Quality Index (GPQI) was proposed for gait quality assessment. Results revealed optimum performance (G < 0.25) for three tested methods and good performance (0.25 < G < 0.70) for one threshold method. The GPQI resulted significantly higher in PD patients than in healthy subjects, showing a moderate correlation with clinical scales score. Furthermore, in patients with severe gait impairment, GPQI was found higher in OFF than in ON state. Our results unveil the possibility of monitoring gait quality in PD through real-time gait partitioning based on wearable sensors. PMID:29558410

A comparative study of the effects of trunk exercise program in aquatic and land-based therapy on gait in hemiplegic stroke patients.

PubMed

Park, Byoung-Sun; Noh, Ji-Woong; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Park, Jaehong; Kim, Junghwan

2016-06-01

[Purpose] The purpose of this study was to compare the effects of aquatic and land-based trunk exercise program on gait in stroke patients. [Subjects and Methods] The subjects were 28 hemiplegic stroke patients (20 males, 8 females). The subjects performed a trunk exercise program for a total of four weeks. [Results] Walking speed and cycle, stance phase and stride length of the affected side, and the symmetry index of the stance phase significantly improved after the aquatic and land-based trunk exercise program. [Conclusion] These results suggest that the aquatic and land-based trunk exercise program may help improve gait performance ability after stroke.

A comparative study of the effects of trunk exercise program in aquatic and land-based therapy on gait in hemiplegic stroke patients

PubMed Central

Park, Byoung-Sun; Noh, Ji-Woong; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Park, Jaehong; Kim, Junghwan

2016-01-01

[Purpose] The purpose of this study was to compare the effects of aquatic and land-based trunk exercise program on gait in stroke patients. [Subjects and Methods] The subjects were 28 hemiplegic stroke patients (20 males, 8 females). The subjects performed a trunk exercise program for a total of four weeks. [Results] Walking speed and cycle, stance phase and stride length of the affected side, and the symmetry index of the stance phase significantly improved after the aquatic and land-based trunk exercise program. [Conclusion] These results suggest that the aquatic and land-based trunk exercise program may help improve gait performance ability after stroke. PMID:27390444

Neurostructural correlates of two subtypes of specific phobia: a voxel-based morphometry study.

PubMed

Hilbert, Kevin; Evens, Ricarda; Maslowski, Nina Isabel; Wittchen, Hans-Ulrich; Lueken, Ulrike

2015-02-28

The animal and blood-injection-injury (BII) subtypes of specific phobia are both characterized by subjective fear but distinct autonomic reactions to threat. Previous functional neuroimaging studies have related these characteristic responses to shared and non-shared neural underpinnings. However, no comparative structural data are available. This study aims to fill this gap by comparing the two subtypes and also comparing them with a non-phobic control group. Gray and white matter data of 33 snake phobia subjects (SP), 26 dental phobia subjects (DP), and 37 healthy control (HC) subjects were analyzed with voxel-based morphometry. Especially DP differed from HC and SP by showing significantly increased grey matter volumes in widespread areas including the right subgenual anterior cingulate gyrus, left insula, left orbitofrontal and left prefrontal (PFC) cortices. In addition, white matter volume was significantly increased in the left PFC in DP compared with SP. These results are in line with functional changes observed in dental phobia and point toward those brain circuits associated with emotional processing and regulation. Future studies should aim to further delineate functional and structural connectivity alterations in specific phobia. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

VoxelStats: A MATLAB Package for Multi-Modal Voxel-Wise Brain Image Analysis.

PubMed

Mathotaarachchi, Sulantha; Wang, Seqian; Shin, Monica; Pascoal, Tharick A; Benedet, Andrea L; Kang, Min Su; Beaudry, Thomas; Fonov, Vladimir S; Gauthier, Serge; Labbe, Aurélie; Rosa-Neto, Pedro

2016-01-01

In healthy individuals, behavioral outcomes are highly associated with the variability on brain regional structure or neurochemical phenotypes. Similarly, in the context of neurodegenerative conditions, neuroimaging reveals that cognitive decline is linked to the magnitude of atrophy, neurochemical declines, or concentrations of abnormal protein aggregates across brain regions. However, modeling the effects of multiple regional abnormalities as determinants of cognitive decline at the voxel level remains largely unexplored by multimodal imaging research, given the high computational cost of estimating regression models for every single voxel from various imaging modalities. VoxelStats is a voxel-wise computational framework to overcome these computational limitations and to perform statistical operations on multiple scalar variables and imaging modalities at the voxel level. VoxelStats package has been developed in Matlab(®) and supports imaging formats such as Nifti-1, ANALYZE, and MINC v2. Prebuilt functions in VoxelStats enable the user to perform voxel-wise general and generalized linear models and mixed effect models with multiple volumetric covariates. Importantly, VoxelStats can recognize scalar values or image volumes as response variables and can accommodate volumetric statistical covariates as well as their interaction effects with other variables. Furthermore, this package includes built-in functionality to perform voxel-wise receiver operating characteristic analysis and paired and unpaired group contrast analysis. Validation of VoxelStats was conducted by comparing the linear regression functionality with existing toolboxes such as glim_image and RMINC. The validation results were identical to existing methods and the additional functionality was demonstrated by generating feature case assessments (t-statistics, odds ratio, and true positive rate maps). In summary, VoxelStats expands the current methods for multimodal imaging analysis by allowing the

Structural neural correlates of multitasking: A voxel-based morphometry study.

PubMed

Zhang, Rui-Ting; Yang, Tian-Xiao; Wang, Yi; Sui, Yuxiu; Yao, Jingjing; Zhang, Chen-Yuan; Cheung, Eric F C; Chan, Raymond C K

2016-12-01

Multitasking refers to the ability to organize assorted tasks efficiently in a short period of time, which plays an important role in daily life. However, the structural neural correlates of multitasking performance remain unclear. The present study aimed at exploring the brain regions associated with multitasking performance using global correlation analysis. Twenty-six healthy participants first underwent structural brain scans and then performed the modified Six Element Test, which required participants to attempt six subtasks in 10 min while obeying a specific rule. Voxel-based morphometry of the whole brain was used to detect the structural correlates of multitasking ability. Grey matter volume of the anterior cingulate cortex (ACC) was positively correlated with the overall performance and time monitoring in multitasking. In addition, white matter volume of the anterior thalamic radiation (ATR) was also positively correlated with time monitoring during multitasking. Other related brain regions associated with multitasking included the superior frontal gyrus, the inferior occipital gyrus, the lingual gyrus, and the inferior longitudinal fasciculus. No significant correlation was found between grey matter volume of the prefrontal cortex (Brodmann Area 10) and multitasking performance. Using a global correlation analysis to examine various aspects of multitasking performance, this study provided new insights into the structural neural correlates of multitasking ability. In particular, the ACC was identified as an important brain region that played both a general and a specific time-monitoring role in multitasking, extending the role of the ACC from lesioned populations to healthy populations. The present findings also support the view that the ATR may influence multitasking performance by affecting time-monitoring abilities. © 2016 The Institute of Psychology, Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Grey matter damage in progressive multiple sclerosis versus amyotrophic lateral sclerosis: a voxel-based morphometry MRI study.

PubMed

Tavazzi, Eleonora; Laganà, Maria Marcella; Bergsland, Niels; Tortorella, Paola; Pinardi, Giovanna; Lunetta, Christian; Corbo, Massimo; Rovaris, Marco

2015-03-01

Primary progressive multiple sclerosis (PPMS) and amyotrophic lateral sclerosis (ALS) seem to share some clinical and pathological features. MRI studies revealed the presence of grey matter (GM) atrophy in both diseases, but no comparative data are available. The objective was to compare the regional patterns of GM tissue loss in PPMS and ALS with voxel-based morphometry (VBM). Eighteen PPMS patients, 20 ALS patients, and 31 healthy controls (HC) were studied with a 1.5 Tesla scanner. VBM was performed to assess volumetric GM differences with age and sex as covariates. Threshold-free cluster enhancement analysis was used to obtain significant clusters. Group comparisons were tested with family-wise error correction for multiple comparisons (p < 0.05) except for HC versus MND which was tested at a level of p < 0.001 uncorrected and a cluster threshold of 20 contiguous voxels. Compared to HC, ALS patients showed GM tissue reduction in selected frontal and temporal areas, while PPMS patients showed a widespread bilateral GM volume decrease, involving both deep and cortical regions. Compared to ALS, PPMS patients showed tissue volume reductions in both deep and cortical GM areas. This preliminary study confirms that PPMS is characterized by a more diffuse cortical and subcortical GM atrophy than ALS and that, in the latter condition, brain damage is present outside the motor system. These results suggest that PPMS and ALS may share pathological features leading to GM tissue loss.

Neural correlates of post-conventional moral reasoning: a voxel-based morphometry study.

PubMed

Prehn, Kristin; Korczykowski, Marc; Rao, Hengyi; Fang, Zhuo; Detre, John A; Robertson, Diana C

2015-01-01

Going back to Kohlberg, moral development research affirms that people progress through different stages of moral reasoning as cognitive abilities mature. Individuals at a lower level of moral reasoning judge moral issues mainly based on self-interest (personal interests schema) or based on adherence to laws and rules (maintaining norms schema), whereas individuals at the post-conventional level judge moral issues based on deeper principles and shared ideals. However, the extent to which moral development is reflected in structural brain architecture remains unknown. To investigate this question, we used voxel-based morphometry and examined the brain structure in a sample of 67 Master of Business Administration (MBA) students. Subjects completed the Defining Issues Test (DIT-2) which measures moral development in terms of cognitive schema preference. Results demonstrate that subjects at the post-conventional level of moral reasoning were characterized by increased gray matter volume in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex, compared with subjects at a lower level of moral reasoning. Our findings support an important role for both cognitive and emotional processes in moral reasoning and provide first evidence for individual differences in brain structure according to the stages of moral reasoning first proposed by Kohlberg decades ago.

Neural Correlates of Post-Conventional Moral Reasoning: A Voxel-Based Morphometry Study

PubMed Central

Prehn, Kristin; Korczykowski, Marc; Rao, Hengyi; Fang, Zhuo; Detre, John A.; Robertson, Diana C.

2015-01-01

Going back to Kohlberg, moral development research affirms that people progress through different stages of moral reasoning as cognitive abilities mature. Individuals at a lower level of moral reasoning judge moral issues mainly based on self-interest (personal interests schema) or based on adherence to laws and rules (maintaining norms schema), whereas individuals at the post-conventional level judge moral issues based on deeper principles and shared ideals. However, the extent to which moral development is reflected in structural brain architecture remains unknown. To investigate this question, we used voxel-based morphometry and examined the brain structure in a sample of 67 Master of Business Administration (MBA) students. Subjects completed the Defining Issues Test (DIT-2) which measures moral development in terms of cognitive schema preference. Results demonstrate that subjects at the post-conventional level of moral reasoning were characterized by increased gray matter volume in the ventromedial prefrontal cortex and subgenual anterior cingulate cortex, compared with subjects at a lower level of moral reasoning. Our findings support an important role for both cognitive and emotional processes in moral reasoning and provide first evidence for individual differences in brain structure according to the stages of moral reasoning first proposed by Kohlberg decades ago. PMID:26039547

Gait Analysis Using Wearable Sensors

PubMed Central

Tao, Weijun; Liu, Tao; Zheng, Rencheng; Feng, Hutian

2012-01-01

Gait analysis using wearable sensors is an inexpensive, convenient, and efficient manner of providing useful information for multiple health-related applications. As a clinical tool applied in the rehabilitation and diagnosis of medical conditions and sport activities, gait analysis using wearable sensors shows great prospects. The current paper reviews available wearable sensors and ambulatory gait analysis methods based on the various wearable sensors. After an introduction of the gait phases, the principles and features of wearable sensors used in gait analysis are provided. The gait analysis methods based on wearable sensors is divided into gait kinematics, gait kinetics, and electromyography. Studies on the current methods are reviewed, and applications in sports, rehabilitation, and clinical diagnosis are summarized separately. With the development of sensor technology and the analysis method, gait analysis using wearable sensors is expected to play an increasingly important role in clinical applications. PMID:22438763

Cerebral morphology and dopamine D2/D3receptor distribution in humans: A combined [18F]fallypride and voxel-based morphometry study

PubMed Central

Woodward, Neil D.; Zald, David H.; Ding, Zhaohua; Riccardi, Patrizia; Ansari, M. Sib; Baldwin, Ronald M.; Cowan, Ronald L.; Li, Rui; Kessler, Robert M.

2009-01-01

The relationship between cerebral morphology and the expression of dopamine receptors has not been extensively studied in humans. Elucidation of such relationships may have important methodological implications for clinical studies of dopamine receptor ligand binding differences between control and patient groups. The association between cerebral morphology and dopamine receptor distribution was examined in 45 healthy subjects who completed T1-weighted structural MRI and PET scanning with the D2/D3 ligand [18F]fallypride. Optimized voxel-based morphometry was used to create grey matter volume and density images. Grey matter volume and density images were correlated with binding potential (BPND) images on a voxel-by-voxel basis using the Biological Parametric Mapping toolbox. Associations between cerebral morphology and BPND were also examined for selected regions-of-interest (ROIs) after spatial normalization. Voxel-wise analyses indicated that grey matter volume and density positively correlated with BPND throughout the midbrain, including the substantia nigra. Positive correlations were observed in medial cortical areas, including anterior cingulate and medial prefrontal cortex, and circumscribed regions of the temporal, frontal, and parietal lobes. ROI analyses revealed significant positive correlations between BPND and cerebral morphology in the caudate, thalamus, and amygdala. Few negative correlations between morphology and BPND were observed. Overall, grey matter density appeared more strongly correlated with BPND than grey matter volume. Cerebral morphology, particularly grey matter density, correlates with [18F]fallypride BPND in a regionally specific manner. Clinical studies comparing dopamine receptor availability between clinical and control groups may benefit by accounting for potential differences in cerebral morphology that exist even after spatial normalization. PMID:19457373

Cerebral morphology and dopamine D2/D3 receptor distribution in humans: a combined [18F]fallypride and voxel-based morphometry study.

PubMed

Woodward, Neil D; Zald, David H; Ding, Zhaohua; Riccardi, Patrizia; Ansari, M Sib; Baldwin, Ronald M; Cowan, Ronald L; Li, Rui; Kessler, Robert M

2009-05-15

The relationship between cerebral morphology and the expression of dopamine receptors has not been extensively studied in humans. Elucidation of such relationships may have important methodological implications for clinical studies of dopamine receptor ligand binding differences between control and patient groups. The association between cerebral morphology and dopamine receptor distribution was examined in 45 healthy subjects who completed T1-weighted structural MRI and PET scanning with the D(2)/D(3) ligand [(18)F]fallypride. Optimized voxel-based morphometry was used to create grey matter volume and density images. Grey matter volume and density images were correlated with binding potential (BP(ND)) images on a voxel-by-voxel basis using the Biological Parametric Mapping toolbox. Associations between cerebral morphology and BP(ND) were also examined for selected regions-of-interest (ROIs) after spatial normalization. Voxel-wise analyses indicated that grey matter volume and density positively correlated with BP(ND) throughout the midbrain, including the substantia nigra. Positive correlations were observed in medial cortical areas, including anterior cingulate and medial prefrontal cortex, and circumscribed regions of the temporal, frontal, and parietal lobes. ROI analyses revealed significant positive correlations between BP(ND) and cerebral morphology in the caudate, thalamus, and amygdala. Few negative correlations between morphology and BP(ND) were observed. Overall, grey matter density appeared more strongly correlated with BP(ND) than grey matter volume. Cerebral morphology, particularly grey matter density, correlates with [(18)F]fallypride BP(ND) in a regionally specific manner. Clinical studies comparing dopamine receptor availability between clinical and control groups may benefit by accounting for potential differences in cerebral morphology that exist even after spatial normalization.

Vision-based gait impairment analysis for aided diagnosis.

PubMed

Ortells, Javier; Herrero-Ezquerro, María Trinidad; Mollineda, Ramón A

2018-02-12

Gait is a firsthand reflection of health condition. This belief has inspired recent research efforts to automate the analysis of pathological gait, in order to assist physicians in decision-making. However, most of these efforts rely on gait descriptions which are difficult to understand by humans, or on sensing technologies hardly available in ambulatory services. This paper proposes a number of semantic and normalized gait features computed from a single video acquired by a low-cost sensor. Far from being conventional spatio-temporal descriptors, features are aimed at quantifying gait impairment, such as gait asymmetry from several perspectives or falling risk. They were designed to be invariant to frame rate and image size, allowing cross-platform comparisons. Experiments were formulated in terms of two databases. A well-known general-purpose gait dataset is used to establish normal references for features, while a new database, introduced in this work, provides samples under eight different walking styles: one normal and seven impaired patterns. A number of statistical studies were carried out to prove the sensitivity of features at measuring the expected pathologies, providing enough evidence about their accuracy. Graphical Abstract Graphical abstract reflecting main contributions of the manuscript: at the top, a robust, semantic and easy-to-interpret feature set to describe impaired gait patterns; at the bottom, a new dataset consisting of video-recordings of a number of volunteers simulating different patterns of pathological gait, where features were statistically assessed.

2.5D multi-view gait recognition based on point cloud registration.

PubMed

Tang, Jin; Luo, Jian; Tjahjadi, Tardi; Gao, Yan

2014-03-28

This paper presents a method for modeling a 2.5-dimensional (2.5D) human body and extracting the gait features for identifying the human subject. To achieve view-invariant gait recognition, a multi-view synthesizing method based on point cloud registration (MVSM) to generate multi-view training galleries is proposed. The concept of a density and curvature-based Color Gait Curvature Image is introduced to map 2.5D data onto a 2D space to enable data dimension reduction by discrete cosine transform and 2D principle component analysis. Gait recognition is achieved via a 2.5D view-invariant gait recognition method based on point cloud registration. Experimental results on the in-house database captured by a Microsoft Kinect camera show a significant performance gain when using MVSM.

2.5D Multi-View Gait Recognition Based on Point Cloud Registration

PubMed Central

Tang, Jin; Luo, Jian; Tjahjadi, Tardi; Gao, Yan

2014-01-01

This paper presents a method for modeling a 2.5-dimensional (2.5D) human body and extracting the gait features for identifying the human subject. To achieve view-invariant gait recognition, a multi-view synthesizing method based on point cloud registration (MVSM) to generate multi-view training galleries is proposed. The concept of a density and curvature-based Color Gait Curvature Image is introduced to map 2.5D data onto a 2D space to enable data dimension reduction by discrete cosine transform and 2D principle component analysis. Gait recognition is achieved via a 2.5D view-invariant gait recognition method based on point cloud registration. Experimental results on the in-house database captured by a Microsoft Kinect camera show a significant performance gain when using MVSM. PMID:24686727

Interpreting sources of variation in clinical gait analysis: A case study.

PubMed

King, Stephanie L; Barton, Gabor J; Ranganath, Lakshminarayan R

2017-02-01

To illustrate and discuss sources of gait deviations (experimental, genuine and intentional) during a gait analysis and how these deviations inform clinical decision making. A case study of a 24-year old male diagnosed with Alkaptonuria undergoing a routine gait analysis. A 3D motion capture with the Helen-Hayes marker set was used to quantify lower-limb joint kinematics during barefoot walking along a 10m walkway at a self-selected pace. Additional 2D video data were recorded in the sagittal and frontal plane. The patient reported no aches or pains in any joint and described his lifestyle as active. Temporal-spatial parameters were within normal ranges for his age and sex. Three sources of gait deviations were identified; the posteriorly rotated pelvis was due to an experimental error and marker misplacement, the increased rotation of the pelvis in the horizontal plane was genuine and observed in both 3D gait curves and in 2D video analysis, finally the inconsistency in knee flexion/extension combined with a seemingly innocuous interest in the consequences of abnormal gait suggested an intentional gait deviation. Gait analysis is an important analytical tool in the management of a variety of conditions that negatively impact on movement. Experienced gait analysts have the ability to recognise genuine gait adaptations that forms part of the decision-making process for that patient. However, their role also necessitates the ability to identify and correct for experimental errors and critically evaluate when a deviation may not be genuine. Copyright © 2016 Elsevier B.V. All rights reserved.

Self-esteem recognition based on gait pattern using Kinect.

PubMed

Sun, Bingli; Zhang, Zhan; Liu, Xingyun; Hu, Bin; Zhu, Tingshao

2017-10-01

Self-esteem is an important aspect of individual's mental health. When subjects are not able to complete self-report questionnaire, behavioral assessment will be a good supplement. In this paper, we propose to use gait data collected by Kinect as an indicator to recognize self-esteem. 178 graduate students without disabilities participate in our study. Firstly, all participants complete the 10-item Rosenberg Self-Esteem Scale (RSS) to acquire self-esteem score. After completing the RRS, each participant walks for two minutes naturally on a rectangular red carpet, and the gait data are recorded using Kinect sensor. After data preprocessing, we extract a few behavioral features to train predicting model by machine learning. Based on these features, we build predicting models to recognize self-esteem. For self-esteem prediction, the best correlation coefficient between predicted score and self-report score is 0.45 (p<0.001). We divide the participants according to gender, and for males, the correlation coefficient is 0.43 (p<0.001), for females, it is 0.59 (p<0.001). Using gait data captured by Kinect sensor, we find that the gait pattern could be used to recognize self-esteem with a fairly good criterion validity. The gait predicting model can be taken as a good supplementary method to measure self-esteem. Copyright © 2017 Elsevier B.V. All rights reserved.

Gray matter abnormalities associated with fibromyalgia: A meta-analysis of voxel-based morphometric studies.

PubMed

Shi, HaiCun; Yuan, CongHu; Dai, ZhenYu; Ma, HaiRong; Sheng, LiQin

2016-12-01

Studies employing voxel-based morphometry (VBM) have reported inconsistent findings on the association of gray matter (GM) abnormalities with fibromyalgia. The aim of the present study is to identify the most prominent and replicable GM areas that involved in fibromyalgia. A systematic search of the PubMed database from January 2000 to September 2015 was performed to identify eligible whole-brain VBM studies. Comprehensive meta-analyses to investigate regional GM abnormalities in fibromyalgia were conducted with the Seed-based d Mapping software package. Seven studies, reporting nine comparisons and including a grand total of 180 fibromyalgia patients and 126 healthy controls, were included in the meta-analyses. In fibromyalgia patients compared with healthy controls, regional GM decreases were consistently found in the bilateral anterior cingulate/paracingulate cortex/medial prefrontal cortex, the bilateral posterior cingulate/paracingulate cortex, the left parahippocampal gyrus/fusiform cortex, and the right parahippocampal gyrus/hippocampus. Regional GM increases were consistently found in the left cerebellum. Meta-regression demonstrated that age was correlated with GM anomalies in fibromyalgia patients. The current meta-analysis identified a characteristic pattern of GM alterations within the medial pain system, default mode network, and cerebro-cerebellar circuits, which further supports the concept that fibromyalgia is a symptom complex involving brain areas beyond those implicated in chronic pain. Copyright © 2016 Elsevier Inc. All rights reserved.

Gray matter alteration in isolated congenital anosmia patient: a voxel-based morphometry study.

PubMed

Yao, Linyin; Yi, Xiaoli; Wei, Yongxiang

2013-09-01

Decreased volume of gray matter (GM) was observed in olfactory loss in patients with neurodegenerative disorder. However, GM volume has not yet been investigated in isolated congenital anosmia (ICA) people. We herewith investigated the volume change of gray matter of an ICA boy by morphometric analysis of magnetic resonance images (voxel-based morphometry), and compared with that of 20 age-matched healthy controls. ICA boy presented a significant decrease in GM volume in the orbitofrontal cortex, anterior cingulate cortex, middle cingulate cortex, thalamus, insular cortex, cerebellum, precuneus, gyrus rectus, subcallosal gyrus, middle temporal gyrus, fusiform gyrus and piriform cortex. No significant GM volume increase was detected in other brain areas. The pattern of GM atrophy was similar as previous literature reported. Our results identified similar GM volume alterations regardless of the causes of olfactory impairment. Decreased GM volume was not only shown in olfactory bulbs, olfactory tracts and olfactory sulcus, also in primary olfactory cortex and the secondary cerebral olfactory areas in ICA people. This is the first study to evaluate GM volume alterations in ICA people.

Accelerometry-based gait analysis, an additional objective approach to screen subjects at risk for falling.

PubMed

Senden, R; Savelberg, H H C M; Grimm, B; Heyligers, I C; Meijer, K

2012-06-01

This study investigated whether the Tinetti scale, as a subjective measure for fall risk, is associated with objectively measured gait characteristics. It is studied whether gait parameters are different for groups that are stratified for fall risk using the Tinetti scale. Moreover, the discriminative power of gait parameters to classify elderly according to the Tinetti scale is investigated. Gait of 50 elderly with a Tinneti>24 and 50 elderly with a Tinetti≤24 was analyzed using acceleration-based gait analysis. Validated algorithms were used to derive spatio-temporal gait parameters, harmonic ratio, inter-stride amplitude variability and root mean square (RMS) from the accelerometer data. Clear differences in gait were found between the groups. All gait parameters correlated with the Tinetti scale (r-range: 0.20-0.73). Only walking speed, step length and RMS showed moderate to strong correlations and high discriminative power to classify elderly according to the Tinetti scale. It is concluded that subtle gait changes that have previously been related to fall risk are not captured by the subjective assessment. It is therefore worthwhile to include objective gait assessment in fall risk screening. Copyright © 2012 Elsevier B.V. All rights reserved.

A voxel-based finite element model for the prediction of bladder deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chai Xiangfei; Herk, Marcel van; Hulshof, Maarten C. C. M.

2012-01-15

Purpose: A finite element (FE) bladder model was previously developed to predict bladder deformation caused by bladder filling change. However, two factors prevent a wide application of FE models: (1) the labor required to construct a FE model with high quality mesh and (2) long computation time needed to construct the FE model and solve the FE equations. In this work, we address these issues by constructing a low-resolution voxel-based FE bladder model directly from the binary segmentation images and compare the accuracy and computational efficiency of the voxel-based model used to simulate bladder deformation with those of a classicalmore » FE model with a tetrahedral mesh. Methods: For ten healthy volunteers, a series of MRI scans of the pelvic region was recorded at regular intervals of 10 min over 1 h. For this series of scans, the bladder volume gradually increased while rectal volume remained constant. All pelvic structures were defined from a reference image for each volunteer, including bladder wall, small bowel, prostate (male), uterus (female), rectum, pelvic bone, spine, and the rest of the body. Four separate FE models were constructed from these structures: one with a tetrahedral mesh (used in previous study), one with a uniform hexahedral mesh, one with a nonuniform hexahedral mesh, and one with a low-resolution nonuniform hexahedral mesh. Appropriate material properties were assigned to all structures and uniform pressure was applied to the inner bladder wall to simulate bladder deformation from urine inflow. Performance of the hexahedral meshes was evaluated against the performance of the standard tetrahedral mesh by comparing the accuracy of bladder shape prediction and computational efficiency. Results: FE model with a hexahedral mesh can be quickly and automatically constructed. No substantial differences were observed between the simulation results of the tetrahedral mesh and hexahedral meshes (<1% difference in mean dice similarity

Predicting drought propagation within peat layers using a three dimensionally explicit voxel based model

NASA Astrophysics Data System (ADS)

Condro, A. A.; Pawitan, H.; Risdiyanto, I.

2018-05-01

Peatlands are very vulnerable to widespread fires during dry seasons, due to availability of aboveground fuel biomass on the surface and belowground fuel biomass on the sub-surface. Hence, understanding drought propagation occurring within peat layers is crucial with regards to disaster mitigation activities on peatlands. Using a three dimensionally explicit voxel-based model of peatland hydrology, this study predicted drought propagation time lags into sub-surface peat layers after drought events occurrence on the surface of about 1 month during La-Nina and 2.5 months during El-Nino. The study was carried out on a high-conservation-value area of oil palm plantation in West Kalimantan. Validity of the model was evaluated and its applicability for disaster mitigation was discussed. The animations of simulated voxels are available at: goo.gl/HDRMYN (El-Nino 2015 episode) and goo.gl/g1sXPl (La-Nina 2016 episode). The model is available at: goo.gl/RiuMQz.

Gait and footwear in children and adolescents with Charcot-Marie-Tooth disease: A cross-sectional, case-controlled study.

PubMed

Kennedy, Rachel A; McGinley, Jennifer L; Paterson, Kade L; Ryan, Monique M; Carroll, Kate

2018-05-01

Children with Charcot-Marie-Tooth disease (CMT) report problems with gait and footwear. We evaluated differences in spatio-temporal gait variables and gait variability between children with CMT and typically developing (TD) children, and investigated the effect of footwear upon gait. A cross-sectional study of 30 children with CMT and 30 age- and gender-matched TD children aged 4-18 years. Gait was assessed at self-selected speed on an electronic walkway while barefoot and in two types of the child's own footwear; optimal (e.g., athletic-type runners) and suboptimal (e.g., flip-flops). Children with CMT walked more slowly (mean (SD) -13.81 (3.61) cm/s), with shorter steps (-6.28 (1.37) cm), wider base of support (+2.47 (0.66) cm; all p < 0.001) and greater base of support variability (0.48 (0.15) cm, p = 0.002) compared to TD children. Gait was faster in optimal footwear than suboptimal (-7.55 (1.31) cm/s) and barefoot (-7.42 (1.07) cm/sec; both p < 0.001) in the combined group of children. Gait in suboptimal footwear was more variable compared to barefoot and optimal footwear. Greater base of support variability and reduced balance was moderately correlated for both groups (CMT and TD). Gait is slower with shorter, wider steps and greater base of support variability in children with CMT. Poor balance is associated with greater base of support gait variability. Suboptimal footwear negatively affects gait in all children (CMT and TD), which has clinical implications for children and adolescents with CMT who have weaker feet and ankles, and poor balance. Copyright © 2018 Elsevier B.V. All rights reserved.

Different brain structures associated with artistic and scientific creativity: a voxel-based morphometry study.

PubMed

Shi, Baoguo; Cao, Xiaoqing; Chen, Qunlin; Zhuang, Kaixiang; Qiu, Jiang

2017-02-21

Creativity is the ability to produce original and valuable ideas or behaviors. In real life, artistic and scientific creativity promoted the development of human civilization; however, to date, no studies have systematically investigated differences in the brain structures responsible for artistic and scientific creativity in a large sample. Using voxel-based morphometry (VBM), this study identified differences in regional gray matter volume (GMV) across the brain between artistic and scientific creativity (assessed by the Creative Achievement Questionnaire) in 356 young, healthy subjects. The results showed that artistic creativity was significantly negatively associated with the regional GMV of the supplementary motor area (SMA) and anterior cingulate cortex (ACC). In contrast, scientific creativity was significantly positively correlated with the regional GMV of the left middle frontal gyrus (MFG) and left inferior occipital gyrus (IOG). Overall, artistic creativity was associated with the salience network (SN), whereas scientific creativity was associated with the executive attention network and semantic processing. These results may provide an effective marker that can be used to predict and evaluate individuals' creative performance in the fields of science and art.

Different brain structures associated with artistic and scientific creativity: a voxel-based morphometry study

PubMed Central

Shi, Baoguo; Cao, Xiaoqing; Chen, Qunlin; Zhuang, Kaixiang; Qiu, Jiang

2017-01-01

Creativity is the ability to produce original and valuable ideas or behaviors. In real life, artistic and scientific creativity promoted the development of human civilization; however, to date, no studies have systematically investigated differences in the brain structures responsible for artistic and scientific creativity in a large sample. Using voxel-based morphometry (VBM), this study identified differences in regional gray matter volume (GMV) across the brain between artistic and scientific creativity (assessed by the Creative Achievement Questionnaire) in 356 young, healthy subjects. The results showed that artistic creativity was significantly negatively associated with the regional GMV of the supplementary motor area (SMA) and anterior cingulate cortex (ACC). In contrast, scientific creativity was significantly positively correlated with the regional GMV of the left middle frontal gyrus (MFG) and left inferior occipital gyrus (IOG). Overall, artistic creativity was associated with the salience network (SN), whereas scientific creativity was associated with the executive attention network and semantic processing. These results may provide an effective marker that can be used to predict and evaluate individuals’ creative performance in the fields of science and art. PMID:28220826

Evaluation of the performance of accelerometer-based gait event detection algorithms in different real-world scenarios using the MAREA gait database.

PubMed

Khandelwal, Siddhartha; Wickström, Nicholas

2017-01-01

Numerous gait event detection (GED) algorithms have been developed using accelerometers as they allow the possibility of long-term gait analysis in everyday life. However, almost all such existing algorithms have been developed and assessed using data collected in controlled indoor experiments with pre-defined paths and walking speeds. On the contrary, human gait is quite dynamic in the real-world, often involving varying gait speeds, changing surfaces and varying surface inclinations. Though portable wearable systems can be used to conduct experiments directly in the real-world, there is a lack of publicly available gait datasets or studies evaluating the performance of existing GED algorithms in various real-world settings. This paper presents a new gait database called MAREA (n=20 healthy subjects) that consists of walking and running in indoor and outdoor environments with accelerometers positioned on waist, wrist and both ankles. The study also evaluates the performance of six state-of-the-art accelerometer-based GED algorithms in different real-world scenarios, using the MAREA gait database. The results reveal that the performance of these algorithms is inconsistent and varies with changing environments and gait speeds. All algorithms demonstrated good performance for the scenario of steady walking in a controlled indoor environment with a combined median F1score of 0.98 for Heel-Strikes and 0.94 for Toe-Offs. However, they exhibited significantly decreased performance when evaluated in other lesser controlled scenarios such as walking and running in an outdoor street, with a combined median F1score of 0.82 for Heel-Strikes and 0.53 for Toe-Offs. Moreover, all GED algorithms displayed better performance for detecting Heel-Strikes as compared to Toe-Offs, when evaluated in different scenarios. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigating structural brain changes of dehydration using voxel-based morphometry.

PubMed

Streitbürger, Daniel-Paolo; Möller, Harald E; Tittgemeyer, Marc; Hund-Georgiadis, Margret; Schroeter, Matthias L; Mueller, Karsten

2012-01-01

Dehydration can affect the volume of brain structures, which might imply a confound in volumetric and morphometric studies of normal or diseased brain. Six young, healthy volunteers were repeatedly investigated using three-dimensional T(1)-weighted magnetic resonance imaging during states of normal hydration, hyperhydration, and dehydration to assess volume changes in gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). The datasets were analyzed using voxel-based morphometry (VBM), a widely used voxel-wise statistical analysis tool, FreeSurfer, a fully automated volumetric segmentation measure, and SIENAr a longitudinal brain-change detection algorithm. A significant decrease of GM and WM volume associated with dehydration was found in various brain regions, most prominently, in temporal and sub-gyral parietal areas, in the left inferior orbito-frontal region, and in the extra-nuclear region. Moreover, we found consistent increases in CSF, that is, an expansion of the ventricular system affecting both lateral ventricles, the third, and the fourth ventricle. Similar degrees of shrinkage in WM volume and increase of the ventricular system have been reported in studies of mild cognitive impairment or Alzheimer's disease during disease progression. Based on these findings, a potential confound in GM and WM or ventricular volume studies due to the subjects' hydration state cannot be excluded and should be appropriately addressed in morphometric studies of the brain.

Investigating Structural Brain Changes of Dehydration Using Voxel-Based Morphometry

PubMed Central

Streitbürger, Daniel-Paolo; Möller, Harald E.; Tittgemeyer, Marc; Hund-Georgiadis, Margret; Schroeter, Matthias L.; Mueller, Karsten

2012-01-01

Dehydration can affect the volume of brain structures, which might imply a confound in volumetric and morphometric studies of normal or diseased brain. Six young, healthy volunteers were repeatedly investigated using three-dimensional T 1-weighted magnetic resonance imaging during states of normal hydration, hyperhydration, and dehydration to assess volume changes in gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). The datasets were analyzed using voxel-based morphometry (VBM), a widely used voxel-wise statistical analysis tool, FreeSurfer, a fully automated volumetric segmentation measure, and SIENAr a longitudinal brain-change detection algorithm. A significant decrease of GM and WM volume associated with dehydration was found in various brain regions, most prominently, in temporal and sub-gyral parietal areas, in the left inferior orbito-frontal region, and in the extra-nuclear region. Moreover, we found consistent increases in CSF, that is, an expansion of the ventricular system affecting both lateral ventricles, the third, and the fourth ventricle. Similar degrees of shrinkage in WM volume and increase of the ventricular system have been reported in studies of mild cognitive impairment or Alzheime s disease during disease progression. Based on these findings, a potential confound in GM and WM or ventricular volume studies due to the subjects’ hydration state cannot be excluded and should be appropriately addressed in morphometric studies of the brain. PMID:22952926

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.

A mechanized gait trainer for restoration of gait.

PubMed

Hesse, S; Uhlenbrock, D

2000-01-01

The newly developed gait trainer allows wheel-chair-bound subjects the repetitive practice of a gait-like movement without overstressing therapists. The device simulates the phases of gait, supports the subjects according to their abilities, and controls the center of mass (CoM) in the vertical and horizontal directions. The patterns of sagittal lower limb joint kinematics and of muscle activation for a normal subject were similar when using the mechanized trainer and when walking on a treadmill. A non-ambulatory hemiparetic subject required little help from one therapist on the gait trainer, while two therapists were required to support treadmill walking. Gait movements on the trainer were highly symmetrical, impact free, and less spastic. The vertical displacement of the CoM was bi-phasic instead of mono-phasic during each gait cycle on the new device. Two cases of non-ambulatory patients, who regained their walking ability after 4 weeks of daily training on the gait trainer, are reported.

MAX meets ADAM: a dosimetric comparison between a voxel-based and a mathematical model for external exposure to photons

NASA Astrophysics Data System (ADS)

Kramer, R.; Vieira, J. W.; Khoury, H. J.; Lima, F. de Andrade

2004-03-01

The International Commission on Radiological Protection intends to revise the organ and tissue equivalent dose conversion coefficients published in various reports. For this purpose the mathematical human medical internal radiation dose (MIRD) phantoms, actually in use, have to be replaced by recently developed voxel-based phantoms. This study investigates the dosimetric consequences, especially with respect to the effective male dose, if not only a MIRD phantom is replaced by a voxel phantom, but also if the tissue compositions and the radiation transport codes are changed. This task will be resolved by systematically replacing in the mathematical ADAM/GSF exposure model, first the radiation transport code, then the tissue composition and finally the phantom anatomy, in order to arrive at the voxel-based MAX/EGS4 exposure model. The results show that the combined effect of these replacements can decrease the effective male dose by up to 25% for external exposures to photons for incident energies above 30 keV for different field geometries, mainly because of increased shielding by a heterogeneous skeleton and by the overlying adipose and muscle tissue, and also because of the positions internal organs have in a realistically designed human body compared to their positions in the mathematically constructed phantom.

Respective and combined effects of impairments in sensorimotor systems and cognition on gait performance: a population-based cross-sectional study.

PubMed

Beauchet, Olivier; Launay, Cyrille P; Fantino, Bruno; Allali, Gilles; Annweiler, Cédric

2015-01-01

Respective and combined effects of impairments in sensorimotor systems and cognition on gait performance have not been fully studied. This study aims to describe the respective effects of impairments in muscle strength, distance vision, lower-limb proprioception and cognition on the Timed Up & Go (TUG) scores (i.e., performed TUG [pTUG], imagined TUG [iTUG] and the time difference between these two tests [delta TUG]) in older community-dwellers; and to examine their combined effects on TUG scores. Based on a cross-sectional design, 1792 community-dwellers (70.2 ± 4.8 years; 53.6% female) were recruited. Gait performance was assessed using pTUG, iTUG and delta TUG. Participants were divided into healthy individuals and 15 subgroups of individuals according to the presence of impairment in one or more subsystems involved in gait control (i.e., muscle strength and/or distance vision and/or lower-limb proprioception and/or cognition [episodic memory and executive performance]). Impairment in muscle strength, distance vision and lower-limb proprioception was defined as being in the lowest tertile of performance. Impairment in cognition was defined as abnormal episodic memory and executive tests. A total of 191 (10.7%) exhibited impairment in muscle strength, 188 (10.5%) in distance vision, 302 (16.9%) in lower-limb proprioception, and 42 (2.3%) in cognition. Linear regressions showed that cognitive impairment as well as dual combinations of impairments were associated with increased pTUG (P<0.02). Impairment in lower-limb proprioception was associated with decreased iTUG (P=0.015). All combinations of impairments, except those including muscle strength and the combinations of the 4 subsystems, were associated with increased delta TUG (P<0.04). Cognitive integrity is central for efficient gait control and stability, whereas lower-limb proprioception seems to be central for gait imagery.

Blood pressure, gait speed, and mortality in very old individuals: a population-based cohort study.

PubMed

Weidung, Bodil; Boström, Gustaf; Toots, Annika; Nordström, Peter; Carlberg, Bo; Gustafson, Yngve; Littbrand, Håkan

2015-03-01

Clinical trials and observational studies have produced contradictory results regarding the association of blood pressure (BP) and mortality in people aged 80 years or older. Gait speed at usual pace has been shown to moderate this association in a population of noninstitutionalized people aged 65 years or older. The aims of this study were to investigate the association of BP with all-cause mortality in a representative sample of people aged 85 years or older and to assess whether gait speed moderates this association. A total of 806 participants in the population-based prospective Umeå 85+/GERDA study aged 85, 90, and 95 years or older. Gait speed at usual pace was measured over 2.4 m. The main outcome was hazard ratios (HRs) for all-cause mortality according to systolic and diastolic BP categories in the total sample and in faster-walking (≥0.5 m/s, n = 312) and slower-walking (<0.5 m/s, n = 433) subcohorts; the latter also included habitually nonwalking participants. Comprehensive adjustments were made for sociodemographic and clinical characteristics associated with death. Mean age and baseline systolic and diastolic BP were 89.6 ± 4.6 years, 146.8 ± 23.9 mm Hg, and 74.8 ± 11.1 mm Hg, respectively. Most (n = 561 [69%]) participants were women, 315 (39%) were care facility residents, and 566 (70%) were prescribed BP-lowering drugs. Within 5 years, 490 (61%) participants died. In the total sample and slower-walking subcohort, systolic BP appeared to be inversely associated with mortality, although not independent of adjustments. Among faster-walking participants, mortality risk after adjustment was more than 2 times higher in those with systolic BP of 140 to 149 mm Hg (HR = 2.25, 95% confidence interval [CI] = 1.03-4.94) and 165 mm Hg or higher (HR = 2.13, 95% CI = 1.01-4.49), compared with systolic BP of 126 to 139 mm Hg. Mortality risk was also independently higher in faster-walking participants with diastolic BP higher than 80 mm Hg, compared with

Flexible Piezoelectric Sensor-Based Gait Recognition.

PubMed

Cha, Youngsu; Kim, Hojoon; Kim, Doik

2018-02-05

Most motion recognition research has required tight-fitting suits for precise sensing. However, tight-suit systems have difficulty adapting to real applications, because people normally wear loose clothes. In this paper, we propose a gait recognition system with flexible piezoelectric sensors in loose clothing. The gait recognition system does not directly sense lower-body angles. It does, however, detect the transition between standing and walking. Specifically, we use the signals from the flexible sensors attached to the knee and hip parts on loose pants. We detect the periodic motion component using the discrete time Fourier series from the signal during walking. We adapt the gait detection method to a real-time patient motion and posture monitoring system. In the monitoring system, the gait recognition operates well. Finally, we test the gait recognition system with 10 subjects, for which the proposed system successfully detects walking with a success rate over 93 %.

A Grassmann graph embedding framework for gait analysis

NASA Astrophysics Data System (ADS)

Connie, Tee; Goh, Michael Kah Ong; Teoh, Andrew Beng Jin

2014-12-01

Gait recognition is important in a wide range of monitoring and surveillance applications. Gait information has often been used as evidence when other biometrics is indiscernible in the surveillance footage. Building on recent advances of the subspace-based approaches, we consider the problem of gait recognition on the Grassmann manifold. We show that by embedding the manifold into reproducing kernel Hilbert space and applying the mechanics of graph embedding on such manifold, significant performance improvement can be obtained. In this work, the gait recognition problem is studied in a unified way applicable for both supervised and unsupervised configurations. Sparse representation is further incorporated in the learning mechanism to adaptively harness the local structure of the data. Experiments demonstrate that the proposed method can tolerate variations in appearance for gait identification effectively.

Detecting gait abnormalities after concussion or mild traumatic brain injury: A systematic review of single-task, dual-task, and complex gait.

PubMed

Fino, Peter C; Parrington, Lucy; Pitt, Will; Martini, Douglas N; Chesnutt, James C; Chou, Li-Shan; King, Laurie A

2018-05-01

While a growing number of studies have investigated the effects of concussion or mild traumatic brain injury (mTBI) on gait, many studies use different experimental paradigms and outcome measures. The path for translating experimental studies for objective clinical assessments of gait is unclear. This review asked 2 questions: 1) is gait abnormal after concussion/mTBI, and 2) what gait paradigms (single-task, dual-task, complex gait) detect abnormalities after concussion. Data sources included MEDLINE/PubMed, Scopus, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) accessed on March 14, 2017. Original research articles reporting gait outcomes in people with concussion or mTBI were included. Studies of moderate, severe, or unspecified TBI, and studies without a comparator were excluded. After screening 233 articles, 38 studies were included and assigned to one or more sections based on the protocol and reported outcomes. Twenty-six articles reported single-task simple gait outcomes, 24 reported dual-task simple gait outcomes, 21 reported single-task complex gait outcomes, and 10 reported dual-task complex gait outcomes. Overall, this review provides evidence for two conclusions: 1) gait is abnormal acutely after concussion/mTBI but generally resolves over time; and 2) the inconsistency of findings, small sample sizes, and small number of studies examining homogenous measures at the same time-period post-concussion highlight the need for replication across independent populations and investigators. Future research should concentrate on dual-task and complex gait tasks, as they showed promise for detecting abnormal locomotor function outside of the acute timeframe. Additionally, studies should provide detailed demographic and clinical characteristics to enable more refined comparisons across studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Mobile Phone-Based Measures of Activity, Step Count, and Gait Speed: Results From a Study of Older Ambulatory Adults in a Naturalistic Setting

PubMed Central

Aung, Thawda; Whittington, Jackie; High, Robin R; Goulding, Evan H; Schenk, A Katrin

2017-01-01

Background Cellular mobile telephone technology shows much promise for delivering and evaluating healthcare interventions in cost-effective manners with minimal barriers to access. There is little data demonstrating that these devices can accurately measure clinically important aspects of individual functional status in naturalistic environments outside of the laboratory. Objective The objective of this study was to demonstrate that data derived from ubiquitous mobile phone technology, using algorithms developed and previously validated by our lab in a controlled setting, can be employed to continuously and noninvasively measure aspects of participant (subject) health status including step counts, gait speed, and activity level, in a naturalistic community setting. A second objective was to compare our mobile phone-based data against current standard survey-based gait instruments and clinical physical performance measures in order to determine whether they measured similar or independent constructs. Methods A total of 43 ambulatory, independently dwelling older adults were recruited from Nebraska Medicine, including 25 (58%, 25/43) healthy control individuals from our Engage Wellness Center and 18 (42%, 18/43) functionally impaired, cognitively intact individuals (who met at least 3 of 5 criteria for frailty) from our ambulatory Geriatrics Clinic. The following previously-validated surveys were obtained on study day 1: (1) Late Life Function and Disability Instrument (LLFDI); (2) Survey of Activities and Fear of Falling in the Elderly (SAFFE); (3) Patient Reported Outcomes Measurement Information System (PROMIS), short form version 1.0 Physical Function 10a (PROMIS-PF); and (4) PROMIS Global Health, short form version 1.1 (PROMIS-GH). In addition, clinical physical performance measurements of frailty (10 foot Get up and Go, 4 Meter walk, and Figure-of-8 Walk [F8W]) were also obtained. These metrics were compared to our mobile phone-based metrics collected from the

Gait Training Interventions for Lower Extremity Amputees: A Systematic Literature Review

PubMed Central

Highsmith, M. Jason; Andrews, Casey R.; Millman, Claire; Fuller, Ashley; Kahle, Jason T.; Klenow, Tyler D.; Lewis, Katherine L.; Bradley, Rachel C.; Orriola, John J.

2016-01-01

Lower extremity (LE) amputation patients who use prostheses have gait asymmetries and altered limb loading and movement strategies when ambulating. Subsequent secondary conditions are believed to be associated with gait deviations and lead to long-term complications that impact function and quality of life as a result. The purpose of this study was to systematically review the literature to determine the strength of evidence supporting gait training interventions and to formulate evidence statements to guide practice and research related to therapeutic gait training for lower extremity amputees. A systematic review of three databases was conducted followed by evaluation of evidence and synthesis of empirical evidence statements (EES). Eighteen manuscripts were included in the review, which covered two areas of gait training interventions: 1) overground and 2) treadmill-based. Eight EESs were synthesized. Four addressed overground gait training, one covered treadmill training, and three statements addressed both forms of therapy. Due to the gait asymmetries, altered biomechanics, and related secondary consequences associated with LE amputation, gait training interventions are needed along with study of their efficacy. Overground training with verbal or other auditory, manual, and psychological awareness interventions was found to be effective at improving gait. Similarly, treadmill-based training was found to be effective: 1) as a supplement to overground training; 2) independently when augmented with visual feedback and/or body weight support; or 3) as part of a home exercise plan. Gait training approaches studied improved multiple areas of gait, including sagittal and coronal biomechanics, spatiotemporal measures, and distance walked. PMID:28066520

Comparative study of SVM methods combined with voxel selection for object category classification on fMRI data.

PubMed

Song, Sutao; Zhan, Zhichao; Long, Zhiying; Zhang, Jiacai; Yao, Li

2011-02-16

Support vector machine (SVM) has been widely used as accurate and reliable method to decipher brain patterns from functional MRI (fMRI) data. Previous studies have not found a clear benefit for non-linear (polynomial kernel) SVM versus linear one. Here, a more effective non-linear SVM using radial basis function (RBF) kernel is compared with linear SVM. Different from traditional studies which focused either merely on the evaluation of different types of SVM or the voxel selection methods, we aimed to investigate the overall performance of linear and RBF SVM for fMRI classification together with voxel selection schemes on classification accuracy and time-consuming. Six different voxel selection methods were employed to decide which voxels of fMRI data would be included in SVM classifiers with linear and RBF kernels in classifying 4-category objects. Then the overall performances of voxel selection and classification methods were compared. Results showed that: (1) Voxel selection had an important impact on the classification accuracy of the classifiers: in a relative low dimensional feature space, RBF SVM outperformed linear SVM significantly; in a relative high dimensional space, linear SVM performed better than its counterpart; (2) Considering the classification accuracy and time-consuming holistically, linear SVM with relative more voxels as features and RBF SVM with small set of voxels (after PCA) could achieve the better accuracy and cost shorter time. The present work provides the first empirical result of linear and RBF SVM in classification of fMRI data, combined with voxel selection methods. Based on the findings, if only classification accuracy was concerned, RBF SVM with appropriate small voxels and linear SVM with relative more voxels were two suggested solutions; if users concerned more about the computational time, RBF SVM with relative small set of voxels when part of the principal components were kept as features was a better choice.

Treadmill training with partial body weight support and an electromechanical gait trainer for restoration of gait in subacute stroke patients: a randomized crossover study.

PubMed

Werner, C; Von Frankenberg, S; Treig, T; Konrad, M; Hesse, S

2002-12-01

The purpose of this study was to compare treadmill and electromechanical gait trainer therapy in subacute, nonambulatory stroke survivors. The gait trainer was designed to provide nonambulatory subjects the repetitive practice of a gait-like movement without overexerting therapists. This was a randomized, controlled study with a crossover design following an A-B-A versus a B-A-B pattern. A consisted of 2 weeks of gait trainer therapy, and B consisted of 2 weeks of treadmill therapy. Thirty nonambulatory hemiparetic patients, 4 to 12 weeks after stroke, were randomly assigned to 1 of the 2 groups receiving locomotor therapy every workday for 15 to 20 minutes for 6 weeks. Weekly gait ability (functional ambulation category [FAC]), gait velocity, and the required physical assistance during both kinds of locomotor therapy were the primary outcome measures, and other motor functions (Rivermead motor assessment score) and ankle spasticity (modified Ashworth score) were the secondary outcome measures. Follow-up occurred 6 months later. The groups did not differ at study onset with respect to the clinical characteristics and effector variables. During treatment, the FAC, gait velocity, and Rivermead scores improved in both groups, and ankle spasticity did not change. Median FAC level was 4 (3 to 4) in group A compared with 3 (2 to 3) in group B at the end of treatment (P=0.018), but the difference at 6-month follow up was not significant. The therapeutic effort was less on the gait trainer, with 1 instead of 2 therapists assisting the patient at study onset. All but seven patients preferred the gait trainer. The newly developed gait trainer was at least as effective as treadmill therapy with partial body weight support while requiring less input from the therapist. Further studies are warranted.

Motor imagery group practice for gait rehabilitation in individuals with post-stroke hemiparesis: a pilot study.

PubMed

Dickstein, Ruth; Levy, Sandra; Shefi, Sara; Holtzman, Sarit; Peleg, Sara; Vatine, Jean-Jacques

2014-01-01

Stroke is the leading cause of adult disability, with walking impairment being a devastating indicator of chronic post-stroke hemiparesis. Limited resources exist for individual treatments; therefore, the delivery of safe group exercise therapy is highly desired. To examine whether the application of group-based motor imagery practice to community-dwelling individuals with chronic hemiparesis improves gait. Sixteen individuals with chronic hemiparesis from two community centers participated in the study, with eight from each center. Four participants in each center received five weeks of the experimental intervention, consisting of group-based motor imagery exercises of gait tasks, followed by five weeks of control treatment of motor imagery exercises for the affected upper extremity. Four other subjects in each center received the same treatments in reverse order. Pre- and post intervention measurements included clinical and biomechanical gait parameters. Comparisons within (pre- vs. post) and between treatments (experimental vs. control) indicated no significant change in any gait variable. Nevertheless, the verbal reports of most participants alluded to satisfaction with the experimental intervention and to an increase in self-confidence. Despite the lack of evidence for the effectiveness of group-based motor imagery practice in improving gait among individuals with chronic hemiparesis, the contrast between the measured outcomes and the positive verbal reports merits further inquiry.

How distributed processing produces false negatives in voxel-based lesion-deficit analyses.

PubMed

Gajardo-Vidal, Andrea; Lorca-Puls, Diego L; Crinion, Jennifer T; White, Jitrachote; Seghier, Mohamed L; Leff, Alex P; Hope, Thomas M H; Ludersdorfer, Philipp; Green, David W; Bowman, Howard; Price, Cathy J

2018-07-01

In this study, we hypothesized that if the same deficit can be caused by damage to one or another part of a distributed neural system, then voxel-based analyses might miss critical lesion sites because preservation of each site will not be consistently associated with preserved function. The first part of our investigation used voxel-based multiple regression analyses of data from 359 right-handed stroke survivors to identify brain regions where lesion load is associated with picture naming abilities after factoring out variance related to object recognition, semantics and speech articulation so as to focus on deficits arising at the word retrieval level. A highly significant lesion-deficit relationship was identified in left temporal and frontal/premotor regions. Post-hoc analyses showed that damage to either of these sites caused the deficit of interest in less than half the affected patients (76/162 = 47%). After excluding all patients with damage to one or both of the identified regions, our second analysis revealed a new region, in the anterior part of the left putamen, which had not been previously detected because many patients had the deficit of interest after temporal or frontal damage that preserved the left putamen. The results illustrate how (i) false negative results arise when the same deficit can be caused by different lesion sites; (ii) some of the missed effects can be unveiled by adopting an iterative approach that systematically excludes patients with lesions to the areas identified in previous analyses, (iii) statistically significant voxel-based lesion-deficit mappings can be driven by a subset of patients; (iv) focal lesions to the identified regions are needed to determine whether the deficit of interest is the consequence of focal damage or much more extensive damage that includes the identified region; and, finally, (v) univariate voxel-based lesion-deficit mappings cannot, in isolation, be used to predict outcome in other patients

Factors associated with gait speed recovery after total knee arthroplasty: A longitudinal study.

PubMed

Pua, Yong-Hao; Seah, Felicia Jie-Ting; Clark, Ross Allan; Lian-Li Poon, Cheryl; Tan, John Wei-Ming; Chong, Hwei-Chi

2017-04-01

Gait speed limitations can remain significant issues after a total knee arthroplasty (TKA) but their associated factors are not well understood. This study aimed to identify the factors associated with acute gait speed recovery post-TKA. We performed a prospective longitudinal study of 1765 patients who underwent primary TKA between July 2013 and July 2015. At 4, 8, 12, and 16 weeks postsurgery, fast gait speed was measured. The factors associated with gait speed over time since TKA were identified using multivariable generalized least squares modeling. Lower postoperative quadriceps strength and knee flexion range of motion were closely associated with lower gait speed over time (0.084m/s, 0.064m/s, and 0.055m/s change in gait speed per interquartile range change in ipsilateral quadriceps strength, contralateral quadriceps strength, and knee flexion range of motion, respectively). Additional strong predictors of lower gait speed included older age (0.11m/s), lower levels of preoperative Short Form 36 physical function (0.066m/s), greater body mass (0.046m/s), and the preoperative use of a walking aid (overall P < 0.001). Patients who reported that they limited their daily activities due to a fear of falling also had poorer gait speed (0.033m/s and 0.054m/s slower gait speed for "Occasional" and "Often" categories, respectively, vs. "None"). Gait speed recovery post-TKA is driven by both physical and psychological factors, suggesting that identifying and treating the underlying physical and cognitive causes of gait speed limitations may be crucial to optimize functional recovery. Copyright © 2017 Elsevier Inc. All rights reserved.

Gait Characteristic Analysis and Identification Based on the iPhone's Accelerometer and Gyrometer

PubMed Central

Sun, Bing; Wang, Yang; Banda, Jacob

2014-01-01

Gait identification is a valuable approach to identify humans at a distance. In this paper, gait characteristics are analyzed based on an iPhone's accelerometer and gyrometer, and a new approach is proposed for gait identification. Specifically, gait datasets are collected by the triaxial accelerometer and gyrometer embedded in an iPhone. Then, the datasets are processed to extract gait characteristic parameters which include gait frequency, symmetry coefficient, dynamic range and similarity coefficient of characteristic curves. Finally, a weighted voting scheme dependent upon the gait characteristic parameters is proposed for gait identification. Four experiments are implemented to validate the proposed scheme. The attitude and acceleration solutions are verified by simulation. Then the gait characteristics are analyzed by comparing two sets of actual data, and the performance of the weighted voting identification scheme is verified by 40 datasets of 10 subjects. PMID:25222034

Neurofunctional maps of the 'maternal brain' and the effects of oxytocin: a multimodal voxel-based meta-analysis.

PubMed

Rocchetti, Matteo; Radua, Joaquim; Paloyelis, Yannis; Xenaki, Lida-Alkisti; Frascarelli, Marianna; Caverzasi, Edgardo; Politi, Pierluigi; Fusar-Poli, Paolo

2014-10-01

Several studies have tried to understand the possible neurobiological basis of mothering. The putative involvement of oxytocin, in this regard, has been deeply investigated. Performing a voxel-based meta-analysis, we aimed at testing the hypothesis of overlapping brain activation in functional magnetic resonance imaging (fMRI) studies investigating the mother-infant interaction and the oxytocin modulation of emotional stimuli in humans. We performed two systematic literature searches: fMRI studies investigating the neurofunctional correlates of the 'maternal brain' by employing mother-infant paradigms; and fMRI studies employing oxytocin during emotional tasks. A unimodal voxel-based meta-analysis was performed on each database, whereas a multimodal voxel-based meta-analytical tool was adopted to assess the hypothesis that the neurofunctional effects of oxytocin are detected in brain areas implicated in the 'maternal brain.' We found greater activation in the bilateral insula extending to the inferior frontal gyrus, basal ganglia and thalamus during mother-infant interaction and greater left insular activation associated with oxytocin administration versus placebo. Left insula extending to basal ganglia and frontotemporal gyri as well as bilateral thalamus and amygdala showed consistent activation across the two paradigms. Right insula also showed activation across the two paradigms, and dorsomedial frontal cortex activation in mothers but deactivation with oxytocin. Significant activation in areas involved in empathy, emotion regulation, motivation, social cognition and theory of mind emerged from our multimodal meta-analysis, supporting the need for further studies directly investigating the neurobiology of oxytocin in the mother-infant relationship. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

Estimation of Temporal Gait Parameters Using a Human Body Electrostatic Sensing-Based Method.

PubMed

Li, Mengxuan; Li, Pengfei; Tian, Shanshan; Tang, Kai; Chen, Xi

2018-05-28

Accurate estimation of gait parameters is essential for obtaining quantitative information on motor deficits in Parkinson's disease and other neurodegenerative diseases, which helps determine disease progression and therapeutic interventions. Due to the demand for high accuracy, unobtrusive measurement methods such as optical motion capture systems, foot pressure plates, and other systems have been commonly used in clinical environments. However, the high cost of existing lab-based methods greatly hinders their wider usage, especially in developing countries. In this study, we present a low-cost, noncontact, and an accurate temporal gait parameters estimation method by sensing and analyzing the electrostatic field generated from human foot stepping. The proposed method achieved an average 97% accuracy on gait phase detection and was further validated by comparison to the foot pressure system in 10 healthy subjects. Two results were compared using the Pearson coefficient r and obtained an excellent consistency ( r = 0.99, p < 0.05). The repeatability of the purposed method was calculated between days by intraclass correlation coefficients (ICC), and showed good test-retest reliability (ICC = 0.87, p < 0.01). The proposed method could be an affordable and accurate tool to measure temporal gait parameters in hospital laboratories and in patients' home environments.

Gait disorder rehabilitation using vision and non-vision based sensors: A systematic review

PubMed Central

Ali, Asraf; Sundaraj, Kenneth; Ahmad, Badlishah; Ahamed, Nizam; Islam, Anamul

2012-01-01

Even though the amount of rehabilitation guidelines has never been greater, uncertainty continues to arise regarding the efficiency and effectiveness of the rehabilitation of gait disorders. This question has been hindered by the lack of information on accurate measurements of gait disorders. Thus, this article reviews the rehabilitation systems for gait disorder using vision and non-vision sensor technologies, as well as the combination of these. All papers published in the English language between 1990 and June, 2012 that had the phrases “gait disorder” “rehabilitation”, “vision sensor”, or “non vision sensor” in the title, abstract, or keywords were identified from the SpringerLink, ELSEVIER, PubMed, and IEEE databases. Some synonyms of these phrases and the logical words “and” “or” and “not” were also used in the article searching procedure. Out of the 91 published articles found, this review identified 84 articles that described the rehabilitation of gait disorders using different types of sensor technologies. This literature set presented strong evidence for the development of rehabilitation systems using a markerless vision-based sensor technology. We therefore believe that the information contained in this review paper will assist the progress of the development of rehabilitation systems for human gait disorders. PMID:22938548

Brain-controlled functional electrical stimulation therapy for gait rehabilitation after stroke: a safety study.

PubMed

McCrimmon, Colin M; King, Christine E; Wang, Po T; Cramer, Steven C; Nenadic, Zoran; Do, An H

2015-07-11

Many stroke survivors have significant long-term gait impairment, often involving foot drop. Current physiotherapies provide limited recovery. Orthoses substitute for ankle strength, but they provide no lasting therapeutic effect. Brain-computer interface (BCI)-controlled functional electrical stimulation (FES) is a novel rehabilitative approach that may generate permanent neurological improvements. This study explores the safety and feasibility of a foot-drop-targeted BCI-FES physiotherapy in chronic stroke survivors. Subjects (n = 9) operated an electroencephalogram-based BCI-FES system for foot dorsiflexion in 12 one-hour sessions over four weeks. Gait speed, dorsiflexion active range of motion (AROM), six-minute walk distance (6MWD), and Fugl-Meyer leg motor (FM-LM) scores were assessed before, during, and after therapy. The primary safety outcome measure was the proportion of subjects that deteriorated in gait speed by ≥0.16 m/s at one week or four weeks post-therapy. The secondary outcome measures were the proportion of subjects that experienced a clinically relevant decrease in dorsiflexion AROM (≥2.5°), 6MWD (≥20 %), and FM-LM score (≥10 %) at either post-therapy assessment. No subjects (0/9) experienced a clinically significant deterioration in gait speed, dorsiflexion AROM, 6MWT distance, or FM-LM score at either post-therapy assessment. Five subjects demonstrated a detectable increase (≥0.06 m/s) in gait speed, three subjects demonstrated a detectable increase (≥2.5°) in dorsiflexion AROM, five subjects demonstrated a detectable increase (≥10 %) in 6MWD, and three subjects demonstrated a detectable increase (≥10 %) in FM-LM. Five of the six subjects that exhibited a detectable increase in either post-therapy gait speed or 6MWD also exhibited significant (p < 0.01 using a Mann-Whitney U test) increases in electroencephalogram event-related synchronization/desynchronization. Additionally, two subjects experienced a clinically

IMU-Based Gait Recognition Using Convolutional Neural Networks and Multi-Sensor Fusion.

PubMed

Dehzangi, Omid; Taherisadr, Mojtaba; ChangalVala, Raghvendar

2017-11-27

The wide spread usage of wearable sensors such as in smart watches has provided continuous access to valuable user generated data such as human motion that could be used to identify an individual based on his/her motion patterns such as, gait. Several methods have been suggested to extract various heuristic and high-level features from gait motion data to identify discriminative gait signatures and distinguish the target individual from others. However, the manual and hand crafted feature extraction is error prone and subjective. Furthermore, the motion data collected from inertial sensors have complex structure and the detachment between manual feature extraction module and the predictive learning models might limit the generalization capabilities. In this paper, we propose a novel approach for human gait identification using time-frequency (TF) expansion of human gait cycles in order to capture joint 2 dimensional (2D) spectral and temporal patterns of gait cycles. Then, we design a deep convolutional neural network (DCNN) learning to extract discriminative features from the 2D expanded gait cycles and jointly optimize the identification model and the spectro-temporal features in a discriminative fashion. We collect raw motion data from five inertial sensors placed at the chest, lower-back, right hand wrist, right knee, and right ankle of each human subject synchronously in order to investigate the impact of sensor location on the gait identification performance. We then present two methods for early (input level) and late (decision score level) multi-sensor fusion to improve the gait identification generalization performance. We specifically propose the minimum error score fusion (MESF) method that discriminatively learns the linear fusion weights of individual DCNN scores at the decision level by minimizing the error rate on the training data in an iterative manner. 10 subjects participated in this study and hence, the problem is a 10-class identification task

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

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.

Reliability and validity of gait analysis by android-based smartphone.

PubMed

Nishiguchi, Shu; Yamada, Minoru; Nagai, Koutatsu; Mori, Shuhei; Kajiwara, Yuu; Sonoda, Takuya; Yoshimura, Kazuya; Yoshitomi, Hiroyuki; Ito, Hiromu; Okamoto, Kazuya; Ito, Tatsuaki; Muto, Shinyo; Ishihara, Tatsuya; Aoyama, Tomoki

2012-05-01

Smartphones are very common devices in daily life that have a built-in tri-axial accelerometer. Similar to previously developed accelerometers, smartphones can be used to assess gait patterns. However, few gait analyses have been performed using smartphones, and their reliability and validity have not been evaluated yet. The purpose of this study was to evaluate the reliability and validity of a smartphone accelerometer. Thirty healthy young adults participated in this study. They walked 20 m at their preferred speeds, and their trunk accelerations were measured using a smartphone and a tri-axial accelerometer that was secured over the L3 spinous process. We developed a gait analysis application and installed it in the smartphone to measure the acceleration. After signal processing, we calculated the gait parameters of each measurement terminal: peak frequency (PF), root mean square (RMS), autocorrelation peak (AC), and coefficient of variance (CV) of the acceleration peak intervals. Remarkable consistency was observed in the test-retest reliability of all the gait parameter results obtained by the smartphone (p<0.001). All the gait parameter results obtained by the smartphone showed statistically significant and considerable correlations with the same parameter results obtained by the tri-axial accelerometer (PF r=0.99, RMS r=0.89, AC r=0.85, CV r=0.82; p<0.01). Our study indicates that the smartphone with gait analysis application used in this study has the capacity to quantify gait parameters with a degree of accuracy that is comparable to that of the tri-axial accelerometer.

A New Classification of Diabetic Gait Pattern Based on Cluster Analysis of Biomechanical Data

PubMed Central

Sawacha, Zimi; Guarneri, Gabriella; Avogaro, Angelo; Cobelli, Claudio

2010-01-01

Background The diabetic foot, one of the most serious complications of diabetes mellitus and a major risk factor for plantar ulceration, is determined mainly by peripheral neuropathy. Neuropathic patients exhibit decreased stability while standing as well as during dynamic conditions. A new methodology for diabetic gait pattern classification based on cluster analysis has been proposed that aims to identify groups of subjects with similar patterns of gait and verify if three-dimensional gait data are able to distinguish diabetic gait patterns from one of the control subjects. Method The gait of 20 nondiabetic individuals and 46 diabetes patients with and without peripheral neuropathy was analyzed [mean age 59.0 (2.9) and 61.1(4.4) years, mean body mass index (BMI) 24.0 (2.8), and 26.3 (2.0)]. K-means cluster analysis was applied to classify the subjects' gait patterns through the analysis of their ground reaction forces, joints and segments (trunk, hip, knee, ankle) angles, and moments. Results Cluster analysis classification led to definition of four well-separated clusters: one aggregating just neuropathic subjects, one aggregating both neuropathics and non-neuropathics, one including only diabetes patients, and one including either controls or diabetic and neuropathic subjects. Conclusions Cluster analysis was useful in grouping subjects with similar gait patterns and provided evidence that there were subgroups that might otherwise not be observed if a group ensemble was presented for any specific variable. In particular, we observed the presence of neuropathic subjects with a gait similar to the controls and diabetes patients with a long disease duration with a gait as altered as the neuropathic one. PMID:20920432

A Neural Network-Based Gait Phase Classification Method Using Sensors Equipped on Lower Limb Exoskeleton Robots

PubMed Central

Jung, Jun-Young; Heo, Wonho; Yang, Hyundae; Park, Hyunsub

2015-01-01

An exact classification of different gait phases is essential to enable the control of exoskeleton robots and detect the intentions of users. We propose a gait phase classification method based on neural networks using sensor signals from lower limb exoskeleton robots. In such robots, foot sensors with force sensing registers are commonly used to classify gait phases. We describe classifiers that use the orientation of each lower limb segment and the angular velocities of the joints to output the current gait phase. Experiments to obtain the input signals and desired outputs for the learning and validation process are conducted, and two neural network methods (a multilayer perceptron and nonlinear autoregressive with external inputs (NARX)) are used to develop an optimal classifier. Offline and online evaluations using four criteria are used to compare the performance of the classifiers. The proposed NARX-based method exhibits sufficiently good performance to replace foot sensors as a means of classifying gait phases. PMID:26528986

A Neural Network-Based Gait Phase Classification Method Using Sensors Equipped on Lower Limb Exoskeleton Robots.

PubMed

Jung, Jun-Young; Heo, Wonho; Yang, Hyundae; Park, Hyunsub

2015-10-30

An exact classification of different gait phases is essential to enable the control of exoskeleton robots and detect the intentions of users. We propose a gait phase classification method based on neural networks using sensor signals from lower limb exoskeleton robots. In such robots, foot sensors with force sensing registers are commonly used to classify gait phases. We describe classifiers that use the orientation of each lower limb segment and the angular velocities of the joints to output the current gait phase. Experiments to obtain the input signals and desired outputs for the learning and validation process are conducted, and two neural network methods (a multilayer perceptron and nonlinear autoregressive with external inputs (NARX)) are used to develop an optimal classifier. Offline and online evaluations using four criteria are used to compare the performance of the classifiers. The proposed NARX-based method exhibits sufficiently good performance to replace foot sensors as a means of classifying gait phases.

Characterization of gait function in patients with postsurgical sagittal (flatback) deformity: a prospective study of 21 patients.

PubMed

Sarwahi, Vishal; Boachie-Adjei, Oheneba; Backus, Sherry I; Taira, Gaku

2002-11-01

This study prospectively analyzed gait in 21 patients with flatback and reviewed radiographs and charts. To analyze the effect of sagittal imbalance on gait and hip and knee joints. Loss of lumbar lordosis causes anterior displacement of the center of gravity, which creates instability and increases the work of gait. Several compensatory changes occur in response. The long-term effect of these changes on extra-axial joints has not been reported, nor have many studies analyzed the gait deviations in patients with flatback. Over time, as patients' ability to compensate is limited, increased gait deviations result. A total of 21 of 44 patients who had gait analysis as part of the preoperative workup were selected based on outlined criteria. Kinetics and kinematics data were analyzed along with radiographic and chart review. Normal healthy individuals served as controls. Gait deviations were present in gait kinetics and kinematics, including decreased stride length and velocity, to almost 60% of controls. Stance duration was prolonged with increased hip and knee flexion during stance. Hip and knee extensor moments were decreased with vertical ground reaction force showing slower rate of loading, reduced peak values, and flattening of normal loading response. Patients with flatback develop several compensatory mechanisms. The goal of the compensation is to maintain an efficient gait and decrease joint damage, but these safeguards fail over time. Flatback not only causes backache, abnormal posture, and abnormal body mechanics but also compromises the stability of gait and taxes the knee and hip joints adversely.

The effect of uphill and downhill walking on gait parameters: A self-paced treadmill study.

PubMed

Kimel-Naor, Shani; Gottlieb, Amihai; Plotnik, Meir

2017-07-26

It has been shown that gait parameters vary systematically with the slope of the surface when walking uphill (UH) or downhill (DH) (Andriacchi et al., 1977; Crowe et al., 1996; Kawamura et al., 1991; Kirtley et al., 1985; McIntosh et al., 2006; Sun et al., 1996). However, gait trials performed on inclined surfaces have been subject to certain technical limitations including using fixed speed treadmills (TMs) or, alternatively, sampling only a few gait cycles on inclined ramps. Further, prior work has not analyzed upper body kinematics. This study aims to investigate effects of slope on gait parameters using a self-paced TM (SPTM) which facilitates more natural walking, including measuring upper body kinematics and gait coordination parameters. Gait of 11 young healthy participants was sampled during walking in steady state speed. Measurements were made at slopes of +10°, 0° and -10°. Force plates and a motion capture system were used to reconstruct twenty spatiotemporal gait parameters. For validation, previously described parameters were compared with the literature, and novel parameters measuring upper body kinematics and bilateral gait coordination were also analyzed. Results showed that most lower and upper body gait parameters were affected by walking slope angle. Specifically, UH walking had a higher impact on gait kinematics than DH walking. However, gait coordination parameters were not affected by walking slope, suggesting that gait asymmetry, left-right coordination and gait variability are robust characteristics of walking. The findings of the study are discussed in reference to a potential combined effect of slope and gait speed. Follow-up studies are needed to explore the relative effects of each of these factors. Copyright © 2017. Published by Elsevier Ltd.

Voxel-based morphometry study of the insular cortex in bipolar depression.

PubMed

Tang, Li-Rong; Liu, Chun-Hong; Jing, Bin; Ma, Xin; Li, Hai-Yun; Zhang, Yu; Li, Feng; Wang, Yu-Ping; Yang, Zhi; Wang, Chuan-Yue

2014-11-30

Bipolar depression (BD) is a common psychiatric illness characterized by deficits in emotional and cognitive processing. Abnormalities in the subregions of the insula are common findings in neuroanatomical studies of patients with bipolar disorder. However, the specific relationships between morphometric changes in specific insular subregions and the pathogenesis of BD are not clear. In this study, structural magnetic resonance imaging (MRI) was used to investigate gray matter volume abnormalities in the insular subregion in 27 patients with BD and in 27 age and sex-matched controls. Using DARTEL (diffeomorphic anatomical registration through exponentiated lie algebra) for voxel-based morphometry (VBM), we examined changes in regional gray matter volumes of the insula in patients with BD. As compared with healthy controls, the BD patients showed decreased gray matter volumes in the right posterior insula and left ventral anterior insula and increased gray matter volumes in the left dorsal anterior insula. Consistent with the emerging theory of insular interference as a contributor to emotional-cognitive dysregulation, the current findings suggest that the insular cortex may be involved in the neural substrates of BD. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Information presentation through a head-worn display (“smart glasses”) has a smaller influence on the temporal structure of gait variability during dual-task gait compared to handheld displays (paper-based system and smartphone)

PubMed Central

Sedighi, Alireza; Ulman, Sophia M.

2018-01-01

The need to complete multiple tasks concurrently is a common occurrence both daily life and in occupational activities, which can often include simultaneous cognitive and physical demands. As one example, there is increasing availability of head-worn display technologies that can be employed when a user is mobile (e.g., while walking). This new method of information presentation may, however, introduce risks of adverse outcomes such as a decrement to gait performance. The goal of this study was thus to quantify the effects of a head-worn display (i.e., smart glasses) on motor variability during gait and to compare these effects with those of other common information displays (i.e., smartphone and paper-based system). Twenty participants completed four walking conditions, as a single task and in three dual-task conditions (three information displays). In the dual-task conditions, the information display was used to present several cognitive tasks. Three different measures were used to quantify variability in gait parameters for each walking condition (using the cycle-to-cycle standard deviation, sample entropy, and the “goal-equivalent manifold” approach). Our results indicated that participants used less adaptable gait strategies in dual-task walking using the paper-based system and smartphone conditions compared with single-task walking. Gait performance, however, was less affected during dual-task walking with the smart glasses. We conclude that the risk of an adverse gait event (e.g., a fall) in head-down walking conditions (i.e., the paper-based system and smartphone conditions) were higher than in single-task walking, and that head-worn displays might help reduce the risk of such events during dual-task gait conditions. PMID:29630614

A proof-of-concept study for measuring gait speed, steadiness, and dynamic balance under various footwear conditions outside of the gait laboratory.

PubMed

Wrobel, James S; Edgar, Sarah; Cozzetto, Dana; Maskill, James; Peterson, Paul; Najafi, Bijan

2010-01-01

This pilot study examined the effect of custom and prefabricated foot orthoses on self-selected walking speed, walking speed variability, and dynamic balance in the mediolateral direction. The gait of four healthy participants was analyzed with a body-worn sensor system across a distance of at least 30 m outside of the gait laboratory. Participants walked at their habitual speed in four conditions: barefoot, regular shoes, prefabricated foot orthoses, and custom foot orthoses. In the custom foot orthoses condition, gait speed was improved on average 13.5% over the barefoot condition and 9.8% over the regular shoe condition. The mediolateral range of motion of center of mass was reduced 55% and 56% compared with the shoes alone and prefabricated foot orthoses conditions, respectively. This may suggest better gait efficiency and lower energy cost with custom foot orthoses. This tendency remained after normalizing center of mass by gait speed, suggesting that irrespective of gait speed, custom foot orthoses improve center of mass motion in the mediolateral direction compared with other footwear conditions. Gait intercycle variability, measured by intercycle coefficient of variation of gait speed, was decreased on average by 25% and 19% compared with the barefoot and shoes-alone conditions, respectively. The decrease in gait unsteadiness after wearing custom foot orthoses may suggest improved proprioception from the increased contact area of custom foot orthoses versus the barefoot condition. These findings may open new avenues for objective assessment of the impact of prescribed footwear on dynamic balance and spatiotemporal parameters of gait and assess gait adaptation after use of custom foot orthoses.

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index.

PubMed

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D K; Leong, John C Y

2009-12-01

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

A gait stability investigation into FES-assisted paraplegic walking based on the walker tipping index

NASA Astrophysics Data System (ADS)

Ming, Dong; Bai, Yanru; Liu, Xiuyun; Qi, Hongzhi; Cheng, Longlong; Wan, Baikun; Hu, Yong; Wong, Yatwa; Luk, Keith D. K.; Leong, John C. Y.

2009-12-01

The gait outcome measures used in clinical trials of paraplegic locomotor training determine the effectiveness of improved walking function assisted by the functional electrical stimulation (FES) system. Focused on kinematic, kinetic or physiological changes of paraplegic patients, traditional methods cannot quantify the walking stability or identify the unstable factors of gait in real time. Up until now, the published studies on dynamic gait stability for the effective use of FES have been limited. In this paper, the walker tipping index (WTI) was used to analyze and process gait stability in FES-assisted paraplegic walking. The main instrument was a specialized walker dynamometer system based on a multi-channel strain-gauge bridge network fixed on the frame of the walker. This system collected force information for the handle reaction vector between the patient's upper extremities and the walker during the walking process; the information was then converted into walker tipping index data, which is an evaluation indicator of the patient's walking stability. To demonstrate the potential usefulness of WTI in gait analysis, a preliminary clinical trial was conducted with seven paraplegic patients who were undergoing FES-assisted walking training and seven normal control subjects. The gait stability levels were quantified for these patients under different stimulation patterns and controls under normal walking with knee-immobilization through WTI analysis. The results showed that the walking stability in the FES-assisted paraplegic group was worse than that in the control subject group, with the primary concern being in the anterior-posterior plane. This new technique is practical for distinguishing useful gait information from the viewpoint of stability, and may be further applied in FES-assisted paraplegic walking rehabilitation.

Voxel-Based Morphometry ALE meta-analysis of Bipolar Disorder

NASA Astrophysics Data System (ADS)

Magana, Omar; Laird, Robert

2012-03-01

A meta-analysis was performed independently to view the changes in gray matter (GM) on patients with Bipolar disorder (BP). The meta-analysis was conducted on a Talairach Space using GingerALE to determine the voxels and their permutation. In order to achieve the data acquisition, published experiments and similar research studies were uploaded onto the online Voxel-Based Morphometry database (VBM). By doing so, coordinates of activation locations were extracted from Bipolar disorder related journals utilizing Sleuth. Once the coordinates of given experiments were selected and imported to GingerALE, a Gaussian was performed on all foci points to create the concentration points of GM on BP patients. The results included volume reductions and variations of GM between Normal Healthy controls and Patients with Bipolar disorder. A significant amount of GM clusters were obtained in Normal Healthy controls over BP patients on the right precentral gyrus, right anterior cingulate, and the left inferior frontal gyrus. In future research, more published journals could be uploaded onto the database and another VBM meta-analysis could be performed including more activation coordinates or a variation of age groups.

Application of neural based estimation algorithm for gait phases of above knee prosthesis.

PubMed

Tileylioğlu, E; Yilmaz, A

2015-01-01

In this study, two gait phase estimation methods which utilize a rule based quantization and an artificial neural network model respectively are developed and applied for the microcontroller based semi-active knee prosthesis in order to respond user demands and adapt environmental conditions. In this context, an experimental environment in which gait data collected synchronously from both inertial and image based measurement systems has been set up. The inertial measurement system that incorporates MEM accelerometers and gyroscopes is used to perform direct motion measurement through the microcontroller, while the image based measurement system is employed for producing the verification data and assessing the success of the prosthesis. Embedded algorithms dynamically normalize the input data prior to gait phase estimation. The real time analyses of two methods revealed that embedded ANN based approach performs slightly better in comparison with the rule based algorithm and has advantage of being easily-scalable, thus able to accommodate additional input parameters considering the microcontroller constraints.

A voxel-based multiscale model to simulate the radiation response of hypoxic tumors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Espinoza, I., E-mail: iespinoza@fis.puc.cl; Peschke, P.; Karger, C. P.

2015-01-15

Purpose: In radiotherapy, it is important to predict the response of tumors to irradiation prior to the treatment. This is especially important for hypoxic tumors, which are known to be highly radioresistant. Mathematical modeling based on the dose distribution, biological parameters, and medical images may help to improve this prediction and to optimize the treatment plan. Methods: A voxel-based multiscale tumor response model for simulating the radiation response of hypoxic tumors was developed. It considers viable and dead tumor cells, capillary and normal cells, as well as the most relevant biological processes such as (i) proliferation of tumor cells, (ii)more » hypoxia-induced angiogenesis, (iii) spatial exchange of cells leading to tumor growth, (iv) oxygen-dependent cell survival after irradiation, (v) resorption of dead cells, and (vi) spatial exchange of cells leading to tumor shrinkage. Oxygenation is described on a microscopic scale using a previously published tumor oxygenation model, which calculates the oxygen distribution for each voxel using the vascular fraction as the most important input parameter. To demonstrate the capabilities of the model, the dependence of the oxygen distribution on tumor growth and radiation-induced shrinkage is investigated. In addition, the impact of three different reoxygenation processes is compared and tumor control probability (TCP) curves for a squamous cells carcinoma of the head and neck (HNSSC) are simulated under normoxic and hypoxic conditions. Results: The model describes the spatiotemporal behavior of the tumor on three different scales: (i) on the macroscopic scale, it describes tumor growth and shrinkage during radiation treatment, (ii) on a mesoscopic scale, it provides the cell density and vascular fraction for each voxel, and (iii) on the microscopic scale, the oxygen distribution may be obtained in terms of oxygen histograms. With increasing tumor size, the simulated tumors develop a hypoxic core

Objective assessment of motor fatigue in multiple sclerosis using kinematic gait analysis: a pilot study

PubMed Central

2011-01-01

Background Fatigue is a frequent and serious symptom in patients with Multiple Sclerosis (MS). However, to date there are only few methods for the objective assessment of fatigue. The aim of this study was to develop a method for the objective assessment of motor fatigue using kinematic gait analysis based on treadmill walking and an infrared-guided system. Patients and methods Fourteen patients with clinically definite MS participated in this study. Fatigue was defined according to the Fatigue Scale for Motor and Cognition (FSMC). Patients underwent a physical exertion test involving walking at their pre-determined patient-specific preferred walking speed until they reached complete exhaustion. Gait was recorded using a video camera, a three line-scanning camera system with 11 infrared sensors. Step length, width and height, maximum circumduction with the right and left leg, maximum knee flexion angle of the right and left leg, and trunk sway were measured and compared using paired t-tests (α = 0.005). In addition, variability in these parameters during one-minute intervals was examined. The fatigue index was defined as the number of significant mean and SD changes from the beginning to the end of the exertion test relative to the total number of gait kinematic parameters. Results Clearly, for some patients the mean gait parameters were more affected than the variability of their movements while other patients had smaller differences in mean gait parameters with greater increases in variability. Finally, for other patients gait changes with physical exertion manifested both in changes in mean gait parameters and in altered variability. The variability and fatigue indices correlated significantly with the motoric but not with the cognitive dimension of the FSMC score (R = -0.602 and R = -0.592, respectively; P < 0.026). Conclusions Changes in gait patterns following a physical exertion test in patients with MS suffering from motor fatigue can be measured

Statistical Parametric Mapping to Identify Differences between Consensus-Based Joint Patterns during Gait in Children with Cerebral Palsy.

PubMed

Nieuwenhuys, Angela; Papageorgiou, Eirini; Desloovere, Kaat; Molenaers, Guy; De Laet, Tinne

2017-01-01

Experts recently identified 49 joint motion patterns in children with cerebral palsy during a Delphi consensus study. Pattern definitions were therefore the result of subjective expert opinion. The present study aims to provide objective, quantitative data supporting the identification of these consensus-based patterns. To do so, statistical parametric mapping was used to compare the mean kinematic waveforms of 154 trials of typically developing children (n = 56) to the mean kinematic waveforms of 1719 trials of children with cerebral palsy (n = 356), which were classified following the classification rules of the Delphi study. Three hypotheses stated that: (a) joint motion patterns with 'no or minor gait deviations' (n = 11 patterns) do not differ significantly from the gait pattern of typically developing children; (b) all other pathological joint motion patterns (n = 38 patterns) differ from typically developing gait and the locations of difference within the gait cycle, highlighted by statistical parametric mapping, concur with the consensus-based classification rules. (c) all joint motion patterns at the level of each joint (n = 49 patterns) differ from each other during at least one phase of the gait cycle. Results showed that: (a) ten patterns with 'no or minor gait deviations' differed somewhat unexpectedly from typically developing gait, but these differences were generally small (≤3°); (b) all other joint motion patterns (n = 38) differed from typically developing gait and the significant locations within the gait cycle that were indicated by the statistical analyses, coincided well with the classification rules; (c) joint motion patterns at the level of each joint significantly differed from each other, apart from two sagittal plane pelvic patterns. In addition to these results, for several joints, statistical analyses indicated other significant areas during the gait cycle that were not included in the pattern definitions of the consensus study

A voxel-based investigation for MRI-only radiotherapy of the brain using ultra short echo times

NASA Astrophysics Data System (ADS)

Edmund, Jens M.; Kjer, Hans M.; Van Leemput, Koen; Hansen, Rasmus H.; Andersen, Jon AL; Andreasen, Daniel

2014-12-01

Radiotherapy (RT) based on magnetic resonance imaging (MRI) as the only modality, so-called MRI-only RT, would remove the systematic registration error between MR and computed tomography (CT), and provide co-registered MRI for assessment of treatment response and adaptive RT. Electron densities, however, need to be assigned to the MRI images for dose calculation and patient setup based on digitally reconstructed radiographs (DRRs). Here, we investigate the geometric and dosimetric performance for a number of popular voxel-based methods to generate a so-called pseudo CT (pCT). Five patients receiving cranial irradiation, each containing a co-registered MRI and CT scan, were included. An ultra short echo time MRI sequence for bone visualization was used. Six methods were investigated for three popular types of voxel-based approaches; (1) threshold-based segmentation, (2) Bayesian segmentation and (3) statistical regression. Each approach contained two methods. Approach 1 used bulk density assignment of MRI voxels into air, soft tissue and bone based on logical masks and the transverse relaxation time T2 of the bone. Approach 2 used similar bulk density assignments with Bayesian statistics including or excluding additional spatial information. Approach 3 used a statistical regression correlating MRI voxels with their corresponding CT voxels. A similar photon and proton treatment plan was generated for a target positioned between the nasal cavity and the brainstem for all patients. The CT agreement with the pCT of each method was quantified and compared with the other methods geometrically and dosimetrically using both a number of reported metrics and introducing some novel metrics. The best geometrical agreement with CT was obtained with the statistical regression methods which performed significantly better than the threshold and Bayesian segmentation methods (excluding spatial information). All methods agreed significantly better with CT than a reference water MRI

Voxel-based lesion mapping of meningioma: a comprehensive lesion location mapping of 260 lesions.

PubMed

Hirayama, Ryuichi; Kinoshita, Manabu; Arita, Hideyuki; Kagawa, Naoki; Kishima, Haruhiko; Hashimoto, Naoya; Fujimoto, Yasunori; Yoshimine, Toshiki

2018-06-01

OBJECTIVE In the present study the authors aimed to determine preferred locations of meningiomas by avoiding descriptive analysis and instead using voxel-based lesion mapping and 3D image-rendering techniques. METHODS Magnetic resonance images obtained in 248 treatment-naïve meningioma patients with 260 lesions were retrospectively and consecutively collected. All images were registered to a 1-mm isotropic, high-resolution, T1-weighted brain atlas provided by the Montreal Neurological Institute (the MNI152), and a lesion frequency map was created, followed by 3D volume rendering to visualize the preferred locations of meningiomas in 3D. RESULTS The 3D lesion frequency map clearly showed that skull base structures such as parasellar, sphenoid wing, and petroclival regions were commonly affected by the tumor. The middle one-third of the superior sagittal sinus was most commonly affected in parasagittal tumors. Substantial lesion accumulation was observed around the leptomeninges covering the central sulcus and the sylvian fissure, with very few lesions observed at the frontal, parietal, and occipital convexities. CONCLUSIONS Using an objective visualization method, meningiomas were shown to be located around the middle third of the superior sagittal sinus, the perisylvian convexity, and the skull base. These observations, which are in line with previous descriptive analyses, justify further use of voxel-based lesion mapping techniques to help understand the biological nature of this disease.

Mobile Phone-Based Measures of Activity, Step Count, and Gait Speed: Results From a Study of Older Ambulatory Adults in a Naturalistic Setting.

PubMed

Rye Hanton, Cassia; Kwon, Yong-Jun; Aung, Thawda; Whittington, Jackie; High, Robin R; Goulding, Evan H; Schenk, A Katrin; Bonasera, Stephen J

2017-10-03

Cellular mobile telephone technology shows much promise for delivering and evaluating healthcare interventions in cost-effective manners with minimal barriers to access. There is little data demonstrating that these devices can accurately measure clinically important aspects of individual functional status in naturalistic environments outside of the laboratory. The objective of this study was to demonstrate that data derived from ubiquitous mobile phone technology, using algorithms developed and previously validated by our lab in a controlled setting, can be employed to continuously and noninvasively measure aspects of participant (subject) health status including step counts, gait speed, and activity level, in a naturalistic community setting. A second objective was to compare our mobile phone-based data against current standard survey-based gait instruments and clinical physical performance measures in order to determine whether they measured similar or independent constructs. A total of 43 ambulatory, independently dwelling older adults were recruited from Nebraska Medicine, including 25 (58%, 25/43) healthy control individuals from our Engage Wellness Center and 18 (42%, 18/43) functionally impaired, cognitively intact individuals (who met at least 3 of 5 criteria for frailty) from our ambulatory Geriatrics Clinic. The following previously-validated surveys were obtained on study day 1: (1) Late Life Function and Disability Instrument (LLFDI); (2) Survey of Activities and Fear of Falling in the Elderly (SAFFE); (3) Patient Reported Outcomes Measurement Information System (PROMIS), short form version 1.0 Physical Function 10a (PROMIS-PF); and (4) PROMIS Global Health, short form version 1.1 (PROMIS-GH). In addition, clinical physical performance measurements of frailty (10 foot Get up and Go, 4 Meter walk, and Figure-of-8 Walk [F8W]) were also obtained. These metrics were compared to our mobile phone-based metrics collected from the participants in the community

Altered Brain Network in Amyotrophic Lateral Sclerosis: A Resting Graph Theory-Based Network Study at Voxel-Wise Level.

PubMed

Zhou, Chaoyang; Hu, Xiaofei; Hu, Jun; Liang, Minglong; Yin, Xuntao; Chen, Lin; Zhang, Jiuquan; Wang, Jian

2016-01-01

Amyotrophic lateral sclerosis (ALS) is a rare degenerative disorder characterized by loss of upper and lower motor neurons. Neuroimaging has provided noticeable evidence that ALS is a complex disease, and shown that anatomical and functional lesions extend beyond precentral cortices and corticospinal tracts, to include the corpus callosum; frontal, sensory, and premotor cortices; thalamus; and midbrain. The aim of this study is to investigate graph theory-based functional network abnormalities at voxel-wise level in ALS patients on a whole brain scale. Forty-three ALS patients and 44 age- and sex-matched healthy volunteers were enrolled. The voxel-wise network degree centrality (DC), a commonly employed graph-based measure of network organization, was used to characterize the alteration of whole brain functional network. Compared with the controls, the ALS patients showed significant increase of DC in the left cerebellum posterior lobes, bilateral cerebellum crus, bilateral occipital poles, right orbital frontal lobe, and bilateral prefrontal lobes; significant decrease of DC in the bilateral primary motor cortex, bilateral sensory motor region, right prefrontal lobe, left bilateral precuneus, bilateral lateral temporal lobes, left cingulate cortex, and bilateral visual processing cortex. The DC's z-scores of right inferior occipital gyrus were significant negative correlated with the ALSFRS-r scores. Our findings confirm that the regions with abnormal network DC in ALS patients were located in multiple brain regions including primary motor, somatosensory and extra-motor areas, supporting the concept that ALS is a multisystem disorder. Specifically, our study found that DC in the visual areas was altered and ALS patients with higher DC in right inferior occipital gyrus have more severity of disease. The result demonstrated that the altered DC value in this region can probably be used to assess severity of ALS.

A systematic review of gait analysis methods based on inertial sensors and adaptive algorithms.

PubMed

Caldas, Rafael; Mundt, Marion; Potthast, Wolfgang; Buarque de Lima Neto, Fernando; Markert, Bernd

2017-09-01

The conventional methods to assess human gait are either expensive or complex to be applied regularly in clinical practice. To reduce the cost and simplify the evaluation, inertial sensors and adaptive algorithms have been utilized, respectively. This paper aims to summarize studies that applied adaptive also called artificial intelligence (AI) algorithms to gait analysis based on inertial sensor data, verifying if they can support the clinical evaluation. Articles were identified through searches of the main databases, which were encompassed from 1968 to October 2016. We have identified 22 studies that met the inclusion criteria. The included papers were analyzed due to their data acquisition and processing methods with specific questionnaires. Concerning the data acquisition, the mean score is 6.1±1.62, what implies that 13 of 22 papers failed to report relevant outcomes. The quality assessment of AI algorithms presents an above-average rating (8.2±1.84). Therefore, AI algorithms seem to be able to support gait analysis based on inertial sensor data. Further research, however, is necessary to enhance and standardize the application in patients, since most of the studies used distinct methods to evaluate healthy subjects. Copyright © 2017 Elsevier B.V. All rights reserved.

One-year persistence of individual gait patterns identified in a follow-up study - A call for individualised diagnose and therapy.

PubMed

Horst, F; Mildner, M; Schöllhorn, W I

2017-10-01

Although a hunch about the individuality of human movements generally exists, differences in gait patterns between individuals are often neglected. To date, only a few studies distinguished individual gait patterns in terms of uniqueness and emphasised the relevance of individualised diagnoses and therapy. However, small sample sizes have been a limitation on identifying subjects based on gait patterns, and little is known about the permanence of subject-specific characteristics over time. The purpose of this study was (1) to prove the uniqueness of individual gait patterns within a larger sample and (2) to prove the long-term permanence of individual gait patterns. A sample of 128 healthy participants each walked a distance of 10m barefoot 10 times. Two force plates recorded the ground reaction forces during a double step at a self-selected walking speed. A subsample of 46 participants repeated this procedure after a period of 7-16 months. The application of support vector machines resulted in classification rates of 99.8% (1278 out of 1280) and 99.4% (914 out of 920) for the initial subject-classification and the subsample follow-up-classification, respectively. The results showed that gait patterns based on time-continuous ground reaction forces were unique to an individual and could be differentiated from those of other individuals. Support vector machines classified gait patterns to the corresponding individual almost error-free. Hence, human gait is not only different between individuals but also exhibits unique individual characteristics that are persistent over years. Our findings provide evidence for the individual nature of human walking and emphasise the need to evaluate individualised clinical approaches for diagnoses and therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Scrunching: a novel escape gait in planarians

NASA Astrophysics Data System (ADS)

Cochet-Escartin, Olivier; Mickolajczyk, Keith J.; Collins, Eva-Maria S.

2015-10-01

The ability to escape a predator or other life-threatening situations is central to animal survival. Different species have evolved unique strategies under anatomical and environmental constraints. In this study, we describe a novel musculature-driven escape gait in planarians, ‘scrunching’, which is quantitatively different from other planarian gaits, such as gliding and peristalsis. We show that scrunching is a conserved gait among different flatworm species, underlying its importance as an escape mechanism. We further demonstrate that it can be induced by a variety of physical stimuli, including amputation, high temperature, electric shock and low pH. We discuss the functional basis for scrunching as the preferential gait when gliding is impaired due to a disruption of mucus production. Finally, we show that the key mechanical features of scrunching are adequately captured by a simple biomechanical model that is solely based on experimental data from traction force microscopy and tissue rheology without fit parameters. Together, our results form a complete description of this novel form of planarian locomotion. Because scrunching has distinct dynamics, this gait can serve as a robust behavioral readout for studies of motor neuron and muscular functions in planarians and in particular the restoration of these functions during regeneration.

Optimality Principles for Model-Based Prediction of Human Gait

PubMed Central

Ackermann, Marko; van den Bogert, Antonie J.

2010-01-01

Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient’s gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like cost functions produced realistic gait, with stance phase knee flexion, as opposed to energy-related cost functions which avoided knee flexion during the stance phase. We conclude that fatigue minimization may be one of the primary optimality principles governing human gait. PMID:20074736

A mechanical energy analysis of gait initiation

NASA Technical Reports Server (NTRS)

Miller, C. A.; Verstraete, M. C.

1999-01-01

The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool to study pathologic gait and to evaluate prosthetic devices. While past studies have quantified mechanical energy of the body during steady-state gait, to date no one has computed the mechanical energy of the body during gait initiation. In this study, gait initiation in seven normal male subjects was studied using a mechanical energy analysis to compute total body energy. The data showed three separate states: quiet standing, gait initiation, and steady-state gait. During gait initiation, the trends in the energy data for the individual segments were similar to those seen during steady-state gait (and in Winter DA, Quanbury AO, Reimer GD. Analysis of instantaneous energy of normal gait. J Biochem 1976;9:253-257), but diminished in amplitude. However, these amplitudes increased to those seen in steady-state during the gait initiation event (GIE), with the greatest increase occurring in the second step due to the push-off of the foundation leg. The baseline level of mechanical energy was due to the potential energy of the individual segments, while the cyclic nature of the data was indicative of the kinetic energy of the particular leg in swing phase during that step. The data presented showed differences in energy trends during gait initiation from those of steady state, thereby demonstrating the importance of this event in the study of locomotion.

Comparative Study of SVM Methods Combined with Voxel Selection for Object Category Classification on fMRI Data

PubMed Central

Song, Sutao; Zhan, Zhichao; Long, Zhiying; Zhang, Jiacai; Yao, Li

2011-01-01

Background Support vector machine (SVM) has been widely used as accurate and reliable method to decipher brain patterns from functional MRI (fMRI) data. Previous studies have not found a clear benefit for non-linear (polynomial kernel) SVM versus linear one. Here, a more effective non-linear SVM using radial basis function (RBF) kernel is compared with linear SVM. Different from traditional studies which focused either merely on the evaluation of different types of SVM or the voxel selection methods, we aimed to investigate the overall performance of linear and RBF SVM for fMRI classification together with voxel selection schemes on classification accuracy and time-consuming. Methodology/Principal Findings Six different voxel selection methods were employed to decide which voxels of fMRI data would be included in SVM classifiers with linear and RBF kernels in classifying 4-category objects. Then the overall performances of voxel selection and classification methods were compared. Results showed that: (1) Voxel selection had an important impact on the classification accuracy of the classifiers: in a relative low dimensional feature space, RBF SVM outperformed linear SVM significantly; in a relative high dimensional space, linear SVM performed better than its counterpart; (2) Considering the classification accuracy and time-consuming holistically, linear SVM with relative more voxels as features and RBF SVM with small set of voxels (after PCA) could achieve the better accuracy and cost shorter time. Conclusions/Significance The present work provides the first empirical result of linear and RBF SVM in classification of fMRI data, combined with voxel selection methods. Based on the findings, if only classification accuracy was concerned, RBF SVM with appropriate small voxels and linear SVM with relative more voxels were two suggested solutions; if users concerned more about the computational time, RBF SVM with relative small set of voxels when part of the principal

Gender may have an influence on the relationship between Functional Movement Screen scores and gait parameters in elite junior athletes - A pilot study.

PubMed

Magyari, N; Szakács, V; Bartha, C; Szilágyi, B; Galamb, K; Magyar, M O; Hortobágyi, T; Kiss, R M; Tihanyi, J; Négyesi, J

2017-09-01

Aims The aim of this study was to examine the effects of gender on the relationship between Functional Movement Screen (FMS) and treadmill-based gait parameters. Methods Twenty elite junior athletes (10 women and 10 men) performed the FMS tests and gait analysis at a fixed speed. Between-gender differences were calculated for the relationship between FMS test scores and gait parameters, such as foot rotation, step length, and length of gait line. Results Gender did not affect the relationship between FMS and treadmill-based gait parameters. The nature of correlations between FMS test scores and gait parameters was different in women and men. Furthermore, different FMS test scores predicted different gait parameters in female and male athletes. FMS asymmetry and movement asymmetries measured by treadmill-based gait parameters did not correlate in either gender. Conclusion There were no interactions between FMS, gait parameters, and gender; however, correlation analyses support the idea that strength and conditioning coaches need to pay attention not only to how to score but also how to correctly use FMS.

Climbing favours the tripod gait over alternative faster insect gaits

NASA Astrophysics Data System (ADS)

Ramdya, Pavan; Thandiackal, Robin; Cherney, Raphael; Asselborn, Thibault; Benton, Richard; Ijspeert, Auke Jan; Floreano, Dario

2017-02-01

To escape danger or catch prey, running vertebrates rely on dynamic gaits with minimal ground contact. By contrast, most insects use a tripod gait that maintains at least three legs on the ground at any given time. One prevailing hypothesis for this difference in fast locomotor strategies is that tripod locomotion allows insects to rapidly navigate three-dimensional terrain. To test this, we computationally discovered fast locomotor gaits for a model based on Drosophila melanogaster. Indeed, the tripod gait emerges to the exclusion of many other possible gaits when optimizing fast upward climbing with leg adhesion. By contrast, novel two-legged bipod gaits are fastest on flat terrain without adhesion in the model and in a hexapod robot. Intriguingly, when adhesive leg structures in real Drosophila are covered, animals exhibit atypical bipod-like leg coordination. We propose that the requirement to climb vertical terrain may drive the prevalence of the tripod gait over faster alternative gaits with minimal ground contact.

Climbing favours the tripod gait over alternative faster insect gaits

PubMed Central

Ramdya, Pavan; Thandiackal, Robin; Cherney, Raphael; Asselborn, Thibault; Benton, Richard; Ijspeert, Auke Jan; Floreano, Dario

2017-01-01

To escape danger or catch prey, running vertebrates rely on dynamic gaits with minimal ground contact. By contrast, most insects use a tripod gait that maintains at least three legs on the ground at any given time. One prevailing hypothesis for this difference in fast locomotor strategies is that tripod locomotion allows insects to rapidly navigate three-dimensional terrain. To test this, we computationally discovered fast locomotor gaits for a model based on Drosophila melanogaster. Indeed, the tripod gait emerges to the exclusion of many other possible gaits when optimizing fast upward climbing with leg adhesion. By contrast, novel two-legged bipod gaits are fastest on flat terrain without adhesion in the model and in a hexapod robot. Intriguingly, when adhesive leg structures in real Drosophila are covered, animals exhibit atypical bipod-like leg coordination. We propose that the requirement to climb vertical terrain may drive the prevalence of the tripod gait over faster alternative gaits with minimal ground contact. PMID:28211509

Positive outcomes following gait therapy intervention for hip osteoarthritis: A longitudinal study.

PubMed

Solomonow-Avnon, Deborah; Herman, Amir; Levin, Daniel; Rozen, Nimrod; Peled, Eli; Wolf, Alon

2017-10-01

Footwear-generated biomechanical manipulation of lower-limb joints was shown to beneficially impact gait and quality of life in knee osteoarthritis patients, but has not been tested in hip osteoarthritis patients. We examined a customized gait treatment program using a biomechanical device shown in previous investigations to be capable of manipulating hip biomechanics via foot center of pressure (COP) modulation. The objective of this study was to assess the treatment program for hip osteoarthritis patients, enrolled in a 1-year prospective investigation, by means of objective gait and spatiotemporal parameters, and subjective quality of life measures. Gait analysis and completion of questionnaires were performed at the start of the treatment (baseline), and after 3, 6, and 12 months. Outcome parameters were evaluated over time using linear mixed effects models, and association between improvement in quality of life measures and change in objective outcomes was tested using mixed effect linear regression models. Quality of life measures improved compared to baseline, accompanied by increased gait speed and cadence. Sagittal-plane hip joint kinetics, kinematics, and spatiotemporal parameters changed throughout the study compared to baseline, in a manner suggesting improvement of gait. The most substantial improvement occurred within 3 months after treatment initiation, after which improvement approximately plateaued, but was sustained at 12 months. Speed and cadence, as well as several sagittal-plane gait parameters, were significant predictors of improvement in quality of life. Evidence suggests that a biomechanical gait therapy program improves subjective and objective outcomes measures and is a valid treatment option for hip osteoarthritis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2222-2232, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Combining Gait Speed and Recall Memory to Predict Survival in Late Life: Population-Based Study

PubMed Central

Marengoni, Alessandra; Bandinelli, Stefania; Maietti, Elisa; Guralnik, Jack; Zuliani, Giovanni; Ferrucci, Luigi; Volpato, Stefano

2017-01-01

OBJECTIVES To evaluate the relationship between gait speed, recall memory, and mortality. DESIGN A cohort study (last follow-up December 2009). SETTING Tuscany, Italy. PARTICIPANTS Individual data from 1,014 community-dwelling older adults aged 60 years or older with baseline gait speed and recall memory measurements and follow-up for a median time of 9.10 (IQR 7.1;9.3) years. Participants were a mean (SD) age of 73.9 (7.3) years, and 55.8% women. Participants walking faster than 0.8 m/s were defined as fast walkers; good recall memory was defined as a score of 2 or 3 in the 3-word delayed recall section of the Mini-Mental State Examination. MEASUREMENTS All-cause mortality. RESULTS There were 302 deaths and the overall 100 person-year death rate was 3.77 (95% CI: 3.37–4.22). Both low gait speed and poor recall memory were associated with mortality when analysed separately (HR = 2.47; 95% CI: 1.87–3.27 and HR = 1.47; 95% CI: 1.16–1.87, respectively). When we grouped participants according to both recall and gait speed, death rates (100 person-years) progressively increased from those with both good gait speed and memory (2.0; 95% CI: 1.6–2.5), to those with fast walk but poor memory (3.4; 95% CI: 2.8–4.2), to those with slow walk and good memory (8.8; 95% CI: 6.4–12.1), to those with both slow walk and poor memory (13.0; 95% CI: 10.6–16.1). In multivariate analysis, poor memory significantly increases mortality risk among persons with fast gait speed (HR = 1.40; 95% CI: 1.04–1.89). CONCLUSION In older persons, gait speed and recall memory are independent predictors of expected survival. Information on memory function might better stratify mortality risk among persons with fast gait speed. PMID:28029688

Combining Gait Speed and Recall Memory to Predict Survival in Late Life: Population-Based Study.

PubMed

Marengoni, Alessandra; Bandinelli, Stefania; Maietti, Elisa; Guralnik, Jack; Zuliani, Giovanni; Ferrucci, Luigi; Volpato, Stefano

2017-03-01

To evaluate the relationship between gait speed, recall memory, and mortality. A cohort study (last follow-up December 2009). Tuscany, Italy. Individual data from 1,014 community-dwelling older adults aged 60 years or older with baseline gait speed and recall memory measurements and follow-up for a median time of 9.10 (IQR 7.1;9.3) years. Participants were a mean (SD) age of 73.9 (7.3) years, and 55.8% women. Participants walking faster than 0.8 m/s were defined as fast walkers; good recall memory was defined as a score of 2 or 3 in the 3-word delayed recall section of the Mini-Mental State Examination. All-cause mortality. There were 302 deaths and the overall 100 person-year death rate was 3.77 (95% CI: 3.37-4.22). Both low gait speed and poor recall memory were associated with mortality when analysed separately (HR = 2.47; 95% CI: 1.87-3.27 and HR = 1.47; 95% CI: 1.16-1.87, respectively). When we grouped participants according to both recall and gait speed, death rates (100 person-years) progressively increased from those with both good gait speed and memory (2.0; 95% CI: 1.6-2.5), to those with fast walk but poor memory (3.4; 95% CI: 2.8-4.2), to those with slow walk and good memory (8.8; 95% CI: 6.4-12.1), to those with both slow walk and poor memory (13.0; 95% CI: 10.6-16.1). In multivariate analysis, poor memory significantly increases mortality risk among persons with fast gait speed (HR = 1.40; 95% CI: 1.04-1.89). In older persons, gait speed and recall memory are independent predictors of expected survival. Information on memory function might better stratify mortality risk among persons with fast gait speed. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

Physiotherapy, based on the Bobath concept, may influence the gait pattern in persons with limb-girdle muscle dystrophy: a multiple case series study.

PubMed

Oygard, Kjellaug; Haestad, Helge; Jørgensen, Lone

2011-03-01

 There are few studies on possible effects of physiotherapy for adults with muscular dystrophy. The aim of this study was to examine if treatment based on the Bobath concept may influence specific gait parameters in some of these patients.   A single-subject experimental design with A-B-A-A phases was used, and four patients, three with limb-girdle muscular dystrophy (LGMD) and one with fascioscapulohumeral muscular dystrophy (FSHD), were included. The patients had 1 hour of individually tailored physiotherapy at each working day for a period of 3 weeks. Step length, step width and gait velocity were measured during the A-B-A-A phases by use of an electronic walkway. Walking distance and endurance were measured by use of the '6 minute walk test'.  . The three LGMD patients, who initially walked with a wide base of support, had a narrower, velocity-adjusted step width after treatment, accompanied with the same or even longer step length. These changes lasted throughout follow-up. Moreover, two of the patients were able to walk a longer distance within 6 minutes after the treatment period. The fourth patient (with FSHD) had a normal step width at baseline, which did not change during the study.   The results indicate that physiotherapy treatment based on the Bobath concept may influence the gait pattern in patients with LGMD. However, in order to evaluate the effectiveness of physiotherapy to patients with muscular dystrophies, we call for larger studies and controlled trials. Copyright © 2010 John Wiley & Sons, Ltd.

A non-voxel-based broad-beam (NVBB) framework for IMRT treatment planning.

PubMed

Lu, Weiguo

2010-12-07

We present a novel framework that enables very large scale intensity-modulated radiation therapy (IMRT) planning in limited computation resources with improvements in cost, plan quality and planning throughput. Current IMRT optimization uses a voxel-based beamlet superposition (VBS) framework that requires pre-calculation and storage of a large amount of beamlet data, resulting in large temporal and spatial complexity. We developed a non-voxel-based broad-beam (NVBB) framework for IMRT capable of direct treatment parameter optimization (DTPO). In this framework, both objective function and derivative are evaluated based on the continuous viewpoint, abandoning 'voxel' and 'beamlet' representations. Thus pre-calculation and storage of beamlets are no longer needed. The NVBB framework has linear complexities (O(N(3))) in both space and time. The low memory, full computation and data parallelization nature of the framework render its efficient implementation on the graphic processing unit (GPU). We implemented the NVBB framework and incorporated it with the TomoTherapy treatment planning system (TPS). The new TPS runs on a single workstation with one GPU card (NVBB-GPU). Extensive verification/validation tests were performed in house and via third parties. Benchmarks on dose accuracy, plan quality and throughput were compared with the commercial TomoTherapy TPS that is based on the VBS framework and uses a computer cluster with 14 nodes (VBS-cluster). For all tests, the dose accuracy of these two TPSs is comparable (within 1%). Plan qualities were comparable with no clinically significant difference for most cases except that superior target uniformity was seen in the NVBB-GPU for some cases. However, the planning time using the NVBB-GPU was reduced many folds over the VBS-cluster. In conclusion, we developed a novel NVBB framework for IMRT optimization. The continuous viewpoint and DTPO nature of the algorithm eliminate the need for beamlets and lead to better plan

a Super Voxel-Based Riemannian Graph for Multi Scale Segmentation of LIDAR Point Clouds

NASA Astrophysics Data System (ADS)

Li, Minglei

2018-04-01

Automatically segmenting LiDAR points into respective independent partitions has become a topic of great importance in photogrammetry, remote sensing and computer vision. In this paper, we cast the problem of point cloud segmentation as a graph optimization problem by constructing a Riemannian graph. The scale space of the observed scene is explored by an octree-based over-segmentation with different depths. The over-segmentation produces many super voxels which restrict the structure of the scene and will be used as nodes of the graph. The Kruskal coordinates are used to compute edge weights that are proportional to the geodesic distance between nodes. Then we compute the edge-weight matrix in which the elements reflect the sectional curvatures associated with the geodesic paths between super voxel nodes on the scene surface. The final segmentation results are generated by clustering similar super voxels and cutting off the weak edges in the graph. The performance of this method was evaluated on LiDAR point clouds for both indoor and outdoor scenes. Additionally, extensive comparisons to state of the art techniques show that our algorithm outperforms on many metrics.

Instrumented gait analysis: a measure of gait improvement by a wheeled walker in hospitalized geriatric patients.

PubMed

Schülein, Samuel; Barth, Jens; Rampp, Alexander; Rupprecht, Roland; Eskofier, Björn M; Winkler, Jürgen; Gaßmann, Karl-Günter; Klucken, Jochen

2017-02-27

In an increasing aging society, reduced mobility is one of the most important factors limiting activities of daily living and overall quality of life. The ability to walk independently contributes to the mobility, but is increasingly restricted by numerous diseases that impair gait and balance. The aim of this cross-sectional observation study was to examine whether spatio-temporal gait parameters derived from mobile instrumented gait analysis can be used to measure the gait stabilizing effects of a wheeled walker (WW) and whether these gait parameters may serve as surrogate marker in hospitalized patients with multifactorial gait and balance impairment. One hundred six patients (ages 68-95) wearing inertial sensor equipped shoes passed an instrumented walkway with and without gait support from a WW. The walkway assessed the risk of falling associated gait parameters velocity, swing time, stride length, stride time- and double support time variability. Inertial sensor-equipped shoes measured heel strike and toe off angles, and foot clearance. The use of a WW improved the risk of spatio-temporal parameters velocity, swing time, stride length and the sagittal plane associated parameters heel strike and toe off angles in all patients. First-time users (FTUs) showed similar gait parameter improvement patterns as frequent WW users (FUs). However, FUs with higher levels of gait impairment improved more in velocity, stride length and toe off angle compared to the FTUs. The impact of a WW can be quantified objectively by instrumented gait assessment. Thus, objective gait parameters may serve as surrogate markers for the use of walking aids in patients with gait and balance impairments.

Spatiotemporal Gait Characteristics Associated with Cognitive Impairment: A Multicenter Cross-Sectional Study, the Intercontinental "Gait, cOgnitiOn & Decline" Initiative.

PubMed

Beauchet, Olivier; Blumen, Helena M; Callisaya, Michele L; De Cock, Anne-Marie; Kressig, Reto W; Srikanth, Velandai; Steinmetz, Jean-Paul; Verghese, Joe; Allali, Gilles

2018-01-23

The study aims to determine the spatiotemporal gait parameters and/or their combination(s) that best differentiate between cognitively healthy individuals (CHI), patients with mild cognitive impairment (MCI) and those with mild and moderate dementia, regardless of the etiology of cognitive impairment. A total of 2099 participants (1015 CHI, 478 patients with MCI, 331 patients with mild dementia and 275 with moderate dementia) were selected from the intercontinental "Gait, cOgnitiOn & Decline" (GOOD) initiative, which merged different databases from seven cross-sectional studies. Mean values and coefficients of variation (CoV) of spatiotemporal gait parameters were recorded during usual walking with the GAITRite® system. The severity of cognitive impairment was associated with worse performance on all gait parameters. Stride velocity had the strongest association with cognitive impairment, regardless of cognitive status. High mean value and CoV of stride length characterized moderate dementia, whereas increased CoV of stride time was specific to MCI status. The findings support the existence of specific cognitive impairment-related gait disturbances with differences related to stages of cognitive impairment, which may be used to screen individuals with cognitive impairment. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Gait rehabilitation machines based on programmable footplates.

PubMed

Schmidt, Henning; Werner, Cordula; Bernhardt, Rolf; Hesse, Stefan; Krüger, Jörg

2007-02-09

Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing. With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator) or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I). For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS) revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations. Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles of motor relearning promoting a task-specific repetitive

Gait rehabilitation machines based on programmable footplates

PubMed Central

Schmidt, Henning; Werner, Cordula; Bernhardt, Rolf; Hesse, Stefan; Krüger, Jörg

2007-01-01

Background Gait restoration is an integral part of rehabilitation of brain lesioned patients. Modern concepts favour a task-specific repetitive approach, i.e. who wants to regain walking has to walk, while tone-inhibiting and gait preparatory manoeuvres had dominated therapy before. Following the first mobilization out of the bed, the wheelchair-bound patient should have the possibility to practise complex gait cycles as soon as possible. Steps in this direction were treadmill training with partial body weight support and most recently gait machines enabling the repetitive training of even surface gait and even of stair climbing. Results With treadmill training harness-secured and partially relieved wheelchair-mobilised patients could practise up to 1000 steps per session for the first time. Controlled trials in stroke and SCI patients, however, failed to show a superior result when compared to walking exercise on the floor. Most likely explanation was the effort for the therapists, e.g. manually setting the paretic limbs during the swing phase resulting in a too little gait intensity. The next steps were gait machines, either consisting of a powered exoskeleton and a treadmill (Lokomat, AutoAmbulator) or an electromechanical solution with the harness secured patient placed on movable foot plates (Gait Trainer GT I). For the latter, a large multi-centre trial with 155 non-ambulatory stroke patients (DEGAS) revealed a superior gait ability and competence in basic activities of living in the experimental group. The HapticWalker continued the end effector concept of movable foot plates, now fully programmable and equipped with 6 DOF force sensors. This device for the first time enables training of arbitrary walking situations, hence not only the simulation of floor walking but also for example of stair climbing and perturbations. Conclusion Locomotor therapy is a fascinating new tool in rehabilitation, which is in line with modern principles of motor relearning

Quantification and recognition of parkinsonian gait from monocular video imaging using kernel-based principal component analysis

PubMed Central

2011-01-01

Background The computer-aided identification of specific gait patterns is an important issue in the assessment of Parkinson's disease (PD). In this study, a computer vision-based gait analysis approach is developed to assist the clinical assessments of PD with kernel-based principal component analysis (KPCA). Method Twelve PD patients and twelve healthy adults with no neurological history or motor disorders within the past six months were recruited and separated according to their "Non-PD", "Drug-On", and "Drug-Off" states. The participants were asked to wear light-colored clothing and perform three walking trials through a corridor decorated with a navy curtain at their natural pace. The participants' gait performance during the steady-state walking period was captured by a digital camera for gait analysis. The collected walking image frames were then transformed into binary silhouettes for noise reduction and compression. Using the developed KPCA-based method, the features within the binary silhouettes can be extracted to quantitatively determine the gait cycle time, stride length, walking velocity, and cadence. Results and Discussion The KPCA-based method uses a feature-extraction approach, which was verified to be more effective than traditional image area and principal component analysis (PCA) approaches in classifying "Non-PD" controls and "Drug-Off/On" PD patients. Encouragingly, this method has a high accuracy rate, 80.51%, for recognizing different gaits. Quantitative gait parameters are obtained, and the power spectrums of the patients' gaits are analyzed. We show that that the slow and irregular actions of PD patients during walking tend to transfer some of the power from the main lobe frequency to a lower frequency band. Our results indicate the feasibility of using gait performance to evaluate the motor function of patients with PD. Conclusion This KPCA-based method requires only a digital camera and a decorated corridor setup. The ease of use and

Wavelet-based characterization of gait signal for neurological abnormalities.

PubMed

Baratin, E; Sugavaneswaran, L; Umapathy, K; Ioana, C; Krishnan, S

2015-02-01

Studies conducted by the World Health Organization (WHO) indicate that over one billion suffer from neurological disorders worldwide, and lack of efficient diagnosis procedures affects their therapeutic interventions. Characterizing certain pathologies of motor control for facilitating their diagnosis can be useful in quantitatively monitoring disease progression and efficient treatment planning. As a suitable directive, we introduce a wavelet-based scheme for effective characterization of gait associated with certain neurological disorders. In addition, since the data were recorded from a dynamic process, this work also investigates the need for gait signal re-sampling prior to identification of signal markers in the presence of pathologies. To benefit automated discrimination of gait data, certain characteristic features are extracted from the wavelet-transformed signals. The performance of the proposed approach was evaluated using a database consisting of 15 Parkinson's disease (PD), 20 Huntington's disease (HD), 13 Amyotrophic lateral sclerosis (ALS) and 16 healthy control subjects, and an average classification accuracy of 85% is achieved using an unbiased cross-validation strategy. The obtained results demonstrate the potential of the proposed methodology for computer-aided diagnosis and automatic characterization of certain neurological disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

Cerebral gray matter volume variation in female-to-male transsexuals: a voxel-based morphometric study.

PubMed

Kim, Tae-Hoon; Kim, Seok-Kwun; Jeong, Gwang-Woo

2015-12-16

Several studies seem to support the hypothesis that brain anatomy is associated with transsexualism. However, these studies were still limited because few neuroanatomical findings have been obtained from female-to-male (FtM) transsexuals. This study compared the cerebral regional volumes of gray matter (GM) between FtM transsexuals and female controls using a voxel-based morphometry. Twelve FtM transsexuals who had undergone sex-reassignment surgery and 15 female controls participated in this study. Both groups were age matched and right-handed, with no history of neurological illness. Fifteen female controls were recruited to determine whether GM volumes in FtM transsexuals more closely resembled individuals who shared their biological sex. MRI data were processed using SPM 8 with the diffeomorphic anatomical registration through exponentiated Lie algebra (DARTEL). FtM transsexuals showed significantly larger volumes of the thalamus, hypothalamus, midbrain, gyrus rectus, head of caudate nucleus, precentral gyrus, and subcallosal area compared with the female controls. However, the female controls showed a significantly larger volume in the superior temporal gyrus including Heschl's gyrus and Rolandic operculum. These findings confirm that the volume difference in brain substructures in FtM transsexuals is likely to be associated with transsexualism and that transsexualism is probably associated with distinct cerebral structures, determining gender identity.

Statistical Parametric Mapping to Identify Differences between Consensus-Based Joint Patterns during Gait in Children with Cerebral Palsy

PubMed Central

Papageorgiou, Eirini; Desloovere, Kaat; Molenaers, Guy; De Laet, Tinne

2017-01-01

Experts recently identified 49 joint motion patterns in children with cerebral palsy during a Delphi consensus study. Pattern definitions were therefore the result of subjective expert opinion. The present study aims to provide objective, quantitative data supporting the identification of these consensus-based patterns. To do so, statistical parametric mapping was used to compare the mean kinematic waveforms of 154 trials of typically developing children (n = 56) to the mean kinematic waveforms of 1719 trials of children with cerebral palsy (n = 356), which were classified following the classification rules of the Delphi study. Three hypotheses stated that: (a) joint motion patterns with ‘no or minor gait deviations’ (n = 11 patterns) do not differ significantly from the gait pattern of typically developing children; (b) all other pathological joint motion patterns (n = 38 patterns) differ from typically developing gait and the locations of difference within the gait cycle, highlighted by statistical parametric mapping, concur with the consensus-based classification rules. (c) all joint motion patterns at the level of each joint (n = 49 patterns) differ from each other during at least one phase of the gait cycle. Results showed that: (a) ten patterns with ‘no or minor gait deviations’ differed somewhat unexpectedly from typically developing gait, but these differences were generally small (≤3°); (b) all other joint motion patterns (n = 38) differed from typically developing gait and the significant locations within the gait cycle that were indicated by the statistical analyses, coincided well with the classification rules; (c) joint motion patterns at the level of each joint significantly differed from each other, apart from two sagittal plane pelvic patterns. In addition to these results, for several joints, statistical analyses indicated other significant areas during the gait cycle that were not included in the pattern definitions of the consensus

Gait-force model and inertial measurement unit-based measurements: A new approach for gait analysis and balance monitoring.

PubMed

Li, Xinan; Xu, Hongyuan; Cheung, Jeffrey T

2016-12-01

This work describes a new approach for gait analysis and balance measurement. It uses an inertial measurement unit (IMU) that can either be embedded inside a dynamically unstable platform for balance measurement or mounted on the lower back of a human participant for gait analysis. The acceleration data along three Cartesian coordinates is analyzed by the gait-force model to extract bio-mechanics information in both the dynamic state as in the gait analyzer and the steady state as in the balance scale. For the gait analyzer, the simple, noninvasive and versatile approach makes it appealing to a broad range of applications in clinical diagnosis, rehabilitation monitoring, athletic training, sport-apparel design, and many other areas. For the balance scale, it provides a portable platform to measure the postural deviation and the balance index under visual or vestibular sensory input conditions. Despite its simple construction and operation, excellent agreement has been demonstrated between its performance and the high-cost commercial balance unit over a wide dynamic range. The portable balance scale is an ideal tool for routine monitoring of balance index, fall-risk assessment, and other balance-related health issues for both clinical and household use.

A Portable Gait Asymmetry Rehabilitation System for Individuals with Stroke Using a Vibrotactile Feedback.

PubMed

Afzal, Muhammad Raheel; Oh, Min-Kyun; Lee, Chang-Hee; Park, Young Sook; Yoon, Jungwon

2015-01-01

Gait asymmetry caused by hemiparesis results in reduced gait efficiency and reduced activity levels. In this paper, a portable rehabilitation device is proposed that can serve as a tool in diagnosing gait abnormalities in individuals with stroke and has the capability of providing vibration feedback to help compensate for the asymmetric gait. Force-sensitive resistor (FSR) based insoles are used to detect ground contact and estimate stance time. A controller (Arduino) provides different vibration feedback based on the gait phase measurement. It also allows wireless interaction with a personal computer (PC) workstation using the XBee transceiver module, featuring data logging capabilities for subsequent analysis. Walking trials conducted with healthy young subjects allowed us to observe that the system can influence abnormality in the gait. The results of trials showed that a vibration cue based on temporal information was more effective than intensity information. With clinical experiments conducted for individuals with stroke, significant improvement in gait symmetry was observed with minimal disturbance caused to the balance and gait speed as an effect of the biofeedback. Future studies of the long-term rehabilitation effects of the proposed system and further improvements to the system will result in an inexpensive, easy-to-use, and effective rehabilitation device.

A Portable Gait Asymmetry Rehabilitation System for Individuals with Stroke Using a Vibrotactile Feedback

PubMed Central

Afzal, Muhammad Raheel; Oh, Min-Kyun; Lee, Chang-Hee; Park, Young Sook; Yoon, Jungwon

2015-01-01

Gait asymmetry caused by hemiparesis results in reduced gait efficiency and reduced activity levels. In this paper, a portable rehabilitation device is proposed that can serve as a tool in diagnosing gait abnormalities in individuals with stroke and has the capability of providing vibration feedback to help compensate for the asymmetric gait. Force-sensitive resistor (FSR) based insoles are used to detect ground contact and estimate stance time. A controller (Arduino) provides different vibration feedback based on the gait phase measurement. It also allows wireless interaction with a personal computer (PC) workstation using the XBee transceiver module, featuring data logging capabilities for subsequent analysis. Walking trials conducted with healthy young subjects allowed us to observe that the system can influence abnormality in the gait. The results of trials showed that a vibration cue based on temporal information was more effective than intensity information. With clinical experiments conducted for individuals with stroke, significant improvement in gait symmetry was observed with minimal disturbance caused to the balance and gait speed as an effect of the biofeedback. Future studies of the long-term rehabilitation effects of the proposed system and further improvements to the system will result in an inexpensive, easy-to-use, and effective rehabilitation device. PMID:26161398

Grey matter atrophy in mild cognitive impairment / early Alzheimer disease associated with delusions: a voxel-based morphometry study.

PubMed

Ting, Windsor Kwan-Chun; Fischer, Corinne E; Millikin, Colleen P; Ismail, Zahinoor; Chow, Tiffany W; Schweizer, Tom A

2015-01-01

Grey matter atrophy in the right hemisphere has been shown to be more severe in dementia patients with delusions, suggesting a neuroanatomical localization that may be pertinent to impending neurodegeneration. Delusional symptoms may arise when atrophy in these areas reduces the regulatory functions of the right hemisphere, in tandem with asymmetric neuropathology in the left hemisphere. We hypothesized that delusional patients with either amnestic mild cognitive impairment (MCI) or early Alzheimer Disease (AD) would experience more pronounced grey matter atrophy in the right frontal lobe compared with matched patients without delusions. We used neuroimaging and clinical data obtained from the Alzheimer's Disease Neuroimaging Initiative. A comparison group of twenty-nine nondelusional MCI/early AD participants were compared with twenty-nine delusional participants using voxel-based morphometry, matched at baseline by age, sex, education, and Mini-Mental State Exam score. All included participants were diagnosed with amnestic MCI at study baseline. Fifteen voxel clusters of decreased grey matter in participants with delusions were detected. Prominent grey matter decrease was observed in the right precentral gyrus, right inferior frontal gyrus, right insula, and left middle occipital gyrus, areas that may be involved in control of thought and emotions. Greater right fronto-temporal grey matter atrophy was observed in MCI or early AD participants with delusions compared to matched patients without delusions. Consistent with our predictions, asymmetric grey matter atrophy in the right hemisphere may contribute to development of delusions through loss of executive inhibition.

Validation of voxel-based morphometry (VBM) based on MRI

NASA Astrophysics Data System (ADS)

Yang, Xueyu; Chen, Kewei; Guo, Xiaojuan; Yao, Li

2007-03-01

Voxel-based morphometry (VBM) is an automated and objective image analysis technique for detecting differences in regional concentration or volume of brain tissue composition based on structural magnetic resonance (MR) images. VBM has been used widely to evaluate brain morphometric differences between different populations, but there isn't an evaluation system for its validation until now. In this study, a quantitative and objective evaluation system was established in order to assess VBM performance. We recruited twenty normal volunteers (10 males and 10 females, age range 20-26 years, mean age 22.6 years). Firstly, several focal lesions (hippocampus, frontal lobe, anterior cingulate, back of hippocampus, back of anterior cingulate) were simulated in selected brain regions using real MRI data. Secondly, optimized VBM was performed to detect structural differences between groups. Thirdly, one-way ANOVA and post-hoc test were used to assess the accuracy and sensitivity of VBM analysis. The results revealed that VBM was a good detective tool in majority of brain regions, even in controversial brain region such as hippocampus in VBM study. Generally speaking, much more severity of focal lesion was, better VBM performance was. However size of focal lesion had little effects on VBM analysis.

Cross-sectional and longitudinal study of the impact of posterior meniscus horn lesions on adjacent cartilage composition, patient-reported outcomes and gait biomechanics in subjects without radiographic osteoarthritis.

PubMed

Russell, C; Pedoia, V; Souza, R B; Majumdar, S

2017-05-01

The aim of this study was to assess cross-sectional and longitudinal effects of meniscal lesions on adjacent cartilage T 1ρ and T 2 relaxation times, patient-reported outcomes and gait biomechanics. Thirty patients with no cartilage morphological defects reported by Whole Organ MRI Score (WORMS) magnetic resonance imaging (MRI) grading and no radiographic osteoarthritis (OA) (Kellgren--Lawrence (KL) ≤ 1) were selected, 15 with posterior meniscus horn lesions and 15 matched controls without meniscal lesions. All were imaged on a 3T MR scanner for three consecutive years, except those who dropped from the study. Sagittal and frontal plane kinematic gait data were acquired at baseline. The Knee Injury and Osteoarthritis Outcome Score (KOOS) survey was taken each time. All images were automatically segmented and registered to an atlas for voxel-by-voxel cross-sectional and longitudinal analyses. Relaxation time comparisons between groups showed elevated T 1ρ of the lateral tibia (LP) and elevated T 2 of the medial tibia (MT) and LT at 1 and 2 years in the lesion group. Longitudinal comparisons within each group revealed greater relaxation time elevations over one and 2 years in the group with lesions. KOOS Quality of Life (QOL) was significantly different between the groups at all time points (P < 0.05), as were other KOOS subcategories. No significant differences in the frontal or sagittal biomechanics were observed between the groups at baseline. Individuals with healthy cartilage and posterior meniscal horn lesions have increased relaxation times when compared to matched controls, increased relaxation time changes over 2 years, and consistently report a lower KOOS QOL, yet show no difference in gait biomechanics. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Early Gray-Matter and White-Matter Concentration in Infancy Predict Later Language Skills: A Whole Brain Voxel-Based Morphometry Study

ERIC Educational Resources Information Center

Can, Dilara Deniz; Richards, Todd; Kuhl, Patricia K.

2013-01-01

Magnetic Resonance Imaging (MRI) brain scans were obtained from 19 infants at 7 months. Expressive and receptive language performance was assessed at 12 months. Voxel-based morphometry (VBM) identified brain regions where gray-matter and white-matter concentrations at 7 months correlated significantly with children's language scores at 12 months.…

Evidence-based design and development of a VR-based treadmill system for gait research and rehabilitation of patients with Parkinson's disease.

PubMed

Pérez-Sanpablo, Alberto Isaac; González-Mendoza, Arturo; Quiñones-Uriostegui, Ivett; Rodríguez-Reyes, Gerardo; Núñez-Carrera, Lidia; Hernández-Arenas, Claudia; Boll-Woehrlen, Marie Catherine; Alessi Montero, Aldo

2014-07-01

Virtual reality (VR) in neurorehabilitation allows to reduce patient's risk and allows him to learn on a faster way. Up to now VR has been used in patients with Parkinson disease (PD) as a research tool and none of the developed systems are used in clinical practice. The goal of this project is to develop a VR-based system for gait therapy, and gait research of patients with PD designed based on published evidence. The developed system uses a digital camera to measure spatiotemporal gait parameters. The software was developed in C#, using Open-Source libraries that facilitates VR programming. The system has potential uses in clinical and research settings.

A mechanized gait trainer for restoring gait in nonambulatory subjects.

PubMed

Hesse, S; Uhlenbrock, D; Werner, C; Bardeleben, A

2000-09-01

To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. DEVICE: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40% to 60% between swing and stance phases), supports the subjects according to their ability (lifts the foot during swing phase), and controls the center of mass in the vertical and horizontal directions. Two nonambulatory, hemiparetic patients who regained their walking ability after 4 weeks of daily training on the gait trainer, a 55-year-old woman and a 62-year-old man, both of whom had a first-time ischemic stroke. Four weeks of training, five times a week, each session 20 minutes long. Functional ambulation category (FAC, levels 0-5) to assess gait ability and ground level walking velocity. Rivermead motor assessment score (RMAS, 0-13) to assess gross motor function. Patient 1: At the end of treatment, she was able to walk independently on level ground with use of a walking stick. Her walking velocity had improved from .29m/sec to .59m/sec. Her RMAS score increased from 4 to 10, meaning she could walk at least 40 meters outside, pick up objects from floor, and climb stairs independently. Patient 2: At end of 4-week training, he could walk independently on even surfaces (FAC level 4), using an ankle-foot orthosis and a walking stick. His walking velocity improved from .14m/sec to .63m/sec. His RMAS increased from 3 to 10. The gait trainer enabled severely affected patients the repetitive practice of a gaitlike movement. Future studies may elucidate its value in gait rehabilitation of nonambulatory subjects.

A Voxel-Based Approach to Explore Local Dose Differences Associated With Radiation-Induced Lung Damage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Palma, Giuseppe; Monti, Serena; D'Avino, Vittoria

Purpose: To apply a voxel-based (VB) approach aimed at exploring local dose differences associated with late radiation-induced lung damage (RILD). Methods and Materials: An interinstitutional database of 98 patients who were Hodgkin lymphoma (HL) survivors treated with postchemotherapy supradiaphragmatic radiation therapy was analyzed in the study. Eighteen patients experienced late RILD, classified according to the Radiation Therapy Oncology Group scoring system. Each patient's computed tomographic (CT) scan was normalized to a single reference case anatomy (common coordinate system, CCS) through a log-diffeomorphic approach. The obtained deformation fields were used to map the dose of each patient into the CCS. Themore » coregistration robustness and the dose mapping accuracy were evaluated by geometric and dose scores. Two different statistical mapping schemes for nonparametric multiple permutation inference on dose maps were applied, and the corresponding P<.05 significance lung subregions were generated. A receiver operating characteristic (ROC)-based test was performed on the mean dose extracted from each subregion. Results: The coregistration process resulted in a geometrically robust and accurate dose warping. A significantly higher dose was consistently delivered to RILD patients in voxel clusters near the peripheral medial-basal portion of the lungs. The area under the ROC curves (AUC) from the mean dose of the voxel clusters was higher than the corresponding AUC derived from the total lung mean dose. Conclusions: We implemented a framework including a robust registration process and a VB approach accounting for the multiple comparison problem in dose-response modeling, and applied it to a cohort of HL survivors to explore a local dose–RILD relationship in the lungs. Patients with RILD received a significantly greater dose in parenchymal regions where low doses (∼6 Gy) were delivered. Interestingly, the relation between differences in the high

Rotating and translating anthropomorphic head voxel models to establish an horizontal Frankfort plane for dental CBCT Monte Carlo simulations: a dose comparison study

NASA Astrophysics Data System (ADS)

Stratis, A.; Zhang, G.; Jacobs, R.; Bogaerts, R.; Bosmans, H.

2016-12-01

In order to carry out Monte Carlo (MC) dosimetry studies, voxel phantoms, modeling human anatomy, and organ-based segmentation of CT image data sets are applied to simulation frameworks. The resulting voxel phantoms preserve patient CT acquisition geometry; in the case of head voxel models built upon head CT images, the head support with which CT scanners are equipped introduces an inclination to the head, and hence to the head voxel model. In dental cone beam CT (CBCT) imaging, patients are always positioned in such a way that the Frankfort line is horizontal, implying that there is no head inclination. The orientation of the head is important, as it influences the distance of critical radiosensitive organs like the thyroid and the esophagus from the x-ray tube. This work aims to propose a procedure to adjust head voxel phantom orientation, and to investigate the impact of head inclination on organ doses in dental CBCT MC dosimetry studies. The female adult ICRP, and three in-house-built paediatric voxel phantoms were in this study. An EGSnrc MC framework was employed to simulate two commonly used protocols; a Morita Accuitomo 170 dental CBCT scanner (FOVs: 60  ×  60 mm2 and 80  ×  80 mm2, standard resolution), and a 3D Teeth protocol (FOV: 100  ×  90 mm2) in a Planmeca Promax 3D MAX scanner. Result analysis revealed large absorbed organ dose differences in radiosensitive organs between the original and the geometrically corrected voxel models of this study, ranging from  -45.6% to 39.3%. Therefore, accurate dental CBCT MC dose calculations require geometrical adjustments to be applied to head voxel models.

Subliminal gait initiation deficits in REM sleep behavior disorder: a harbinger of freezing of gait?

PubMed Central

Alibiglou, L.; Videnovic, A.; Planetta, P.J.; Vaillancourt, D.E.; MacKinnon, C.D.

2016-01-01

Background Muscle activity during REM sleep is markedly increased in people with REM sleep behavior disorder (RBD) and people with Parkinson’s disease (PD) who have freezing of gait. This study examined if individuals with RBD, who do not have a diagnosis of PD, show abnormalities in gait initiation that resemble the impairments observed in PD and whether there is a relationship between these deficits and the level of REM sleep without atonia. Methods Gait initiation and polysomnography studies were conducted in four groups of 10 subjects each: RBD, PD with and without freezing of gait and control subjects. Results Significant reductions were seen in the posterior shift of the center of pressure during the propulsive phase of gait initiation in the RBD and PD with freezing of gait groups compared with controls and PD non-freezers. These reductions negatively correlated with the amount of REM sleep without atonia. The duration of the initial dorsiflexor muscle burst during gait initiation was significantly reduced in both PD groups and the RBD cohort. Conclusions These results provide evidence that people with RBD, prior to a diagnosis of a degenerative neurologic disorder, show alterations in the coupling of posture and gait similar to those seen in PD. The correlation between increased REM sleep without atonia and deficits in forward propulsion during the push-off phase of gait initiation suggests that abnormities in the regulation of muscle tone during REM sleep may be related to the pathogenesis of freezing of gait. PMID:27250871

Capability of 2 gait measures for detecting response to gait training in stroke survivors: Gait Assessment and Intervention Tool and the Tinetti Gait Scale.

PubMed

Zimbelman, Janice; Daly, Janis J; Roenigk, Kristen L; Butler, Kristi; Burdsall, Richard; Holcomb, John P

2012-01-01

To characterize the performance of 2 observational gait measures, the Tinetti Gait Scale (TGS) and the Gait Assessment and Intervention Tool (G.A.I.T.), in identifying improvement in gait in response to gait training. In secondary analysis from a larger study of multimodal gait training for stroke survivors, we measured gait at pre-, mid-, and posttreatment according to G.A.I.T. and TGS, assessing their capability to capture recovery of coordinated gait components. Large medical center. Cohort of stroke survivors (N=44) greater than 6 months after stroke. All subjects received 48 sessions of a multimodal gait-training protocol. Treatment consisted of 1.5 hours per session, 4 sessions per week for 12 weeks, receiving these 3 treatment aspects: (1) coordination exercise, (2) body weight-supported treadmill training, and (3) overground gait training, with 46% of subjects receiving functional electrical stimulation. All subjects were evaluated with the G.A.I.T. and TGS before and after completing the 48-session intervention. An additional evaluation was performed at midtreatment (after session 24). For the total subject sample, there were significant pre-/post-, pre-/mid-, and mid-/posttreatment gains for both the G.A.I.T. and the TGS. According to the G.A.I.T., 40 subjects (91%) showed improved scores, 2 (4%) no change, and 2 (4%) a worsening score. According to the TGS, only 26 subjects (59%) showed improved scores, 16 (36%) no change, and 1 (2%) a worsening score. For 1 treatment group of chronic stroke survivors, the TGS failed to identify a significant treatment response to gait training, whereas the G.A.I.T. measure was successful. The G.A.I.T. is more sensitive than the TGS for individual patients and group treatment response in identifying recovery of volitional control of gait components in response to gait training. Copyright © 2012 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

An Effective Algorithm Research of Scenario Voxelization Organization and Occlusion Culling

NASA Astrophysics Data System (ADS)

Lai, Guangling; Ding, Lu; Qin, Zhiyuan; Tong, Xiaochong

2016-11-01

Compared with the traditional triangulation approaches, the voxelized point cloud data can reduce the sensitivity of scenario and complexity of calculation. While on the base of the point cloud data, implementation scenario organization could be accomplishment by subtle voxel, but it will add more memory consumption. Therefore, an effective voxel representation method is very necessary. At present, the specific study of voxel visualization algorithm is less. This paper improved the ray tracing algorithm by the characteristics of voxel configuration. Firstly, according to the scope of point cloud data, determined the scope of the pixels on the screen. Then, calculated the light vector came from each pixel. Lastly, used the rules of voxel configuration to calculate all the voxel penetrated through by light. The voxels closest to viewpoint were named visible ones, the rest were all obscured ones. This experimental showed that the method could realize voxelization organization and voxel occlusion culling of implementation scenario efficiently, and increased the render efficiency.

Balance and gait improved in patients with MS after physiotherapy based on the Bobath concept.

PubMed

Smedal, Tori; Lygren, Hildegunn; Myhr, Kjell-Morten; Moe-Nilssen, Rolf; Gjelsvik, Bente; Gjelsvik, Olav; Strand, Liv Inger; Inger, Liv

2006-06-01

Patients with multiple sclerosis (MS) tend to have movement difficulties, and the effect of physiotherapy for this group of patients has been subjected to limited systematic research. In the present study physiotherapy based on the Bobath concept, applied to MS patients with balance and gait problems, was evaluated. The ability of different functional tests to demonstrate change was evaluated. A single-subject experimental study design with ABAA phases was used, and two patients with relapsing-remitting MS in stable phase were treated. Tests were performed 12 times, three at each phase: A (at baseline); B (during treatment); A (immediately after treatment); and A (after two months). The key feature of treatment was facilitation of postural activity and selective control of movement. Several performance and self report measures and interviews were used. After intervention, improved balance was shown by the Berg Balance Scale (BBS) in both patients, and improved quality of gait was indicated by the Rivermead Visual Gait Assessment (RVGA). The patients also reported improved balance and gait function in the interviews and scored their condition as 'much improved'. Gait parameters, recorded by an electronic walkway, changed, but differently in the two patients. Among the physical performance tests the BBS and the RVGA demonstrated the highest change, while no or minimal change was demonstrated by the Rivermead Mobility Index (RMI) and Ratings of Perceived Exertion (RPE). The findings indicate that balance and gait can be improved after physiotherapy based on the Bobath concept, but this should be further evaluated in larger controlled trials of patients with MS.

Feature selection gait-based gender classification under different circumstances

NASA Astrophysics Data System (ADS)

Sabir, Azhin; Al-Jawad, Naseer; Jassim, Sabah

2014-05-01

This paper proposes a gender classification based on human gait features and investigates the problem of two variations: clothing (wearing coats) and carrying bag condition as addition to the normal gait sequence. The feature vectors in the proposed system are constructed after applying wavelet transform. Three different sets of feature are proposed in this method. First, Spatio-temporal distance that is dealing with the distance of different parts of the human body (like feet, knees, hand, Human Height and shoulder) during one gait cycle. The second and third feature sets are constructed from approximation and non-approximation coefficient of human body respectively. To extract these two sets of feature we divided the human body into two parts, upper and lower body part, based on the golden ratio proportion. In this paper, we have adopted a statistical method for constructing the feature vector from the above sets. The dimension of the constructed feature vector is reduced based on the Fisher score as a feature selection method to optimize their discriminating significance. Finally k-Nearest Neighbor is applied as a classification method. Experimental results demonstrate that our approach is providing more realistic scenario and relatively better performance compared with the existing approaches.

An investigation of voxel geometries for MCNP-based radiation dose calculations.

PubMed

Zhang, Juying; Bednarz, Bryan; Xu, X George

2006-11-01

Voxelized geometry such as those obtained from medical images is increasingly used in Monte Carlo calculations of absorbed doses. One useful application of calculated absorbed dose is the determination of fluence-to-dose conversion factors for different organs. However, confusion still exists about how such a geometry is defined and how the energy deposition is best computed, especially involving a popular code, MCNP5. This study investigated two different types of geometries in the MCNP5 code, cell and lattice definitions. A 10 cm x 10 cm x 10 cm test phantom, which contained an embedded 2 cm x 2 cm x 2 cm target at its center, was considered. A planar source emitting parallel photons was also considered in the study. The results revealed that MCNP5 does not calculate total target volume for multi-voxel geometries. Therefore, tallies which involve total target volume must be divided by the user by the total number of voxels to obtain a correct dose result. Also, using planar source areas greater than the phantom size results in the same fluence-to-dose conversion factor.

Asymmetry in gait pattern following bicondylar tibial plateau fractures-A prospective one-year cohort study.

PubMed

Elsoe, Rasmus; Larsen, Peter

2017-07-01

Despite the high number of studies evaluating outcomes following tibial plateau fractures, the literature lacks studies including the objective assessment of gait pattern. The purpose of the present study was to evaluate asymmetry in gait patterns at 12 months after frame removal following ring fixation of a tibial plateau fracture. The study design was a prospective cohort study. The primary outcome measurement was the gait patterns 12 months after frame removal measured with a pressure-sensitive mat. The mat registers footprints and present gait speed, cadence, as well as temporal and spatial parameters of the gait cycle. Gait patterns were compared to a healthy reference population. Twenty-three patients were included with a mean age of 54.4 years (32-78 years). Patients presented with a shorter step-length of the injured leg compared to the non-injured leg (asymmetry of 11.3%). Analysis of single-support showed shorter support time of the injured leg compared to the non-injured leg (asymmetry of 8.7%). Moreover, analysis of swing-time showed increased swing-time of the injured leg (asymmetry of 8.9%). Compared to a healthy reference population, increased asymmetry in all gait patterns was observed. The association between asymmetry and health-related quality of life (HRQOL) showed moderate associations (single-support: R=0.50, P=0.03; step-length: R=0.43, P=0.07; swing-time: R=0.46, P=0.05). Compared to a healthy reference population, gait asymmetry is common 12 months after frame removal in patients treated with external ring fixation following a tibial plateau fracture of the tibia. Copyright © 2017 Elsevier Ltd. All rights reserved.

To pace or not to pace: a pilot study of four- and five-gaited Icelandic horses homozygous for the DMRT3 'Gait Keeper' mutation.

PubMed

Jäderkvist Fegraeus, K; Hirschberg, I; Árnason, T; Andersson, L; Velie, B D; Andersson, L S; Lindgren, G

2017-12-01

The Icelandic horse is a breed known mainly for its ability to perform the ambling four-beat gait 'tölt' and the lateral two-beat gait pace. The natural ability of the breed to perform these alternative gaits is highly desired by breeders. Therefore, the discovery that a nonsense mutation (C>A) in the DMRT3 gene was the main genetic factor for horses' ability to perform gaits in addition to walk, trot and canter was of great interest. Although several studies have demonstrated that homozygosity for the DMRT3 mutation is important for the ability to pace, only about 70% of the homozygous mutant (AA) Icelandic horses are reported to pace. The aim of the study was to genetically compare four- and five-gaited (i.e. horses with and without the ability to pace) AA Icelandic horses by performing a genome-wide association (GWA) analysis. All horses (n = 55) were genotyped on the 670K Axiom Equine Genotyping Array, and a GWA analysis was performed using the genabel package in r. No SNP demonstrated genome-wide significance, implying that the ability to pace goes beyond the presence of a single gene variant. Despite its limitations, the current study provides additional information regarding the genetic complexity of pacing ability in horses. However, to fully understand the genetic differences between four- and five-gaited AA horses, additional studies with larger sample materials and consistent phenotyping are needed. © 2017 Stichting International Foundation for Animal Genetics.

Wearable sensors objectively measure gait parameters in Parkinson’s disease

PubMed Central

Marxreiter, Franz; Gossler, Julia; Kohl, Zacharias; Reinfelder, Samuel; Gassner, Heiko; Aminian, Kamiar; Eskofier, Bjoern M.; Winkler, Jürgen; Klucken, Jochen

2017-01-01

Distinct gait characteristics like short steps and shuffling gait are prototypical signs commonly observed in Parkinson’s disease. Routinely assessed by observation through clinicians, gait is rated as part of categorical clinical scores. There is an increasing need to provide quantitative measurements of gait, e.g. to provide detailed information about disease progression. Recently, we developed a wearable sensor-based gait analysis system as diagnostic tool that objectively assesses gait parameter in Parkinson’s disease without the need of having a specialized gait laboratory. This system consists of inertial sensor units attached laterally to both shoes. The computed target of measures are spatiotemporal gait parameters including stride length and time, stance phase time, heel-strike and toe-off angle, toe clearance, and inter-stride variation from gait sequences. To translate this prototype into medical care, we conducted a cross-sectional study including 190 Parkinson’s disease patients and 101 age-matched controls and measured gait characteristics during a 4x10 meter walk at the subjects’ preferred speed. To determine intraindividual changes in gait, we monitored the gait characteristics of 63 patients longitudinally. Cross-sectional analysis revealed distinct spatiotemporal gait parameter differences reflecting typical Parkinson’s disease gait characteristics including short steps, shuffling gait, and postural instability specific for different disease stages and levels of motor impairment. The longitudinal analysis revealed that gait parameters were sensitive to changes by mirroring the progressive nature of Parkinson’s disease and corresponded to physician ratings. Taken together, we successfully show that wearable sensor-based gait analysis reaches clinical applicability providing a high biomechanical resolution for gait impairment in Parkinson’s disease. These data demonstrate the feasibility and applicability of objective wearable sensor-based

A Feasibility Study of View-independent Gait Identification

DTIC Science & Technology

2012-03-01

ice skates . For walking, the footprint records for single pixels form clusters that are well separated in space and time. (Any overlap of contact...Pattern Recognition 2007, 1-8. Cheng M-H, Ho M-F & Huang C-L (2008), "Gait Analysis for Human Identification Through Manifold Learning and HMM... Learning and Cybernetics 2005, 4516-4521 Moeslund T B & Granum E (2001), "A Survey of Computer Vision-Based Human Motion Capture", Computer Vision

Grey matter, an endophenotype for schizophrenia? A voxel-based morphometry study in siblings of patients with schizophrenia.

PubMed

van der Velde, Jorien; Gromann, Paula M; Swart, Marte; de Haan, Lieuwe; Wiersma, Durk; Bruggeman, Richard; Krabbendam, Lydia; Aleman, André

2015-05-01

Grey matter, both volume and concentration, has been proposed as an endophenotype for schizophrenia given a number of reports of grey matter abnormalities in relatives of patients with schizophrenia. However, previous studies on grey matter abnormalities in relatives have produced inconsistent results. The aim of the present study was to examine grey matter differences between controls and siblings of patients with schizophrenia and to examine whether the age, genetic loading or subclinical psychotic symptoms of selected individuals could explain the previously reported inconsistencies. We compared the grey matter volume and grey matter concentration of healthy siblings of patients with schizophrenia and healthy controls matched for age, sex and education using voxel-based morphometry (VBM). Furthermore, we selected subsamples based on age (< 30 yr), genetic loading and subclinical psychotic symptoms to examine whether this would lead to different results. We included 89 siblings and 69 controls in our study. The results showed that siblings and controls did not differ significantly on grey matter volume or concentration. Furthermore, specifically selecting participants based on age, genetic loading or subclinical psychotic symptoms did not alter these findings. The main limitation was that subdividing the sample resulted in smaller samples for the subanalyses. Furthermore, we used MRI data from 2 different scanner sites. These results indicate that grey matter measured through VBM might not be a suitable endophenotype for schizophrenia.

Gait Planning and Stability Control of a Quadruped Robot

PubMed Central

Li, Junmin; Wang, Jinge; Yang, Simon X.; Zhou, Kedong; Tang, Huijuan

2016-01-01

In order to realize smooth gait planning and stability control of a quadruped robot, a new controller algorithm based on CPG-ZMP (central pattern generator-zero moment point) is put forward in this paper. To generate smooth gait and shorten the adjusting time of the model oscillation system, a new CPG model controller and its gait switching strategy based on Wilson-Cowan model are presented in the paper. The control signals of knee-hip joints are obtained by the improved multi-DOF reduced order control theory. To realize stability control, the adaptive speed adjustment and gait switch are completed by the real-time computing of ZMP. Experiment results show that the quadruped robot's gaits are efficiently generated and the gait switch is smooth in the CPG control algorithm. Meanwhile, the stability of robot's movement is improved greatly with the CPG-ZMP algorithm. The algorithm in this paper has good practicability, which lays a foundation for the production of the robot prototype. PMID:27143959

Gait Planning and Stability Control of a Quadruped Robot.

PubMed

Li, Junmin; Wang, Jinge; Yang, Simon X; Zhou, Kedong; Tang, Huijuan

2016-01-01

In order to realize smooth gait planning and stability control of a quadruped robot, a new controller algorithm based on CPG-ZMP (central pattern generator-zero moment point) is put forward in this paper. To generate smooth gait and shorten the adjusting time of the model oscillation system, a new CPG model controller and its gait switching strategy based on Wilson-Cowan model are presented in the paper. The control signals of knee-hip joints are obtained by the improved multi-DOF reduced order control theory. To realize stability control, the adaptive speed adjustment and gait switch are completed by the real-time computing of ZMP. Experiment results show that the quadruped robot's gaits are efficiently generated and the gait switch is smooth in the CPG control algorithm. Meanwhile, the stability of robot's movement is improved greatly with the CPG-ZMP algorithm. The algorithm in this paper has good practicability, which lays a foundation for the production of the robot prototype.

Voxel-by-voxel analysis of brain SPECT perfusion in Fibromyalgia

NASA Astrophysics Data System (ADS)

Guedj, Eric; Taïeb, David; Cammilleri, Serge; Lussato, David; de Laforte, Catherine; Niboyet, Jean; Mundler, Olivier

2007-02-01

We evaluated brain perfusion SPECT at rest, without noxious stiumuli, in a homogeneous group of hyperalgesic FM patients. We performed a voxel-based analysis in comparison to a control group, matched for age and gender. Under such conditions, we made the assumption that significant cerebral perfusion abnormalities could be demonstrated, evidencing altered cerebral processing associated with spontaneous pain in FM patients. The secondary objective was to study the reversibility and the prognostic value of such possible perfusion abnormalities under specific treatment. Eighteen hyperalgesic FM women (mean age 48 yr; range 25-63 yr; ACR criteria) and 10 healthy women matched for age were enrolled in the study. A voxel-by-voxel group analysis was performed using SPM2 ( p<0.05, corrected for multiple comparisons). All brain SPECT were performed before any change was made in therapy in the pain care unit. A second SPECT was performed a month later after specific treatment by Ketamine. Compared to control subjects, we observed individual brain SPECT abnormalities in FM patients, confirmed by SPM2 analysis with hyperperfusion of the somatosensory cortex and hypoperfusion of the frontal, cingulate, medial temporal and cerebellar cortices. We also found that a medial frontal and anterior cingulate hypoperfusions were highly predictive (PPV=83%; NPV=91%) of non-response on Ketamine, and that only responders showed significant modification of brain perfusion, after treatment. In the present study performed without noxious stimuli in hyperalgesic FM patients, we found significant hyperperfusion in regions of the brain known to be involved in sensory dimension of pain processing and significant hypoperfusion in areas assumed to be associated with the affective dimension. As current pharmacological and non-pharmacological therapies act differently on both components of pain, we hypothesize that SPECT could be a valuable and readily available tool to guide individual therapeutic

A voxel-based morphometry study of regional gray and white matter correlate of self-disclosure.

PubMed

Wang, ShanShan; Wei, DongTao; Li, WenFu; Li, HaiJiang; Wang, KangCheng; Xue, Song; Zhang, Qinglin; Qiu, Jiang

2014-01-01

Self-disclosure is an important performance in human social communication. Generally, an individual is likely to have a good physical and mental health if he is prone to self-disclosure under stressful life events. However, as for now, little is known about the neural structure associated with self-disclosure. Therefore, in this study, we used voxel-based morphometry to explore regional gray matter volume (rGMV) and white matter volume (rWMV) associated with self-disclosure measured by the Jourard Self-disclosure Questionnaire in a large sample of college students. Results showed that individual self-disclosure was significantly and positively associated with rGMV of the left postcentral gyrus, which might be related to strengthen individual's ability of body feeling; while self-disclosure was significantly and negatively associated with rGMV of the right orbitofrontal cortex (OFC), which might be involved in increased positive emotion experience seeking (intrinsically rewarding). In addition, individual self-disclosure was also associated with smaller rWMV in the right inferior parietal lobule (IPL). These findings suggested a biological basis for individual self-disclosure, distributed across different gray and white matter areas of the brain.

Gait outcome following outpatient physiotherapy based on the Bobath concept in people post stroke.

PubMed

Lennon, Sheila; Ashburn, Ann; Baxter, David

The purpose of this study was to characterize the gait cycle of patients with hemiplegia before and after a period of outpatient physiotherapy based on the Bobath concept. Nine patients, at least 6 weeks post stroke and recently discharged from a stroke unit, were measured before and after a period of outpatient physiotherapy (mean duration = 17.4 weeks). Therapy was documented using a treatment checklist for each patient. The primary outcome measures were a number of gait variables related to the therapists' treatment hypothesis, recorded during the gait cycle using the CODA motion analysis system. Other secondary outcome measures were the Motor Assessment Scale, Modified Ashworth Scale, subtests of the Sodring Motor Evaluation Scale, the Step test, a 10-m walk test, the Barthel Index and the London Handicap Score. Recovery of more normal gait patterns in the gait cycle (using motion analysis) did not occur. Significant changes in temporal parameters (loading response, single support time) for both legs, in one kinematic (dorsiflexion during stance) and one kinetic variable on the unaffected side (hip flexor moment), and most of the clinical measures of impairment, activity and participation (with the exception of the Modified Ashworth Scale and the 10-m walk) were noted. Study findings did not support the hypothesis that the Bobath approach restored more normal movement patterns to the gait cycle. Further research is required to investigate the treatment techniques that are effective at improving walking ability in people after stroke.

Classification of Normal and Pathological Gait in Young Children Based on Foot Pressure Data.

PubMed

Guo, Guodong; Guffey, Keegan; Chen, Wenbin; Pergami, Paola

2017-01-01

Human gait recognition, an active research topic in computer vision, is generally based on data obtained from images/videos. We applied computer vision technology to classify pathology-related changes in gait in young children using a foot-pressure database collected using the GAITRite walkway system. As foot positioning changes with children's development, we also investigated the possibility of age estimation based on this data. Our results demonstrate that the data collected by the GAITRite system can be used for normal/pathological gait classification. Combining age information and normal/pathological gait classification increases the accuracy of the classifier. This novel approach could support the development of an accurate, real-time, and economic measure of gait abnormalities in children, able to provide important feedback to clinicians regarding the effect of rehabilitation interventions, and to support targeted treatment modifications.

Balance and gait in older electroconvulsive therapy recipients: a pilot study

PubMed Central

Plakiotis, Chris; Barson, Fay; Vengadasalam, Bharathi; Haines, Terry P; O’Connor, Daniel W

2013-01-01

Background Electroconvulsive therapy (ECT) is commonly used to treat depression in older adults. Despite its efficacy in this regard, an associated increase in the risk of falls in this population is a downside of treatment. ECT research has focused on the incidence of falls, but its effect on balance and gait – intrinsic factors in instability and falls – has not been studied. Our aim was to examine changes in balance and gait among older adults before and after a single ECT session and explore the effect of patient-related and treatment factors on any changes found. Methods Participants were 21 older adults requiring ECT for depression in public psychiatric services. Patients with clinically overt mobility problems (impairing test participation or increasing the risk of falls) were excluded. Balance and gait testing 1 hour pre-ECT and 1, 2 and 3 hours post-ECT included: (1) steady standing test; (2) perturbation of standing balance by self-initiated movements; (3) perturbation of standing balance by an external perturbation; and (4) timed up and go test. Results No deterioration in test performance was found, using one-way repeated measures analysis of variance. Conclusion Balance and gait did not deteriorate immediately after ECT. Exclusion of participants with clinically overt mobility problems and falls being better attributable to factors unrelated to balance and gait (such as post-ECT confusion) may account for our findings. This research does not repudiate the occurrence of ECT-related falls but calls into question the utility of introducing routine balance and gait assessment among older ECT recipients without pre-existing mobility problems as a means of preventing them. PMID:23766650

Assessment of gait in subcortical vascular encephalopathy by computerized analysis: a cross-sectional and longitudinal study.

PubMed

Bäzner, H; Oster, M; Daffertshofer, M; Hennerici, M

2000-11-01

In subcortical vascular encephalopathy (SVE) gait disturbance is a common and early clinical sign which might be used to monitor disease progression. In the absence of reliable scales and with regard to the equivocal results of highly complex gait imaging devices we assessed the natural course of SVE in a prospective study, using a new straight forward technique to quantify and compare sequential gait studies. We report the results of 300 computerized gait analyses in 119 patients with SVE and 63 age-matched controls. Thirty-nine SVE patients were re-evaluated to monitor the natural course of the disease and to study the correlation of gait disturbances with MRI changes and neuropsychological findings. The system consists of a set of shoes containing 16 load sensors and a measuring-unit reading each sensor at 20-ms intervals. By off-line analysis we graded each recording on a Gait Disorder Score (GDS) with six variables indicating gait steadiness: step frequency, length of gait lines (which represent the movement of the centre of gravity during heel to toe movement), length of single support lines, variability of single and of double support lines, and double support time. In cross-sectional analysis, patients with SVE showed cadence (steps/min) to be reduced at 87.3 +/- 19.5 (96.4 +/- 7.8 in controls, P < 0.05). Length of gait lines was significantly less: 0.70 +/- 0.13 vs. 0.80 +/- 0.05 in controls, with length of single support gait lines reduced at 0.42 +/- 0.14 in SVE (0.58 +/- 0.06 in controls, P < 0.05). Variability of both single support lines (5.69 +/- 1.90%; 4.24 +/- 1.07% in controls, P < 0.05) and double support lines was elevated (3.59 +/- 1.62% vs. 2.54 +/- 0.59%), while duration of double support phases was increased (0.19 +/- 0.10 s vs. 0.13 +/- 0.02 s in controls, P < 0.05). The progressive character of the disease was demonstrated by increasing GDS values in 39 SVE patients with a frontal gait disorder who were re-investigated after a mean

Diffusion tensor imaging of nigral degeneration in Parkinson's disease: A region-of-interest and voxel-based study at 3 T and systematic review with meta-analysis☆

PubMed Central

Schwarz, Stefan T.; Abaei, Maryam; Gontu, Vamsi; Morgan, Paul S.; Bajaj, Nin; Auer, Dorothee P.

2013-01-01

There is increasing interest in developing a reliable, affordable and accessible disease biomarker of Parkinson's disease (PD) to facilitate disease modifying PD-trials. Imaging biomarkers using magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) can describe parameters such as fractional anisotropy (FA), mean diffusivity (MD) or apparent diffusion coefficient (ADC). These parameters, when measured in the substantia nigra (SN), have not only shown promising but also varying and controversial results. To clarify the potential diagnostic value of nigral DTI in PD and its dependency on selection of region-of-interest, we undertook a high resolution DTI study at 3 T. 59 subjects (32 PD patients, 27 age and sex matched healthy controls) were analysed using manual outlining of SN and substructures, and voxel-based analysis (VBA). We also performed a systematic literature review and meta-analysis to estimate the effect size (DES) of disease related nigral DTI changes. We found a regional increase in nigral mean diffusivity in PD (mean ± SD, PD 0.80 ± 0.10 vs. controls 0.73 ± 0.06 · 10− 3 mm2/s, p = 0.002), but no difference using a voxel based approach. No significant disease effect was seen using meta-analysis of nigral MD changes (10 studies, DES = + 0.26, p = 0.17, I2 = 30%). None of the nigral regional or voxel based analyses of this study showed altered fractional anisotropy. Meta-analysis of 11 studies on nigral FA changes revealed a significant PD induced FA decrease. There was, however, a very large variation in results (I2 = 86%) comparing all studies. After exclusion of five studies with unusual high values of nigral FA in the control group, an acceptable heterogeneity was reached, but there was non-significant disease effect (DES = − 0.5, p = 0.22, I2 = 28%). The small PD related nigral MD changes in conjunction with the negative findings on VBA and meta-analysis limit the usefulness of nigral MD measures as

White matter and schizophrenia: A meta-analysis of voxel-based morphometry and diffusion tensor imaging studies.

PubMed

Vitolo, Enrico; Tatu, Mona Karina; Pignolo, Claudia; Cauda, Franco; Costa, Tommaso; Ando', Agata; Zennaro, Alessandro

2017-12-30

Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) are the most implemented methodologies to detect alterations of both gray and white matter (WM). However, the role of WM in mental disorders is still not well defined. We aimed at clarifying the role of WM disruption in schizophrenia and at identifying the most frequently involved brain networks. A systematic literature search was conducted to identify VBM and DTI studies focusing on WM alterations in patients with schizophrenia compared to control subjects. We selected studies reporting the coordinates of WM reductions and we performed the anatomical likelihood estimation (ALE). Moreover, we labeled the WM bundles with an anatomical atlas and compared VBM and DTI ALE-scores of each significant WM tract. A total of 59 studies were eligible for the meta-analysis. WM alterations were reported in 31 and 34 foci with VBM and DTI methods, respectively. The most occurred WM bundles in both VBM and DTI studies and largely involved in schizophrenia were long projection fibers, callosal and commissural fibers, part of motor descending fibers, and fronto-temporal-limbic pathways. The meta-analysis showed a widespread WM disruption in schizophrenia involving specific cerebral circuits instead of well-defined regions. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced data consistency of a portable gait measurement system.

PubMed

Lin, Hsien-I; Chiang, Y P

2013-11-01

A gait measurement system is a useful tool for rehabilitation applications. Such a system is used to conduct gait experiments in large workplaces such as laboratories where gait measurement equipment can be permanently installed. However, a gait measurement system should be portable if it is to be used in clinics or community centers for aged people. In a portable gait measurement system, the workspace is limited and landmarks on a subject may not be visible to the cameras during experiments. Thus, we propose a virtual-marker function to obtain positions of unseen landmarks for maintaining data consistency. This work develops a portable clinical gait measurement system consisting of lightweight motion capture devices, force plates, and a walkway assembled from plywood boards. We evaluated the portable clinic gait system with 11 normal subjects in three consecutive days in a limited experimental space. Results of gait analysis based on the verification of within-day and between-day coefficients of multiple correlations show that the proposed portable gait system is reliable.

Enhanced data consistency of a portable gait measurement system

NASA Astrophysics Data System (ADS)

Lin, Hsien-I.; Chiang, Y. P.

2013-11-01

A gait measurement system is a useful tool for rehabilitation applications. Such a system is used to conduct gait experiments in large workplaces such as laboratories where gait measurement equipment can be permanently installed. However, a gait measurement system should be portable if it is to be used in clinics or community centers for aged people. In a portable gait measurement system, the workspace is limited and landmarks on a subject may not be visible to the cameras during experiments. Thus, we propose a virtual-marker function to obtain positions of unseen landmarks for maintaining data consistency. This work develops a portable clinical gait measurement system consisting of lightweight motion capture devices, force plates, and a walkway assembled from plywood boards. We evaluated the portable clinic gait system with 11 normal subjects in three consecutive days in a limited experimental space. Results of gait analysis based on the verification of within-day and between-day coefficients of multiple correlations show that the proposed portable gait system is reliable.

Continuous positive airway pressure improves gait control in severe obstructive sleep apnoea: A prospective study

PubMed Central

Wuyam, Bernard; Pépin, Jean-Louis; Marillier, Mathieu; Tamisier, Renaud; Pérennou, Dominic; Verges, Samuel

2018-01-01

Study aim Severe obstructive sleep apnoea (OSA) can lead to neurocognitive alterations, including gait impairments. The beneficial effects of continuous positive airway pressure (CPAP) on improving excessive daytime sleepiness and daily functioning have been documented. However, a demonstration of CPAP treatment efficacy on gait control is still lacking. This study aims to test the hypothesis that CPAP improves gait control in severe OSA patients. Material and methods In this prospective controlled study, twelve severe OSA patients (age = 57.2±8.9 years, body mass index = 27.4±3.1 kg·m-2, apnoea-hypopnoea index = 46.3±11.7 events·h-1) and 10 healthy matched subjects were included. Overground gait parameters were recorded at spontaneous speed and stride time variability, a clinical marker of gait control, was calculated. To assess the role of executive functions in gait and postural control, a dual-task paradigm was applied using a Stroop test as secondary cognitive task. All assessments were performed before and after 8 weeks of CPAP treatment. Results Before CPAP treatment, OSA patients had significantly larger stride time variability (3.1±1.1% vs 2.1±0.5%) and lower cognitive performances under dual task compared to controls. After CPAP treatment, stride time variability was significantly improved and no longer different compared to controls. Cognitive performance under dual task also improved after CPAP treatment. Conclusion Eight weeks of CPAP treatment improves gait control of severe OSA patients, suggesting morphological and functional cerebral improvements. Our data provide a rationale for further mechanistic studies and the use of gait as a biomarker of OSA brain consequences. PMID:29474363

Regional patterns of grey matter atrophy and magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups: a voxel-based analysis study.

PubMed

Mallik, Shahrukh; Muhlert, Nils; Samson, Rebecca S; Sethi, Varun; Wheeler-Kingshott, Claudia A M; Miller, David H; Chard, Declan T

2015-04-01

In multiple sclerosis (MS), demyelination and neuro-axonal loss occur in the brain grey matter (GM). We used magnetic resonance imaging (MRI) measures of GM magnetisation transfer ratio (MTR) and volume to assess the regional localisation of reduced MTR (reflecting demyelination) and atrophy (reflecting neuro-axonal loss) in relapsing-remitting MS (RRMS), secondary progressive MS (SPMS) and primary progressive MS (PPMS). A total of 98 people with MS (51 RRMS, 28 SPMS, 19 PPMS) and 29 controls had T1-weighted volumetric and magnetisation transfer scans. SPM8 was used to undertake voxel-based analysis (VBA) of GM tissue volumes and MTR. MS subgroups were compared with controls, adjusting for age and gender. A voxel-by-voxel basis correlation analysis between MTR and volume within each subject group was performed, using biological parametric mapping. MTR reduction was more extensive than atrophy. RRMS and SPMS patients showed proportionately more atrophy in the deep GM. SPMS and PPMS patients showed proportionately greater cortical MTR reduction. RRMS patients demonstrated the most correlation of MTR reduction and atrophy in deep GM. In SPMS and PPMS patients, there was less extensive correlation. These results suggest that in the deep GM of RRMS patients, demyelination and neuro-axonal loss may be linked, while in SPMS and PPMS patients, neuro-axonal loss and demyelination may occur mostly independently. © The Author(s), 2014.

Regional patterns of grey matter atrophy and magnetisation transfer ratio abnormalities in multiple sclerosis clinical subgroups: A voxel-based analysis study

PubMed Central

Muhlert, Nils; Samson, Rebecca S; Sethi, Varun; Wheeler-Kingshott, Claudia AM; Miller, David H; Chard, Declan T

2015-01-01

Background: In multiple sclerosis (MS), demyelination and neuro-axonal loss occur in the brain grey matter (GM). We used magnetic resonance imaging (MRI) measures of GM magnetisation transfer ratio (MTR) and volume to assess the regional localisation of reduced MTR (reflecting demyelination) and atrophy (reflecting neuro-axonal loss) in relapsing–remitting MS (RRMS), secondary progressive MS (SPMS) and primary progressive MS (PPMS). Methods: A total of 98 people with MS (51 RRMS, 28 SPMS, 19 PPMS) and 29 controls had T1-weighted volumetric and magnetisation transfer scans. SPM8 was used to undertake voxel-based analysis (VBA) of GM tissue volumes and MTR. MS subgroups were compared with controls, adjusting for age and gender. A voxel-by-voxel basis correlation analysis between MTR and volume within each subject group was performed, using biological parametric mapping. Results: MTR reduction was more extensive than atrophy. RRMS and SPMS patients showed proportionately more atrophy in the deep GM. SPMS and PPMS patients showed proportionately greater cortical MTR reduction. RRMS patients demonstrated the most correlation of MTR reduction and atrophy in deep GM. In SPMS and PPMS patients, there was less extensive correlation. Conclusions: These results suggest that in the deep GM of RRMS patients, demyelination and neuro-axonal loss may be linked, while in SPMS and PPMS patients, neuro-axonal loss and demyelination may occur mostly independently. PMID:25145689

Challenging Gait Conditions Predict 1-Year Decline in Gait Speed in Older Adults With Apparently Normal Gait

PubMed Central

Perera, Subashan; VanSwearingen, Jessie M.; Hile, Elizabeth S.; Wert, David M.; Studenski, Stephanie A.

2011-01-01

Background Mobility often is tested under a low challenge condition (ie, over a straight, uncluttered path), which often fails to identify early mobility difficulty. Tests of walking during challenging conditions may uncover mobility difficulty that is not identified with usual gait testing. Objective The purpose of this study was to determine whether gait during challenging conditions predicts decline in gait speed over 1 year in older people with apparently normal gait (ie, gait speed of ≥1.0 m/s). Design This was a prospective cohort study. Methods Seventy-one older adults (mean age=75.9 years) with a usual gait speed of ≥1.0 m/s participated. Gait was tested at baseline under 4 challenging conditions: (1) narrow walk (15 cm wide), (2) stepping over obstacles (15.24 cm [6 in] and 30.48 cm [12 in]), (3) simple walking while talking (WWT), and (4) complex WWT. Usual gait speed was recorded over a 4-m course at baseline and 1 year later. A 1-year change in gait speed was calculated, and participants were classified as declined (decreased ≥0.10 m/s, n=18), stable (changed <0.10 m/s, n=43), or improved (increased ≥0.10 m/s, n=10). Analysis of variance was used to compare challenging condition cost (usual − challenging condition gait speed difference) among the 3 groups. Results Participants who declined in the ensuing year had a greater narrow walk and obstacle walk cost than those who were stable or who improved in gait speed (narrow walk cost=0.43 versus 0.33 versus 0.22 m/s and obstacle walk cost=0.35 versus 0.26 versus 0.13 m/s). Simple and complex WWT cost did not differ among the groups. Limitations The participants who declined in gait speed over time walked the fastest, and those who improved walked the slowest at baseline; thus, the potential contribution of regression to the mean to the findings should not be overlooked. Conclusions In older adults with apparently normal gait, the assessment of gait during challenging conditions appears to uncover

A Personalized Multi-Channel FES Controller Based on Muscle Synergies to Support Gait Rehabilitation after Stroke.

PubMed

Ferrante, Simona; Chia Bejarano, Noelia; Ambrosini, Emilia; Nardone, Antonio; Turcato, Anna M; Monticone, Marco; Ferrigno, Giancarlo; Pedrocchi, Alessandra

2016-01-01

It has been largely suggested in neuroscience literature that to generate a vast variety of movements, the Central Nervous System (CNS) recruits a reduced set of coordinated patterns of muscle activities, defined as muscle synergies. Recent neurophysiological studies have recommended the analysis of muscle synergies to finely assess the patient's impairment, to design personalized interventions based on the specific nature of the impairment, and to evaluate the treatment outcomes. In this scope, the aim of this study was to design a personalized multi-channel functional electrical stimulation (FES) controller for gait training, integrating three novel aspects: (1) the FES strategy was based on healthy muscle synergies in order to mimic the neural solutions adopted by the CNS to generate locomotion; (2) the FES strategy was personalized according to an initial locomotion assessment of the patient and was designed to specifically activate the impaired biomechanical functions; (3) the FES strategy was mapped accurately on the altered gait kinematics providing a maximal synchronization between patient's volitional gait and stimulation patterns. The novel intervention was tested on two chronic stroke patients. They underwent a 4-week intervention consisting of 30-min sessions of FES-supported treadmill walking three times per week. The two patients were characterized by a mild gait disability (walking speed > 0.8 m/s) at baseline. However, before treatment both patients presented only three independent muscle synergies during locomotion, resembling two different gait abnormalities. After treatment, the number of extracted synergies became four and they increased their resemblance with the physiological muscle synergies, which indicated a general improvement in muscle coordination. The originally merged synergies seemed to regain their distinct role in locomotion control. The treatment benefits were more evident for one patient, who achieved a clinically important change

A Personalized Multi-Channel FES Controller Based on Muscle Synergies to Support Gait Rehabilitation after Stroke

PubMed Central

Ferrante, Simona; Chia Bejarano, Noelia; Ambrosini, Emilia; Nardone, Antonio; Turcato, Anna M.; Monticone, Marco; Ferrigno, Giancarlo; Pedrocchi, Alessandra

2016-01-01

It has been largely suggested in neuroscience literature that to generate a vast variety of movements, the Central Nervous System (CNS) recruits a reduced set of coordinated patterns of muscle activities, defined as muscle synergies. Recent neurophysiological studies have recommended the analysis of muscle synergies to finely assess the patient's impairment, to design personalized interventions based on the specific nature of the impairment, and to evaluate the treatment outcomes. In this scope, the aim of this study was to design a personalized multi-channel functional electrical stimulation (FES) controller for gait training, integrating three novel aspects: (1) the FES strategy was based on healthy muscle synergies in order to mimic the neural solutions adopted by the CNS to generate locomotion; (2) the FES strategy was personalized according to an initial locomotion assessment of the patient and was designed to specifically activate the impaired biomechanical functions; (3) the FES strategy was mapped accurately on the altered gait kinematics providing a maximal synchronization between patient's volitional gait and stimulation patterns. The novel intervention was tested on two chronic stroke patients. They underwent a 4-week intervention consisting of 30-min sessions of FES-supported treadmill walking three times per week. The two patients were characterized by a mild gait disability (walking speed > 0.8 m/s) at baseline. However, before treatment both patients presented only three independent muscle synergies during locomotion, resembling two different gait abnormalities. After treatment, the number of extracted synergies became four and they increased their resemblance with the physiological muscle synergies, which indicated a general improvement in muscle coordination. The originally merged synergies seemed to regain their distinct role in locomotion control. The treatment benefits were more evident for one patient, who achieved a clinically important change

Alexithymia is related to differences in gray matter volume: a voxel-based morphometry study.

PubMed

Ihme, Klas; Dannlowski, Udo; Lichev, Vladimir; Stuhrmann, Anja; Grotegerd, Dominik; Rosenberg, Nicole; Kugel, Harald; Heindel, Walter; Arolt, Volker; Kersting, Anette; Suslow, Thomas

2013-01-23

Alexithymia has been characterized as the inability to identify and describe feelings. Functional imaging studies have revealed that alexithymia is linked to reactivity changes in emotion- and face-processing-relevant brain areas. In this respect, anterior cingulate cortex (ACC), amygdala, anterior insula and fusiform gyrus (FFG) have been consistently reported. However, it remains to be clarified whether alexithymia is also associated with structural differences. Voxel-based morphometry on T1-weighted magnetic resonance images was used to investigate gray matter volume in 17 high alexithymics (HA) and 17 gender-matched low alexithymics (LA), which were selected from a sample of 161 healthy volunteers on basis of the 20-item Toronto Alexithymia Scale. Data were analyzed as statistic parametric maps for the comparisons LA>HA and HA>LA in a priori determined regions of interests (ROIs), i.e., ACC, amygdala, anterior insula and FFG. Moreover, an exploratory whole brain analysis was accomplished. For the contrast LA>HA, significant clusters were detected in the ACC, left amygdala and left anterior insula. Additionally, the whole brain analysis revealed volume differences in the left middle temporal gyrus. No significant differences were found for the comparison HA>LA. Our findings suggest that high compared to low alexithymics show less gray matter volume in several emotion-relevant brain areas. These structural differences might contribute to the functional alterations found in previous imaging studies in alexithymia. Copyright © 2012 Elsevier B.V. All rights reserved.

A randomized trial to measure the impact of a community-based cognitive training intervention on balance and gait in cognitively intact Black older adults.

PubMed

Smith-Ray, Renae L; Makowski-Woidan, Beth; Hughes, Susan L

2014-10-01

Fall prevention is important for maintaining mobility and independence into old age. Approaches for reducing falls include exercise, tai chi, and home modifications; however, causes of falling are multifactorial and include not just physical but cognitive factors. Cognitive decline occurs with age, but older adults with the greatest declines in executive function experience more falls. The purpose of this study was twofold: to demonstrate the feasibility of a community-based cognitive training program for cognitively intact Black older adults and to analyze its impact on gait and balance in this population. This pilot study used a pretest/posttest randomized trial design with assignment to an intervention or control group. Participants assigned to the intervention completed a computer-based cognitive training class that met 2 days a week for 60 min over 10 weeks. Classes were held at senior/community centers. Primary outcomes included balance as measured by the Berg Balance Scale (BBS), 10-meter gait speed, and 10-meter gait speed under visuospatial dual-task condition. All measures were assessed at baseline and immediately post-intervention. Participants were community-dwelling Black adults with a mean age of 72.5 and history of falls (N = 45). Compared to controls, intervention participants experienced statistically significant improvements in BBS and gait speed. Mean performance on distracted gait speed also improved more for intervention participants compared to controls. Findings from this pilot randomized trial demonstrate the feasibility of a community-based cognitive training intervention. They provide initial evidence that cognitive training may be an efficacious approach toward improving balance and gait in older adults known to have a history of falls. © 2014 Society for Public Health Education.

Joint kinematic calculation based on clinical direct kinematic versus inverse kinematic gait models.

PubMed

Kainz, H; Modenese, L; Lloyd, D G; Maine, S; Walsh, H P J; Carty, C P

2016-06-14

Most clinical gait laboratories use the conventional gait analysis model. This model uses a computational method called Direct Kinematics (DK) to calculate joint kinematics. In contrast, musculoskeletal modelling approaches use Inverse Kinematics (IK) to obtain joint angles. IK allows additional analysis (e.g. muscle-tendon length estimates), which may provide valuable information for clinical decision-making in people with movement disorders. The twofold aims of the current study were: (1) to compare joint kinematics obtained by a clinical DK model (Vicon Plug-in-Gait) with those produced by a widely used IK model (available with the OpenSim distribution), and (2) to evaluate the difference in joint kinematics that can be solely attributed to the different computational methods (DK versus IK), anatomical models and marker sets by using MRI based models. Eight children with cerebral palsy were recruited and presented for gait and MRI data collection sessions. Differences in joint kinematics up to 13° were found between the Plug-in-Gait and the gait 2392 OpenSim model. The majority of these differences (94.4%) were attributed to differences in the anatomical models, which included different anatomical segment frames and joint constraints. Different computational methods (DK versus IK) were responsible for only 2.7% of the differences. We recommend using the same anatomical model for kinematic and musculoskeletal analysis to ensure consistency between the obtained joint angles and musculoskeletal estimates. Copyright © 2016 Elsevier Ltd. All rights reserved.

Differences in regional brain volume related to the extraversion-introversion dimension--a voxel based morphometry study.

PubMed

Forsman, Lea J; de Manzano, Orjan; Karabanov, Anke; Madison, Guy; Ullén, Fredrik

2012-01-01

Extraverted individuals are sociable, behaviorally active, and happy. We report data from a voxel based morphometry study investigating, for the first time, if regional volume in gray and white matter brain regions is related to extraversion. For both gray and white matter, all correlations between extraversion and regional brain volume were negative, i.e. the regions were larger in introverts. Gray matter correlations were found in regions that included the right prefrontal cortex and the cortex around the right temporo-parietal junction--regions that are known to be involved in behavioral inhibition, introspection, and social-emotional processing, e.g. evaluation of social stimuli and reasoning about the mental states of others. White matter correlations extended from the brainstem to widespread cortical regions, and were largely due to global effects, i.e. a larger total white matter volume in introverts. We speculate that these white matter findings may reflect differences in ascending modulatory projections affecting cortical regions involved in behavioral regulation. Copyright © 2011 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke

PubMed Central

Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-01-01

[Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke. PMID:26157272

Effects of conventional overground gait training and a gait trainer with partial body weight support on spatiotemporal gait parameters of patients after stroke.

PubMed

Park, Byoung-Sun; Kim, Mee-Young; Lee, Lim-Kyu; Yang, Seung-Min; Lee, Won-Deok; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Lee, Jeong-Uk; Kwak, Taek-Yong; Lee, Tae-Hyun; Kim, Ju-Young; Kim, Junghwan

2015-05-01

[Purpose] The purpose of this study was to confirm the effects of both conventional overground gait training (CGT) and a gait trainer with partial body weight support (GTBWS) on spatiotemporal gait parameters of patients with hemiparesis following chronic stroke. [Subjects and Methods] Thirty stroke patients were alternately assigned to one of two treatment groups, and both groups underwent CGT and GTBWS. [Results] The functional ambulation classification on the affected side improved significantly in the CGT and GTBWS groups. Walking speed also improved significantly in both groups. [Conclusion] These results suggest that the GTBWS in company with CGT may be, in part, an effective method of gait training for restoring gait ability in patients after a stroke.

Voxel-based morphometry of auditory and speech-related cortex in stutterers.

PubMed

Beal, Deryk S; Gracco, Vincent L; Lafaille, Sophie J; De Nil, Luc F

2007-08-06

Stutterers demonstrate unique functional neural activation patterns during speech production, including reduced auditory activation, relative to nonstutterers. The extent to which these functional differences are accompanied by abnormal morphology of the brain in stutterers is unclear. This study examined the neuroanatomical differences in speech-related cortex between stutterers and nonstutterers using voxel-based morphometry. Results revealed significant differences in localized grey matter and white matter densities of left and right hemisphere regions involved in auditory processing and speech production.

Brain-volume changes in young and middle-aged smokers: a DARTEL-based voxel-based morphometry study.

PubMed

Peng, Peng; Wang, Zhenchang; Jiang, Tao; Chu, Shuilian; Wang, Shuangkun; Xiao, Dan

2017-09-01

Many studies have reported brain volume changes in smokers. However, the volume differences of grey matter (GM) and white matter (WM) in young and middle-aged male smokers with different lifetime tobacco consumption (pack-years) remain uncertain. To examine the brain volume change, especially whether more pack-years smoking would be associated with smaller gray matter and white matter volume in young and middle-aged male smokers. We used a 3T MR scanner and performed Diffeomorphic anatomical registration through exponentiated lie algebra (DARTEL)-based voxel-based morphometry on 53 long-term male smokers (30.72 ± 4.19 years) and 53 male healthy non-smokers (30.83 ± 5.18 years). We separated smokers to light and heavy smokers by pack-years and compared brain volume between different smoker groups and non-smokers. And then we did analysis of covariance (ANCOVA) between smokers and non-smokers by setting pack-years as covariates. Light and heavy smokers all displayed smaller GM and WM volume than non-smokers and more obviously in heavy smokers. The main smaller areas in light and heavy smokers were superior temporal gyrus, insula, middle occipital gyrus, posterior cingulate, precuneus in GM and posterior cingulate, thalamus and midbrain in WM, in addition, we also observed more pack-years smoking was associated with some certain smaller GM and WM volumes by ANCOVA. Young and middle-aged male smokers had many smaller brain areas than non-smokers. Some of these areas' volume had negative correlation with pack-years, while some had not. These may due to different pathophysiological role of smokings. © 2015 John Wiley & Sons Ltd.

Postprocessing of Voxel-Based Topologies for Additive Manufacturing Using the Computational Geometry Algorithms Library (CGAL)

DTIC Science & Technology

2015-06-01

10-2014 to 00-11-2014 4. TITLE AND SUBTITLE Postprocessing of Voxel-Based Topologies for Additive Manufacturing Using the Computational Geometry...ABSTRACT Postprocessing of 3-dimensional (3-D) topologies that are defined as a set of voxels using the Computational Geometry Algorithms Library (CGAL... computational geometry algorithms, several of which are suited to the task. The work flow described in this report involves first defining a set of

Alterations in white matter volume and its correlation with neuropsychological scales in patients with Alzheimer's disease: a DARTEL-based voxel-based morphometry study.

PubMed

Moon, Chung-Man; Shin, Il-Seon; Jeong, Gwang-Woo

2017-02-01

Background Non-invasive imaging markers can be used to diagnose Alzheimer's disease (AD) in its early stages, but an optimized quantification analysis to measure the brain integrity has been less studied. Purpose To evaluate white matter volume change and its correlation with neuropsychological scales in patients with AD using a diffeomorphic anatomical registration through exponentiated lie algebra (DARTEL)-based voxel-based morphometry (VBM). Material and Methods The 21 participants comprised 11 patients with AD and 10 age-matched healthy controls. High-resolution magnetic resonance imaging (MRI) data were processed by VBM analysis based on DARTEL algorithm. Results The patients showed significant white matter volume reductions in the posterior limb of the internal capsule, cerebral peduncle of the midbrain, and parahippocampal gyrus compared to healthy controls. In correlation analysis, the parahippocampal volume was positively correlated with the Korean-mini mental state examination score in AD. Conclusion This study provides an evidence for localized white matter volume deficits in conjunction with cognitive dysfunction in AD. These findings would be helpful to understand the neuroanatomical mechanisms in AD and to robust the diagnostic accuracy for AD.

A voxel-based mouse for internal dose calculations using Monte Carlo simulations (MCNP).

PubMed

Bitar, A; Lisbona, A; Thedrez, P; Sai Maurel, C; Le Forestier, D; Barbet, J; Bardies, M

2007-02-21

Murine models are useful for targeted radiotherapy pre-clinical experiments. These models can help to assess the potential interest of new radiopharmaceuticals. In this study, we developed a voxel-based mouse for dosimetric estimates. A female nude mouse (30 g) was frozen and cut into slices. High-resolution digital photographs were taken directly on the frozen block after each section. Images were segmented manually. Monoenergetic photon or electron sources were simulated using the MCNP4c2 Monte Carlo code for each source organ, in order to give tables of S-factors (in Gy Bq-1 s-1) for all target organs. Results obtained from monoenergetic particles were then used to generate S-factors for several radionuclides of potential interest in targeted radiotherapy. Thirteen source and 25 target regions were considered in this study. For each source region, 16 photon and 16 electron energies were simulated. Absorbed fractions, specific absorbed fractions and S-factors were calculated for 16 radionuclides of interest for targeted radiotherapy. The results obtained generally agree well with data published previously. For electron energies ranging from 0.1 to 2.5 MeV, the self-absorbed fraction varies from 0.98 to 0.376 for the liver, and from 0.89 to 0.04 for the thyroid. Electrons cannot be considered as 'non-penetrating' radiation for energies above 0.5 MeV for mouse organs. This observation can be generalized to radionuclides: for example, the beta self-absorbed fraction for the thyroid was 0.616 for I-131; absorbed fractions for Y-90 for left kidney-to-left kidney and for left kidney-to-spleen were 0.486 and 0.058, respectively. Our voxel-based mouse allowed us to generate a dosimetric database for use in preclinical targeted radiotherapy experiments.

The overlapping brain region accounting for the relationship between procrastination and impulsivity: A voxel-based morphometry study.

PubMed

Liu, Peiwei; Feng, Tingyong

2017-09-30

Procrastination is a prevalent problematic behavior that brings serious consequences, such as lower levels of health, wealth, and well-being. Previous research has verified that impulsivity is one of the traits most strongly correlated with procrastination. However, little is known about why there is a tight behavioral relationship between them. To address this question, we used voxel-based morphometry (VBM) to explore the common neural substrates between procrastination and impulsivity. In line with previous findings, the behavioral results showed a strong behavioral correlation between procrastination and impulsivity. Neuroimaging results showed impulsivity and procrastination shared the common neurobiological underpinnings in the dorsolateral prefrontal cortex (DLPFC) based on the data from 85 participants (sample 1). Furthermore, the mediation analysis revealed that impulsivity mediated the impact of gray matter (GM) volumes of this overlapping region in the DLPFC on procrastination on another independent 84 participants' data (sample 2). In conclusion, the overlapping brain region in the DLPFC would be responsible for the close relationship between procrastination and impulsivity. As a whole, the present study extends our knowledge on procrastination, and provides a novel perspective to explain the tight impulsivity - procrastination relationship. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Spatial parameters of walking gait and footedness.

PubMed

Zverev, Y P

2006-01-01

The present study was undertaken to assess whether footedness has effects on selected spatial and angular parameters of able-bodied gait by evaluating footprints of young adults. A total of 112 males and 93 females were selected from among students and staff members of the University of Malawi using a simple random sampling method. Footedness of subjects was assessed by the Waterloo Footedness Questionnaire Revised. Gait at natural speed was recorded using the footprint method. The following spatial parameters of gait were derived from the inked footprint sequences of subjects: step and stride lengths, gait angle and base of gait. The anthropometric measurements taken were weight, height, leg and foot length, foot breadth, shoulder width, and hip and waist circumferences. The prevalence of right-, left- and mix-footedness in the whole sample of young Malawian adults was 81%, 8.3% and 10.7%, respectively. One-way analysis of variance did not reveal a statistically significant difference between footedness categories in the mean values of anthropometric measurements (p > 0.05 for all variables). Gender differences in step and stride length values were not statistically significant. Correction of these variables for stature did not change the trend. Males had significantly broader steps than females. Normalized values of base of gait had similar gender difference. The group means of step length and normalized step length of the right and left feet were similar, for males and females. There was a significant side difference in the gait angle in both gender groups of volunteers with higher mean values on the left side compared to the right one (t = 2.64, p < 0.05 for males, and t = 2.78, p < 0.05 for females). One-way analysis of variance did not demonstrate significant difference between footedness categories in the mean values of step length, gait angle, bilateral differences in step length and gait angle, stride length, gait base and normalized gait variables of male

Balance and Gait Impairment: Sensor-Based Assessment for Patients With Peripheral Neuropathy.

PubMed

Campbell, Grace; Skubic, Marjorie A

2018-06-01

Individuals with peripheral neuropathy (PN) frequently experience balance and gait impairments that can lead to poor physical function, falls, and injury. Nurses are aware that patients with cancer experience balance and gait impairments but are unsure of optimal assessment and management strategies. This article reviews options for balance and gait assessment for patients diagnosed with cancer experiencing PN, describes advantages and limitations of the various options, and highlights innovative, clinically feasible technologies to improve clinical assessment and management. The literature was reviewed to identify and assess the gold standard quantitative measures for assessing balance and gait. Gold standard quantitative measures are burdensome for patients and not often used in clinical practice. Sensor-based technologies improve balance and gait assessment options by calculating precise impairment measures during performance of simple clinical tests at the point of care.

Theory of mind and frontal lobe pathology in schizophrenia: a voxel-based morphometry study.

PubMed

Hirao, Kazuyuki; Miyata, Jun; Fujiwara, Hironobu; Yamada, Makiko; Namiki, Chihiro; Shimizu, Mitsuaki; Sawamoto, Nobukatsu; Fukuyama, Hidenao; Hayashi, Takuji; Murai, Toshiya

2008-10-01

Impaired ability to infer the mental states of others (theory of mind; ToM) is considered to be a key contributor to the poor social functioning of patients with schizophrenia. Although neuroimaging and lesion studies have provided empirical evidence for the neural basis of ToM ability, including the involvement of several prefrontal and temporal structures, the association between pathology of these structures and ToM impairment in schizophrenia patients is less well understood. To address this issue, we investigated structural brain abnormalities and ToM impairment in patients with schizophrenia, and examined the relationship between them. Twenty schizophrenia patients and 20 age-, sex- and education-matched healthy participants underwent magnetic resonance imaging (MRI) and were examined for ToM ability based on the revised version of the "Reading the Mind in the Eyes" (or Eyes) test [Baron-Cohen, S., Wheelwright, S., Hill, J., Raste, Y., Plumb, I., 2001. The 'Reading the Mind in the Eyes' test revised version: A study with normal adults, and adults with Asperger syndrome or high-functioning autism. J. Child Psychol. Psychiatry 42, 241-251]. Voxel-based morphometry (VBM) was performed to investigate regional brain alterations. Relative to normal controls, schizophrenia patients exhibited gray matter reductions in the dorsomedial prefrontal cortex (DMPFC), left ventrolateral prefrontal cortex (VLPFC), ventromedial prefrontal cortex (VMPFC), anterior cingulate cortex (ACC), right superior temporal gyrus (STG) and right insula. The patients performed poorly on the Eyes test. Importantly, poor performance on the Eyes test was found to be associated with gray matter reduction in the left VLPFC in the patient group. These results suggest that prefrontal cortical reduction, especially in the left VLPFC, is a key pathology underlying the difficulties faced by schizophrenia patients in inferring the mental states of others.

Gait Recognition Using Wearable Motion Recording Sensors

NASA Astrophysics Data System (ADS)

Gafurov, Davrondzhon; Snekkenes, Einar

2009-12-01

This paper presents an alternative approach, where gait is collected by the sensors attached to the person's body. Such wearable sensors record motion (e.g. acceleration) of the body parts during walking. The recorded motion signals are then investigated for person recognition purposes. We analyzed acceleration signals from the foot, hip, pocket and arm. Applying various methods, the best EER obtained for foot-, pocket-, arm- and hip- based user authentication were 5%, 7%, 10% and 13%, respectively. Furthermore, we present the results of our analysis on security assessment of gait. Studying gait-based user authentication (in case of hip motion) under three attack scenarios, we revealed that a minimal effort mimicking does not help to improve the acceptance chances of impostors. However, impostors who know their closest person in the database or the genders of the users can be a threat to gait-based authentication. We also provide some new insights toward the uniqueness of gait in case of foot motion. In particular, we revealed the following: a sideway motion of the foot provides the most discrimination, compared to an up-down or forward-backward directions; and different segments of the gait cycle provide different level of discrimination.

Gait Speed rather than Dynapenia Is a Simple Indicator for Complex Care Needs: A Cross-sectional Study Using Minimum Data Set.

PubMed

Huang, Tzu-Ya; Liang, Chih-Kuang; Shen, Hsiu-Chu; Chen, Hon-I; Liao, Mei-Chen; Chou, Ming-Yueh; Lin, Yu-Te; Chen, Liang-Kung

2017-08-21

The impact of dynapenia on the complexity of care for residents of long-term care facilities (LTCF) remains unclear. The present study evaluated associations between dynapenia, care problems and care complexity in 504 residents of Veterans Care Homes (VCHs) in Taiwan. Subjects with dynapenia, defined as low muscle strength (handgrip strength <26 kg), were older adults with lower body mass index (BMI), slow gait speed, and higher numbers of Resident Assessment Protocol (RAP) triggers. After adjusting for age, education, BMI, and Charlson's comorbidity index (CCI), only age, education, BMI and gait speed were independently associated with higher numbers of RAP triggers, but not dynapenia or handgrip strength (kg). Dividing subjects into groups based on quartiles of gait speed, those with gait speed ≤0.803 m/s were significantly associated with higher complexity of care needs (defined as ≥4 RAP triggers) compared to the reference group (gait speed >1 m/s). Significantly slow gait speed was associated with RAP triggers, including cognitive loss, poor communication ability, rehabilitation needs, urinary incontinence, depressed mood, falls, pressure ulcers, and use of psychotropic drugs. In conclusion, slow gait speed rather than dynapenia is a simple indicator for higher complexity of care needs of older male LTCF residents.

Self-perceived gait stability modulates the effect of daily life gait quality on prospective falls in older adults.

PubMed

Weijer, R H A; Hoozemans, M J M; van Dieën, J H; Pijnappels, M

2018-05-01

Quality of gait during daily life activities and perceived gait stability are both independent risk factors for future falls in older adults. We investigated whether perceived gait stability modulates the association between gait quality and falling in older adults. In this prospective cohort study, we used one-week daily-life trunk acceleration data of 272 adults over 65 years of age. Sample entropy (SE) of the 3D acceleration signals was calculated to quantify daily life gait quality. To quantify perceived gait stability, the level of concern about falling was assessed using the Falls Efficacy Scale international (FES-I) questionnaire and step length, estimated from the accelerometer data. A fall calendar was used to record fall incidence during a six-month follow up period. Logistic regression analyses were performed to study the association between falling and SE, step length or FES-I score, and their interactions. High (i.e., poor) SE in vertical direction was significantly associated with falling. FES-I scores significantly modulated this association, whereas step length did not. Subgroup analyses based on FES-I scores showed that high SE in the vertical direction was a risk factor for falls only in older adults who had a high (i.e. poor) FES-I score. In conclusion, perceived gait stability modulates the association between gait quality and falls in older adults such that an association between gait quality and falling is only present when perceived gait stability is poor. The results of the present study indicate that the effectiveness of interventions for fall prevention, aimed at improving gait quality, may be affected by a modulating effect of perceived gait stability. Results indicate that interventions to reduce falls in older adults might sort most effectiveness in populations with both a poor physiological and psychological status. Copyright © 2018 Elsevier B.V. All rights reserved.

A multi-channel biomimetic neuroprosthesis to support treadmill gait training in stroke patients.

PubMed

Chia, Noelia; Ambrosini, Emilia; Baccinelli, Walter; Nardone, Antonio; Monticone, Marco; Ferrigno, Giancarlo; Pedrocchi, Alessandra; Ferrante, Simona

2015-01-01

This study presents an innovative multi-channel neuroprosthesis that induces a biomimetic activation of the main lower-limb muscles during treadmill gait training to be used in the rehabilitation of stroke patients. The electrostimulation strategy replicates the physiological muscle synergies used by healthy subjects to walk on a treadmill at their self-selected speed. This strategy is mapped to the current gait sub-phases, which are identified in real time by a custom algorithm. This algorithm divides the gait cycle into six sub-phases, based on two inertial sensors placed laterally on the shanks. Therefore, the pre-defined stimulation profiles are expanded or stretched based on the actual gait pattern of each single subject. A preliminary experimental protocol, involving 10 healthy volunteers, was carried out to extract the muscle synergies and validate the gait-detection algorithm, which were afterwards used in the development of the neuroprosthesis. The feasibility of the neuroprosthesis was tested on one healthy subject who simulated different gait patterns, and a chronic stroke patient. The results showed the correct functioning of the system. A pilot study of the neurorehabilitation treatment for stroke patients is currently being carried out.

Grey matter, an endophenotype for schizophrenia? A voxel-based morphometry study in siblings of patients with schizophrenia

PubMed Central

van der Velde, Jorien; Gromann, Paula M.; Swart, Marte; de Haan, Lieuwe; Wiersma, Durk; Bruggeman, Richard; Krabbendam, Lydia; Aleman, André

2015-01-01

Background Grey matter, both volume and concentration, has been proposed as an endophenotype for schizophrenia given a number of reports of grey matter abnormalities in relatives of patients with schizophrenia. However, previous studies on grey matter abnormalities in relatives have produced inconsistent results. The aim of the present study was to examine grey matter differences between controls and siblings of patients with schizophrenia and to examine whether the age, genetic loading or subclinical psychotic symptoms of selected individuals could explain the previously reported inconsistencies. Methods We compared the grey matter volume and grey matter concentration of healthy siblings of patients with schizophrenia and healthy controls matched for age, sex and education using voxel-based morphometry (VBM). Furthermore, we selected subsamples based on age (< 30 yr), genetic loading and subclinical psychotic symptoms to examine whether this would lead to different results. Results We included 89 siblings and 69 controls in our study. The results showed that siblings and controls did not differ significantly on grey matter volume or concentration. Furthermore, specifically selecting participants based on age, genetic loading or subclinical psychotic symptoms did not alter these findings. Limitations The main limitation was that subdividing the sample resulted in smaller samples for the subanalyses. Furthermore, we used MRI data from 2 different scanner sites. Conclusion These results indicate that grey matter measured through VBM might not be a suitable endophenotype for schizophrenia. PMID:25768029

Apolipoprotein E4 Allele and Gait Performance in Mild Cognitive Impairment: Results From the Gait and Brain Study.

PubMed

Sakurai, Ryota; Montero-Odasso, Manuel

2017-11-09

The apolipoprotein E polymorphism ε4 allele (ApoE4) and gait impairment are both known risk factors for developing cognitive decline and dementia. However, it is unclear the interrelationship between these factors, particularly among older adults with mild cognitive impairment (MCI) who are considered as prodromal for Alzheimer's disease. This study aimed to determine whether ApoE4 carrier individuals with MCI may experience greater impairment in gait performance. Fifty-six older adults with MCI from the "Gait and Brain Study" who were identified as either ApoE4 carriers (n = 20) or non-ApoE4 carriers (n = 36) with 1 year of follow-up were included. Gait variability, the main outcome variable, was assessed as stride time variability with an electronic walkway. Additional gait variables and cognitive performance (mini-mental state examination [MMSE] and Montreal Cognitive Assessment [MoCA]) were also recorded. Covariates included age, sex, education level, body mass index, and number of comorbidities. Baseline characteristics were similar for both groups. Repeated measures analysis of covariance showed that gait stride time and stride length variabilities significantly increased in ApoE4 carriers but was maintained in the non-ApoE4 carriers. Similarly, ApoE4 carriers showed greater decrease in MMSE score at follow-up. In this sample of older adults with MCI, the presence of at least one copy of ApoE4 was associated with the development of both increased gait variability and cognitive decline during 1 year of follow-up. ApoE4 genotype might be considered as a potential mediator of decline in mobility function in MCI; future studies with larger samples are needed to confirm our preliminary findings. © The Author 2017. 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.

Reliability and validity of a smartphone-based assessment of gait parameters across walking speed and smartphone locations: Body, bag, belt, hand, and pocket.

PubMed

Silsupadol, Patima; Teja, Kunlanan; Lugade, Vipul

2017-10-01

The assessment of spatiotemporal gait parameters is a useful clinical indicator of health status. Unfortunately, most assessment tools require controlled laboratory environments which can be expensive and time consuming. As smartphones with embedded sensors are becoming ubiquitous, this technology can provide a cost-effective, easily deployable method for assessing gait. Therefore, the purpose of this study was to assess the reliability and validity of a smartphone-based accelerometer in quantifying spatiotemporal gait parameters when attached to the body or in a bag, belt, hand, and pocket. Thirty-four healthy adults were asked to walk at self-selected comfortable, slow, and fast speeds over a 10-m walkway while carrying a smartphone. Step length, step time, gait velocity, and cadence were computed from smartphone-based accelerometers and validated with GAITRite. Across all walking speeds, smartphone data had excellent reliability (ICC 2,1 ≥0.90) for the body and belt locations, with bag, hand, and pocket locations having good to excellent reliability (ICC 2,1 ≥0.69). Correlations between the smartphone-based and GAITRite-based systems were very high for the body (r=0.89, 0.98, 0.96, and 0.87 for step length, step time, gait velocity, and cadence, respectively). Similarly, Bland-Altman analysis demonstrated that the bias approached zero, particularly in the body, bag, and belt conditions under comfortable and fast speeds. Thus, smartphone-based assessments of gait are most valid when placed on the body, in a bag, or on a belt. The use of a smartphone to assess gait can provide relevant data to clinicians without encumbering the user and allow for data collection in the free-living environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Identifying Voxels at Risk for Progression in Glioblastoma Based on Dosimetry, Physiologic and Metabolic MRI.

PubMed

Anwar, Mekhail; Molinaro, Annette M; Morin, Olivier; Chang, Susan M; Haas-Kogan, Daphne A; Nelson, Sarah J; Lupo, Janine M

2017-09-01

Despite the longstanding role of radiation in cancer treatment and the presence of advanced, high-resolution imaging techniques, delineation of voxels at-risk for progression remains purely a geometric expansion of anatomic images, missing subclinical disease at risk for recurrence while treating potentially uninvolved tissue and increasing toxicity. This remains despite the modern ability to precisely shape radiation fields. A striking example of this is the treatment of glioblastoma, a highly infiltrative tumor that may benefit from accurate identification of subclinical disease. In this study, we hypothesize that parameters from physiologic and metabolic magnetic resonance imaging (MRI) at diagnosis could predict the likelihood of voxel progression at radiographic recurrence in glioblastoma by identifying voxel characteristics that indicate subclinical disease. Integrating dosimetry can reveal its effect on voxel outcome, enabling risk-adapted voxel dosing. As a system example, 24 patients with glioblastoma treated with radiotherapy, temozolomide and an anti-angiogenic agent were analyzed. Pretreatment median apparent diffusion coefficient (ADC), fractional anisotropy (FA), relative cerebral blood volume (rCBV), vessel leakage (percentage recovery), choline-to-NAA index (CNI) and dose of voxels in the T2 nonenhancing lesion (NEL), T1 post-contrast enhancing lesion (CEL) or normal-appearing volume (NAV) of brain, were calculated for voxels that progressed [NAV→NEL, CEL (N = 8,765)] and compared against those that remained stable [NAV→NAV (N = 98,665)]. Voxels that progressed (NAV→NEL) had significantly different (P < 0.01) ADC (860), FA (0.36) and CNI (0.67) versus stable voxels (804, 0.43 and 0.05, respectively), indicating increased cell turnover, edema and decreased directionality, consistent with subclinical disease. NAV→CEL voxels were more abnormal (1,014, 0.28, 2.67, respectively) and leakier (percentage recovery = 70). A predictive model

Voxel-Based Neighborhood for Spatial Shape Pattern Classification of Lidar Point Clouds with Supervised Learning

PubMed Central

Plaza-Leiva, Victoria; Gomez-Ruiz, Jose Antonio; Mandow, Anthony; García-Cerezo, Alfonso

2017-01-01

Improving the effectiveness of spatial shape features classification from 3D lidar data is very relevant because it is largely used as a fundamental step towards higher level scene understanding challenges of autonomous vehicles and terrestrial robots. In this sense, computing neighborhood for points in dense scans becomes a costly process for both training and classification. This paper proposes a new general framework for implementing and comparing different supervised learning classifiers with a simple voxel-based neighborhood computation where points in each non-overlapping voxel in a regular grid are assigned to the same class by considering features within a support region defined by the voxel itself. The contribution provides offline training and online classification procedures as well as five alternative feature vector definitions based on principal component analysis for scatter, tubular and planar shapes. Moreover, the feasibility of this approach is evaluated by implementing a neural network (NN) method previously proposed by the authors as well as three other supervised learning classifiers found in scene processing methods: support vector machines (SVM), Gaussian processes (GP), and Gaussian mixture models (GMM). A comparative performance analysis is presented using real point clouds from both natural and urban environments and two different 3D rangefinders (a tilting Hokuyo UTM-30LX and a Riegl). Classification performance metrics and processing time measurements confirm the benefits of the NN classifier and the feasibility of voxel-based neighborhood. PMID:28294963

Voxel-Based Neighborhood for Spatial Shape Pattern Classification of Lidar Point Clouds with Supervised Learning.

PubMed

Plaza-Leiva, Victoria; Gomez-Ruiz, Jose Antonio; Mandow, Anthony; García-Cerezo, Alfonso

2017-03-15

Improving the effectiveness of spatial shape features classification from 3D lidar data is very relevant because it is largely used as a fundamental step towards higher level scene understanding challenges of autonomous vehicles and terrestrial robots. In this sense, computing neighborhood for points in dense scans becomes a costly process for both training and classification. This paper proposes a new general framework for implementing and comparing different supervised learning classifiers with a simple voxel-based neighborhood computation where points in each non-overlapping voxel in a regular grid are assigned to the same class by considering features within a support region defined by the voxel itself. The contribution provides offline training and online classification procedures as well as five alternative feature vector definitions based on principal component analysis for scatter, tubular and planar shapes. Moreover, the feasibility of this approach is evaluated by implementing a neural network (NN) method previously proposed by the authors as well as three other supervised learning classifiers found in scene processing methods: support vector machines (SVM), Gaussian processes (GP), and Gaussian mixture models (GMM). A comparative performance analysis is presented using real point clouds from both natural and urban environments and two different 3D rangefinders (a tilting Hokuyo UTM-30LX and a Riegl). Classification performance metrics and processing time measurements confirm the benefits of the NN classifier and the feasibility of voxel-based neighborhood.

Energy Expenditure of Trotting Gait Under Different Gait Parameters

NASA Astrophysics Data System (ADS)

Chen, Xian-Bao; Gao, Feng

2017-07-01

Robots driven by batteries are clean, quiet, and can work indoors or in space. However, the battery endurance is a great problem. A new gait parameter design energy saving strategy to extend the working hours of the quadruped robot is proposed. A dynamic model of the robot is established to estimate and analyze the energy expenditures during trotting. Given a trotting speed, optimal stride frequency and stride length can minimize the energy expenditure. However, the relationship between the speed and the optimal gait parameters is nonlinear, which is difficult for practical application. Therefore, a simplified gait parameter design method for energy saving is proposed. A critical trotting speed of the quadruped robot is found and can be used to decide the gait parameters. When the robot is travelling lower than this speed, it is better to keep a constant stride length and change the cycle period. When the robot is travelling higher than this speed, it is better to keep a constant cycle period and change the stride length. Simulations and experiments on the quadruped robot show that by using the proposed gait parameter design approach, the energy expenditure can be reduced by about 54% compared with the 100 mm stride length under 500 mm/s speed. In general, an energy expenditure model based on the gait parameter of the quadruped robot is built and the trotting gait parameters design approach for energy saving is proposed.

Whole-brain voxel-based morphometry in Kallmann syndrome associated with mirror movements.

PubMed

Koenigkam-Santos, M; Santos, A C; Borduqui, T; Versiani, B R; Hallak, J E C; Crippa, J A S; Castro, M

2008-10-01

There are 2 main hypotheses concerning the cause of mirror movements (MM) in Kallmann syndrome (KS): abnormal development of the primary motor system, involving the ipsilateral corticospinal tract; and lack of contralateral motor cortex inhibitory mechanisms, mainly through the corpus callosum. The purpose of our study was to determine white and gray matter volume changes in a KS population by using optimized voxel-based morphometry (VBM) and to investigate the relationship between the abnormalities and the presence of MM, addressing the 2 mentioned hypotheses. T1-weighted volumetric images from 21 patients with KS and 16 matched control subjects were analyzed with optimized VBM. Images were segmented and spatially normalized, and these deformation parameters were then applied to the original images before the second segmentation. Patients were divided into groups with and without MM, and a t test statistic was then applied on a voxel-by-voxel basis between the groups and controls to evaluate significant differences. When considering our hypothesis a priori, we found that 2 areas of increased gray matter volume, in the left primary motor and sensorimotor cortex, were demonstrated only in patients with MM, when compared with healthy controls. Regarding white matter alterations, no areas of altered volume involving the corpus callosum or the projection of the corticospinal tract were demonstrated. The VBM study did not show significant white matter changes in patients with KS but showed gray matter alterations in keeping with a hypertrophic response to a deficient pyramidal decussation in patients with MM. In addition, gray matter alterations were observed in patients without MM, which can represent more complex mechanisms determining the presence or absence of this symptom.

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

A voxel-based lesion study on facial emotion recognition after penetrating brain injury

PubMed Central

Dal Monte, Olga; Solomon, Jeffrey M.; Schintu, Selene; Knutson, Kristine M.; Strenziok, Maren; Pardini, Matteo; Leopold, Anne; Raymont, Vanessa; Grafman, Jordan

2013-01-01

The ability to read emotions in the face of another person is an important social skill that can be impaired in subjects with traumatic brain injury (TBI). To determine the brain regions that modulate facial emotion recognition, we conducted a whole-brain analysis using a well-validated facial emotion recognition task and voxel-based lesion symptom mapping (VLSM) in a large sample of patients with focal penetrating TBIs (pTBIs). Our results revealed that individuals with pTBI performed significantly worse than normal controls in recognizing unpleasant emotions. VLSM mapping results showed that impairment in facial emotion recognition was due to damage in a bilateral fronto-temporo-limbic network, including medial prefrontal cortex (PFC), anterior cingulate cortex, left insula and temporal areas. Beside those common areas, damage to the bilateral and anterior regions of PFC led to impairment in recognizing unpleasant emotions, whereas bilateral posterior PFC and left temporal areas led to impairment in recognizing pleasant emotions. Our findings add empirical evidence that the ability to read pleasant and unpleasant emotions in other people's faces is a complex process involving not only a common network that includes bilateral fronto-temporo-limbic lobes, but also other regions depending on emotional valence. PMID:22496440

An electromechanical gait trainer for restoration of gait in hemiparetic stroke patients: preliminary results.

PubMed

Hesse, S; Werner, C; Uhlenbrock, D; von Frankenberg, S; Bardeleben, A; Brandl-Hesse, B

2001-01-01

Modern concepts of gait rehabilitation after stroke favor a task-specific repetitive approach. In practice, the required physical effort of the therapists limits the realization of this approach. Therefore, a mechanized gait trainer enabling nonambulatory patients to have the repetitive practice of a gait-like movement without overstraining therapists was constructed. This preliminary study investigated whether an additional 4-week daily therapy on the gait trainer could improve gait ability in 14 chronic wheelchair-bound hemiparetic subjects. The 4 weeks of physiotherapy and gait-trainer therapy resulted in a relevant improvement of gait ability in all subjects. Velocity, cadence, and stride length improved significantly (p < 0.01). The kinesiologic electromyogram of selected lower-limb muscles revealed a more physiologic pattern. The confounding influence of spontaneous recovery, the lack of a control group, and the double amount of therapy limit the clinical relevance of this study. Nevertheless, the gait trainer seems feasible as an adjunctive tool in gait rehabilitation after stroke; further studies are needed.

Real-Time Gait Event Detection Based on Kinematic Data Coupled to a Biomechanical Model.

PubMed

Lambrecht, Stefan; Harutyunyan, Anna; Tanghe, Kevin; Afschrift, Maarten; De Schutter, Joris; Jonkers, Ilse

2017-03-24

Real-time detection of multiple stance events, more specifically initial contact (IC), foot flat (FF), heel off (HO), and toe off (TO), could greatly benefit neurorobotic (NR) and neuroprosthetic (NP) control. Three real-time threshold-based algorithms have been developed, detecting the aforementioned events based on kinematic data in combination with a biomechanical model. Data from seven subjects walking at three speeds on an instrumented treadmill were used to validate the presented algorithms, accumulating to a total of 558 steps. The reference for the gait events was obtained using marker and force plate data. All algorithms had excellent precision and no false positives were observed. Timing delays of the presented algorithms were similar to current state-of-the-art algorithms for the detection of IC and TO, whereas smaller delays were achieved for the detection of FF. Our results indicate that, based on their high precision and low delays, these algorithms can be used for the control of an NR/NP, with the exception of the HO event. Kinematic data is used in most NR/NP control schemes and is thus available at no additional cost, resulting in a minimal computational burden. The presented methods can also be applied for screening pathological gait or gait analysis in general in/outside of the laboratory.

Gray matter correlates of creative potential: A latent variable voxel-based morphometry study

PubMed Central

Jauk, Emanuel; Neubauer, Aljoscha C.; Dunst, Beate; Fink, Andreas; Benedek, Mathias

2015-01-01

There is increasing research interest in the structural and functional brain correlates underlying creative potential. Recent investigations found that interindividual differences in creative potential relate to volumetric differences in brain regions belonging to the default mode network, such as the precuneus. Yet, the complex interplay between creative potential, intelligence, and personality traits and their respective neural bases is still under debate. We investigated regional gray matter volume (rGMV) differences that can be associated with creative potential in a heterogeneous sample of N = 135 individuals using voxel-based morphometry (VBM). By means of latent variable modeling and consideration of recent psychometric advancements in creativity research, we sought to disentangle the effects of ideational originality and fluency as two independent indicators of creative potential. Intelligence and openness to experience were considered as common covariates of creative potential. The results confirmed and extended previous research: rGMV in the precuneus was associated with ideational originality, but not with ideational fluency. In addition, we found ideational originality to be correlated with rGMV in the caudate nucleus. The results indicate that the ability to produce original ideas is tied to default-mode as well as dopaminergic structures. These structural brain correlates of ideational originality were apparent throughout the whole range of intellectual ability and thus not moderated by intelligence. In contrast, structural correlates of ideational fluency, a quantitative marker of creative potential, were observed only in lower intelligent individuals in the cuneus/lingual gyrus. PMID:25676914

Voxel-based lesion-symptom mapping of stroke lesions underlying somatosensory deficits

PubMed Central

Meyer, Sarah; Kessner, Simon S.; Cheng, Bastian; Bönstrup, Marlene; Schulz, Robert; Hummel, Friedhelm C.; De Bruyn, Nele; Peeters, Andre; Van Pesch, Vincent; Duprez, Thierry; Sunaert, Stefan; Schrooten, Maarten; Feys, Hilde; Gerloff, Christian; Thomalla, Götz; Thijs, Vincent; Verheyden, Geert

2015-01-01

The aim of this study was to investigate the relationship between stroke lesion location and the resulting somatosensory deficit. We studied exteroceptive and proprioceptive somatosensory symptoms and stroke lesions in 38 patients with first-ever acute stroke. The Erasmus modified Nottingham Sensory Assessment was used to clinically evaluate somatosensory functioning in the arm and hand within the first week after stroke onset. Additionally, more objective measures such as the perceptual threshold of touch and somatosensory evoked potentials were recorded. Non-parametric voxel-based lesion-symptom mapping was performed to investigate lesion contribution to different somatosensory deficits in the upper limb. Additionally, structural connectivity of brain areas that demonstrated the strongest association with somatosensory symptoms was determined, using probabilistic fiber tracking based on diffusion tensor imaging data from a healthy age-matched sample. Voxels with a significant association to somatosensory deficits were clustered in two core brain regions: the central parietal white matter, also referred to as the sensory component of the superior thalamic radiation, and the parietal operculum close to the insular cortex, representing the secondary somatosensory cortex. Our objective recordings confirmed findings from clinical assessments. Probabilistic tracking connected the first region to thalamus, internal capsule, brain stem, postcentral gyrus, cerebellum, and frontal pathways, while the second region demonstrated structural connections to thalamus, insular and primary somatosensory cortex. This study reveals that stroke lesions in the sensory fibers of the superior thalamocortical radiation and the parietal operculum are significantly associated with multiple exteroceptive and proprioceptive deficits in the arm and hand. PMID:26900565

Accelerometer-based step initiation control for gait-assist neuroprostheses.

PubMed

Foglyano, Kevin M; Schnellenberger, John R; Kobetic, Rudi; Lombardo, Lisa; Pinault, Gilles; Selkirk, Stephen; Makowski, Nathaniel S; Triolo, Ronald J

2016-01-01

Electrical activation of paralyzed musculature can generate or augment joint movements required for walking after central nervous system trauma. Proper timing of stimulation relative to residual volitional control is critical to usefully affecting ambulation. This study evaluates three-dimensional accelerometers and customized algorithms to detect the intent to step from voluntary movements to trigger stimulation during walking in individuals with significantly different etiologies, mobility limitations, manual dexterities, and walking aids. Three individuals with poststroke hemiplegia or partial spinal cord injury exhibiting varying gait deficits were implanted with multichannel pulse generators to provide joint motions at the hip, knee, and ankle. An accelerometer integrated into the external control unit was used to detect heel strike or walker movement, and wireless accelerometers were used to detect crutch strike. Algorithms were developed for each sensor location to detect intent to step to progress through individualized stimulation patterns. Testing these algorithms produced detection accuracies of at least 90% on both level ground and uneven terrain. All participants use their accelerometer-triggered implanted gait systems in the community; the validation/system testing was completed in the hospital. The results demonstrated that safe, reliable, and convenient accelerometer-based step initiation can be achieved regardless of specific gait deficits, manual dexterities, and walking aids.

Increased Grey Matter Associated with Long-Term Sahaja Yoga Meditation: A Voxel-Based Morphometry Study.

PubMed

Hernández, Sergio Elías; Suero, José; Barros, Alfonso; González-Mora, José Luis; Rubia, Katya

2016-01-01

To investigate regional differences in grey matter volume associated with the practice of Sahaja Yoga Meditation. Twenty three experienced practitioners of Sahaja Yoga Meditation and twenty three non-meditators matched on age, gender and education level, were scanned using structural Magnetic Resonance Imaging and their grey matter volume were compared using Voxel-Based Morphometry. Grey matter volume was larger in meditators relative to non-meditators across the whole brain. In addition, grey matter volume was larger in several predominantly right hemispheric regions: in insula, ventromedial orbitofrontal cortex, inferior temporal and parietal cortices as well as in left ventrolateral prefrontal cortex and left insula. No areas with larger grey matter volume were found in non-meditators relative to meditators. The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger grey matter volume overall, and with regional enlargement in several right hemispheric cortical and subcortical brain regions that are associated with sustained attention, self-control, compassion and interoceptive perception. The increased grey matter volume in these attention and self-control mediating regions suggests use-dependent enlargement with regular practice of this meditation.

Increased Grey Matter Associated with Long-Term Sahaja Yoga Meditation: A Voxel-Based Morphometry Study

PubMed Central

Hernández, Sergio Elías; Suero, José; Barros, Alfonso; González-Mora, José Luis; Rubia, Katya

2016-01-01

Objectives To investigate regional differences in grey matter volume associated with the practice of Sahaja Yoga Meditation. Design Twenty three experienced practitioners of Sahaja Yoga Meditation and twenty three non-meditators matched on age, gender and education level, were scanned using structural Magnetic Resonance Imaging and their grey matter volume were compared using Voxel-Based Morphometry. Results Grey matter volume was larger in meditators relative to non-meditators across the whole brain. In addition, grey matter volume was larger in several predominantly right hemispheric regions: in insula, ventromedial orbitofrontal cortex, inferior temporal and parietal cortices as well as in left ventrolateral prefrontal cortex and left insula. No areas with larger grey matter volume were found in non-meditators relative to meditators. Conclusions The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger grey matter volume overall, and with regional enlargement in several right hemispheric cortical and subcortical brain regions that are associated with sustained attention, self-control, compassion and interoceptive perception. The increased grey matter volume in these attention and self-control mediating regions suggests use-dependent enlargement with regular practice of this meditation. PMID:26938433

Change in gait after high tibial osteotomy: A systematic review and meta-analysis.

PubMed

Lee, Seung Hoon; Lee, O-Sung; Teo, Seow Hui; Lee, Yong Seuk

2017-09-01

We conducted a meta-analysis to analyze how high tibial osteotomy (HTO) changes gait and focused on the following questions: (1) How does HTO change basic gait variables? (2) How does HTO change the gait variables in the knee joint? Twelve articles were included in the final analysis. A total of 383 knees was evaluated. There were 237 open wedge (OW) and 143 closed wedge (CW) HTOs. There were 4 level II studies and 8 level III studies. All studies included gait analysis and compared pre- and postoperative values. One study compared CWHTO and unicompartmental knee arthroplasty (UKA), and another study compared CWHTO and OWHTO. Five studies compared gait variables with those of healthy controls. One study compared operated limb gait variables with those in the non-operated limb. Gait speed, stride length, knee adduction moment, and lateral thrust were major variables assessed in 2 or more studies. Walking speed increased and stride length was increased or similar after HTO compared to the preoperative value in basic gait variables. Knee adduction moment and lateral thrust were decreased after HTO compared to the preoperative knee joint gait variables. Change in co-contraction of the medial side muscle after surgery differed depending on the degree of frontal plane alignment. The relationship between change in knee adduction moment and change in mechanical axis angle was controversial. Based on our systematic review and meta-analysis, walking speed and stride length increased after HTO. Knee adduction moment and lateral thrust decreased after HTO compared to the preoperative values of gait variables in the knee joint. Copyright © 2017 Elsevier B.V. All rights reserved.

Functional atlas of emotional faces processing: a voxel-based meta-analysis of 105 functional magnetic resonance imaging studies

PubMed Central

Fusar-Poli, Paolo; Placentino, Anna; Carletti, Francesco; Landi, Paola; Allen, Paul; Surguladze, Simon; Benedetti, Francesco; Abbamonte, Marta; Gasparotti, Roberto; Barale, Francesco; Perez, Jorge; McGuire, Philip; Politi, Pierluigi

2009-01-01

Background Most of our social interactions involve perception of emotional information from the faces of other people. Furthermore, such emotional processes are thought to be aberrant in a range of clinical disorders, including psychosis and depression. However, the exact neurofunctional maps underlying emotional facial processing are not well defined. Methods Two independent researchers conducted separate comprehensive PubMed (1990 to May 2008) searches to find all functional magnetic resonance imaging (fMRI) studies using a variant of the emotional faces paradigm in healthy participants. The search terms were: “fMRI AND happy faces,” “fMRI AND sad faces,” “fMRI AND fearful faces,” “fMRI AND angry faces,” “fMRI AND disgusted faces” and “fMRI AND neutral faces.” We extracted spatial coordinates and inserted them in an electronic database. We performed activation likelihood estimation analysis for voxel-based meta-analyses. Results Of the originally identified studies, 105 met our inclusion criteria. The overall database consisted of 1785 brain coordinates that yielded an overall sample of 1600 healthy participants. Quantitative voxel-based meta-analysis of brain activation provided neurofunctional maps for 1) main effect of human faces; 2) main effect of emotional valence; and 3) modulatory effect of age, sex, explicit versus implicit processing and magnetic field strength. Processing of emotional faces was associated with increased activation in a number of visual, limbic, temporoparietal and prefrontal areas; the putamen; and the cerebellum. Happy, fearful and sad faces specifically activated the amygdala, whereas angry or disgusted faces had no effect on this brain region. Furthermore, amygdala sensitivity was greater for fearful than for happy or sad faces. Insular activation was selectively reported during processing of disgusted and angry faces. However, insular sensitivity was greater for disgusted than for angry faces. Conversely

From Cortical and Subcortical Grey Matter Abnormalities to Neurobehavioral Phenotype of Angelman Syndrome: A Voxel-Based Morphometry Study

PubMed Central

Aghakhanyan, Gayane; Bonanni, Paolo; Randazzo, Giovanna; Nappi, Sara; Tessarotto, Federica; De Martin, Lara; Frijia, Francesca; De Marchi, Daniele; De Masi, Francesco; Kuppers, Beate; Lombardo, Francesco; Caramella, Davide; Montanaro, Domenico

2016-01-01

Angelman syndrome (AS) is a rare neurogenetic disorder due to loss of expression of maternal ubiquitin-protein ligase E3A (UBE3A) gene. It is characterized by severe developmental delay, speech impairment, movement or balance disorder and typical behavioral uniqueness. Affected individuals show normal magnetic resonance imaging (MRI) findings, although mild dysmyelination may be observed. In this study, we adopted a quantitative MRI analysis with voxel-based morphometry (FSL-VBM) method to investigate disease-related changes in the cortical/subcortical grey matter (GM) structures. Since 2006 to 2013 twenty-six AS patients were assessed by our multidisciplinary team. From those, sixteen AS children with confirmed maternal 15q11-q13 deletions (mean age 7.7 ± 3.6 years) and twenty-one age-matched controls were recruited. The developmental delay and motor dysfunction were assessed using Bayley III and Gross Motor Function Measure (GMFM). Principal component analysis (PCA) was applied to the clinical and neuropsychological datasets. High-resolution T1-weighted images were acquired and FSL-VBM approach was applied to investigate differences in the local GM volume and to correlate clinical and neuropsychological changes in the regional distribution of GM. We found bilateral GM volume loss in AS compared to control children in the striatum, limbic structures, insular and orbitofrontal cortices. Voxel-wise correlation analysis with the principal components of the PCA output revealed a strong relationship with GM volume in the superior parietal lobule and precuneus on the left hemisphere. The anatomical distribution of cortical/subcortical GM changes plausibly related to several clinical features of the disease and may provide an important morphological underpinning for clinical and neurobehavioral symptoms in children with AS. PMID:27626634

Intensive gait training with rhythmic auditory stimulation in individuals with chronic hemiparetic stroke: a pilot randomized controlled study.

PubMed

Cha, Yuri; Kim, Young; Hwang, Sujin; Chung, Yijung

2014-01-01

Motor relearning protocols should involve task-oriented movement, focused attention, and repetition of desired movements. To investigate the effect of intensive gait training with rhythmic auditory stimulation on postural control and gait performance in individuals with chronic hemiparetic stroke. Twenty patients with chronic hemiparetic stroke participated in this study. Subjects in the Rhythmic auditory stimulation training group (10 subjects) underwent intensive gait training with rhythmic auditory stimulation for a period of 6 weeks (30 min/day, five days/week), while those in the control group (10 subjects) underwent intensive gait training for the same duration. Two clinical measures, Berg balance scale and stroke specific quality of life scale, and a 2-demensional gait analysis system, were used as outcome measure. To provide rhythmic auditory stimulation during gait training, the MIDI Cuebase musical instrument digital interface program and a KM Player version 3.3 was utilized for this study. Intensive gait training with rhythmic auditory stimulation resulted in significant improvement in scores on the Berg balance scale, gait velocity, cadence, stride length and double support period in affected side, and stroke specific quality of life scale compared with the control group after training. Findings of this study suggest that intensive gait training with rhythmic auditory stimulation improves balance and gait performance as well as quality of life, in individuals with chronic hemiparetic stroke.

Influence of moderate training on gait and work capacity of fibromyalgia patients: a preliminary field study.

PubMed

Tiidus, Peter M; Pierrynowski, Michael; Dawson, Kimberley A

2002-12-01

This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0 ± 7.6 y) who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogue data acquisition system. Trunk flexibility was also assessed. No significant change in estimated work capacity or flexibility was seen between pre- post- and follow up times. Nevertheless, a significant increase in self selected walking speed (p < 0.05) and a trend toward a more normal gait pattern that was sustained in the follow up testing was noted. We had previously also reported a significant improvement in muscle pain and other fibromyalgia symptoms in this population consequent to the training program. It was concluded that mild exercise training that does not influence work capacity or trunk flexibility can nevertheless positively influence gait mechanics and fibromyalgia symptoms in female FS patients.

Influence of Moderate Training on Gait and Work Capacity of Fibromyalgia Patients: A Preliminary Field Study

PubMed Central

Tiidus, Peter M.; Pierrynowski, Michael; Dawson, Kimberley A.

2002-01-01

This field study examined the influence of moderate intensity training on gait patterns and work capacity of individuals with fibromyalgia syndrome (FS). FS is a chronic condition of unknown etiology, characterized by muscle tenderness, pain and stiffness and often accompanied by depression and fatigue which seems to occur primarily in middle aged females. There is no known cure for FS but treatment often includes a prescription of mild exercise. Few studies have evaluated the effectiveness of mild exercise on work capacity and gait patterns in FS patients. Participants were 14 females (age 47.0 ± 7.6 y) who participated in a 10 wk community based aerobic, strength and stretching program designed for FS individuals. Subjects were evaluated pre- and post-program and at a 2 month follow up. Work capacity was estimated by a sub-maximal PWC 170 cycle ergometer test and a Borg perceived exertion scale. Gait was assessed using OptoTrack three dimensional kinematics with 16 channel analogue data acquisition system. Trunk flexibility was also assessed. No significant change in estimated work capacity or flexibility was seen between pre- post- and follow up times. Nevertheless, a significant increase in self selected walking speed (p < 0.05) and a trend toward a more normal gait pattern that was sustained in the follow up testing was noted. We had previously also reported a significant improvement in muscle pain and other fibromyalgia symptoms in this population consequent to the training program. It was concluded that mild exercise training that does not influence work capacity or trunk flexibility can nevertheless positively influence gait mechanics and fibromyalgia symptoms in female FS patients. PMID:24748843

Clinical usefulness of the virtual reality-based postural control training on the gait ability in patients with stroke.

PubMed

Park, Yu-Hyung; Lee, Chi-Ho; Lee, Byoung-Hee

2013-01-01

This study is a single blind randomized controlled trial to determine the effect of virtual reality-based postural control training on the gait ability in patients with chronic stroke. Sixteen subjects were randomly assigned to either experimental group (VR, n= 8) or control group (CPT, n= 8). Subjects in both groups received conventional physical therapy for 60 min per day, five days per week during a period of four weeks. Subjects in the VR group received additional augmented reality-based training for 30 min per day, three days per week during a period of four weeks. The subjects were evaluated one week before and after participating in a four week training and follow-up at one month post-training. Data derived from the gait analyses included spatiotemporal gait parameters, 10 meters walking test (10 mWT). In the gait parameters, subjects in the VR group showed significant improvement, except for cadence at post-training and follow-up within the experimental group. However, no obvious significant improvement was observed within the control group. In between group comparisons, the experimental group (VR group) showed significantly greater improvement only in stride length compared with the control group (P< 0.05), however, no significant difference was observed in other gait parameters. In conclusion, we demonstrate significant improvement in gait ability in chronic stroke patients who received virtual reality based postural control training. These findings suggest that virtual reality (VR) postural control training using real-time information may be a useful approach for enhancement of gait ability in patients with chronic stroke.

A voxel based comparative analysis using magnetization transfer imaging and T1-weighted magnetic resonance imaging in progressive supranuclear palsy

PubMed Central

Sandhya, Mangalore; Saini, Jitender; Pasha, Shaik Afsar; Yadav, Ravi; Pal, Pramod Kumar

2014-01-01

Aims: In progressive supranuclear palsy (PSP) tissue damage occurs in specific cortical and subcortical regions. Voxel based analysis using T1-weighted images depict quantitative gray matter (GM) atrophy changes. Magnetization transfer (MT) imaging depicts qualitative changes in the brain parenchyma. The purpose of our study was to investigate whether MT imaging could indicate abnormalities in PSP. Settings and Design: A total of 10 patients with PSP (9 men and 1 woman) and 8 controls (5 men and 3 women) were studied with T1-weighted magnetic resonance imaging (MRI) and 3DMT imaging. Voxel based analysis of T1-weighted MRI was performed to investigate brain atrophy while MT was used to study qualitative abnormalities in the brain tissue. We used SPM8 to investigate group differences (with two sample t-test) using the GM and white matter (WM) segmented data. Results: T1-weighted imaging and MT are equally sensitive to detect changes in GM and WM in PSP. Magnetization transfer ratio images and magnetization-prepared rapid acquisition of gradient echo revealed extensive bilateral volume and qualitative changes in the orbitofrontal, prefrontal cortex and limbic lobe and sub cortical GM. The prefrontal structures involved were the rectal gyrus, medial, inferior frontal gyrus (IFG) and middle frontal gyrus (MFG). The anterior cingulate, cingulate gyrus and lingual gyrus of limbic lobe and subcortical structures such as caudate, thalamus, insula and claustrum were also involved. Cerebellar involvement mainly of anterior lobe was also noted. Conclusions: The findings suggest that voxel based MT imaging permits a whole brain unbiased investigation of central nervous system structural integrity in PSP. PMID:25024571

Gender-related differences in maximum gait speed and daily physical activity in elderly hospitalized cardiac inpatients: a preliminary study.

PubMed

Izawa, Kazuhiro P; Watanabe, Satoshi; Hirano, Yasuyuki; Matsushima, Shinya; Suzuki, Tomohiro; Oka, Koichiro; Kida, Keisuke; Suzuki, Kengo; Osada, Naohiko; Omiya, Kazuto; Brubaker, Peter H; Shimizu, Hiroyuki; Akashi, Yoshihiro J

2015-03-01

Maximum gait speed and physical activity (PA) relate to mortality and morbidity, but little is known about gender-related differences in these factors in elderly hospitalized cardiac inpatients. This study aimed to determine differences in maximum gait speed and daily measured PA based on sex and the relationship between these measures in elderly cardiac inpatients.A consecutive 268 elderly Japanese cardiac inpatients (mean age, 73.3 years) were enrolled and divided by sex into female (n = 75, 28%) and male (n = 193, 72%) groups. Patient characteristics and maximum gait speed, average step count, and PA energy expenditure (PAEE) in kilocalorie per day for 2 days assessed by accelerometer were compared between groups.Gait speed correlated positively with in-hospital PA measured by average daily step count (r = 0.46, P < 0.001) and average daily PAEE (r = 0.47, P < 0.001) in all patients. After adjustment for left ventricular ejection fraction, step counts and PAEE were significantly lower in females than males (2651.35 ± 1889.92 vs 4037.33 ± 1866.81 steps, P < 0.001; 52.74 ± 51.98 vs 99.33 ± 51.40 kcal, P < 0.001), respectively.Maximum gait speed was slower and PA lower in elderly female versus male inpatients. Minimum gait speed and step count values in this study might be minimum target values for elderly male and female Japanese cardiac inpatients.

Postural Control and Gait Performance in the Diabetic Peripheral Neuropathy: A Systematic Review.

PubMed

Mustapa, Amirah; Justine, Maria; Mohd Mustafah, Nadia; Jamil, Nursuriati; Manaf, Haidzir

2016-01-01

Purpose. The aim of this paper is to review the published studies on the characteristics of impairments in the postural control and gait performance in diabetic peripheral neuropathy (DPN). Methods. A review was performed by obtaining publication of all papers reporting on the postural control and gait performance in DPN from Google Scholar, Ovid, SAGE, Springerlink, Science Direct (SD), EBSCO Discovery Service, and Web of Science databases. The keywords used for searching were "postural control," "balance," "gait performance," "diabetes mellitus," and "diabetic peripheral neuropathy." Results. Total of 4,337 studies were hit in the search. 1,524 studies were screened on their titles and citations. Then, 79 studies were screened on their abstract. Only 38 studies were eligible to be selected: 17 studies on postural control and 21 studies on the gait performance. Most previous researches were found to have strong evidence of postural control impairments and noticeable gait deficits in DPN. Deterioration of somatosensory, visual, and vestibular systems with the pathologic condition of diabetes on cognitive impairment causes further instability of postural and gait performance in DPN. Conclusions. Postural instability and gait imbalance in DPN may contribute to high risk of fall incidence, especially in the geriatric population. Thus, further works are crucial to highlight this fact in the hospital based and community adults.

Anti-Dementia Drugs, Gait Performance and Mental Imagery of Gait: A Non-Randomized Open-Label Trial.

PubMed

Beauchet, Olivier; Barden, John; Liu-Ambrose, Teresa; Chester, Victoria L; Annweiler, Cedric; Szturm, Tony; Grenier, Sébastien; Léonard, Guillaume; Bherer, Louis; Allali, Gilles

2016-09-01

Few studies have examined the effect of anti-dementia drugs (i.e., acetylcholinesterase inhibitors and N-methyl-D-aspartate receptor antagonists) on gait performance. Past studies have focused on the stride time (i.e., gait cycle duration) but not on the mental imagery of gait. To compare mental imagery of gait and spatiotemporal gait parameters in patients with dementia [i.e., Alzheimer's disease (AD) and non-AD] before and after the use of anti-dementia drugs (i.e., acetylcholinesterase inhibitors and memantine) and in controls (i.e., patients with dementia who did not take anti-dementia drugs). A total of 112 patients (mean age 82.5 ± 4.2 years, 68.8 % female) with mild-to-moderate AD and non-AD dementia were included in this non-randomized open-label trial (n = 56 in the Intervention group, and n = 56 in the Control group matched for age, sex, and stage and type of dementia) nested in a cohort study (mean follow-up 238.5 ± 79.8 days). Mental imagery of gait was assessed with the actual and imagined Timed Up and Go tests (aTUG and iTUG) and the difference between aTUG and iTUG (i.e., delta-TUG). Spatiotemporal gait parameters were measured with the GAITRite(®) system during normal walking. Participants in the Intervention group had a longer iTUG time (p < 0.001) and a lower delta-TUG value (p = 0.001) at the follow-up compared with those in the Control group. There was a significant increase in iTUG (p = 0.001) and decrease in delta-TUG (p < 0.001) from baseline to the follow-up only in the Intervention group. Multiple linear regression showed that the use of anti-dementia drugs was associated with a longer iTUG time and a lower delta-TUG value (best performance, p < 0.002). Our findings showed an improvement in mental imagery of gait with the use of anti-dementia drugs, but no changes in actual gait performance. NCT01315704.

Accelerating IMRT optimization by voxel sampling

NASA Astrophysics Data System (ADS)

Martin, Benjamin C.; Bortfeld, Thomas R.; Castañon, David A.

2007-12-01

This paper presents a new method for accelerating intensity-modulated radiation therapy (IMRT) optimization using voxel sampling. Rather than calculating the dose to the entire patient at each step in the optimization, the dose is only calculated for some randomly selected voxels. Those voxels are then used to calculate estimates of the objective and gradient which are used in a randomized version of a steepest descent algorithm. By selecting different voxels on each step, we are able to find an optimal solution to the full problem. We also present an algorithm to automatically choose the best sampling rate for each structure within the patient during the optimization. Seeking further improvements, we experimented with several other gradient-based optimization algorithms and found that the delta-bar-delta algorithm performs well despite the randomness. Overall, we were able to achieve approximately an order of magnitude speedup on our test case as compared to steepest descent.

A Voxel-Based Morphometry Study of the Brain of University Students Majoring in Music and Nonmusic Disciplines.

PubMed

Sato, Kanako; Kirino, Eiji; Tanaka, Shoji

2015-01-01

The brain changes flexibly due to various experiences during the developmental stages of life. Previous voxel-based morphometry (VBM) studies have shown volumetric differences between musicians and nonmusicians in several brain regions including the superior temporal gyrus, sensorimotor areas, and superior parietal cortex. However, the reported brain regions depend on the study and are not necessarily consistent. By VBM, we investigated the effect of musical training on the brain structure by comparing university students majoring in music with those majoring in nonmusic disciplines. All participants were right-handed healthy Japanese females. We divided the nonmusic students into two groups and therefore examined three groups: music expert (ME), music hobby (MH), and nonmusic (NM) group. VBM showed that the ME group had the largest gray matter volumes in the right inferior frontal gyrus (IFG; BA 44), left middle occipital gyrus (BA 18), and bilateral lingual gyrus. These differences are considered to be caused by neuroplasticity during long and continuous musical training periods because the MH group showed intermediate volumes in these regions.

Morphological computation of multi-gaited robot locomotion based on free vibration.

PubMed

Reis, Murat; Yu, Xiaoxiang; Maheshwari, Nandan; Iida, Fumiya

2013-01-01

In recent years, there has been increasing interest in the study of gait patterns in both animals and robots, because it allows us to systematically investigate the underlying mechanisms of energetics, dexterity, and autonomy of adaptive systems. In particular, for morphological computation research, the control of dynamic legged robots and their gait transitions provides additional insights into the guiding principles from a synthetic viewpoint for the emergence of sensible self-organizing behaviors in more-degrees-of-freedom systems. This article presents a novel approach to the study of gait patterns, which makes use of the intrinsic mechanical dynamics of robotic systems. Each of the robots consists of a U-shaped elastic beam and exploits free vibration to generate different locomotion patterns. We developed a simplified physics model of these robots, and through experiments in simulation and real-world robotic platforms, we show three distinctive mechanisms for generating different gait patterns in these robots.

Multilayer Joint Gait-Pose Manifolds for Human Gait Motion Modeling.

PubMed

Ding, Meng; Fan, Guolian

2015-11-01

We present new multilayer joint gait-pose manifolds (multilayer JGPMs) for complex human gait motion modeling, where three latent variables are defined jointly in a low-dimensional manifold to represent a variety of body configurations. Specifically, the pose variable (along the pose manifold) denotes a specific stage in a walking cycle; the gait variable (along the gait manifold) represents different walking styles; and the linear scale variable characterizes the maximum stride in a walking cycle. We discuss two kinds of topological priors for coupling the pose and gait manifolds, i.e., cylindrical and toroidal, to examine their effectiveness and suitability for motion modeling. We resort to a topologically-constrained Gaussian process (GP) latent variable model to learn the multilayer JGPMs where two new techniques are introduced to facilitate model learning under limited training data. First is training data diversification that creates a set of simulated motion data with different strides. Second is the topology-aware local learning to speed up model learning by taking advantage of the local topological structure. The experimental results on the Carnegie Mellon University motion capture data demonstrate the advantages of our proposed multilayer models over several existing GP-based motion models in terms of the overall performance of human gait motion modeling.

Evaluation of a Gait Assessment Module Using 3D Motion Capture Technology

PubMed Central

Baskwill, Amanda J.; Belli, Patricia; Kelleher, Leila

2017-01-01

Background Gait analysis is the study of human locomotion. In massage therapy, this observation is part of an assessment process that informs treatment planning. Massage therapy students must apply the theory of gait assessment to simulated patients. At Humber College, the gait assessment module traditionally consists of a textbook reading and a three-hour, in-class session in which students perform gait assessment on each other. In 2015, Humber College acquired a three-dimensional motion capture system. Purpose The purpose was to evaluate the use of 3D motion capture in a gait assessment module compared to the traditional gait assessment module. Participants Semester 2 massage therapy students who were enrolled in Massage Theory 2 (n = 38). Research Design Quasi-experimental, wait-list comparison study. Intervention The intervention group participated in an in-class session with a Qualisys motion capture system. Main Outcome Measure(s) The outcomes included knowledge and application of gait assessment theory as measured by quizzes, and students’ satisfaction as measured through a questionnaire. Results There were no statistically significant differences in baseline and post-module knowledge between both groups (pre-module: p = .46; post-module: p = .63). There was also no difference between groups on the final application question (p = .13). The intervention group enjoyed the in-class session because they could visualize the content, whereas the comparison group enjoyed the interactivity of the session. The intervention group recommended adding the assessment of gait on their classmates to their experience. Both groups noted more time was needed for the gait assessment module. Conclusions Based on the results of this study, it is recommended that the gait assessment module combine both the traditional in-class session and the 3D motion capture system. PMID:28293329

An Ambulatory Method of Identifying Anterior Cruciate Ligament Reconstructed Gait Patterns

PubMed Central

Patterson, Matthew R.; Delahunt, Eamonn; Sweeney, Kevin T.; Caulfield, Brian

2014-01-01

The use of inertial sensors to characterize pathological gait has traditionally been based on the calculation of temporal and spatial gait variables from inertial sensor data. This approach has proved successful in the identification of gait deviations in populations where substantial differences from normal gait patterns exist; such as in Parkinsonian gait. However, it is not currently clear if this approach could identify more subtle gait deviations, such as those associated with musculoskeletal injury. This study investigates whether additional analysis of inertial sensor data, based on quantification of gyroscope features of interest, would provide further discriminant capability in this regard. The tested cohort consisted of a group of anterior cruciate ligament reconstructed (ACL-R) females and a group of non-injured female controls, each performed ten walking trials. Gait performance was measured simultaneously using inertial sensors and an optoelectronic marker based system. The ACL-R group displayed kinematic and kinetic deviations from the control group, but no temporal or spatial deviations. This study demonstrates that quantification of gyroscope features can successfully identify changes associated with ACL-R gait, which was not possible using spatial or temporal variables. This finding may also have a role in other clinical applications where small gait deviations exist. PMID:24451464

Greater cerebellar gray matter volume in car drivers: an exploratory voxel-based morphometry study

PubMed Central

Sakai, Hiroyuki; Ando, Takafumi; Sadato, Norihiro; Uchiyama, Yuji

2017-01-01

Previous functional neuroimaging studies have identified multiple brain areas associated with distinct aspects of car driving in simulated traffic environments. Few studies, however, have examined brain morphology associated with everyday car-driving experience in real traffic. Thus, the aim of the current study was to identify gray matter volume differences between drivers and non-drivers. We collected T1-weighted structural brain images from 73 healthy young adults (36 drivers and 37 non-drivers). We performed a whole-brain voxel-based morphometry analysis to examine between-group differences in regional gray matter volume. Compared with non-drivers, drivers showed significantly greater gray matter volume in the left cerebellar hemisphere, which has been associated with cognitive rather than motor functioning. In contrast, we found no brain areas with significantly greater gray matter volume in non-drivers compared with drivers. Our findings indicate that experience with everyday car driving in real traffic is associated with greater gray matter volume in the left cerebellar hemisphere. This brain area may be involved in abilities that are critical for driving a car, but are not commonly or frequently used during other daily activities. PMID:28417971

Greater cerebellar gray matter volume in car drivers: an exploratory voxel-based morphometry study.

PubMed

Sakai, Hiroyuki; Ando, Takafumi; Sadato, Norihiro; Uchiyama, Yuji

2017-04-18

Previous functional neuroimaging studies have identified multiple brain areas associated with distinct aspects of car driving in simulated traffic environments. Few studies, however, have examined brain morphology associated with everyday car-driving experience in real traffic. Thus, the aim of the current study was to identify gray matter volume differences between drivers and non-drivers. We collected T1-weighted structural brain images from 73 healthy young adults (36 drivers and 37 non-drivers). We performed a whole-brain voxel-based morphometry analysis to examine between-group differences in regional gray matter volume. Compared with non-drivers, drivers showed significantly greater gray matter volume in the left cerebellar hemisphere, which has been associated with cognitive rather than motor functioning. In contrast, we found no brain areas with significantly greater gray matter volume in non-drivers compared with drivers. Our findings indicate that experience with everyday car driving in real traffic is associated with greater gray matter volume in the left cerebellar hemisphere. This brain area may be involved in abilities that are critical for driving a car, but are not commonly or frequently used during other daily activities.

Gait performance and foot pressure distribution during wearable robot-assisted gait in elderly adults.

PubMed

Lee, Su-Hyun; Lee, Hwang-Jae; Chang, Won Hyuk; Choi, Byung-Ok; Lee, Jusuk; Kim, Jeonghun; Ryu, Gyu-Ha; Kim, Yun-Hee

2017-11-28

A robotic exoskeleton device is an intelligent system designed to improve gait performance and quality of life for the wearer. Robotic technology has developed rapidly in recent years, and several robot-assisted gait devices were developed to enhance gait function and activities of daily living in elderly adults and patients with gait disorders. In this study, we investigated the effects of the Gait-enhancing Mechatronic System (GEMS), a new wearable robotic hip-assist device developed by Samsung Electronics Co, Ltd., Korea, on gait performance and foot pressure distribution in elderly adults. Thirty elderly adults who had no neurological or musculoskeletal abnormalities affecting gait participated in this study. A three-dimensional (3D) motion capture system, surface electromyography and the F-Scan system were used to collect data on spatiotemporal gait parameters, muscle activity and foot pressure distribution under three conditions: free gait without robot assistance (FG), robot-assisted gait with zero torque (RAG-Z) and robot-assisted gait (RAG). We found increased gait speed, cadence, stride length and single support time in the RAG condition. Reduced rectus femoris and medial gastrocnemius muscle activity throughout the terminal stance phase and reduced effort of the medial gastrocnemius muscle throughout the pre-swing phase were also observed in the RAG condition. In addition, walking with the assistance of GEMS resulted in a significant increase in foot pressure distribution, specifically in maximum force and peak pressure of the total foot, medial masks, anterior masks and posterior masks. The results of the present study reveal that GEMS may present an alternative way of restoring age-related changes in gait such as gait instability with muscle weakness, reduced step force and lower foot pressure in elderly adults. In addition, GEMS improved gait performance by improving push-off power and walking speed and reducing muscle activity in the lower

A PDF-based classification of gait cadence patterns in patients with amyotrophic lateral sclerosis.

PubMed

Wu, Yunfeng; Ng, Sin Chun

2010-01-01

Amyotrophic lateral sclerosis (ALS) is a type of neurological disease due to the degeneration of motor neurons. During the course of such a progressive disease, it would be difficult for ALS patients to regulate normal locomotion, so that the gait stability becomes perturbed. This paper presents a pilot statistical study on the gait cadence (or stride interval) in ALS, based on the statistical analysis method. The probability density functions (PDFs) of stride interval were first estimated with the nonparametric Parzen-window method. We computed the mean of the left-foot stride interval and the modified Kullback-Leibler divergence (MKLD) from the PDFs estimated. The analysis results suggested that both of these two statistical parameters were significantly altered in ALS, and the least-squares support vector machine (LS-SVM) may effectively distinguish the stride patterns between the ALS patients and healthy controls, with an accurate rate of 82.8% and an area of 0.87 under the receiver operating characteristic curve.

Effects of circular gait training on balance, balance confidence in patients with stroke: a pilot study.

PubMed

Park, Shin-Kyu; Kim, Sung-Jin; Yoon, Tak Yong; Lee, Suk-Min

2018-05-01

[Purpose] This study aimed to investigate the effects of circular gait training on balance and balance confidence in patients with stroke. [Subjects and Methods] Fifteen patients with stroke were randomly divided into either the circular gait training (CGT) group (n=8) or the straight gait training (SGT) group (n=7). Both groups had conventional therapy that adhered to the neurodevelopmental treatment (NDT) approach, for 30 min. In addition, the CGT group performed circular gait training, and the SGT group practiced straight gait training for 30 min. Each intervention was applied for 1 h, 5 days a week, for 2 weeks. Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and Activities-specific Balance Confidence (ABC) scale were used to test balance and balance confidence. [Results] After the intervention, both groups showed significant increases in balance and balance confidence. Significant improvements in the balance of the CGT group compared with the SGT group were observed at post-assessment. [Conclusion] This study showed that circular gait training significantly improves balance in patients with stroke.

On Voxel based Iso-Tumor Control Probabilty and Iso-Complication Maps for Selective Boosting and Selective Avoidance Intensity Modulated Radiotherapy.

PubMed

Kim, Yusung; Tomé, Wolfgang A

2008-01-01

Voxel based iso-Tumor Control Probability (TCP) maps and iso-Complication maps are proposed as a plan-review tool especially for functional image-guided intensity-modulated radiotherapy (IMRT) strategies such as selective boosting (dose painting) and conformal avoidance IMRT. The maps employ voxel-based phenomenological biological dose-response models for target volumes and normal organs. Two IMRT strategies for prostate cancer, namely conventional uniform IMRT delivering an EUD = 84 Gy (equivalent uniform dose) to the entire PTV and selective boosting delivering an EUD = 82 Gy to the entire PTV, are investigated, to illustrate the advantages of this approach over iso-dose maps. Conventional uniform IMRT did yield a more uniform isodose map to the entire PTV while selective boosting did result in a nonuniform isodose map. However, when employing voxel based iso-TCP maps selective boosting exhibited a more uniform tumor control probability map compared to what could be achieved using conventional uniform IMRT, which showed TCP cold spots in high-risk tumor subvolumes despite delivering a higher EUD to the entire PTV. Voxel based iso-Complication maps are presented for rectum and bladder, and their utilization for selective avoidance IMRT strategies are discussed. We believe as the need for functional image guided treatment planning grows, voxel based iso-TCP and iso-Complication maps will become an important tool to assess the integrity of such treatment plans.

On Voxel based Iso-Tumor Control Probabilty and Iso-Complication Maps for Selective Boosting and Selective Avoidance Intensity Modulated Radiotherapy

PubMed Central

Kim, Yusung; Tomé, Wolfgang A.

2010-01-01

Summary Voxel based iso-Tumor Control Probability (TCP) maps and iso-Complication maps are proposed as a plan-review tool especially for functional image-guided intensity-modulated radiotherapy (IMRT) strategies such as selective boosting (dose painting) and conformal avoidance IMRT. The maps employ voxel-based phenomenological biological dose-response models for target volumes and normal organs. Two IMRT strategies for prostate cancer, namely conventional uniform IMRT delivering an EUD = 84 Gy (equivalent uniform dose) to the entire PTV and selective boosting delivering an EUD = 82 Gy to the entire PTV, are investigated, to illustrate the advantages of this approach over iso-dose maps. Conventional uniform IMRT did yield a more uniform isodose map to the entire PTV while selective boosting did result in a nonuniform isodose map. However, when employing voxel based iso-TCP maps selective boosting exhibited a more uniform tumor control probability map compared to what could be achieved using conventional uniform IMRT, which showed TCP cold spots in high-risk tumor subvolumes despite delivering a higher EUD to the entire PTV. Voxel based iso-Complication maps are presented for rectum and bladder, and their utilization for selective avoidance IMRT strategies are discussed. We believe as the need for functional image guided treatment planning grows, voxel based iso-TCP and iso-Complication maps will become an important tool to assess the integrity of such treatment plans. PMID:21151734

Physical Inactivity Predicts Slow Gait Speed in an Elderly Multi-Ethnic Cohort Study: The Northern Manhattan Study.

PubMed

Willey, Joshua Z; Moon, Yeseon P; Kulick, Erin R; Cheung, Ying Kuen; Wright, Clinton B; Sacco, Ralph L; Elkind, Mitchell S V

2017-01-01

Gait speed is associated with multiple adverse outcomes of aging. We hypothesized that physical inactivity would be prospectively inversely associated with gait speed independently of white matter hyperintensity volume and silent brain infarcts on MRI. Participants in the Northern Manhattan Study MRI sub-study had physical activity assessed when they were enrolled into the study. A mean of 5 years after the MRI, participants had gait speed measured via a timed 5-meter walk test. Physical inactivity was defined as reporting no leisure-time physical activity. Multi-variable logistic and quantile regression was performed to examine the associations between physical inactivity and future gait speed adjusted for confounders. Among 711 participants with MRI and gait speed measures (62% women, 71% Hispanic, mean age 74.1 ± 8.4), the mean gait speed was 1.02 ± 0.26 m/s. Physical inactivity was associated with a greater odds of gait speed in the lowest quartile (<0.85 m/s, adjusted OR 1.90, 95% CI 1.17-3.08), and in quantile regression with 0.06 m/s slower gait speed at the lowest 20 percentile (p = 0.005). Physical inactivity is associated with slower gait speed independently of osteoarthritis, grip strength, and subclinical ischemic brain injury. Modifying sedentary behavior poses a target for interventions aimed at reducing decline in mobility. © 2017 S. Karger AG, Basel.

Gait Speed among Older Participants Enrolled in an Evidence-Based Fall Risk Reduction Program: A Subgroup Analysis.

PubMed

Cho, Jinmyoung; Smith, Matthew Lee; Shubert, Tiffany E; Jiang, Luohua; Ahn, SangNam; Ory, Marcia G

2015-01-01

Functional decline is a primary risk factor for institutionalization and mortality among older adults. Although community-based fall risk reduction programs have been widely disseminated, little is known about their impact on gait speed, a key indicator of functional performance. Changes in functional performance between baseline and post-intervention were examined by means of timed up and go (TUG), a standardized functional assessment test administered to participants enrolled in A Matter of Balance/Volunteer Lay Leader (AMOB/VLL) model, an evidence-based fall risk reduction program. This study included 71 participants enrolled in an AMOB/VLL program in the Brazos Valley and South Plain regions of Texas. Paired t-tests were employed to assess program effects on gait speed at baseline and post-intervention for all participants and by subgroups of age, sex, living status, delivery sites, and self-rated health. The Bonferroni correction was applied to adjust inflated Type I error rate associated with performing multiple t-tests, for which p-values <0.0042 (i.e., 0.5/12 comparisons) were deemed statistically significant. Overall, gait speed of enrolled participants improved from baseline to post-intervention (t = 3.22, p = 0.002). Significant changes in TUG scores were observed among participants who lived with others (t = 4.45, p < 0.001), rated their health as excellent, very good, or good (t = 3.05, p = 0.003), and attended program workshops at senior centers (t = 3.52, p = 0.003). Findings suggest community-based fall risk reduction programs can improve gait speed for older adults. More translational research is needed to understand factors related to the effectiveness of fall risk reduction programs in various populations and settings.

Does robot-assisted gait training ameliorate gait abnormalities in multiple sclerosis? A pilot randomized-control trial.

PubMed

Straudi, S; Benedetti, M G; Venturini, E; Manca, M; Foti, C; Basaglia, N

2013-01-01

Gait disorders are common in multiple sclerosis (MS) and lead to a progressive reduction of function and quality of life. Test the effects of robot-assisted gait rehabilitation in MS subjects through a pilot randomized-controlled study. We enrolled MS subjects with Expanded Disability Status Scale scores within 4.5-6.5. The experimental group received 12 robot-assisted gait training sessions over 6 weeks. The control group received the same amount of conventional physiotherapy. Outcomes measures were both biomechanical assessment of gait, including kinematics and spatio-temporal parameters, and clinical test of walking endurance (six-minute walk test) and mobility (Up and Go Test). 16 subjects (n = 8 experimental group, n = 8 control group) were included in the final analysis. At baseline the two groups were similar in all variables, except for step length. Data showed walking endurance, as well as spatio-temporal gait parameters improvements after robot-assisted gait training. Pelvic antiversion and reduced hip extension during terminal stance ameliorated after aforementioned intervention. Robot-assisted gait training seems to be effective in increasing walking competency in MS subjects. Moreover, it could be helpful in restoring the kinematic of the hip and pelvis.

Asymmetry in gait pattern following tibial shaft fractures - a prospective one-year follow-up study of 49 patients.

PubMed

Larsen, Peter; Laessoe, Uffe; Rasmussen, Sten; Graven-Nielsen, Thomas; Berre Eriksen, Christian; Elsoe, Rasmus