A prospective cohort study investigating an exposure-response relationship among vibration-exposed male workers with numbness of the hands.

PubMed

Edlund, Maria; Burström, Lage; Gerhardsson, Lars; Lundström, Ronnie; Nilsson, Tohr; Sandén, Helena; Hagberg, Mats

2014-03-01

The aim of this study was to investigate the exposure-response relationship of hand-arm vibration exposure to neurological symptoms (numbness) of the hand in a cohort of vibration-exposed workers. The baseline cohort comprised 241 office and manual workers with and without exposure to hand-arm vibration. Numbness (the symptom or event) in the hand was assessed for all subjects at baseline and follow-ups after 5, 10, and 16 years. The workers were stratified into quartiles with no exposure in the first quartile and increasing intensity of exposure in quartiles 2-4 (groups 1-3). Data analysis was performed using survival analysis (time to event). Information on cumulative exposure and years of exposure to event was collected via questionnaires. Measurements were performed in accordance with the International Organization for Standardization (ISO) 5349-1. The hazard ratio (HR) of risk of event (numbness) differed statistically significantly between the non-exposed group (group 0) and the two higher exposure groups (groups 2 and 3). There was also a significant ratio difference between the lowest exposure group (group 1) and the two higher groups. The ratio for group 1 was 1.77 [95% confidence interval (95% CI) 0.96-3.26] compared with 3.78 (95% CI 2.15-6.62) and 5.31 (95% CI 3.06-9.20) for groups 2 and 3, respectively. The results suggest a dose-response relationship between vibration exposure and numbness of the hands. This underlines the importance of keeping vibration levels low to prevent neurological injury to the hands.

An examination of the vibration transmissibility of the hand-arm system in three orthogonal directions.

PubMed

Welcome, Daniel E; Dong, Ren G; Xu, Xueyan S; Warren, Christopher; McDowell, Thomas W; Wu, John Z

2015-02-01

The objective of this study is to enhance the understanding of the vibration transmission in the hand-arm system in three orthogonal directions ( X, Y , and Z ). For the first time, the transmitted vibrations distributed on the entire hand-arm system exposed in the three orthogonal directions via a 3-D vibration test system were measured using a 3-D laser vibrometer. Seven adult male subjects participated in the experiment. This study confirms that the vibration transmissibility generally decreased with the increase in distance from the hand and it varied with the vibration direction. Specifically, to the upper arm and shoulder, only moderate vibration transmission was measured in the test frequency range (16 to 500 Hz), and virtually no transmission was measured in the frequency range higher than 50 Hz. The resonance vibration on the forearm was primarily in the range of 16-30 Hz with the peak amplitude of approximately 1.5 times of the input vibration amplitude. The major resonance on the dorsal surfaces of the hand and wrist occurred at around 30-40 Hz and, in the Y direction, with peak amplitude of more than 2.5 times of the input amplitude. At higher than 50 Hz, vibration transmission was effectively limited to the hand and fingers. A major finger resonance was observed at around 100 Hz in the X and Y directions and around 200 Hz in the Z direction. In the fingers, the resonance magnitude in the Z direction was generally the lowest, and the resonance magnitude in the Y direction was generally the highest with the resonance amplitude of 3 times the input vibration, which was similar to the transmissibility at the wrist and hand dorsum. The implications of the results are discussed. Prolonged, intensive exposure to hand-transmitted vibration could result in hand-arm vibration syndrome. While the syndrome's precise mechanisms remain unclear, the characterization of the vibration transmissibility of the system in the three orthogonal dimensions performed in this study can help understand the syndrome and help develop improved frequency weightings for assessing the risk of the exposure for developing various components of the syndrome.

An examination of the vibration transmissibility of the hand-arm system in three orthogonal directions

PubMed Central

Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.; Wu, John Z.

2015-01-01

The objective of this study is to enhance the understanding of the vibration transmission in the hand-arm system in three orthogonal directions (X, Y, and Z). For the first time, the transmitted vibrations distributed on the entire hand-arm system exposed in the three orthogonal directions via a 3-D vibration test system were measured using a 3-D laser vibrometer. Seven adult male subjects participated in the experiment. This study confirms that the vibration transmissibility generally decreased with the increase in distance from the hand and it varied with the vibration direction. Specifically, to the upper arm and shoulder, only moderate vibration transmission was measured in the test frequency range (16 to 500 Hz), and virtually no transmission was measured in the frequency range higher than 50 Hz. The resonance vibration on the forearm was primarily in the range of 16–30 Hz with the peak amplitude of approximately 1.5 times of the input vibration amplitude. The major resonance on the dorsal surfaces of the hand and wrist occurred at around 30–40 Hz and, in the Y direction, with peak amplitude of more than 2.5 times of the input amplitude. At higher than 50 Hz, vibration transmission was effectively limited to the hand and fingers. A major finger resonance was observed at around 100 Hz in the X and Y directions and around 200 Hz in the Z direction. In the fingers, the resonance magnitude in the Z direction was generally the lowest, and the resonance magnitude in the Y direction was generally the highest with the resonance amplitude of 3 times the input vibration, which was similar to the transmissibility at the wrist and hand dorsum. The implications of the results are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration could result in hand-arm vibration syndrome. While the syndrome's precise mechanisms remain unclear, the characterization of the vibration transmissibility of the system in the three orthogonal dimensions performed in this study can help understand the syndrome and help develop improved frequency weightings for assessing the risk of the exposure for developing various components of the syndrome. PMID:26635424

Exposure assessment in health assessments for hand-arm vibration syndrome.

PubMed

Mason, H J; Poole, K; Young, C

2011-08-01

Assessing past cumulative vibration exposure is part of assessing the risk of hand-arm vibration syndrome (HAVS) in workers exposed to hand-arm vibration and invariably forms part of a medical assessment of such workers. To investigate the strength of relationships between the presence and severity of HAVS and different cumulative exposure metrics obtained from a self-reporting questionnaire. Cumulative exposure metrics were constructed from a tool-based questionnaire applied in a group of HAVS referrals and workplace field studies. These metrics included simple years of vibration exposure, cumulative total hours of all tool use and differing combinations of acceleration magnitudes for specific tools and their daily use, including the current frequency-weighting method contained in ISO 5349-1:2001. Use of simple years of exposure is a weak predictor of HAVS or its increasing severity. The calculation of cumulative hours across all vibrating tools used is a more powerful predictor. More complex calculations based on involving likely acceleration data for specific classes of tools, either frequency weighted or not, did not offer a clear further advantage in this dataset. This may be due to the uncertainty associated with workers' recall of their past tool usage or the variability between tools in the magnitude of their vibration emission. Assessing years of exposure or 'latency' in a worker should be replaced by cumulative hours of tool use. This can be readily obtained using a tool-pictogram-based self-reporting questionnaire and a simple spreadsheet calculation.

Vibrations transmitted from human hands to upper arm, shoulder, back, neck, and head.

PubMed

Xu, Xueyan S; Dong, Ren G; Welcome, Daniel E; Warren, Christopher; McDowell, Thomas W; Wu, John Z

2017-12-01

Some powered hand tools can generate significant vibration at frequencies below 25 Hz. It is not clear whether such vibration can be effectively transmitted to the upper arm, shoulder, neck, and head and cause adverse effects in these substructures. The objective of this study is to investigate the vibration transmission from the human hands to these substructures. Eight human subjects participated in the experiment, which was conducted on a 1-D vibration test system. Unlike many vibration transmission studies, both the right and left hand-arm systems were simultaneously exposed to the vibration to simulate a working posture in the experiment. A laser vibrometer and three accelerometers were used to measure the vibration transmitted to the substructures. The apparent mass at the palm of each hand was also measured to help in understanding the transmitted vibration and biodynamic response. This study found that the upper arm resonance frequency was 7-12 Hz, the shoulder resonance was 7-9 Hz, and the back and neck resonances were 6-7 Hz. The responses were affected by the hand-arm posture, applied hand force, and vibration magnitude. The transmissibility measured on the upper arm had a trend similar to that of the apparent mass measured at the palm in their major resonant frequency ranges. The implications of the results are discussed. Musculoskeletal disorders (MSDs) of the shoulder and neck are important issues among many workers. Many of these workers use heavy-duty powered hand tools. The combined mechanical loads and vibration exposures are among the major factors contributing to the development of MSDs. The vibration characteristics of the body segments examined in this study can be used to help understand MSDs and to help develop more effective intervention methods.

Vibrations transmitted from human hands to upper arm, shoulder, back, neck, and head

PubMed Central

Xu, Xueyan S.; Dong, Ren G.; Welcome, Daniel E.; Warren, Christopher; McDowell, Thomas W.; Wu, John Z.

2016-01-01

Some powered hand tools can generate significant vibration at frequencies below 25 Hz. It is not clear whether such vibration can be effectively transmitted to the upper arm, shoulder, neck, and head and cause adverse effects in these substructures. The objective of this study is to investigate the vibration transmission from the human hands to these substructures. Eight human subjects participated in the experiment, which was conducted on a 1-D vibration test system. Unlike many vibration transmission studies, both the right and left hand-arm systems were simultaneously exposed to the vibration to simulate a working posture in the experiment. A laser vibrometer and three accelerometers were used to measure the vibration transmitted to the substructures. The apparent mass at the palm of each hand was also measured to help in understanding the transmitted vibration and biodynamic response. This study found that the upper arm resonance frequency was 7–12 Hz, the shoulder resonance was 7–9 Hz, and the back and neck resonances were 6–7 Hz. The responses were affected by the hand-arm posture, applied hand force, and vibration magnitude. The transmissibility measured on the upper arm had a trend similar to that of the apparent mass measured at the palm in their major resonant frequency ranges. The implications of the results are discussed. Relevance to industry Musculoskeletal disorders (MSDs) of the shoulder and neck are important issues among many workers. Many of these workers use heavy-duty powered hand tools. The combined mechanical loads and vibration exposures are among the major factors contributing to the development of MSDs. The vibration characteristics of the body segments examined in this study can be used to help understand MSDs and to help develop more effective intervention methods. PMID:29123326

Recent advances in biodynamics of human hand-arm system.

PubMed

Dong, Ren G; Wu, John Z; Welcome, Daniel E

2005-07-01

The biodynamics of human hand-arm system is one of the most important foundations for the measurement, evaluation, and risk assessment of hand-transmitted vibration (HTV) exposure. This paper presents a new conceptual model relating factors influencing cause-effect relationships for HTV exposure, a new study strategy, and a comprehensive review of the recent advances in the biodynamics closely associated with HTV exposure. The review covers the following five aspects: theoretical modeling of biodynamic responses, vibration transmissibility, driving-point biodynamic responses, evaluation of anti-vibration gloves, and applied forces. This review finds that some significant advances in each of these aspects have been achieved in the recent years. Several important issues and problems in the biodynamic measurement have been identified and resolved, which has significantly helped improve the reliability and accuracy of the experimental data. The results reported in recent years suggest that, from the point of view of biodynamics, the frequency weighting specified in ISO 5349-1 (2001) overestimates the low frequency effect but underestimates the high frequency effect on the fingers and hand. The major problems, issues, and topics for further studies are also outlined in this paper. It is anticipated that the further studies of the biodynamics of the system will eventually lead to establishment of a robust vibration exposure theory. Although this review focuses on the biodynamics of the hand-arm system, the fundamental concepts and some methodologies reviewed in this paper may also be applicable for the study of whole-body vibration exposure.

Vibration syndrome in railway track maintenance workers.

PubMed

Virokannas, H; Anttonen, H; Niskanen, J

1995-01-01

An inquiry was sent to all railway maintenance workers in three railway districts in Finland and hand-arm vibration was measured on the handlebars of tools used by maintenance workers. The study group included 252 (82%) subjects, whose mean age was 41 years and who had worked in track maintenance for 14 years (SD 9). In Finland there are over 600 railway maintenance workers who use vibrating tools. The frequency-weighted acceleration of hand-arm vibration was calculated according to the ISO 5349 standard. Hand-held tamping machines had caused most of the vibration exposure, and aw4h was 10.6 m/s2 measured on the handlebar of tamping machine, but many workers also used other vibrating tools. The annual vibration level was 2.5 m/s2 when the use of all vibrating tools and the exposure time was taken into account. In the questionnaire the prevalence of vibration-induced white finger (VWF) was 14% in the entire material, and the prevalence of VWF increased significantly with the total duration of the maintenance work. In addition, 39% of the subjects had suffered numbness of the hands, and the prevalence of hand numbness also increased significantly with the total duration of maintenance work. According to the measurements of vibration and the prevalence of hand symptoms the present investigation indicates vibration syndrome as being related to railway track maintenance work. In the exposure group, where tamping machines mainly were used and exposure to other vibration was small, the prevalence of VWF was also significantly higher, but the prevalence of hand numbness insignificant compared with the control group. In this study vascular and nerve hand symptoms were considered to cause serious trouble in work by 4-11% of the maintenance workers.

The study on hand-arm vibration syndrome in China.

PubMed

Lin, Wang; Chunzhi, Zhang; Qiang, Zhang; Kai, Zhang; Xiaoli, Zeng

2005-07-01

To review the main achievement and problems of study on hand-arm vibration syndrome in China. The epidemiological and clinical study indicate that HAVS was reported from almost provinces in China, the prevalence of VWF ranges from 2.5% to 82.8% in the workers with vibrating tool use. The exposure-response relationship between prevalence of VWF and intensity and duration of exposed to hand-transmitted vibration has confirmed. Diagnostic criteria of HAVS has been established and performed by Chinese government in 1985, and it was revised by government as a national standard for occupational health in 2002. The "hygienic standard for hand-transmitted vibration in workplace" as a national standard and the "methods of measurement and assessment for hand-transmitted vibration" as a recommend standard were published by government also. The limited value of exposed to hand-arm vibration was 5.0 m/s2 that is energy equivalent frequency-weighted acceleration for a period of 4 h (ahw(4)). There are some problems in this field of China need to further study in the future.

Role of Kv4.3 in Vibration-Induced Muscle Pain in the Rat.

PubMed

Conner, Lindsay B; Alvarez, Pedro; Bogen, Oliver; Levine, Jon D

2016-04-01

We hypothesized that changes in the expression of voltage-gated potassium channel (Kv) 4.3 contribute to the mechanical hyperalgesia induced by vibration injury, in a rodent model for hand-arm vibration syndrome in humans. Here we show that the exposure of the gastrocnemius muscle to vibration injury induces muscle hyperalgesia that is accompanied by a significant downregulation of Kv4.3 in affected sensory nerve fibers in dorsal root ganglia. We additionally show that the intrathecal administration of antisense oligonucleotides for Kv4.3 messenger RNA itself induces muscle hyperalgesia in the rat. Our results suggest that attenuation in the expression of Kv4.3 may contribute to neuropathic pain in people affected by hand-arm vibration syndrome. Our findings establish Kv4.3 as a potential molecular target for the treatment of hand-arm vibration syndrome. Copyright © 2016 American Pain Society. Published by Elsevier Inc. All rights reserved.

Dose-response relationship between hand-transmitted vibration and hand-arm vibration syndrome in a tropical environment.

PubMed

Su, Anselm Ting; Maeda, Setsuo; Fukumoto, Jin; Darus, Azlan; Hoe, Victor C W; Miyai, Nobuyuki; Isahak, Marzuki; Takemura, Shigeki; Bulgiba, Awang; Yoshimasu, Kouichi; Miyashita, Kazuhisa

2013-07-01

The dose-response relationship for hand-transmitted vibration has been investigated extensively in temperate environments. Since the clinical features of hand-arm vibration syndrome (HAVS) differ between the temperate and tropical environment, we conducted this study to investigate the dose-response relationship of HAVS in a tropical environment. A total of 173 male construction, forestry and automobile manufacturing plant workers in Malaysia were recruited into this study between August 2011 and 2012. The participants were interviewed for history of vibration exposure and HAVS symptoms, followed by hand functions evaluation and vibration measurement. Three types of vibration doses-lifetime vibration dose (LVD), total operating time (TOT) and cumulative exposure index (CEI)-were calculated and its log values were regressed against the symptoms of HAVS. The correlation between each vibration exposure dose and the hand function evaluation results was obtained. The adjusted prevalence ratio for finger tingling and numbness was 3.34 (95% CI 1.27 to 8.98) for subjects with lnLVD≥20 ln m(2) s(-4) against those <16 ln m(2) s(-4). Similar dose-response pattern was found for CEI but not for TOT. No subject reported white finger. The prevalence of finger coldness did not increase with any of the vibration doses. Vibrotactile perception thresholds correlated moderately with lnLVD and lnCEI. The dose-response relationship of HAVS in a tropical environment is valid for finger tingling and numbness. The LVD and CEI are more useful than TOT when evaluating the dose-response pattern of a heterogeneous group of vibratory tools workers.

The effects of vibration-reducing gloves on finger vibration

PubMed Central

Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.

2015-01-01

Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration can cause hand-arm vibration syndrome. Vibration-reducing gloves have been used as an alternative approach to reduce the vibration exposure. However, their effectiveness for reducing finger-transmitted vibrations remains unclear. This study enhanced the understanding of the glove effects on finger vibration and provided useful information on the effectiveness of typical VR gloves at reducing the vibration transmitted to the fingers. The new results and knowledge can be used to help select appropriate gloves for the operations of powered hand tools, to help perform risk assessment of the vibration exposure, and to help design better VR gloves. PMID:26543297

Work ability in vibration-exposed workers.

PubMed

Gerhardsson, L; Hagberg, M

2014-12-01

Hand-arm vibration exposure may cause hand-arm vibration syndrome (HAVS) including sensorineural disturbances. To investigate which factors had the strongest impact on work ability in vibration-exposed workers. A cross-sectional study in which vibration-exposed workers referred to a department of occupational and environmental medicine were compared with a randomized sample of unexposed subjects from the general population of the city of Gothenburg. All participants underwent a structured interview, answered several questionnaires and had a physical examination including measurements of hand and finger muscle strength and vibrotactile and thermal perception thresholds. The vibration-exposed group (47 subjects) showed significantly reduced sensitivity to cold and warmth in digit 2 bilaterally (P < 0.01) and in digit 5 in the left hand (P < 0.05) and to warmth in digit 5 in the right hand (P < 0.01), compared with the 18 referents. Similarly, tactilometry showed significantly raised vibration perception thresholds among the workers (P < 0.05). A strong relationship was found for the following multiple regression model: estimated work ability = 11.4 - 0.1 × age - 2.3 × current stress level - 2.5 × current pain in hands/arms (multiple r = 0.68; P < 0.001). Vibration-exposed workers showed raised vibrotactile and thermal perception thresholds, compared with unexposed referents. Multiple regression analysis indicated that stress disorders and muscle pain in hands/arms must also be considered when evaluating work ability among subjects with HAVS. © The Author 2014. Published by Oxford University Press on behalf of the Society of Occupational Medicine.

Tremor and hand-arm vibration syndrome (HAVS) in road maintenance workers.

PubMed

Bast-Pettersen, Rita; Ulvestad, Bente; Færden, Karl; Clemm, Thomas Aleksander C; Olsen, Raymond; Ellingsen, Dag Gunnar; Nordby, Karl-Christian

2017-01-01

The aim of this study was to evaluate postural and rest tremor among workers using vibrating hand tools, taking into account the possible effects of toxicants such as alcohol and tobacco. A further aim was to study workers diagnosed with hand-arm vibration syndrome (HAVS) at the time of examination. This study comprises 103 road maintenance workers, 55 exposed to vibrating hand tools (age 41.0 years; range 21-62) and 48 referents (age 38.5 years; range 19-64). They were examined with the CATSYS Tremor Pen ® . Exposure to vibrating tools and serum biomarkers of alcohol and tobacco consumption were measured. Cumulative exposure to vibrating tools was associated with increased postural (p < 0.01) and rest tremor (p < 0.05) and with a higher Center Frequency of postural tremor (p < 0.01) among smokers and users of smokeless tobacco. Rest tremor Center Frequency was higher than postural tremor frequency (p < 0.001). The main findings indicate an association between cumulative exposure to hand-held vibrating tools, tremor parameters and consumption of tobacco products. The hand position is important when testing for tremor. Rest tremor had a higher Center Frequency. Postural tremor was more strongly associated with exposure than rest tremor. The finding of increased tremor among the HAVS subjects indicated that tremor might be a part of the clinical picture of a HAVS diagnosis. As with all cross-sectional studies, inferences should be made with caution when drawing conclusions about associations between exposure and possible effects. Future research using longitudinal design is required to validate the findings of the present study.

Hand-arm vibration syndrome from exposure to high-pressure hoses.

PubMed

Cooke, R; House, R; Lawson, I J; Pelmear, P L; Wills, M

2001-09-01

Hand-arm vibration syndrome has been reported in the literature to occur following exposure to vibration from the use of many tools, but to date there have been no case reports of its occurrence in workers who have used high-pressure hoses, alone or with other tools. To remedy this, the case histories of nine subjects (two without mixed exposure) examined in the UK and Canada are presented, together with their severity classified according to the Stockholm scales. Attention is drawn to the need to use multiple diagnostic tests to establish the diagnosis and the need to implement vibration isolation and damping methodologies, as and when feasible, with respect to hose nozzles in order to minimize the hazard. The ultimate goal for tool manufacturers, hygienists and engineers should be to reduce workplace vibration levels to meet national and international guidelines and legislation, including UK Health & Safety Executive guidelines and European Economic Community directives. The respective risk levels are presented, together with vibration measurements on hoses used by some of the cases.

The relationships between hand coupling force and vibration biodynamic responses of the hand-arm system.

PubMed

Pan, Daniel; Xu, Xueyan S; Welcome, Daniel E; McDowell, Thomas W; Warren, Christopher; Wu, John; Dong, Ren G

2018-06-01

This study conducted two series of experiments to investigate the relationships between hand coupling force and biodynamic responses of the hand-arm system. In the first experiment, the vibration transmissibility on the system was measured as a continuous function of grip force while the hand was subjected to discrete sinusoidal excitations. In the second experiment, the biodynamic responses of the system subjected to a broadband random vibration were measured under five levels of grip forces and a combination of grip and push forces. This study found that the transmissibility at each given frequency increased with the increase in the grip force before reaching a maximum level. The transmissibility then tended to plateau or decrease when the grip force was further increased. This threshold force increased with an increase in the vibration frequency. These relationships remained the same for both types of vibrations. The implications of the experimental results are discussed. Practitioner Summary: Shocks and vibrations transmitted to the hand-arm system may cause injuries and disorders of the system. How to take hand coupling force into account in the risk assessment of vibration exposure remains an important issue for further studies. This study is designed and conducted to help resolve this issue.

[Occupational exposure to hand-transmitted vibration in Poland].

PubMed

Harazin, Barbara; Zieliński, Grzegorz

2004-01-01

Occupational exposure to hand transmitted vibration may cause disorders in upper extremities known as hand-arm vibration syndrome. Therefore it is essential to know the sources of vibration, occupational groups exposed to vibration and the number of exposed workers. The aim of the study was to estimate the number of men and women exposed to hand-transmitted vibration in Poland. The completed questionnaires were obtained from 265 (80%) sanitary inspection stations. They included questions on: the name of workplaces, the name and the type of vibration sources, workers' gender, the number of workers exposed to vibration, indicating the extent of exposure measured against the three threshold limit values (< 0.5 TLV; 0.5 < TLV < 1 and > 1 TLV), and the number of workers exposed to hand-transmitted vibration not documented by measurements in a particular workplaces, indicating one of the three possible kinds of exposure (occasional, periodical and constant). The questionnaire data were based on measurements and analyses performed in 1997-2000. The results of the study showed that vibrating tools used by grinders, fitters, locksmiths, rammers, road workers, carpenters and smiths proved to be the most frequent sources of hand-transmitted vibration. It was revealed that 78.6% of operators of these tools were exposed to vibration exceeding 1 TLV. The study also indicated that 17,000 workers, including 1700 women, were exposed to vibration exceeding the threshold limit values.

Short daily exposure to hand-arm vibrations in Swedish car mechanics.

PubMed

Barregård, Lars

2003-01-01

The aim of the study was to examine the daily exposure times to hand-arm vibrations in Swedish car mechanics, to test a method for estimating the exposure time without observing the workers for whole days, and to use the results for predicting the prevalence of vibration-induced white fingers (VWF) by the ISO 5349-model. Six garages were surveyed. In each garage, 5-10 car mechanics were observed in random order every 30 seconds throughout working days. The daily exposure time for each mechanic was estimated from the fraction of the observations that the mechanic was exposed. A total of 51 mechanics were observed, most of them on two different working days, yielding estimates for 95 days. The median effective exposure time was 10 minutes per day (95% confidence interval 5-15 minutes, arithmetic mean 14 minutes, maximum 80 minutes), and most of the exposure time was attributable to fastening and loosening nuts. The within-worker and between-worker variability was high (total sigma2 0.99, geometric standard deviation of 2.7). Using the observed exposure time and data on vibration levels of the main tools in Swedish car mechanics (average weighted acceleration level of 3.5 m/s2), the model in ISO-standard 5349 would predict that only three percent of the car mechanics will suffer from VWF after 20 years of exposure. In contrast, a recent survey of VWF showed the prevalence to be 25 percent. The precision of the observation method was estimated and was found to be good for the group daily mean. On the individual level the precision was only acceptable if the daily exposure time was > or = 40 minutes. In conclusion, the daily exposure time was short and the vibration level was limited. Nevertheless, hand-arm vibrations cause VWF in a significant number of car mechanics. The method of observing workers intermittently seemed to work well.

Interethnic differences at the thermometric response to cold test: functional disorders of blood circulation in hand fingers and exposure to hand-arm vibration.

PubMed

Riolfi, A; Princivalle, A; Romeo, L; Caramaschi, P; Perbellini, L

2008-02-01

To report some notable aspects regarding thermometric response to cold test in black African subjects compared with Caucasians: both groups comprised persons exposed to hand-arm vibration and controls. An overall sample of 48 workers was examined in order to study their blood circulation in hand fingers: a control group of 12 healthy Caucasian workers never exposed before to hand-arm vibration; 12 Caucasian workers exposed for several years to vibrating tools and affected by occupational Raynaud's phenomenon; 12 healthy black African workers exposed to hand-arm vibration for almost 3 years; and 12 healthy black African workers never exposed to hand-arm vibration. Computerized skin thermometry was performed and thermometric curves were analyzed according to thermometric interpretation criteria such as the area-over-curve (AOC), the fifth minute of recovery/baseline temperature ratio (5REC/BT) and the temperature at the tenth minute of recovery (10REC) after cold test. Thermometric parameters in Caucasian subjects confirmed the basis of the existing literature in controls (basal finger temperature higher than 32 degrees C and complete recovery to the initial temperature after the cold test) and also in patients with Raynaud's phenomenon (basal temperature often lower than control subjects and slow recovery of finger temperature after cold test). Statistically significant difference was found between healthy Caucasians and healthy black subjects in all the parameters tested: healthy black subjects showed values of AOC and 10REC suggesting almost constantly lower finger temperatures during the thermometry test. Black people, both exposed and non-exposed to hand-arm vibration showed thermometric parameters suggesting poor blood microcirculation, which seems even poorer than in Caucasian people complaining Raynaud's phenomenon. Our chronothermometric tests suggest some significant interethnic differences in peripheral microcirculation, which seems rather poor in black African subjects in comparison with Caucasians.

Hand-arm vibration syndrome: What family physicians should know.

PubMed

Shen, Shixin Cindy; House, Ronald A

2017-03-01

To provide family physicians with an understanding of the epidemiology, pathogenesis, symptoms, diagnosis, and management of hand-arm vibration syndrome (HAVS), an important and common occupational disease in Canada. A MEDLINE search was conducted for research and review articles on HAVS. A Google search was conducted to obtain gray literature relevant to the Canadian context. Additional references were obtained from the articles identified. Hand-arm vibration syndrome is a prevalent occupational disease affecting workers in multiple industries in which vibrating tools are used. However, it is underdiagnosed in Canada. It has 3 components-vascular, in the form of secondary Raynaud phenomenon; sensorineural; and musculoskeletal. Hand-arm vibration syndrome in its more advanced stages contributes to substantial disability and poor quality of life. Its diagnosis requires careful history taking, in particular occupational history, physical examination, laboratory tests to rule out alternative diagnoses, and referral to an occupational medicine specialist for additional investigations. Management involves reduction of vibration exposure, avoidance of cold conditions, smoking cessation, and medication. To ensure timely diagnosis of HAVS and improve prognosis and quality of life, family physicians should be aware of this common occupational disease and be able to elicit the relevant occupational history, refer patients to occupational medicine clinics, and appropriately initiate compensation claims. Copyright© the College of Family Physicians of Canada.

Quantitatively measured tremor in hand-arm vibration-exposed workers.

PubMed

Edlund, Maria; Burström, Lage; Hagberg, Mats; Lundström, Ronnie; Nilsson, Tohr; Sandén, Helena; Wastensson, Gunilla

2015-04-01

The aim of the present study was to investigate the possible increase in hand tremor in relation to hand-arm vibration (HAV) exposure in a cohort of exposed and unexposed workers. Participants were 178 male workers with or without exposure to HAV. The study is cross-sectional regarding the outcome of tremor and has a longitudinal design with respect to exposure. The dose of HAV exposure was collected via questionnaires and measurements at several follow-ups. The CATSYS Tremor Pen(®) was used for measuring postural tremor. Multiple linear regression methods were used to analyze associations between different tremor variables and HAV exposure, along with predictor variables with biological relevance. There were no statistically significant associations between the different tremor variables and cumulative HAV or current exposure. Age was a statistically significant predictor of variation in tremor outcomes for three of the four tremor variables, whereas nicotine use was a statistically significant predictor of either left or right hand or both hands for all four tremor variables. In the present study, there was no evidence of an exposure-response association between HAV exposure and measured postural tremor. Increase in age and nicotine use appeared to be the strongest predictors of tremor.

Anti-vibration gloves?

PubMed

Hewitt, Sue; Dong, Ren G; Welcome, Daniel E; McDowell, Thomas W

2015-03-01

For exposure to hand-transmitted vibration (HTV), personal protective equipment is sold in the form of anti-vibration (AV) gloves, but it remains unclear how much these gloves actually reduce vibration exposure or prevent the development of hand-arm vibration syndrome in the workplace. This commentary describes some of the issues that surround the classification of AV gloves, the assessment of their effectiveness and their applicability in the workplace. The available information shows that AV gloves are unreliable as devices for controlling HTV exposures. Other means of vibration control, such as using alternative production techniques, low-vibration machinery, routine preventative maintenance regimes, and controlling exposure durations are far more likely to deliver effective vibration reductions and should be implemented. Furthermore, AV gloves may introduce some adverse effects such as increasing grip force and reducing manual dexterity. Therefore, one should balance the benefits of AV gloves and their potential adverse effects if their use is considered. © Crown copyright 2014.

Frequency weightings based on biodynamics of fingers-hand-arm system.

PubMed

Dong, Ren G; Welcome, Daniel E; Wu, John Z

2005-07-01

The frequency weighting for assessing hand-transmitted vibration exposure is critical to obtaining a true dose-response relationship. Any valid weighting must have a solid theoretical foundation. The objectives of this study are to examine the biodynamic foundation for assessing the vibration exposure and to develop a set of biodynamic methods to formulate the frequency weightings for different anatomical locations of the fingers-hand-arm system. The vibration transmissibility measured on the fingers, hand, wrist, elbow, shoulder, and head was used to define the transmitted acceleration-based (TAB) frequency weighting. The apparent masses measured at the fingers and the palm of the hand were used to construct the biodynamic force-based (BFB) weightings. These weightings were compared with the ISO weighting specified in ISO 5349-1 (2001). The results of this study suggest that the frequency weightings for the vibration-induced problems at different anatomical locations of the hand-arm system can be basically divided into three groups: (a) the weighting for the fingers and hand, (b) the weighting for the wrist, elbow, and shoulder, and (c) the weighting for the head. The ISO weighting is highly correlated with the weighting for the second group but not with the first and third groups. The TAB and BFB finger weightings are quite different at frequencies lower than 100 Hz, but they show similar trends at higher frequencies. Both TAB and BFB finger weightings at frequencies higher than 20 Hz are greater than the ISO weighting.

Frequency weighting derived from power absorption of fingers-hand-arm system under z(h)-axis vibration.

PubMed

Dong, Ren G; Welcome, Daniel E; McDowell, Thomas W; Wu, John Z; Schopper, Aaron W

2006-01-01

The objectives of this study are to derive the frequency weighting from three vibration power absorption (VPA) methods (finger VPA, palm VPA, and total or hand VPA), and to explore whether these energy methods are better than the currently accepted acceleration method. To calculate the VPA weightings, the mechanical impedance of eight subjects exposed to a broadband random vibration spectrum in the z(h)-axis using 18 combinations of hand couplings and applied forces was measured. The VPA weightings were compared with the frequency weighting specified in ISO 5349-1 [2001. Mechanical Vibration--Measurement and Evaluation of Human Exposure to Hand--Transmitted Vibration--Part 1: General Requirements. International Organization for Standardization, Geneva, Switzerland]. This study found that the hand and palm VPA weightings are very similar to the ISO weighting but the finger VPA weighting for the combined grip and push action is much higher than the ISO weighting at frequencies higher than 25 Hz. Therefore, this study predicted that the total power absorption of the entire hand-arm system is likely to be correlated with psychophysical response or subjective sensation. However, if the ISO weighting method cannot yield good predictions of the vibration-induced disorders in the fingers and hand, the hand and palm energy methods are unlikely to yield significantly better predictions. The finger VPA is a vibration measure between unweighted and ISO weighted accelerations. The palm VPA method may have some value for studying the disorders in the wrist-arm system.

Role of Kv 4.3 in vibration-induced muscle pain in the rat

PubMed Central

Conner, Lindsay; Alvarez, Pedro; Bogen, Oliver; Levine, Jon D.

2015-01-01

We hypothesized that changes in the expression of Kv4.3 contribute to the mechanical hyperalgesia induced by vibration injury, a rodent model for hand-arm vibration syndrome in humans. Here we show that the exposure of the gastrocnemius muscle to vibration injury induces muscle hyperalgesia that is accompanied by a significant down-regulation of Kv4.3 in affected sensory nerve fibers in dorsal root ganglia (DRG). We additionally demonstrate that the intrathecal administration of antisense oligonucleotides for Kv4.3 mRNA itself induces muscle hyperalgesia in the rat. Our results suggest that attenuation in the expression of Kv4.3 may contribute to neuropathic pain in people affected by hand-arm vibration syndrome. PMID:26721612

Experiences and consequences for women with hand-arm vibration injuries.

PubMed

Bylund, Sonya Hörnqwist; Ahlgren, Christina

2010-01-01

Vibrating machines are used in a variety of occupations. Exposure to hand-arm vibration can cause vascular, neurological, and muscular symptoms in the hands and arms. This qualitative study provides a deeper understanding of the consequences of vibration injuries in women. In depth interviews were conducted with eight women with vibration injuries. The women were metal and wood product assemblers and dental personnel. The transcribed interviews were analyzed in accordance with the grounded theory method. The core category in the findings was "another life". This was constructed by the categories "consequences for everyday activities", "work performance", "household duties", "leisure", and "self perception" and shows that the injury had affected most parts of the women's lives and decreased their quality of life. The importance of well-functioning hands in all activities was highlighted. Reduced hand function due to numbness, muscle weakness, and pain caused restricted abilities to perform activities at work, at home, and during leisure time. The women described impact on their self-perception, as the injury had affected them in their roles as a worker, mother, and woman. The findings indicate that a vibration injury is a multidimensional problem that can affect every aspect of an individual's life. Health care providers should be aware of these complex consequences.

Aesthesiometric threshold changes over the course of a workshift in miners exposed to hand-arm vibration.

PubMed Central

Haines, T; Chong, J; Verrall, A B; Julian, J; Bernholz, C; Spears, R; Muir, D C

1988-01-01

The objective of this study was to investigate whether aesthesiometric threshold changes occur over the course of a workshift in vibration exposed hard rock miners relative to workers unexposed to vibration during the shift. The subjects were 99 miners and 40 smelter workers; four subjects declined to participate and nine were excluded from the analysis because of apparent failure to comprehend the testing procedure. Two point discrimination and depth sense aesthesiometry were conducted at the beginning and at the end of the workshift in all digits of both hands excluding the thumbs. In addition to the use of a vibrating tool during the shift, age, digital temperature, signs of arm injury, presence of fingertip callus, and handedness were documented. In the analysis the difference between postshift and preshift readings was studied in relation to these variables, particularly exposure to the jackleg drill during the shift. With the exception of exposure of the jackleg drill, no associations were observed between these variables and change over the workshift in aesthesiometric results, on both unadjusted comparison of means and backward elimination regression analysis. A statistically significant association, however, was found between the use of a jackleg drill and change in two point discrimination and in depth sense aesthesiometric results over the course of the shift, for the right hand. Evidence of the occurrence of a learning effect, particularly for two point discrimination aesthesiometry, was observed. The occurrence of an effect in the right, but not the left, hand reflects dominant handedness and relatively greater vibration exposure in the right hand in our subjects. This study supports the incorporation of an exposure free interval before aesthesiometric testing of vibration exposed workers. PMID:3342191

Hand-arm vibration syndrome and dose-response relation for vibration induced white finger among quarry drillers and stonecarvers. Italian Study Group on Physical Hazards in the Stone Industry.

PubMed Central

Bovenzi, M

1994-01-01

OBJECTIVES--To investigate the occurrence of disorders associated with the hand arm vibration syndrome in a large population of stone workers in Italy. The dose-response relation for vibration induced white finger (VWF) was also studied. METHODS--The study population consisted of 570 quarry drillers and stonecarvers exposed to vibration and 258 control stone workers who performed only manual activity. Each subject was interviewed with health and workplace assessment questionnaires. Sensorineural and VWF disorders were staged according to the Stockholm workshop scales. Vibration was measured on a representative sample of percussive and rotary tools. The 8 h energy equivalent frequency weighted acceleration (A (8)) and lifetime vibration doses were calculated for each of the exposed stone workers. RESULTS--Sensorineural and musculoskeletal symptoms occurred more frequently in the workers exposed to vibration than in the controls, but trend statistics did not show a linear exposure-response relation for these disorders. The prevalence of VWF was found to be 30.2% in the entire group exposed to vibration. Raynaud's phenomenon was discovered in 4.3% of the controls. VWF was strongly associated with exposure to vibration and a monotonic dose-response relation was found. According to the exposure data of this study, the expected percentage of stone workers affected with VWF tends to increase roughly in proportion to the square root of A(8) (for a particular exposure period) or in proportion to the square root of the duration of exposure (for a constant magnitude of vibration). CONCLUSION--Even although limited to a specific work situation, the dose-response relation for VWF estimated in this study suggests a time dependency such that halving the years of exposure allows a doubling of the energy equivalent vibration. According to these findings, the vibration exposure levels currently under discussion within the European Community seem to represent reasonable exposure limits for the protection of workers against the harmful effects of hand transmitted vibration. PMID:7951792

The apparent mass and mechanical impedance of the hand and the transmission of vibration to the fingers, hand, and arm

NASA Astrophysics Data System (ADS)

Concettoni, Enrico; Griffin, Michael

2009-08-01

Although hand-transmitted vibration causes injury and disease, most often evident in the fingers, the biodynamic responses of the fingers, hand, and arm are not yet well understood. A method of investigating the motion of the entire finger-hand-arm system, based on the simultaneous measurement of the biodynamic response at the driving point and the transmissibility to many points on the finger-hand-arm system, is illustrated. Fourteen male subjects participated in an experiment in which they pushed down on a vertically vibrating metal plate with their right forearm pronated and their elbow bent at 90°. The apparent mass and mechanical impedance of the finger-hand-arm system were measured for each of seven different contact conditions between the plate and the fingers and hand. Simultaneously, the vibration of the fingers, hand, and arm was measured at 41 locations using a scanning laser Doppler vibrometer. Transmissibilities showed how the vibration was transmitted along the arm and allowed the construction of spectral operating deflection shapes showing the vibration pattern of the fingers, hand, and arm for each of the seven contact conditions. The vibration patterns at critical frequencies for each contact condition have been used to explain features in the driving point biodynamic responses and the vibration behaviour of the hand-arm system. Spectral operating deflection shapes for the upper limb assist the interpretation of driving point biodynamic responses and help to advance understanding required to predict, explain, and control the various effects of hand-transmitted vibration.

Examining the Usefulness of ISO 10819 Anti-Vibration Glove Certification.

PubMed

Budd, Diandra; House, Ron

2017-03-01

Anti-vibration gloves are commonly worn to reduce hand-arm vibration exposure from work with hand-held vibrating tools when higher priority and more effective controls are unavailable. For gloves to be marketed as 'anti-vibration' they must meet the vibration transmissibility criteria described in the International Organization for Standardization (ISO) standard 10819 (2013). Several issues exist with respect to the methodology used for glove testing as well as the requirements for glove design and composition in ISO 10819 (2013). The true usefulness of anti-vibration gloves at preventing hand-arm vibration syndrome (HAVS) is controversial, given that their performance is dependent on tool vibration characteristics and the anthropometrics of workers in real working conditions. The major risk associated with the use of anti-vibration gloves is that it will give employees and employers a false sense of protection against the negative effects of hand-transmitted vibration. This commentary examines the limitations of the current international standards for anti-vibration glove testing and certification, thereby calling into question the degree of protection that anti-vibration gloves provide against HAVS, and cautioning users to consider both their benefits and potential drawbacks on a case-by-case basis. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

A method for analyzing absorbed power distribution in the hand and arm substructures when operating vibrating tools

NASA Astrophysics Data System (ADS)

Dong, Jennie H.; Dong, Ren G.; Rakheja, Subhash; Welcome, Daniel E.; McDowell, Thomas W.; Wu, John Z.

2008-04-01

In this study it was hypothesized that the vibration-induced injuries or disorders in a substructure of human hand-arm system are primarily associated with the vibration power absorption distributed in that substructure. As the first step to test this hypothesis, the major objective of this study is to develop a method for analyzing the vibration power flow and the distribution of vibration power absorptions in the major substructures (fingers, palm-hand-wrist, forearm and upper arm, and shoulder) of the system exposed to hand-transmitted vibration. A five-degrees-of-freedom model of the system incorporating finger- as well as palm-side driving points was applied for the analysis. The mechanical impedance data measured at the two driving points under four different hand actions involving 50 N grip-only, 15 N grip and 35 N push, 30 N grip and 45 N push, and 50 N grip and 50 N push, were used to identify the model parameters. The vibration power absorption distributed in the substructures were evaluated using vibration spectra measured on many tools. The frequency weightings of the distributed vibration power absorptions were derived and compared with the weighting defined in ISO 5349-1 (2001). This study found that vibration power absorption is primarily distributed in the arm and shoulder when operating low-frequency tools such as rammers, while a high concentration of vibration power absorption in the fingers and hand is observed when operating high-frequency tools, such as grinders. The vibration power absorption distributed in palm-wrist and arm is well correlated with the ISO-weighted acceleration, while the finger vibration power absorption is highly correlated with unweighted acceleration. The finger vibration power absorption-based frequency weighting suggested that exposure to vibration in the frequency range of 16-500 Hz could pose higher risks of developing finger disorders. The results support the use of the frequency weighting specified in the current standard for assessing risks of developing disorders in the palm-wrist-arm substructures. The standardized weighting, however, could overestimate low-frequency effects but greatly underestimate high-frequency effects on the development of finger disorders. The results are further discussed to show that the trends observed in the vibration power absorptions distributed in the substructures are consistent with some major findings of various physiological and epidemiological studies, which provides a support to the hypothesis of this study.

Hand-arm vibration in tropical rain forestry workers.

PubMed

Futatsuka, M; Inaoka, T; Ohtsuka, R; Sakurai, T; Moji, K; Igarashi, T

1995-01-01

Working conditions and health hazards including vibration syndrome related to forestry work using chain-saws were studied in Papua New Guinea and Indonesia. The subjects comprised 291 workers including 97 chain-saw operators. The health examination consisted of peripheral circulatory and sensory tests in the upper extremities. The vibration spectrum measured at the handle of the chain-saw indicated that these acceleration levels would lead to a moderately high risk of hand-arm vibration syndrome (HAVS). The peripheral circulatory function tests revealed dysfunction after more than five years vibration exposure. However, in general, the results of the function tests and subjective complaints showed fewer health problems compared to those of Japanese forestry workers. The reason of such differences of vibration effects seem to be the following: (1) warmer climate (more than 25 degrees C throughout the year), (2) young workers and short work experience. (3) short time vibration exposures on working days in the natural forests, (4) seasonal changes in logging work (5) healthy workers effects. Thus, we found no clear evidence that the workers of our study suffered from HAVS. A principal component analysis was applied. The factor score of the components of the reactive dynamics of peripheral circulation differed significantly after more than five years' exposure. On the other hand, we cannot deny the possibility that subclinical dysfunction of peripheral circulation may be caused by chain-saw operation in the tropics in future. Further investigations on the HAVS among forestry workers in the tropic environment are needed.

Reliability of a Malay-translated questionnaire for use in a hand-arm vibration syndrome study in Malaysia.

PubMed

Su, T A; Hoe, V C W

2008-12-01

Validity and reliability of the information relating to hand-transmitted vibration exposure and vibration-related health outcome are very important for case finding in hand-arm vibration syndrome (HAVS) studies. In a local HAVS study among a group of construction workers in Kuala Lumpur, Malaysia, a questionnaire translated into Malay was created based on the Hand-transmitted Vibration Health Surveillance--Initial Questionnaire and Clinical Assessment, from Vibration Injury Network. This study was conducted to determine the reliability of standardised questions in the questionnaire used in the study. 15 subjects were selected randomly from the sampling frame of the HAVS study. Test-retest reliability was conducted on all items contained in parts 1-6 of the questionnaire and clinical assessment form, with an interval of 13-14 days between the first and second administration. Kappa coefficient and percentage agreement were calculated for all standardised questions. The kappa coefficient and percentage agreement for all standardised questions varied from -0.174 to 1.000 and 66.7 to 100.0 percent, respectively. The kappa coefficient for important questions related to current vibratory tool usage, tingling, numbness and hand grip weakness were 0.714, 0.432, -0.077 and -0.120, respectively, while the percentage agreement for current vibratory tool usage, finger colour change, tingling, numbness and hand grip weakness were 85.7 percent, 92.8 percent, 79.5 percent, 85.7 percent and 71.4 percent, respectively. Intra-rater reliability on the extent of vibration exposure was good, with the intra-class correlation coefficient (95 percent confidence interval) ranging from 0.786 (0.334-0.931) to 0.975 (0.923-0.992). Critical questions on vascular, neurological and musculoskeletal symptoms of HAVS were found to be reliable. The history on the extent of vibration exposure revealed good reliability when explored by the investigator alone. This questionnaire is considered reliable to be used in the study of HAVS among construction workers working in a construction site.

Hand-arm Vibration Effects on Performance, Tactile Acuity, and Temperature of Hand

PubMed Central

Forouharmajd, Farhad; Yadegari, Mehrdad; Ahmadvand, Masoumeh; Forouharmajd, Farshad; Pourabdian, Siamak

2017-01-01

Effects of vibration appear as mechanical and psychological disorders, including stress reactions, cognitive and movement disorders, problem in concentration and paying attention to the assigned duties. The common signs and symptoms of hand-arm vibration (HAV) in the fingers and hands may appear as pins and needles feeling, tingling, numbness, and also the loss of finger sensation and dexterity. Laboratory Virtual Instrument Engineering Workbench programming software designed for occupational vibrations measurement was used to calculate HAV acceleration. Hole steadiness test is designed to measure involuntary movement of people. V-Pieron test is designed for one of the other aspects of the psycho motor phenomena of steadiness by moving the stylus across a V-form ruler. The two points test was an experiment of touch acuity, which used a caliper by placing the two styli very close on the pad of finger knuckles. The temperature of finger skin is also measured simultaneous to the above tests. Wilcoxon test indicated that a significant decrement in hand steadiness occurred after gripping a vibrating handle for 2 min (P ≤ 0.003). Wilcoxon test also represented a significant change in errors after gripping a grinder vibratory handle (P ≤ 0.003). The differences at all of the knuckles were significant with a confidence interval percentage of 99%. There was a significant reduction in finger skin temperature before and after exposure to vibration (mean = 0.45°C, based on paired sample test). The obtained results considerably demonstrated the relation between hand performance and vibrations due to gripping a grinder. It can be concluded that an injury or accident may happen after exposure to vibrations for the fine duties, in fast actions. PMID:29204383

Hand-arm Vibration Effects on Performance, Tactile Acuity, and Temperature of Hand.

PubMed

Forouharmajd, Farhad; Yadegari, Mehrdad; Ahmadvand, Masoumeh; Forouharmajd, Farshad; Pourabdian, Siamak

2017-01-01

Effects of vibration appear as mechanical and psychological disorders, including stress reactions, cognitive and movement disorders, problem in concentration and paying attention to the assigned duties. The common signs and symptoms of hand-arm vibration (HAV) in the fingers and hands may appear as pins and needles feeling, tingling, numbness, and also the loss of finger sensation and dexterity. Laboratory Virtual Instrument Engineering Workbench programming software designed for occupational vibrations measurement was used to calculate HAV acceleration. Hole steadiness test is designed to measure involuntary movement of people. V-Pieron test is designed for one of the other aspects of the psycho motor phenomena of steadiness by moving the stylus across a V-form ruler. The two points test was an experiment of touch acuity, which used a caliper by placing the two styli very close on the pad of finger knuckles. The temperature of finger skin is also measured simultaneous to the above tests. Wilcoxon test indicated that a significant decrement in hand steadiness occurred after gripping a vibrating handle for 2 min ( P ≤ 0.003). Wilcoxon test also represented a significant change in errors after gripping a grinder vibratory handle ( P ≤ 0.003). The differences at all of the knuckles were significant with a confidence interval percentage of 99%. There was a significant reduction in finger skin temperature before and after exposure to vibration (mean = 0.45°C, based on paired sample test). The obtained results considerably demonstrated the relation between hand performance and vibrations due to gripping a grinder. It can be concluded that an injury or accident may happen after exposure to vibrations for the fine duties, in fast actions.

The SOBANE strategy for the management of risk, as applied to whole-body or hand-arm vibration.

PubMed

Malchaire, J; Piette, A

2006-06-01

The objective was to develop a coherent set of methods to be used effectively in industry to prevent and manage the risks associated with exposure to vibration, by coordinating the progressive intervention of the workers, their management, the occupational health and safety (OHS) professionals and the experts. The methods were developed separately for the exposure to whole-body and hand-arm vibration. The SOBANE strategy of risk prevention includes four levels of intervention: level 1, Screening; level 2, Observation; level 3, Analysis and; level 4, Expertise. The methods making it possible to apply this strategy were developed for 14 types of risk factors. The article presents the methods specific to the prevention of the risks associated with the exposure to vibration. The strategy is similar to those published for the risks associated with exposure to noise, heat and musculoskeletal disorders. It explicitly recognizes the qualifications of the workers and their management with regard to the work situation and shares the principle that measuring the exposure of the workers is not necessarily the first step in order to improve these situations. It attempts to optimize the recourse to the competences of the OHS professionals and the experts, in order to come more rapidly, effectively and economically to practical control measures.

Hand-arm vibration syndrome in South African gold miners.

PubMed

Nyantumbu, Busi; Barber, Chris M; Ross, Mary; Curran, Andrew D; Fishwick, David; Dias, Belinda; Kgalamono, Spo; Phillips, James I

2007-01-01

Hand-arm vibration syndrome (HAVS) is associated with the use of hand-held vibrating tools. Affected workers may experience symptoms of tingling, numbness, loss of grip strength and pain. Loss of dexterity may impair everyday activities, and potentially increase the risk of occupational accidents. Although high vibration levels (up to 31 m/s(2)) have been measured in association with rock drills, HAVS has not been scientifically evaluated in the South African mining industry. The aim of this study was to determine the prevalence and severity of HAVS in South African gold miners, and to identify the tools responsible. A cross-sectional study was conducted in a single South African gold-mine. Participants were randomly selected from mineworkers returning from annual leave, comprising 156 subjects with occupational exposure to vibration, and 140 workers with no exposure. Miners who consented to participate underwent a clinical HAVS assessment following the UK Health and Safety Laboratory protocol. The prevalence of HAVS in vibration-exposed gold miners was 15%, with a mean latent period of 5.6 years. Among the non-exposed comparison group, 5% had signs and symptoms indistinguishable from HAVS. This difference was statistically significant (P < 0.05). All the cases of HAVS gave a history of exposure to rock drills. The study has diagnosed the first cases of HAVS in the South African mining industry. The prevalence of HAVS was lower than expected, and possible explanations for this may include a survivor population, and lack of vascular symptom reporting due to warm-ambient temperatures.

Vascular and nerve damage in workers exposed to vibrating tools. The importance of objective measurements of exposure time.

PubMed

Gerhardsson, Lars; Balogh, Istvan; Hambert, Per-Arne; Hjortsberg, Ulf; Karlsson, Jan-Erik

2005-01-01

The aim of the present study was to compare the development of vibration white fingers (VWF) in workers in relation to different ways of exposure estimation, and their relationship to the standard ISO 5349, annex A. Nineteen vibration exposed (grinding machines) male workers completed a questionnaire followed by a structured interview including questions regarding their estimated hand-held vibration exposure. Neurophysiological tests such as fractionated nerve conduction velocity in hands and arms, vibrotactile perception thresholds and temperature thresholds were determined. The subjective estimation of the mean daily exposure-time to vibrating tools was 192 min (range 18-480 min) among the workers. The estimated mean exposure time calculated from the consumption of grinding wheels was 42 min (range 18-60 min), approximately a four-fold overestimation (Wilcoxon's signed ranks test, p<0.001). Thus, objective measurements of the exposure time, related to the standard ISO 5349, which in this case were based on the consumption of grinding wheels, will in most cases give a better basis for adequate risk assessment than self-exposure assessment.

Can sensation of cold hands predict Raynaud's phenomenon or paraesthesia?

PubMed

Carlsson, D; Wahlström, J; Burström, L; Hagberg, M; Lundström, R; Pettersson, H; Nilsson, T

2018-05-10

Raynaud's phenomenon and neurosensory symptoms are common after hand-arm vibration exposure. Knowledge of early signs of vibration injuries is needed. To investigate the risk of developing Raynaud's phenomenon and paraesthesia in relation to sensation of cold hands in a cohort of male employees at an engineering plant. We followed a cohort of male manual and office workers at an engineering plant in Sweden for 21 years. At baseline (1987 and 1992) and each follow-up (1992, 1997, 2002, 2008), we assessed sensation of cold, Raynaud's phenomenon and paraesthesia in the hands using questionnaires and measured vibration exposure. We calculated risk estimates with univariate and multiple logistic regression analyses and adjusted for vibration exposure and tobacco usage. There were 241 study participants. During the study period, 21 individuals developed Raynaud's phenomenon and 43 developed paraesthesia. When adjusting the risk of developing Raynaud's phenomenon for vibration exposure and tobacco use, the odds ratios were between 6.0 and 6.3 (95% CI 2.2-17.0). We observed no increased risk for paraesthesia in relation to a sensation of cold hands. A sensation of cold hands was a risk factor for Raynaud's phenomenon. At the individual level, reporting a sensation of cold hands did not appear to be useful information to predict future development of Raynaud's phenomenon given a weak to moderate predictive value. For paraesthesia, the sensation of cold was not a risk factor and there was no predictive value at the individual level.

Vibration-reducing gloves: transmissibility at the palm of the hand in three orthogonal directions.

PubMed

McDowell, Thomas W; Dong, Ren G; Welcome, Daniel E; Xu, Xueyan S; Warren, Christopher

2013-01-01

Vibration-reducing (VR) gloves are commonly used as a means to help control exposures to hand-transmitted vibrations generated by powered hand tools. The objective of this study was to characterise the vibration transmissibility spectra and frequency-weighted vibration transmissibility of VR gloves at the palm of the hand in three orthogonal directions. Seven adult males participated in the evaluation of seven glove models using a three-dimensional hand-arm vibration test system. Three levels of hand coupling force were applied in the experiment. This study found that, in general, VR gloves are most effective at reducing vibrations transmitted to the palm along the forearm direction. Gloves that are found to be superior at reducing vibrations in the forearm direction may not be more effective in the other directions when compared with other VR gloves. This casts doubts on the validity of the standardised glove screening test. Practitioner Summary: This study used human subjects to measure three-dimensional vibration transmissibility of vibration-reducing gloves at the palm and identified their vibration attenuation characteristics. This study found the gloves to be most effective at reducing vibrations along the forearm direction. These gloves did not effectively attenuate vibration along the handle axial direction.

Diagnosis and treatment of hand-arm vibration syndrome and its relationship to carpal tunnel syndrome.

PubMed

Falkiner, Sonja

2003-07-01

Hand-arm vibration syndrome (HAVS) is a condition associated with the use of vibrating tools that occurs mainly in men. It consists primarily of 'occupational' Raynaud disease and digital polyneuropathy. Carpal tunnel syndrome (CTS) is also associated with hand transmitted vibration exposure and can coexist with HAVS. This article examines recent papers on causation, diagnosis, relationship to CTS and treatment. A Medline search was conducted, as was a search of UK, USA and Australian government occupational health and safety websites. Published papers that were single case studies or of poor design were not included. There are no 'gold standard' diagnostic tests for HAVS. It can mimic CTS in temperate climates and can occur with CTS. This is the diagnostic challenge when a male worker presents with apparent CTS symptoms. If he has worked with vibrating tools for many years, a diagnosis of HAVS or co-diagnosis of HAVS should be considered before a diagnosis of pure CTS is made. Nonwork risk factors for HAVS are predisposition, smoking, and exposure to vibration outside work. Cessation of exposure (and smoking) and redeployment is a critical part of treatment due to the dose response relationship of HAVS. This contrasts with adequately treated CTS, where the vast majority of workers can return to pre-injury duties. In severe cases, calcium antagonists are also used, but treatment is often ineffective. Few workplaces in Australia manage vibration risk or conduct screening to identify workers with early HAVS who should be redeployed. Local doctors have an important opportunity to diagnose HAVS and to make recommendations to the workplace on redeployment as part of treatment before symptoms become irreversible.

Vibration-induced multifocal neuropathy in forestry workers: electrophysiological findings in relation to vibration exposure and finger circulation.

PubMed

Bovenzi, M; Giannini, F; Rossi, S

2000-11-01

To investigate neural conduction in the upper limbs of symptomatic forestry workers with and without exposure to hand-transmitted vibration. A further aim was to assess the possible relationships between vibration exposure, nerve conduction and finger circulation in the forestry workers who used chain saws. A detailed neurophysiological investigation was performed on the upper extremities of 20 chain saw workers, 20 forestry operators with heavy manual work but without vibration exposure, and 20 healthy male controls. All subjects were screened to exclude polyneuropathy. Measurements of sensory and motor nerve conduction (velocity and amplitude) were obtained bilaterally from the median, ulnar and radial nerves. To assess peripheral vascular function, the forestry workers underwent a cold test with plethysmographic measurement of finger systolic blood pressure (FSBP). In the chain saw operators, vibration exposure was evaluated according to the International Standard ISO 5349. Indices of daily vibration exposure and lifetime cumulative vibration dose were estimated for each chain saw operator. Sensory nerve conduction in several segments of the median and radial nerves was significantly reduced in the chain saw operators compared with that in the workers doing heavy manual work and the controls. The neurophysiological pattern more frequently observed in the chain saw operators was a multifocal nerve conduction impairment to several neural segments with predominant involvement of sensory rather than motor fibres. Sensory nerve conduction velocities in the hands of the chain saw operators were inversely related to both daily and lifetime cumulative vibration exposures. In the vibration-exposed forestry workers, neither were sensori-motor complaints associated with vascular symptoms (finger whiteness) nor were electrophysiological data related to cold-induced changes in FSBP. Exposure to hand-transmitted vibration, in addition to ergonomic stress factors, can contribute to peripheral nerve disorders occurring in forestry workers who operate chain saws. The findings of this study suggest the existence of an exposure-effect relationship for vibration-induced neuropathy. Different underlying mechanisms are likely to be involved in the pathogenesis of the neurological and vascular components of the hand-arm vibration syndrome.

Epidemiological evidence for new frequency weightings of hand-transmitted vibration.

PubMed

Bovenzi, Massimo

2012-01-01

This paper provides an overview of the exposure-response relationship for the vascular component of the hand-arm vibration syndrome, called vibration-induced white finger (VWF). Over the past two decades, several epidemiological studies have shown a poor agreement between the risk for VWF observed in various occupational groups and that predicted by models included in annexes to International Standard ISO 5349 (ISO 5349:1986, ISO 5349-1:2001). Either overestimation or underestimation of the occurrence of VWF have been reported by investigators. It has been argued that the current ISO frequency-weighting curve for hand-transmitted vibration, which assumes that vibration-induced adverse health effects are inversely related to the frequency of vibration between 16 and 1250 Hz, may be unsuitable for the assessment of VWF. To investigate this issue, a prospective cohort study was carried out to explore the performance of four alternative frequency weightings for hand-transmitted vibration to predict the incidence of VWF in groups of forestry and stone workers. The findings of this study suggested that measures of vibration exposure which give relatively more weight to intermediate and high frequency vibration produced better predictions of the incidence of VWF than that obtained with the frequency weighting currently recommended in International Standard ISO 5349-1:2001.

Variability in hand-arm vibration during grinding operations.

PubMed

Liljelind, Ingrid; Wahlström, Jens; Nilsson, Leif; Toomingas, Allan; Burström, Lage

2011-04-01

Measurements of exposure to vibrations from hand-held tools are often conducted on a single occasion. However, repeated measurements may be crucial for estimating the actual dose with good precision. In addition, knowledge of determinants of exposure could be used to improve working conditions. The aim of this study was to assess hand-arm vibration (HAV) exposure during different grinding operations, in order to obtain estimates of the variance components and to evaluate the effect of work postures. Ten experienced operators used two compressed air-driven angle grinders of the same make in a simulated work task at a workplace. One part of the study consisted of using a grinder while assuming two different working postures: at a standard work bench (low) and on a wall with arms elevated and the work area adjusted to each operator's height (high). The workers repeated the task three times. In another part of the study, investigating the wheel wear, for each grinder, the operators used two new grinding wheels and with each wheel the operator performed two consecutive 1-min grinding tasks. Both grinding tasks were conducted on weld puddles of mild steel on a piece of mild steel. Measurements were taken according to ISO-standard 5349 [the equivalent hand-arm-weighted acceleration (m s(-2)) averaged over 1 min]. Mixed- and random-effects models were used to investigate the influence of the fixed variables and to estimate variance components. The equivalent hand-arm-weighted acceleration assessed when the task was performed on the bench and at the wall was 3.2 and 3.3 m s(-2), respectively. In the mixed-effects model, work posture was not a significant variable. The variables 'operator' and 'grinder' together explained only 12% of the exposure variability and 'grinding wheel' explained 47%; the residual variability of 41% remained unexplained. When the effect of grinding wheel wear was investigated in the random-effects model, 37% of the variability was associated with the wheel while minimal variability was associated with the operator or the grinder and 37% was unexplained. The interaction effect of grinder and operator explained 18% of the variability. In the wheel wear test, the equivalent hand-arm-weighted accelerations for Grinder 1 during the first and second grinding minutes were 3.4 and 2.9 m s(-2), respectively, and for Grinder 2, they were 3.1 and 2.9 m s(-2), respectively. For Grinder 1, the equivalent hand-arm-weighted acceleration during the first grinding minute was significantly higher (P = 0.04) than during the second minute. Work posture during grinding operations does not appear to affect the level of HAV. Grinding wheels explained much of the variability in this study, but almost 40% of the variance remained unexplained. The considerable variability in the equivalent hand-arm-weighted acceleration has an impact on the risk assessment at both the group and the individual level.

A cross sectional study on hand-arm vibration syndrome among a group of tree fellers in a tropical environment.

PubMed

Su, Anselm Ting; Maeda, Setsuo; Fukumoto, Jin; Miyai, Nobuyuki; Isahak, Marzuki; Yoshioka, Atsushi; Nakajima, Ryuichi; Bulgiba, Awang; Miyashita, Kazuhisa

2014-01-01

This study aimed to explore the clinical characteristics of hand arm vibration syndrome (HAVS) in a group of tree fellers in a tropical environment. We examined all tree fellers and selected control subjects in a logging camp of central Sarawak for vibration exposure and presence of HAVS symptoms utilizing vibrotactile perception threshold test (VPT) and cold water provocation test (CWP). None of the subjects reported white finger. The tree fellers reported significantly higher prevalence of finger coldness as compared to the control subjects (OR=10.32, 95%CI=1.21-87.94). A lower finger skin temperature, longer fingernail capillary return time and higher VPT were observed among the tree fellers as compared to the control subjects in all fingers (effect size >0.5). The VPT following CWP of the tree fellers was significantly higher (repeated measures ANOVA p=0.002, partial η(2)=0.196) than the control subject. The A (8) level was associated with finger tingling, numbness and dullness (effect size=0.983) and finger coldness (effect size=0.524) among the tree fellers. Finger coldness and finger tingling, numbness and dullness are important symptoms for HAVS in tropical environment that may indicate vascular and neurological damage due to hand-transmitted vibration exposure.

Associations of work activities requiring pinch or hand grip or exposure to hand-arm vibration with finger and wrist osteoarthritis: a meta-analysis.

PubMed

Hammer, Paula E C; Shiri, Rahman; Kryger, Ann I; Kirkeskov, Lilli; Bonde, Jens Peter

2014-03-01

We systematically reviewed the epidemiologic evidence linking finger and wrist osteoarthritis (OA) with work activities requiring pinch or hand grip or exposure to hand-arm vibration (HAV). PubMed and Embase databases were searched up to June 2013. We selected studies assessing the associations of radiographic diagnosed finger and/or wrist joint OA with work activities involving pinch or hand grip or exposure to HAV. We used specific criteria to evaluate completeness of reporting, potential confounding, and bias. Pooled odds ratios (OR) were computed using random-effects meta-analyses. Of the 19 studies included, 17 were cross-sectional, 1 was a prospective cohort, and 1 a case-control study. The meta-analyses of studies that controlled their estimates for at least age and gender showed the associations of pinch grip work with proximal interphalangeal joint [OR 1.56, 95% confidence interval (95% CI) 1.09-2.23] and the first carpometacarpal joint OA (OR 2.10, 95% CI 1.06-4.17), but not with distal interphalangeal, metacarpalphalangeal, or wrist joints OA. Hand grip work and exposure to HAV were not associated with any finger or wrist OA. Epidemiological studies provide limited evidence that pinch grip may increase the risk of wrist or finger OA, but causal relation cannot be resolved because of cross-sectional designs and inadequate characterization of biomechanical strain to the hand and wrist.

The Efficacy of Anti-vibration Gloves

PubMed Central

Hewitt, Sue; Dong, Ren; McDowell, Tom; Welcome, Daniel

2016-01-01

Anyone seeking to control the risks from vibration transmitted to the hands and arms may contemplate the use of anti-vibration gloves. To make an informed decision about any type of personal protective equipment, it is necessary to have performance data that allow the degree of protection to be estimated. The information provided with an anti-vibration glove may not be easy to understand without some background knowledge of how gloves are tested and does not provide any clear route for estimating likely protection. Some of the factors that influence the potential efficacy of an anti-vibration glove include how risks from hand–arm vibration exposure are assessed, how the standard test for a glove is carried out, the frequency range and direction of the vibration for which protection is sought, how much hand contact force or pressure is applied and the physical limitations due to glove material and construction. This paper reviews some of the background issues that are useful for potential purchasers of anti-vibration gloves. Ultimately, anti-vibration gloves cannot be relied on to provide sufficient and consistent protection to the wearer and before their use is contemplated all other available means of vibration control ought first to be implemented. PMID:27582615

Responses of sympathetic nervous system to cold exposure in vibration syndrome subjects and age-matched healthy controls.

PubMed

Nakamoto, M

1990-01-01

Plasma norepinephrine and epinephrine in vibration syndrome subjects and age-matched healthy controls were measured for the purpose of estimating the responsibility of the sympathetic nervous system to cold exposure. In preliminary experiment, it was confirmed that cold air exposure of the whole body was more suitable than one-hand immersion in cold water. In the main experiment, 195 subjects were examined. Sixty-five subjects had vibration syndrome with vibration-induced white finger (VWF + group) and 65 subjects had vibration syndrome without VWF (VWF- group) and 65 controls had no symptoms (control group). In the three groups, plasma norepinephrine levels increased during cold air exposure of whole body at 7 degrees +/- 1.5 degrees C. Blood pressure increased and skin temperature decreased during cold exposure. Percent increase of norepinephrine in the VWF+ group was the highest while that in VWF- group followed and that in the control group was the lowest. This whole-body response of the sympathetic nervous system to cold conditions reflected the VWF which are characteristic symptoms of vibration syndrome. Excluding the effects of shivering and a cold feeling under cold conditions, it was confirmed that the sympathetic nervous system in vibration syndrome is activated more than in the controls. These results suggest that vibration exposure to hand and arm affects the sympathetic nervous system.

Noise and hand-arm vibration exposure in relation to the risk of hearing loss.

PubMed

Pettersson, Hans; Burström, Lage; Hagberg, Mats; Lundström, Ronnie; Nilsson, Tohr

2012-01-01

The aim of this study was to examine the possible association of combined exposure of noise and hand-arm vibration (HAV) and the risk of noise-induced hearing loss. Workers in a heavy engineering industry were part of a dynamic cohort. Of these workers, 189 had HAV exposure, and their age and hearing status were recorded in the same year and were, therefore, included in the analysis. Data on HAV duration and acceleration was gathered through questionnaires, observations, and measurements. All available audiograms were categorized into normal and hearing loss. The first exposure variable included the lifetime HAV exposure. The lifetime HAV exposure was multiplied by the acceleration of HAV for the second and third exposure variable. Logistic regression using the Generalized Estimation Equations method was chosen to analyze the data to account for the repeated measurements. The analysis was performed with both continuous exposure variables and with exposure variables grouped into exposure quartiles with hearing loss as an outcome and age as a covariate. With continuous exposure variables, the odds ratio (OR) with a 95% confidence interval (CI) for hearing loss was equal to or greater than one for all exposure variables. When the exposure variables were grouped into quartiles, the OR with a 95% CI was greater than one at the third and fourth quartile. The results show that working with vibrating machines in an environment with noise exposure increases the risk of hearing loss, supporting an association between exposure to noise and HAV, and the noise-induced hearing loss.

Assessing the influence of antivibration glove on digital vascular responses to acute hand-arm vibration.

PubMed

Mahbub, Md H; Yokoyama, Kenjiro; Laskar, Md S; Inoue, Masaiwa; Takahashi, Yukio; Yamamoto, Shinji; Harada, Noriaki

2007-05-01

This study was designed to assess the influence of an antivibration glove on digital vascular responses in healthy subjects exposed to short-term grasping of a vibrating handle. To measure finger blood flow (FBF) and finger skin temperature (FST) once at the end of every min, a blood flowmeter sensor was attached to the dorsum and a thermistor sensor was attached to the medial surface of the subject's middle phalanx of the third finger of the right hand. After 5 min of baseline measurements without or with an antivibration glove meeting ISO standard 10819, worn on the right hand, subjects gripped a vibrating handle with the same hand for a period of 5 min. Vibration was generated at two frequencies of 31.5 Hz and 250 Hz with a frequency weighted rms acceleration of 5.5 m/s(2). FBF and FST continued to be recorded for a further 5 min after release of the vibrating handle. Statistical analysis showed no significant change after vibration exposure in either FST or FBF at 250 Hz, compared to baseline (control) measurements while using the antivibration glove. At 31.5 Hz, FBF data exhibited a significant difference between before and after grasping of vibrating handle, which was less under the condition of wearing the antivibration glove than under the condition of bare hand. The results provide evidence that the antivibration glove considerably influenced finger vascular changes in healthy subjects induced by vibration exposure, especially against high frequency vibration. Further studies are required to assess finger vascular responses to hand-transmitted vibration with antivibration gloves of different manufacturers.

Noise-induced hearing loss and combined noise and vibration exposure.

PubMed

Turcot, A; Girard, S A; Courteau, M; Baril, J; Larocque, R

2015-04-01

While there is a wide body of literature addressing noise-induced hearing loss (NIHL) and hand-arm vibration syndrome (HAVS) independently, relatively few studies have considered the combined effects of noise and vibration. These studies have suggested an increased risk of NIHL in workers with vibration white finger (VWF), though the relationship remains poorly understood. To determine whether hearing impairment is worse in noise-exposed workers with VWF than in workers with similar noise exposures but without VWF. The Quebec National Institute of Public Health audiometric database was used in conjunction with work-related accident and occupational diseases data from the Quebec workers' compensation board to analyse differences in audiometry results between vibration-exposed workers in the mining and forestry industries and the overall source population, and between mining and forestry workers with documented VWF and those without VWF. The International Organization for Standardization (ISO) 7029 standards were used to calculate hearing loss not attributable to age. 15751 vibration-exposed workers were identified in an overall source population of 59339. Workers with VWF (n = 96) had significantly worse hearing at every frequency studied (500, 1000, 2000 4000 Hz) compared with other mining and forestry workers without VWF. This study confirms previous findings of greater hearing loss at higher frequencies in workers with VWF, but also found a significant difference in hearing loss at low frequencies. It therefore supports the association between combined noise and hand-arm vibration (HAV) exposure and NIHL. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Vibration-reducing gloves: transmissibility at the palm of the hand in three orthogonal directions

PubMed Central

McDowell, Thomas W.; Dong, Ren G.; Welcome, Daniel E.; Xu, Xueyan S.; Warren, Christopher

2015-01-01

Vibration-reducing (VR) gloves are commonly used as a means to help control exposures to hand-transmitted vibrations generated by powered hand tools. The objective of this study was to characterise the vibration transmissibility spectra and frequency-weighted vibration transmissibility of VR gloves at the palm of the hand in three orthogonal directions. Seven adult males participated in the evaluation of seven glove models using a three-dimensional hand–arm vibration test system. Three levels of hand coupling force were applied in the experiment. This study found that, in general, VR gloves are most effective at reducing vibrations transmitted to the palm along the forearm direction. Gloves that are found to be superior at reducing vibrations in the forearm direction may not be more effective in the other directions when compared with other VR gloves. This casts doubts on the validity of the standardised glove screening test. Practitioner Summary This study used human subjects to measure three-dimensional vibration transmissibility of vibration-reducing gloves at the palm and identified their vibration attenuation characteristics. This study found the gloves to be most effective at reducing vibrations along the forearm direction. These gloves did not effectively attenuate vibration along the handle axial direction. PMID:24160755

New regression model for predicting hand-arm vibration (HAV) of Malaysian Army (MA) three-tonne truck steering wheels.

PubMed

Aziz, Shamsul Akmar Ab; Nuawi, Mohd Zaki; Nor, Mohd Jailani Mohd

2015-01-01

The objective of this study was to present a new method for determination of hand-arm vibration (HAV) in Malaysian Army (MA) three-tonne truck steering wheels based on changes in vehicle speed using regression model and the statistical analysis method known as Integrated Kurtosis-Based Algorithm for Z-Notch Filter Technique Vibro (I-kaz Vibro). The test was conducted for two different road conditions, tarmac and dirt roads. HAV exposure was measured using a Brüel & Kjær Type 3649 vibration analyzer, which is capable of recording HAV exposures from steering wheels. The data was analyzed using I-kaz Vibro to determine the HAV values in relation to varying speeds of a truck and to determine the degree of data scattering for HAV data signals. Based on the results obtained, HAV experienced by drivers can be determined using the daily vibration exposure A(8), I-kaz Vibro coefficient (Ƶ(v)(∞)), and the I-kaz Vibro display. The I-kaz Vibro displays also showed greater scatterings, indicating that the values of Ƶ(v)(∞) and A(8) were increasing. Prediction of HAV exposure was done using the developed regression model and graphical representations of Ƶ(v)(∞). The results of the regression model showed that Ƶ(v)(∞) increased when the vehicle speed and HAV exposure increased. For model validation, predicted and measured noise exposures were compared, and high coefficient of correlation (R(2)) values were obtained, indicating that good agreement was obtained between them. By using the developed regression model, we can easily predict HAV exposure from steering wheels for HAV exposure monitoring.

Evaluation of hand-arm and whole-body vibrations in construction and property management.

PubMed

Coggins, Marie A; Van Lente, Eric; McCallig, Margaret; Paddan, Gurmail; Moore, Ken

2010-11-01

To identify and measure the magnitude of hand-arm vibration (HAV) and whole-body vibration (WBV) sources (tools, vehicles etc.) in use within a previously unexamined sector: a construction and property management company. To evaluate the effect of factors such as age of tool, materials being worked on, number and location of tool handles, tool weight, and manufacturer brand on HAV magnitude and the effect of factors such as manufacturer machine brand, terrain, and work task on WBV magnitude. This study was carried out in a construction and property management company, employees (n = 469) working in the engineering services and maintenance departments who use vibrating equipment as part of their work were invited to participate. Two hundred and eighty-nine employees working as general operatives, excavator drivers, stone masons, carpenters, labourers, fitters, welders, and gardeners agreed to participate. A total of 20 types of hand tool (n = 264) and 11 types of vehicle (n = 158) in use within the company were selected for inclusion in the study. Five pieces of equipment had never previously been measured. Vibration measurements were carried out in accordance with ISO 5349-1 (Mechanical vibration-measurement and assessment of human exposure to hand transmitted vibration-Part 1: general guidance. 2001) (HAV) and ISO 2631-1 (Mechanical vibration and shock: evaluation of human exposure to WBV in the working environment. Part 1-general requirements. 1997) (WBV). Vibration measurements were made while workers were operating the equipment as part of their normal work activities. A wide range of vibration emission values were recorded for most tool types, e.g. orbital sanders (1.39-10.90 m s⁻²) and angle grinders (0.28-12.25 m s⁻²), and vehicle, e.g. forklifts (0.41-1.00 m s⁻²) and tractors (0.04-0.42 m s⁻²). Vibration magnitudes were largely consistent with those found in previous studies. The highest HAV magnitude was measured on a demolition hammer (13.3 m s⁻²) and the highest WBV magnitudes were measured on an excavator with a rock breaking attachment (5.81 m s⁻²). HAV magnitudes were found to be particularly strongly influenced by tool age, while WBV magnitudes varied with work activity and terrain. Within the construction and management company, few hand tools (3 of 20) exceeded the exposure action values (EAV) specified in the European Physical Agents (Vibration) Directive 2002/44/EC [On the minimum health and safety requirements regarding the exposure of works to the risks arising form physical agents (vibration)], when used for an 8-h period. HAV magnitudes were found to be very dependent on tool age, highlighting the importance of a tool maintenance programme incorporating tool work life prediction supported by regular vibration exposure measurements. Most of the vehicles (10 of 11) tested in this study exceeded the EAV specified for WBV, when operated for 8 h. WBV magnitudes were found to be dependent on the work task and thus, job rotation could be employed to control WBV exposures to acceptable levels.

Assessment of hand-transmitted vibration exposure from motorized forks used for beach-cleaning operations.

PubMed

McDowell, Thomas W; Welcome, Daniel E; Warren, Christopher; Xu, Xueyan S; Dong, Ren G

2013-01-01

Motorized vibrating manure forks were used in beach-cleaning operations following the massive Deepwater Horizon oil spill in the Gulf of Mexico during the summer of 2010. The objectives of this study were to characterize the vibration emissions of these motorized forks and to provide a first approximation of hand-transmitted vibration exposures to workers using these forks for beach cleaning. Eight operators were recruited to operate the motorized forks during this laboratory study. Four fork configurations were used in the study; two motor speeds and two fork basket options were evaluated. Accelerations were measured near each hand as the operators completed the simulated beach-cleaning task. The dominant vibration frequency for these tools was identified to be around 20 Hz. Because acceleration was found to increase with motor speed, workers should consider operating these tools with just enough speed to get the job done. These forks exhibited considerable acceleration magnitudes when unloaded. The study results suggest that the motor should not be operated with the fork in the unloaded state. Anti-vibration gloves are not effective at attenuating the vibration frequencies produced by these forks, and they may even amplify the transmitted vibration and increase hand/arm fatigue. While regular work gloves are suitable, vibration-reducing gloves may not be appropriate for use with these tools. These considerations may also be generally applicable for the use of motorized forks in other workplace environments.

An improved biomechanical model for simulating the strain of the hand-arm system under vibration stress.

PubMed

Fritz, M

1991-01-01

In order to define relationships between the vibration stress and the strain of the human hand-arm system a biomechanical model was developed. The four masses of the model representing the hand, the forearm and the upper arm were connected by dampers and springs in two perpendicular directions. Simulating muscle activity, damped torsion springs were included additionally. The motions of the model were described by a differential matrix equation which was solved by using a 'transfer matrix routine' as well as by numerical integration. Thus, functions with harmonic or transient time courses could be selected as an excitation. The simulated vibrations were compared with those of other hand-arm models. The forces and torques transmitted between the masses, and the energy dissipated by the dampers were computed for several combinations of exciter frequencies and accelerations. The dependence of torques upon excitation agreed fairly well with the behaviour of the arm muscles under vibration as described by various investigators. At frequencies above 100 Hz the energy was dissipated mainly by the dampers between the masses near to the exciter. Transferring this result to the hand-arm system it shows that at high frequencies energy is dissipated by the hand and its palmar tissues and this might be one cause for the incidence of vibration-induced white finger disease.

A method to quantify hand-transmitted vibration exposure based on the biodynamic stress concept.

PubMed

Dong, R G; Welcome, D E; Wu, J Z

2007-11-01

This study generally hypothesized that the vibration-induced biodynamic stress and number of its cycles in a substructure of the hand-arm system play an important role in the development of vibration-induced disorders in the substructure. As the first step to test this hypothesis, the specific aims of this study were to develop a practical method to quantify the biodynamic stress-cycle measure, to compare it with ISO-weighted and unweighted accelerations, and to assess its potential for applications. A mechanical-equivalent model of the system was established using reported experimental data. The model was used to estimate the average stresses in the fingers and palm. The frequency weightings of the stresses in these substructures were derived using the proposed stress-cycle measure. This study found the frequency dependence of the average stress distributed in the fingers is different from that in the palm. Therefore, this study predicted that the frequency dependencies of finger disorders could also be different from those of the disorders in the palm, wrist, and arms. If vibration-induced white finger (VWF) is correlated better with unweighted acceleration than with ISO-weighted acceleration, the biodynamic stress distributed in the fingers is likely to play a more important role in the development of VWF than is th e biodynamic stressdistributed in the other substructures of the hand-arm system. The results of this study also suggest that the ISO weighting underestimates the high-frequency effect on the finger disorder development but it may provide a reasonable risk assessment of the disorders in the wrist and arm.

A case report of vibration-induced hand comorbidities in a postwoman

PubMed Central

2011-01-01

Background Prolonged exposure to hand-transmitted vibration is associated with an increased occurrence of symptoms and signs of disorders in the vascular, neurological and osteoarticular systems of the upper limbs. However, the available epidemiological evidence is derived from studies on high vibration levels caused by vibratory tools, whereas little is known about possible upper limb disorders caused by chronic exposure to low vibration levels emitted by fixed sources. Case presentation We present the case of a postwoman who delivered mail for 15 years using a low-powered motorcycle. The woman was in good health until 2002, when she was diagnosed with bilateral Raynaud's phenomenon. In March 2003 a bilateral carpal tunnel syndrome was electromyographically diagnosed; surgical treatment was ineffective. Further examinations in 2005 highlighted the presence of chronic tendonitis (right middle finger flexor). Risk assessment From 1987, for 15 years, our patient rode her motorcycle for 4 h/day, carrying a load of 20-30 kg. For about a quarter of the time she drove over country roads. Using the information collected about the tasks carried out every day by the postwoman and some measurements performed on both handles of the motorcycle, as well as on both iron parts of the handlebars, we reconstructed the woman's previous exposure to hand-arm vibration. 8-hour energy-equivalent frequency weighted acceleration was about 2.4 m/s2. The lifetime dose was 1.5 × 109(m2/s4)hd. Conclusions The particular set of comorbidities presented by our patient suggests a common pathophysiological basis for all the diseases. Considering the level of exposure to vibrations and the lack of specific knowledge on the effects of vibration in women, we hypothesize an association between the work exposure and the onset of the diseases. PMID:21320318

[Carpal canal ultrasound examination in patients with mild hand-arm vibration disease].

PubMed

Liu, Y Z; Ye, Z H; Yang, W L; Zhu, J X; Lu, Q J; Su, W L

2016-08-20

Objective: To investigate the clinical value of ultrasound examination of carpal canal structure in patients with mild hand-arm vibration disease. Methods: A total of 29 patients (58 wrists) with mild hand-arm vibration disease who were treated in Shenzhen Prevention and Treatment Center for Occupational Diseases from May to December, 2015 were enrolled as observation group, and 20 healthy volunteers (40 wrists) were enrolled as the control group. Color Doppler ultrasound was used to observe the morphology and echo of the median nerve in the carpal canal and 9 muscle tendons and transverse carpal ligament. The thickness of transverse carpal ligament and diameter of the median nerve at the level of the hamulus of hamate bone were measured, as well as the cross-sectional area of the median nerve at the level of pisiform bone. Results: In the 29 patients with hand-arm vibration disease patients in the observation group, 8 experienced entrapment of the median nerve in the carpal canal, among whom 5 had entrapment in both wrists; there were 13 wrists (23%) with nerve entrapment and 45 wrists (77%) without nerve entrapment. Compared with the control group, the patients with hand-arm vibration disease and nerve entrapment in the observation group showed significant thickening of the transverse carpal ligament at the level of the hamulus of hamate bone and a significant increase in the cross-sectional area of the median nerve at the level of pisiform bone ( P <0.05) , while there were no significant differences in the thickness of transverse carpal ligament at the level of the hamulus of hamate bone and the cross-sectional area of the median nerve at the level of pisiform bone ( t=- 9.397 and -4.385, both P >0.05) . Conclusion: Ultrasound examination can clearly show the radiological changes of carpal canal contents in patients with mild hand-arm vibration disease and has a certain diagnostic value in nerve damage in patients with hand-arm vibration disease.

A systematic review of the etiopathogenesis of Kienböck's disease and a critical appraisal of its recognition as an occupational disease related to hand-arm vibration.

PubMed

Stahl, Stéphane; Stahl, Adelana Santos; Meisner, Christoph; Rahmanian-Schwarz, Afshin; Schaller, Hans-Eberhard; Lotter, Oliver

2012-11-21

We systematically reviewed etiological factors of Kienböck's disease (osteonecrosis of the lunate) discussed in the literature in order to examine the justification for including Kienböck's disease (KD) in the European Listing of Occupational Diseases. We searched the Ovid/Medline and the Cochrane Library for articles discussing the etiology of osteonecrosis of the lunate published since the first description of KD in 1910 and up until July 2012 in English, French or German. Literature was classified by the level of evidence presented, the etiopathological hypothesis discussed, and the author's conclusion about the role of the etiopathological hypothesis. The causal relationship between KD and hand-arm vibration was elucidated by the Bradford Hill criteria. A total of 220 references was found. Of the included 152 articles, 140 (92%) reached the evidence level IV (case series). The four most frequently discussed factors were negative ulnar variance (n=72; 47%), primary arterial ischemia of the lunate (n=63; 41%), trauma (n=63; 41%) and hand-arm vibration (n=53; 35%). The quality of the cohort studies on hand-arm vibration did not permit a meta-analysis to evaluate the strength of an association to KD. Evidence for the lack of consistency, plausibility and coherence of the 4 most frequently discussed etiopathologies was found. No evidence was found to support any of the nine Bradford Hill criteria for a causal relationship between KD and hand-arm vibration. A systematic review of 220 articles on the etiopathology of KD and the application of the Bradford Hill criteria does not provide sufficient scientific evidence to confirm or refute a causal relationship between KD and hand-arm vibration. This currently suggests that, KD does not comply with the criteria of the International Labour Organization determining occupational diseases. However, research with a higher level of evidence is required to further determine if hand-arm vibration is a risk factor for KD.

The physiological effects of simultaneous exposures to heat and vibration. Ph.D. Thesis - California Univ., Berkeley

NASA Technical Reports Server (NTRS)

Spaul, W. A.

1983-01-01

Determination of the effects of exposure to vibration on the body's ability to handle heat stress, and, if so, identification of the specific vibration parameters (frequency and intensity) for both whole-body (wbv) and segmental-body vibration (sbv) that would have the most detrimental effect on the body's ability to maintain thermal homeostasis were studied. Rectal and skin temperatures, heart rates, localized sweat rates, arm-segment blood perfusion rates, respiration rates, oxygen uptakes, and respiratory exchange ratios were measured in six men (22 to 33 yr) during simultaneous exposures to heat and vibration - either wbv or sbv, and during a heated 50 min recovery period. The heat conditions were T (sub db) = 43.5 + or - 0.5 C (mean + or S.E.M.), and RH = 20 + or - 4%. All vibration exposures were divided into two exposure conditions - identical frequencies but at a high intensity (HI) and a low intensity (LI) level. The HI wbv exposure was for 25 min/day at 5 Hz, 0.37 g-rms; 10 Hz, 0.46 g-rms; 16 Hz, 0.72 g-rms; 30 Hz, 1.40 g-rms; 80 Hz, 3.70 g-rms. The LI wbv exposure was for 2.5 hr/day at the same frequencies but at the following accelerations: 0.14 g-rms; 0.18 g-rms; 0.28 g-rms; 0.55 g-rms; 1.44 g-rms. During the sbv the subject stood and grasped a vibrating, in the Z-axis, hand grip with both hands.

Transcriptional Pathways Altered in Response to Vibration in a Model of Hand-Arm Vibration Syndrome.

PubMed

Waugh, Stacey; Kashon, Michael L; Li, Shengqiao; Miller, Gerome R; Johnson, Claud; Krajnak, Kristine

2016-04-01

The aim of this study was to use an established model of vibration-induced injury to assess frequency-dependent changes in transcript expression in skin, artery, and nerve tissues. Transcript expression in tissues from control and vibration-exposed rats (4 h/day for 10 days at 62.5, 125, or 250 Hz; 49 m/s, rms) was measured. Transcripts affected by vibration were used in bioinformatics analyses to identify molecular- and disease-related pathways associated with exposure to vibration. Analyses revealed that cancer-related pathways showed frequency-dependent changes in activation or inhibition. Most notably, the breast-related cancer-1 pathway was affected. Other pathways associated with breast cancer type 1 susceptibility protein related signaling, or associated with cancer and cell cycle/cell survivability were also affected. Occupational exposure to vibration may result in DNA damage and alterations in cell signaling pathways that have significant effects on cellular division.

Contact area affects frequency-dependent responses to vibration in the peripheral vascular and sensorineural systems.

PubMed

Krajnak, Kristine; Miller, G R; Waugh, Stacey

2018-01-01

Repetitive exposure to hand-transmitted vibration is associated with development of peripheral vascular and sensorineural dysfunctions. These disorders and symptoms associated with it are referred to as hand-arm vibration syndrome (HAVS). Although the symptoms of the disorder have been well characterized, the etiology and contribution of various exposure factors to development of the dysfunctions are not well understood. Previous studies performed using a rat-tail model of vibration demonstrated that vascular and peripheral nervous system adverse effects of vibration are frequency-dependent, with vibration frequencies at or near the resonant frequency producing the most severe injury. However, in these investigations, the amplitude of the exposed tissue was greater than amplitude typically noted in human fingers. To determine how contact with vibrating source and amplitude of the biodynamic response of the tissue affects the risk of injury occurring, this study compared the influence of frequency using different levels of restraint to assess how maintaining contact of the tail with vibrating source affects the transmission of vibration. Data demonstrated that for the most part, increasing the contact of the tail with the platform by restraining it with additional straps resulted in an enhancement in transmission of vibration signal and elevation in factors associated with vascular and peripheral nerve injury. In addition, there were also frequency-dependent effects, with exposure at 250 Hz generating greater effects than vibration at 62.5 Hz. These observations are consistent with studies in humans demonstrating that greater contact and exposure to frequencies near the resonant frequency pose the highest risk for generating peripheral vascular and sensorineural dysfunction.

Relationship between hand-arm vibration exposure and onset time for symptoms in a heavy engineering production workshop.

PubMed

Burström, Lage; Hagberg, Mats; Lundström, Ronnie; Nilsson, Tohr

2006-06-01

This study examined onset time for reported vascular and neurological symptoms in relation to the vibration load in a group of workers exposed to vibration. Information on the self-stated year for the first occurrence of symptoms was collected by means of questionnaires. During interviews data were obtained on self-stated estimations of daily exposure time, type of tool, and number of months or years with different exposures. The estimations of the vibration magnitudes of exposure were based on conducted measurements. From these data, the individual vibration exposure at the time of onset of symptoms was calculated. The incidence was 25.6 and 32.9 per 1000 exposure years for vascular and neurological symptoms, respectively, in the group of workers. The first onset of symptoms appeared after an average of 12 years of exposure. For the workers, the symptoms of vascular or neurological disorders started after about the same number of exposure years. The calculated accumulated acceleration correlated best with the onset time of symptoms. It was concluded that, since the workers' exposure to vibration was below the action level established in the European vibration directive, the results suggest that the action level is not a safe level for avoiding vascular and neurological symptoms.

[Clinical features of the hand-arm vibration syndrome in miners].

PubMed

Kákosy, Tibor; Németh, László; Kiss, Gábor; Lászlóffy, Marianna; Kardos, Kálmán

2006-05-07

It is well known that the vibrating tools used by the miners can cause hand-arm vibration syndrome. However no detailed reports on this field could be found in the Hungarian literature. The aim of this study was to clarify the clinical features of the hand-arm vibration syndrome of the miners. The circulation, the peripheral nerves and the osteoarticular system of the upper extremities of 152 miners were examined by means of cold provocation test, Allen-test, measurement of systolic blood pressure performed by Doppler flowmeter, clinical neurological and neurographic examination and X-ray investigation of the bones and joints. Hand-arm vibration syndrome was diagnosed in 87 patients (57.2%). The most common symptom was the lesion of the circulation which occurred in 78 patients (89.6%). The peripheral nerves were affected in 44 cases (50.5%). Radiological alteration of the bones and joints of the upper extremities was observed in 32 patients (36.8%). Out of 78 damaged cases the frequency of the vascular diseases was as follows: angiopathy (diminished systolic blood pressure in the fingers): 66 patient (84.6%), occlusion of the hand arteries (positive Allen-test) and arterial form of the thoracic outlet syndrome (positive elevation-test) respectively: 28 and 28 cases (35.9%), Raynaud phenomenon (positive cold-provocation test): 26 cases (33.3%). The peripheral nerves were examined in detail in 141 cases. Pathological alterations were observed in 78 patients (55.3%) in the following forms: carpal tunnel syndrome: 66 cases (84.6%), peripheral neuropathy of the upper limbs: 20 patients (25.6%), lesion of the ulnar nerve: 3 cases (3.8%), brachial plexus lesion: one patient (1.3%). Radiological alteration was most common in the carpal region (87 cases, 57.2%). The frequency of the lesion of cubital (40.4%) and shoulder region (40.7%) was practically the same. In the carpal region the most common alterations were the degenerative processes (23 cases, 15.1%) followed by the aseptic osteonecroses (22 patients, 14.5%). In the cubital region the periarticular changes (31 patients, 23.9%) were most common followed by degenerative changes (21 cases, 16.2%) and the osteochondrosis dissecans (13 cases, 10.1%). In the shoulder region the degenerative processes were the most common changes (41 patients, 34.7%), first of all in the acromioclavicular joint (21 cases, 17.8%). Aseptic necrosis was observed in two patients. The miners are professionally exposed not only to hand-arm vibration, but also to increased physical stress. The symptoms on the upper limbs can develop as the result of both exposures.

A two scale modeling and computational framework for vibration-induced Raynaud syndrome.

PubMed

Hua, Yue; Lemerle, Pierre; Ganghoffer, Jean-François

2017-07-01

Hand-Arm Vibration syndrome (HAVS), usually caused by long-term use of hand-held power tools, can in certain manifestations alter the peripheral blood circulation in the hand-arm region. HAVS typically occurs after exposure to cold, causing an abnormally strong vasoconstriction of blood vessels. A pathoanatomical mechanism suggests that a reduction of the lumen of the blood vessels in VWF (Vibration White Finger) subjects, due to either hypertrophy or thickening of the vessel wall, may be at the origin of the disease. However, the direct and indirect effects of the load of the hand-held tools on the structure of blood vessels remain controversial:.one hypothesis is the mechanical action of vibration on the local acral dysregulation and/or on the vessel histomorphological modifications. Another hypothesis is the participation of the sympathetic nervous system to this dysregulation. In this paper, we assume the modifications as mechanobiological growth and the load-effect relationship may be interpreted as directly or indirectly induced. This work is the first attempt to model the effect of vibration through soft tissues onto the distal capillaries, addressing the double paradigm of multi space-time scales, i.e. low period vibration versus high time constant of the growth phenomenon as well as vibrations propagating in the macroscopic tissue including the microscopic capillary structures subjected to a pathological microstructural evolution. The objective is to lay down the theoretical basis of growth modeling for the small distal artery, with the ability to predict the geometrical and structural changes of the arterial walls caused by vibration exposure. We adopt the key idea of splitting the problem into one global vibration problem at the macroscopic scale and one local growth problem at the micro level. The macroscopic hyperelastic viscous dynamic model of the fingertip cross-section is validated by fitting experimental data. It is then used in steady-state vibration conditions to predict the mechanical fields in the close vicinity of capillaries. The space scale transfer from macroscopic to microscopic levels is ensured by considering a representative volume element (RVE) embedding a single capillary in its center. The vibrations emitted by the hand held power tool are next linked to the capillary growth through the adopted biomechanical growth model at the capillary level. The obtained results show that vibrations induce an increase of the thickness of the capillary's wall, thereby confirming the scenario of vibrations induced reduction of the lumen of blood vessels. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Tendon Vibration on Hemiparetic Arm Stability in Unstable Workspaces.

PubMed

Conrad, Megan O; Gadhoke, Bani; Scheidt, Robert A; Schmit, Brian D

2015-01-01

Sensory stimulation of wrist musculature can enhance stability in the proximal arm and may be a useful therapy aimed at improving arm control post-stroke. Specifically, our prior research indicates tendon vibration can enhance stability during point-to-point arm movements and in tracking tasks. The goal of the present study was to investigate the influence of forearm tendon vibration on endpoint stability, measured at the hand, immediately following forward arm movements in an unstable environment. Both proximal and distal workspaces were tested. Ten hemiparetic stroke subjects and 5 healthy controls made forward arm movements while grasping the handle of a two-joint robotic arm. At the end of each movement, the robot applied destabilizing forces. During some trials, 70 Hz vibration was applied to the forearm flexor muscle tendons. 70 Hz was used as the stimulus frequency as it lies within the range of optimal frequencies that activate the muscle spindles at the highest response rate. Endpoint position, velocity, muscle activity and grip force data were compared before, during and after vibration. Stability at the endpoint was quantified as the magnitude of oscillation about the target position, calculated from the power of the tangential velocity data. Prior to vibration, subjects produced unstable, oscillating hand movements about the target location due to the applied force field. Stability increased during vibration, as evidenced by decreased oscillation in hand tangential velocity.

Effect of Tendon Vibration on Hemiparetic Arm Stability in Unstable Workspaces

PubMed Central

Conrad, Megan O.; Gadhoke, Bani; Scheidt, Robert A.; Schmit, Brian D.

2015-01-01

Sensory stimulation of wrist musculature can enhance stability in the proximal arm and may be a useful therapy aimed at improving arm control post-stroke. Specifically, our prior research indicates tendon vibration can enhance stability during point-to-point arm movements and in tracking tasks. The goal of the present study was to investigate the influence of forearm tendon vibration on endpoint stability, measured at the hand, immediately following forward arm movements in an unstable environment. Both proximal and distal workspaces were tested. Ten hemiparetic stroke subjects and 5 healthy controls made forward arm movements while grasping the handle of a two-joint robotic arm. At the end of each movement, the robot applied destabilizing forces. During some trials, 70 Hz vibration was applied to the forearm flexor muscle tendons. 70 Hz was used as the stimulus frequency as it lies within the range of optimal frequencies that activate the muscle spindles at the highest response rate. Endpoint position, velocity, muscle activity and grip force data were compared before, during and after vibration. Stability at the endpoint was quantified as the magnitude of oscillation about the target position, calculated from the power of the tangential velocity data. Prior to vibration, subjects produced unstable, oscillating hand movements about the target location due to the applied force field. Stability increased during vibration, as evidenced by decreased oscillation in hand tangential velocity. PMID:26633892

Vibration energy absorption (VEA) in human fingers-hand-arm system.

PubMed

Dong, R G; Schopper, A W; McDowell, T W; Welcome, D E; Wu, J Z; Smutz, W P; Warren, C; Rakheja, S

2004-07-01

A methodology for measuring the vibration energy absorbed into the fingers and the palm exposed to vibration is proposed to study the distribution of the vibration energy absorption (VEA) in the fingers-hand-arm system and to explore its potential association with vibration-induced white finger (VWF). The study involved 12 adult male subjects, constant-velocity sinusoidal excitations at 10 different discrete frequencies in the range of 16-1000 Hz, and four different hand-handle coupling conditions (finger pull-only, hand grip-only, palm push-only, and combined grip and push). The results of the study suggest that the VEA into the fingers is considerably less than that into the palm at low frequencies (< or = 25 Hz). They are, however, comparable under the excitations in the 250-1000 Hz frequency range. The finger VEA at high frequencies (> or = 100 Hz) is practically independent of the hand-handle coupling condition. The coupling conditions affect the VEA into the fingers and the palm very differently. The finger VEA results suggest that the ISO standardized frequency weighting (ISO 5349-1, 2001) may underestimate the effect of high frequency vibration on vibration-induced finger disorders. The proposed method may provide new opportunities to examine VEA and its association with VWF and other types of vibration-induced disorders in the hand-arm system.

Ergonomic analysis of fastening vibration based on ISO Standard 5349 (2001).

PubMed

Joshi, Akul; Leu, Ming; Murray, Susan

2012-11-01

Hand-held power tools used for fastening operations exert high dynamic forces on the operator's hand-arm, potentially causing injuries to the operator in the long run. This paper presents a study that analyzed the vibrations exerted by two hand-held power tools used for fastening operations with the operating exhibiting different postures. The two pneumatic tools, a right-angled nut-runner and an offset pistol-grip, are used to install shearing-type fasteners. A tri-axial accelerometer is used to measure the tool's vibration. The position and orientation of the transducer mounted on the tool follows the ISO-5349 Standard. The measured vibration data is used to compare the two power tools at different operating postures. The data analysis determines the number of years required to reach a 10% probability of developing finger blanching. The results indicate that the pistol-grip tool induces more vibration in the hand-arm than the right-angled nut-runner and that the vibrations exerted on the hand-arm vary for different postures. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Tool-specific performance of vibration-reducing gloves for attenuating palm-transmitted vibrations in three orthogonal directions

PubMed Central

Dong, Ren G.; Welcome, Daniel E.; Peterson, Donald R.; Xu, Xueyan S.; McDowell, Thomas W.; Warren, Christopher; Asaki, Takafumi; Kudernatsch, Simon; Brammer, Antony

2015-01-01

Vibration-reducing (VR) gloves have been increasingly used to help reduce vibration exposure, but it remains unclear how effective these gloves are. The purpose of this study was to estimate tool-specific performances of VR gloves for reducing the vibrations transmitted to the palm of the hand in three orthogonal directions (3-D) in an attempt to assess glove effectiveness and aid in the appropriate selection of these gloves. Four typical VR gloves were considered in this study, two of which can be classified as anti-vibration (AV) gloves according to the current AV glove test standard. The average transmissibility spectrum of each glove in each direction was synthesized based on spectra measured in this study and other spectra collected from reported studies. More than seventy vibration spectra of various tools or machines were considered in the estimations, which were also measured in this study or collected from reported studies. The glove performance assessments were based on the percent reduction of frequency-weighted acceleration as is required in the current standard for assessing the risk of vibration exposures. The estimated tool-specific vibration reductions of the gloves indicate that the VR gloves could slightly reduce (<5%) or marginally amplify (<10%) the vibrations generated from low-frequency (<25 Hz) tools or those vibrating primarily along the axis of the tool handle. With other tools, the VR gloves could reduce palm-transmitted vibrations in the range of 5%–58%, primarily depending on the specific tool and its vibration spectra in the three directions. The two AV gloves were not more effective than the other gloves with some of the tools considered in this study. The implications of the results are discussed. Relevance to industry Hand-transmitted vibration exposure may cause hand-arm vibration syndrome. Vibration-reducing gloves are considered as an alternative approach to reduce the vibration exposure. This study provides useful information on the effectiveness of the gloves when used with many tools for reducing the vibration transmitted to the palm in three directions. The results can aid in the appropriate selection and use of these gloves. PMID:26726275

Effective information campaign for management of exposure to hand-arm vibration in the metal and construction industries.

PubMed

Sauni, Riitta; Toivio, Pauliina; Esko, Toppila; Pääkkönen, Rauno; Uitti, Jukka

2015-01-01

European Directive 2002/44/EC defines employers' responsibilities in the risk management of hand-arm vibration (HAV). However, the directive is still not completely implemented in all risk industries. The aim of our study was to determine whether it is possible to improve the recognition and management of the risks of HAV at workplaces with a one-year information campaign. A questionnaire on opinions and measures for controlling HAV exposure at workplaces was sent to all occupational safety representatives and occupational safety managers in the construction and metal industry in Finland (n=1887) and once again to those who responded to the first questionnaire (n=961) one year after the campaign. The campaign increased recognition of HAV in risk assessment from 57.0% to 68.3% (p=.001), increased measures to decrease exposure to HAV from 54.6% to 64.2% (p=.006) and increased the number of programmes to control the risks due to HAV (p<.001). The information campaign, which focuses on the construction and metal industries, proved to be effective in increasing the awareness of the risks of HAV and the measures needed to control exposure to HAV. A similar campaign can be recommended in the case of risks specific to certain occupations.

Test-retest reliability of neurophysiological tests of hand-arm vibration syndrome in vibration exposed workers and unexposed referents.

PubMed

Gerhardsson, Lars; Gillström, Lennart; Hagberg, Mats

2014-01-01

Exposure to hand-held vibrating tools may cause the hand-arm vibration syndrome (HAVS). The aim was to study the test-retest reliability of hand and muscle strength tests, and tests for the determination of thermal and vibration perception thresholds, which are used when investigating signs of neuropathy in vibration exposed workers. In this study, 47 vibration exposed workers who had been investigated at the department of Occupational and Environmental Medicine in Gothenburg were compared with a randomized sample of 18 unexposed subjects from the general population of the city of Gothenburg. All participants passed a structured interview, answered several questionnaires and had a physical examination including hand and finger muscle strength tests, determination of vibrotactile (VPT) and thermal perception thresholds (TPT). Two weeks later, 23 workers and referents, selected in a randomized manner, were called back for the same test-procedures for the evaluation of test-retest reliability. The test-retest reliability after a two week interval expressed as limits of agreement (LOA; Bland-Altman), intra-class correlation coefficients (ICC) and Pearson correlation coefficients was excellent for tests with the Baseline hand grip, Pinch-grip and 3-Chuck grip among the exposed workers and referents (N = 23: percentage of differences within LOA 91 - 100%; ICC-values ≥0.93; Pearson r ≥0.93). The test-retest reliability was also excellent (percentage of differences within LOA 96-100 %) for the determination of vibration perception thresholds in digits 2 and 5 bilaterally as well as for temperature perception thresholds in digits 2 and 5, bilaterally (percentage of differences within LOA 91 - 96%). For ICC and Pearson r the results for vibration perception thresholds were good for digit 2, left hand and for digit 5, bilaterally (ICC ≥ 0.84; r ≥0.85), and lower (ICC = 0.59; r = 0.59) for digit 2, right hand. For the latter two indices the test-retest reliability for the determination of temperature thresholds was lower and showed more varying results. The strong test-retest reliability for hand and muscle strength tests as well as for the determination of VPTs makes these procedures useful for diagnostic purposes and follow-up studies in vibration exposed workers.

Vibration on board and health effects.

PubMed

Jensen, Anker; Jepsen, Jørgen Riis

2014-01-01

There is only limited knowledge of the exposure to vibrations of ships' crews and their risk of vibration-induced health effects. Exposure to hand-arm vibrations from the use of vibrating tools at sea does not differ from that in the land-based trades. However, in contrast to most other work places, seafarers are also exposed to vibrations to the feet when standing on vibrating surfaces on board. Anecdotal reports have related the development of "white feet" to local exposure to vibration, e.g. in mining, but this connection has not been investigated in the maritime setting. As known from studies of the health consequences of whole body vibrations in land-transportation, such exposure at sea may affect ships' passengers and crews. While the relation of back disorders to high levels of whole body vibration has been demonstrated among e.g. tractor drivers, there are no reported epidemiological evidence for such relation among seafarers except for fishermen, who, however, are also exposed to additional recognised physical risk factors at work. The assessment and reduction of vibrations by naval architects relates to technical implications of this impact for the ships' construction, but has limited value for the estimation of health risks because they express the vibration intensity differently that it is done in a medical context.

A systematic review of the etiopathogenesis of Kienböck's disease and a critical appraisal of its recognition as an occupational disease related to hand-arm vibration

PubMed Central

2012-01-01

Background We systematically reviewed etiological factors of Kienböck’s disease (osteonecrosis of the lunate) discussed in the literature in order to examine the justification for including Kienböck’s disease (KD) in the European Listing of Occupational Diseases. Methods We searched the Ovid/Medline and the Cochrane Library for articles discussing the etiology of osteonecrosis of the lunate published since the first description of KD in 1910 and up until July 2012 in English, French or German. Literature was classified by the level of evidence presented, the etiopathological hypothesis discussed, and the author's conclusion about the role of the etiopathological hypothesis. The causal relationship between KD and hand-arm vibration was elucidated by the Bradford Hill criteria. Results A total of 220 references was found. Of the included 152 articles, 140 (92%) reached the evidence level IV (case series). The four most frequently discussed factors were negative ulnar variance (n=72; 47%), primary arterial ischemia of the lunate (n=63; 41%), trauma (n=63; 41%) and hand-arm vibration (n=53; 35%). The quality of the cohort studies on hand-arm vibration did not permit a meta-analysis to evaluate the strength of an association to KD. Evidence for the lack of consistency, plausibility and coherence of the 4 most frequently discussed etiopathologies was found. No evidence was found to support any of the nine Bradford Hill criteria for a causal relationship between KD and hand-arm vibration. Conclusions A systematic review of 220 articles on the etiopathology of KD and the application of the Bradford Hill criteria does not provide sufficient scientific evidence to confirm or refute a causal relationship between KD and hand-arm vibration. This currently suggests that, KD does not comply with the criteria of the International Labour Organization determining occupational diseases. However, research with a higher level of evidence is required to further determine if hand-arm vibration is a risk factor for KD. PMID:23171057

Do exposure limits for hand-transmitted vibration prevent carpal tunnel syndrome?

PubMed

Gillibrand, S; Ntani, G; Coggon, D

2016-07-01

An apparently high frequency of carpal tunnel syndrome (CTS) among shipyard workers undergoing health surveillance because of exposure to hand-transmitted vibration (HTV) prompted concerns that current regulatory limits on exposure might not protect adequately against the disorder. To explore whether within regulatory limits, higher exposures to HTV predispose to CTS. As part of a retrospective audit, we compared duration and current intensity of exposure to HTV in cases with new-onset CTS and controls matched for age. Conditional logistic regression was used to quantify associations, which were summarized by odds ratios (ORs) and 95% confidence intervals (CIs). There were 23 cases and 55 controls. After adjustment for body mass index and previous diagnosis of diabetes, no clear associations were observed either with duration of exposure to HTV or with current intensity of exposure. Risk was non-significantly elevated in men with ≥30 years' exposure to HTV (OR 1.6), but in the highest category of current exposure [8-h energy-equivalent frequency-weighted acceleration (A8) ≥ 4.0 m/s(2)], risk was lower than that in the reference category (A8 < 2.5 m/s(2)). Moreover, there was a significantly reduced risk of CTS in men with a previous diagnosis of hand-arm vibration syndrome (HAVS) (OR 0.2, 95% CI 0.1-0.9). We found no evidence that below the current limit for A(8) of 5 m/s(2), higher exposures to HTV predispose to CTS. However, care should be taken not to overlook the possibility of treatable CTS when workers with diagnosed HAVS present with new or worsening sensory symptoms in the hand. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Nailfold capillary morphological characteristics of hand-arm vibration syndrome: a cross-sectional study

PubMed Central

Chen, QingSong; Chen, GuiPing; Xiao, Bin; Lin, HanSheng; Qu, HongYing; Zhang, DanYing; Shi, MaoGong; Lang, Li; Yang, Bei; Yan, MaoSheng

2016-01-01

Objective The purpose of this study was to investigate the characteristics of nailfold capillaroscopy associated with hand-arm vibration syndrome (HAVS). Methods In total, 113 male gold miners were recruited: 35 workers who were chronically exposed to vibration and developed vibration-induced white finger were defined as the HAVS group, 39 workers who were exposed to vibration but did not have HAVS were classified as the vibration-exposed controls (VEC) group, and 39 workers without vibration exposure were categorised as the non-VEC (NVEC) group. Video capillaroscopy was used to capture images of the 2nd, 3rd and 4th fingers of both hands. The following nailfold capillary characteristics were included: number of capillaries/mm, avascular areas, haemorrhages and enlarged capillaries. The experiments were carried out in the same winter. All characteristics were evaluated under blinded conditions. Results Significant differences in all morphological characteristics existed between the groups (p<0.05). Avascular areas in the HAVS, VEC and NVEC groups appeared in 74.3%, 43.6% and 25.0% of participants, respectively. A higher percentage of participants had haemorrhages in the HAVS group (65.7%) compared with the other groups (VEC: 7.7% and NVEC: 7.5%). The number of capillaries/mm, input limb width, output limb width, apical width, and ratio of output limb and input limb all had more than 70% sensitivity or specificity of their cut-off value. Conclusions Nailfold capillary characteristics, especially the number of capillaries/mm, avascular areas, haemorrhages, output limb width, input limb width and apical width alterations, revealed significant associations with HAVS. PMID:27888176

A comparison of different vibration exercise techniques on neuromuscular performance.

PubMed

García-Gutiérrez, M T; Rhea, M R; Marín, P J

2014-09-01

The first purpose of this study was to determine the effects of whole-body vibration (WBV) exercise during an isometric hand-grip exercise. The second purpose was to evaluate whether more than one vibratory focus would evoke an increase in the effects evoked by only one vibratory focus. The present study investigated whether WBV exposure during 10 repetitions of a handgrip dynamometer while standing on a WBV platform. Twenty-eight recreationally active university students completed 3 different test conditions, in random order: 1) grip dynamometer exercise with superimposed WBV and contralateral arm vibration (WBV+AV); 2) superimposed arm vibration only (AV); 3) grip dynamometer exercise without vibration (Control). The hand grip strength was slightly higher in the WBV condition as compared to the Control and AV conditions (1.1% and 3.6%, p>0.05, respectively). A main effect of the EMGrms of extensor digitorum muscle (ED) was observed indicating that the WBV+AV condition produced a lower co-activation of ED during a flexor digital task than the Control and AV (p<0.05) conditions. The application of WBV+AV may acutely increase muscle coordination and decreases the coactivation of ED. Furthermore, the muscle EMGrms showed increases in activation near the vibratory focus in both upper- and lower-body.

Transcriptional Pathways Altered in Response to Vibration in a Model of Hand-Arm Vibration Syndrome

PubMed Central

Waugh, Stacey; Kashon, Michael L.; Li, Shengqiao; Miller, Gerome R.; Johnson, Claud; Krajnak, Kristine

2016-01-01

Objective The aim of this study was to use an established model of vibration-induced injury to assess frequency-dependent changes in transcript expression in skin, artery, and nerve tissues. Methods Transcript expression in tissues from control and vibration-exposed rats (4 h/day for 10 days at 62.5, 125, or 250 Hz; 49 m/s2, rms) was measured. Transcripts affected by vibration were used in bioinformatics analyses to identify molecular- and disease-related pathways associated with exposure to vibration. Results Analyses revealed that cancer-related pathways showed frequency-dependent changes in activation or inhibition. Most notably, the breast-related cancer-1 pathway was affected. Other pathways associated with breast cancer type 1 susceptibility protein related signaling, or associated with cancer and cell cycle/cell survivability were also affected. Conclusion Occupational exposure to vibration may result in DNA damage and alterations in cell signaling pathways that have significant effects on cellular division. PMID:27058473

Hand-arm vibration syndrome: A rarely seen diagnosis.

PubMed

Campbell, Rebecca A; Janko, Matthew R; Hacker, Robert I

2017-06-01

Hand-arm vibration syndrome (HAVS) is a collection of sensory, vascular, and musculoskeletal symptoms caused by repetitive trauma from vibration. This case report demonstrates how to diagnose HAVS on the basis of history, physical examination, and vascular imaging and its treatment options. A 41-year-old man who regularly used vibrating tools presented with nonhealing wounds on his right thumb and third digit. Arteriography revealed occlusions of multiple arteries in his hand with formation of collaterals. We diagnosed HAVS, and his wounds healed after several weeks with appropriate treatment. HAVS is a debilitating condition with often irreversible vascular damage, requiring early diagnosis and treatment.

Effects of acute upper-body vibration on strength and power variables in climbers.

PubMed

Cochrane, Darryl J; Hawke, Emma J

2007-05-01

Whole-body vibration training has recently received a lot of attention with reported enhancements of strength and power qualities in athletes. This study investigated whether upper-body vibration would be able to augment muscular attributes for climbing performance. Twelve healthy active climbers volunteered for the study. All participants underwent 3 treatments--arm cranking (AC), upper-body vibration (UBV), and non-UBV (NUBV)--in a balanced random order, conducted on separate days. Upper-body vibration was generated via a commercialized electric-powered dumbbell with a rotating axis that delivered oscillatory movements to the shoulders and arms. The UBV treatment consisted of performing 5 upper-body exercises for a total duration of 5 minutes. The UBV frequency was set at 26 Hz, amplitude 3 mm. For the NUBV treatment, the participants performed the exact exercises and time constraints as UBV; however, the vibration dumbbell was set at 0 Hz and 0 mm amplitude. The third treatment consisted of AC, which was performed at 75 k.min(-1) for 5 minutes. Pre- and postmuscular performance measures of medicine ball throw, hand grip strength, and a specific climbing maneuver were performed after each treatment. There were no significant treatment differences on medicine ball throw, hand grip strength, and the specific climbing maneuver. Acute UBV exposure did not demonstrate the expected potential neuromuscular enhancements on the climbing performance tests selected for this study.

Vascular hand-arm vibration syndrome--magnetic resonance angiography.

PubMed

Poole, C J M; Cleveland, T J

2016-01-01

The diagnosis of vascular hand-arm vibration syndrome (HAVS) requires consistent symptoms, photographic evidence of digital blanching and sufficient exposure to hand-transmitted vibration (HTV; A(8) > 2.5 m/s2). There is no reliable quantitative investigation for distinguishing HAVS from other causes of Raynaud's phenomenon and from normal individuals. Hypothenar and thenar hammer syndromes produce similar symptoms to HAVS but are difficult to diagnose clinically and may be confused with HAVS. Magnetic resonance angiography (MRA) is a safe and minimally invasive method of visualizing blood vessels. Three cases of vascular HAVS are described in which MRA revealed occlusions of the ulnar, radial and superficial palmar arteries. It is proposed that HTV was the cause of these occlusions, rather than blows to the hand unrelated to vibration, the assumed mechanism for the hammer syndromes. All three cases were advised not to expose their hands to HTV despite one of them being at Stockholm vascular stage 2 (early). MRA should be the investigation of choice for stage 2 vascular HAVS or vascular HAVS with unusual features or for a suspected hammer syndrome. The technique is however technically challenging and best done in specialist centres in collaboration with an occupational physician familiar with the examination of HAVS cases. Staging for HAVS should be developed to include anatomical arterial abnormalities as well as symptoms and signs of blanching. Workers with only one artery supplying a hand, or with only one palmar arch, may be at increased risk of progression and therefore should not be exposed to HTV irrespective of their Stockholm stage. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Vibrotactile perception and effects of short-term exposure to hand-arm vibration.

PubMed

Burström, Lage; Lundström, Ronnie; Hagberg, Mats; Nilsson, Tohr

2009-07-01

This study clarifies whether the established frequency weighting procedure for evaluating exposure to hand-transmitted vibration can effectively evaluate the temporary changes in vibrotactile perception thresholds due to pre-exposure to vibration. In addition, this study investigates the relationship between changes of the vibrotactile perception thresholds and the normalized energy-equivalent frequency-weighted acceleration. The fingers of 10 healthy subjects, five male and five female, were exposed to vibration under 16 conditions with a combination of different frequencies, intensities, and exposure times. The vibration frequencies were 31.5 and 125 Hz and exposure lasted between 2 and 16 min. According to International Organization for Standardization (ISO) 5349-1, the energy-equivalent frequency-weighted acceleration for the experimental time of 16 min is 2.5 or 5.0 m s(-2) root-mean-square, corresponding to a 8-h equivalent acceleration, A(8), of approximately 0.5 and 0.9 m s(-2), respectively. A measure of the vibrotactile perception thresholds was conducted before the different exposures to vibration. Immediately after the vibration exposure, the acute effect was measured continuously on the exposed index finger for the first 75 s, followed by 30 s of measures every minute for a maximum of 10 min. If the subject's thresholds had not recovered, the measures continued for a maximum of 30 min with measurements taken every 5 min. Pre-exposure to vibration significantly influenced vibrotactile thresholds. This study concludes that the influence on the thresholds depends on the frequency of the vibration stimuli. Increased equivalent frequency-weighted acceleration resulted in a significant change in threshold, but the thresholds were unaffected when changes in the vibration magnitude were expressed as the frequency-weighted acceleration or the unweighted acceleration. Moreover, the frequency of the pre-vibration exposure significantly influenced (up to 25 min after exposure) recovery time of the vibrotactile thresholds. This study shows that the frequency weighting procedure in ISO 5349-1 is unable to predict the produced acute changes in the vibrotactile perception. Moreover, the results imply that the calculation of the 'energy-equivalent' frequency-weighted acceleration does not reflect the acute changes of the vibration perception thresholds due to pre-exposure to vibration. Furthermore, when testing for the vibrotactile thresholds, exposure to vibration on the day of a test might influence the results. Until further knowledge is obtained, the previous practice of 3 h avoidance of vibration exposure before assessment is recommended.

Nailfold capillary morphological characteristics of hand-arm vibration syndrome: a cross-sectional study.

PubMed

Chen, QingSong; Chen, GuiPing; Xiao, Bin; Lin, HanSheng; Qu, HongYing; Zhang, DanYing; Shi, MaoGong; Lang, Li; Yang, Bei; Yan, MaoSheng

2016-11-25

The purpose of this study was to investigate the characteristics of nailfold capillaroscopy associated with hand-arm vibration syndrome (HAVS). In total, 113 male gold miners were recruited: 35 workers who were chronically exposed to vibration and developed vibration-induced white finger were defined as the HAVS group, 39 workers who were exposed to vibration but did not have HAVS were classified as the vibration-exposed controls (VEC) group, and 39 workers without vibration exposure were categorised as the non-VEC (NVEC) group. Video capillaroscopy was used to capture images of the 2nd, 3rd and 4th fingers of both hands. The following nailfold capillary characteristics were included: number of capillaries/mm, avascular areas, haemorrhages and enlarged capillaries. The experiments were carried out in the same winter. All characteristics were evaluated under blinded conditions. Significant differences in all morphological characteristics existed between the groups (p<0.05). Avascular areas in the HAVS, VEC and NVEC groups appeared in 74.3%, 43.6% and 25.0% of participants, respectively. A higher percentage of participants had haemorrhages in the HAVS group (65.7%) compared with the other groups (VEC: 7.7% and NVEC: 7.5%). The number of capillaries/mm, input limb width, output limb width, apical width, and ratio of output limb and input limb all had more than 70% sensitivity or specificity of their cut-off value. Nailfold capillary characteristics, especially the number of capillaries/mm, avascular areas, haemorrhages, output limb width, input limb width and apical width alterations, revealed significant associations with HAVS. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

[The health condition of forest workers exposed to noise and vibration produced by chain saws].

PubMed

Malinowska-Borowska, Jolanta; Socholik, Violetta; Harazin, Barbara

2012-01-01

Lumberjacks' working conditions are difficult due to the presence of numerous occupational hazards. Physical factors that pose a health risk are noise and vibration produced by chain saws. Excessive exposure of lumberjacks to noise and vibration can lead to the development of hand-arm vibration syndrome and hearing loss. The aim of the work was to analyze the health condition of forestry workers exposed to occupational physical hazards. A preliminary, questionnaire-based assessment of health status was conducted in 22 chain saw operators. In a group of 15 forestry workers audiometry, vibrotactile perception thresholds and cold provocation test were performed. X-ray diagnostic imaging of upper limbs was also done. At the same time noise and vibration produced by chain saws used in forestry was measured. Vascular or neurological disorders were found in nearly half of tested workers with seniority from 2 to 20 years; 40% of the surveyed was diagnosed with hearing impairment. An 8-hour energy equivalent vibration level measured on chain saws was 4.6 m/s2. An 8-hour equivalent sound pressure level was 99.1 dB(A). The threshold limit values for noise and vibration are exceeded at woodcutters' posts. There are changes in lumberjacks' health resulting from exposure to harmful physical agents. Preventive actions are urgently needed to be addressed, especially to people employed in single-handed forestry companies.

Hand function in workers with hand-arm vibration syndrome.

PubMed

Cederlund, R; Isacsson, A; Lundborg, G

1999-01-01

Hand-arm vibration syndrome has been specially addressed in the Scandinavian countries in recent years, but the syndrome is still not sufficiently recognized in many countries. The object of this preliminary study was to describe the nature and character of vibration-induced impairment in the hands of exposed workers. Twenty symptomatic male workers (aged 28 to 65 years) subjected to vibration by hand-held tools were interviewed about subjective symptoms and activities of daily living and were assessed with a battery of objective tests for sensibility, dexterity, grip function, and grip strength. The test results were compared with normative data. The majority of patients complained of cold intolerance, numbness, pain, sensory impairment, and difficulties in handling manual tools and in handwriting. The various objective tests showed considerable variation in indications of pathologic outcome, revealing differences in sensitivity to detect impaired hand function. Semmes-Weinstein monofilament testing for perception of light touch-deep pressure sensation, the small-object shape identification test, and moving two-point discrimination testing for functional sensibility provided the most indications of pathologic outcomes. The authors conclude that vibration-exposed patients present considerable impairment in hand function.

Work disability after diagnosis of hand-arm vibration syndrome.

PubMed

Sauni, Riitta; Toivio, Pauliina; Pääkkönen, Rauno; Malmström, Jari; Uitti, Jukka

2015-11-01

Our aim was to study the course of vasospastic and sensorineural symptoms after the clinical diagnosis of hand-arm vibration syndrome (HAVS), and the association of current HAVS symptoms with occupational status, self-evaluation of health, quality of life, and work ability. We gathered all HAVS cases diagnosed at the Finnish Institute of Occupational Health in Helsinki and Tampere during 1990-2008. A questionnaire was sent to all these patients (n = 241). Altogether 149 of them (62 %) returned the questionnaire. Cumulative lifelong vibration exposure was evaluated on the basis of the data in the patient files. On average, 8.5 years after the diagnosis of HAVS, approximately one-third of the patients reported improvement in symptoms of vibration-induced white finger (VWF) and the sensorineural symptoms. Young age and shorter exposure time were associated with improvement in VWF symptoms (p = 0.033 and p < 0.001, respectively). Persistent or deteriorated symptoms of both VWF and sensorineural symptoms were associated with lowered work ability, quality of life (EQ-5D), and general health, also after adjusting for age, smoking, and diseases other than HAVS. The patients' own prediction of work ability in 2 years was more negative if the VWF symptoms or sensorineural symptoms had continued after diagnosis of HAVS (p = 0.065 and p = 0.001, respectively). Our results suggest that in about two-thirds of the patients, the HAVS symptoms may stabilize or deteriorate in the follow-up. Considering the effects on work ability, timely prevention measures should be taken more actively to help patients continue their working careers.

Review and Evaluation of Hand-Arm Coordinate Systems for Measuring Vibration Exposure, Biodynamic Responses, and Hand Forces.

PubMed

Dong, Ren G; Sinsel, Erik W; Welcome, Daniel E; Warren, Christopher; Xu, Xueyan S; McDowell, Thomas W; Wu, John Z

2015-09-01

The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study.

Mechanical impedance and absorbed power of hand-arm under x(h)-axis vibration and role of hand forces and posture.

PubMed

Aldien, Yasser; Marcotte, Pierre; Rakheja, Subhash; Boileau, Paul-Emile

2005-07-01

The biodynamic responses of the hand-arm system under x(h)-axis vibration are investigated in terms of the driving point mechanical impedance (DPMI) and absorbed power in a laboratory study. For this purpose, seven healthy male subjects are exposed to two levels of random vibration in the 8-1,000 Hz frequency range, using three instrumented cylindrical handles of different diameters (30, 40 and 50 mm), and different combinations of grip (10, 30 and 50 N) and push (0, 25 and 50 N) forces. The experiments involve grasping the handle while adopting two different postures, involving elbow flexion of 90 degrees and 180 degrees, with wrist in the neutral position for both postures. The analyses of the results revealed peak DPMI magnitude and absorbed power responses near 25 Hz and 150 Hz, for majority of the test conditions considered. The frequency corresponding to the peak response increased with increasing hand forces. Unlike the absorbed power, the DPMI response was mostly observed to be insensitive to variations in the excitation magnitude. The handle diameter revealed obvious effects on the DPMI magnitude, specifically at frequencies above 250 Hz, which was not evident in the absorbed power due to relatively low velocity at higher frequencies. The influence of hand forces was also evident on the DPMI magnitude response particularly at frequencies. above 100 Hz, while the effect of hand-arm posture on the DPMI magnitude was nearly negligible. The magnitude of power absorbed within the hand and arm was observed to be strongly dependent upon the excitation level over the entire frequency range, while the influence of hand-arm posture on the total absorbed power was observed to be important. The effect of variations in the hand forces on the absorbed power was relatively small for the bent elbow posture, while an increase in either the grip or the push force coupled with the extended arm posture resulted in considerably higher energy absorption. The results suggested that the handle size, hand-arm posture and hand forces, produce coupled effect on the biodynamic response of the hand-arm system.

Review and Evaluation of Hand–Arm Coordinate Systems for Measuring Vibration Exposure, Biodynamic Responses, and Hand Forces

PubMed Central

Dong, Ren G.; Sinsel, Erik W.; Welcome, Daniel E.; Warren, Christopher; Xu, Xueyan S.; McDowell, Thomas W.; Wu, John Z.

2015-01-01

The hand coordinate systems for measuring vibration exposures and biodynamic responses have been standardized, but they are not actually used in many studies. This contradicts the purpose of the standardization. The objectives of this study were to identify the major sources of this problem, and to help define or identify better coordinate systems for the standardization. This study systematically reviewed the principles and definition methods, and evaluated typical hand coordinate systems. This study confirms that, as accelerometers remain the major technology for vibration measurement, it is reasonable to standardize two types of coordinate systems: a tool-based basicentric (BC) system and an anatomically based biodynamic (BD) system. However, these coordinate systems are not well defined in the current standard. Definition of the standard BC system is confusing, and it can be interpreted differently; as a result, it has been inconsistently applied in various standards and studies. The standard hand BD system is defined using the orientation of the third metacarpal bone. It is neither convenient nor defined based on important biological or biodynamic features. This explains why it is rarely used in practice. To resolve these inconsistencies and deficiencies, we proposed a revised method for defining the realistic handle BC system and an alternative method for defining the hand BD system. A fingertip-based BD system for measuring the principal grip force is also proposed based on an important feature of the grip force confirmed in this study. PMID:26929824

Current Perception Threshold for Assessment of the Neurological Components of Hand-Arm Vibration Syndrome: A Review

PubMed Central

Kurozawa, Youichi; Hosoda, Takenobu; Nasu, Yoshiro

2010-01-01

Current perception threshold (CPT) has been proposed as a quantitative method for assessment of peripheral sensory nerve function. The aim of this review of selected reports is to provide an overview of CPT measurement for the assessment of the neurological component of hand-arm vibration syndrome (HAVS). The CPT values at 2000 Hz significantly increased for patients with HAVS. This result supports the previous histological findings that demyelination is found predominantly in the peripheral nerves in the hands of men exposed to hand-arm vibration. Diagnostic sensitivity and specificity were high for severe cases of Stockholm sensorineural (SSN) stage 3 compared with non-exposed controls, but not high for mild cases of SSN stage 1 or 2 and for carpal tunnel syndrome associated with HAVS. However, there are only a few studies on the diagnostic validity of the CPT test for the neurological components of HAVS. Further research is needed and should include diagnostic validity and standardizing of measurement conditions such as skin temperature. PMID:24031119

Subjective scaling of hand-arm vibration.

PubMed

Maeda, Setsuo; Shibata, Nobuyuki

2008-04-01

The purpose of this research was to establish a scale for comfort with regard to hand-arm vibration using the category judgment method and to validate the frequency-weighting method of the ISO 5349-1 standard. Experiments were conducted using random signals as stimuli. These stimuli consisted of three types of signal, namely designated stimulus F, with flat power spectrum density (PSD) ranging from 1 to 1,000 Hz, stimulus H with PSD which became 20 dB higher at 1,000 Hz than at 1 Hz, and stimulus L that had a PSD 20 dB lower at 1,000 Hz. These stimuli were selected from the specific spectrum patterns of hand-held vibration tools. These signals were modified by the Wh frequency weighting in accordance with ISO 5349-1, and the R.M.S. values were adjusted to be equal. In addition, the signal levels were varied over a range of five steps to create 15 kinds of individual stimuli. The subjects sat in front of a vibrator and grasped the mounted handle which exposed them to vertical vibrations after which they were asked to choose a numerical category to best indicate their perceived level of comfort (or otherwise) during each stimulus. From the experimental results of the category judgment method, the relationship between the psychological values and the frequency-weighted R.M.S. acceleration according to the ISO 5349-1 standard was obtained. It was found that the subjective response scaling of hand-arm vibration can be used for design-objective values of hand-held tool vibration.

Occupational hand-arm vibration syndrome in Korea.

PubMed

Yoo, Cheolin; Lee, Ji-Ho; Lee, Choong-Ryeol; Kim, Yangho; Lee, Hun; Choi, Younghee; Kim, Young Wook; Chae, Chang Ho; Kim, Hyokyoung; Koh, Sang Baek; Kim, Euna; Lee, Lu Jin; Lee, Kiyoung

2005-06-01

It is suspected that there is a large number of patients suffering from hand-arm vibration syndrome (HAVS) in Korea. However, no cases have been reported since 1992. This study was conducted to identify HAVS cases and determine the characteristics of the syndrome. In April 2001, the Busan, Ulsan, and Gyeong-Nam Province Occupational Disease Surveillance System (BUGODSS) was established to identify work-related HAVS and other occupational diseases. In the 2 years of this project, occupational physicians from five hospitals in these provinces collected information by way of interviews and questionnaires during mandatory occupational medical examinations. Among the initial 189 suspected HAVS cases, 58 volunteers were given cold-water provocation tests in order to diagnose the vascular component of the disorder. One hundred fifty-four approximately occupational HAVS cases were identified from ca. 21,000 workers. One hundred fifty about of these cases were male. The cases were most often found in workers from the shipbuilding industry, and the grinder was the most common source of vibration exposure. Cases of sensorineural disorder (SD) were more common than cases of vascular disorder (VD). The mean values of the finger skin temperature and its recovery rate at 5 min and 10 min after cold-water provocation were significantly lower in the group with the VD than in the group with the SD. We identified 154 occupational HAVS cases, although no cases have been reported during the occupational medical examinations mandated by the state. The majority of the cases were in workers that used grinders in the shipbuilding industry. We determined that peripheral VD and peripheral SD can progress independently of each other. We conclude that exposure to hand-transmitted vibration (HTV) and HAVS cases are common in shipbuilding industry in Korea. The recovery rate of finger skin temperature after cold-water provocation is one of the useful methods for diagnosing the vascular component of HAVS.

Improving hand sensibility in vibration induced neuropathy: A case-series.

PubMed

Rosén, Birgitta; Björkman, Anders; Lundborg, Göran

2011-04-27

We report a long-term series of nine workers suffering from vibration-induced neuropathy, after many years of exposure to hand-held vibrating tools at high or low frequency. They were treated with temporary selective cutaneous anaesthesia (EMLA® cream) of the forearm repeatedly for a period up to one year (in two cases four years). The aim was to improve their capacity to perceive touch and thereby improve hand function and diminish disability. The treatment principle is based on current concepts of brain plasticity, where a deafferentation of a skin area results in improved sensory function in adjacent skin areas. All participants had sensory hand problems in terms of numbness (median touch thresholds > 70 mg) and impaired hand function influencing ADL (mean DASH score 22).After an initial identical self-administered treatment period of 8 weeks (12-15 treatments with increasing intervals) they did one treatment every 2-3 month. After one year sensibility (touch thresholds and tactile discrimination) as well as hand function (mean DASH score 13) were improved in a majority of the cases. Seven of the participants choose to continue the treatment after the first year and two of them have continued at a regular basis for up to four years. A surprising, secondary finding was diminishing nocturnal numbness of the hand and arm in eight of the nine subjects from "frequently" to "hardly ever or never". Our observations open new perspectives for treatment of impaired sensibility and hand function in a group of patients with vibration induced hand problems where we have no treatment to offer today.

Improving hand sensibility in vibration induced neuropathy: A case-series

PubMed Central

2011-01-01

Objectives We report a long-term series of nine workers suffering from vibration-induced neuropathy, after many years of exposure to hand-held vibrating tools at high or low frequency. They were treated with temporary selective cutaneous anaesthesia (EMLA® cream) of the forearm repeatedly for a period up to one year (in two cases four years). The aim was to improve their capacity to perceive touch and thereby improve hand function and diminish disability. The treatment principle is based on current concepts of brain plasticity, where a deafferentation of a skin area results in improved sensory function in adjacent skin areas. Methods All participants had sensory hand problems in terms of numbness (median touch thresholds > 70 mg) and impaired hand function influencing ADL (mean DASH score 22). After an initial identical self-administered treatment period of 8 weeks (12-15 treatments with increasing intervals) they did one treatment every 2-3 month. Results After one year sensibility (touch thresholds and tactile discrimination) as well as hand function (mean DASH score 13) were improved in a majority of the cases. Seven of the participants choose to continue the treatment after the first year and two of them have continued at a regular basis for up to four years. A surprising, secondary finding was diminishing nocturnal numbness of the hand and arm in eight of the nine subjects from "frequently" to "hardly ever or never". Conclusions Our observations open new perspectives for treatment of impaired sensibility and hand function in a group of patients with vibration induced hand problems where we have no treatment to offer today. PMID:21524297

Effects of wrist tendon vibration on targeted upper-arm movements in poststroke hemiparesis.

PubMed

Conrad, Megan O; Scheidt, Robert A; Schmit, Brian D

2011-01-01

Impaired motor control of the upper extremity after stroke may be related to lost sensory, motor, and integrative functions of the brain. Artificial activation of sensory afferents might improve control of movement by adding excitatory drive to sensorimotor control structures. The authors evaluated the effect of wrist tendon vibration (TV) on paretic upper-arm stability during point-to-point planar movements. TV (70 Hz) was applied to the forearm wrist musculature of 10 hemiparetic stroke patients as they made center-out planar arm movements. End-point stability, muscle activity, and grip pressure were compared as patients stabilized at the target position for trials completed before, during, and after the application of the vibratory stimulus. Prior to vibration, hand position fluctuated as participants attempted to maintain the hand at the target after movement termination. TV improved arm stability, as evidenced by decreased magnitude of hand tangential velocity at the target. Improved stability was accompanied by a decrease in muscle activity throughout the arm as well as a mean decrease in grip pressure. These results suggest that vibratory stimulation of the distal wrist musculature enhances stability of the proximal arm and can be studied further as a mode for improving end-point stability during reaching in hemiparetic patients.

The effect of vibration exposure during haul truck operation on grip strength, touch sensation, and balance

PubMed Central

Pollard, Jonisha; Porter, William; Mayton, Alan; Xu, Xueyan; Weston, Eric

2017-01-01

Falls from mobile equipment are reported at surface mine quarry operations each year in considerable numbers. Research shows that a preponderance of falls occur while getting on/off mobile equipment. Contributing factors to the risk of falls include the usage of ladders, exiting onto a slippery surface, and foot or hand slippage. Balance issues may also contribute to fall risks for mobile equipment operators who are exposed to whole-body vibration (WBV). For this reason, the National Institute for Occupational Safety and Health, Office of Mine Safety and Health Research conducted a study at four participating mine sites with seven haul truck operators. The purpose was to ascertain whether WBV and hand-arm vibration (HAV) exposures for quarry haul truck operators were linked to short-term decreases in performance in relation to postural stability, touch sensation threshold, and grip strength that are of crucial importance when getting on/off the trucks. WBV measures of frequency-weighted RMS accelerations (wRMS) and vibration dose value (VDV), when compared to the ISO/ANSI standards, were mostly below levels identified for the Health Guidance Caution Zone (HGCZ), although there were instances where the levels were within and above the specified Exposure Action Value. Comparably, all mean HAV levels, when compared to the ISO/ANSI standards, were below the HGCZ. For the existing conditions and equipment, no significant correlation could be identified between the WBV, HAV, postural stability, touch sensation threshold, and grip strength measures taken during this study. PMID:28220051

Interaction between vibration-evoked proprioceptive illusions and mirror-evoked visual illusions in an arm-matching task.

PubMed

Tsuge, Mikio; Izumizaki, Masahiko; Kigawa, Kazuyoshi; Atsumi, Takashi; Homma, Ikuo

2012-12-01

We studied the influence of false proprioceptive information generated by arm vibration and false visual information provided by a mirror in which subjects saw a reflection of another arm on perception of arm position, in a forearm position-matching task in right-handed subjects (n = 17). The mirror was placed between left and right arms, and arranged so that the reflected left arm appeared to the subjects to be their unseen right (reference) arm. The felt position of the right arm, indicated with a paddle, was influenced by vision of the mirror image of the left arm. If the left arm appeared flexed in the mirror, subjects felt their right arm to be more flexed than it was. Conversely, if the left arm was extended, they felt their right arm to be more extended than it was. When reference elbow flexors were vibrated at 70-80 Hz, an illusion of extension of the vibrated arm was elicited. The illusion of a more flexed reference arm evoked by seeing a mirror image of the flexed left arm was reduced by vibration. However, the illusion of extension of the right arm evoked by seeing a mirror image of the extended left arm was increased by vibration. That is, when the mirror and vibration illusions were in the same direction, they reinforced each other. However, when they were in opposite directions, they tended to cancel one another. The present study shows the interaction between proprioceptive and visual information in perception of arm position.

Haemodynamic changes in ipsilateral and contralateral fingers caused by acute exposures to hand transmitted vibration.

PubMed Central

Bovenzi, M; Griffin, M J

1997-01-01

OBJECTIVES: To investigate changes in digital circulation during and after exposure to hand transmitted vibration. By studying two frequencies and two magnitudes of vibration, to investigate the extent to which haemodynamic changes depend on the vibration frequency, the vibration acceleration, and the vibration velocity. METHODS: Finger skin temperature (FST), finger blood flow (FBF), and finger systolic pressure were measured in the fingers of both hands in eight healthy men. Indices of digital vasomotor tone-such as critical closing pressure and vascular resistance-were estimated by pressure-flow curves obtained with different hand heights. With a static load of 10 N, the right hand was exposed for 30 minutes to each of the following root mean squared (rms) acceleration magnitudes and frequencies of vertical vibration: 22 m.s-2 at 31.5 Hz, 22 m.s-2 at 125 Hz, and 87 m.s-2 at 125 Hz. A control condition consisted of exposure to the static load only. The measures of digital circulation and vasomotor tone were taken before exposure to the vibration and the static load, and at 0, 20, 40, and 60 minutes after the end of each exposure. RESULTS: Exposure to static load caused no significant changes in FST, FBF, or indices of vasomotor tone in either the vibrated right middle finger or the non-vibrated left middle finger. In both fingers, exposure to vibration of 125 Hz and 22 m.s-2 produced a greater reduction in FBF and a greater increase in vasomotor tone than did vibration of 31.5 Hz and 22 m.s-2. In the vibrated right finger, exposure to vibration of 125 Hz and 87 m.s-2 provoked an immediate vasodilation which was followed by vasoconstriction during recovery. The non-vibrated left finger showed a significant increase in vasomotor tone throughout the 60 minute period after the end of vibration exposure. CONCLUSIONS: The digital circulatory response to acute vibration depends upon the magnitude and frequency of the vibration stimulus. Vasomotor mechanisms, mediated both centrally and locally, are involved in the reaction of digital vessels to acute vibration. The pattern of the haemodynamic changes in the fingers exposed to the vibration frequencies used in this study do not seem to support the frequency weighting assumed in the current international standard ISO 5349. PMID:9326160

Reduction in finger blood flow induced by hand-transmitted vibration: effect of hand elevation.

PubMed

Ye, Ying; Mauro, Marcella; Bovenzi, Massimo; Griffin, Michael J

2015-10-01

This study investigated the effect of hand elevation on reductions in finger blood flow (FBF) induced by hand-transmitted vibration. Fourteen males attended six sessions on six separate days, with a control sessions and a vibration session (125-Hz vibration at 44 ms(-2) rms) with the right hand supported at each of three elevations: 20 cm below heart level (HL), at HL, and 20 cm above HL. Finger blood flow on the left and right hand was measured every 30 s during each 25-min session comprised of five periods: (1) no force and no vibration (5 min), (2) 2-N force and no vibration (5 min), (3) 2-N force and vibration (5 min), (4) 2-N force and no vibration (5 min), and (5) no force and no vibration (5 min). Without vibration, FBF decreased with increasing elevation of the hand. During vibration of the right hand, FBF reduced on both hands. With elevation of the right hand, the percentage reduction in FBF due to vibration (relative to FBF on the same finger at the same elevation before exposure to vibration) was similar on the middle and little fingers of both hands. After cessation of vibration, there was delayed return of FBF with all three hand heights. Vibration of one hand reduces FBF on both exposed and unexposed hands, with the reduction dependent on the elevation of the hand. The mechanisms responsible for vibration-induced reductions in FBF seem to reduce blood flow as a percentage of the blood flow without vibration. Tasks requiring the elevation of the hands will be associated with lower FBF, and the FBF will be reduced further if there is exposure to hand-transmitted vibration.

[Management of the worker affected by shoulder pathology].

PubMed

Rotini, Roberto; Bonfiglioli, Roberta

2014-01-01

Shoulder disorders due to overexertion include joint and soft tissues chronic conditions and are an important cause of disability. Shoulder pain is one of the most common musculoskeletal disorders and has been associated to manual handling of heavy loads, high repetition jobs, exposure to hand-arm vibration and to overhead activities. Diagnosis of shoulder disorders is primarily based on clinical examination; selected cases should be referred to an orthopedic specialist and to imaging. Return to normal activities should be encouraged.

Uptake and quality of health surveillance for noise and hand-arm vibration.

PubMed

Poole, K; Mason, H J; Harris-Roberts, J

2011-08-01

Health surveillance (HS) is required for employees if noise or hand-arm vibration (HAV) exposures are likely to be above exposure action levels. The extent to which employers comply with Health and Safety Executive (HSE) regulations is unclear. To establish the uptake and quality of HS for noise and HAV in high-risk industries. A cross-sectional telephone-based questionnaire study involving employers in high-risk industries for noise or HAV. A total of 246 and 386 interviews were completed for noise and HAV, respectively. The uptake of HS in the cohorts was 17 and 10%, respectively. Selection of those companies thought to have 'higher risk' increased the uptake to 25 and 18%, respectively. The proportion of companies carrying out HS was strongly related to the size of the company, with smaller companies less likely to provide this for their employees. A large proportion of companies that reported having HS in place had formal procedures for managing exposed workers (90 and 83% for noise and HAV, respectively), received feedback on individual workers (81 and 80%) and some reported that they used this information to inform their risk management process (58 and 63%). The frequency of HS for HAV was in line with that suggested in HSE guidance in 70% of cases, however, for noise, it was often utilized more frequently. While many of the companies appear to be following HSE guidance, there is a significant number that are not. Further initiatives that engage with smaller companies may help increase HS provision.

An interpretative phenomenological analysis of the psychological ramifications of hand-arm vibration syndrome.

PubMed

Ayers, Beverley; Forshaw, Mark

2010-05-01

With a substantial number of individuals diagnosed with Hand-Arm Vibration Syndrome (HAVS) and the preponderance of research focused on the medical and paramedical issues, the psychological and mental health sequelae of HAVS are largely neglected within the published literature. A series of focus groups and interviews were conducted involving nine people who had been diagnosed with HAVS. Transcripts of these interviews were analysed using Interpretative Phenomenological Analysis. Four key themes were identified within the discourse of individuals affected by HAVS: machismo; coping; psychological impacts; and the development of support services for HAVS. Clinical implications are briefly discussed.

Hand and body radiation exposure with the use of mini C-arm fluoroscopy.

PubMed

Tuohy, Christopher J; Weikert, Douglas R; Watson, Jeffry T; Lee, Donald H

2011-04-01

To determine whole body and hand radiation exposure to the hand surgeon wearing a lead apron during routine intraoperative use of the mini C-arm fluoroscope. Four surgeons (3 hand attending surgeons and 1 hand fellow) monitored their radiation exposure for a total of 200 consecutive cases (50 cases per surgeon) requiring mini C-arm fluoroscopy. Each surgeon measured radiation exposure with a badge dosimeter placed on the outside breast pocket of the lead apron (external whole body exposure), a second badge dosimeter under the lead apron (shielded whole body exposure), and a ring dosimeter (hand exposure). Completed records were noted in 198 cases, with an average fluoroscopy time of 133.52 seconds and average cumulative dose of 19,260 rem-cm(2) per case. The total measured radiation exposures for the (1) external whole body exposure dosimeters were 16 mrem (for shallow depth), 7 mrem (for eye depth), and less than 1 mrem (for deep depth); (2) shielded whole body badge dosimeters recorded less than 1 mrem; and (3) ring dosimeters totaled 170 mrem. The total radial exposure for 4 ring dosimeters that had registered a threshold of 30 mrem or more of radiation exposure was 170 mrem at the skin level, for an average of 42.5 mrem per dosimeter ring or 6.3 mrem per case. This study of whole body and hand radiation exposure from the mini C-arm includes the largest number of surgical cases in the published literature. The measured whole body and hand radiation exposure received by the hand surgeon from the mini C-arm represents a minimal risk of radiation, based on the current National Council on Radiation Protection and Management standards of annual dose limits (5,000 mrem per year for whole body and 50,000 mrem per year to the extremities). Copyright © 2011 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

[Clinical efficacy of mouse nerve growth factor in treatment of occupational hand-arm vibration disease].

PubMed

Fan, Chunyue; Wang, Yanyan; Zhang, Ying; Lang, Li; Deng, Xiaofeng; Cheng, Ying

2014-12-01

To investigate the efficacy of mouse nerve growth factor (mNGF) in treating occupational hand-arm vibration disease (HAVD). Sixty-four patients with HAVD were equally and randomly divided into treatment group and control group. The control group was given Salvia miltiorrhiza Bunge and deproteinized extract of calf blood to improve circulation, and also given methylcobalamin tablets and vitamin B6 for neurotrophic treatment. In addition to the above treatments for the control group, the treatment group was also given 30 µg/d mNGF by intramuscular injection for two courses (4 weeks for each course) with a 15-day interval. Both the treatment group and the control group showed significant improvements in clinical symptoms and signs (hand numbness and pain, and reduced senses of touch, pain, and vibration), cold water loading test (CWLT), and electroneuromyography (ENMG) after treatments (P < 0.05). And the treatment group had significantly more improvements than the control group (P < 0.05). mNGF can significantly improve hand numbness and pain, reduced senses of touch, pain, and vibration, CWLT, and ENMG, so it has better clinical effect and safety in treating HAVD. Early diagnosis and treatment can improve the outcome of patients with HAVD.

Hand-arm vibration and the risk of vascular and neurological diseases—A systematic review and meta-analysis

PubMed Central

Wahlström, Jens; Burström, Lage

2017-01-01

Background Increased occurrence of Raynaud’s phenomenon, neurosensory injury and carpal tunnel syndrome has been reported for more than 100 years in association with work with vibrating machines. The current risk prediction modelling (ISO-5349) for “Raynaud’s phenomenon” is based on a few studies published 70 to 40 years ago. There are no corresponding risk prediction models for neurosensory injury or carpal tunnel syndrome, nor any systematic reviews comprising a statistical synthesis (meta-analysis) of the evidence. Objectives Our aim was to provide a systematic review of the literature on the association between Raynaud’s phenomenon, neurosensory injuries and carpal tunnel syndrome and hand-arm vibration (HAV) exposure. Moreover the aim was to estimate the magnitude of such an association using meta-analysis. Methods This systematic review covers the scientific literature up to January 2016. The databases used for the literature search were PubMed and Science Direct. We found a total of 4,335 abstracts, which were read and whose validity was assessed according to pre-established criteria. 294 articles were examined in their entirety to determine whether each article met the inclusion criteria. The possible risk of bias was assessed for each article. 52 articles finally met the pre-established criteria for inclusion in the systematic review. Results The results show that workers who are exposed to HAV have an increased risk of vascular and neurological diseases compared to non-vibration exposed groups. The crude estimate of the risk increase is approximately 4–5 fold. The estimated effect size (odds ratio) is 6.9 for the studies of Raynaud’s phenomenon when including only the studies judged to have a low risk of bias. The corresponding risk of neurosensory injury is 7.4 and the equivalent of carpal tunnel syndrome is 2.9. Conclusion At equal exposures, neurosensory injury occurs with a 3-time factor shorter latency than Raynaud’s phenomenon. Which is why preventive measures should address this vibration health hazard with greater attention. PMID:28704466

Assessment of thermotactile and vibrotactile thresholds for detecting sensorineural components of the hand-arm vibration syndrome (HAVS).

PubMed

Ye, Ying; Griffin, Michael J

2018-01-01

Thermotactile thresholds and vibrotactile thresholds are measured to assist the diagnosis of the sensorineural component of the hand-arm vibration syndrome (HAVS). This study investigates whether thermotactile and vibrotactile thresholds distinguish between fingers with and without numbness and tingling. In 60 males reporting symptoms of the hand-arm vibration syndrome, thermotactile thresholds for detecting hot and cold temperatures and vibrotactile thresholds at 31.5 and 125 Hz were measured on the index and little fingers of both hands. In fingers reported to suffer numbness or tingling, hot thresholds increased, cold thresholds decreased, and vibrotactile thresholds at both 31.5 and 125 Hz increased. With sensorineural symptoms on all three phalanges (i.e. numbness or tingling scores of 6), both thermotactile thresholds and both vibrotactile thresholds had sensitivities greater than 80% and specificities around 90%, with areas under the receiver operating characteristic curves around 0.9. There were correlations between all four thresholds, but cold thresholds had greater sensitivity and greater specificity on fingers with numbness or tingling on only the distal phalanx (i.e. numbness or tingling scores of 1) suggesting cold thresholds provide better indications of early sensorineural disorder. Thermotactile thresholds and vibrotactile thresholds can provide useful indications of sensorineural function in patients reporting symptoms of the sensorineural component of HAVS.

Effects of wrist tendon vibration on arm tracking in people poststroke.

PubMed

Conrad, Megan O; Scheidt, Robert A; Schmit, Brian D

2011-09-01

The goal of this study was to evaluate the influence of wrist tendon vibration on a multijoint elbow/shoulder tracking task. We hypothesized that tendon vibration applied at the wrist musculature would improve upper arm tracking performance in chronic stroke survivors through increased, Ia-afferent feedback to the central nervous system (CNS). To test this hypothesis, 10 chronic stroke and 5 neurologically intact subjects grasped the handle of a planar robot as they tracked a target through a horizontal figure-8 pattern. A total of 36 trials were completed by each subject. During the middle trials, 70-Hz tendon vibration was applied at the wrist flexor tendons. Position, velocity, and electromyography data were evaluated to compare the quality of arm movements before, during, and after trials with concurrent vibration. Despite tracking a target that moved at a constant velocity, hand trajectories appeared to be segmented, displaying alternating intervals of acceleration and deceleration. Segments were identifiable in tangential velocity data as single-peaked, bell-shaped speed pulses. When tendon vibration was applied at the wrist musculature, stroke subjects experienced improved tracking performance in that hand path lengths and peak speed variability decreased, whereas movement smoothness increased. These performance improvements were accompanied by decreases in the muscle activity during movement. Possible mechanisms behind improved movement control in response to tendon vibration may include improved sensorimotor integration or improved cortical modulation of spinal reflex activity.

Effects of wrist tendon vibration on arm tracking in people poststroke

PubMed Central

Conrad, Megan O.; Scheidt, Robert A.

2011-01-01

The goal of this study was to evaluate the influence of wrist tendon vibration on a multijoint elbow/shoulder tracking task. We hypothesized that tendon vibration applied at the wrist musculature would improve upper arm tracking performance in chronic stroke survivors through increased, Ia-afferent feedback to the central nervous system (CNS). To test this hypothesis, 10 chronic stroke and 5 neurologically intact subjects grasped the handle of a planar robot as they tracked a target through a horizontal figure-8 pattern. A total of 36 trials were completed by each subject. During the middle trials, 70-Hz tendon vibration was applied at the wrist flexor tendons. Position, velocity, and electromyography data were evaluated to compare the quality of arm movements before, during, and after trials with concurrent vibration. Despite tracking a target that moved at a constant velocity, hand trajectories appeared to be segmented, displaying alternating intervals of acceleration and deceleration. Segments were identifiable in tangential velocity data as single-peaked, bell-shaped speed pulses. When tendon vibration was applied at the wrist musculature, stroke subjects experienced improved tracking performance in that hand path lengths and peak speed variability decreased, whereas movement smoothness increased. These performance improvements were accompanied by decreases in the muscle activity during movement. Possible mechanisms behind improved movement control in response to tendon vibration may include improved sensorimotor integration or improved cortical modulation of spinal reflex activity. PMID:21697444

Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows.

PubMed

Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid; Svendsen, Susanne Wulff

2018-03-01

We aimed to identify intensities of occupational mechanical exposures (force, arm elevation and repetition) that do not entail an increased risk of surgery for subacromial impingement syndrome (SIS) even after prolonged durations of exposure. Additionally, we wanted to evaluate if exposure to hand-arm vibration (HAV) is an independent risk factor. We used data from a register-based cohort study of the entire Danish working population (n=2 374 403). During follow-up (2003-2008), 14 118 first-time events of surgery for SIS occurred. For each person, we linked register-based occupational codes (1993-2007) to a general population job exposure matrix to obtain year-by-year exposure intensities on measurement scales for force, upper arm elevation >90° and repetition and expert rated intensities of exposure to HAV. For 10-year exposure time windows, we calculated the duration of exposure at specific intensities above minimal (low, medium and high). We used a logistic regression technique equivalent to discrete survival analysis adjusting for cumulative effects of other mechanical exposures. We found indications of safe exposure intensities for repetition (median angular velocity <45°/s), while force exertion ≥10% of maximal voluntary electrical activity and upper arm elevation >90° >2 min/day implied an increased risk reaching ORs of 1.7 and 1.5 after 10 years at low intensities. No associations were found for HAV. We found indications of safe exposure intensities for repetition. Any intensities of force and upper arm elevation >90° above minimal implied an increased risk across 10-year exposure time windows. No independent associations were found for HAV. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Biodynamic response at the palm of the human hand subjected to a random vibration.

PubMed

Dong, Ren G; McDowell, Thomas W; Welcome, Daniel E

2005-01-01

This study investigated the biodynamic response (BR) distributed at the palm of the hand subjected to a random vibration. Twelve male subjects were used in the experiment. Each subject applied three coupling actions (grip-only, push-only, and combined grip and push) on a simulated tool handle at three different levels (50, 75, and 100 N) of palm force. This study found that the hand-arm system resonated mostly in the frequency range of 20 to 50 Hz, depending on the specific test treatment and individual characteristics. The maximum vibration power transmission through the palm occurred at the resonant frequency. Increasing the effective palm force generally increased the BR magnitude and resonant frequency. The apparent stiffness measured at the middle frequencies (80-100 Hz) is correlated to the BR in almost the entire frequency range (20-1,000 Hz). Under the same palm force, the push-only action corresponded to the highest BR values while the grip-only action generally produced the lowest values. Since the resonant frequency range matches the dominant vibration frequency range of many percussive tools, it is anticipated that the palm BR and vibration power transmission may have an association with vibration-induced injuries or disorders in the wrist-arm system among the workers using these tools.

Reductions in finger blood flow induced by 125-Hz vibration: effect of location of contact with vibration.

PubMed

Ye, Ying; Griffin, Michael J

2016-04-01

This study investigated whether the reductions in finger blood flow induced by 125-Hz vibration applied to different locations on the hand depend on thresholds for perceiving vibration at these locations. Subjects attended three sessions during which vibration was applied to the right index finger, the right thenar eminence, or the left thenar eminence. Absolute thresholds for perceiving vibration at these locations were determined. Finger blood flow in the middle finger of both hands was then measured at 30-s intervals during five successive 5-min periods: (i) pre-exposure, (ii) pre-exposure with 2-N force, (iii) 2-N force with vibration, (iv) post-exposure with 2-N force, (v) recovery. During period (iii), vibration was applied at 15 dB above the absolute threshold for perceiving vibration at the right thenar eminence. Vibration at all three locations reduced finger blood flow on the exposed and unexposed hand, with greater reductions when vibrating the finger. Vibration-induced vasoconstriction was greatest for individuals with low thresholds and locations of excitation with low thresholds. Differences in vasoconstriction between subjects and between locations are consistent with the Pacinian channel mediating both absolute thresholds and vibration-induced vasoconstriction.

Normative data for neuromuscular assessment of the hand-arm vibration syndrome and its retrospective applications in Korean male workers.

PubMed

Ahn, Ryeok; Yoo, Cheol-In; Lee, Hun; Sim, Chang-Sun; Sung, Joo Hyun; Yoon, Jae-Kook; Shin, Song-Woo

2013-10-01

The purpose of this study was to describe normative data for the neuromuscular assessments of the hand-arm vibration syndrome (HAVS) in Korean. Data for the vibrotactile perception threshold (VPT) at three frequencies (31.5, 125, and 250 Hz), the hand grip strength (HGS), the finger pinch strength (FPS), the finger tapping test, and the Purdue pegboard tests were collected from 120 male office workers aged 30-59 years with no prior history of regular use of handheld vibrating tools. The collected data were compared with the results of a similar study of shipbuilding workers in order to investigate the diagnostic utility of clinical test for HAVS. The mean VPT values indicate that no significant differences were observed between the dominant and non-dominant hands or between the index and little fingers. The age group of 30s was highly sensitive to vibration input with a peak in sensitivity at 125 Hz among all age groups. In neuromuscular performance, dominant hands are usually more accurate, dexterous, and functionally quicker than non-dominant hands. The index finger was superior to the little finger in the finger tapping counts (p < 0.05). Also, FPS was greater in the index finger than in the middle finger (p < 0.05). The HGS of dominant hands was significantly stronger than that of non-dominant hands (p < 0.05). When the normative data were compared with the data of shipyard workers exposed to vibration, there were statistically significant differences in VPT and neuromuscular functions. The current data can be used to evaluate HAVS in Korean male workers. Age is an important factor for VPT.

Modeling of biodynamic responses distributed at the fingers and the palm of the human hand-arm system.

PubMed

Dong, Ren G; Dong, Jennie H; Wu, John Z; Rakheja, Subhash

2007-01-01

The objective of this study is to develop analytical models for simulating driving-point biodynamic responses distributed at the fingers and palm of the hand under vibration along the forearm direction (z(h)-axis). Two different clamp-like model structures are formulated to analyze the distributed responses at the fingers-handle and palm-handle interfaces, as opposed to the single driving point invariably considered in the reported models. The parameters of the proposed four- and five degrees-of-freedom models are identified through minimization of an rms error function of the model and measured responses under different hand actions, namely, fingers pull, push only, grip only, and combined push and grip. The results show that the responses predicted from both models agree reasonably well with the measured data in terms of distributed as well total impedance magnitude and phase. The variations in the identified model parameters under different hand actions are further discussed in view of the biological system behavior. The proposed models are considered to serve as useful tools for design and assessment of vibration isolation methods, and for developing a hand-arm simulator for vibration analysis of power tools.

A comparison of hand-arm vibration syndrome between Malaysian and Japanese workers.

PubMed

Su, Anselm Ting; Fukumoto, Jin; Darus, Azlan; Hoe, Victor C W; Miyai, Nobuyuki; Isahak, Marzuki; Takemura, Shigeki; Bulgiba, Awang; Yoshimasu, Kouichi; Maeda, Setsuo; Miyashita, Kazuhisa

2013-01-01

The aim of this study was to investigate the clinical characteristics of HAVS in a tropical environment in comparison with a temperate environment. We conducted a series medical examinations among the forestry, construction and automobile industry workers in Malaysia adopting the compulsory medical examination procedure used by Wakayama Medical University for Japanese vibratory tools workers. We matched the duration of vibration exposure and compared our results against the Japanese workers. We also compared the results of the Malaysian tree fellers against a group of symptomatic Japanese tree fellers diagnosed with HAVS. Malaysian subjects reported a similar prevalence of finger tingling, numbness and dullness (Malaysian=25.0%, Japanese=21.5%, p=0.444) but had a lower finger skin temperature (FST) and higher vibrotactile perception threshold (VPT) values as compared with the Japanese workers. No white finger was reported in Malaysian subjects. The FST and VPT of the Malaysian tree fellers were at least as bad as the Japanese tree fellers despite a shorter duration (mean difference=20.12 years, 95%CI=14.50, 25.40) of vibration exposure. Although the vascular disorder does not manifest clinically in the tropical environment, the severity of HAVS can be as bad as in the temperate environment with predominantly neurological disorder. Hence, it is essential to formulate national legislation for the control of the occupational vibration exposure.

Vibration and impulsivity analysis of hand held olive beaters.

PubMed

Deboli, Roberto; Calvo, Angela; Preti, Christian

2016-07-01

To provide more effective evaluations of hand arm vibration syndromes caused by hand held olive beaters, this study focused on two aspects: the acceleration measured at the tool pole and the analysis of the impulsivity, using the crest factor. The signals were frequency weighted using the weighting curve Wh as described in the ISO 5349-1 standard. The same source signals were also filtered by the Wh-bl filter (ISO/TS 15694), because the weighting filter Wh (unlike the Wh-bl filter) could underestimate the effect of high frequency vibration on vibration-induced finger disorders. Ten (experienced) male operators used three beater models (battery powered) in the real olive harvesting condition. High vibration total values were obtained with values never lower than 20 m(-2). Concerning the crest factor, the values ranged from 5 to more than 22. This work demonstrated that the hand held olive beaters produced high impulsive loads comparable to the industry hand held tools. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Work-related risk factors for specific shoulder disorders: a systematic review and meta-analysis.

PubMed

van der Molen, Henk F; Foresti, Chiara; Daams, Joost G; Frings-Dresen, Monique H W; Kuijer, P Paul F M

2017-10-01

The objective of this systematic review and meta-analysis is to examine which work-related risk factors are associated with specific soft tissue shoulder disorders. We searched the electronic databases of Medline and Embase for articles published between 2009 and 24 March 2016 and included the references of a systematic review performed for the period before 2009. Primary cross-sectional and longitudinal studies were included when outcome data were described in terms of clinically assessed soft tissue shoulder disorders and at least two levels of work-related exposure were mentioned (exposed vs less or non-exposed). Two authors independently selected studies, extracted data and assessed study quality. For longitudinal studies, we performed meta-analyses and used GRADE (Grades of Recommendations, Assessment, Development and Evaluation) to assess the evidence for the associations between risk factors and the onset of shoulder disorders. Twenty-seven studies met the inclusion criteria. In total, 16 300 patients with specific soft tissue shoulder disorders from a population of 2 413 722 workers from Denmark, Finland, France, Germany and Poland were included in the meta-analysis of one case-control and six prospective cohort studies. This meta-analysis revealed moderate evidence for associations between shoulder disorders and arm-hand elevation (OR=1.9, 95% CI 1.47 to 2.47) and shoulder load (OR=2.0, 95% CI 1.90 to 2.10) and low to very low evidence for hand force exertion (OR=1.5, 95% CI 1.25 to 1.87), hand-arm vibration (OR=1.3, 95% CI 1.01 to 1.77), psychosocial job demands (OR=1.1, 95% CI 1.01 to 1.25) and working together with temporary workers (OR=2.2, 95% CI 1.2 to 4.2). Low-quality evidence for no associations was found for arm repetition, social support, decision latitude, job control and job security. Moderate evidence was found that arm-hand elevation and shoulder load double the risk of specific shoulder disorders. Low to very-low-quality evidence was found for an association between hand force exertion, hand-arm vibration, psychosocial job demands and working together with temporary workers and the incidence of specific shoulder disorders. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A Comparison of Image Quality and Radiation Exposure Between the Mini C-Arm and the Standard C-Arm.

PubMed

van Rappard, Juliaan R M; Hummel, Willy A; de Jong, Tijmen; Mouës, Chantal M

2018-04-01

The use of intraoperative fluoroscopy has become mandatory in osseous hand surgery. Due to its overall practicality, the mini C-arm has gained popularity among hand surgeons over the standard C-arm. This study compares image quality and radiation exposure for patient and staff between the mini C-arm and the standard C-arm, both with flat panel technology. An observer-based subjective image quality study was performed using a contrast detail (CD) phantom. Five independent observers were asked to determine the smallest circles discernable to them. The results were plotted in a graph, forming a CD curve. From each curve, an image quality figure (IQF) was derived. A lower IQF equates to a better image quality. The patients' entrance skin dose was measured, and to obtain more information about the staff exposure dose, a perspex hand phantom was used. The scatter radiation was measured at various distances and angles relative to a central point on the detector. The IQF was significantly lower for the mini C-arm resulting in a better image quality. The patients' entrance dose was 10 times higher for the mini C-arm as compared with the standard C-arm, and the scatter radiation threefold. Due to its improved image quality and overall practicality, the mini C-arm is recommended for hand surgical procedures. To ensure that the surgeons' radiation exposure is not exceeding the safety limits, monitoring radiation exposure using mini C-arms with flat panel technology during surgery should be done in a future clinical study.

Hand-arm vibration syndrome: clinical characteristics, conventional electrophysiology and quantitative sensory testing.

PubMed

Rolke, Roman; Rolke, Silke; Vogt, Thomas; Birklein, Frank; Geber, Christian; Treede, Rolf-Detlef; Letzel, Stephan; Voelter-Mahlknecht, Susanne

2013-08-01

Workers exposed to vibrating tools may develop hand-arm vibration syndrome (HAVS). We assessed the somatosensory phenotype using quantitative sensory testing (QST) in comparison to electrophysiology to characterize (1) the most sensitive QST parameter for detecting sensory loss, (2) the correlation of QST and electrophysiology, and (3) the frequency of a carpal tunnel syndrome (CTS) in HAVS. QST, cold provocation tests, fine motor skills, and median nerve neurography were used. QST included thermal and mechanical detection and pain thresholds. Thirty-two patients were examined (54 ± 11 years, 91% men) at the more affected hand compared to 16 matched controls. Vibration detection threshold was the most sensitive parameter to detect sensory loss that was more pronounced in the sensitivity range of Pacinian (150 Hz, x12) than Meissner's corpuscles (20 Hz, x3). QST (84% abnormal) was more sensitive to detect neural dysfunction than conventional electrophysiology (37% abnormal). Motor (34%) and sensory neurography (25%) were abnormal in HAVS. CTS frequency was not increased (9.4%). Findings are consistent with a mechanically-induced, distally pronounced motor and sensory neuropathy independent of CTS. HAVS involves a neuropathy predominantly affecting large fibers with a sensory damage related to resonance frequencies of vibrating tools. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Relationship between self-reported upper limb disability and quantitative tests in hand-arm vibration syndrome.

PubMed

Poole, Kerry; Mason, Howard

2007-03-15

To establish the relationship between quantitative tests of hand function and upper limb disability, as measured by the Disability of the Arm, Shoulder and Hand (DASH) questionnaire, in hand-arm vibration syndrome (HAVS). A total of 228 individuals with HAVS were included in this study. Each had undergone a full HAVS assessment by an experienced physician, including quantitative tests of vibrotactile and thermal perception thresholds, maximal hand-grip strength (HG) and the Purdue pegboard (PP) test. Individuals were also asked to complete a DASH questionnaire. PP and HG of the quantitative tests gave the best and statistically significant individual correlations with the DASH disability score (r2 = 0.168 and 0.096). Stepwise linear regression analysis revealed that only PP and HG measurements were statistically significant predictors of upper limb disability (r2 = 0.178). Overall a combination of the PP and HG measurements, rather than each alone, gave slightly better discrimination, although not statistically significant, between normal and abnormal DASH scores with a sensitivity of 73.1% and specificity of 64.3%. Measurements of manual dexterity and hand-grip strength using PP and HG may be useful in helping to confirm lack of upper limb function and 'perceived' disability in HAVS.

The sensitivity and specificity of thermometry and plethysmography in the assessment of hand-arm vibration syndrome.

PubMed

Thompson, Aaron; House, Ron; Manno, Michael

2008-05-01

Finger plethysmography and thermometry are objective measures used to assess the vascular aspect of hand-arm vibration syndrome (HAVS). Research to date shows poor correlation between these tests and Stockholm Workshop Scale (SWS) vascular stage. Clinicians, researchers and compensation boards require objective means to diagnose and quantify HAVS. To define the specificity and sensitivity of thermometry and plethysmography using the SWS as the reference criterion. A secondary goal was to consider cut points for the tests optimizing sensitivity and specificity. A cross-sectional analysis was conducted on HAVS patients seen at an occupational medicine specialty clinic. Plethysmography and thermometry were analyzed using SWS vascular stage as the outcome variable. Logistic regression controlled for age, smoking and time since last vibration exposure and use of vasoactive medications. The sensitivity and specificity of the combined tests were calculated using varying cut points. A total of 139 patients consented to participate in the study. Plethysmography stage 1 or greater showed the highest sensitivity (sensitivity 94% and specificity 15%). Specificity was optimized combining plethysmography stage 3 and thermometry stage 3 (specificity 98% and sensitivity 23%). Maximal diagnostic accuracy was achieved by plethysmography alone setting the criteria for a positive test as being stage 1 or greater (70%). Neither plethysmography nor thermometry either alone or in combination demonstrated sufficient sensitivity and specificity to serve as an objective correlate for SWS vascular stage. All combinations of plethysmography and thermometry showed a lower specificity than sensitivity indicating that the SWS may be less sensitive in detecting vascular pathology than the objective tests.

Delivery of health surveillance for hand-arm vibration in the West Midlands.

PubMed

Kinoulty, Mary

2006-01-01

Concerns about provider competence and quality of hand-arm vibrations (HAVs) health surveillance programmes were identified by Health & Safety Executive (HSE) inspectors. To evaluate health surveillance programmes and compare them with published HSE guidance. To identify deficiencies and areas for improvement in the health surveillance programmes. A proforma was developed for the study and used on a sample of 10 local occupational health providers. All 10 organizations were aware of current HSE guidance for health surveillance for HAVs but only a minority (30%) were following it. Occupational health provider training, written procedures and health surveillance delivery were all identified as areas requiring improvement. The majority of organizations were not following HSE guidance. Occupational health providers undertaking health surveillance for HAV require specific training.

[Measurement and analysis of hand-transmitted vibration of vibration tools in workplace for automobile casting and assembly].

PubMed

Xie, X S; Qi, C; Du, X Y; Shi, W W; Zhang, M

2016-02-20

To investigate the features of hand-transmitted vibration of common vibration tools in the workplace for automobile casting and assembly. From September to October, 2014, measurement and spectral analysis were performed for 16 typical hand tools(including percussion drill, pneumatic wrench, grinding machine, internal grinder, and arc welding machine) in 6 workplaces for automobile casting and assembly according to ISO 5349-1-2001 Mechanical vibration-Measurement and evaluation of human exposure to hand-transmitted vibration-part 1: General requirements and ISO 5349-2-2001 Mechanical vibration-Measurement and evaluation of human exposure to hand-transmitted vibration-Part 2: Practical guidance for measurement in the workplace. The vibration acceleration waveforms of shearing machine, arc welding machine, and pneumatic wrench were mainly impact wave and random wave, while those of internal grinder, angle grinder, percussion drill, and grinding machine were mainly long-and short-period waves. The daily exposure duration to vibration of electric wrench, pneumatic wrench, shearing machine, percussion drill, and internal grinder was about 150 minutes, while that of plasma cutting machine, angle grinder, grinding machine, bench grinder, and arc welding machine was about 400 minutes. The range of vibration total value(ahv) was as follows: pneumatic wrench 0.30~11.04 m/s(2), grinding wheel 1.61~8.97 m/s(2), internal grinder 1.46~8.70 m/s(2), percussion drill 11.10~14.50 m/s(2), and arc welding machine 0.21~2.18 m/s(2). The workers engaged in cleaning had the longest daily exposure duration to vibration, and the effective value of 8-hour energy-equivalent frequency-weighted acceleration for them[A(8)] was 8.03 m/s(2), while this value for workers engaged in assembly was 4.78 m/s(2). The frequency spectrogram with an 1/3-time frequency interval showed that grinding machine, angle grinder, and percussion drill had a high vibration acceleration, and the vibration limit curve was recommended for those with a frequency higher than 400 min/d. The workers who are engaged in cleaning, grinding, and a few positions of assembly and use grinding machine, angle grinder, internal grinder, and percussion drill are exposed to vibrations with a high vibration acceleration and at a high position of the frequency spectrum. The hand-transmitted vibration in the positions of cutting, polishing, and cleaning in automobile casting has great harm, and the harm caused by pneumatic wrench in automobile assembly should be taken seriously.

White fingers, cold environment, and vibration--exposure among Swedish construction workers.

PubMed

Burström, Lage; Järvholm, Bengt; Nilsson, Tohr; Wahlström, Jens

2010-11-01

The aim of this study was to examine the association between white fingers, cold environment, and exposure to hand-arm vibration (HAV). The hypothesis was that working in cold climate increases the risk of white fingers. The occurrence of white fingers was investigated as a cross-sectional study in a cohort of Swedish male construction workers (N=134 757). Exposure to HAV was based on a job-exposure matrix. Living in the north or south of Sweden was, in a subgroup of the cohort, used as an indicator of the exposure to cold environment (ie, living in the north meant a higher exposure to cold climate). The analyses were adjusted for age and use of nicotine products (smoking and snuff). HAV-exposed workers living in a colder climate had a higher risk for white fingers than those living in a warmer climate [odds ratio (OR) 1.71, 95% confidence interval (95% CI) 1.42-2.06]. As expected, we found that HAV-exposed workers had an increased risk compared to controls (OR 2.02, 95% CI 1.75-2.34). The risk for white fingers increased with increased level of exposure to HAV and also age. Cold environment increases the risk for white fingers in workers occupationally exposed to HAV. The results underscore the need to keep exposure to HAV at workplaces as low as possible especially in cold climate.

No Telescoping Effect with Dual Tendon Vibration

PubMed Central

Bellan, Valeria; Wallwork, Sarah B.; Stanton, Tasha R.; Reverberi, Carlo; Gallace, Alberto; Moseley, G. Lorimer

2016-01-01

The tendon vibration illusion has been extensively used to manipulate the perceived position of one’s own body part. However, findings from previous research do not seem conclusive sregarding the perceptual effect of the concurrent stimulation of both agonist and antagonist tendons over one joint. On the basis of recent data, it has been suggested that this paired stimulation generates an inconsistent signal about the limb position, which leads to a perceived shrinkage of the limb. However, this interesting effect has never been replicated. The aim of the present study was to clarify the effect of a simultaneous and equal vibration of the biceps and triceps tendons on the perceived location of the hand. Experiment 1 replicated and extended the previous findings. We compared a dual tendon stimulation condition with single tendon stimulation conditions and with a control condition (no vibration) on both ‘upward-downward’ and ‘towards-away from the elbow’ planes. Our results show a mislocalisation towards the elbow of the position of the vibrated arm during dual vibration, in line with previous results; however, this did not clarify whether the effect was due to arm representation contraction (i.e., a ‘telescoping’ effect). Therefore, in Experiment 2 we investigated explicitly and implicitly the perceived arm length during the same conditions. Our results clearly suggest that in all the vibration conditions there was a mislocalisation of the entire arm (including the elbow), but no evidence of a contraction of the perceived arm length. PMID:27305112

No Telescoping Effect with Dual Tendon Vibration.

PubMed

Bellan, Valeria; Wallwork, Sarah B; Stanton, Tasha R; Reverberi, Carlo; Gallace, Alberto; Moseley, G Lorimer

2016-01-01

The tendon vibration illusion has been extensively used to manipulate the perceived position of one's own body part. However, findings from previous research do not seem conclusive sregarding the perceptual effect of the concurrent stimulation of both agonist and antagonist tendons over one joint. On the basis of recent data, it has been suggested that this paired stimulation generates an inconsistent signal about the limb position, which leads to a perceived shrinkage of the limb. However, this interesting effect has never been replicated. The aim of the present study was to clarify the effect of a simultaneous and equal vibration of the biceps and triceps tendons on the perceived location of the hand. Experiment 1 replicated and extended the previous findings. We compared a dual tendon stimulation condition with single tendon stimulation conditions and with a control condition (no vibration) on both 'upward-downward' and 'towards-away from the elbow' planes. Our results show a mislocalisation towards the elbow of the position of the vibrated arm during dual vibration, in line with previous results; however, this did not clarify whether the effect was due to arm representation contraction (i.e., a 'telescoping' effect). Therefore, in Experiment 2 we investigated explicitly and implicitly the perceived arm length during the same conditions. Our results clearly suggest that in all the vibration conditions there was a mislocalisation of the entire arm (including the elbow), but no evidence of a contraction of the perceived arm length.

Control Model for Dampening Hand Vibrations Using Information of Internal and External Coordinates

PubMed Central

Togo, Shunta; Kagawa, Takahiro; Uno, Yoji

2015-01-01

In the present study, we investigate a control mechanism that dampens hand vibrations. Here, we propose a control method with two components to suppress hand vibrations. The first is a passive suppression method that lowers the joint stiffness to passively dampen the hand vibrations. The second is an active suppression method that adjusts an equilibrium point based on skyhook control to actively dampen the hand vibrations. In a simulation experiment, we applied these two methods to dampen hand vibrations during the shoulder’s horizontal oscillation. We also conducted a measurement experiment wherein a subject’s shoulder was sinusoidally oscillated by a platform that generated horizontal oscillations. The results of the measurement experiments showed that the jerk of each part of the arm in a task using a cup filled with water was smaller than the shoulder jerk and that in a task with a cup filled with stones was larger than the shoulder jerk. Moreover, the amplitude of the hand trajectory in both horizontal and vertical directions was smaller in a task using a cup filled with water than in a task using a cup filled with stones. The results of the measurement experiments were accurately reproduced by the active suppression method based on skyhook control. These results suggest that humans dampen hand vibrations by controlling the equilibrium point through the information of the external workspace and the internal body state rather than by lowering joint stiffness only by using internal information. PMID:25876037

[Features of peripheral nerve injuries in workers exposed to vibration: an analysis of 197 cases].

PubMed

Situ, J; Lin, C M; Qin, Z H; Zhu, D X; Lin, H; Zhang, F F; Zhang, J J

2016-12-20

Objective: To investigate the features of peripheral nerve injuries in workers exposed to vibration. Methods: A total of 197 male workers [median age: 34 years (21 - 50 years) ; median working years of vibration exposure: 7.3 years (1 - 20 years) ] engaged in grinding in an enterprise were enrolled. Their clinical data and electromyography results were analyzed to investigate the features of peripheral nerve impairment. Results: Of all workers, 96 (48.73%) had abnormal electromyography results. Of all workers, 88 (44.7%) had simple mild median nerve injury in the wrist, who accounted for 91.7% (88/96) of all workers with abnormal electromy-ography results. Six workers had ulnar nerve injury, superficial radial nerve injury, or/and superficial peroneal nerve injury and accounted for 6.3% of all workers with abnormal electromyography results. Of all workers, 88 had a reduced amplitude of median nerve sensory transduction, and 28 had slowed median nerve sensory transduction. A total of 46 workers were diagnosed with occupational hand-arm vibration disease and hospitalized for treatment. They were followed up for more than 4 months after leaving their jobs, and most of them showed improvements in neural electromyography results and returned to a normal state. Conclusion: Workers exposed to vibration have a high incidence rate of nerve injury in the hand, mainly sensory function impairment at the distal end of the median nerve, and all injuries are mild peripheral nerve injuries. After leaving the vibration job and being treated, most workers can achieve improvements and return to a normal state.

Intensified hand-hygiene campaign including soap-and-water wash may prevent acute infections in office workers, as shown by a recognized-exposure -adjusted analysis of a randomized trial.

PubMed

Hovi, Tapani; Ollgren, Jukka; Savolainen-Kopra, Carita

2017-01-09

Variable exposure to causative agents of acute respiratory (RTI) or gastrointestinal tract infections (GTI) is a significant confounding factor in the analysis of the efficacy of interventions concerning these infections. We had an exceptional opportunity to reanalyze a previously published dataset from a trial assessing the effect of enhanced hand hygiene on the occurrence of RTI or GTI in adults, after adjustment for reported exposure and other covariates. Twenty-one working units (designated clusters) each including at least 50 office employees, totaling 1,270 persons, were randomized into two intervention arms (either using water-and-soap or alcohol-rub in hand cleansing), or in the control arm. Self-reported data was collected through weekly emails and included own symptoms of RTI or GTI, and exposures to other persons with similar symptoms. Differences in the weekly occurrences of RTI and GTI symptoms between the arms were analyzed using multilevel binary regression model with log link with personal and cluster specific random effects, self-reported exposure to homologous disease, randomization triplet, and seasonality as covariates in the Bayesian framework. Over the 16 months duration of the trial, 297 persons in the soap and water arm, 238 persons in the alcohol-based hand rub arm, and 230 controls sent reports. The arms were similar in age distribution and gender ratios. A temporally-associated reported exposure strongly increased the risk of both types of infection in all trial arms. Persons in the soap-and-water arm reported a significantly - about 24% lower weekly prevalence of GTI than the controls whether they had observed an exposure or not during the preceding week, while for RTI, this intervention reduced the prevalence only during weeks without a reported exposure. Alcohol-rub did not affect the symptom prevalence. We conclude that while frequent and careful hand washing with soap and water partially protected office-working adults from GTI, the effect on RTI was only marginal in this study. Potential reasons for this difference include partially different transmission routes and a difference in the virus load. In this trial, frequent standardized hand rubbing with ethanol-based disinfectant did not reduce the weekly prevalence of either type of infections. ClinicalTrials.gov Identifier: NCT00821509, 12 March 2009.

Work environment and safety climate in the Swedish merchant fleet.

PubMed

Forsell, Karl; Eriksson, Helena; Järvholm, Bengt; Lundh, Monica; Andersson, Eva; Nilsson, Ralph

2017-02-01

To get knowledge of the work environment for seafarers sailing under the Swedish flag, in terms of safety climate, ergonomical, chemical and psychosocial exposures, and the seafarers self-rated health and work ability. A Web-based questionnaire was sent to all seafarers with a personal e-mail address in the Swedish Maritime Registry (N = 5608). Comparisons were made mainly within the study population, using Student's t test, prevalence odds ratios and logistic regressions with 95% confidence intervals. The response rate was 35% (N = 1972; 10% women, 90% men), with 61% of the respondents working on deck, 31% in the engine room and 7% in the catering/service department (1% not classifiable). Strain on neck, arm or back and heavy lifting were associated with female gender (p = 0.0001) and younger age (below or above 30 years of age, p < 0.0001). Exposures to exhausts, oils and dust were commonly reported. Major work problems were noise, risk of an accident and vibrations from the hull of the ship. The safety climate was high in comparison with that in land-based occupations. One-fourth had experienced personal harassment or bullying during last year of service. Noise, risk of accidents, hand/arm and whole-body vibrations and psychosocial factors such as harassment were commonly reported work environment problems among seafarers within the Swedish merchant fleet.

Human response to vibration stress in Japanese workers: lessons from our 35-year studies A narrative review

PubMed Central

MATOBA, Tsunetaka

2015-01-01

The occupational uses with vibratory tools or vehicles provoked health disorders of users. We reviewed narratively our articles of 35 yr studies and their related literatures, and considered the pathophysiology of the hand-arm vibration disorders. Concerning the risk factors of health impairments in workers with vibratory tools, there are two conflicting schools of the researchers: The peripheral school emphasizes that vibration only makes predominant impairments on hands and arms, showing typically Raynaud’s phenomenon in the fingers. In the systemic school, the health disorders are produced by combination with vibration, noise and working environment, namely vibratory work itself, leading to diversified symptoms and signs in relation to systemic impairments. Our 35 yr studies have evidently supported the systemic school, including disorders of the central and autonomic nervous systems. The genesis is vibratory work itself, including vibration, noise, cold working environment, ergonomic and biodynamic conditions, and emotional stress in work. Because the health disorders yield in the whole body, the following measures would contribute to the prevention of health impairments: the attenuation of vibration and noise generated form vibratory machines and the regulations on operating tool hours. In conclusion, this occupational disease results from systemic impairments due to long-term occupational work with vibratory tools. PMID:26460379

Human response to vibration stress in Japanese workers: lessons from our 35-year studies A narrative review.

PubMed

Matoba, Tsunetaka

2015-01-01

The occupational uses with vibratory tools or vehicles provoked health disorders of users. We reviewed narratively our articles of 35 yr studies and their related literatures, and considered the pathophysiology of the hand-arm vibration disorders. Concerning the risk factors of health impairments in workers with vibratory tools, there are two conflicting schools of the researchers: The peripheral school emphasizes that vibration only makes predominant impairments on hands and arms, showing typically Raynaud's phenomenon in the fingers. In the systemic school, the health disorders are produced by combination with vibration, noise and working environment, namely vibratory work itself, leading to diversified symptoms and signs in relation to systemic impairments. Our 35 yr studies have evidently supported the systemic school, including disorders of the central and autonomic nervous systems. The genesis is vibratory work itself, including vibration, noise, cold working environment, ergonomic and biodynamic conditions, and emotional stress in work. Because the health disorders yield in the whole body, the following measures would contribute to the prevention of health impairments: the attenuation of vibration and noise generated form vibratory machines and the regulations on operating tool hours. In conclusion, this occupational disease results from systemic impairments due to long-term occupational work with vibratory tools.

Minimum health and safety requirements for workers exposed to hand-transmitted vibration and whole-body vibration in the European Union; a review

PubMed Central

Griffin, M

2004-01-01

In 2002, the Parliament and Commission of the European Community agreed "minimum health and safety requirements" for the exposure of workers to the risks arising from vibration. The Directive defines qualitative requirements and also quantitative requirements in the form of "exposure action values" and "exposure limit values". The quantitative guidance is based on, but appears to conflict with, the guidance in International Standards for hand-transmitted vibration (ISO 5349) and whole-body vibration (ISO 2631). There is a large internal inconsistency within the Directive for short duration exposures to whole-body vibration: the two alternative methods give very different values. It would appear prudent to base actions on the qualitative guidance (i.e. reducing risk to a minimum) and only refer to the quantitative guidance where there is no other reasonable basis for the identification of risk (i.e. similar exposures are not a suspected cause of injury). Health surveillance and other precautions will be appropriate wherever there is reason to suspect a risk and will not be restricted to conditions where the exposure action value is exceeded. PMID:15090658

Power tiller: vibration magnitudes and intervention development for vibration reduction.

PubMed

Chaturvedi, Varun; Kumar, Adarsh; Singh, J K

2012-09-01

The operators of power tiller are exposed to a high level of vibration originating from the dynamic interaction between the soil and the machine. The vibration from the power tiller is transmitted from the handle to hands, arms and shoulders. In the present study, experiments were conducted in three operational conditions i.e. transportation on farm roads, tilling with cultivator and rota-tilling with rota-vator. The highest vibration values were observed in x-direction in all the experiments. The maximum vibration rms values for x-direction were 5.96, 6.81 and 8.00 ms(-2) in tilling with cultivator, transportation and rota-tilling respectively. Three materials were used for intervention development to reduce vibration magnitude. The maximum reduction of 25.30, 31.21 and 30.45% in transportation; 23.50, 30.64 and 20.86% in tilling with cultivator and 24.03, 29.18 and 25.52% in rota-tilling were achieved with polyurethane (PU), rubber and combination of PU and rubber intervention. It was found that the maximum vibration reductions were achieved with the rubber in all three operational conditions. The average exposure time for occurrence of white finger syndrome increased by 28-50% with incorporation of intervention in different operations. Physiological and postural parameters also improved with incorporation of interventions. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Effect of bit wear on hammer drill handle vibration and productivity.

PubMed

Antonucci, Andrea; Barr, Alan; Martin, Bernard; Rempel, David

2017-08-01

The use of large electric hammer drills exposes construction workers to high levels of hand vibration that may lead to hand-arm vibration syndrome and other musculoskeletal disorders. The aim of this laboratory study was to investigate the effect of bit wear on drill handle vibration and drilling productivity (e.g., drilling time per hole). A laboratory test bench system was used with an 8.3 kg electric hammer drill and 1.9 cm concrete bit (a typical drill and bit used in commercial construction). The system automatically advanced the active drill into aged concrete block under feed force control to a depth of 7.6 cm while handle vibration was measured according to ISO standards (ISO 5349 and 28927). Bits were worn to 4 levels by consecutive hole drilling to 4 cumulative drilling depths: 0, 1,900, 5,700, and 7,600 cm. Z-axis handle vibration increased significantly (p<0.05) from 4.8 to 5.1 m/s 2 (ISO weighted) and from 42.7-47.6 m/s 2 (unweighted) when comparing a new bit to a bit worn to 1,900 cm of cumulative drilling depth. Handle vibration did not increase further with bits worn more than 1900 cm of cumulative drilling depth. Neither x- nor y-axis handle vibration was effected by bit wear. The time to drill a hole increased by 58% for the bit with 5,700 cm of cumulative drilling depth compared to a new bit. Bit wear led to a small but significant increase in both ISO weighted and unweighted z-axis handle vibration. Perhaps more important, bit wear had a large effect on productivity. The effect on productivity will influence a worker's allowable daily drilling time if exposure to drill handle vibration is near the ACGIH Threshold Limit Value. [1] Construction contractors should implement a bit replacement program based on these findings.

Investigation of human body vibration exposures on haul trucks operating at U.S. surface mines/quarries relative to haul truck activity.

PubMed

Mayton, Alan G; Porter, William L; Xu, Xueyan S; Weston, Eric B; Rubenstein, Elaine N

2018-03-01

Workers who operate mine haul trucks are exposed to whole-body vibration (WBV) on a routine basis. Researchers from the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) investigated WBV and hand-arm vibration (HAV) exposures for mine/quarry haul truck drivers in relation to the haul truck activities of dumping, loading, and traveling with and without a load. The findings show that WBV measures in weighted root-mean-square accelerations (a w ) and vibration dose value (VDV), when compared to the ISO/ANSI and European Directive 2002/44/EC standards, were mostly below the Exposure Action Value (EAV) identified by the health guidance caution zone (HGCZ). Nevertheless, instances were recorded where the Exposure Limit Value (ELV) was exceeded by more than 500 to 600 percent for VDV x and a wx , respectively. Researchers determined that these excessive levels occurred during the traveling empty activity, when the haul truck descended down grade into the pit loading area, sliding at times, on a wet and slippery road surface caused by rain and overwatering. WBV levels (not normalized to an 8-h shift) for the four haul truck activities showed mean a wz levels for five of the seven drivers exceeding the ISO/ANSI EAV by 9-53 percent for the traveling empty activity. Mean a wx and a wz levels were generally higher for traveling empty and traveling loaded and lower for loading/dumping activities. HAV for measures taken on the steering wheel and shifter were all below the HGCZ which indicates that HAV is not an issue for these drivers/operators when handling steering and shifting control devices.

Investigation of human body vibration exposures on haul trucks operating at U.S. surface mines/quarries relative to haul truck activity

PubMed Central

Mayton, Alan G.; Porter, William L.; Xu, Xueyan S.; Weston, Eric B.; Rubenstein, Elaine N.

2018-01-01

Workers who operate mine haul trucks are exposed to whole-body vibration (WBV) on a routine basis. Researchers from the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) investigated WBV and hand-arm vibration (HAV) exposures for mine/quarry haul truck drivers in relation to the haul truck activities of dumping, loading, and traveling with and without a load. The findings show that WBV measures in weighted root-mean-square accelerations (aw) and vibration dose value (VDV), when compared to the ISO/ANSI and European Directive 2002/44/EC standards, were mostly below the Exposure Action Value (EAV) identified by the health guidance caution zone (HGCZ). Nevertheless, instances were recorded where the Exposure Limit Value (ELV) was exceeded by more than 500 to 600 percent for VDVx and awx, respectively. Researchers determined that these excessive levels occurred during the traveling empty activity, when the haul truck descended down grade into the pit loading area, sliding at times, on a wet and slippery road surface caused by rain and overwatering. WBV levels (not normalized to an 8-h shift) for the four haul truck activities showed mean awz levels for five of the seven drivers exceeding the ISO/ANSI EAV by 9–53 percent for the traveling empty activity. Mean awx and awz levels were generally higher for traveling empty and traveling loaded and lower for loading/dumping activities. HAV for measures taken on the steering wheel and shifter were all below the HGCZ which indicates that HAV is not an issue for these drivers/operators when handling steering and shifting control devices. PMID:29725145

Short-Term Effects of Whole-Body Vibration Combined with Task-Related Training on Upper Extremity Function, Spasticity, and Grip Strength in Subjects with Poststroke Hemiplegia: A Pilot Randomized Controlled Trial.

PubMed

Lee, Jung-Sun; Kim, Chang-Yong; Kim, Hyeong-Dong

2016-08-01

The aim of this study was to determine the effect of whole-body vibration training combined with task-related training on arm function, spasticity, and grip strength in subjects with poststroke hemiplegia. Forty-five subjects with poststroke were randomly allocated to 3 groups, each with 15 subjects as follows: control group, whole-body vibration group, and whole-body vibration plus task-related training group. Outcome was evaluated by clinical evaluation and measurements of the grip strength before and 4 weeks after intervention. Our results show that there was a significantly greater increase in the Fugl-Meyer scale, maximal grip strength of the affected hand, and grip strength normalized to the less affected hand in subjects undergoing the whole-body vibration training compared with the control group after the test. Furthermore, there was a significantly greater increase in the Wolf motor function test and a decrease in the modified Ashworth spasticity total scores in subjects who underwent whole-body vibration plus task-related training compared with those in the other 2 groups after the test. The findings indicate that the use of whole-body vibration training combined with task-related training has more benefits on the improvement of arm function, spasticity, and maximal grip strength than conventional upper limb training alone or with whole-body vibration in people with poststroke hemiplegia.

[Magnetic resonance imaging for the wrist joint of the coal miners in vibration department].

PubMed

Zhao, Xuan-zhi; Liu, Rui-lian; Hu, Shu-dong; Zhang, Wei; Xu, Wen-xiu; Ge, Ling-xia

2006-04-01

To study the magnetic resonance imaging (MRI) in the wrist joint of coal miners who work in excavation and vibration department. Forty-three coal miners with the hand-arm vibration disease served as the observation group while 20 workers who were not working in the vibration department acted as the control group. The patients in the observation group were divided into five subgroups according to the time when they received vibration. The regularity of the development of signs and symptoms of MRI was observed and analyzed. The hydroarthrosis was most found in MRI. There were significant difference in hydroarthrosis (chi(2) = 8.80, P < 0.01), osteoporosis and osteomyelitis (chi(2) = 3.91, chi(2) = 5.01, P < 0.05 respectively) between the observation group and the control group. The edema of bone marrow and the avascular necrosis of ossa carpi were found only in the observation group and not found in the control group. The hydroarthrosis and the edema of bone marrow occurred most in the early stage of vibration. The signal in the edema of the bone marrow of the distal end of the radius was decreased in the GE sequence T(2)WI with the specificity. (1) Changes in the wrist joint occur in the early stage of the vibration work, and can be found in the MRI. (2) The edema of the bone marrow of the distal end of the radius is of great value in the diagnosis of the hand-arm vibration disease.

Cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome: a nationwide Danish cohort study.

PubMed

Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid; Svendsen, Susanne Wulff

2014-11-01

The primary aim was to examine exposure-response relationships between cumulative occupational shoulder exposures and surgery for subacromial impingement syndrome (SIS), and to compare sex-specific exposure-response relationships. The secondary aim was to examine the time window of relevant exposures. We conducted a nationwide register study of all persons born in Denmark (1933-1977), who had at least 5 years of full-time employment. In the follow-up period (2003-2008), we identified first-time events of surgery for SIS. Cumulative exposure estimates for a 10-year exposure time window with a 1-year lag time were obtained by linking occupational codes with a job exposure matrix. The exposure estimates were expressed as, for example, arm-elevation-years in accordance with the pack-year concept of tobacco consumption. We used a multivariable logistic regression technique equivalent to discrete survival analysis. The adjusted OR (ORadj) increased to a maximum of 2.1 for arm-elevation-years, repetition-years and force-years, and to 1.5 for hand-arm-vibration-years. Sex-specific exposure-response relationships were similar for men and women, when assessed using a relative risk scale. The ORadj increased gradually with the number of years contributing to the cumulative exposure estimates. The excess fraction was 24%. Cumulative occupational shoulder exposures carried an increase in risk of surgery for SIS with similar exposure-response curves for men and women. The risk of surgery for SIS increased gradually, when the period of exposure assessment was extended. In the general working population, a substantial fraction of all first-time operations for SIS could be related to occupational exposures. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Neck pain combined with arm pain among professional drivers of forest machines and the association with whole-body vibration exposure.

PubMed

Rehn, B; Nilsson, T; Lundström, R; Hagberg, M; Burström, L

2009-10-01

The purpose of this study was to investigate the existence of neck pain and arm pain among professional forest machine drivers and to find out if pain were related to their whole-body vibration (WBV) exposure. A self-administered questionnaire was sent to 529 forest machine drivers in northern Sweden and the response was 63%. Two pain groups were formed; 1) neck pain; 2) neck pain combined with arm pain. From WBV exposure data (recent measurements made according to ISO 2631-1, available information from reports) and from the self-administered questionnaire, 14 various WBV exposure/dose measures were calculated for each driver. The prevalence of neck pain reported both for the previous 12 months and for the previous 7 d was 34% and more than half of them reported neck pain combined with pain in one or both arms. Analysis showed no significant association between neck pain and high WBV exposure; however, cases with neck pain more often experienced shocks and jolts in the vehicle as uncomfortable. There was no significant association between the 14 WBV measures and type of neck pain (neck pain vs. neck pain combined with arm pain). It seems as if characteristics of WBV exposure can explain neither existence nor the type of neck pain amongst professional drivers of forest machines. The logging industry is important for several industrialised countries. Drivers of forest machines frequently report neuromusculoskeletal pain from the neck. The type of neck pain is important for the decision of treatment modality and may be associated with exposure characteristics at work.

Exposure level of ergonomic risk factors in hotel industries

NASA Astrophysics Data System (ADS)

Nasrull Abdol Rahman, Mohd; Syahir Muhamad Jaffar, Mohd; Fahrul Hassan, Mohd; Zamani Ngali, Mohd; Pauline, Ong

2017-08-01

Ergonomic Risk Factors (ERFs) which contribute to Musculoskeletal Disorders (MSDs) among room attendants were considered as a problem or trouble since these ERFs would affect their work performance for hotel industries. The purpose of this study was to examine the exposure level of ERFs among room attendants in hotel industries. 65 of respondents were obtained from selected hotels in Peninsular Malaysia. Data were collected by direct observation via Workplace Ergonomic Risk Assessment (WERA) and Quick Exposure Checklist (QEC). There were 36 males and 29 females room attendants involved throughout the research. Most of room attendants experienced high exposure level for back, leg, forceful and vibration based on the exposure level evaluation through WERA while QEC results showed that all room attendants were found to have moderate exposure level for risk factors including back for movement use, shoulders/arms, wrists/hands and neck. All the results obtained showed that the related ERFs for MSDs were associated and essential ergonomic interventions are needed in order to eliminate risk of exposures to MSDs among room attendants in hotel industries.

Elevated Radiation Exposure Associated With Above Surface Flat Detector Mini C-Arm Use.

PubMed

Martin, Dennis P; Chapman, Talia; Williamson, Christopher; Tinsley, Brian; Ilyas, Asif M; Wang, Mark L

2017-11-01

This study aims to test the hypothesis that: (1) radiation exposure is increased with the intended use of Flat Surface Image Intensifier (FSII) units above the operative surface compared with the traditional below-table configuration; (2) this differential increases in a dose-dependent manner; and (3) radiation exposure varies with body part and proximity to the radiation source. A surgeon mannequin was seated at a radiolucent hand table, positioned for volar distal radius plating. Thermoluminescent dosimeters measured exposure to the eyes, thyroid, chest, hand, and groin, for 1- and 15-minute trials from a mini C-arm FSII unit positioned above and below the operating surface. Background radiation was measured by control dosimeters placed within the operating theater. At 1-minute of exposure, hand and eye dosages were significantly greater with the flat detector positioned above the table. At 15-minutes of exposure, hand radiation dosage exceeded that of all other anatomic sites with the FSII in both positions. Hand exposure was increased in a dose-dependent manner with the flat detector in either position, whereas groin exposure saw a dose-dependent only with the flat detector beneath the operating table. These findings suggest that the surgeon's hands and eyes may incur greater radiation exposure compared with other body parts, during routine mini C-arm FSII utilization in its intended position above the operating table. The clinical impact of these findings remains unclear, and future long-term radiation safety investigation is warranted. Surgeons should take precautions to protect critical body parts, particularly when using FSII technology above the operating with prolonged exposure time.

Spatial resonance in a small artery excited by vibration input as a possible mechanism to cause hand-arm vascular disorders

NASA Astrophysics Data System (ADS)

Pattnaik, Shrikant; Banerjee, Rupak; Kim, Jay

2012-04-01

Hand-arm vibration syndrome (HAVS) is collectively a vasospastic and neurodegenerative occupational disease. One of the major symptoms of HAVS is vibration white finger (VWF) caused by exaggerated vasoconstriction of the arteries and skin arterioles. While VWF is a very painful and costly occupational illness, its pathology has not been well understood. In this study a small artery is modeled as a fluid filled elastic tube whose diameter changes along the axial direction. Equations of motion are developed by considering interactions between the fluid, artery wall and soft-tissue bed. It is shown that the resulting wave equation is the same as that of the basilar membrane in the cochlea of mammals. Therefore, the artery system shows a spatial resonance as in the basilar membrane, which responds with the highest amplitude at the location determined by the vibration frequency. This implies that a long-term use of one type of tool will induce high-level stresses at a few identical locations of the artery that correspond to the major frequency components of the tool. Hardening and deterioration of the artery at these locations may be a possible cause of VWF.

Laboratory and Workplace Assessments of Rivet Bucking Bar Vibration Emissions

PubMed Central

McDowell, Thomas W.; Warren, Christopher; Xu, Xueyan S.; Welcome, Daniel E.; Dong, Ren G.

2016-01-01

Sheet metal workers operating rivet bucking bars are at risk of developing hand and wrist musculoskeletal disorders associated with exposures to hand-transmitted vibrations and forceful exertions required to operate these hand tools. New bucking bar technologies have been introduced in efforts to reduce workplace vibration exposures to these workers. However, the efficacy of these new bucking bar designs has not been well documented. While there are standardized laboratory-based methodologies for assessing the vibration emissions of many types of powered hand tools, no such standard exists for rivet bucking bars. Therefore, this study included the development of a laboratory-based method for assessing bucking bar vibrations which utilizes a simulated riveting task. With this method, this study evaluated three traditional steel bucking bars, three similarly shaped tungsten alloy bars, and three bars featuring spring-dampeners. For comparison the bucking bar vibrations were also assessed during three typical riveting tasks at a large aircraft maintenance facility. The bucking bars were rank-ordered in terms of unweighted and frequency-weighted acceleration measured at the hand-tool interface. The results suggest that the developed laboratory method is a reasonable technique for ranking bucking bar vibration emissions; the lab-based riveting simulations produced similar rankings to the workplace rankings. However, the laboratory-based acceleration averages were considerably lower than the workplace measurements. These observations suggest that the laboratory test results are acceptable for comparing and screening bucking bars, but the laboratory measurements should not be directly used for assessing the risk of workplace bucking bar vibration exposures. The newer bucking bar technologies exhibited significantly reduced vibrations compared to the traditional steel bars. The results of this study, together with other information such as rivet quality, productivity, tool weight, comfort, worker acceptance, and initial cost can be used to make informed bucking bar selections. PMID:25381185

Laboratory and workplace assessments of rivet bucking bar vibration emissions.

PubMed

McDowell, Thomas W; Warren, Christopher; Xu, Xueyan S; Welcome, Daniel E; Dong, Ren G

2015-04-01

Sheet metal workers operating rivet bucking bars are at risk of developing hand and wrist musculoskeletal disorders associated with exposures to hand-transmitted vibrations and forceful exertions required to operate these hand tools. New bucking bar technologies have been introduced in efforts to reduce workplace vibration exposures to these workers. However, the efficacy of these new bucking bar designs has not been well documented. While there are standardized laboratory-based methodologies for assessing the vibration emissions of many types of powered hand tools, no such standard exists for rivet bucking bars. Therefore, this study included the development of a laboratory-based method for assessing bucking bar vibrations which utilizes a simulated riveting task. With this method, this study evaluated three traditional steel bucking bars, three similarly shaped tungsten alloy bars, and three bars featuring spring-dampeners. For comparison the bucking bar vibrations were also assessed during three typical riveting tasks at a large aircraft maintenance facility. The bucking bars were rank-ordered in terms of unweighted and frequency-weighted acceleration measured at the hand-tool interface. The results suggest that the developed laboratory method is a reasonable technique for ranking bucking bar vibration emissions; the lab-based riveting simulations produced similar rankings to the workplace rankings. However, the laboratory-based acceleration averages were considerably lower than the workplace measurements. These observations suggest that the laboratory test results are acceptable for comparing and screening bucking bars, but the laboratory measurements should not be directly used for assessing the risk of workplace bucking bar vibration exposures. The newer bucking bar technologies exhibited significantly reduced vibrations compared to the traditional steel bars. The results of this study, together with other information such as rivet quality, productivity, tool weight, comfort, worker acceptance, and initial cost can be used to make informed bucking bar selections. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

[Influence of two positions for measuring instrument adapter on measurement of hand-transmitted vibration in grinding machine].

PubMed

Xie, X S; Zhang, M; Zheng, Y D; Du, X Y; Qi, C

2016-06-20

To investigate the influence of two positions for measuring instrument adapter on the measurement of hand-transmitted vibration in grinding machine using the intraclass correlation coefficient (ICC) of reliability assessment index, and to provide a basis for studies on the measurement standard for hand-transmitted vibration. With reference to the measurement standard for hand-transmitted vibration ISO 5349 Mechanical vibration-Measurement and evaluation of human exposure to hand-transmitted vibration-Part 1: General requirements and Mechanical vibration-Measurement and evaluation of human exposure to hand-transmitted vibration-Part 2: Practical guidance for measurement at the workplace, the domestic AWA5936 hand-transmitted vibration measuring instrument and SVAN-106 hand-transmitted vibration measuring instrument from Poland were used to measure hand-transmitted vibration in 3 workers for grinding machine in a foundry for 5 days continuously from September to October, 2014, and Y-axis data were recorded and compared. In worker A, the "T" -shaped adapter had a significantly higher mean Y-axis accelerated speed effective value than the "O" -shaped adapter [4.34 m/s(2) (95%CI 4.05(-)4.63) vs 2.32 m/s(2) (95%CI 2.27~2.38) , t=13.781, P<0.01]. In workers B and C, AWA5936 "U" -shaped adapter (placed at the position of the handle of grinding machine) had lower degrees of data variation of 12.55% and 15.77%, respectively, suggesting good data stability. The measurement results showed significant differences across different positions of adapter (P<0.01) and between all adapters except "O" -shaped and line-shaped adapters (all P<0.01) , while the measurement results showed no significant differences between the "O" -shaped and line-shaped adapters (P>0.01). The comparison of the measurement results of AWA5936 vibration measuring instrument with an "U" -shaped adapter and SVAN-106 vibration measuring instrument with an "S" -shaped adapter showed an ICC of >0.80 (ICC=0.82) , while the comparison of the measurement results of AWA5936 vibration measuring instrument with an "O" -shaped adapter and SVAN-106 vibration measuring instrument showed an ICC of <0.40. SVAN-106 vibration measuring instrument with an "S" -shaped adapter placed at the palm and AWA5936 vibration measuring instrument with an "U" -shaped adapter placed at the handle of grinding machine can give comparable measurement results with good reliability.

[Assessment of energy and macronutrients supply in daily food rations of people exposed to hand transmitted vibrations].

PubMed

Zabłocka-Słowińska, Katarzyna; Limburska, Joanna; Prescha, Anna; Pieczyńska, Joanna; Tomczyk, Jarosław; Grajeta, Halina

2011-01-01

Occupational exposure of workers to mechanical hand transmitted vibrations may result in the development of nonspecific lesions. Balanced diet is one of factors that protect human organism against abnormalities resulting from occupational exposure. The aim of this study was to assess the supply of energy and macronutrients in daily food rations (DFR) of people exposed to hand transmitted vibration. Eighty workers, including 37 men (mean age 44.6 years) and 43 women (mean age 44 years) exposed to hand transmitted vibrations were recruited in this study. Of those, 72 people worked in crystal glassworks as glass cutters, 5 people were physiotherapists and 3 were woodcutters. For all workers, there was measured exposure to hand transmitted vibration. Nutritional status was assessed using 24-hour dietary recall; the procedure was repeated 3 times. The results of the nutritional assessment were compared with recommended daily allowances (RDA) for energy, protein, minerals and vitamins, total carbohydrates, total fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), cholesterol and dietary fibre. The average intake of energy in daily food rations of the women was too low while men received the appropriate amount of energy. Average protein intake by men and women was higher than the relevant RDA. The average amount of carbohydrates received by the surveyed women and men were too low, just as the consumption of PUFA, dietary fibre, potassium and calcium. We also found an excessive, average supply of total fat, MUFA, SFA, cholesterol and most of the vitamins with the DFR of the women and men. The nutrition in the group of workers exposed to hand transmitted vibration was found to be imbalanced due to excessive intakes of total fat, saturated fatty acids and cholesterol combined with insufficient consumption of carbohydrates, dietary fibres, potassium and calcium. The co-occurrence of vibration and imbalanced diet may increase the susceptibility of the subjects to cardiovascular and bone diseases.

HTR1B gene variants associate with the susceptibility of Raynauds' phenomenon in workers exposed hand-arm vibration.

PubMed

Chen, Qingsong; Lang, Li; Xiao, Bin; Lin, Hansheng; Yang, Aichu; Li, Hongling; Tang, Shichuan; Huang, Hanlin

2016-10-05

To explore whether polymorphic variants of the HTR1B gene are associated with the susceptibility of Raynauds' Phenomenon (RP) coursed by vibration. 148 subjects exposed to vibration for more than 2 years were classified into either induced white finger (VWF) group (n = 72), or non-VWF group (n = 76). Vibration exposure levels were measured and assessed following ISO 5349-1:2001 protocol. All workers were genotyped by sequencing for the single nucleotide polymorphisms (SNPs) in the 5'-flanking and coding region of HTR1B. Genetic characteristics and linkage disequilibrium (LD) were analyzed with Haploview. Serum serotonin levels of each subject were detected using ELISA. The association between the susceptibility of vascular damage and genotype was analyzed via logistic regression. 7 known SNPs were obtained and their allele frequencies were inserted into the Hardy-Weinberg equilibrium. rs6297 variant genotype had an increased risk of VWF compared with wild genotype (OR = 2.14, 95% CI = 1.04- 4.58, P < 0.05). rs6298 mutant type (AG+GG) was found to have a significant interaction on vibration exposure LN(CEI), accounting for VWF occurrence. LN(5-HT) level is significantly different between the VWF group (x¯±s= 1.99±1.09 ng/mL) and the non-VWF group (x¯±s= 2.72±1.47 ng/mL). Serotonin levels may affect the progression of secondary RP. Polymorphic variants of the HTR1B gene are associated with the susceptibility of secondary RP in vibration-exposed occupational populations of Chinese Han people.

Fluoroscopic radiation exposure: are we protecting ourselves adequately?

PubMed

Hoffler, C Edward; Ilyas, Asif M

2015-05-06

While traditional intraoperative fluoroscopy protection relies on thyroid shields and aprons, recent data suggest that the surgeon's eyes and hands receive more exposure than previously appreciated. Using a distal radial fracture surgery model, we examined (1) radiation exposure to the eyes, thyroid, chest, groin, and hands of a surgeon mannequin; (2) the degree to which shielding equipment can decrease exposure; and (3) how exposure varies with fluoroscopy unit size. An anthropomorphic model was fit with radiation-attenuating glasses, a thyroid shield, an apron, and gloves. "Exposed" thermoluminescent dosimeters overlaid the protective equipment at the eyes, thyroid, chest, groin, and index finger while "shielded" dosimeters were placed beneath the protective equipment. Fluoroscopy position and settings were standardized. The mini-c-arm milliampere-seconds were fixed based on the selection of the kilovolt peak (kVp). Three mini and three standard c-arms scanned a model of the patient's wrist continuously for fifteen minutes each. Ten dosimeter exposures were recorded for each c-arm. Hand exposure averaged 31 μSv/min (range, 22 to 48 μSv/min), which was 13.0 times higher than the other recorded exposures. Eye exposure averaged 4 μSv/min, 2.2 times higher than the mean thyroid, chest, and groin exposure. Gloves reduced hand exposure by 69.4%. Glasses decreased eye exposure by 65.6%. There was no significant difference in exposure between mini and standard fluoroscopy. Surgeons' hands receive the most radiation exposure during distal radial plate fixation under fluoroscopy. There was a small but insignificant difference in mean exposure between standard fluoroscopy and mini-fluoroscopy, but some standard units resulted in lower exposure than some mini-units. On the basis of these findings, we recommend routine protective equipment to mitigate exposure to surgeons' hands and eyes, in addition to the thyroid, chest, and groin, during fluoroscopy procedures. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Disability in the upper extremity and quality of life in hand-arm vibration syndrome.

PubMed

Poole, Kerry; Mason, Howard

2005-11-30

To investigate whether hand-arm vibration syndrome (HAVS) leads to disability in the upper extremity or deficit in quality of life (QoL) using validated questionnaire tools, and to establish whether these effects are related to the Stockholm Workshop Staging (SWS). This was a postal cross-sectional questionnaire study with a 50% response rate. Four hundred and forty-four males, who had been diagnosed and staged according to the SWS were sent the Disability in the Arm, Shoulder and Hand (DASH) and the SF-36v2 QoL questionnaires. HAVS cases had significantly greater DASH disability scores and reduced QoL physical and mental component scores compared to published normal values. Those HAVS cases with a presumptive diagnosis of Carpal Tunnel Syndrome(CTS) had even higher disability scores. There was a clear, linear relationship between both the DASH disability score and the physical component of the QoL and sensorineural SWS, but not with the vascular SWS. HAVS has a significant effect on an individual's perceived ability to perform everyday tasks involving the upper extremity, and their quality of life. Physical capability may be further compromised in those individuals who have a presumptive diagnosis of CTS. These findings may have important implications regarding management of the affected worker.

Diagnostic criteria and staging of hand-arm vibration syndrome in the United Kingdom.

PubMed

McGeoch, Kenneth L; Lawson, Ian J; Burke, Frank; Proud, George; Miles, Jeremy

2005-07-01

In the United Kingdom the diagnosis of Hand-arm Vibration Syndrome varies depending on the purpose of that diagnosis. The criteria differ in three situations. More than 100,000 miners and ex-miners with claims for HAVS have been examined using a Medical Assessment Process which included the use of standardised tests. This contract is unique but it has had significant effects on the two other processes. The Industrial Injuries Disablement Benefit Scheme provides a benefit that can be paid to an employed earner because of an accident or Prescribed Disease. New recommendations have been published to remove the anomalies in the present format for assessing HAVS. If implemented the new scheme will recognise the Stockholm Workshop Scales and workers with neurological problems will also be compensated. The Health and Safety Executive will issue new guidance in the near future on the hazards of hand-arm vibration. Health surveillance in the workplace will be fundamental and the HSE propose a tiered approach with levels 1 to 5. Specialist occupational nurses and doctors with training in the diagnosis and assessment of HAVS will be needed for levels 3 and 4. Only at this level may a diagnosis of HAVS be made. The Medical Assessment Process has demonstrated that it is possible to examine a large number of claimants in a standardised manner. The IIAC and HSE recommendations contain very important improvements on the existing positions in the UK and it must be hoped that they will be implemented in the near future.

Hand-arm vibration in the aetiology of hearing loss in lumberjacks.

PubMed Central

Pyykkö, I; Starck, J; Färkkilä, M; Hoikkala, M; Korhonen, O; Nurminen, M

1981-01-01

A longitudinal study of hearing loss was conducted among a group of lumberjacks in the years 1972 and 1974--8. The number of subjects increased from 72 in 1972 to 203 in 1978. They were classified according to (1) a history of vibration-induced white finger (VWF), (2) age, (3) duration of exposure, an (4) duration of ear muff usage. The hearing level at 4000 Hz was used to indicate the noise-induced permanent threshold shift (NIPTS). The lumberjacks were exposed, at their present pace of work, to noise, Leq values 96-103 dB(A), and to the vibration of a chain saw (linear acceleration 30-70 ms-2). The chain saws of the early 1960s were more hazardous, with the average noise level of 111 dB(A) and a variation acceleration of 60-180 ms-2. When classified on the basis of age, the lumberjacks with VWF had about a 10 dB greater NIPTS than subjects without VWF. NIPTS increased with the duration of exposure to chain saw noise, but with equal noise exposure the NIPTS was about 10 dB greater in lumberjacks with VWF than without VWF. With the same duration of ear protection the lumberjacks with VWF consistently had about a 10 dB greater NIPTS than those without VWF. The differences in NIPTS were statistically significant. The possible reason for more advanced NIPTS in subjects with VWF is that vibration might operate in both of these disorders through a common mechanism--that is, producing a vasoconstriction in both cochlear and digital blood vessels as a result of sympathetic nervous system activity. PMID:7272242

Digital vibration threshold testing and ergonomic stressors in automobile manufacturing workers: a cross-sectional assessment.

PubMed

Gold, J E; Punnett, L; Cherniack, M; Wegman, D H

2005-01-01

Upper extremity musculoskeletal disorders (UEMSDs) comprise a large proportion of work-related illnesses in the USA. Physical risk factors including manual force and segmental vibration have been associated with UEMSDs. Reduced sensitivity to vibration in the fingertips (a function of nerve integrity) has been found in those exposed to segmental vibration, to hand force, and in office workers. The objective of this study was to determine whether an association exists between digital vibration thresholds (VTs) and exposure to ergonomic stressors in automobile manufacturing. Interviews and physical examinations were conducted in a cross-sectional survey of workers (n = 1174). In multivariable robust regression modelling, associations with workers' estimates of ergonomic stressors stratified on tool use were determined. VTs were separately associated with hand force, vibration as felt through the floor (whole body vibration), and with an index of multiple exposures in both tool users and non-tool users. Additional associations with contact stress and awkward upper extremity postures were found in tool users. Segmental vibration was not associated with VTs. Further epidemiologic and laboratory studies are needed to confirm the associations found. The association with self-reported whole body vibration exposure suggests a possible sympathetic nervous system effect, which remains to be explored.

Health hazard evaluation report HETA 85-039-1723, E. L. Smithe Machine Company, Duncansville, Pennsylvania

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

Bennett, D.E.

1986-08-01

The International Association of Machinists Local 2348 requested an investigation of reported skin rashes and headaches associated with cutting and cooling oils and solvents used in the machine shop. Of 62 employees interviewed, 42 had experienced skin problems occurring on their hands and arms including red skin, dry skin, cracked skin, or itchy skin, related to chemical exposures at the workplace. Xerosis, lichenification, or eczema of the hands and arms were noted on examination of 17 employees of the Lathe Department and 18 of those from the Milling Department. Respiratory and neurological complaints were also found among these employees. Themore » author concluded that the incidence of hand and arm xerosis and eczema in workers in the machining area may be associated with exposure to cutting oils. The author recommends that changes be made to minimize skin exposure and provide adequate ventilation and humidification.« less

Illusory movements induced by tendon vibration in right- and left-handed people.

PubMed

Tidoni, Emmanuele; Fusco, Gabriele; Leonardis, Daniele; Frisoli, Antonio; Bergamasco, Massimo; Aglioti, Salvatore Maria

2015-02-01

Frequency-specific vibratory stimulation of peripheral tendons induces an illusion of limb movement that may be useful for restoring proprioceptive information in people with sensorimotor disability. This potential application may be limited by inter- and intra-subject variability in the susceptibility to such an illusion, which may depend on a variety of factors. To explore the influence of stimulation parameters and participants' handedness on the movement illusion, we vibrated the right and left tendon of the biceps brachii in a group of right- and left-handed people with five stimulation frequencies (from 40 to 120 Hz in step of 20 Hz). We found that all participants reported the expected illusion of elbow extension, especially after 40 and 60 Hz. Left-handers exhibited less variability in reporting the illusion compared to right-handers across the different stimulation frequencies. Moreover, the stimulation of the non-dominant arm elicited a more vivid illusion with faster onset relative to the stimulation of the dominant arm, an effect that was independent from participants' handedness. Overall, our data show that stimulation frequency, handedness and arm dominance influence the tendon vibration movement illusion. The results are discussed in reference to their relevance in linking motor awareness, improving current devices for motor ability recovery after brain or spinal damage and developing prosthetics and virtual embodiment systems.

Dupuytren disease is highly prevalent in male field hockey players aged over 60 years.

PubMed

Broekstra, Dieuwke C; van den Heuvel, Edwin R; Lanting, Rosanne; Harder, Tom; Smits, Inge; Werker, Paul M N

2016-09-22

Dupuytren disease is a fibroproliferative hand condition. The role of exposure to vibration as a risk factor has been studied with contradictory results. Since field hockey is expected to be a strong source of hand-arm vibration, we hypothesised that long-term exposure to field hockey is associated with Dupuytren disease. In this cross-sectional cohort study, the hands of 169 male field hockey players (IQR: 65-71 years) and 156 male controls (IQR: 59-71 years) were examined for signs of Dupuytren disease. Details about their age, lifestyle factors, medical history, employment history and leisure activities were gathered. Prior to the analyses, the groups were balanced in risk factors using propensity score matching. The association between field hockey and Dupuytren disease was determined using a subject-specific generalised linear mixed model with a binomial distribution and logit link function (matched pairs analysis). Dupuytren disease was observed in 51.7% of the field hockey players, and in 13.8% of the controls. After propensity score matching, field hockey playing as dichotomous variable, was associated with Dupuytren disease (OR=9.42, 95% CI 3.01 to 29.53). A linear dose-response effect of field hockey (hours/week x years) within the field hockey players could not be demonstrated (OR=1.03, 95% CI 0.68 to 1.56). We found that field hockey playing has a strong association with the presence of Dupuytren disease. Clinicians in sports medicine should be alert to this less common diagnosis in this sport. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

A critique of a UK standardized test of finger rewarming after cold provocation in the diagnosis and staging of hand-arm vibration syndrome.

PubMed

Mason, H J; Poole, K; Saxton, J

2003-08-01

Accurate diagnosis and staging of hand-arm vibration syndrome (HAVS) is important in health surveillance of vibration-exposed workers and the substantial number of related medico-legal cases. The measurement of the rewarming rate of fingers after cold provocation to the hands (CPT) has been suggested as a useful test in diagnosing HAVS. To investigate the diagnostic value of a standardized version of the CPT test using a 15 degrees C cold challenge for 5 min applied in the recent compensation assessment of UK miners. Analysis of a subset of UK miners assessed at our unit, together with data from a small repeatability study of the standardized CPT in normal subjects. Rewarming time in the CPT was significantly lower in those subjects classified as vascular Stockholm stage 0 compared with Stockholm stages 1-3 combined, but did not discriminate between the stages of abnormality. Using the suggested cut-off in the CPT test, the sensitivity and specificity were calculated as 43 and 78%, respectively. Receiver operator characteristic analysis suggested that the rewarming time of highest accuracy gave a sensitivity of 66% and specificity of 59%. In 10 miners who reported unilateral hand blanching, there was no significant difference in CPT measurements between blanching and non-blanching hands. Repeat CPT measurements in normal subjects suggested mean differences of 52 and 107 s for each hand, and the Bland-Altman coefficient of repeatability was approximately 600 s for all fingers. Single application of this standardized CPT test may have limited value in diagnosing the vascular component of HAVS in an individual.

An examination of an adapter method for measuring the vibration transmitted to the human arms.

PubMed

Xu, Xueyan S; Dong, Ren G; Welcome, Daniel E; Warren, Christopher; McDowell, Thomas W

2015-09-01

The objective of this study is to evaluate an adapter method for measuring the vibration on the human arms. Four instrumented adapters with different weights were used to measure the vibration transmitted to the wrist, forearm, and upper arm of each subject. Each adapter was attached at each location on the subjects using an elastic cloth wrap. Two laser vibrometers were also used to measure the transmitted vibration at each location to evaluate the validity of the adapter method. The apparent mass at the palm of the hand along the forearm direction was also measured to enhance the evaluation. This study found that the adapter and laser-measured transmissibility spectra were comparable with some systematic differences. While increasing the adapter mass reduced the resonant frequency at the measurement location, increasing the tightness of the adapter attachment increased the resonant frequency. However, the use of lightweight (≤15 g) adapters under medium attachment tightness did not change the basic trends of the transmissibility spectrum. The resonant features observed in the transmissibility spectra were also correlated with those observed in the apparent mass spectra. Because the local coordinate systems of the adapters may be significantly misaligned relative to the global coordinates of the vibration test systems, large errors were observed for the adapter-measured transmissibility in some individual orthogonal directions. This study, however, also demonstrated that the misalignment issue can be resolved by either using the total vibration transmissibility or by measuring the misalignment angles to correct the errors. Therefore, the adapter method is acceptable for understanding the basic characteristics of the vibration transmission in the human arms, and the adapter-measured data are acceptable for approximately modeling the system.

An examination of an adapter method for measuring the vibration transmitted to the human arms

PubMed Central

Xu, Xueyan S.; Dong, Ren G.; Welcome, Daniel E.; Warren, Christopher; McDowell, Thomas W.

2016-01-01

The objective of this study is to evaluate an adapter method for measuring the vibration on the human arms. Four instrumented adapters with different weights were used to measure the vibration transmitted to the wrist, forearm, and upper arm of each subject. Each adapter was attached at each location on the subjects using an elastic cloth wrap. Two laser vibrometers were also used to measure the transmitted vibration at each location to evaluate the validity of the adapter method. The apparent mass at the palm of the hand along the forearm direction was also measured to enhance the evaluation. This study found that the adapter and laser-measured transmissibility spectra were comparable with some systematic differences. While increasing the adapter mass reduced the resonant frequency at the measurement location, increasing the tightness of the adapter attachment increased the resonant frequency. However, the use of lightweight (≤15 g) adapters under medium attachment tightness did not change the basic trends of the transmissibility spectrum. The resonant features observed in the transmissibility spectra were also correlated with those observed in the apparent mass spectra. Because the local coordinate systems of the adapters may be significantly misaligned relative to the global coordinates of the vibration test systems, large errors were observed for the adapter-measured transmissibility in some individual orthogonal directions. This study, however, also demonstrated that the misalignment issue can be resolved by either using the total vibration transmissibility or by measuring the misalignment angles to correct the errors. Therefore, the adapter method is acceptable for understanding the basic characteristics of the vibration transmission in the human arms, and the adapter-measured data are acceptable for approximately modeling the system. PMID:26834309

A longitudinal study of vibration white finger, cold response of digital arteries, and measures of daily vibration exposure.

PubMed

Bovenzi, Massimo

2010-03-01

To investigate prospectively the relation between vibration-induced vascular disorders and measures of daily exposure to hand-transmitted vibration (HTV). Two hundred and forty-nine HTV workers and 138 control men of the same companies participated in a 3-year follow-up study. The diagnosis of vibration induced white finger (VWF) in the HTV workers and that of Raynaud's phenomenon in the controls was based on the medical history, the administration of color charts and the results of a cold test with measurement of finger systolic blood pressures. Vibration magnitudes from the tools were measured as r.m.s acceleration, frequency weighted according to international standard ISO 5349-1, and also unweighted over the frequency range 6.3-1,250 Hz. Daily vibration exposure was expressed in terms of daily exposure duration and frequency-weighted or unweighted r.m.s. acceleration normalized to a reference period of 8 h (Aw(8) or Auw(8), respectively). The incidence of VWF varied from 5 to 6% in the HTV workers versus 0-1.5% for Raynaud's phenomenon in the controls. After adjusting for potential confounders, Auw(8) gave better predictions of the incidence of VWF and the cold response of the digital arteries over time than Aw(8) or daily exposure duration. These findings were observed in the entire sample of HTV workers, in those with no VWF at the initial investigation, and in those with normal cold test results at baseline. The findings of this longitudinal study suggest that a measure of daily vibration exposure calculated from unweighted r.m.s. acceleration over the frequency range 6.3-1,250 Hz performs better for the prediction of vascular disorders in users of vibratory tools than a measure derived from r.m.s. acceleration frequency weighted according to ISO 5349-1. This study provides epidemiological evidence that more weight should be given to intermediate and high-frequency vibration for evaluating the severity of hand-transmitted vibration.

Negligent exposures to hand-transmitted vibration.

PubMed

Griffin, Michael J

2008-04-01

If the negligence of an employer results in the disability in an employee, the employer is responsible, in whole or in part, for the disability. The employer is wholly responsible when the worker would not have developed the disability if the employer had taken all reasonable preventative measures. The employer is only partly responsible if the worker would probably have developed some disability even if the employer had taken all reasonable precautions. The employer's responsibility may be estimated from the difference between the actual disability of the worker and the disability that the worker would have suffered if the employer had taken all reasonable preventative measures. This paper considers alternative ways of apportioning negligent and non-negligent exposures to hand-transmitted vibration. The equivalent daily vibration exposure, A(8), used in current EU Directives is shown to be unsuitable for distinguishing between the consequences of negligent and non-negligent exposures because the risks of developing a disorder from hand-transmitted vibration also depend on the years of exposure. Furthermore, daily exposures take no account of individual susceptibility or the practicality of reducing exposure. The consequences of employer negligence may be estimated from the delay in the onset and progression of disorder that would have been achieved if the employer had acted reasonably, such as by reducing vibration magnitude and exposure duration to the minimum that was reasonably achievable in the circumstances. This seems to be fair and reasonable for both employers and employees and indicates the consequences of negligence-the period of the worker's life with disease as a result of negligence and the period for which their employment opportunities may be restricted as a result of the onset of the disorder due to negligence. The effects of negligence may be estimated from the delay in the onset of disease or disability that would have occurred if the employer had behaved reasonably. This definition of negligence encourages employers to reduce risks to the lowest reasonably practical level, consistent with EU Directives.

Muscular forearm activation in hand-grip tasks with superimposition of mechanical vibrations.

PubMed

Fattorini, L; Tirabasso, A; Lunghi, A; Di Giovanni, R; Sacco, F; Marchetti, E

2016-02-01

The purpose of this paper is to evaluate the muscular activation of the forearm, with or without vibration stimuli at different frequencies while performing a grip tasks of 45s at various level of exerted force. In 16 individuals, 9 females and 7 males, the surface electromyogram (EMG) of extensor carpi radialis longus and the flexor carpi ulnari muscles were assessed. At a short latency from onset EMG, RMS and the level of MU synchronization were assessed to evaluate the muscular adaptations. Whilst a trend of decay of EMG Median frequency (MDFd) was employed as an index of muscular fatigue. Muscular tasks consists of the grip of an instrumented handle at a force level of 20%, 30%, 40%, 60% of the maximum voluntary force. Vibration was supplied by a shaker to the hand in mono-frequential waves at 20, 30, 33 and 40Hz. In relation to EMG, RMS and MU synchronization, the muscular activation does not seem to change with the superimposition of the mechanical vibrations, on the contrary a lower MDFd was observed at 33Hz than in absence of vibration. This suggests an early muscular fatigue induced by vibration due to the fact that 33Hz is a resonance frequency for the hand-arm system. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of Frequency-Dependent Responses of the Vascular System to Repetitive Vibration

PubMed Central

Krajnak, Kristine; Miller, G. Roger; Waugh, Stacey; Johnson, Claud; Kashon, Michael L.

2015-01-01

Objective Occupational exposure to hand-transmitted vibration can result in damage to nerves and sensory loss. The goal of this study was to assess the frequency-dependent effects of repeated bouts of vibration on sensory nerve function and associated changes in nerves. Methods The tails of rats were exposed to vibration at 62.5, 125, or 250 Hz (constant acceleration of 49m/s2) for 10 days. The effects on sensory nerve function, nerve morphology, and transcript expression in ventral tail nerves were measured. Results Vibration at all frequencies had effects on nerve function and physiology. However, the effects tended to be more prominent with exposure at 250 Hz. Conclusion Exposure to vibration has detrimental effects on sensory nerve function and physiology. However, many of these changes are more prominent at 250-Hz exposure than at lower frequencies. PMID:22785326

Extracellular signal-regulated kinase activation and endothelin-1 production in human endothelial cells exposed to vibration

PubMed Central

White, Charles R; Haidekker, Mark A; Stevens, Hazel Y; Frangos, John A

2004-01-01

Hand–arm vibration syndrome is a vascular disease of occupational origin and a form of secondary Raynaud's phenomenon. Chronic exposure to hand-held vibrating tools may cause endothelial injury. This study investigates the biomechanical forces involved in the transduction of fluid vibration in the endothelium. Human endothelial cells were exposed to direct vibration and rapid low-volume fluid oscillation. Rapid low-volume fluid oscillation was used to simulate the effects of vibration by generating defined temporal gradients in fluid shear stress across an endothelial monolayer. Extracellular signal-regulated kinase (ERK1/2) phosphorylation and endothelin-1 (ET-1) release were monitored as specific biochemical markers for temporal gradients and endothelial response, respectively. Both vibrational methods were found to phosphorylate ERK1/2 in a similar pattern. At a fixed frequency of fluid oscillation where the duration of each pulse cycle remained constant, ERK1/2 phosphorylation increased with the increasing magnitude of the applied temporal gradient. However, when the frequency of flow oscillation was increased (thus decreasing the duration of each pulse cycle), ERK1/2 phosphorylation was attenuated across all temporal gradient flow profiles. Fluid oscillation significantly stimulated ET-1 release compared to steady flow, and endothelin-1 was also attenuated with the increase in oscillation frequency. Taken together, these results show that both the absolute magnitude of the temporal gradient and the frequency/duration of each pulse cycle play a role in the biomechanical transduction of fluid vibrational forces in endothelial cells. Furthermore, this study reports for the first time a link between the ERK1/2 signal transduction pathway and transmission of vibrational forces in the endothelium. PMID:14724194

Vibration in car repair work.

PubMed

Hansson, J E; Eklund, L; Kihlberg, S; Ostergren, C E

1987-03-01

The main objective of the study was to find efficient hand tools which caused only minor vibration loading. Vibration measurements were carried out under standardised working conditions. The time during which car body repairers in seven companies were exposed to vibration was determined. Chisel hammers, impact wrenches, sanders and saws were the types of tools which generated the highest vibration accelerations. The average daily exposure at the different garages ranged from 22 to 70 min. The risk of vibration injury is currently rated as high. The difference between the highest and lowest levels of vibration was considerable in most tool categories. Therefore the choice of tool has a major impact on the magnitude of vibration exposure. The importance of choosing the right tools and working methods is discussed and a counselling service on vibration is proposed.

Proprioceptive illusions created by vibration of one arm are altered by vibrating the other arm.

PubMed

Hakuta, Naoyuki; Izumizaki, Masahiko; Kigawa, Kazuyoshi; Murai, Norimitsu; Atsumi, Takashi; Homma, Ikuo

2014-07-01

There is some evidence that signals coming from both arms are used to determine the perceived position and movement of one arm. We examined whether the sense of position and movement of one (reference) arm is altered by increases in muscle spindle signals in the other (indicator) arm in blindfolded participants (n = 26). To increase muscle spindle discharge, we applied 70-80 Hz muscle vibration to the elbow flexors of the indicator arm. In a first experiment, proprioceptive illusions in the vibrated reference arm in a forearm position-matching task were compared between conditions in which the indicator arm elbow flexors were vibrated or not vibrated. We found that the vibration illusion of arm extension induced by vibration of reference arm elbow flexors was reduced in the presence of vibration of the indicator elbow flexors. In a second experiment, participants were asked to describe their perception of the illusion of forearm extension movements of the reference arm evoked by vibration of reference arm elbow flexors in response to on/off and off/on transitions of vibration of non-reference arm elbow flexors. When vibration of non-reference arm elbow flexors was turned on, they reported a sensation of slowing down of the illusion of the reference arm. When it was turned off, they reported a sensation of speeding up. To conclude, the present study shows that both the sense of limb position and the sense of limb movement of one arm are dependent to some extent on spindle signals coming from the other arm.

Predicting and controlling risks from human exposures to vibration and mechanical shock: flag waving and flag weaving.

PubMed

Griffin, Michael J

2015-01-01

At work or in leisure activities, many people are exposed to vibration or mechanical shocks associated with risks of injury or disease. This paper identifies information that can be used to decide whether there may be a risk from exposure to hand-transmitted vibration or whole-body vibration and shock, and suggests actions that can control the risks. The complex and time-varying nature of human exposures to vibration and shock, the complexity of the different disorders and uncertainty as to the mechanisms of injury and the factors influencing injury have prevented the definition of dose-response relationships well proven by scientific study. It is necessary to wave a flag indicating when there is a need to control risks from exposure to vibration and shock while scientific enquiry provides understanding needed to weave a better flag. It is concluded that quantifying exposure severity is often neither necessary nor sufficient to either identify risks or implement measures that control the risks. The identification of risks associated with exposure to vibration and mechanical shock cannot, and need not, rely solely on the quantification of exposure severity. Qualitative methods can provide a sufficient indication of the need for control measures, which should not be restricted to reducing standardised measures of exposure severity.

Work-related lesions of the supraspinatus tendon: a case-control study.

PubMed

Seidler, Andreas; Bolm-Audorff, Ulrich; Petereit-Haack, Gabriela; Ball, Elke; Klupp, Magdalena; Krauss, Noëlle; Elsner, Gine

2011-04-01

To examine the dose-response relationship between cumulative duration of work with highly elevated arms (work above shoulder level) as well as of manual material handling and ruptures of the supraspinatus tendon in a population-based case-control study. In 14 radiologic practices, we recruited 483 male patients aged 25-65 with radiographically confirmed partial (n = 385) or total (n = 98) supraspinatus tears associated with shoulder pain. A total of 300 male control subjects were recruited. Data were gathered in a structured personal interview. To calculate cumulative exposure, the self-reported duration of lifting/carrying of heavy loads (>20 kg) as well as the duration of work with highly elevated arms was added up over the entire working life. The results of our study support a dose-response relationship between cumulative duration of work with highly elevated arms and symptomatic supraspinatus tendon tears. For a cumulative duration of >3,195 h work above shoulder level, the risk of a supraspinatus tendon rupture is elevated to 2.0 (95% CI 1.1-3.5), adjusted for age, region, lifting/carrying of heavy loads, handheld vibration, apparatus gymnastics/shot put/javelin/hammer throwing/wrestling, and tennis. The cumulative duration of carrying/lifting of heavy loads also yields a positive dose-response relation with disease (independent from work above shoulder level and from handheld vibration), with an adjusted odds ratio of 1.8 (95% CI 1.0-3.2) in the highest exposure category (>77 h). We find an increased risk for subjects exposed to handheld vibration with an adjusted OR of 3.2 (95% CI 1.7-5.9) in the highest exposure category (16 years or more in the job with exposure), but a clear dose-response relationship is lacking. This study points to a potential etiologic role of long-term cumulative effects of work with highly elevated arms and heavy lifting/carrying on shoulder tendon disorders.

Equal vibrotactile sense thresholds of the fingers and its diagnostic significance for hand-arm vibration syndrome.

PubMed

Cheng, H; Zhang, X C; Duan, L; Ma, Y; Wang, J X

1995-01-01

The vibrotactile sense thresholds (VSTs) of the middle fingers of 60 healthy persons and 97 patients with Hand-Arm Vibration Syndrome (HAVS) or subclinical HAVS were measured quantitatively. Intermittent vibratory irritations were adopted, with vibration stimulus frequencies at 8, 16, 31.5, 63, 125, 250, and 500 Hz. The equal VST contours of the fingers were mapped. Results showed that the VSTs of the normal group were not correlated with sex or handedness. From 8 Hz to 250 Hz the equal VST contours of the normal group were relatively flat; at more than 250 Hz the contours began an abrupt ascent. The VST values had a logarithmic rising tendency with the increasing age of subjects. In the equal VST contours the frequency of the most sensitive threshold value was 125 Hz in the normal group and 8 Hz in the HAVS group. The patients' VST values were higher than that of the healthy persons. The vibrotactilegram showed that the VST values of the patient groups first shifted at high frequencies and VST loss displayed a "V"-type hollow at 125 Hz and 250 Hz. The quantitative test method of VST was a valuable auxiliary detection method for HAVS. The "V"-type hollow of VST was an early clinical manifestation of HAVS.

Weight bearing through lower limbs in a standing frame with and without arm support and low-magnitude whole-body vibration in men and women with complete motor paraplegia.

PubMed

Bernhardt, Kathie A; Beck, Lisa A; Lamb, Jeffry L; Kaufman, Kenton R; Amin, Shreyasee; Wuermser, Lisa-Ann

2012-04-01

The aim of the study was to determine the proportion of body weight borne through the lower limbs in persons with complete motor paraplegia using a standing frame, with and without the support of their arms. We also examined the effect of low-magnitude whole-body vibration on loads borne by the lower limbs. Vertical ground reaction forces (GRFs) were measured in 11 participants (six men and five women) with paraplegia of traumatic origin (injury level T3-T12) standing on a low-magnitude vibrating plate using a standing frame. GRFs were measured in four conditions: (1) no vibration with arms on standing frame tray, (2) no vibration with arms at side, (3) vibration with arms on tray, and (4) vibration with arms at side. GRF with arms on tray, without vibration, was 0.76 ± 0.07 body weight. With arms at the side, GRF increased to 0.85 ± 0.12 body weight. With vibration, mean GRF did not significantly differ from no-vibration conditions for either arm positions. Oscillation of GRF with vibration was significantly different from no-vibration conditions (P < 0.001) but similar in both arm positions. Men and women with paraplegia using a standing frame bear most of their weight through their lower limbs. Supporting their arms on the tray reduces the GRF by approximately 10% body weight. Low-magnitude vibration provided additional oscillation of the load-bearing forces and was proportionally similar regardless of arm position.

Weight Bearing through Lower Limbs in a Standing Frame with and without Arm Support and Low-Magnitude Whole Body Vibration in Men and Women with Complete Motor Paraplegia

PubMed Central

Bernhardt, Kathie A.; Beck, Lisa A.; Lamb, Jeffry L.; Kaufman, Kenton R.; Amin, Shreyasee; Wuermser, Lisa-Ann

2014-01-01

Objective To determine the proportion of body weight (BW) borne through the lower limbs in persons with complete, motor paraplegia using a standing frame, with and without support of their arms. We also examined the effect of low-magnitude whole body vibration on loads borne by the lower extremities. Design Vertical ground reaction forces (GRF) were measured in 11 participants (6 men and 5 women) with paraplegia of traumatic origin (injury level T3 to T12) standing on a low-magnitude vibrating plate using a standing frame. GRF were measured in four conditions: 1) no vibration with arms on standing frame tray; 2) no vibration with arms at side; 3) vibration with arms on tray; 4) vibration with arms at side. Results GRF with arms on tray, without vibration, was 0.76 ± 0.07 BW. With arms at the side, GRF increased to 0.85 ± 0.12 BW. With vibration, mean GRF did not significantly differ from no-vibration conditions for either arm positions. Oscillation of GRF with vibration was significantly different from no-vibration conditions (p<0.001) but similar in both arm positions. Conclusion Men and women with paraplegia using a standing frame bear the majority of their weight through their lower limbs. Supporting their arms on the tray reduces the GRF by ~10% BW. Low-magnitude vibration provided additional oscillation of the load-bearing forces and was proportionally similar regardless of arm position. PMID:22407161

[Field investigation of occupational disease diagnosis in Guangdong Provincial Hospital for Occupational Disease Prevention and Treatment from 2009 to 2014: an analysis of 136 cases].

PubMed

Fan, C Y; Li, X D; Wen, W; Wang, Y Y; Zhang, Y; Lang, L

2016-04-20

To investigate the characteristics of 136 patients with occupational diseases, to summarize key techniques used in field investigation, and to provide a scientific basis for the development of standard operating procedures for field investigation of occupational disease diagnosis. Field investigation and routine data analysis were performed to analyze the cases diagnosed by Guangdong Provincial Hospital for Occupational Disease Prevention and Treatment from January 2009 to December 2014. A total of 136 cases of occupational diseases were diagnosed by Guangdong Provincial Hospital for Occupational Disease Prevention and Treatment from 2009 to 2014, and there were 66 cases of leukemia, 18 cases of suspected occupational benzene poisoning, 12 cases of suspected occupational handarm vibration disease, and 11 cases of suspected pneumoconiosis. Of all these patients, 41.91% were engaged in at least three types of work, 70.59% were exposed to at least three types of chemicals, 25.74% experienced changes in technical processes and chemicals, and 47.06% had disputes on the chemicals they were exposed to during verification by both parties. Occupational hazard factors were detected. Most samples (358)were used to measure benzene concentration in workplace air, among which 11.7% had a benzene concentration of >6.00 mg/m(3)(exceeding standard), 13.41% had a benzene concentration of 3.26~6.00 mg/m(3), 75.42% had a benzene concentration of<0.03 to <3.25 mg/m(3). The samples of suspected occupational hand-arm vibration disease, suspected pneumoconiosis, and suspected occupational noiseinduced hearing loss had high overstandard rates (100%, 93.8%, and 83.3%, respectively). Field investigation of occupational disease diagnosis reveals large numbers of cases of leukemia, suspected occupational benzene poisoning, suspected occupational hand-arm vibration disease, and suspected pneumoconiosis. The key aspects of field investigation include confirmation of the history of occupational exposure, identification of occupational hazard factors, confirmation of the changes in technical processes and chemicals, detection of occupational hazard factors, sampling and analysis of raw materials, and epidemiological investigation of workers with the same type of work.

Hand pain other than carpal tunnel syndrome (CTS): the role of occupational factors.

PubMed

Andréu, José-Luis; Otón, Teresa; Silva-Fernández, Lucía; Sanz, Jesús

2011-02-01

Some occupational factors have been implicated in the development of disorders manifested as hand pain. The associations seem to be well documented in processes such as hand-arm vibration syndrome (HAVS) or writer's cramp. There are contradictory data in the literature about the relationships of trigger finger, De Quervain's tenosynovitis (DQT) and tenosynovitis of the wrist with occupational factors. In this article, we review current knowledge about clinical manifestations, case definition, implicated occupational factors, diagnosis and treatment of the most relevant hand pain disorders that have been associated with occupational factors, excluding carpal tunnel syndrome (CTS). Copyright © 2010 Elsevier Ltd. All rights reserved.

Improved Tennis Racquets Have Tapered Strings

NASA Technical Reports Server (NTRS)

Noever, David A.

1995-01-01

Design concept for better performing tennis racquet. Essence of concept to taper strings in such way as to shift center of percussion (also called "sweet spot") toward the toe (outer end of racquet, farthest from player's hand). In addition to increasing power on serves, also improves player's control and feel of racquet in player's hand. Racquet less likely to twist in player's hand on off-center shots. Important element of better feel is better absorption of vibrations; especially for players having chronic arm problems. String material nylon, animal gut, or other naturally or artifically spun threads. String can be attached to conventional racquet frame.

A prospective cohort study of exposure-response relationship for vibration-induced white finger.

PubMed

Bovenzi, M

2010-01-01

To investigate prospectively the relation between vibration-induced white finger (VWF) and measures of cumulative (lifetime) exposure to hand-transmitted vibration (HTV). Two hundred and forty-nine HTV workers and 138 control men of the same companies participated in a 3-year follow-up study. The diagnosis of VWF (Raynaud's phenomenon in the controls) was based on the medical history, the administration of colour charts and the results of a cold test. Tool vibration magnitudes were expressed as root-mean-square (r.m.s.) acceleration, frequency-weighted according to international standard ISO 5349-1 and also unweighted over the frequency range 6.3-1250 Hz. From the vibration magnitudes and exposure durations, alternative measures of cumulative vibration dose were calculated for each HTV worker, according to the expression: dose = Sigmaa(i)(m)t(i), where a(i) is the acceleration magnitude on tool i, t(i) is the lifetime exposure duration (hours) for tool i, and m = 0, 1, 2 or 4. The incidence of VWF varied from 5 to 6% in the HTV workers versus 0 to 1.5% for Raynaud's phenomenon in the controls. After adjusting for potential confounders, measures of cumulative vibration dose derived from total operating hours and high powers of unweighted acceleration (ie, , with m>1) gave better predictions of the occurrence of VWF than dose measures calculated from frequency-weighted acceleration (ie, ). These findings were observed in the entire sample of HTV workers, in those with no VWF at the initial investigation, and in those with normal cold test results at baseline. This prospective cohort study suggests that measures of cumulative vibration doses constructed from unweighted r.m.s. acceleration perform better for the prediction of VWF than dose measures calculated according to the recommendations of current standards. These findings should contribute to the improvement of the ISO frequency weighting for evaluating the severity of hand-transmitted vibration.

Proprioceptive Interaction between the Two Arms in a Single-Arm Pointing Task.

PubMed

Kigawa, Kazuyoshi; Izumizaki, Masahiko; Tsukada, Setsuro; Hakuta, Naoyuki

2015-01-01

Proprioceptive signals coming from both arms are used to determine the perceived position of one arm in a two-arm matching task. Here, we examined whether the perceived position of one arm is affected by proprioceptive signals from the other arm in a one-arm pointing task in which participants specified the perceived position of an unseen reference arm with an indicator paddle. Both arms were hidden from the participant's view throughout the study. In Experiment 1, with both arms placed in front of the body, the participants received 70-80 Hz vibration to the elbow flexors of the reference arm (= right arm) to induce the illusion of elbow extension. This extension illusion was compared with that when the left arm elbow flexors were vibrated or not. The degree of the vibration-induced extension illusion of the right arm was reduced in the presence of left arm vibration. In Experiment 2, we found that this kinesthetic interaction between the two arms did not occur when the left arm was vibrated in an abducted position. In Experiment 3, the vibration-induced extension illusion of one arm was fully developed when this arm was placed at an abducted position, indicating that the brain receives increased proprioceptive input from a vibrated arm even if the arm was abducted. Our results suggest that proprioceptive interaction between the two arms occurs in a one-arm pointing task when the two arms are aligned with one another. The position sense of one arm measured using a pointer appears to include the influences of incoming information from the other arm when both arms were placed in front of the body and parallel to one another.

Proprioceptive Interaction between the Two Arms in a Single-Arm Pointing Task

PubMed Central

Kigawa, Kazuyoshi; Izumizaki, Masahiko; Tsukada, Setsuro; Hakuta, Naoyuki

2015-01-01

Proprioceptive signals coming from both arms are used to determine the perceived position of one arm in a two-arm matching task. Here, we examined whether the perceived position of one arm is affected by proprioceptive signals from the other arm in a one-arm pointing task in which participants specified the perceived position of an unseen reference arm with an indicator paddle. Both arms were hidden from the participant’s view throughout the study. In Experiment 1, with both arms placed in front of the body, the participants received 70–80 Hz vibration to the elbow flexors of the reference arm (= right arm) to induce the illusion of elbow extension. This extension illusion was compared with that when the left arm elbow flexors were vibrated or not. The degree of the vibration-induced extension illusion of the right arm was reduced in the presence of left arm vibration. In Experiment 2, we found that this kinesthetic interaction between the two arms did not occur when the left arm was vibrated in an abducted position. In Experiment 3, the vibration-induced extension illusion of one arm was fully developed when this arm was placed at an abducted position, indicating that the brain receives increased proprioceptive input from a vibrated arm even if the arm was abducted. Our results suggest that proprioceptive interaction between the two arms occurs in a one-arm pointing task when the two arms are aligned with one another. The position sense of one arm measured using a pointer appears to include the influences of incoming information from the other arm when both arms were placed in front of the body and parallel to one another. PMID:26317518

ANTIVIBRATION GLOVES: EFFECTS ON VASCULAR AND SENSORINEURAL FUNCTION, AN ANIMAL MODEL

PubMed Central

Krajnak, K.; Waugh, S.; Johnson, C.; Miller, R. G.; Welcome, D.; Xu, X.; Warren, C.; Sarkisian, S.; Andrew, M.; Dong, R. G.

2015-01-01

Anti-vibration gloves have been used to block the transmission of vibration from powered hand tools to the user, and to protect users from the negative health consequences associated with exposure to vibration. However, there are conflicting reports as to the efficacy of gloves in protecting workers. The goal of this study was to use a characterized animal model of vibration-induced peripheral vascular and nerve injury to determine whether antivibration materials reduced or inhibited the effects of vibration on these physiological symptoms. Rats were exposed to 4 h of tail vibration at 125 Hz with an acceleration 49 m/s2. The platform was either bare or covered with antivibrating glove material. Rats were tested for tactile sensitivity to applied pressure before and after vibration exposure. One day following the exposure, ventral tail arteries were assessed for sensitivity to vasodilating and vasoconstricting factors and nerves were examined histologically for early indicators of edema and inflammation. Ventral tail artery responses to an α2C-adrenoreceptor agonist were enhanced in arteries from vibration-exposed rats compared to controls, regardless of whether antivibration materials were used or not. Rats exposed to vibration were also less sensitive to pressure after exposure. These findings are consistent with experimental findings in humans suggesting that antivibration gloves may not provide protection against the adverse health consequences of vibration exposure in all conditions. Additional studies need to be done examining newer antivibration materials. PMID:25965192

Association of hand and arm disinfection with asthma control in US nurses.

PubMed

Dumas, Orianne; Varraso, Raphäelle; Boggs, Krislyn M; Descatha, Alexis; Henneberger, Paul K; Quinot, Catherine; Speizer, Frank E; Zock, Jan-Paul; Le Moual, Nicole; Camargo, Carlos A

2018-05-01

To investigate the association between occupational exposure to disinfectants/antiseptics used for hand hygiene and asthma control in nurses. In 2014, we invited female nurses with asthma drawn from the Nurses' Health Study II to complete two supplemental questionnaires on their occupation and asthma (cross-sectional study, response rate: 80%). Among 4055 nurses (mean age: 59 years) with physician-diagnosed asthma and asthma medication use in the past year, we examined asthma control, as defined by the Asthma Control Test (ACT). Nurses were asked about the daily frequency of hand hygiene tasks: 'wash/scrub hands with disinfectants/hand sanitizers' (hand hygiene) and 'wash/scrub arms with disinfecting products' (surrogate of surgical hand/arm antisepsis). Analyses were adjusted for age, race, ethnicity, smoking status and body mass index. Nurses with partly controlled asthma (ACT: 20-24, 50%) and poorly controlled asthma (ACT ≤19, 18%) were compared with nurses with controlled asthma (ACT=25, 32%). In separate models, both hand and arm hygiene were associated with poorly controlled asthma. After mutual adjustment, only arm hygiene was associated with poorly controlled asthma: OR (95% CI) for <1 time/day, 1.38 (1.06 to 1.80); ≥1 time/day, 1.96 (1.52 to 2.51), versus never. We observed a consistent dose-response relationship between frequency of arm hygiene tasks (never to >10 times/day) and poor asthma control. Associations persisted after further adjustment for surfaces/instruments disinfection tasks. Frequency of hand/arm hygiene tasks in nurses was associated with poor asthma control. The results suggest an adverse effect of products used for surgical hand/arm antisepsis. This potential new occupational risk factor for asthma warrants further study. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Noise, impulse noise, and other physical factors: combined effects on hearing.

PubMed

Pekkarinen, J

1995-01-01

In most of the epidemiologic studies conducted during the last 20 years, impulse noise caused increased risk of hearing loss in comparison to continuous noise with the same acoustical energy. The interaction between noise exposure (broadband at 100 dB(A)) and hand-arm vibration (125 Hz at 2 ms-2 acceleration level) has been proven for people having vibration-induced white finger symptoms. This interaction is evidenced as a permanent hearing loss. However, why the interaction is seen only in people with VWF is not known. The mechanisms may be related to individual susceptibility, and hypotheses are given on the role of the autonomous nervous system regulating the peripheral vascular reaction. Whole-body vibration (2-10 Hz, at 10 ms-2 level) seems to increase the TTS when noise (broadband at 90 dB(A)) is present. This effect is more pronounced at higher temperatures. The hypothermia protects hearing against the effects of noise in animal studies. The interaction between noise and temperature decrease seems obvious in animal studies. Exercise has both increased and decreased the TTS during noise exposure. The effects have been successfully explained as the depression of the stapedius reflex. Thus, less protection against noise is provided for the inner ear in exercise conditions. The increase of the blood temperature also has been suggested to increase noise-induced TTS during exercise. Electromagnetic fields have been found to cause acoustical interactions in the inner ear. Animal studies and human studies have given contradictory results on the effects of magnetic coil devices on hearing. The MR imaging devices produce noise levels of 82-93 dB, which is not sufficient to produce the risk of permanent hearing loss when short exposure durations are taken into consideration. More systematic research is needed with accurately defined electromagnetic characteristics to reveal the potential interactions. The interactions seem to exist, but relatively high levels and durations of exposure are needed to produce an observable effect on hearing. More investigations are still needed on the permanent hearing loss in humans caused by simultaneous long-term exposures to interacting environmental factors.

Surgery for subacromial impingement syndrome in relation to occupational exposures, lifestyle factors and diabetes mellitus: a nationwide nested case-control study.

PubMed

Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid; Svendsen, Susanne Wulff

2017-10-01

To estimate the risk of surgery for subacromial impingement syndrome (SIS) in relation to occupational exposures, lifestyle factors and diabetes mellitus. We conducted a case-control study nested in a register-based cohort study of the Danish working population. For each of 3000 first-time cases of surgery for SIS, two age-matched and sex-matched controls were drawn. Cases and controls received a questionnaire on job history and other factors. Job histories were combined with a psychosocial job exposure matrix (JEM) and the updated Shoulder JEM, which provided exposure intensities on measurement scales. Ten-year cumulative exposures to upper arm elevation >90°, repetitive shoulder movements, forceful shoulder exertions and hand-arm vibrations (HAVs) were estimated. We used conditional logistic regression. There were 5396 persons (60%) who answered the questionnaire. For occupational mechanical exposures, the adjusted OR (OR adj ) ranged from 1.9 (95% CI 1.5 to 2.5 for HAVs) to 2.5 (95% CI 1.9 to 3.5 for force) among men and 1.7 (95% CI 1.2 to 2.5 for HAVs) to 2.0 (95% CI 1.3 to 2.9 for force) among women. No statistically significant associations were found for occupational psychosocial factors. Body mass index (BMI) and pack-years of smoking showed OR adj up to 2.0. Diabetes mellitus showed OR adj of 1.5 (95% CI 1.1 to 2.2) for men and 2.2 (95% CI 1.4 to 3.4) for women. Our findings add to the evidence of an increased risk of surgery for SIS in relation to occupational cumulative mechanical exposures, even when an increased risk in relation to BMI, smoking and diabetes mellitus is taken into account. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Human annoyance, acceptability and concern as responses to vibration from the construction of Light Rapid Transit lines in residential environments.

PubMed

Wong-McSweeney, D; Woodcock, J S; Peris, E; Waddington, D C; Moorhouse, A T; Redel-Macías, M D

2016-10-15

The aim of this paper is to investigate the use of different self-reported measures for assessing the human response to environmental vibration from the construction of an urban LRT (Light Rapid Transit) system. The human response to environmental stressors such as vibration and noise is often expressed in terms of exposure-response relationships that describe annoyance as a function of the magnitude of the vibration. These relationships are often the basis of noise and vibration policy and the setting of limit values. This paper examines measures other than annoyance by expressing exposure-response relationships for vibration in terms of self-reported concern about property damage and acceptability. The exposure-response relationships for concern about property damage and for acceptability are then compared with those for annoyance. It is shown that concern about property damage occurs at vibration levels well below those where there is any risk of damage. Earlier research indicated that concern for damage is an important moderator of the annoyance induced. Acceptability, on the other hand, might be influenced by both annoyance and concern, as well as by other considerations. It is concluded that exposure-response relationships expressing acceptability as a function of vibration exposure could usefully complement existing relationships for annoyance in future policy decisions regarding environmental vibration. The results presented in this paper are derived from data collected through a socio-vibration survey (N=321) conducted for the construction of an urban LRT in the United Kingdom. Copyright © 2016. Published by Elsevier B.V.

Reduction of work-related musculoskeletal risk factors following ergonomics education of sewing machine operators.

PubMed

Bulduk, Sıdıka; Bulduk, Emre Özgür; Süren, Tufan

2017-09-01

Work-related musculoskeletal disorders (WMSDs) are a major hazard for sewing machine operators. Ergonomics education is recommended for reducing musculoskeletal disorders at workstations. This study aimed to evaluate the effect of an ergonomics education in reducing the exposure to risk factors for WMSDs among sewing machine operators. In this study of 278 workers, their exposure to the risk of WMSDs was assessed using the quick exposure check scale prior to them attending an ergonomics education programme and then again 3 months after the programme. The scores for risk exposure before the education programme were moderate for back (static) and back (dynamic), high for shoulder/arm and very high for wrist/hand and neck. The results obtained 3 months later were low for back (static) and shoulder/arm, and moderate for back (dynamic), wrist/hand and neck. Based on our results, ergonomics education can reduce the exposure to risk factors for WMSDs in the workplace.

Transmission of vibration through glove materials: effects of contact force.

PubMed

Md Rezali, Khairil Anas; Griffin, Michael J

2018-04-26

This study investigated effects of applied force on the apparent mass of the hand, the dynamic stiffness of glove materials and the transmission of vibration through gloves to the hand. For 10 subjects, 3 glove materials and 3 contact forces, apparent masses and glove transmissibilities were measured at the palm and at a finger at frequencies in the range 5-300 Hz. The dynamic stiffnesses of the materials were also measured. With increasing force, the dynamic stiffnesses of the materials increased, the apparent mass at the palm increased at frequencies greater than the resonance and the apparent mass at the finger increased at low frequencies. The effects of force on transmissibilities therefore differed between materials and depended on vibration frequency, but changes in apparent mass and dynamic stiffness had predictable effects on material transmissibility. Depending on the glove material, the transmission of vibration through a glove can be increased or decreased when increasing the applied force. Practitioner summary: Increasing the contact force (i.e. push force or grip force) can increase or decrease the transmission of vibration through a glove. The vibration transmissibilities of gloves should be assessed with a range of contact forces to understand their likely influence on the exposure of the hand and fingers to vibration.

Mechanical counter pressure on the arm counteracts adverse effects of hypobaric exposures

NASA Technical Reports Server (NTRS)

Tanaka, Kunihiko; Limberg, Ryan; Webb, Paul; Reddig, Mike; Jarvis, Christine W.; Hargens, Alan R.

2003-01-01

INTRODUCTION: Current space suits have limited movement due to gas pressurization during exposure to the vacuum of space. Alternatively, if pressure is applied by an elastic garment vs. pneumatic garment to produce mechanical counter pressure (MCP), several advantages are possible. In this study, we investigate local microcirculatory and other effects produced with and without a prototype MCP glove and sleeve during exposure to varying levels of vacuum. METHODS: The entire arms of eight male volunteers were studied at normal ambient pressure and during 5 min exposures to -50, -100, and -150 mm Hg with and without the MCP glove and sleeve. Pressure distribution, skin microvascular flow, and temperature were measured. RESULTS: The MCP glove and sleeve generated over 200 mm Hg on the middle finger, dorsum of the hand, and the wrist. However, pressure was significantly lower on the forearm and the upper arm. Without the glove and sleeve, only two of eight subjects tolerated -100 mm Hg. Also, no subject tolerated -150 mm Hg. However, subjects tolerated all vacuum pressures wearing the glove and sleeve. Skin microvascular flow and temperature remained within control values with the glove and sleeve at a chamber pressure of -150 mm Hg. DISCUSSION: The MCP glove and sleeve counteracts adverse effects of vacuum exposures due to lower pressure differentials. Pressure levels over the hand and wrist are similar to those of the current U.S. space suit glove and sleeve, but additional development is required to increase MCP over the forearm and upper arm.

Primary tumor sites in relation to ultraviolet radiation exposure and skin visibility correlate with survival in cutaneous melanoma.

PubMed

Gordon, Daniela; Hansson, Johan; Eloranta, Sandra; Gordon, Max; Gillgren, Peter; Smedby, Karin E

2017-10-01

The prognostic value of detailed anatomic site and ultraviolet radiation (UVR) exposure patterns has not been fully determined in cutaneous melanoma. Thus, we reviewed medical records for detailed site in a population-based retrospective Swedish patient cohort diagnosed with primary invasive melanoma 1976-2003 (n = 5,973). We followed the patients from date of diagnosis until death, emigration or December 31 st 2013, and evaluated melanoma-specific survival by subsite in a multivariable regression model adjusting for established prognostic factors. We found that melanoma on chronic UVR exposure sites (face, dorsum of hands; adjusted HR 0.6; CI 0.4-0.7) and moderately intermittent UVR sites (lateral arms, lower legs, dorsum of feet; HR 0.7; CI 0.6-0.8) were associated with a favorable prognosis compared with highly intermittent sites (chest, back, neck, shoulders and thighs). Further, melanoma on poorly visible skin sites upon self-examination (scalp, retroauricular area, back, posterior upper arms and thighs, buttocks, pubic area; HR 1.3; CI 1.1-1.5) had a worse prognosis than those on easily visible sites (face, chest, abdomen, anterior upper arms and thighs, lower arms and legs, dorsum of hands and feet, palms). In conclusion, highly intermittent UVR exposure sites and poor skin visibility presumably correlate with reduced melanoma survival, independent of established tumor characteristics. A limitation of the study was the lack of information on actual individual UVR exposure. © 2017 UICC.

[Vibration disease: hygienic and medical aspects].

PubMed

Rusanova, D V; Kuleshova, M V; Katamanova, E V; Kartapoltseva, N V; Pankov, V A; Lakhman, O L; Kazakova, P V; Kuptsova, N G

The hygienic assessment of working conditions of employees exposed to local vibration established that working conditions for employees ofvibration dangerous occupations at the aircraft plant according to the degree from a health standpoint and hazard are referred to the fourth (dangerous) class of the degree of danger that stipulates stable high levels of the morbidity rate. The leading factor is a local vibration that results in the consistently high levels of occupational morbidity rate. There was shown the efficiency of the use of the pulsed magnetic stimulation in the treatment ofpatients with vibration disease associated with the exposure to local vibration. For the evaluation of the effectiveness of treatment in patients the condition of the central nervous system was determined with the use of computer electroencephalography with the registration of visual and auditory evoked potentials and somatosensory evoked potentials; there was studied the state of the peripheral nerves in arms and legs relying upom electromyographic data; there was performed psychological study. After the performance of pulse magnetic stimulation in patients diagnosed to have the vibration diseases there were observed the improvement in the interaction of cortical-subcortical structures and associative areas of the frontal and temporal lobes of the brain. After treatment there was noted the shortening of the time of the conduction of the afferent wave of the excitation at the level of the cervical spinal cord, subcortical structures and the central conduction time. There was restored previously reduced the speed of the conduction of the impulse via the distal parts of the tibial and median nerve, through the ulnar nerve in the area of the elbow joint. There was noted the rise in the average temperature on the hands; the decline of thresholds of vibration and pain sensitivity; the improvement of indices characterizing of the state of mnestic- attentional and psycho-emotional scope of activity.

Dose-response patterns for vibration-induced white finger

PubMed Central

Griffin, M; Bovenzi, M; Nelson, C

2003-01-01

Aims: To investigate alternative relations between cumulative exposures to hand-transmitted vibration (taking account of vibration magnitude, lifetime exposure duration, and frequency of vibration) and the development of white finger (Raynaud's phenomenon). Methods: Three previous studies have been combined to provide a group of 1557 users of powered vibratory tools in seven occupational subgroups: stone grinders, stone carvers, quarry drillers, dockyard caulkers, dockyard boilermakers, dockyard painters, and forest workers. The estimated total operating duration in hours was thus obtained for each subject, for each tool, and for all tools combined. From the vibration magnitudes and exposure durations, seven alternative measurements of cumulative exposure were calculated for each subject, using expressions of the form: dose = ∑amiti, where ai is the acceleration magnitude on tool i, ti is the lifetime exposure duration for tool i, and m = 0, 1, 2, or 4. Results: For all seven alternative dose measures, an increase in dose was associated with a significant increase in the occurrence of vibration-induced white finger, after adjustment for age and smoking. However, dose measures with high powers of acceleration (m > 1) faired less well than measures in which the weighted or unweighted acceleration, and lifetime exposure duration, were given equal weight (m = 1). Dose determined solely by the lifetime exposure duration (without consideration of the vibration magnitude) gave better predictions than measures with m greater than unity. All measures of dose calculated from the unweighted acceleration gave better predictions than the equivalent dose measures using acceleration frequency-weighted according to current standards. Conclusions: Since the total duration of exposure does not discriminate between exposures accumulated over the day and those accumulated over years, a linear relation between vibration magnitude and exposure duration seems appropriate for predicting the occurrence of vibration-induced white finger. Poorer predictions were obtained when the currently recommended frequency weighting was employed than when accelerations at all frequencies were given equal weight. Findings suggest that improvements are possible to both the frequency weighting and the time dependency used to predict the development of vibration-induced white finger in current standards. PMID:12499452

Relationship Between Psychomotor Efficiency and Sensation Seeking of People Exposed to Noise and Low Frequency Vibration Stimuli

NASA Astrophysics Data System (ADS)

Korchut, Aleksander; Kowalska-Koczwara, Alicja; Romanska – Zapała, Anna; Stypula, Krzysztof

2017-10-01

At the workplace of the machine operator, low frequency whole body and hand- arm vibrations are observed. They occur together with noise. Whole body vibration in the range of 3-25 Hz are detrimental to the human body due to the location of the resonant frequency of large organs of the human body in this range. It can be assumed that for this reason people working every day in such conditions can have reduced working efficiency. The influence of low frequency vibration and noise on the human body leads to both physiological and functional changes. The result of the impact of noise and vibration stimuli depends largely on the specific characteristics of the objects, which include among other personality traits, temperament and emotional factor. The pilot study conducted in the laboratory was attended by 30 young men. The aim of the study was to look for correlations between the need for stimulation of the objects and their psychomotor efficiency in case of vibration exposure and vibration together with noise exposure in variable conditions task. The need for stimulation of the objects as defined in the study is based on theoretical assumptions of one dimensional model of temperament developed by Marvin Zuckerman. This theory defines the need for stimulation as the search for different, new, complex and intense sensations, as well as the willingness to take risks. The aim of research was to verify if from four factors such as: the search for adventure and horror, sensation seeking, disinhibition and susceptibility to boredom, we can choose the ones that in conjunction with varying operating conditions, may significantly determine the efficiency of the task situation. The objects performed the test evaluation of their motor skills which consisted in keeping the cursor controlled by a joystick through the path. The number of exceeds of the cursor beyond the path and its maximum deviation was recorded. The collected data were used to determine the correlation between the working efficiency and the need for stimulation of the objects under the influence of vibroacoustic factors. The analysis of the results allowed to define a set of criteria that make up the arduous working conditions. The obtained results indicate the need for the continuation of the research.

Vocal Dose Measures: Quantifying Accumulated Vibration Exposure in Vocal Fold Tissues

PubMed Central

Titze, Ingo R.; Švec, Jan G.; Popolo, Peter S.

2011-01-01

To measure the exposure to self-induced tissue vibration in speech, three vocal doses were defined and described: distance dose, which accumulates the distance that tissue particles of the vocal folds travel in an oscillatory trajectory; energy dissipation dose, which accumulates the total amount of heat dissipated over a unit volume of vocal fold tissues; and time dose, which accumulates the total phonation time. These doses were compared to a previously used vocal dose measure, the vocal loading index, which accumulates the number of vibration cycles of the vocal folds. Empirical rules for viscosity and vocal fold deformation were used to calculate all the doses from the fundamental frequency (F0) and sound pressure level (SPL) values of speech. Six participants were asked to read in normal, monotone, and exaggerated speech and the doses associated with these vocalizations were calculated. The results showed that large F0 and SPL variations in speech affected the dose measures, suggesting that accumulation of phonation time alone is insufficient. The vibration exposure of the vocal folds in normal speech was related to the industrial limits for hand-transmitted vibration, in which the safe distance dose was derived to be about 500 m. This limit was found rather low for vocalization; it was related to a comparable time dose of about 17 min of continuous vocalization, or about 35 min of continuous reading with normal breathing and unvoiced segments. The voicing pauses in normal speech and dialogue effectively prolong the safe time dose. The derived safety limits for vocalization will likely require refinement based on a more detailed knowledge of the differences in hand and vocal fold tissue morphology and their response to vibrational stress, and on the effect of recovery of the vocal fold tissue during voicing pauses. PMID:12959470

Vocal dose measures: quantifying accumulated vibration exposure in vocal fold tissues.

PubMed

Titze, Ingo R; Svec, Jan G; Popolo, Peter S

2003-08-01

To measure the exposure to self-induced tissue vibration in speech, three vocal doses were defined and described: distance dose, which accumulates the distance that tissue particles of the vocal folds travel in an oscillatory trajectory; energy dissipation dose, which accumulates the total amount of heat dissipated over a unit volume of vocal fold tissues; and time dose, which accumulates the total phonation time. These doses were compared to a previously used vocal dose measure, the vocal loading index, which accumulates the number of vibration cycles of the vocal folds. Empirical rules for viscosity and vocal fold deformation were used to calculate all the doses from the fundamental frequency (F0) and sound pressure level (SPL) values of speech. Six participants were asked to read in normal, monotone, and exaggerated speech and the doses associated with these vocalizations were calculated. The results showed that large F0 and SPL variations in speech affected the dose measures, suggesting that accumulation of phonation time alone is insufficient. The vibration exposure of the vocal folds in normal speech was related to the industrial limits for hand-transmitted vibration, in which the safe distance dose was derived to be about 500 m. This limit was found rather low for vocalization; it was related to a comparable time dose of about 17 min of continuous vocalization, or about 35 min of continuous reading with normal breathing and unvoiced segments. The voicing pauses in normal speech and dialogue effectively prolong the safe time dose. The derived safety limits for vocalization will likely require refinement based on a more detailed knowledge of the differences in hand and vocal fold tissue morphology and their response to vibrational stress, and on the effect of recovery of the vocal fold tissue during voicing pauses.

A Universal Rig for Supporting Large Hammer Drills: Reduced Injury Risk and Improved Productivity

PubMed Central

Rempel, David; Barr, Alan

2015-01-01

Drilling holes into concrete with heavy hammer and rock drills is one of the most physically demanding tasks performed in commercial construction and poses risks for musculoskeletal disorders, noise induced hearing loss, hand arm vibration syndrome and silicosis. The aim of this study was to (1) use a participatory process to develop a rig to support pneumatic rock drills or large electric hammer drills in order to reduce the health risks and (2) evaluate the usability of the rig. Seven prototype rigs for supporting large hammer drills were developed and modified with feedback from commercial contractors and construction workers. The final design was evaluated by laborers and electricians (N=29) who performed their usual concrete drilling with the usual method and the new rig. Subjective regional fatigue was significantly less in the neck, shoulders, hands and arms, and lower back) when using the universal rig compared to the usual manual method. Usability ratings for the rig were significantly better than the usual method on stability, control, drilling, accuracy, and vibration. Drilling time was reduced by approximately 50% with the rig. Commercial construction contractors, laborers and electricians who use large hammer drills for drilling many holes should consider using such a rig to prevent musculoskeletal disorders, fatigue, and silicosis. PMID:26005290

A pilot study of gene expression analysis in workers with hand-arm vibration syndrome.

PubMed

Maeda, Setsuo; Yu, Xiaozhong; Wang, Rui-Sheng; Sakakibara, Hisataka

2008-04-01

The purpose of this pilot study was to examine differences in gene expressions by cDNA microarray analysis of hand-arm vibration syndrome (HAVS) patients. Vein blood samples were collected and total RNA was extracted. All blood samples were obtained in the morning in one visit after a standard light breakfast. We performed microarray analysis with the labeled cDNA prepared by reverse transcription from RNA samples, using the Human CHIP version 1 (DNA Chip Research Inc, Yokohama, Japan). There are 2,976 genes on the chip, and these genes were selected from a cDNA library prepared with human peripheral white blood cells (WBC). Different gene levels between the HAVS patients and controls, and between groups of HAVS with different levels of symptoms, were indicated by the randomized variance model. The most up-regulated genes were analyzed for their possible functions and association with the occurrence of HAVS. From the results of this pilot study, although the results were obtained a limited number of subjects, it would appear that cDNA microarray analysis of HAVS patients has potential as a new objective method of HAVS diagnosis. Further research is needed to examine the gene expression with increased numbers of patients at different stages of HAVS.

Effects of interset whole-body vibration on bench press resistance training in trained and untrained individuals.

PubMed

Timon, Rafael; Collado-Mateo, Daniel; Olcina, Guillermo; Gusi, Narcis

2016-03-01

Previous studies have demonstrated positive effects of acute vibration exercise on concentric strength and power, but few have observed the effects of vibration exposure on resistance training. The aim of this study was to verify the effects of whole body vibration applied to the chest via hands on bench press resistance training in trained and untrained individuals. Nineteen participants (10 recreationally trained bodybuilders and 9 untrained students) performed two randomized sessions of resistance training on separate days. Each strength session consisted of 3 bench press sets with a load of 75% 1RM to failure in each set, with 2 minutes' rest between sets. All subjects performed the same strength training with either, vibration exposure (12 Hz, 4 mm) of 30 seconds immediately before each bench press set or without vibration. Number of total repetitions, kinematic parameters, blood lactate and perceived exertion were analyzed. In the untrained group, vibration exposure caused a significant increase in the mean velocity (from 0.36±0.02 to 0.39±0.03 m/s) and acceleration (from 0.75±0.10 to 0.86±0.09 m/s2), as well as a decrease in perceived effort (from 8±0.57 to 7.35±0.47) in the first bench press set, but no change was observed in the third bench press set. In the recreationally trained bodybuilders, vibration exposure did not cause any improvement on the performance of bench press resistance training. These results suggest that vibration exposure applied just before the bench press exercise could be a good practice to be implemented by untrained individuals in resistance training.

Vibration characteristics of dental high-speed turbines and speed-increasing handpieces.

PubMed

Poole, Ruth L; Lea, Simon C; Dyson, John E; Shortall, Adrian C C; Walmsley, A Damien

2008-07-01

Vibrations of dental handpieces may contribute to symptoms of hand-arm vibration syndrome in dental personnel and iatrogenic enamel cracking in teeth. However, methods for measuring dental handpiece vibrations have previously been limited and information about vibration characteristics is sparse. This preliminary study aimed to use a novel approach to assess the vibrations of unloaded high-speed handpieces in vitro. Maximum vibration displacement amplitudes of five air turbines and two speed-increasing handpieces were recorded whilst they were operated with and without a rotary cutting instrument (RCI) using a scanning laser vibrometer (SLV). RCI rotation speeds, calculated from frequency peaks, were consistent with expected values. ANOVA statistical analysis indicated significant differences in vibrations between handpiece models (p<0.01), although post hoc tests revealed that differences between most individual models were not significant (p>0.11). Operating handpieces with a RCI resulted in greater vibrations than with no RCI (p<0.01). Points on the head of the handpiece showed greater vibration displacement amplitudes than points along the body (p<0.01). Although no single measurement exceeded 4 microm for the handpieces in the current test setup (implying that these vibrations may be unlikely to cause adverse effects), this study has formed the basis for future work which will include handpiece vibration measurements whilst cutting under clinically representative loads.

Exposure to mobile phone electromagnetic field radiation, ringtone and vibration affects anxiety-like behaviour and oxidative stress biomarkers in albino wistar rats.

PubMed

Shehu, Abubakar; Mohammed, Aliyu; Magaji, Rabiu Abdussalam; Muhammad, Mustapha Shehu

2016-04-01

Research on the effects of Mobile phone radio frequency emissions on biological systems has been focused on noise and vibrations as auditory stressors. This study investigated the potential effects of exposure to mobile phone electromagnetic field radiation, ringtone and vibration on anxiety-like behaviour and oxidative stress biomarkers in albino wistar rats. Twenty five male wistar rats were randomly divided into five groups of 5 animals each: group I: exposed to mobile phone in switched off mode (control), group II: exposed to mobile phone in silent mode, group III: exposed to mobile phone in vibration mode, group IV: exposed to mobile phone in ringtone mode, group V: exposed to mobile phone in vibration and ringtone mode. The animals in group II to V were exposed to 10 min call (30 missed calls for 20 s each) per day for 4 weeks. Neurobehavioural studies for assessing anxiety were carried out 24 h after the last exposure and the animals were sacrificed. Brain samples were collected for biochemical evaluation immediately. Results obtained showed a significant decrease (P < 0.05) in open arm duration in all the experimental groups when compared to the control. A significant decrease (P < 0.05) was also observed in catalase activity in group IV and V when compared to the control. In conclusion, the results of the present study indicates that 4 weeks exposure to electromagnetic radiation, vibration, ringtone or both produced a significant effect on anxiety-like behavior and oxidative stress in young wistar rats.

Dupuytren's contracture and occupational exposure to hand-transmitted vibration

PubMed Central

Palmer, Keith T; D'Angelo, Stefania; Syddall, Holly; Griffin, Michael J; Cooper, Cyrus; Coggon, David

2014-01-01

Aims The relation between Dupuytren's contracture and occupational exposure to hand-transmitted vibration (HTV) has frequently been debated. We explored associations in a representative national sample of workers with well-characterised exposure to HTV. Methods We mailed a questionnaire to 21 201 subjects aged 16–64 years, selected at random from the age-sex registers of 34 general practices in Great Britain and to 993 subjects chosen randomly from military pay records, asking about occupational exposure to 39 sources of HTV and about fixed flexion contracture of the little or ring finger. Analysis was restricted to men at work in the previous week. Estimates were made of average daily vibration dose (A(8) root mean squared velocity (rms)) over that week. Associations with Dupuytren's contracture were estimated by Poisson regression, for lifetime exposure to HTV and for exposures in the past week >A(8) of 2.8 ms−2 rms. Estimates of relative risk (prevalence ratio (PR)) were adjusted for age, smoking status, social class and certain manual activities at work. Results In all 4969 eligible male respondents supplied full information on the study variables. These included 72 men with Dupuytren's contracture, 2287 with occupational exposure to HTV and 409 with A(8)>2.8 ms−2 in the past week. PRs for occupational exposure to HTV were elevated 1.5-fold. For men with an A(8)>2.8 ms−2 in the past week, the adjusted PR was 2.85 (95% CI 1.37 to 5.97). Conclusions Our findings suggest that risk of Dupuytren's contracture is more than doubled in men with high levels of weekly exposure to HTV. PMID:24449599

Nonlinear vibration absorption for a flexible arm via a virtual vibration absorber

NASA Astrophysics Data System (ADS)

Bian, Yushu; Gao, Zhihui

2017-07-01

A semi-active vibration absorption method is put forward to attenuate nonlinear vibration of a flexible arm based on the internal resonance. To maintain the 2:1 internal resonance condition and the desirable damping characteristic, a virtual vibration absorber is suggested. It is mathematically equivalent to a vibration absorber but its frequency and damping coefficients can be readily adjusted by simple control algorithms, thereby replacing those hard-to-implement mechanical designs. Through theoretical analyses and numerical simulations, it is proven that the internal resonance can be successfully established for the flexible arm, and the vibrational energy of flexible arm can be transferred to and dissipated by the virtual vibration absorber. Finally, experimental results are presented to validate the theoretical predictions. Since the proposed method absorbs rather than suppresses vibrational energy of the primary system, it is more convenient to reduce strong vibration than conventional active vibration suppression methods based on smart material actuators with limited energy output. Furthermore, since it aims to establish an internal vibrational energy transfer channel from the primary system to the vibration absorber rather than directly respond to external excitations, it is especially applicable for attenuating nonlinear vibration excited by unpredictable excitations.

Assessment of two alternative standardised tests for the vascular component of the hand-arm vibration syndrome (HAVS).

PubMed

Ye, Ying; Griffin, Michael J

2016-10-01

Vibration-induced white finger (VWF) is the vascular component of the hand-arm vibration syndrome (HAVS). Two tests have been standardised so as to assist the diagnosis of VWF: the measurement of finger rewarming times and the measurement of finger systolic blood pressures (FSBPs). This study investigates whether the two tests distinguish between fingers with and without symptoms of whiteness and compares individual results between the two test methods. In 60 men reporting symptoms of the HAVS, the times for their fingers to rewarm by 4°C (after immersion in 15°C water for 5 min) and FSBPs at 30°C, 15°C and 10°C were measured on the same day. There were significant increases in finger rewarming times and significant reductions in FSBPs at both 15°C and 10°C in fingers reported to suffer blanching. The FSBPs had sensitivities and specificities >90%, whereas the finger rewarming test had a sensitivity of 77% and a specificity of 79%. Fingers having longer rewarming times had lower FSBPs at both temperatures. The findings suggest that, when the test conditions are controlled according to the relevant standard, finger rewarming times and FSBPs can provide useful information for the diagnosis of VWF, although FSBPs are more sensitive and more specific. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

An event-based vibration control for a two-link flexible robotic arm: Numerical and experimental observations

NASA Astrophysics Data System (ADS)

Özer, Abdullah; Eren Semercigil, S.

2008-06-01

Flexible robot manipulators have numerous advantages over their rigid counterparts. They have increased payload-to-weight ratio, they run at higher speeds, use less energy and smaller actuators, and they are safer during interaction with their environments. On the other hand, light design combined with external effects result in components which can oscillate with excessive amplitudes. These oscillations cause deviation from the desired path and long idle periods between tasks in order to perform the intended operation safely and accurately. This paper is on an investigation into the effectiveness of a vibration control technique for a two-link flexible robotic arm. Variable stiffness control (VSC) technique is used to control the excessive oscillations. Owing to its dissipative nature, the technique is stable, it is relatively insensitive to significant parameter changes and suitable to be implemented on existing robots. This research considers that the source of the flexibility is either the joints or the links or both. Simulation results of the response of the arm are presented to show the versatility of the proposed control technique. Experiments are performed on a laboratory prototype and the results are presented to test the validity of simulations.

Effects of vibration on occupant driving performance under simulated driving conditions.

PubMed

Azizan, Amzar; Fard, M; Azari, Michael F; Jazar, Reza

2017-04-01

Although much research has been devoted to the characterization of the effects of whole-body vibration on seated occupants' comfort, drowsiness induced by vibration has received less attention to date. There are also little validated measurement methods available to quantify whole body vibration-induced drowsiness. Here, the effects of vibration on drowsiness were investigated. Twenty male volunteers were recruited for this experiment. Drowsiness was measured in a driving simulator, before and after 30-min exposure to vibration. Gaussian random vibration, with 1-15 Hz frequency bandwidth was used for excitation. During the driving session, volunteers were required to obey the speed limit of 100 kph and maintain a steady position on the left-hand lane. A deviation in lane position, steering angle variability, and speed deviation were recorded and analysed. Alternatively, volunteers rated their subjective drowsiness by Karolinska Sleepiness Scale (KSS) scores every 5-min. Following 30-min of exposure to vibration, a significant increase of lane deviation, steering angle variability, and KSS scores were observed in all volunteers suggesting the adverse effects of vibration on human alertness level. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ergonomic stressors and upper extremity disorders in vehicle manufacturing: cross sectional exposure-response trends

PubMed Central

Punnett, L.

1998-01-01

OBJECTIVE: To evaluate the association between upper extremity soft tissue disorders and exposure to preventable ergonomic stressors in vehicle manufacturing operations. METHODS: A cross sectional study was conducted in one vehicle stamping plant and one engine assembly plant. A standardised physical examination of the upper extremities was performed on all subjects. An interviewer administered questionnaire obtained data on demographics, work history, musculoskeletal symptoms, non-occupational covariates, and psycho-physical (relative intensity) ratings of ergonomic stressors. The primary exposure score was computed by summing the responses to the psychophysical exposure items. Multivariate regression analysis was used to model the prevalence of disorders of the shoulders or upper arms, wrists or hands, and all upper extremity regions (each defined both by symptoms and by physical examination plus symptoms) as a function of exposure quartile. RESULTS: A total of 1315 workers (85% of the target population) was examined. The prevalence of symptom disorders was 22% for the wrists or hands and 15% for the shoulders or upper arms; cases defined on the basis of a physical examination were about 80% as frequent. Disorders of the upper extremities, shoulders, and wrists or hands all increased markedly with exposure score, after adjustment for plant, acute injury, sex, body mass index, systemic disease, and seniority. CONCLUSIONS: Musculoskeletal disorders of the upper extremities were strongly associated with exposure to combined ergonomic stressors. The exposure- response trend was very similar for symptom cases and for physical examination cases. It is important to evaluate all dimensions of ergonomic exposure in epidemiological studies, as exposures often occur in combination in actual workplaces.   PMID:9764102

Simulation of aerodynamic noise and vibration noise in hard disk drives

NASA Astrophysics Data System (ADS)

Zhu, Lei; Shen, Sheng-Nan; Li, Hui; Zhang, Guo-Qing; Cui, Fu-Hao

2018-05-01

Internal flow field characteristics of HDDs are usually influenced by the arm swing during seek operations. This, in turn, can affect aerodynamic noise and airflow-induced noise. In this paper, the dynamic mesh method is used to calculate the flow-induced vibration (FIV) by transient structure analysis and the boundary element method (BEM) is utilized to predict the vibration noise. Two operational states are considered: the arm is fixed and swinging over the disk. Both aerodynamic noise and vibration noise inside drives increase rapidly with increase in disk rotation and arm swing velocities. The largest aerodynamic noise source is always located near the arm and swung with the arm.

Bruising Hands and Arms

MedlinePlus

... due to the weakened state of blood vessel walls from many years of sun exposure. Blood thinners, ... Spring Current Concepts in Dermatology 2902 North Baltimore Street | P.O. Box 7525 | Kirksville, Missouri 63501 660- ...

The diagnostic value of finger systolic blood pressure and cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance.

PubMed

Poole, K; Elms, J; Mason, H J

2004-12-01

Hand-arm vibration syndrome (HAVS) is a complex condition with vascular, sensorineural and musculoskeletal components. A number of quantitative tests have been used for assisting in the diagnosis of HAVS and grading disease severity. To investigate and compare the diagnostic value of finger systolic blood pressure (FSBP) and rewarming of finger skin temperature (FST) following cold-provocation testing, in the assessment of vascular HAVS. Twenty-four individuals with vascular HAVS (Stockholm Workshop stage 2 or 3V) and 22 control subjects underwent FSBP measurements at 30, 15 and 10 degrees C and monitoring of FST following immersion of the hands in water at 15 degrees C for 5 min. There was a significant reduction in median FSBP% in the vascular HAVS group in the change in FSBP from 30 to 15 degrees C adjusted for brachial blood pressure (FSBPC%). There was no difference in the median time for FST to rewarm by 4 degrees C between HAVS cases and controls. The sensitivity and specificity of FSBP to discriminate between the groups varied between 44 and 61% and 91 and 95%, respectively. The sensitivity and specificity for the time for FST to rewarm by 4 degrees C were 71 and 77%. There is little evidence that the described form of finger rewarming after cold-provocation testing is a useful diagnostic test for vascular HAVS, although it may have some moderate influence in ruling out vascular problems. Based on our data, the FSBP may also have limited use in confirming a positive diagnosis of vibration-induced vascular problems. The higher specificity of the FSBP test suggests it may have some value in ruling out the vascular component of HAVS. The data from this study do not confirm the diagnostic power of FSBP for the vascular component of HAVS reported by a few other investigators.

Thermodynamic processes associated with frostbite in the handling of liquid nitrogen

NASA Astrophysics Data System (ADS)

Johnson, W. L.; Cook, C. R.

2014-01-01

It is often taught that exposure to liquid nitrogen will cause frostbite or more severe damage to exposed skin tissue. However, it is also demonstrated that a full hand can be briefly immersed in liquid nitrogen without damage. To better understand and possibly visualize the effects of human tissue exposure to liquid nitrogen, a series of tests were conducted using simulated hands and arms composed of molded gelatin forms. The simulated hands and arms were immersed, sprayed, or splashed with liquid nitrogen both with and without state of the art personal protective equipment. Thermocouples were located within the test articles to allow for thermal mapping during the freezing process. The study is aimed to help understand frostbite hazards and the time constants involved with the handling of liquid nitrogen to improve future safety protocols for the safe handling of cryogenic fluids. Results of the testing also show the limits to handling liquid nitrogen while using various means of protection.

Analysis of WBV on standing and seated passengers during off-peak operation in KL monorail

NASA Astrophysics Data System (ADS)

Hasnan, K.; Bakhsh, Q.; Ahmed, A.; Ali, D.; Jamali, A. R.

2018-03-01

In this study, the Whole-Body Vibration (WBV) was analyzed on the standing and seated passenger during off-peak operating hours when train was on the track. The experiments were conducted on two car train at one constant location (bogie-1, which is near to driver’s cabin) during downward direction from KL sentral station towards Titiwangsa station. The aim of this study was to analyze that, in which posture of passenger’s exposures the maximum level of WBV. Since, one passenger was performed the whole journey in standing posture whereas, the other passenger was in seated posture. The result obtained from experiments for the RMS accelerations (Arms), maximum acceleration (Amax) and minimum acceleration (Amin) during the trip. As per standard ISO 2631-1, the daily vibration exposure (A8), Vibration Dose value (VDV) and Crest Factor (CF) of this trip for both standing and sitting orientations were calculated. Results shows that the seated passenger was exposed to longer periods of continuous vibration as compared to the standing passenger. Whereas, the Vibration Dose value (VDV) value was greater than the action value as per ISO 2631-1 and within the limit values. The study concluded that whole body vibration transmitted towards both passengers either standing or seated during their journey. But in overall results comparison of both orientations, the seated passengers gained higher vibration than the standing one.

Sensorimotor adaptation of point-to-point arm movements after spaceflight: the role of internal representation of gravity force in trajectory planning.

PubMed

Gaveau, Jérémie; Paizis, Christos; Berret, Bastien; Pozzo, Thierry; Papaxanthis, Charalambos

2011-08-01

After an exposure to weightlessness, the central nervous system operates under new dynamic and sensory contexts. To find optimal solutions for rapid adaptation, cosmonauts have to decide whether parameters from the world or their body have changed and to estimate their properties. Here, we investigated sensorimotor adaptation after a spaceflight of 10 days. Five cosmonauts performed forward point-to-point arm movements in the sagittal plane 40 days before and 24 and 72 h after the spaceflight. We found that, whereas the shape of hand velocity profiles remained unaffected after the spaceflight, hand path curvature significantly increased 1 day after landing and returned to the preflight level on the third day. Control experiments, carried out by 10 subjects under normal gravity conditions, showed that loading the arm with varying loads (from 0.3 to 1.350 kg) did not affect path curvature. Therefore, changes in path curvature after spaceflight cannot be the outcome of a control process based on the subjective feeling that arm inertia was increased. By performing optimal control simulations, we found that arm kinematics after exposure to microgravity corresponded to a planning process that overestimated the gravity level and optimized movements in a hypergravity environment (∼1.4 g). With time and practice, the sensorimotor system was recalibrated to Earth's gravity conditions, and cosmonauts progressively generated accurate estimations of the body state, gravity level, and sensory consequences of the motor commands (72 h). These observations provide novel insights into how the central nervous system evaluates body (inertia) and environmental (gravity) states during sensorimotor adaptation of point-to-point arm movements after an exposure to weightlessness.

Feedback control of vibrations in a moving flexible robot arm with rotary and prismatic joints

NASA Technical Reports Server (NTRS)

Wang, P. K. C.; Wei, Jin-Duo

1987-01-01

A robot with a long extendible flexible arm which can also undergo both vertical translation and rotary motion is considered. First, A distributed-parameter model for the robot arm dynamics is developed. It is found that the extending motion could enhance the arm vibrations. Then, a Galerkin-type approximation based on an appropriate time-dependent basis for the solution space is used to obtain an approximate finite-dimensional model for simulation studies. A feedback control for damping the motion-induced vibrations is derived by considering the time rate-of-change of the total vibrational energy of the flexible arm. The authors conclude with some simulation results for a special case with the proposed control law.

Three Case Reports of Successful Vibration Therapy of the Plantar Fascia for Spasticity Due to Cerebral Palsy-Like Syndrome, Fetal-Type Minamata Disease.

PubMed

Usuki, Fusako; Tohyama, Satsuki

2016-04-01

Fetal-type Minamata disease is caused by the exposure to high concentrations of methylmercury in the fetal period and shows cerebral palsy-like clinical features. Relief of spasticity is a major task of rehabilitation to improve their activities of daily living. Here we report the effect of long-term vibration therapy on bilateral lower-limb spasticity in 3 patients with fetal-type Minamata disease. We used a simple, inexpensive, and noninvasive approach with hand-held vibration massagers, which were applied to the plantar fascia at 90 Hz for 15 minutes. The effect was observed soon after the first treatment and resulted in better performance of the repetitive facilitation. Vibration therapy for 1 year improved Modified Ashworth Scale for the ankle flexors in 2 cases. The labored gait improved and gait speed increased in another case. Continued vibration therapy for another 1 year further improved Modified Ashworth Scale score and range of motion of ankle dorsiflexion in 1 case. This case showed the decreased amplitude of soleus H-reflex after the 15-minute vibration therapy, suggesting that α-motor neuron excitability was suppressed. Vibration therapy using a hand-held vibration massager may offer safe and effective treatment for lower-limb spasticity in patients with chronic neurological disorders.

Upper-limb tremor suppression with a 7DOF exoskeleton power-assist robot.

PubMed

Kiguchi, Kazuo; Hayashi, Yoshiaki

2013-01-01

A tremor which is one of the involuntary motions is somewhat rhythmic motion that may occur in various body parts. Although there are several kinds of the tremor, an essential tremor is the most common tremor disorder of the arm. The essential tremor is a disorder of unknown cause, and it is common in the elderly. The essential tremor interferes with a patient's daily living activity, because it may occur during a voluntary motion. If a patient of an essential tremor uses an EMG-based controlled power-assist robot, the robot might misunderstand the user's motion intention because of the effect of the essential tremor. In that case, upper-limb power-assist robots must carry out tremor suppression as well as power-assist, since a person performs various precise tasks with certain tools by the upper-limb in daily living. Therefore, it is important to suppress the tremor at the hand and grasped tool. However, in the case of the tremor suppression control method which suppressed the vibrations of the hand and the tip of the tool, vibration of other part such as elbow might occur. In this paper, the tremor suppression control method for upper-limb power-assist robot is proposed. In the proposed method, the vibration of the elbow is suppressed in addition to the hand and the tip of the tool. The validity of the proposed method was verified by the experiments.

Ulnar neuropathy and ulnar neuropathy-like symptoms in relation to biomechanical exposures assessed by a job exposure matrix: a triple case-referent study.

PubMed

Svendsen, Susanne Wulff; Johnsen, Birger; Fuglsang-Frederiksen, Anders; Frost, Poul

2012-11-01

We aimed to evaluate relations between occupational biomechanical exposures and (1) ulnar neuropathy confirmed by electroneurography (ENG) and (2) ulnar neuropathy-like symptoms with normal ENG. In this triple case-referent study, we identified all patients aged 18-65 years, examined with ENG at a neurophysiological department on suspicion of ulnar neuropathy, 2001-2007. We mailed a questionnaire to 546 patients with ulnar neuropathy, 633 patients with ulnar neuropathy-like symptoms and two separate groups of community referents, matched on sex, age and primary care centre (risk set sampling). The two patient groups were also compared to each other directly. We constructed a Job Exposure Matrix to provide estimates of exposure to non-neutral postures, repetitive movements, hand-arm vibrations and forceful work. Conditional and unconditional logistic regressions were used. The proportion who responded was 59%. Ulnar neuropathy was related to forceful work with an exposure-response pattern reaching an OR of 3.85 (95% CI 2.04 to 7.24); non-neutral postures strengthened effects of forceful work. No relation was observed with repetitive movements. Ulnar neuropathy-like symptoms were related to repetitive movements with an OR of 1.89 (95% CI 1.01 to 3.52) in the highest-exposure category (≥2.5 h/day); forceful work was unrelated to the outcome. Ulnar neuropathy and ulnar neuropathy-like symptoms differed with respect to associations with occupational biomechanical exposures. Findings suggested specific effects of forceful work on the ulnar nerve. Thus, results corroborated the importance of an electrophysiological diagnosis when evaluating risk factors for ulnar neuropathy. Preventive effects may be achieved by reducing biomechanical exposures at work.

Effects of waterproof covering on hand immersion tests using water at 10 degrees C, 12 degrees C and 15 degrees C for diagnosis of hand-arm vibration syndrome.

PubMed

Suizu, K; Harada, N

2005-05-01

To compare effects of waterproof covering on finger skin temperature (FST) and subjective hand pain during immersion tests using cold water at 10 degrees C, 12 degrees C and 15 degrees C. In the (Draft International Standard) of the International Organization for Standardization (ISO/DIS 14835-1), a water temperature of 12 degrees C and use of water covering are proposed. Six healthy male subjects took part in the immersion tests and immersed both hands into water at 10 degrees C, 12 degrees C and 15 degrees C for 5 min, repeatedly, with waterproof covering (polyethylene gloves) or without (bare hands). The FST data from middle fingers and subjective pain scores for hand pain were analyzed. Furthermore, the test with water at 12 degrees C was repeated to assess the repeatability of the test. The glove and water temperature factors for FST were significant at every minute from 1 min during immersion up to 2 min after recovery, showing higher values for waterproof covering than for bare hands and showing lowest values for water temperature of 10 degrees C and highest for 15 degrees C. The glove and water temperature factors for subjective pain score were significant at the 1-min and 2-min points during immersion, showing lower scores for waterproof covering than for bare hands and showing highest scores for water temperature of 10 degrees C and lowest for 15 degrees C. The results of the first and second tests using water of 12 degrees C showed no systematic difference in FST and hand pain between the tests, with a few exceptions. Subjective pain during the cold immersion test with polyethylene gloves and water at 12 degrees C can be reduced, while the differences in FST between water temperatures of 10 degrees C and 12 degrees C were small or not apparent at some points during immersion and recovery. The test also seems to be suitable for repeatability. Further investigation on hand-arm vibration syndrome (HAVS) patients to validate the use of the immersion test with gloves to obtain sufficient data for diagnostic value is required.

The effects of repetitive vibration on sensorineural function: biomarkers of sensorineural injury in an animal model of metabolic syndrome

PubMed Central

Kiedrowski, Megan; Waugh, Stacey; Miller, Roger; Johnson, Claud; Krajnak, Kristine

2016-01-01

Exposure to hand-transmitted vibration in the work-place can result in the loss of sensation and pain in workers. These effects may be exacerbated by pre-existing conditions such as diabetes or the presence of primary Raynaud's phenomena. The goal of these studies was to use an established model of vibration-induced injury in Zucker rats. Lean Zucker rats have a normal metabolic profile, while obese Zucker rats display symptoms of metabolic disorder or Type II diabetes. This study examined the effects of vibration in obese and lean rats. Zucker rats were exposed to 4 h of vibration for 10 consecutive days at a frequency of 125 Hz and acceleration of 49 m/s2 for 10 consecutive days. Sensory function was checked using transcutaneous electrical stimulation on days 1, 5 and 9 of the exposure. Once the study was complete the ventral tail nerves, dorsal root ganglia and spinal cord were dissected, and levels of various transcripts involved in sensorineural dysfunction were measured. Sensorineural dysfunction was assessed using transcutaneous electrical stimulation. Obese Zucker rats displayed very few changes in sensorineural function. However they did display significant changes in transcript levels for factors involved in synapse formation, peripheral nerve remodeling, and inflammation. The changes in transcript levels suggested that obese Zucker rats had some level of sensory nerve injury prior to exposure, and that exposure to vibration activated pathways involved in injury and re-innervation. PMID:26433044

Full-scale investigation of wind-induced vibrations of mast-arm traffic signal structures.

DOT National Transportation Integrated Search

2014-08-01

Because of their inherent : fl : exibility and low damping ratios, cantilevered mast : - : arm : tra : ffi : c signal structures are suscepti : b : le to : wind : - : induced vibrations. : These vibrations : cause stru : ctural stresses and strains t...

Linear modeling of human hand-arm dynamics relevant to right-angle torque tool interaction.

PubMed

Ay, Haluk; Sommerich, Carolyn M; Luscher, Anthony F

2013-10-01

A new protocol was evaluated for identification of stiffness, mass, and damping parameters employing a linear model for human hand-arm dynamics relevant to right-angle torque tool use. Powered torque tools are widely used to tighten fasteners in manufacturing industries. While these tools increase accuracy and efficiency of tightening processes, operators are repetitively exposed to impulsive forces, posing risk of upper extremity musculoskeletal injury. A novel testing apparatus was developed that closely mimics biomechanical exposure in torque tool operation. Forty experienced torque tool operators were tested with the apparatus to determine model parameters and validate the protocol for physical capacity assessment. A second-order hand-arm model with parameters extracted in the time domain met model accuracy criterion of 5% for time-to-peak displacement error in 93% of trials (vs. 75% for frequency domain). Average time-to-peak handle displacement and relative peak handle force errors were 0.69 ms and 0.21%, respectively. Model parameters were significantly affected by gender and working posture. Protocol and numerical calculation procedures provide an alternative method for assessing mechanical parameters relevant to right-angle torque tool use. The protocol more closely resembles tool use, and calculation procedures demonstrate better performance of parameter extraction using time domain system identification methods versus frequency domain. Potential future applications include parameter identification for in situ torque tool operation and equipment development for human hand-arm dynamics simulation under impulsive forces that could be used for assessing torque tools based on factors relevant to operator health (handle dynamics and hand-arm reaction force).

Three Case Reports of Successful Vibration Therapy of the Plantar Fascia for Spasticity Due to Cerebral Palsy-Like Syndrome, Fetal-Type Minamata Disease

PubMed Central

Usuki, Fusako; Tohyama, Satsuki

2016-01-01

Abstract Fetal-type Minamata disease is caused by the exposure to high concentrations of methylmercury in the fetal period and shows cerebral palsy-like clinical features. Relief of spasticity is a major task of rehabilitation to improve their activities of daily living. Here we report the effect of long-term vibration therapy on bilateral lower-limb spasticity in 3 patients with fetal-type Minamata disease. We used a simple, inexpensive, and noninvasive approach with hand-held vibration massagers, which were applied to the plantar fascia at 90 Hz for 15 minutes. The effect was observed soon after the first treatment and resulted in better performance of the repetitive facilitation. Vibration therapy for 1 year improved Modified Ashworth Scale for the ankle flexors in 2 cases. The labored gait improved and gait speed increased in another case. Continued vibration therapy for another 1 year further improved Modified Ashworth Scale score and range of motion of ankle dorsiflexion in 1 case. This case showed the decreased amplitude of soleus H-reflex after the 15-minute vibration therapy, suggesting that α-motor neuron excitability was suppressed. Vibration therapy using a hand-held vibration massager may offer safe and effective treatment for lower-limb spasticity in patients with chronic neurological disorders. PMID:27082608

Vibrations in a moving flexible robot arm

NASA Technical Reports Server (NTRS)

Wang, P. K. C.; Wei, Jin-Duo

1987-01-01

The vibration in a flexible robot arm modeled by a moving slender prismatic beam is considered. It is found that the extending and contracting motions have destabilizing and stabilizing effects on the vibratory motions, respectively. The vibration analysis is based on a Galerkin approximation with time-dependent basis functions. Typical numerical results are presented to illustrate the qualitative features of vibrations.

Evaluation of inertial devices for the control of large, flexible, space-based telerobotic arms

NASA Technical Reports Server (NTRS)

Montgomery, Raymond C.; Kenny, Sean P.; Ghosh, Dave; Shenhar, Joram

1993-01-01

Inertial devices, including sensors and actuators, offer the potential of improving the tracking of telerobotic commands for space-based robots by smoothing payload motions and suppressing vibrations. In this paper, inertial actuators (specifically, torque-wheels and reaction-masses) are studied for that potential application. Batch simulation studies are presented which show that torque-wheels can reduce the overshoot in abrupt stop commands by 82 percent for a two-link arm. For man-in-the-loop evaluation, a real-time simulator has been developed which samples a hand-controller, solves the nonlinear equations of motion, and graphically displays the resulting motion on a computer workstation. Currently, two manipulator models, a two-link, rigid arm and a single-link, flexible arm, have been studied. Results are presented which show that, for a single-link arm, a reaction-mass/torque-wheel combination at the payload end can yield a settling time of 3 s for disturbances in the first flexible mode as opposed to 10 s using only a hub motor. A hardware apparatus, which consists of a single-link, highly flexible arm with a hub motor and a torque-wheel, has been assembled to evaluate the concept and is described herein.

Evaluation of inertial devices for the control of large, flexible, space-based telerobotic arms

NASA Astrophysics Data System (ADS)

Montgomery, Raymond C.; Kenny, Sean P.; Ghosh, Dave; Shenhar, Joram

1993-02-01

Inertial devices, including sensors and actuators, offer the potential of improving the tracking of telerobotic commands for space-based robots by smoothing payload motions and suppressing vibrations. In this paper, inertial actuators (specifically, torque-wheels and reaction-masses) are studied for that potential application. Batch simulation studies are presented which show that torque-wheels can reduce the overshoot in abrupt stop commands by 82 percent for a two-link arm. For man-in-the-loop evaluation, a real-time simulator has been developed which samples a hand-controller, solves the nonlinear equations of motion, and graphically displays the resulting motion on a computer workstation. Currently, two manipulator models, a two-link, rigid arm and a single-link, flexible arm, have been studied. Results are presented which show that, for a single-link arm, a reaction-mass/torque-wheel combination at the payload end can yield a settling time of 3 s for disturbances in the first flexible mode as opposed to 10 s using only a hub motor. A hardware apparatus, which consists of a single-link, highly flexible arm with a hub motor and a torque-wheel, has been assembled to evaluate the concept and is described herein.

Vibration induced white-feet: overview and field study of vibration exposure and reported symptoms in workers.

PubMed

Eger, Tammy; Thompson, Aaron; Leduc, Mallorie; Krajnak, Kristine; Goggins, Katie; Godwin, Alison; House, Ron

2014-01-01

Workers who stand on platforms or equipment that vibrate are exposed to foot-transmitted vibration (FTV). Exposure to FTV can lead to vibration white feet/toes resulting in blanching of the toes, and tingling and numbness in the feet and toes. The objectives are 1) to review the current state of knowledge of the health risks associated with foot-transmitted vibration (FTV), and 2) to identify the characteristics of FTV and discuss the associated risk of vibration-induced injury. Workers who operated locomotives (n=3), bolting platforms (n=10), jumbo drills (n=7), raise drilling platforms (n=4), and crushers (n=3), participated. A tri-axial accelerometer was used to measure FTV in accordance with ISO 2631-1 guidelines. Frequency-weighted root-mean-square acceleration and the dominant frequency are reported. Participants were also asked to report pain/ache/discomfort in the hands and/or feet. Reports of pain/discomfort/ache were highest in raise platform workers and jumbo drill operators who were exposed to FTV in the 40 Hz and 28 Hz range respectively. Reports of discomfort/ache/pain were lowest in the locomotive and crusher operators who were exposed to FTV below 10 Hz. These findings are consistent with animal studies that have shown vascular and neural damage in exposed appendages occurs at frequencies above 40 Hz. Operators exposed to FTV at 40 Hz appear to be at greater risk of experiencing vibration induced injury. Future research is required to document the characteristics of FTV and epidemiological evidence is required to link exposure with injury.

Cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance.

PubMed

Poole, Kerry; Elms, Joanne; Mason, Howard

2006-10-01

The aim was to investigate whether the use of infra-red thermography (I-R) and measurement of temperature gradients along the finger could improve the diagnostic accuracy of cold-provocation testing (15 degrees C for 5 min) in vascular hand-arm vibration syndrome (HAVS). Twenty-one controls and 33 individuals with stages 2/3V HAVS were studied. The standard measurement of time to rewarm by 4 degrees C (T4 degrees C) and temperature gradients between the finger tip, base and middle (measured using I-R) were calculated. Receiver Operating Characteristics (ROC) analysis to distinguish between the two groups revealed that for T4 degrees C the area under the ROC curve was not statistically significantly different from 0.5 (0.64 95% confidence interval 0.49-0.76). The difference between the tip and middle portion of the finger during the sixth minute of recovery was the most promising gradient with an area of 0.76 (95% confidence interval 0.62-0.87), and sensitivity and specificity of 57.6% and 85.7% respectively. However, this was not significantly different from that for the time to rewarm by 4 degrees C. In conclusion, the cold-provocation test used in this study does not appear to discriminate between individuals with stage 2/3V HAVS and controls and this is not improved by the measurement of temperature gradients along the fingers using I-R.

Laboratory and field measurements and evaluations of vibration at the handles of riveting hammers

PubMed Central

McDOWELL, THOMAS W.; WARREN, CHRISTOPHER; WELCOME, DANIEL E.; DONG, REN G.

2015-01-01

The use of riveting hammers can expose workers to harmful levels of hand-transmitted vibration (HTV). As a part of efforts to reduce HTV exposures through tool selection, the primary objective of this study was to evaluate the applicability of a standardized laboratory-based riveting hammer assessment protocol for screening riveting hammers. The second objective was to characterize the vibration emissions of reduced vibration riveting hammers and to make approximations of the HTV exposures of workers operating these tools in actual work tasks. Eight pneumatic riveting hammers were selected for the study. They were first assessed in a laboratory using the standardized method for measuring vibration emissions at the tool handle. The tools were then further assessed under actual working conditions during three aircraft sheet metal riveting tasks. Although the average vibration magnitudes of the riveting hammers measured in the laboratory test were considerably different from those measured in the field study, the rank orders of the tools determined via these tests were fairly consistent, especially for the lower vibration tools. This study identified four tools that consistently exhibited lower frequency-weighted and unweighted accelerations in both the laboratory and workplace evaluations. These observations suggest that the standardized riveting hammer test is acceptable for identifying tools that could be expected to exhibit lower vibrations in workplace environments. However, the large differences between the accelerations measured in the laboratory and field suggest that the standardized laboratory-based tool assessment is not suitable for estimating workplace riveting hammer HTV exposures. Based on the frequency-weighted accelerations measured at the tool handles during the three work tasks, the sheet metal mechanics assigned to these tasks at the studied workplace are unlikely to exceed the daily vibration exposure action value (2.5 m s−2) using any of the evaluated riveting hammers. PMID:22539561

The characteristics of vibrotactile perception threshold among shipyard workers in a tropical environment.

PubMed

Tamrin, Shamsul Bahri Mohd; Jamalohdin, Mohd Nazri; Ng, Yee Guan; Maeda, Setsuo; Ali, Nurul Asyiqin Mohd

2012-01-01

The objectives of this study are to determine the prevalence of hand-arm vibration syndrome (HAVS) and the characteristics of the vibrotactile perception threshold (VPT) among users of hand-held vibrating tools working in a tropical environment. A cross sectional study was done among 47 shipyard workers using instruments and a questionnaire to determine HAVS related symptoms. The vibration acceleration magnitude was determined using a Human Vibration Meter (Maestro). A P8 Pallesthesiometer (EMSON-MAT, Poland) was used to determine the VPT of index and little finger at frequencies of 31.5 Hz and 125 Hz. The mean reference threshold shift was determined from the reference threshold shift derived from the VPT value. The results show a moderate prevalence of HAVS (49%) among the shipyard workers. They were exposed to the same high intensity level of HAVS (mean = 4.19 ± 1.94 m/s(2)) from the use of vibrating hand-held tools. The VPT values were found to be higher for both fingers and both frequencies (index, 31.5 Hz = 110.91 ± 7.36 dB, 125 Hz = 117.0 ± 10.25 dB; little, 31.5 Hz = 110.70 ± 6.75 dB, 125 Hz = 117.71 ± 10.25 dB) compared to the normal healthy population with a mean threshold shift of between 9.20 to 10.61 decibels. The frequency of 31.5 Hz had a higher percentage of positive mean reference threshold shift (index finger=93.6%, little finger=100%) compared to 125 Hz (index finger=85.1%, little finger=78.7%). In conclusion, the prevalence of HAVS was lower than those working in a cold environment; however, all workers had a higher mean VPT value compared to the normal population with all those reported as having HAVS showing a positive mean reference threshold shift of VPT value.

[Assessment of the surgeon radiation exposure during a minimally invasive TLIF: Comparison between fluoroscopy and O-arm system].

PubMed

Grelat, M; Zairi, F; Quidet, M; Marinho, P; Allaoui, M; Assaker, R

2015-08-01

Transforaminal lumbar interbody fusion with a minimally invasive approach (MIS TLIF) has become a very popular technique in the treatment of degenerative diseases of the lumbar spine, as it allows a decrease in muscle iatrogenic. However, iterative radiological controls inherent to this technique are responsible for a significant increase in exposure to ionizing radiation for the surgeon. New techniques for radiological guidance (O-arm navigation-assisted) would overcome this drawback, but this remains unproven. To analyze the exposure of the surgeon to intraoperative X-ray during a MIS TLIF under fluoroscopy and under O-arm navigation-assisted. This prospective study was conducted at the University Hospital of Lille from February to May 2013. Twelve patients underwent a MIS TLIF for the treatment of low-grade spondylolisthesis; six under standard fluoroscopy (group 1) and six under O-arm system (group 2). Passive dosimeters (rings and glasses) and active dosimeters for thorax were used to measure the radiation exposure of the surgeon. For group 1, the average time of fluoroscopy was 3.718 minutes (3.13-4.56) while no radioscopy was perform on group 2. For the first group, the average exposure dose was 12 μSv (5-20 μSv) on the thorax, 1168 μSv (510-2790 μSv) on the main hand and 179 μSv (103-486 μSv) on the lens. The exposure dose was measured zero on the second group. The maximum recommended doses can be reached, mainly for the lens. In addition to the radioprotection measures, O-arm navigation systems are safe alternatives to significantly reduce surgeon exposure. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Vibration induced white-feet: Overview and field study of vibration exposure and reported symptoms in workers

PubMed Central

Eger, Tammy; Thompson, Aaron; Leduc, Mallorie; Krajnak, Kristine; Goggins, Katie; Godwin, Alison; House, Ron

2015-01-01

BACKGROUND Workers who stand on platforms or equipment that vibrate are exposed to foot-transmitted vibration (FTV). Exposure to FTV can lead to vibration white feet/toes resulting in blanching of the toes, and tingling and numbness in the feet and toes. OBJECTIVES The objectives are 1) to review the current state of knowledge of the health risks associated with foot-transmitted vibration (FTV), and 2) to identify the characteristics of FTV and discuss the associated risk of vibration-induced injury. PARTICIPANTS Workers who operated locomotives (n = 3), bolting platforms (n = 10), jumbo drills (n = 7), raise drilling platforms (n = 4), and crushers (n = 3), participated. METHODS A tri-axial accelerometer was used to measure FTV in accordance with ISO 2631-1 guidelines. Frequency-weighted root-mean-square acceleration and the dominant frequency are reported. Participants were also asked to report pain/ache/discomfort in the hands and/or feet. RESULTS Reports of pain/discomfort/ache were highest in raise platform workers and jumbo drill operators who were exposed to FTV in the 40 Hz and 28 Hz range respectively. Reports of discomfort/ache/pain were lowest in the locomotive and crusher operators who were exposed to FTV below 10 Hz. These findings are consistent with animal studies that have shown vascular and neural damage in exposed appendages occurs at frequencies above 40 Hz. CONCLUSIONS Operators exposed to FTV at 40 Hz appear to be at greater risk of experiencing vibration induced injury. Future research is required to document the characteristics of FTV and epidemiological evidence is required to link exposure with injury. PMID:24004754

The Influence of Acute Arm Vibration on Coordination in Physical Education

ERIC Educational Resources Information Center

Erman, Alparslan

2015-01-01

Today, some researchers have focused on the impacts of new and easily applicable non-invasive methods on physical education. The purpose of this study is to examine the vibration-related acute change in rotary pursuit coordination performance soon after arm vibration. In the study, 27 students in School of Physical Education and Sport were divided…

Force illusions and drifts observed during muscle vibration.

PubMed

Reschechtko, Sasha; Cuadra, Cristian; Latash, Mark L

2018-01-01

We explored predictions of a scheme that views position and force perception as a result of measuring proprioceptive signals within a reference frame set by ongoing efferent process. In particular, this hypothesis predicts force illusions caused by muscle vibration and mediated via changes in both afferent and efferent components of kinesthesia. Healthy subjects performed accurate steady force production tasks by pressing with the four fingers of one hand (the task hand) on individual force sensors with and without visual feedback. At various times during the trials, subjects matched the perceived force using the other hand. High-frequency vibration was applied to one or both of the forearms (over the hand and finger extensors). Without visual feedback, subjects showed a drop in the task hand force, which was significantly smaller under the vibration of that forearm. Force production by the matching hand was consistently higher than that of the task hand. Vibrating one of the forearms affected the matching hand in a manner consistent with the perception of higher magnitude of force produced by the vibrated hand. The findings were consistent between the dominant and nondominant hands. The effects of vibration on both force drift and force mismatching suggest that vibration led to shifts in both signals from proprioceptors and the efferent component of perception, the referent coordinate and/or coactivation command. The observations fit the hypothesis on combined perception of kinematic-kinetic variables with little specificity of different groups of peripheral receptors that all contribute to perception of forces and coordinates. NEW & NOTEWORTHY We show that vibration of hand/finger extensors produces consistent errors in finger force perception. Without visual feedback, finger force drifted to lower values without a drift in the matching force produced by the other hand; hand extensor vibration led to smaller finger force drift. The findings fit the scheme with combined perception of kinematic-kinetic variables and suggest that vibration leads to consistent shifts of the referent coordinate and, possibly, of coactivation command to the effector.

The relationship between clinical and standardized tests for hand-arm vibration syndrome.

PubMed

Poole, C J M; Mason, H; Harding, A-H

2016-06-01

Standardized laboratory tests are undertaken to assist the diagnosis and staging of hand-arm vibration syndrome (HAVS), but the strength of the relationship between the tests and clinical stages of HAVS is unknown. To assess the relationship between the results of thermal aesthesiometry (TA), vibrotactile (VT) thresholds and cold provocation (CP) tests with the modified Stockholm scales for HAVS and to determine whether the relationship is affected by finger skin temperature. Consecutive records of workers referred to a Tier 5 HAVS assessment centre from 2006 to 2015 were identified. The diagnosis and staging of cases was undertaken from the clinical information contained in the records. Cases with alternative or mixed diagnoses were excluded and staging performed according to the modified Stockholm scale without knowledge of the results of the standardized laboratory tests. A total of 279 cases of HAVS were analysed. Although there was a significant trend for sensorineural (SN) and vascular scores to increase with clinical stage (P < 0.01), there was no significant difference in scores between 2SN early and 2SN late or between 2SN late and 3SN. There was moderate correlation between the TA and VT scores and the clinical SN stages (r = 0.6). This correlation did not change when subjects were divided into those with a finger skin temperature <30 and >30°C. CP scores distributed bimodally and correlated poorly with clinical staging (r = 0.2). Standardized SN tests distinguish between the lower Stockholm stages, but not above 2SN early. This has implications for health surveillance and UK policy. © Crown copyright 2016.

Accelerometry Measuring the Outcome of Robot-Supported Upper Limb Training in Chronic Stroke: A Randomized Controlled Trial

PubMed Central

Lemmens, Ryanne J. M.; Timmermans, Annick A. A.; Janssen-Potten, Yvonne J. M.; Pulles, Sanne A. N. T. D.; Geers, Richard P. J.; Bakx, Wilbert G. M.; Smeets, Rob J. E. M.; Seelen, Henk A. M.

2014-01-01

Purpose This study aims to assess the extent to which accelerometers can be used to determine the effect of robot-supported task-oriented arm-hand training, relative to task-oriented arm-hand training alone, on the actual amount of arm-hand use of chronic stroke patients in their home situation. Methods This single-blind randomized controlled trial included 16 chronic stroke patients, randomly allocated using blocked randomization (n = 2) to receive task-oriented robot-supported arm-hand training or task-oriented (unsupported) arm-hand training. Training lasted 8 weeks, 4 times/week, 2×30 min/day using the (T-)TOAT ((Technology-supported)-Task-Oriented-Arm-Training) method. The actual amount of arm-hand use, was assessed at baseline, after 8 weeks training and 6 months after training cessation. Duration of use and intensity of use of the affected arm-hand during unimanual and bimanual activities were calculated. Results Duration and intensity of use of the affected arm-hand did not change significantly during and after training, with or without robot-support (i.e. duration of use of unimanual use of the affected arm-hand: median difference of −0.17% in the robot-group and −0.08% in the control group between baseline and after training cessation; intensity of the affected arm-hand: median difference of 3.95% in the robot-group and 3.32% in the control group between baseline and after training cessation). No significant between-group differences were found. Conclusions Accelerometer data did not show significant changes in actual amount of arm-hand use after task-oriented training, with or without robot-support. Next to the amount of use, discrimination between activities performed and information about quality of use of the affected arm-hand are essential to determine actual arm-hand performance. Trial Registration Controlled-trials.com ISRCTN82787126 PMID:24823925

Vibrotactile sense and hand symptoms in blue collar workers in a manufacturing industry.

PubMed Central

Flodmark, B T; Lundborg, G

1997-01-01

OBJECTIVES: To study whether vibrotactile sense combined with questionnaires (subjective complaints) and a clinical examination (including scoring of the Stockholm workshop scale (sensorineural staging)) could serve as a screening procedure, in the health care service, for sensorineural symptoms. A group of blue collar workers exposed to vibration in a manufacturing industry (rock crushing plants) was used as the study group. Another group of workers not exposed to vibration but subjected to heavy manual work served as the control group. METHODS: Vibrotactile sense was determined. The index and the little fingers of both hands were investigated. A clinical examination was performed. Questionnaires were used for exposure data and for assessment of symptoms. RESULTS: Important findings were that impairment in vibrotactile sense correlated with impairment in grip force, cold sensitivity, and other sensorineural symptoms--such as numbness and tendency to drop items. Clinical findings such as Phalen's test and two point discrimination were related only in those workers with the poorest vibrotactile sense. There was a relation between vibrotactile sense and the Stockholm workshop scale (sensorineural staging) for the sensorineural symptoms. Muscle and joint problems were more often seen in workers with decreased vibrotactile sense. CONCLUSIONS: Tactilometry for assessment of vibrotactile sense is a useful tool in assessing and evaluating the severity of vibration induced neuromuscular symptoms and verifying the patients' clinical complaints. Heavy manual work without exposure to vibration may contribute to impairment of vibrotactile sense. The relation between impairment in vibrotactile sense and grip strength indicates that impaired sensory feedback may contribute to muscle weakness. PMID:9470896

A Biomechanical Assessment of Hand/Arm Force with Pneumatic Nail Gun Actuation Systems.

PubMed

Lowe, Brian D; Albers, James; Hudock, Stephen D

2014-09-01

A biomechanical model is presented, and combined with measurements of tip press force, to estimate total user hand force associated with two pneumatic nail gun trigger systems. The contact actuation trigger (CAT) can fire a nail when the user holds the trigger depressed first and then "bumps" the nail gun tip against the workpiece. With a full sequential actuation trigger (SAT) the user must press the tip against the workpiece prior to activating the trigger. The SAT is demonstrably safer in reducing traumatic injury risk, but increases the duration (and magnitude) of tip force exertion. Time integrated (cumulative) hand force was calculated for a single user from measurements of the tip contact force with the workpiece and transfer time between nails as inputs to a static model of the nail gun and workpiece in two nailing task orientations. The model shows the hand force dependence upon the orientation of the workpiece in addition to the trigger system. Based on standard time allowances from work measurement systems (i.e. Methods-Time Measurement - 1) it is proposed that efficient application of hand force with the SAT in maintaining tip contact can reduce force exertion attributable to the sequential actuation trigger to 2-8% (horizontal nailing) and 9-20% (vertical nailing) of the total hand/arm force. The present model is useful for considering differences in cumulative hand/arm force exposure between the SAT and CAT systems and may explain the appeal of the CAT trigger in reducing the user's perception of muscular effort.

A Biomechanical Assessment of Hand/Arm Force with Pneumatic Nail Gun Actuation Systems

PubMed Central

Lowe, Brian D.; Albers, James; Hudock, Stephen D.

2015-01-01

A biomechanical model is presented, and combined with measurements of tip press force, to estimate total user hand force associated with two pneumatic nail gun trigger systems. The contact actuation trigger (CAT) can fire a nail when the user holds the trigger depressed first and then “bumps” the nail gun tip against the workpiece. With a full sequential actuation trigger (SAT) the user must press the tip against the workpiece prior to activating the trigger. The SAT is demonstrably safer in reducing traumatic injury risk, but increases the duration (and magnitude) of tip force exertion. Time integrated (cumulative) hand force was calculated for a single user from measurements of the tip contact force with the workpiece and transfer time between nails as inputs to a static model of the nail gun and workpiece in two nailing task orientations. The model shows the hand force dependence upon the orientation of the workpiece in addition to the trigger system. Based on standard time allowances from work measurement systems (i.e. Methods-Time Measurement - 1) it is proposed that efficient application of hand force with the SAT in maintaining tip contact can reduce force exertion attributable to the sequential actuation trigger to 2–8% (horizontal nailing) and 9–20% (vertical nailing) of the total hand/arm force. The present model is useful for considering differences in cumulative hand/arm force exposure between the SAT and CAT systems and may explain the appeal of the CAT trigger in reducing the user’s perception of muscular effort. PMID:26321780

Sensor design for outdoor racing bicycle field testing for human vibration comfort evaluation

NASA Astrophysics Data System (ADS)

Vanwalleghem, Joachim; De Baere, Ives; Loccufier, Mia; Van Paepegem, Wim

2013-09-01

This paper is concerned with the vibrational comfort evaluation of the cyclist when cycling a rough surface. Outdoor comfort tests have so far only been done through instrumenting the bicycle with accelerometers. This work instruments a racing bicycle with custom-made contact force sensors and velocity sensors to acquire human comfort through the absorbed power method. Comfort evaluation is assessed at the hand-arm and seat interface of the cyclist with the bicycle. By means of careful finite-element analysis for designing the force gauges at the handlebar and the seat combined with precise calibration of both force and velocity sensors, all sensors have proven to work properly. Initial field tests are focused on the proper functioning of the designed sensors and their suitability for vibration comfort measurements. Tests on a cobblestone road reveal that the outcome of the absorbed power values is within the same range as those from laboratory tests found in the literature. This sensor design approach for outdoor testing with racing bicycles may give a new interpretation on evaluating the cyclist's comfort since the vibrational load is not only quantified in terms of acceleration but also in terms of force and velocity at the bicycle-cyclist contact points.

Participatory ergonomic intervention versus strength training on chronic pain and work disability in slaughterhouse workers: study protocol for a single-blind, randomized controlled trial.

PubMed

Sundstrup, Emil; Jakobsen, Markus D; Andersen, Christoffer H; Jay, Kenneth; Persson, Roger; Aagaard, Per; Andersen, Lars L

2013-02-21

The prevalence of musculoskeletal pain in the shoulder, arm and hand is high among slaughterhouse workers, allegedly due to the highly repetitive and forceful exposure of these body regions during work. Work disability is a common consequence of these pains. Lowering the physical exposure through ergonomics intervention is the traditional strategy to reduce the workload. An alternative strategy could be to increase physical capacity of the worker through strength training. This study investigates the effect of two contrasting interventions, participatory ergonomics versus strength training on pain and work disability in slaughterhouse workers with chronic pain. 66 slaughterhouse workers were allocated to 10 weeks of (1) strength training of the shoulder, arm and hand muscles for 3 x 10 minutes per week, or (2) participatory ergonomics involving counseling on workstation adjustment and optimal use of work tools (~usual care control group). Inclusion criteria were (1) working at a slaughterhouse for at least 30 hours per week, (2) pain intensity in the shoulder, elbow/forearm, or hand/wrist of at least 3 on a 0-10 VAS scale during the last three months, (3) pain lasting for more than 3 months, (4) frequent pain (at least 3 days per week) (5) at least moderate work disability, (6) no strength training during the last year, (7) no ergonomics instruction during the last year.Perceived pain intensity (VAS scale 0-10) of the shoulder, elbow/forearm and hand/wrist (primary outcome) and Disability of the Arm, Shoulder and Hand (Work module, DASH questionnaire) were measured at baseline and 10-week follow-up. Further, total muscle tenderness score and muscle function were assessed during clinical examination at baseline and follow-up. This RCT study will provide experimental evidence of the effectiveness of contrasting work-site interventions aiming at reducing chronic pain and work disability among employees engaged in repetitive and forceful work. ClinicalTrials.gov:NCT01671267.

Cortical activation pattern during shoulder simple versus vibration exercises: a functional near infrared spectroscopy study.

PubMed

Jang, Sung Ho; Yeo, Sang Seok; Lee, Seung Hyun; Jin, Sang Hyun; Lee, Mi Young

2017-08-01

To date, the cortical effect of exercise has not been fully elucidated. Using the functional near infrared spectroscopy, we attempted to compare the cortical effect between shoulder vibration exercise and shoulder simple exercise. Eight healthy subjects were recruited for this study. Two different exercise tasks (shoulder vibration exercise using the flexible pole and shoulder simple exercise) were performed using a block paradigm. We measured the values of oxygenated hemoglobin in the four regions of interest: the primary sensory-motor cortex (SM1 total, arm somatotopy, and leg and trunk somatotopy), the premotor cortex, the supplementary motor area, and the prefrontal cortex. During shoulder vibration exercise and shoulder simple exercise, cortical activation was observed in SM1 (total, arm somatotopy, and leg and trunk somatotopy), premotor cortex, supplementary motor area, and prefrontal cortex. Higher oxygenated hemoglobin values were also observed in the areas of arm somatotopy of SM1 compared with those of other regions of interest. However, no significant difference in the arm somatotopy of SM1 was observed between the two exercises. By contrast, in the leg and trunk somatotopy of SM1, shoulder vibration exercise led to a significantly higher oxy-hemoglobin value than shoulder simple exercise. These two exercises may result in cortical activation effects for the motor areas relevant to the shoulder exercise, especially in the arm somatotopy of SM1. However, shoulder vibration exercise has an additional cortical activation effect for the leg and trunk somatotopy of SM1.

Predicting Forearm Physical Exposures During Computer Work Using Self-Reports, Software-Recorded Computer Usage Patterns, and Anthropometric and Workstation Measurements.

PubMed

Huysmans, Maaike A; Eijckelhof, Belinda H W; Garza, Jennifer L Bruno; Coenen, Pieter; Blatter, Birgitte M; Johnson, Peter W; van Dieën, Jaap H; van der Beek, Allard J; Dennerlein, Jack T

2017-12-15

Alternative techniques to assess physical exposures, such as prediction models, could facilitate more efficient epidemiological assessments in future large cohort studies examining physical exposures in relation to work-related musculoskeletal symptoms. The aim of this study was to evaluate two types of models that predict arm-wrist-hand physical exposures (i.e. muscle activity, wrist postures and kinematics, and keyboard and mouse forces) during computer use, which only differed with respect to the candidate predicting variables; (i) a full set of predicting variables, including self-reported factors, software-recorded computer usage patterns, and worksite measurements of anthropometrics and workstation set-up (full models); and (ii) a practical set of predicting variables, only including the self-reported factors and software-recorded computer usage patterns, that are relatively easy to assess (practical models). Prediction models were build using data from a field study among 117 office workers who were symptom-free at the time of measurement. Arm-wrist-hand physical exposures were measured for approximately two hours while workers performed their own computer work. Each worker's anthropometry and workstation set-up were measured by an experimenter, computer usage patterns were recorded using software and self-reported factors (including individual factors, job characteristics, computer work behaviours, psychosocial factors, workstation set-up characteristics, and leisure-time activities) were collected by an online questionnaire. We determined the predictive quality of the models in terms of R2 and root mean squared (RMS) values and exposure classification agreement to low-, medium-, and high-exposure categories (in the practical model only). The full models had R2 values that ranged from 0.16 to 0.80, whereas for the practical models values ranged from 0.05 to 0.43. Interquartile ranges were not that different for the two models, indicating that only for some physical exposures the full models performed better. Relative RMS errors ranged between 5% and 19% for the full models, and between 10% and 19% for the practical model. When the predicted physical exposures were classified into low, medium, and high, classification agreement ranged from 26% to 71%. The full prediction models, based on self-reported factors, software-recorded computer usage patterns, and additional measurements of anthropometrics and workstation set-up, show a better predictive quality as compared to the practical models based on self-reported factors and recorded computer usage patterns only. However, predictive quality varied largely across different arm-wrist-hand exposure parameters. Future exploration of the relation between predicted physical exposure and symptoms is therefore only recommended for physical exposures that can be reasonably well predicted. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Does combined strength training and local vibration improve isometric maximum force? A pilot study.

PubMed

Goebel, Ruben; Haddad, Monoem; Kleinöder, Heinz; Yue, Zengyuan; Heinen, Thomas; Mester, Joachim

2017-01-01

The aim of the study was to determine whether a combination of strength training (ST) and local vibration (LV) improved the isometric maximum force of arm flexor muscles. ST was applied to the left arm of the subjects; LV was applied to the right arm of the same subjects. The main aim was to examine the effect of LV during a dumbbell biceps curl (Scott Curl) on isometric maximum force of the opposite muscle among the same subjects. It is hypothesized, that the intervention with LV produces a greater gain in isometric force of the arm flexors than ST. Twenty-seven collegiate students participated in the study. The training load was 70% of the individual 1 RM. Four sets with 12 repetitions were performed three times per week during four weeks. The right arm of all subjects represented the vibration trained body side (VS) and the left arm served as the traditional trained body side (TTS). A significant increase of isometric maximum force in both body sides (Arms) occurred. VS, however, significantly increased isometric maximum force about 43% in contrast to 22% of the TTS. The combined intervention of ST and LC improves isometric maximum force of arm flexor muscles. III.

The physiotherapeutic context of loss of dominant arm function due to occupational accidents.

PubMed

Kostiukow, Anna; Kaluga, Elżbieta; Samborski, Włodzimierz; Rostkowska, Elżbieta

2016-12-23

The study examines the problem of dominant arm function loss in rural adult patients due to work-related accidents. The types of risks involved in farmyard work include falling from a height, manually moving loads, overturning/accident whilst driving an agricultural tractor, noise and vibration, use of pesticides, and the risk of being cut or injured. The study focuses on adaptation of the non-dominant arm. The main aim of the study was evaluation of visual-motor coordination on the basis of performance of the non-dominant hand in patients after the loss of function of the dominant arm. The research sample consisted of 52 patients with a permanent or temporary loss of function or severely limited function of the dominant arm. The subjects were patients with arm amputations due to various occupational injuries sustained while operating agricultural and construction machinery and forestry equipment, following traumas or complicated medical surgeries of the arm, or due to car accidents. The following tests were applied in the analysis: I) Dufour cross-shaped apparatus test for assessing visual motor-coordination; II) paper-and-pencil tests and the Relay Baton motor fitness test; III) anthropometric measurements; IV) Edinburgh Handedness Inventory; and V) a questionnaire survey. The results of the apparatus and motor tests indicate the same tendency: reaction to stimuli measured on the basis of performance of the non-dominant arm is longer in shorter and older patients. Visual-motor coordination, as measured by the performance of the non-dominant arm, is significantly affected by the subject's body height and arm length.

Active Manual Movement Improves Directional Perception of Illusory Force.

PubMed

Amemiya, Tomohiro; Gomi, Hiroaki

2016-01-01

Active touch sensing is known to facilitate the discrimination or recognition of the spatial properties of an object from the movement of tactile sensors on the skin and by integrating proprioceptive feedback about hand positions or motor commands related to ongoing hand movements. On the other hand, several studies have reported that tactile processing is suppressed by hand movement. Thus, it is unclear whether or not the active exploration of force direction by using hand or arm movement improves the perception of the force direction. Here, we show that active manual movement in both the rotational and translational directions enhances the precise perception of the force direction. To make it possible to move a hand in space without any physical constraints, we have adopted a method of inducing the sensation of illusory force by asymmetric vibration. We found that the precision of the perceived force direction was significantly better when the shoulder is rotated medially and laterally. We also found that directional errors supplied by the motor response of the perceived force were smaller than those resulting from perceptual judgments between visual and haptic directional stimuli. These results demonstrate that active manual movement boosts the precision of the perceived direction of an illusory force.

Effect of higher frequency components and duration of vibration on bone tissue alterations in the rat-tail model

PubMed Central

PEELUKHANA, Srikara V.; GOENKA, Shilpi; KIM, Brian; KIM, Jay; BHATTACHARYA, Amit; STRINGER, Keith F.; BANERJEE, Rupak K.

2015-01-01

To formulate more accurate guidelines for musculoskeletal disorders (MSD) linked to Hand-Arm Vibration Syndrome (HAVS), delineation of the response of bone tissue under different frequencies and duration of vibration needs elucidation. Rat-tails were vibrated at 125 Hz (9 rats) and 250 Hz (9 rats), at 49 m/s2, for 1D (6 rats), 5D (6 rats) and 20D (6 rats); D=days (4 h/d). Rats in the control group (6 rats for the vibration groups; 2 each for 1D, 5D, and 20D) were left in their cages, without being subjected to any vibration. Structural and biochemical damages were quantified using empty lacunae count and nitrotyrosine signal-intensity, respectively. One-way repeated-measure mixed-model ANOVA at p<0.05 level of significance was used for analysis. In the cortical bone, structural damage quantified through empty lacunae count was significant (p<0.05) at 250 Hz (10.82 ± 0.66) in comparison to the control group (7.41 ± 0.76). The biochemical damage was significant (p<0.05) at both the 125 Hz and 250 Hz vibration frequencies. The structural damage was significant (p<0.05) at 5D for cortical bone while the trabecular bone showed significant (p<0.05) damage at 20D time point. Further, the biochemical damage increased with increase in the duration of vibration with a significant (p<0.05) damage observed at 20D time point and a near significant change (p=0.08) observed at 5D time point. Structural and biochemical changes in bone tissue are dependent upon higher vibration frequencies of 125 Hz, 250 Hz and the duration of vibration (5D, 20D). PMID:25843564

Imaging Organ of Corti Vibration Using Fourier-Domain OCT

NASA Astrophysics Data System (ADS)

Choudhury, Niloy; Chen, Fangyi; Fridberger, Anders; Zha, Dingjun; Jacques, Steven L.; Wang, Ruikang K.; Nuttall, Alfred L.

2011-11-01

Measuring the sound stimulated vibration from various structures in the organ of Corti is important in understanding how the small vibrations are amplified and detected. In this study we examine the feasibility of using phase-sensitive Fourier domain optical coherence tomography (PSFD-OCT) to measure vibration of the cellular structures of the organ of Corti. PSFD-OCT is a low coherence interferrometry system where the interferrogram is detected as a function of wavelength. The phase of the Fourier transformation of the detected spectra contains path deference (between the sample arm and the reference arm) information of the interferometer. In PSFD-OCT this phase is measured as a function of time and thus any time dependent change in the path difference between the sample arm and the reference arm can be detected. In the experiment, we used an in vitro preparation of the guinea pig cochlea and made a surgical opening at the apical end to access the organ of Corti. By applying tones with different frequencies via the intact middle ear, we recorded the structural vibration inside the organ of Corti. Vibration amplitude and phase of different substructures were mapped on a cross-section view of the organ of Corti. Although the measurements were made at the apical turn of the cochlea, it will be possible to make vibration measurement from various turns of the cochlea. The noise floor of the system was 0.3 nm, calibrated using a piezo stack as a calibrator.

Changes in arm-hand function and arm-hand skill performance in patients after stroke during and after rehabilitation.

PubMed

Franck, Johan Anton; Smeets, Rob Johannes Elise Marie; Seelen, Henk Alexander Maria

2017-01-01

Arm-hand rehabilitation programs applied in stroke rehabilitation frequently target specific populations and thus are less applicable in heterogeneous patient populations. Besides, changes in arm-hand function (AHF) and arm-hand skill performance (AHSP) during and after a specific and well-described rehabilitation treatment are often not well evaluated. This single-armed prospective cohort study featured three subgroups of stroke patients with either a severely, moderately or mildly impaired AHF. Rehabilitation treatment consisted of a Concise_Arm_and_hand_ Rehabilitation_Approach_in_Stroke (CARAS). Measurements at function and activity level were performed at admission, clinical discharge, 3, 6, 9 and 12 months after clinical discharge. Eighty-nine stroke patients (M/F:63/23; mean age:57.6yr (+/-10.6); post-stroke time:29.8 days (+/-20.1)) participated. All patients improved on AHF and arm-hand capacity during and after rehabilitation, except on grip strength in the severely affected subgroup. Largest gains occurred in patients with a moderately affected AHF. As to self-perceived AHSP, on average, all subgroups improved over time. A small percentage of patients declined regarding self-perceived AHSP post-rehabilitation. A majority of stroke patients across the whole arm-hand impairment severity spectrum significantly improved on AHF, arm-hand capacity and self-perceived AHSP. These were maintained up to one year post-rehabilitation. Results may serve as a control condition in future studies.

Space hands-on universe telescope and orbiting wide-angle light-collector telescope to be built on the Japanese experiment module exposure facility of the international space station

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

Takahashi, Y.; Ebisuzaki, T.; Pennypacker, C.

1999-01-01

A concept study to build great observatories on, and deploy from, the ISS is presented. Use of the ISS infra-structure including robotic arms and astronauts{close_quote} EVA would permit a construction of very large optical telescopes. We envisage that the second phase of the ISS after its initial construction can landmark a new era for both ISS and Space Sciences. Ultimately, this study would plan a 10-or 20-meter class space telescope. For its first step, we envisioned an immediate extension of the Exposed Facility of ISS for building a {open_quotes}Work-bench{close_quotes} for this purpose. Initial activities can begin with two modest-sized telescopesmore » soon after the ISS construction. These early missions being studied are space Hands-On Universe Telescope (SHOUT) and Orbiting Wide-angle Light-collector (OWL). SHOUT is a 1-m telescope for science education. It will be built and adjusted on the exposure module of the Japanese Experiment Module (JEM) of the International Space Station by using a robotic arm and the EVA of astronauts. We also seek the possibility to release it from ISS after its perfection on orbit, so that it is free from the vibrations and gas contaminations on and around the ISS. SHOUT is an engineering prototype of 10-m Space Telescope (Space SUBARU Telescope). It would be scaled from the Space-SUBARU telescope so that the testing with the SHOUT would warrant the required specifications for the 10-meter Space-SUBARU construction on the ISS. The goal of the test with the SHOUT is to warrant a spatial resolution of 0.01 arc-seconds using the active/adaptive optics. It will test the following three major engineering challenges: (1) active/adaptive optics in space; (2) building of large structures by astronauts; and (3) release of a spacecraft from ISS to a free-flying orbit. The present feasibility study for the next generation great observatories that are to be built on the JEM Exposure Facility (EF) has been already funded by the Japan Space Forum, under the auspices of the National Space Development Agency (NASDA) of Japan. Included in this study are SHOUT, Space SUBARU telescope as well as OWL, Large Area gamma-ray Telescope (LAGT), and Space Submilimeter and Infrared Telescope (S-SIT). {copyright} {ital 1999 American Institute of Physics.}« less

The use of a digital computer for investigation of the dynamic characteristics of a man while pressing vertically downward with the straight arm on the handle of a vibrator (instrument)

NASA Technical Reports Server (NTRS)

Zazhivikhina, A. I.; Rosin, G. S.; Ryzhov, Y. I.

1973-01-01

The dynamic characteristics of a man were investigated by the resonance method, by means of recordings of the amplitude-frequency characteristics of a vibrator straight arm human body system on a standard automatic recorder. Experiments were carried out with a specially constructed vibrator, the moving system of which was fastened to a bronze suspension with small losses. Vibrations of the handle, fastened to the moving system, were recorded with an accelerometer. The mass of the moving system m, rigidity of the suspension k and friction coefficient r of the vibrator (calibration) were determined by exact formulas.

Risk factors for Raynaud's phenomenon among workers in poultry slaughterhouses and canning factories.

PubMed

Kaminski, M; Bourgine, M; Zins, M; Touranchet, A; Verger, C

1997-04-01

Apart from the use of vibrating tools, little is known about risk factors for Raynaud's phenomenon. However, it has been hypothesized that this disorder may have a multifactorial aetiology, involving potential causal or triggering factors which can be found in the workplace. The objective of the study is to identify individual and occupational risk factors of Raynaud's phenomenon in a population of workers not exposed to vibration, but exposed to cold. The survey was carried out in 1987-1988 in 17 poultry slaughterhouses and six canning factories and included 1474 employees. Data were collected at the annual visit to the occupational health physician. Finger sensitivity to cold and Raynaud's phenomenon were identified from a list of symptoms occurring from exposure to cold. The role of potential risk factors was assessed using multiple logistic regression. A high prevalence of symptoms of finger sensitivity to cold was observed. Raynaud's phenomenon was more common in women than in men, was related to family history of the disease but not to smoking or alcohol consumption. After controlling for non-occupational factors, the following working conditions appeared as risk factors for Raynaud's phenomenon: use of plastic gloves, less than four rest breaks, breaks in an unheated place, continual repetition of the same series of operations, exertion of the arm or hand and being able to think of something else while working. The study showed that a number of working conditions were associated with an increased risk of Raynaud's phenomenon and finger sensitivity to cold. Changes in working conditions might reduce the risk of this disorder in the food processing industry.

Changes in arm-hand function and arm-hand skill performance in patients after stroke during and after rehabilitation

PubMed Central

Smeets, Rob Johannes Elise Marie; Seelen, Henk Alexander Maria

2017-01-01

Background Arm-hand rehabilitation programs applied in stroke rehabilitation frequently target specific populations and thus are less applicable in heterogeneous patient populations. Besides, changes in arm-hand function (AHF) and arm-hand skill performance (AHSP) during and after a specific and well-described rehabilitation treatment are often not well evaluated. Method This single-armed prospective cohort study featured three subgroups of stroke patients with either a severely, moderately or mildly impaired AHF. Rehabilitation treatment consisted of a Concise_Arm_and_hand_ Rehabilitation_Approach_in_Stroke (CARAS). Measurements at function and activity level were performed at admission, clinical discharge, 3, 6, 9 and 12 months after clinical discharge. Results Eighty-nine stroke patients (M/F:63/23; mean age:57.6yr (+/-10.6); post-stroke time:29.8 days (+/-20.1)) participated. All patients improved on AHF and arm-hand capacity during and after rehabilitation, except on grip strength in the severely affected subgroup. Largest gains occurred in patients with a moderately affected AHF. As to self-perceived AHSP, on average, all subgroups improved over time. A small percentage of patients declined regarding self-perceived AHSP post-rehabilitation. Conclusions A majority of stroke patients across the whole arm-hand impairment severity spectrum significantly improved on AHF, arm-hand capacity and self-perceived AHSP. These were maintained up to one year post-rehabilitation. Results may serve as a control condition in future studies. PMID:28614403

Effect of afferent feedback and central motor commands on soleus H-reflex suppression during arm cycling.

PubMed

Hundza, S R; de Ruiter, Geoff C; Klimstra, M; Zehr, E Paul

2012-12-01

Suppression of soleus H-reflex amplitude in stationary legs is seen during rhythmic arm cycling. We examined the influence of various arm-cycling parameters on this interlimb reflex modulation to determine the origin of the effect. We previously showed the suppression to be graded with the frequency of arm cycling but not largely influenced by changes in peripheral input associated with crank length. Here, we more explicitly explored the contribution of afferent feedback related to arm movement on the soleus H-reflex suppression. We explored the influence of load and rate of muscle stretch by manipulating crank-load and arm-muscle vibration during arm cycling. Furthermore, internally driven ("Active") and externally driven ("Passive") arm cycling was compared. Soleus H-reflexes were evoked with tibial nerve stimulation during stationary control and rhythmic arm-cycling conditions, including: 1) six different loads; 2) with and without vibration to arm muscles; and 3) Active and Passive conditions. No significant differences were seen in the level of suppression between the different crank loads or between conditions with and without arm-muscle vibration. Furthermore, in contrast to the clear effect seen during active cycling, passive arm cycling did not significantly suppress the soleus H-reflex amplitude. Current results, in conjunction with previous findings, suggest that the afferent feedback examined in these studies is not the primary source responsible for soleus H-reflex suppression. Instead, it appears that central motor commands (supraspinal or spinal in origin) associated with frequency of arm cycling are relatively more dominant sources.

Flame retardant exposure assessment: findings from a behavioral intervention study.

PubMed

Gibson, Elizabeth A; Stapleton, Heather M; Calero, Lehyla; Holmes, Darrell; Burke, Kimberly; Martinez, Rodney; Cortes, Boris; Nematollahi, Amy; Evans, David; Herbstman, Julie B

2018-06-28

Polybrominated diphenyl ethers (PBDEs) have been largely replaced by organophosphate flame retardants (OPFRs) and alternative brominated flame retardants (Alt-BFRs) to meet flammability requirements. Humans are ubiquitously exposed to some variety of flame retardants through contact with consumer products directly or through household dust. To evaluate the effectiveness of house cleaning and hand washing practices to reduce exposure to flame retardants, we measured concentrations in dermal hand wipes and urinary metabolites before and after assignment to two consecutive interventions. We selected 32 mother and child dyads from an existing cohort. This analysis focuses on mothers. Participants provided baseline measurements (urine, hand wipes, and questionnaires) and were then assigned for 1 week to either a house cleaning (including instruction on proper technique and cleaning supplies) or hand washing (including instruction on proper technique and soaps) intervention arm. For the second week, participants were assigned to the second intervention in addition to their initial assignment, thus all subjects both washed their hands and cleaned according to the intervention guidelines during week 2. We collected measurements at the end of weeks 1 and 2. We found reductions in urinary analytes after week 1 of house cleaning (BCIPHIPP and ip-DPHP), week 1 of hand washing (BCIPP, BCIPHIPP, and tbutyl-DPHP), and week 2 of combined interventions (BCIPHIPP and tbutyl-DPHP), compare to baseline. We found no significant decline in hand wipes in the entire sample but did find reductions after week 1 of house cleaning (BDE 209), week 1 of hand washing (TCEP), and week 2 of combined interventions (TDCIPP and BDE 209) in women with exposure above the median at baseline (verified through simulations). Exposure to individual flame retardants was reduced by about half, in some cases, by 1 week of increased hand washing, house cleaning to reduce dust, or combined activities.

Influence of Visual Prism Adaptation on Auditory Space Representation.

PubMed

Pochopien, Klaudia; Fahle, Manfred

2017-01-01

Prisms shifting the visual input sideways produce a mismatch between the visual versus felt position of one's hand. Prism adaptation eliminates this mismatch, realigning hand proprioception with visual input. Whether this realignment concerns exclusively the visuo-(hand)motor system or it generalizes to acoustic inputs is controversial. We here show that there is indeed a slight influence of visual adaptation on the perceived direction of acoustic sources. However, this shift in perceived auditory direction can be fully explained by a subconscious head rotation during prism exposure and by changes in arm proprioception. Hence, prism adaptation does only indirectly generalize to auditory space perception.

Left-handed skeletally mature baseball players have smaller humeral retroversion in the throwing arm than right-handed players.

PubMed

Takenaga, Tetsuya; Goto, Hideyuki; Sugimoto, Katsumasa; Tsuchiya, Atsushi; Fukuyoshi, Masaki; Nakagawa, Hiroki; Nozaki, Masahiro; Takeuchi, Satoshi; Otsuka, Takanobu

2017-12-01

It is known that the humeral retroversion of baseball players is greater in the throwing arm than in the nonthrowing arm. An investigation measuring dry bone specimens also showed that the right humerus had greater retroversion than the left. Considering these facts, it was hypothesized that humeral retroversion would differ between right- and left-handed players. This study aimed to compare the bilateral humeral retroversion between right- and left-handed skeletally mature baseball players. We investigated 260 (196 right-handed and 64 left-handed) male baseball players who belonged to a college or amateur team. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique (humeral torsion angle [HTA]) as described by previous studies. Analysis of covariance, adjusted for handedness and baseball position, assessed the effect of throwing arm dominance on HTA. In comparison of the throwing arm, HTA was significantly smaller in left-handed (left humerus) than in right-handed (right humerus) players (77° vs. 81°; P < .001). In comparison of the nonthrowing arm, HTA was significantly greater in left-handed (right humerus) than in right-handed (left humerus) players (73° vs. 69°; P < .001). The mean side-to-side difference of HTA was significantly smaller in left-handed than in right-handed players (3° vs. 12°; P < .001). Humeral retroversion of left-handed skeletally mature baseball players was significantly smaller in the throwing arm, greater in the nonthrowing arm, and smaller in side-to-side differences than that of right-handed players. These findings may be key to understanding some of the biomechanical differences between right- and left-handed baseball players. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Evaluating the effectiveness of gloves in reducing the hazards of hand-transmitted vibration.

PubMed

Griffin, M J

1998-05-01

A method of evaluating the effectiveness of gloves in reducing the hazards of hand-transmitted vibration is proposed. The glove isolation effectiveness was calculated from: (a) the measured transmissibility of a glove, (b) the vibration spectrum on the handle of a specific tool (or class of tools), and (c) the frequency weighting indicating the degree to which different frequencies of vibration cause injury. With previously reported tool vibration spectra and glove transmissibilities (from 10-1000 Hz), the method was used to test 10 gloves with 20 different powered tools. The frequency weighting for hand-transmitted vibration advocated in British standard 6842 (1987) and international standard 5349 (1986) greatly influences the apparent isolation effectiveness of gloves. With the frequency weighting, the gloves had little effect on the transmission of vibration to the hand from most of the tools. Only for two or three tools (those dominated by high frequency vibration) did any glove provide useful attenuation. Without the frequency weighting, some gloves showed useful attenuation of the vibration on most powered tools. In view of the uncertain effect of the vibration frequency in the causation of disorders from hand-transmitted vibration, it is provisionally suggested that the wearing of a glove by the user of a particular vibratory tool could be encouraged if the glove reduces the transmission of vibration when it is evaluated without the frequency weighting and does not increase the vibration when it is evaluated with the frequency weighting. A current international standard for the measurement and evaluation of the vibration transmitted by gloves can classify a glove as an antivibration glove when it provides no useful attenuation of vibration, whereas a glove providing useful attenuation of vibration on a specific tool can fail the test.

Active Vibration Control of a Large Flexible Manipulator by Inertial Force and Joint Torque. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Lee, Soo Han

1988-01-01

The efficiency and positional accuracy of a lightweight flexible manipulator are limited by its flexural vibrations, which last after a gross motion is completed. The vibration delays subsequent operations. In the proposed work, the vibration is suppressed by inertial force of a small arm in addition to the joint actuators and passive damping treatment. The proposed approach is: (1) Dynamic modeling of a combined system, a large flexible manipulator and a small arm, (2) Determination of optimal sensor location and controller algorithm, and (3) Verification of the fitness of model and the performance of controller.

Summary of compliant and multi-arm control at NASA. Langley Research Center

NASA Technical Reports Server (NTRS)

Harrison, Fenton W.

1992-01-01

The topics are presented in viewgraph form and include the: single arm system, single arm axis system, single arm control systems, single arm hand controller axis system, single arm position axis system, single arm vision axis system, single arm force axis system, multi-arm system, multi-arm axis system, and the dual arm hand control axis system with control signals.

The relationship between inadvertent ingestion and dermal exposure pathways: a new integrated conceptual model and a database of dermal and oral transfer efficiencies.

PubMed

Gorman Ng, Melanie; Semple, Sean; Cherrie, John W; Christopher, Yvette; Northage, Christine; Tielemans, Erik; Veroughstraete, Violaine; Van Tongeren, Martie

2012-11-01

Occupational inadvertent ingestion exposure is ingestion exposure due to contact between the mouth and contaminated hands or objects. Although individuals are typically oblivious to their exposure by this route, it is a potentially significant source of occupational exposure for some substances. Due to the continual flux of saliva through the oral cavity and the non-specificity of biological monitoring to routes of exposure, direct measurement of exposure by the inadvertent ingestion route is challenging; predictive models may be required to assess exposure. The work described in this manuscript has been carried out as part of a project to develop a predictive model for estimating inadvertent ingestion exposure in the workplace. As inadvertent ingestion exposure mainly arises from hand-to-mouth contact, it is closely linked to dermal exposure. We present a new integrated conceptual model for dermal and inadvertent ingestion exposure that should help to increase our understanding of ingestion exposure and our ability to simultaneously estimate exposure by the dermal and ingestion routes. The conceptual model consists of eight compartments (source, air, surface contaminant layer, outer clothing contaminant layer, inner clothing contaminant layer, hands and arms layer, perioral layer, and oral cavity) and nine mass transport processes (emission, deposition, resuspension or evaporation, transfer, removal, redistribution, decontamination, penetration and/or permeation, and swallowing) that describe event-based movement of substances between compartments (e.g. emission, deposition, etc.). This conceptual model is intended to guide the development of predictive exposure models that estimate exposure from both the dermal and the inadvertent ingestion pathways. For exposure by these pathways the efficiency of transfer of materials between compartments (for example from surfaces to hands, or from hands to the mouth) are important determinants of exposure. A database of transfer efficiency data relevant for dermal and inadvertent ingestion exposure was developed, containing 534 empirically measured transfer efficiencies measured between 1980 and 2010 and reported in the peer-reviewed and grey literature. The majority of the reported transfer efficiencies (84%) relate to transfer between surfaces and hands, but the database also includes efficiencies for other transfer scenarios, including surface-to-glove, hand-to-mouth, and skin-to-skin. While the conceptual model can provide a framework for a predictive exposure assessment model, the database provides detailed information on transfer efficiencies between the various compartments. Together, the conceptual model and the database provide a basis for the development of a quantitative tool to estimate inadvertent ingestion exposure in the workplace.

Participatory ergonomic intervention versus strength training on chronic pain and work disability in slaughterhouse workers: study protocol for a single-blind, randomized controlled trial

PubMed Central

2013-01-01

Background The prevalence of musculoskeletal pain in the shoulder, arm and hand is high among slaughterhouse workers, allegedly due to the highly repetitive and forceful exposure of these body regions during work. Work disability is a common consequence of these pains. Lowering the physical exposure through ergonomics intervention is the traditional strategy to reduce the workload. An alternative strategy could be to increase physical capacity of the worker through strength training. This study investigates the effect of two contrasting interventions, participatory ergonomics versus strength training on pain and work disability in slaughterhouse workers with chronic pain. Methods/design 66 slaughterhouse workers were allocated to 10 weeks of (1) strength training of the shoulder, arm and hand muscles for 3 x 10 minutes per week, or (2) participatory ergonomics involving counseling on workstation adjustment and optimal use of work tools (~usual care control group). Inclusion criteria were (1) working at a slaughterhouse for at least 30 hours per week, (2) pain intensity in the shoulder, elbow/forearm, or hand/wrist of at least 3 on a 0–10 VAS scale during the last three months, (3) pain lasting for more than 3 months, (4) frequent pain (at least 3 days per week) (5) at least moderate work disability, (6) no strength training during the last year, (7) no ergonomics instruction during the last year. Perceived pain intensity (VAS scale 0–10) of the shoulder, elbow/forearm and hand/wrist (primary outcome) and Disability of the Arm, Shoulder and Hand (Work module, DASH questionnaire) were measured at baseline and 10-week follow-up. Further, total muscle tenderness score and muscle function were assessed during clinical examination at baseline and follow-up. Discussion This RCT study will provide experimental evidence of the effectiveness of contrasting work-site interventions aiming at reducing chronic pain and work disability among employees engaged in repetitive and forceful work. Trial registration ClinicalTrials.gov:NCT01671267 PMID:23433448

The effects of mothers' past infant-holding preferences on their adult children's face processing lateralisation.

PubMed

Vervloed, Mathijs P J; Hendriks, Angélique W; van den Eijnde, Esther

2011-04-01

Face processing development is negatively affected when infants have not been exposed to faces for some time because of congenital cataract blocking all vision (Le Grand, Mondloch, Maurer, & Brent, 2001). It is not clear, however, whether more subtle differences in face exposure may also have an influence. The present study looked at the effect of the mother's preferred side of holding an infant, on her adult child's face processing lateralisation. Adults with a mother who had a left-arm preference for holding infants were compared with adults with a mother who had a right-arm holding preference. All participants were right-handed and had been exclusively bottle-fed during infancy. The participants were presented with two chimeric faces tests, one involving emotion and the other one gender. The left-arm held individuals showed a normal left-bias on the chimeric face tests, whereas the right-arm held individuals a significantly decreased left-bias. The results might suggest that reduced exposure to high quality emotional information on faces in infancy results in diminished right-hemisphere lateralisation for face processing. Copyright © 2011 Elsevier Inc. All rights reserved.

Evaluation of a functional hand orthosis combined with electrical stimulation adjunct to arm-hand rehabilitation in subacute stroke patients with a severely to moderately affected hand function.

PubMed

Franck, Johan Anton; Smeets, Rob Johannes Elise Marie; Seelen, Henk Alexander Maria

2018-01-09

To investigate the usability and effectiveness of a functional hand orthosis, combined with electrical stimulation adjunct to therapy-as-usual, on functional use of the moderately/severely impaired hand in sub-acute stroke patients. Single case experiment (A-B-A'-design) involving eight sub-acute stroke patients. The functional hand orthosis and electrical stimulation were used for six weeks, four days/week, 45'/day. Action_Research_Arm_Test, Intrinsic_Motivation_Inventory. At group level, patients improved 19.2 points (median value) (interquartile range: [8.8, 29.5] points) on the Action_Research_Arm_Test (p = 0.001). After correcting for spontaneous recovery and/or therapy-as-usual effects Action_Research_Arm_Test scores still improved significantly (median: 17.2 points; interquartile range: [5.1, 29.2] points) (p = 0.002). At individual level, six patients had improved as to arm-hand skill performance at follow-up (p < = 0.010). In one patient, arm-hand skill performance improvement did not attain statistical significance. In another patient, no arm-hand skill performance improvement was observed. Average Intrinsic_Motivation_Inventory sub-scores were between 4.6 and 6.3 (maximum: 7), except for 'perceived pressure/tension' (3.3). Sub-acute stroke patients who display only little/modest improvement on their capacity to perform daily activities, seem to benefit from training with a dynamic arm orthosis in combination with electrical stimulation. Patients' perceived intrinsic motivation and sense of self-regulation was high. Implications for rehabilitation Arm-hand training featuring the dynamic hand orthosis in combination with electrical stimulation shows a shift from no dexterity to dexterity. As to the users' experience regarding the dynamic hand orthosis, patients perceive a high-intrinsic motivation and sense of self-regulation. Combining the orthosis with electrical stimulation creates opportunities for a nonfunctional hand towards task-oriented training.

Children Learning About Second-Hand Smoking: A Feasibility Cluster Randomized Controlled Trial.

PubMed

Huque, Rumana; Dogar, Omara; Cameron, Ian; Thomson, Heather; Amos, Amanda; Siddiqi, Kamran

2015-12-01

Exposure to second-hand smoke is a threat to children's health. We developed a school-based smoke-free intervention (SFI) to support families in implementing smoke-free homes in Bangladesh, and gathered preliminary evidence of its effectiveness. A feasibility cluster randomized controlled trial of SFI was conducted in 24 schools in Mirpur, an urban area within Dhaka. Using simple stratified randomization, schools were allocated to: Arm A (SFI only), Arm B (SFI plus reminders), and Arm C (the control group). A total of 781 year-5 children (10-12 years old) in the consenting schools, participated in the study. Outcomes including "smoke-free homes" and "social visibility" that is, not smoking in front of children at home were assessed through questionnaire-based children's surveys, administered by researchers, at baseline and at weeks 1, 12, 27, and 52 in all arms. "Smoke-free homes" were significantly higher in Arm A (odds ratio [OR] = 4.8; 95% CI = 2.6-9.0) and in Arm B (OR = 3.9; 95% CI = 2.0-7.5) than in Arm C, when controlled for the baseline levels, at year 1. Similarly, "social visibility" was significantly reduced in Arm A (OR = 5.8; 95% CI = 2.8-11.7) and in Arm B (OR = 7.2; 95% CI = 3.3-15.9) than Arm C, when controlled for the baseline levels, at year 1. We observed an increasing trend (Cochrane Armitage test statistic [Z] = 3.8; p < .0001) in homes becoming smoke-free with increasing intensity of the intervention (control < Arm A < Arm B), and a decreasing trend (Z = -5.13; p < .0001) in social visibility at homes. SFI has the potential to encourage children to negotiate a smoke-free environment in their homes. © The Author 2015. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Factors affecting the perception of whole-body vibration of occupational drivers: an analysis of posture and manual materials handling and musculoskeletal disorders

PubMed Central

Raffler, Nastaran; Ellegast, Rolf; Kraus, Thomas; Ochsmann, Elke

2016-01-01

Due to the high cost of conducting field measurements, questionnaires are usually preferred for the assessment of physical workloads and musculoskeletal disorders (MSDs). This study compares the physical workloads of whole-body vibration (WBV) and awkward postures by direct field measurements and self-reported data of 45 occupational drivers. Manual materials handling (MMH) and MSDs were also investigated to analyse their effect on drivers' perception. Although the measured values for WBV exposure were very similarly distributed among the drivers, the subjects' perception differed significantly. Concerning posture, subjects seemed to estimate much better when the difference in exposure was significantly large. The percentage of measured awkward trunk and head inclination were significantly higher for WBV-overestimating subjects than non-overestimators; 77 and 80% vs. 36 and 33%. Health complaints in terms of thoracic spine, cervical spine and shoulder–arm were also significantly more reported by WBV-overestimating subjects (42, 67, 50% vs. 0, 25, 13%, respectively). Although more MMH was reported by WBV-overestimating subjects, there was no statistical significance in this study. PMID:26114619

Intra‐Target Microdosing – A Novel Drug Development Approach: Proof of Concept, Safety, and Feasibility Study in Humans

PubMed Central

MacLeod, D; Lee, K; Santoro, A; DeMasi, DK; Hawk, T; Feinglos, M; Rowland, M; Noveck, RJ

2017-01-01

Abstract Intra‐Target Microdosing (ITM) is a novel drug development approach aimed at increasing the efficiency of first‐in‐human (FIH) testing of new molecular entities (NMEs). ITM combines intra‐target drug delivery and “microdosing,” the subpharmacological systemic exposure. We hypothesized that when the target tissue is small (about 1/100th of total body mass), ITM can lead to target therapeutic‐level exposure with minimal (microdose) systemic exposure. Each of five healthy male volunteers received insulin microdose into the radial artery or full therapeutic dose intravenously in separate visits. Insulin and glucose levels were similar between systemic administration and ITM administration in the ipsilateral hand, and glucose levels demonstrated a reduction in the ipsilateral hand but not in the contralateral hand. Positron emission tomography (PET) imaging of 18F‐fluorodeoxyglucose (FDG) uptake demonstrated differences between the ipsilateral and contralateral arms. The procedures were safe and well‐tolerated. Results are consistent with ITM proof‐of‐concept (POC) and demonstrate the ethical, regulatory, and logistical feasibility of the approach. PMID:28689370

Software-recorded and self-reported duration of computer use in relation to the onset of severe arm-wrist-hand pain and neck-shoulder pain.

PubMed

Ijmker, Stefan; Huysmans, Maaike A; van der Beek, Allard J; Knol, Dirk L; van Mechelen, Willem; Bongers, Paulien M; Blatter, Birgitte M

2011-07-01

In both science and media, the adverse effects of a long duration of computer use at work on musculoskeletal health have long been debated. Until recently, the duration of computer use was mainly measured by self-reports, and studies using more objective measures, such as software-recorded computer duration, were lacking. The objective of this study was to examine the association between duration of computer use at work, measured with software and self-reports, and the onset of severe arm-wrist-hand and neck-shoulder symptoms. A 2-year follow-up study was conducted between 2004 and 2006 among 1951 office workers in The Netherlands. Self-reported computer duration and other risk factors were collected at baseline and at 1-year follow-up. Computer use at work was recorded continuously with computer software for 1009 participants. Outcome questionnaires were obtained at baseline and every 3 months during follow-up. Cases were identified based on the transition within 3 months of no or minor symptoms to severe symptoms. Self-reported duration of computer use was positively associated with the onset of both arm-wrist-hand (RR 1.9, 95% CI 1.1 to 3.1 for more than 4 h/day of total computer use at work) and neck-shoulder symptoms (RR 1.5, 95% CI 1.1 to 2.0 for more than 4 h/day of mouse use at work). The recorded duration of computer use did not show any statistically significant association with the outcomes. In the present study, no association was found between the software-recorded duration of computer use at work and the onset of severe arm-wrist-hand and neck-shoulder symptoms using an exposure window of 3 months. In contrast, a positive association was found between the self-reported duration of computer use at work and the onset of severe arm-wrist-hand and neck-shoulder symptoms. The different findings for recorded and self-reported computer duration could not be explained satisfactorily.

Effects of training with a passive hand orthosis and games at home in chronic stroke: a pilot randomised controlled trial.

PubMed

Nijenhuis, Sharon M; Prange-Lasonder, Gerdienke B; Stienen, Arno Ha; Rietman, Johan S; Buurke, Jaap H

2017-02-01

To compare user acceptance and arm and hand function changes after technology-supported training at home with conventional exercises in chronic stroke. Secondly, to investigate the relation between training duration and clinical changes. A randomised controlled trial. Training at home, evaluation at research institute. Twenty chronic stroke patients with severely to mildly impaired arm and hand function. Participants were randomly assigned to six weeks (30 minutes per day, six days a week) of self-administered home-based arm and hand training using either a passive dynamic wrist and hand orthosis combined with computerised gaming exercises (experimental group) or prescribed conventional exercises from an exercise book (control group). Main outcome measures are the training duration for user acceptance and the Action Research Arm Test for arm and hand function. Secondary outcomes are the Intrinsic Motivation Inventory, Fugl-Meyer assessment, Motor Activity Log, Stroke Impact Scale and grip strength. The control group reported a higher training duration (189 versus 118 minutes per week, P = 0.025). Perceived motivation was positive and equal between groups ( P = 0.935). No differences in clinical outcomes over training between groups were found (P ⩾ 0.165). Changes in Box and Block Test correlated positively with training duration ( P = 0.001). Both interventions were accepted. An additional benefit of technology-supported arm and hand training over conventional arm and hand exercises at home was not demonstrated. Training duration in itself is a major contributor to arm and hand function improvements.

Wearable Sensing of Cardiac Timing Intervals from Cardiogenic Limb Vibration Signals

PubMed Central

Wiens, Andrew D.; Johnson, Ann; Inan, Omer T.

2017-01-01

In this paper we describe a new method to measure aortic valve opening (AVO) and closing (AVC) from cardiogenic limb vibrations (i.e., wearable ballistocardiogram [BCG] signals). AVO and AVC were detected for each heartbeat with accelerometers on the upper arm (A), wrist (W), and knee (K) of 22 subjects following isometric exercise. Exercise-induced changes were recorded with impedance cardiography. The method, Filter BCG, detects peaks in distal vibrations after filtering with individually-tuned bandpass filters. In agreement with recent studies, we did not find peaks at AVO and AVC in limb vibrations directly. Interestingly, distal vibrations filtered with FilterBCG yielded reliable peaks at AVO (r2 = 0.95 A, 0.94 W, 0.77 K) and AVC (r2= 0.92 A, 0.89 W, 0.68 K). FilterBCG measures AVO and AVC accurately from arm, wrist, and knee vibrations, and it outperforms the standard R-J interval method. PMID:29123459

Does Muscular Force of the Upper Body Increase Following Acute, Direct Vibration?

PubMed

Cochrane, D J

2016-06-01

The aim of the current study was to examine the acute effect of direct vibration has on bicep curl force-generating capacity. 11 healthy team and individual sport-trained males performed right and left DB bicep curl at 50% of 1 RM where peak force (PF), mean force (MF), rate of force development (RFD) and electromyography (EMG) were assessed during the concentric phase before and immediately after direct vibration. Using new vibration technology utilizing a pulsing frequency (0-170 Hz) each arm was randomly assigned to receive either 10 min of direct vibration or control (no vibration). Following direct vibration PF increased 6.6±4.5 N (difference pre-post±90 CL; p>0.05) compared to control FP (-1.2±65 N; p>0.05) however, this was not significant. Furthermore, there were no other significant changes (p>0.05) in MP, RFD and EMG between vibration and control arms. This is in agreement with other research that has reported that acute strength changes from vibration elicits negligible changes, however it appears that there are no detrimental effects of using this new vibration device. © Georg Thieme Verlag KG Stuttgart · New York.

Return to Flying Duties Following Centrifuge or Vibration Exposures

NASA Technical Reports Server (NTRS)

Scheuring, Richard A.; Clarke, Jonathan; Jones, Jeffrey A.

2009-01-01

Introduction: In an effort to determine the human performance limits for vibration in spacecraft being developed by NASA, astronauts were evaluated during a simulated launch profile in a centrifuge/vibration environment and separate vibration-only simulation. Current USAF and Army standards for return to flight following centrifuge exposures require 12-24 hours to pass before a crewmember may return to flying duties. There are no standards on vibration exposures and return to flying duties. Based on direct observation and provocative neurological testing of the astronauts, a new standard for return to flying duties following centrifuge and/or vibration exposures was established. Methods: 13 astronaut participants were exposed to simulated launch profiles in a + 3.5 Gx bias centrifuge/vibration environment and separately on a vibration table at the NASA-Ames Research Center. Each subject had complete neurological evaluations pre- and post-exposure for the centrifuge/vibration runs with the NASA neurological function rating scale (NFRS). Subjects who participated in the vibration-only exposures had video oculography performed with provocative maneuvers in addition to the NFRS. NFRS evaluations occurred immediately following each exposure and at 1 hour post-run. Astronauts who remained symptomatic at 1 hour had repeat NFRS performed at 1 hour intervals until the crewmember was asymptomatic. Results: Astronauts in the centrifuge/vibration study averaged a 3-5 point increase in NFRS scores immediately following exposure but returned to baseline 3 hours post-run. Subjects exposed to the vibration-only simulation had a 1-3 point increase following exposure and returned to baseline within 1-2 hours. Pre- and post- vibration exposure video oculography did not reveal any persistent ocular findings with provocative testing 1 hour post-exposure. Discussion: Based on direct observations and objective measurement of neurological function in astronauts following simulated launch profiles, asymptomatic individuals are allowed to return to flying duties within 3 hours following centrifuge/vibration and 2 hours after vibration-only exposures.

[Differences in the prevalence of work related disorders among construction workers between the end of 90s and 2006].

PubMed

Riva, M M; Pavesi, G; Bartolozzi, F; Bancone, C; Mosconi, G

2007-01-01

The aim of this work is to analyse the prevalence of occupational diseases in construction industry, comparing the results of the first years of health surveillance (1996-2000) and today's situation. We compare the prevalence of occupational diseases observed in 1348 workers during the period 1996-2000 (mean age 36,4 years, DS 11,8; mean experience in construction industry 16,9 years, DS 12,3) and the one observed in 795 different workers during 2006 (mean age 38,8 years, DS 11,1; mean experience in construction industry 18 years, DS 16,6). The prevalence of occupational diseases is respectively 12.09% and 12.83%. But analysing the single pathology it's possible to observe important differences between the two groups. In the workers observed in 2006 there is a significant reduction in prevalence of hearing loss caused by chronic exposure to noise and in prevalence of vascular disease caused by hand-arm vibrations: respectively from 94,9 to 79,2 cases/1000 workers and from 6,7 to 2.6 cases/1000 workers. Musculoskeletal diseases instead are increased from 11,1 to 37,7 cases/1000 workers, showing more attention to the problem, better diagnostics ability and more recognition by public insurance agency for occupational diseases.

Predicting hand function in older adults: evaluations of grip strength, arm curl strength, and manual dexterity.

PubMed

Liu, Chiung-Ju; Marie, Deana; Fredrick, Aaron; Bertram, Jessica; Utley, Kristen; Fess, Elaine Ewing

2017-08-01

Hand function is critical for independence in activities of daily living for older adults. The purpose of this study was to examine how grip strength, arm curl strength, and manual dexterous coordination contributed to time-based versus self-report assessment of hand function in community-dwelling older adults. Adults aged ≥60 years without low vision or neurological disorders were recruited. Purdue Pegboard Test, Jamar hand dynamometer, 30-second arm curl test, Jebsen-Taylor Hand Function Test, and the Late-Life Function and Disability Instrument were administered to assess manual dexterous coordination, grip strength, arm curl strength, time-based hand function, and self-report of hand function, respectively. Eighty-four adults (mean age = 72 years) completed the study. Hierarchical multiple regressions show that older adults with better arm curl strength (β = -.25, p < .01) and manual dexterous coordination (β = -.52, p < .01) performed better on the time-based hand function test. In comparison, older adults with better grip strength (β = .40, p < .01), arm curl strength (β = .23, p < .05), and manual dexterous coordination (β = .23, p < .05) were associated with better self-report of upper extremity function. The relationship between grip strength and hand function may be test-specific. Grip strength becomes a significant factor when the test requires grip strength to successfully complete the test tasks. Arm curl strength independently contributed to hand function in both time-based and self-report assessments, indicating that strength of extrinsic muscles of the hand are essential for hand function.

Exposure of the surgeon's hands to radiation during hand surgery procedures.

PubMed

Żyluk, Andrzej; Puchalski, Piotr; Szlosser, Zbigniew; Dec, Paweł; Chrąchol, Joanna

2014-01-01

The objective of the study was to assess the time of exposure of the surgeon's hands to radiation and calculate of the equivalent dose absorbed during surgery of hand and wrist fractures with C-arm fluoroscope guidance. The necessary data specified by the objective of the study were acquired from operations of 287 patients with fractures of fingers, metacarpals, wrist bones and distal radius. 218 operations (78%) were percutaneous procedures and 60 (22%) were performed by open method. Data on the time of exposure and dose of radiation were acquired from the display of the fluoroscope, where they were automatically generated. These data were assigned to the individual patient, type of fracture, method of surgery and the operating surgeon. Fixations of distal radial fractures required longer times of radiation exposure (mean 61 sec.) than fractures of the wrist/metacarpals and fingers (38 and 32 sec., respectively), which was associated with absorption of significantly higher equivalent doses. Fixations of distal radial fractures by open method were associated with statistically significantly higher equivalent doses (0.41 mSv) than percutaneous procedures (0.3 mSv). Fixations of wrist and metacarpal bone fractures by open method were associated with lower equivalent doses (0.34 mSv) than percutaneous procedures (0.37 mSv),but the difference was not significant. Fixations of finger fractures by open method were associated with lower equivalent doses (0.13 mSv) than percutaneous procedures (0.24 mSv), the difference being statistically non-significant. Statistically significant differences in exposure time and equivalent doses were noted between 4 surgeons participating in the study, but no definitive relationship was found between these parameters and surgeons' employment time. 1. Hand surgery procedures under fluoroscopic guidance are associated with mild exposure of the surgeons' hands to radiation. 2. The equivalent dose was related to the type of fracture, operative technique and - to some degree - to the time of employment of the surgeon.

Upper-limb prosthetic control using wearable multichannel mechanomyography.

PubMed

Wilson, Samuel; Vaidyanathan, Ravi

2017-07-01

In this paper we introduce a robust multi-channel wearable sensor system for capturing user intent to control robotic hands. The interface is based on a fusion of inertial measurement and mechanomyography (MMG), which measures the vibrations of muscle fibres during motion. MMG is immune to issues such as sweat, skin impedance, and the need for a reference signal that is common to electromyography (EMG). The main contributions of this work are: 1) the hardware design of a fused inertial and MMG measurement system that can be worn on the arm, 2) a unified algorithm for detection, segmentation, and classification of muscle movement corresponding to hand gestures, and 3) experiments demonstrating the real-time control of a commercial prosthetic hand (Bebionic Version 2). Results show recognition of seven gestures, achieving an offline classification accuracy of 83.5% performed on five healthy subjects and one transradial amputee. The gesture recognition was then tested in real time on subsets of two and five gestures, with an average accuracy of 93.3% and 62.2% respectively. To our knowledge this is the first applied MMG based control system for practical prosthetic control.

An improved method for the calculation of Near-Field Acoustic Radiation Modes

NASA Astrophysics Data System (ADS)

Liu, Zu-Bin; Maury, Cédric

2016-02-01

Sensing and controlling Acoustic Radiation Modes (ARMs) in the near-field of vibrating structures is of great interest for broadband noise reduction or enhancement, as ARMs are velocity distributions defined over a vibrating surface, that independently and optimally contribute to the acoustic power in the acoustic field. But present methods only provide far-field ARMs (FFARMs) that are inadequate for the acoustic near-field problem. The Near-Field Acoustic Radiation Modes (NFARMs) are firstly studied with an improved numerical method, the Pressure-Velocity method, which rely on the eigen decomposition of the acoustic transfers between the vibrating source and a conformal observation surface, including sound pressure and velocity transfer matrices. The active and reactive parts of the sound power are separated and lead to the active and reactive ARMs. NFARMs are studied for a 2D baffled beam and for a 3D baffled plate, and so as differences between the NFARMS and the classical FFARMs. Comparisons of the NFARMs are analyzed when varying frequency and observation distance to the source. It is found that the efficiencies and shapes of the optimal active ARMs are independent on the distance while that of the reactive ones are distinctly related on.

What is the most effective posture to conduct vibration from the lower to the upper extremities during whole-body vibration exercise?

PubMed Central

Tsukahara, Yuka; Iwamoto, Jun; Iwashita, Kosui; Shinjo, Takuma; Azuma, Koichiro; Matsumoto, Hideo

2016-01-01

Background Whole-body vibration (WBV) exercise is widely used for training and rehabilitation. However, the optimal posture for training both the upper and lower extremities simultaneously remains to be established. Objectives The objective of this study was to search for an effective posture to conduct vibration from the lower to the upper extremities while performing WBV exercises without any adverse effects. Methods Twelve healthy volunteers (age: 22–34 years) were enrolled in the study. To measure the magnitude of vibration, four accelerometers were attached to the upper arm, back, thigh, and calf of each subject. Vibrations were produced using a WBV platform (Galileo 900) with an amplitude of 4 mm at two frequencies, 15 and 30 Hz. The following three postures were examined: posture A, standing posture with the knees flexed at 30°; posture B, crouching position with no direct contact between the knees and elbows; and posture C, crouching position with direct contact between the knees and elbows. The ratio of the magnitude of vibration at the thigh, back, and upper arm relative to that at the calf was used as an index of vibration conduction. Results Posture B was associated with a greater magnitude of vibration to the calf than posture A at 15 Hz, and postures B and C were associated with greater magnitudes of vibration than posture A at 30 Hz. Posture C was associated with a vibration conduction to the upper arm that was 4.62 times and 8.26 times greater than that for posture A at 15 and 30 Hz, respectively. Conclusion This study revealed that a crouching position on a WBV platform with direct contact between the knees and elbows was effective for conducting vibration from the lower to the upper extremities. PMID:26793008

Ultra-low frequency vertical vibration isolator based on LaCoste spring linkage.

PubMed

Li, G; Hu, H; Wu, K; Wang, G; Wang, L J

2014-10-01

For the applications in precision measurement such as absolute gravimeter, we have designed and built an ultra-low frequency vertical vibration isolator based on LaCoste spring linkage. In the system, an arm with test mass is suspended by a mechanical extension spring, and one end of the arm is connected to the frame with flexible pivots. The displacement of the arm is detected by an optical reflection method. With the displacement signal, a feedback control force is exerted on the arm to keep it at the balance position. This method can also correct the systematic drift caused by temperature change. In order to study the vibration isolation performance of the system, we analyze the dynamic characteristics of the spring linkage in the general case, and present key methods to adjust the natural oscillating period of the system. With careful adjustment, the system can achieve a steady oscillation with a natural period up to 32 s. This isolator has been tested based on the T-1 absolute gravimeter. A statistical uncertainty of 2 μGal has been achieved within a typical 12 h measurement. The experimental results verify that the isolator has significant vibration isolation performance, and it is very suitable for applications in high precision absolute gravity measurement.

Ultra-low frequency vertical vibration isolator based on LaCoste spring linkage

NASA Astrophysics Data System (ADS)

Li, G.; Hu, H.; Wu, K.; Wang, G.; Wang, L. J.

2014-10-01

For the applications in precision measurement such as absolute gravimeter, we have designed and built an ultra-low frequency vertical vibration isolator based on LaCoste spring linkage. In the system, an arm with test mass is suspended by a mechanical extension spring, and one end of the arm is connected to the frame with flexible pivots. The displacement of the arm is detected by an optical reflection method. With the displacement signal, a feedback control force is exerted on the arm to keep it at the balance position. This method can also correct the systematic drift caused by temperature change. In order to study the vibration isolation performance of the system, we analyze the dynamic characteristics of the spring linkage in the general case, and present key methods to adjust the natural oscillating period of the system. With careful adjustment, the system can achieve a steady oscillation with a natural period up to 32 s. This isolator has been tested based on the T-1 absolute gravimeter. A statistical uncertainty of 2 μGal has been achieved within a typical 12 h measurement. The experimental results verify that the isolator has significant vibration isolation performance, and it is very suitable for applications in high precision absolute gravity measurement.

Improved accuracy of screw implantation could decrease the incidence of post-operative hydrothorax? O-arm navigation vs. free-hand in thoracic spinal deformity correction surgery.

PubMed

Zhao, Zhihui; Liu, Zhen; Hu, Zongshan; Tseng, Changchun; Li, Jie; Pan, Wei; Qiu, Yong; Zhu, Zezhang

2018-03-16

The purpose of this study was to analyze the occurrence of PE after intra-operative O-arm navigation-assisted surgery and determine whether the post-operative PE incidence could be decreased by using O-arm navigation as compared to conventional free-hand technique. A cohort of 27 patients with spinal deformity who were operated upon with an O-arm navigated system (group A) between 2013 and 2016 were enrolled in the study. A total of 27 curve-matched patients treated by conventional free-hand technique were included as the control group (group B). Whole spine posterior-anterior and lateral radiographs, and CT scans were taken pre and post-operation. Radiologic parameters and volume of PE were measured and compared between the two groups. There were no significant differences in age, Cobb angle, and sagittal contour between the two groups pre-operatively. The mean total volume of post-operative PE was significantly larger in the free-hand group (p < 0.001). In the O-arm group, 59 malpositioned screws were identified in 22 patients. In the free-hand group, 88 malpositioned screws were found among 26 patients. The screw perforation rate was higher in the free-hand group than in the O-arm group (p = 0.007). In the O-arm group, the mean volume of PE was significantly larger among patients with malpositioned screws than those without malpositioned screws (p < 0.001), as well as in the free-hand group. The volume of PE after correction surgery can be significantly decreased by application of O-arm navigation system as compared to conventional free-hand technique. We ascribed the improvement to the accuracy of screw implantation navigated by O-arm.

Lower Arm Muscle Activation during Indirect-Localized Vibration: The Influence of Skill Levels When Applying Different Acceleration Loads.

PubMed

Padulo, Johnny; Di Giminiani, Riccardo; Dello Iacono, Antonio; Zagatto, Alessandro M; Migliaccio, Gian M; Grgantov, Zoran; Ardigò, Luca P

2016-01-01

We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads.

Lower Arm Muscle Activation during Indirect-Localized Vibration: The Influence of Skill Levels When Applying Different Acceleration Loads

PubMed Central

Padulo, Johnny; Di Giminiani, Riccardo; Dello Iacono, Antonio; Zagatto, Alessandro M.; Migliaccio, Gian M.; Grgantov, Zoran; Ardigò, Luca P.

2016-01-01

We investigated the electromyographic response to synchronous indirect-localized vibration interventions in international and national table tennis players. Twenty-six male table tennis players, in a standing position, underwent firstly an upper arms maximal voluntary contraction and thereafter two different 30-s vibration interventions in random order: high acceleration load (peak acceleration = 12.8 g, frequency = 40 Hz; peak-to-peak displacement = 4.0 mm), and low acceleration load (peak acceleration = 7.2 g, frequency = 30 Hz, peak-to-peak displacement = 4.0 mm). Surface electromyography root mean square from brachioradialis, extensor digitorum, flexor carpi radialis, and flexor digitorum superficialis recorded during the two vibration interventions was normalized to the maximal voluntary contraction recording. Normalized surface electromyography root mean square was higher in international table tennis players with respect to national ones in all the interactions between muscles and vibration conditions (P < 0.05), with the exception of flexor carpi radialis (at low acceleration load, P > 0.05). The difference in normalized surface electromyography root mean square between international table tennis players and national ones increased in all the muscles with high acceleration load (P < 0.05), with the exception of flexor digitorum superficialis (P > 0.05). The muscle activation during indirect-localized vibration seems to be both skill level and muscle dependent. These results can optimize the training intervention in table tennis players when applying indirect-localized vibration to lower arm muscles. Future investigations should discriminate between middle- and long-term adaptations in response to specific vibration loads. PMID:27378948

Blood pressure differences between arms and association of dominant hands with blood pressure differences and carotid atherosclerosis.

PubMed

Maeda, Shinji

2013-06-01

Guidelines for the management of hypertension recommend that blood pressure (BP) should be measured twice at every visit; it should be measured in both arms at the first visit, and the right arm BP or higher BP should be recorded. Manufacturers of home BP monitors tend to design the device for measurement of left arm BP. The arm preferred for BP measurement differs according to the methods recommended by the society and according to the home BP monitors. The BP difference (ΔBP) is calculated by subtracting left arm BP from right arm BP. Here, we aim to first investigate which hand will give the most accurate reading by a sphygmomanometer in daily medical practice. Second, we wish to assess the association of the dominant hand with absolute BP difference (|ΔBP|) of at least 10 mmHg and with early atherosclerotic markers in a subanalysis. We found that 6.4% of outpatients were left handed, and the percentage of individuals with systolic |ΔBP| (|ΔSBP|) and diastolic |ΔBP| (|ΔDBP|) of at least 10 mmHg was 14.4 and 7.2%, respectively. The dominant hand was not significantly associated with |ΔBP| of at least 10 mmHg or early atherosclerotic markers. This study suggests that BP measured in one arm is substitutable with that of the other arm because of a lack of association of |ΔBP| with the dominant hand. However, BP of both arms should be actively measured in new outpatients with moderate fever, lifestyle-related diseases, vascular events, age 65 years and above, and smoking history, all of which are factors potentially associated with |ΔBP| of at least 10 mmHg, regardless of the dominant hand.

System transmits mechanical vibration into hazardous environment

NASA Technical Reports Server (NTRS)

Armstrong, D. G.; Gaal, A. E.

1965-01-01

Vibration transducers are tested in a hazardous environment using a single axis transmission system with an electromagnetic shaker table and vibrating wires which drive identical rocker arms, one in the test cell and the other outside. This system can be modified for a multiaxis configuration.

Topographic analysis of the skull vibration-induced nystagmus test with piezoelectric accelerometers and force sensors.

PubMed

Dumas, Georges; Lion, Alexis; Perrin, Philippe; Ouedraogo, Evariste; Schmerber, Sébastien

2016-03-23

Vibration-induced nystagmus is elicited by skull or posterior cervical muscle stimulations in patients with vestibular diseases. Skull vibrations delivered by the skull vibration-induced nystagmus test are known to stimulate the inner ear structures directly. This study aimed to measure the vibration transfer at different cranium locations and posterior cervical regions to contribute toward stimulus topographic optimization (experiment 1) and to determine the force applied on the skull with a hand-held vibrator to study the test reproducibility and provide recommendations for good clinical practices (experiment 2). In experiment 1, a 100 Hz hand-held vibrator was applied on the skull (vertex, mastoids) and posterior cervical muscles in 11 healthy participants. Vibration transfer was measured by piezoelectric sensors. In experiment 2, the vibrator was applied 30 times by two experimenters with dominant and nondominant hands on a mannequin equipped to measure the force. Experiment 1 showed that after unilateral mastoid vibratory stimulation, the signal transfer was higher when recorded on the contralateral mastoid than on the vertex or posterior cervical muscles (P<0.001). No difference was observed between the different vibratory locations when vibration transfer was measured on vertex and posterior cervical muscles. Experiment 2 showed that the force applied to the mannequin varied according to the experimenters and the handedness, higher forces being observed with the most experienced experimenter and with the dominant hand (10.3 ± 1.0 and 7.8 ± 2.9 N, respectively). The variation ranged from 9.8 to 29.4% within the same experimenter. Bone transcranial vibration transfer is more efficient from one mastoid to the other mastoid than other anatomical sites. The mastoid is therefore the optimal site for skull vibration-induced nystagmus test in patients with unilateral vestibular lesions and enables a stronger stimulation of the healthy side. In clinical practice, the vibrator should be placed on the mastoid and should be held by the clinician's dominant hand.

Transmission of vibration through gloves: effects of material thickness.

PubMed

Md Rezali, Khairil Anas; Griffin, Michael J

2016-08-01

It might be assumed that increasing the thickness of a glove would reduce the vibration transmitted to the hand. Three material samples from an anti-vibration glove were stacked to produce three thicknesses: 6.4, 12.8 and 19.2 mm. The dynamic stiffnesses of all three thicknesses, the apparent mass at the palm and the finger and the transmission of vibration to the palm and finger were measured. At frequencies from 20 to 350 Hz, the material reduced vibration at the palm but increased vibration at the finger. Increased thickness reduced vibration at the palm but increased vibration at the finger. The measured transmissibilities could be predicted from the material dynamic stiffness and the apparent mass of the palm and finger. Reducing the dynamic stiffness of glove material may increase or decrease the transmission of vibration, depending on the material, the frequency of vibration and the location of measurement (palm or finger). Practitioner Summary: Transmission of vibration through gloves depends on the dynamic response of the hand and the dynamic stiffness of glove material, which depends on material thickness. Measuring the transmission of vibration through gloves to the palm of the hand gives a misleading indication of the transmission of vibration to the fingers.

Modal Parameter Identification of a Flexible Arm System

NASA Technical Reports Server (NTRS)

Barrington, Jason; Lew, Jiann-Shiun; Korbieh, Edward; Wade, Montanez; Tantaris, Richard

1998-01-01

In this paper an experiment is designed for the modal parameter identification of a flexible arm system. This experiment uses a function generator to provide input signal and an oscilloscope to save input and output response data. For each vibrational mode, many sets of sine-wave inputs with frequencies close to the natural frequency of the arm system are used to excite the vibration of this mode. Then a least-squares technique is used to analyze the experimental input/output data to obtain the identified parameters for this mode. The identified results are compared with the analytical model obtained by applying finite element analysis.

Instrumentation for measuring dynamic spinal load moment exposures in the workplace.

PubMed

Marras, William S; Lavender, Steven A; Ferguson, Sue A; Splittstoesser, Riley E; Yang, Gang; Schabo, Pete

2010-02-01

Prior research has shown the load moment exposure to be one of the strongest predictors of low back disorder risk in manufacturing jobs. However, to extend these finding to the manual lifting and handling of materials in distribution centers, where the layout of the lifting task changes from one lift to the next and the lifts are highly dynamic, would be very challenging without an automated means of quantifying reach distances and item weights. The purpose of this paper is to describe the development and validation of automated instrumentation, the Moment Exposure Tracking System (METS), designed to capture the dynamic load moment exposures and spine postures used in distribution center jobs. This multiphase process started by obtaining baseline data describing the accuracy of existing manual methods for obtaining moment arms during the observation of dynamic lifting for the purposes of benchmarking the automated system. The process continued with the development and calibration of an ultrasonic system to track hand location and the development of load sensing handles that could be used to assess item weights. The final version of the system yielded an average absolute error in the load's moment arm of 4.1cm under the conditions of trunk flexion and load asymmetry. This compares well with the average absolute error of 10.9cm obtained using manual methods of measuring moment arms. With the item mass estimates being within half a kilogram, the instrumentation provides a reliable and valid means for assessing dynamic load moment exposures in dynamic distribution center lifting tasks.

Radiation exposure and safety practices during pediatric central line placement

PubMed Central

Saeman, Melody R.; Burkhalter, Lorrie S.; Blackburn, Timothy J.; Murphy, Joseph T.

2015-01-01

Purpose Pediatric surgeons routinely use fluoroscopy for central venous line (CVL) placement. We examined radiation safety practices and patient/surgeon exposure during fluoroscopic CVL. Methods Fluoroscopic CVL procedures performed by 11 pediatric surgeons in 2012 were reviewed. Fluoroscopic time (FT), patient exposure (mGy), and procedural data were collected. Anthropomorphic phantom simulations were used to calculate scatter and dose (mSv). Surgeons were surveyed regarding safety practices. Results 386 procedures were reviewed. Median FT was 12.8 seconds. Median patient estimated effective dose was 0.13 mSv. Median annual FT per surgeon was 15.4 minutes. Simulations showed no significant difference (p = 0.14) between reported exposures (median 3.5 mGy/min) and the modeled regression exposures from the C-arm default mode (median 3.4 mGy/min). Median calculated surgeon exposure was 1.5 mGy/year. Eight of 11 surgeons responded to the survey. Only three reported 100% lead protection and frequent dosimeter use. Conclusion We found non-standard radiation training, safety practices, and dose monitoring for the 11 surgeons. Based on simulations, the C-arm default setting was typically used instead of low dose. While most CVL procedures have low patient/surgeon doses, every effort should be used to minimize patient and occupational exposure, suggesting the need for formal hands-on training for non-radiologist providers using fluoroscopy. PMID:25837269

Informatics in radiology: use of a C-arm fluoroscopy simulator to support training in intraoperative radiography.

PubMed

Bott, Oliver Johannes; Dresing, Klaus; Wagner, Markus; Raab, Björn-Werner; Teistler, Michael

2011-01-01

Mobile image intensifier systems (C-arms) are used frequently in orthopedic and reconstructive surgery, especially in trauma and emergency settings, but image quality and radiation exposure levels may vary widely, depending on the extent of the C-arm operator's knowledge and experience. Current training programs consist mainly of theoretical instruction in C-arm operation, the physical foundations of radiography, and radiation avoidance, and are largely lacking in hands-on application. A computer-based simulation program such as that tested by the authors may be one way to improve the effectiveness of C-arm training. In computer simulations of various scenarios commonly encountered in the operating room, trainees using the virtX program interact with three-dimensional models to test their knowledge base and improve their skill levels. Radiographs showing the simulated patient anatomy and surgical implants are "reconstructed" from data computed on the basis of the trainee's positioning of models of a C-arm, patient, and table, and are displayed in real time on the desktop monitor. Trainee performance is signaled in real time by color graphics in several control panels and, on completion of the exercise, is compared in detail with the performance of an expert operator. Testing of this computer-based training program in continuing medical education courses for operating room personnel showed an improvement in the overall understanding of underlying principles of intraoperative radiography performed with a C-arm, with resultant higher image quality, lower overall radiation exposure, and greater time efficiency. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.313105125/-/DC1. Copyright © RSNA, 2011.

Whole-body vibration exposure in sport: four relevant cases.

PubMed

Tarabini, Marco; Saggin, Bortolino; Scaccabarozzi, Diego

2015-01-01

This study investigates the whole-body vibration exposure in kite surfing, alpine skiing, snowboarding and cycling. The vibration exposure was experimentally evaluated following the ISO 2631 guidelines. Results evidenced that the most critical axis is the vertical one. The weighted vibration levels are always larger than 2.5 m/s(2) and the vibration dose values are larger than 25 m/s(1.75). The exposure limit values of the EU directive are reached after 8-37 min depending on the sport. The vibration magnitude is influenced by the athletes' speed, by their skill level and sometimes by the equipment. The large vibration values suggest that the practice of sport activities may be a confounding factor in the aetiology of vibration-related diseases. The vibration exposure in some sports is expected to be large, but has never been quantified in the literature. Results of experiments performed in cycling, alpine and water sports outlined vibration levels exceeding the EU standard limit values.

Dexterous Humanoid Robotic Wrist

NASA Technical Reports Server (NTRS)

Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Reich, David M. (Inventor); Wampler, II, Charles W. (Inventor); Askew, Scott R. (Inventor); Diftler, Myron A. (Inventor); Nguyen, Vienny (Inventor)

2013-01-01

A humanoid robot includes a torso, a pair of arms, a neck, a head, a wrist joint assembly, and a control system. The arms and the neck movably extend from the torso. Each of the arms includes a lower arm and a hand that is rotatable relative to the lower arm. The wrist joint assembly is operatively defined between the lower arm and the hand. The wrist joint assembly includes a yaw axis and a pitch axis. The pitch axis is disposed in a spaced relationship to the yaw axis such that the axes are generally perpendicular. The pitch axis extends between the yaw axis and the lower arm. The hand is rotatable relative to the lower arm about each of the yaw axis and the pitch axis. The control system is configured for determining a yaw angle and a pitch angle of the wrist joint assembly.

Induction of uncoiled chromosomes by vibration.

PubMed

Delinassios, J G

1979-02-15

Chromatin condensation during metaphase can be removed by simple vibration of metaphase cells prior to fixation. Uncoiled chromosome arms consist of long threads with dense regions at irregular distances each from the other.

Moving Events in Time: Time-Referent Hand-Arm Movements Influence Perceived Temporal Distance to Past Events

ERIC Educational Resources Information Center

Blom, Stephanie S. A. H.; Semin, Gun R.

2013-01-01

We examine and find support for the hypothesis that time-referent hand-arm movements influence temporal judgments. In line with the concept of "left is associated with earlier times, and right is associated with later times," we show that performing left (right) hand-arm movements while thinking about a past event increases (decreases) the…

Impedance hand controllers for increasing efficiency in teleoperations

NASA Technical Reports Server (NTRS)

Carignan, C.; Tarrant, J.

1989-01-01

An impedance hand controller with direct force feedback is examined as an alternative to bilateral force reflection in teleoperations involving force contact. Experimentation revealed an operator preference for direct force feedback which provided a better feel of contact with the environment. The advantages of variable arm impedance were also made clear in tracking tests where subjects preferred the larger hand controller inertias made possible by the acceleration feedback loop in the master arm. The ability to decouple the hand controller impedance from the slave arm dynamics is expected to be even more significant when the inertial properties of various payloads in the slave arm are considered.

[Actual conditions of occupational health administration of small-scale enterprises in Japan: (II). Occupational health controls for hazardous and musculo-skeletally stressful working factors].

PubMed

Kumagai, S; Hirata, M; Tabuchi, T; Tainaka, H; Andoh, K; Oda, H

2000-09-01

In order to clarify the actual condition of occupational health management for hazardous and musculo-skeletally stressful work factors in small-scale enterprises (SSEs) in Japan, a questionnaire survey was conducted in an area near Osaka city. The hazardous work factors examined were dust, organic solvents, lead, specified chemical substances, anoxia, noise, hand-arm vibration, ionizing radiation, high and low temperatures, and high air pressure. The musculo-skeletally stressful work factors examined were VDT work, prolonged standing, unnatural postures, handling of heavy weights, and stress on neck, shoulders and arms. The number of SSEs that replied to the questionnaire was 765 (recovery rate: 69.3%). Enterprises with noise, dust, hand-arm vibration and organic solvents numbered 14.0%, 10.7%, 6.9% and 6.4%, respectively, and those with other hazardous factors numbered less than 3%. Special medical examinations and working environment measurements for hazardous factors were conducted in 0.0% to 26.7% and 0.0% to 13.3%, respectively, of the enterprises. Working environment controls were conducted in 0.0% to 40.2%. Enterprises with prolonged standing and VDT work, were 42.0% and 35.8%, whereas those with other stressful factors were approximately 30%. Special medical examinations for musculo-skeletally stressful factors were conducted in 3.0% to 5.1% of the enterprises, and work controls were conducted in 20.4% to 25.3%. Non execution of the special medical examinations and working environment measurements were mainly due to "lack of knowledge of the law (19.7% and 30.2%)" and "lack of time to perform (16.0% and 23.3%)". Non execution of the controls for the hazardous work factors was due to "lack of knowledge as to how to control (9.0%)", "high costs (7.4%)", "lack of time to perform (6.4%)" and "absence of a suitable adviser (5.9%)". Non execution of the controls for stressful work factors was due to "lack of knowledge as to how to control (15.6%)" and "lack of time to perform (10.2%)". Consequently, as a result of the survey, it was suggested that it is necessary to enlighten the employers of SEEs as to the importance of occupational health controls. It is also necessary to propose low-cost, feasible control methods.

Mechanisms Mediating Vibration-induced Chronic Musculoskeletal Pain Analyzed in the Rat

PubMed Central

Dina, Olayinka A.; Joseph, Elizabeth K.; Levine, Jon D.; Green, Paul G.

2009-01-01

While occupational exposure to vibration is a common cause of acute and chronic musculoskeletal pain, eliminating exposure produces limited symptomatic improvement, and re-exposure precipitates rapid recurrence or exacerbation. To evaluate mechanisms underlying these pain syndromes, we have developed a model in the rat, in which exposure to vibration (60–80 Hz) induces, in skeletal muscle, both acute mechanical hyperalgesia as well as long-term changes characterized by enhanced hyperalgesia to a pro-inflammatory cytokine or re-exposure to vibration. Exposure of a hind limb to vibration produced mechanical hyperalgesia measured in the gastrocnemius muscle of the exposed hind limb, which persisted for ~2 weeks. When nociceptive thresholds had returned to baseline, exposure to a pro-inflammatory cytokine or re-exposure to vibration produced markedly prolonged hyperalgesia. The chronic prolongation of vibration- and cytokine-hyperalgesia induced by vibration was prevented by spinal intrathecal injection of oligodeoxynucleotide (ODN) antisense to protein kinase Cε, a second messenger in nociceptors implicated in the induction and maintenance of chronic pain. Vibration-induced hyperalgesia was inhibited by spinal intrathecal administration of ODN antisense to receptors for the type-1 tumor necrosis factor-α (TNFα) receptor. Finally, in TNFα-pretreated muscle, subsequent vibration-induced hyperalgesia was markedly prolonged. Perspective These studies establish a model of vibration-induced acute and chronic musculoskeletal pain, and identify the proinflammatory cytokine TNFα and the second messenger PKCε as targets against which therapies might be directed to prevent and/or treat this common and very debilitating chronic pain syndrome. PMID:19962353

The effects of mirror therapy on arm and hand function in subacute stroke in patients.

PubMed

Radajewska, Alina; Opara, Józef A; Kucio, Cezary; Błaszczyszyn, Monika; Mehlich, Krzysztof; Szczygiel, Jarosław

2013-09-01

The aim of this study was to evaluate the effect of mirror therapy on arm and hand function in subacute stroke in patients. The study included 60 hemiparetic right-handed patients after ischemic stroke 8-10 weeks after onset. They underwent stationary comprehensive rehabilitation in the rehabilitation centre. They were divided into two randomly assigned groups: mirror (n=30) and control (n=30). For both groups, two subgroups were created: one that included patients with right arm paresis (n=15) and the other that included patients with left arm paresis (n=15). The mirror group received an additional intervention: training with a mirror for 5 days/week, 2 sessions/day, for 21 days. Each single session lasted for 15 min. The control group (n=30) underwent a conventional rehabilitation program without mirror therapy. To evaluate self-care in performing activities of daily living, the Functional Index 'Repty' was used. To evaluate hand and arm function, the Frenchay Arm Test and the Motor Status Score were used. Measurements were performed twice: before and after 21 days of applied rehabilitation. No significant improvement in hand and arm function in both subgroups in Frenchay Arm Test and Motor Status Score scales was observed. However, there was a significant improvement in self-care of activities of daily living in the right arm paresis subgroup in the mirror group measured using the Functional Index 'Repty'. Mirror therapy improves self-care of activities of daily living for patients with right arm paresis after stroke.

Determinants explaining the variability of hand-transmitted vibration emissions from two different work tasks: grinding and cutting using angle grinders.

PubMed

Liljelind, Ingrid; Pettersson, Hans; Nilsson, Leif; Wahlström, Jens; Toomingas, Allan; Lundström, Ronnie; Burström, Lage

2013-10-01

There are numerous factors including physical, biomechanical, and individual that influence exposure to hand-transmitted vibration (HTV) and cause variability in the exposure measurements. Knowledge of exposure variability and determinants of exposure could be used to improve working conditions. We performed a quasi-experimental study, where operators performed routine work tasks in order to obtain estimates of the variance components and to evaluate the effect of determinants, such as machine-wheel combinations and individual operator characteristics. Two pre-defined simulated work tasks were performed by 11 operators: removal of a weld puddle of mild steel and cutting of a square steel pipe. In both tasks, four angle grinders were used, two running on compressed air and two electrically driven. Two brands of both grinding and cutting wheels were used. Each operator performed both tasks twice in a random order with each grinder and wheel and the time to complete each task was recorded. Vibration emission values were collected and the wheel wear was measured as loss of weight. Operators' characteristics collected were as follows: age, body height and weight, length and volume of their hands, maximum hand grip force, and length of work experience with grinding machines (years). The tasks were also performed by one operator who used four machines of the same brand. Mixed and random effects models were used in the statistical evaluation. The statistical evaluation was performed for grinding and cutting separately and we used a measure referring to the sum of the 1-s r.m.s. average frequency-weighted acceleration over time for completing the work task (a(sa)). Within each work task, there was a significant effect as a result of the determinants 'the machine used', 'wheel wear', and 'time taken to complete the task'. For cutting, 'the brand of wheel' used also had a significant effect. More than 90% of the inherent variability in the data was explained by the determinants. The two electrically powered machines had a mean a(sa) that was 2.6 times higher than the two air-driven machines. For cutting, the effect of the brand of wheel on a(sa) was ~0.1 times. The a(sa) increased both with increasing wheel wear and with time taken to complete the work task. However, there were also a number of interaction effects which, to a minor extent, modified the a(sa). Only a minor part (1%) of the total variability was attributed to the operator: for cutting, the volume of the hands, maximum grip force, and body weight were significant, while for grinding, it was the maximum grip force. There was no clear difference in a(sa) between the four copies of the same brand of each machine. By including determinants that were attributed to the brand of both machine and wheel used as well as the time taken to complete the work task, we were able to explain >90% of the variability. The dominating determinant was the brand of the machine. Little variability was found between operators, indicating that the overall effect as due to the operator was small.

Exposure-response relationships for annoyance due to freight and passenger railway vibration exposure in residential environments.

PubMed

Sharp, Calum; Woodcock, James; Sica, Gennaro; Peris, Eulalia; Moorhouse, Andrew T; Waddington, David C

2014-01-01

In this work, exposure-response relationships for annoyance due to freight and passenger railway vibration exposure in residential environments are developed, so as to better understand the differences in human response to these two sources of environmental vibration. Data for this research come from a field study comprising interviews with respondents and measurements of their vibration exposure (N = 752). A logistic regression model is able to accurately classify 96% of these measured railway vibration signals as freight or passenger based on two signal properties that quantify the duration and low frequency content of each signal. Exposure-response relationships are then determined using ordinal probit modeling with fixed thresholds. The results indicate that people are able to distinguish between freight and passenger railway vibration, and that the annoyance response due to freight railway vibration is significantly higher than that due to passenger railway vibration, even for equal levels of exposure. In terms of a community tolerance level, the population studied is 15 dB (re 10(-6) m s(-2)) more tolerant to passenger railway vibration than freight railway vibration. These results have implications for the expansion of freight traffic on rail, or for policies to promote passenger railway.

Effect of shelf aging on vibration transmissibility of anti-vibration gloves

PubMed Central

SHIBATA, Nobuyuki

2017-01-01

Anti-vibration gloves have been used in real workplaces to reduce vibration transmitted through hand-held power tools to the hand. Generally materials used for vibration attenuation in gloves are resilient materials composed of certain synthetic and/or composite polymers. The mechanical characteristics of the resilient materials used in anti-vibration gloves are prone to be influenced by environmental conditions such as temperature, humidity, and photo-irradiation, which cause material degradation and aging. This study focused on the influence of shelf aging on the vibration attenuation performance of air-packaged anti-vibration gloves following 2 yr of shelf aging. Effects of shelf aging on the vibration attenuation performance of anti-vibration gloves were examined according to the Japan industrial standard JIS T8114 test protocol. The findings indicate that shelf aging induces the reduction of vibration attenuation performance in air-packaged anti-vibration gloves. PMID:28978817

Does intraoperative navigation improve the accuracy of pedicle screw placement in the apical region of dystrophic scoliosis secondary to neurofibromatosis type I: comparison between O-arm navigation and free-hand technique.

PubMed

Jin, Mengran; Liu, Zhen; Liu, Xingyong; Yan, Huang; Han, Xiao; Qiu, Yong; Zhu, Zezhang

2016-06-01

To assess the accuracy of O-arm-navigation-based pedicle screw insertion in dystrophic scoliosis secondary to NF-1 and compare it with free-hand pedicle screw insertion technique. 32 patients with dystrophic NF-1-associated scoliosis were divided into two groups. A total of 92 pedicle screws were implanted in apical region (two vertebrae above and below the apex each) in 13 patients using O-arm-based navigation (O-arm group), and 121 screws were implanted in 19 patients using free-hand technique (free-hand group). The postoperative CT images were reviewed and analyzed for pedicle violation. The screw penetration was divided into four grades: grade 0 (ideal placement), grade 1 (penetration <2 mm), grade 2 (penetration between 2 and 4 mm), and grade 3 (penetration >4 mm). The accuracy rate of pedicle screw placement (grade 0, 1) was significantly higher in the O-arm group (79 %, 73/92) compared to 67 % (81/121) of the free-hand group (P = 0.045). Meanwhile, a significantly lower prevalence of grade 2-3 perforation was observed in the O-arm group (21 vs. 33 %, P < 0.05), and the incidence of medial perforation was significantly minimized by using O-arm navigation compared to free-hand technique (2 vs. 15 %, P < 0.01). Moreover, the implant density in apical region was significantly elevated by using O-arm navigation (58 vs. 42 %, P < 0.001). We reported 79 % accuracy of O-arm-based pedicle screw placement in dystrophic NF-1-associated scoliosis. O-arm navigation system does facilitate pedicle screw insertion in dystrophic NF-1-associated scoliosis, demonstrating superiorities in the safety and accuracy of pedicle screw placement in comparison with free-hand technique.

Hazardous materials emergency response mobile robot

NASA Technical Reports Server (NTRS)

Stone, Henry W. (Inventor); Lloyd, James (Inventor); Alahuzos, George (Inventor)

1992-01-01

A simple or unsophisticated robot incapable of effecting straight-line motion at the end of its arm inserts a key held in its end effector or hand into a door lock with nearly straight-line motion by gently thrusting its back heels downwardly so that it pivots forwardly on its front toes while holding its arm stationary. The relatively slight arc traveled by the robot's hand is compensated by a complaint tool with which the robot hand grips the door key. A visible beam is projected through the axis of the hand or gripper on the robot arm end at an angle to the general direction in which the robot thrusts the gripper forward. As the robot hand approaches a target surface, a video camera on the robot wrist watches the beam spot on the target surface fall from a height proportional to the distance between the robot hand and the target surface until the beam spot is nearly aligned with the top of the robot hand. Holes in the front face of the hand are connected through internal passages inside the arm to an on-board chemical sensor. Full rotation of the hand or gripper about the robot arm's wrist is made possible by slip rings in the wrist which permit passage of the gases taken in through the nose holes in the front of the hand through the wrist regardless of the rotational orientation of the wrist.

Human response to vibration in residential environments.

PubMed

Waddington, David C; Woodcock, James; Peris, Eulalia; Condie, Jenna; Sica, Gennaro; Moorhouse, Andrew T; Steele, Andy

2014-01-01

This paper presents the main findings of a field survey conducted in the United Kingdom into the human response to vibration in residential environments. The main aim of this study was to derive exposure-response relationships for annoyance due to vibration from environmental sources. The sources of vibration considered in this paper are railway and construction activity. Annoyance data were collected using questionnaires conducted face-to-face with residents in their own homes. Questionnaires were completed with residents exposed to railway induced vibration (N = 931) and vibration from the construction of a light rail system (N = 350). Measurements of vibration were conducted at internal and external positions from which estimates of 24-h vibration exposure were derived for 1073 of the case studies. Sixty different vibration exposure descriptors along with 6 different frequency weightings were assessed as potential predictors of annoyance. Of the exposure descriptors considered, none were found to be a better predictor of annoyance than any other. However, use of relevant frequency weightings was found to improve correlation between vibration exposure and annoyance. A unified exposure-response relationship could not be derived due to differences in response to the two sources so separate relationships are presented for each source.

Effect of two contrasting interventions on upper limb chronic pain and disability: a randomized controlled trial.

PubMed

Sundstrup, Emil; Jakobsen, Markus D; Andersen, Christoffer H; Jay, Kenneth; Persson, Roger; Aagaard, Per; Andersen, Lars L

2014-01-01

Chronic pain and disability of the arm, shoulder, and hand severely affect labor market participation. Ergonomic training and education is the default strategy to reduce physical exposure and thereby prevent aggravation of pain. An alternative strategy could be to increase physical capacity of the worker by physical conditioning. To investigate the effect of 2 contrasting interventions, conventional ergonomic training (usual care) versus resistance training, on pain and disability in individuals with upper limb chronic pain exposed to highly repetitive and forceful manual work. Examiner-blinded, parallel-group randomized controlled trial with allocation concealment. Slaughterhouses located in Denmark, Europe. Sixty-six adults with chronic pain in the shoulder, elbow/forearm, or hand/wrist and work disability were randomly allocated to 10 weeks of specific resistance training for the shoulder, arm, and hand muscles for 3 x 10 minutes per week, or ergonomic training and education (usual care control group). Pain intensity (average of shoulder, arm, and hand, scale 0 - 10) was the primary outcome, and disability (Work module of DASH questionnaire) as well as isometric shoulder and wrist muscle strength were secondary outcomes. Pain intensity, disability, and muscle strength improved more following resistance training than usual care (P < 0.001, P = 0.05, P <0.0001, respectively [corrected]). Pain intensity decreased by 1.5 points (95% confidence interval -2.0 to -0.9) following resistance training compared with usual care, corresponding to an effect size of 0.91 (Cohen's d). Blinding of participants is not possible in behavioral interventions. However, at baseline outcome expectations of the 2 interventions were similar. Resistance training at the workplace results in clinical relevant improvements in pain, disability, and muscle strength in adults with upper limb chronic pain exposed to highly repetitive and forceful manual work. NCT01671267.

The relationship between occupational noise and vibration exposure and headache/eyestrain, based on the fourth Korean Working Condition Survey (KWCS).

PubMed

Kim, Jihyun; Lee, Wanhyung; Won, Jong-Uk; Yoon, Jin-Ha; Seok, Hongdeok; Kim, Yeong-Kwang; Lee, Seunghyun; Roh, Jaehoon

2017-01-01

The individual and combined effect of occupational noise and vibration exposures, on workers' health has not been thoroughly investigated. In order to find better ways to prevent and manage workers' headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain. We used data from the fourth Korean Working Condition Survey (2014). After applying inclusion and exclusion criteria, 25,751 workers were included. Occupational noise and vibration exposure and the prevalence of headache/eyestrain were investigated by self-reported survey. Chi-square tests were used to compare differences in baseline characteristics between the group with headache/eyestrain and the group without. Odds ratios and 95% confidence intervals were estimated using a logistic regression model adjusted for several covariates. Area under the receiver operating characteristics curve (AUROC) analysis was used to evaluate the effect of occupational noise and/or vibration exposure. Among the 25,751 study subjects, 4,903 had experienced headache/eyestrain in the preceding year. There were significant differences in age, education level, household income, occupational classification, shift work, occupational vibration exposure, and occupational noise exposure between the two groups (all p<0.05). The odds ratios between each exposure and headache/eyestrain increased proportionally with the level of exposure, increasing from 1.08 to 1.26 with increasing vibration exposure, and from 1.25 to 1.41 with increasing noise exposure. According to the AUROC analysis, the predictive power of each exposure was significant, and increased when the two exposures were considered in combination. The findings of this study show that both occupational noise and vibration exposures are associated with headache/eyestrain; noise exposure more strongly so. However, when the two exposures are considered in combination, the explanatory power for headache/eyestrain is increased. Therefore, efforts aimed at reducing and managing occupational noise and vibration exposure are crucial to maintaining workers' health.

The relationship between occupational noise and vibration exposure and headache/eyestrain, based on the fourth Korean Working Condition Survey (KWCS)

PubMed Central

Kim, Jihyun; Lee, Wanhyung; Won, Jong-Uk; Yoon, Jin-Ha; Seok, Hongdeok; Kim, Yeong-Kwang; Lee, Seunghyun

2017-01-01

Introduction The individual and combined effect of occupational noise and vibration exposures, on workers’ health has not been thoroughly investigated. In order to find better ways to prevent and manage workers’ headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain. Methods We used data from the fourth Korean Working Condition Survey (2014). After applying inclusion and exclusion criteria, 25,751 workers were included. Occupational noise and vibration exposure and the prevalence of headache/eyestrain were investigated by self-reported survey. Chi-square tests were used to compare differences in baseline characteristics between the group with headache/eyestrain and the group without. Odds ratios and 95% confidence intervals were estimated using a logistic regression model adjusted for several covariates. Area under the receiver operating characteristics curve (AUROC) analysis was used to evaluate the effect of occupational noise and/or vibration exposure. Results Among the 25,751 study subjects, 4,903 had experienced headache/eyestrain in the preceding year. There were significant differences in age, education level, household income, occupational classification, shift work, occupational vibration exposure, and occupational noise exposure between the two groups (all p<0.05). The odds ratios between each exposure and headache/eyestrain increased proportionally with the level of exposure, increasing from 1.08 to 1.26 with increasing vibration exposure, and from 1.25 to 1.41 with increasing noise exposure. According to the AUROC analysis, the predictive power of each exposure was significant, and increased when the two exposures were considered in combination. Discussion The findings of this study show that both occupational noise and vibration exposures are associated with headache/eyestrain; noise exposure more strongly so. However, when the two exposures are considered in combination, the explanatory power for headache/eyestrain is increased. Therefore, efforts aimed at reducing and managing occupational noise and vibration exposure are crucial to maintaining workers’ health. PMID:28542287

Combined Effects of High-Speed Railway Noise and Ground Vibrations on Annoyance.

PubMed

Yokoshima, Shigenori; Morihara, Takashi; Sato, Tetsumi; Yano, Takashi

2017-07-27

The Shinkansen super-express railway system in Japan has greatly increased its capacity and has expanded nationwide. However, many inhabitants in areas along the railways have been disturbed by noise and ground vibration from the trains. Additionally, the Shinkansen railway emits a higher level of ground vibration than conventional railways at the same noise level. These findings imply that building vibrations affect living environments as significantly as the associated noise. Therefore, it is imperative to quantify the effects of noise and vibration exposures on each annoyance under simultaneous exposure. We performed a secondary analysis using individual datasets of exposure and community response associated with Shinkansen railway noise and vibration. The data consisted of six socio-acoustic surveys, which were conducted separately over the last 20 years in Japan. Applying a logistic regression analysis to the datasets, we confirmed the combined effects of vibration/noise exposure on noise/vibration annoyance. Moreover, we proposed a representative relationship between noise and vibration exposures, and the prevalence of each annoyance associated with the Shinkansen railway.

Transmission of vibration through gloves: effects of contact area.

PubMed

Md Rezali, Khairil Anas; Griffin, Michael J

2017-01-01

For three samples of material (12.5, 25.0 and 37.5 mm diameter) from each of three gloves, the dynamic stiffnesses and the vibration transmissibilities of the materials (to both the palm of the hand and the thenar eminence) were measured at frequencies from 10 to 300 Hz. Additional measurements showed the apparent masses of the hand at the palm and the thenar eminence were independent of contact area at frequencies less than about 40 Hz, but increased with increasing area at higher frequencies. The stiffness and damping of the glove materials increased with increasing area. These changes caused material transmissibilities to the hand to increase with increasing area. It is concluded that the size of the area of contact has a large influence on the transmission of vibration through a glove to the hand. The area of contact should be well-defined and controlled when evaluating the transmission of vibration through gloves. Practitioner Summary: The transmission of vibration through gloves depends on both the dynamic stiffness of glove material and the dynamic response of the hand. Both of these depend on the size of the contact area between a glove material and the hand, which should be taken into account when assessing glove transmissibility.

Apparatus for providing vibrotactile sensory substitution of force feedback

NASA Technical Reports Server (NTRS)

Massimino, Michael J. (Inventor); Sheridan, Thomas B. (Inventor); Patrick, Nicholas J. M. (Inventor)

1997-01-01

A feedback apparatus for an operator to control an effector that is remote from the operator to interact with a remote environment has a local input device to be manipulated by the operator. Sensors in the effector's environment are capable of sensing the amplitude of forces arising between the effector and its environment, the direction of application of such forces, or both amplitude and direction. A feedback signal corresponding to such a component of the force, is generated and transmitted to the environment of the operator. The signal is transduced into a vibrotactile sensory substitution signal to which the operator is sensitive. Vibration producing apparatus present the vibrotactile signal to the operator. The full range of the force amplitude may be represented by a single, mechanical vibrator. Vibrotactile display elements can be located on the operator's limbs, such as on the hand, fingers, arms, legs, feet, etc. The location of the application of the force may also be specified by the location of a vibrotactile display on the operator's body. Alternatively, the location may be specified by the frequency of a vibrotactile signal.

Consequences of impact on arm (elbow and shoulder joints) caused by ball hitting, theoretical analysis

NASA Astrophysics Data System (ADS)

Negrea, Adina; Busuioceanu, Ioana Iuliana

2018-02-01

Present paper estimates the mechanics of the impact of a ball and a hand-arm, during the sports training using a classical model for the hand-arm system, avoiding the contribution of the coefficient of restitution. The results of this investigation are focused on the equations needed to find out theimpact reactions in elbow and shoulder joints, for different anthropometric data. Also, the computing of the position of mass centers and the moments of inertia for each constitutive part of hand-arm system is made.

Spatial patterns of cutaneous vibration during whole-hand haptic interactions

PubMed Central

Hayward, Vincent; Visell, Yon

2016-01-01

We investigated the propagation patterns of cutaneous vibration in the hand during interactions with touched objects. Prior research has highlighted the importance of vibrotactile signals during haptic interactions, but little is known of how vibrations propagate throughout the hand. Furthermore, the extent to which the patterns of vibrations reflect the nature of the objects that are touched, and how they are touched, is unknown. Using an apparatus comprised of an array of accelerometers, we mapped and analyzed spatial distributions of vibrations propagating in the skin of the dorsal region of the hand during active touch, grasping, and manipulation tasks. We found these spatial patterns of vibration to vary systematically with touch interactions and determined that it is possible to use these data to decode the modes of interaction with touched objects. The observed vibration patterns evolved rapidly in time, peaking in intensity within a few milliseconds, fading within 20–30 ms, and yielding interaction-dependent distributions of energy in frequency bands that span the range of vibrotactile sensitivity. These results are consistent with findings in perception research that indicate that vibrotactile information distributed throughout the hand can transmit information regarding explored and manipulated objects. The results may further clarify the role of distributed sensory resources in the perceptual recovery of object attributes during active touch, may guide the development of approaches to robotic sensing, and could have implications for the rehabilitation of the upper extremity. PMID:27035957

Lasting improvements in left spatial neglect following a protocol combining neck-muscle vibration and voluntary arm movements: a case-study.

PubMed

Ceyte, Hadrien; Beis, Jean-Marie; Simon, Mathilde; Rémy, Ariane; Anxionnat, René; Paysant, Jean; Caudron, Sébastien

2018-01-22

Beyond promising experimental results of sensory passive stimulations in spatial cognition disorders, some questions still remain regarding interests of these stimulations during the daily activities in neglect. The aim of this case-study was to evaluate the effects of a protocol combining left neck-muscle vibration with daily simple movements, like arm pointing movements, on perceptivo-locomotor deficits in a left spatial neglect patient. Two neuropsychological tests, one subjective straight-ahead pointing (SSA) test and one wheelchair navigation test were carried out before the combination protocol, immediately after, 1 h later, and 24 h later. The results showed a reduction of neglect spatial bias following the protocol lasted at least 24 h in all the tests (except for the SSA test due to the unavailability of the pointing device). The range of improvements in the symptoms of spatial neglect suggests that this therapeutic intervention based on the combining neck-muscle vibration to voluntary arm movements could be a useful treatment for this condition. One of future investigation axes should be the development of a vibratory tool in order to facilitate the combining this proprioceptive stimulation to daily activities. Implications for rehabilitation Spatial neglect is a perplexing neuropsychological syndrome, affecting different domains of spatial cognition and impacting also the functional domain. The treatments based on neck-muscle vibration are simple to use, non-invasive and requires none active participation of patient. A therapeutic intervention based on the combining left neck-muscle vibration and voluntary arm movements in a left-spatial-neglect show a lasting reduction of symptoms especially in daily activities. The combination of treatments based on the Bottom-Up approach opens innovative perspectives in rehabilitation.

Reach-to-grasp movement as a minimization process.

PubMed

Yang, Fang; Feldman, Anatol G

2010-02-01

It is known that hand transport and grasping are functionally different but spatially coordinated components of reach-to-grasp (RTG) movements. As an extension of this notion, we suggested that body segments involved in RTG movements are controlled as a coherent ensemble by a global minimization process associated with the necessity for the hand to reach the motor goal. Different RTG components emerge following this process without pre-programming. Specifically, the minimization process may result from the tendency of neuromuscular elements to diminish the spatial gap between the actual arm-hand configuration and its virtual (referent) configuration specified by the brain. The referent configuration is specified depending on the object shape, localization, and orientation. Since the minimization process is gradual, it can be interrupted and resumed following mechanical perturbations, at any phase during RTG movements, including hand closure. To test this prediction of the minimization hypothesis, we asked subjects to reach and grasp a cube placed within the reach of the arm. Vision was prevented during movement until the hand returned to its initial position. As predicted, by arresting wrist motion at different points of hand transport in randomly selected trials, it was possible to halt changes in hand aperture at any phase, not only during hand opening but also during hand closure. Aperture changes resumed soon after the wrist was released. Another test of the minimization hypothesis was made in RTG movements to an object placed beyond the reach of the arm. It has previously been shown (Rossi et al. in J Physiol 538:659-671, 2002) that in such movements, the trunk motion begins to contribute to hand transport only after a critical phase when the shifts in the referent arm configuration have finished (at about the time when hand velocity is maximal). The minimization rule suggests that when the virtual contribution of the arm to hand transport is completed, guidance of hand aperture switches from the arm to the trunk control system. As a consequence, hand aperture changes can be halted by trunk arrests but only if they are prolonged beyond a critical phase. As predicted, hand transport and hand aperture in RTG movements beyond the reach of the arm were halted by trunk arrests only if they were prolonged beyond the time of peak hand velocity. Hand motion and aperture changes resumed only when the trunk was released. While supporting the minimization hypothesis, our findings imply that not only spatial but also temporal characteristics of each component, including the shortest, hand closure component of RTG movements, are controlled in a flexible, task-specific way.

Timing variability of reach trajectories in left versus right hemisphere stroke.

PubMed

Freitas, Sandra Maria Sbeghen Ferreira; Gera, Geetanjali; Scholz, John Peter

2011-10-24

This study investigated trajectory timing variability in right and left stroke survivors and healthy controls when reaching to a centrally located target under a fixed target condition or when the target could suddenly change position after reach onset. Trajectory timing variability was investigated with a novel method based on dynamic programming that identifies the steps required to time warp one trial's acceleration time series to match that of a reference trial. Greater trajectory timing variability of both hand and joint motions was found for the paretic arm of stroke survivors compared to their non-paretic arm or either arm of controls. Overall, the non-paretic left arm of the LCVA group and the left arm of controls had higher timing variability than the non-paretic right arm of the RCVA group and right arm of controls. The shoulder and elbow joint warping costs were consistent predictors of the hand's warping cost for both left and right arms only in the LCVA group, whereas the relationship between joint and hand warping costs was relatively weak in control subjects and less consistent across arms in the RCVA group. These results suggest that the left hemisphere may be more involved in trajectory timing, although the results may be confounded by skill differences between the arms in these right hand dominant participants. On the other hand, arm differences did not appear to be related to differences in targeting error. The paretic left arm of the RCVA exhibited greater trajectory timing variability than the paretic right arm of the LCVA group. This difference was highly correlated with the level of impairment of the arms. Generally, the effect of target uncertainty resulted in slightly greater trajectory timing variability for all participants. The results are discussed in light of previous studies of hemispheric differences in the control of reaching, in particular, left hemisphere specialization for temporal control of reaching movements. Copyright © 2011 Elsevier B.V. All rights reserved.

Curiosity First Scoop of Mars, in Vibration Movie

NASA Image and Video Library

2012-10-08

This image from a video shows the first Martian material collected by the scoop on the robotic arm of NASA Mars rover Curiosity. The material vibrated inside the scoop after it was lifted from the ground.

Hazardous materials emergency response mobile robot

NASA Technical Reports Server (NTRS)

Stone, Henry W. (Inventor); Lloyd, James W. (Inventor); Alahuzos, George A. (Inventor)

1995-01-01

A simple or unsophisticated robot incapable of effecting straight-line motion at the end of its arm is presented. This robot inserts a key held in its end effector or hand into a door lock with nearly straight-line motion by gently thrusting its back heels downwardly so that it pivots forwardly on its front toes while holding its arm stationary. The relatively slight arc traveled by the robot's hand is compensated by a complaint tool with which the robot hand grips the door key. A visible beam is projected through the axis of the hand or gripper on the robot arm end at an angle to the general direction in which the robot thrusts the gripper forward. As the robot hand approaches a target surface, a video camera on the robot wrist watches the beam spot on the target surface fall from a height proportional to the distance between the robot hand and the target surface until the beam spot is nearly aligned with the top of the robot hand. Holes in the front face of the hand are connected through internal passages inside the arm to an on-board chemical sensor. Full rotation of the hand or gripper about the robot arm's wrist is made possible by slip rings in the wrist which permit passage of the gases taken in through the nose holes in the front of the hand through the wrist regardless of the rotational orientation of the wrist.

[Hand fine motor skills and use of both hand and arm in subjects after a stroke: a systematic review].

PubMed

Ostolaza, M; Abudarham, J; Dilascio, S; Drault-Boedo, E; Gallo, S; Garcete, A; Kramer, M; Maiaru, M; Mendelevich, A; Modica, M; Peralta, F; Sanchez-Correa, C

2017-04-01

In clinical practice it is important to be able to assess the function of the upper limb of the patient who has suffered a stroke. There is currently no systemic review that could identify assessment tools for the 'fine use of the hand' and 'use of both hand and arm'. Primary, to identify observational tools which can assess the fine use of the hand and the use of both hand and arm in patients with stroke sequels. Secondary, to analyze the bias risk in the included articles, describing and categorizing the clinical utility, validity and reliability. A search was carried in Medline, LILACS, SciELO and Open Grey, which included articles published until October 2015. Studies that validate assessing tools of the upper limb in subjects with a stroke sequel which evaluate the fine use of the hand and the use of both hand and arm were included. Eleven tools in evaluate observational haven been selected, which assess the fine use of the hand and the use of hand and arm. In every case both validity and reliability have been reported, but clinical utility has been less considered for assessment. The studies that researched these tools showed a high risk of bias in their development. ARAT-19 showed a lower bias risk, but when it has to do with applicability and the reference trial is taken into account, the level of concern is high.

Differential effect of muscle vibration on intracortical inhibitory circuits in humans

PubMed Central

Rosenkranz, Karin; Rothwell, John C

2003-01-01

Low amplitude muscle vibration (0.5 ms; 80 Hz; duration 1.5 s) was applied in turn to each of three different intrinsic hand muscles (first dorsal interosseus, FDI; abductor pollicis brevis, APB; and abductor digiti minimi, ADM) in order to test its effect on the EMG responses evoked by transcranial magnetic stimulation (TMS). Recordings were also taken from flexor and extensor carpi radialis (FCR and ECR, respectively). We evaluated the amplitude of motor evoked potentials (MEPs) produced by a single TMS pulse, short interval intracortical inhibition and facilitation (SICI and ICF) and long interval intracortical inhibition (LICI). TMS pulses were applied 1 s after the start of vibration with subjects relaxed throughout. Vibration increased the amplitude of MEPs evoked in the vibrated muscle (162 ± 6 % of MEP with no vibration; mean ± s.e.m.), but suppressed MEPs in the two non-vibrated hand muscles (72 ± 9 %). Compared with no vibration (test response reduced to 51 ± 5 % of control), there was less SICI in the vibrated muscle (test response reduced to 92 ± 28 % of control) and more in the non-vibrated hand muscles (test response reduced to 27 ± 5 % of control). The opposite occurred for LICI: compared with the no vibration condition (test response reduced to 33 ± 6 % control), there was more LICI in the vibrated muscle (test response reduced to 17 ± 3 % control) than in the non-vibrated hand muscles (test response reduced to 80 ± 11 % control) even when the intensity of the test stimulus was adjusted to compensate for the changes in baseline MEP. There was no effect on ICF. Cutaneous stimulation of the index finger (80 Hz, 1.5 s duration, twice sensory threshold) had no consistent differential effect on any of the parameters. We conclude that vibratory input from muscle can differentially modulate excitability in motor cortical circuits. PMID:12821723

Evaluation of reaction time performance and subjective drowsiness during whole-body vibration exposure

NASA Astrophysics Data System (ADS)

Azizan, A.; Zali, Z.; Padil, H.

2018-05-01

Despite the automotive industry’s interest in how vibration affects the level of human comfort, there is little focus on the effect of vibration on drowsiness level. Thus, this study involves eighteen healthy male participants to study the effect of exposure to vibration on the drowsiness level. Prior to the experiment, the total transmitted vibration measured at interfaces between the seat pan and seat back to the human body for each participant was modified to become 0.2 ms-2 r.m.s and 0.4 ms-2 r.m.s. During the experiment, the participants were seated and exposed to 20-minutes of Gaussian random vibration with frequency band 1-15 Hz at two level of amplitude (low vibration amplitude and medium vibration amplitude) on separate days. The level of drowsiness was measured using a PVT test prior and after exposure to the vibration while participants rated their subjective drowsiness by using the Karolinska Sleepiness Scale (KSS). The significant increase in the number of lapse and reaction time because of the exposure to vibration in both conditions provide strong evidence of drowsiness. In this regard, the medium vibration amplitude shows a more prominent effect. All participants have shown a steady increase of drowsiness level in KSS. Meanwhile, there are no significant differences found between low vibration amplitude and medium vibration amplitude in the KSS. These findings suggest that human alertness level is greatly affected by the exposure to vibration and these effects are more pronounced at higher vibration amplitude. Both findings indicate that the presence of vibration promotes drowsiness, especially at higher vibration amplitude.

Combined Effects of High-Speed Railway Noise and Ground Vibrations on Annoyance

PubMed Central

Yokoshima, Shigenori; Morihara, Takashi; Sato, Tetsumi; Yano, Takashi

2017-01-01

The Shinkansen super-express railway system in Japan has greatly increased its capacity and has expanded nationwide. However, many inhabitants in areas along the railways have been disturbed by noise and ground vibration from the trains. Additionally, the Shinkansen railway emits a higher level of ground vibration than conventional railways at the same noise level. These findings imply that building vibrations affect living environments as significantly as the associated noise. Therefore, it is imperative to quantify the effects of noise and vibration exposures on each annoyance under simultaneous exposure. We performed a secondary analysis using individual datasets of exposure and community response associated with Shinkansen railway noise and vibration. The data consisted of six socio-acoustic surveys, which were conducted separately over the last 20 years in Japan. Applying a logistic regression analysis to the datasets, we confirmed the combined effects of vibration/noise exposure on noise/vibration annoyance. Moreover, we proposed a representative relationship between noise and vibration exposures, and the prevalence of each annoyance associated with the Shinkansen railway. PMID:28749452

Sister chromatid exchange analysis in workers exposed to noise and vibration.

PubMed

Silva, M J; Carothers, A; Castelo Branco, N A; Dias, A; Boavida, M G

1999-03-01

There has been a growing interest in the combined effects of noise and vibration. In a population of aeronautical workers diagnosed with vibroacoustic disease (VAD), a large incidence of malignancy was detected. These workers were exposed to large pressure amplitude (LPA) (> or = 90 dB SPL) noise, with energy content concentrated within the low frequency (LF) bands (< or = 500 Hz) and whole-body vibration (WBV). To our knowledge, there are no studies conducted in humans or animals that address the issue of the potential genotoxic effects of vibration combined with noise. In the present study, the levels of sister chromatid exchanges (SCE) and of cells with high frequencies of SCE (HFC) were analyzed in peripheral blood lymphocytes of workers employed in various occupations within the aeronautical industry. SCE and HFC were analyzed in lymphocytes of 50 workers occupationally exposed to noise and vibration and of 34 office-worker controls (G0). The exposed group included: 10 hand-vibrating tool operators (G1), 15 engine test cell technicians (G2), 12 aircraft run-up technicians (G3) and 13 Portuguese Air Force helicopter pilots (G4). Groups 2-4 were exposed to WBV and LPALF noise; group 1 was exposed to LPA high frequency noise and local vibration. Statistical analysis of the mean SCE count per cell was carried out by multiple regression analysis comparing various predictor variables: type of exposure, duration of exposure, age, and cigarette consumption. Only cigarette consumption and type of exposure were found to be significantly correlated with the mean SCE frequency. After allowing for the effects of smoking, the analysis indicates that: 1) there was no significant difference between G1 and G0 (p > 0.05); 2) the differences between G2 and G0, G3 and G0, G4 and G0 were all highly significant (p < 0.001); 3) there was no significant difference between G2 and G3 (p > 0.05), nor between G2 and G3 combined and G4 (p > 0.05); and 4) G2 and G4 combined had a significantly elevated mean SCE frequency compared G0 (p < 0.001). Statistical analysis of the proportion of HFC was consistent with these results. Our data suggest that occupational exposure to LPALF noise and WBV may lead to increased levels of SCE in men. These results also suggest a reason for the high incidence of malignancy in VAD patients. The observed effects may not reflect a direct action of these physical agents on DNA. Alternative explanations may lie in the noise-, vibration-, and/or stress-induced pathophysiological changes.

Innovative approaches to the rehabilitation of upper extremity hemiparesis using virtual environments

PubMed Central

MERIANS, A. S.; TUNIK, E.; FLUET, G. G.; QIU, Q.; ADAMOVICH, S. V.

2017-01-01

Aim Upper-extremity interventions for hemiparesis are a challenging aspect of stroke rehabilitation. Purpose of this paper is to report the feasibility of using virtual environments (VEs) in combination with robotics to assist recovery of hand-arm function and to present preliminary data demonstrating the potential of using sensory manipulations in VE to drive activation in targeted neural regions. Methods We trained 8 subjects for 8 three hour sessions using a library of complex VE’s integrated with robots, comparing training arm and hand separately to training arm and hand together. Instrumented gloves and hand exoskeleton were used for hand tracking and haptic effects. Haptic Master robotic arm was used for arm tracking and generating three-dimensional haptic VEs. To investigate the use of manipulations in VE to drive neural activations, we created a “virtual mirror” that subjects used while performing a unimanual task. Cortical activation was measured with functional MRI (fMRI) and transcranial magnetic stimulation. Results Both groups showed improvement in kinematics and measures of real-world function. The group trained using their arm and hand together showed greater improvement. In a stroke subject, fMRI data suggested virtual mirror feedback could activate the sensorimotor cortex contralateral to the reflected hand (ipsilateral to the moving hand) thus recruiting the lesioned hemisphere. Conclusion Gaming simulations interfaced with robotic devices provide a training medium that can modify movement patterns. In addition to showing that our VE therapies can optimize behavioral performance, we show preliminary evidence to support the potential of using specific sensory manipulations to selectively recruit targeted neural circuits. PMID:19158659

Physiological effects of railway vibration and noise on sleep

PubMed Central

Smith, Michael G.; Croy, Ilona; Ögren, Mikael; Hammar, Oscar; Lindberg, Eva; Persson Waye, Kerstin

2017-01-01

This paper evaluates the relative contribution of vibration and noise from railway on physiological sleep outcomes. Vibration from railway freight often accompanies airborne noise, yet is almost totally absent in the existing literature. In an experimental investigation, 23 participants, each sleeping for six nights in the laboratory, were exposed to 36 simulated railway freight pass-bys per night with vibration alone (aWd,max = 0.0204 ms−2), noise alone (LAF,max = 49.8 dB), or both vibration and noise simultaneously. A fourth exposure night involved 52 pass-bys with concurrent vibration and noise. Sleep was measured with polysomnography. Cardiac activity was measured with electrocardiography. The probability of cortical arousals or awakenings was greater following all exposures, including vibration alone, than spontaneous reaction probability (p < 0.05). The effects of vibration exposure and noise exposure on changes of sleep stage and arousals were directly additive. Vibration and noise exposure both induced heart rate acceleration above spontaneously expected fluctuations at baseline. The results indicate that vibration and noise are processed in the brain separately yet in parallel, with both contributing towards the likelihood of sleep disruption. The findings show that vibration is of importance when considering the impact of railway freight on sleep. PMID:28599531

Prevalence of vibration-induced white finger in fluorspar mines in Weardale.

PubMed Central

Chatterjee, D S; Petrie, A; Taylor, W

1978-01-01

A combined epidemiological and clinical study of vibration-induced white finger (VWF) was carried out involving 115 men in four fluorspar mines. The overall prevalence of VWF was found to be 50% among 42 vibration-exposed subjects, while that of constitutional white finger (CWF) was 5-6% in all men studied. The VWF latent interval was 1-19 years with a mean of 5-6 years. An association was observed between the exposure time and VWF stages which included 18 men in Stage 0, three in the intermediate Stage of 0T/0N, five in Stage 2 and 16 in Stage 3; no men were seen at Stage 1. Among those with VWF in Stage 3, the index, middle and ring fingers were affected in both hands and the little fingers and thumbs were last to be involved. Clinically, on general examination, apart from vibration-induced white finger, the men in the 'vibration' group were not as healthy as those in the 'control' group. The circumference of the index fingers was not significantly different for the different groups. Neurological tests showed that the ridge test and, to a lesser extent, the two-point discrimination and the light touch tests, could be regarded as useful for the diagnosis of VWF. PMID:698134

Hand washing with soap and water together with behavioural recommendations prevents infections in common work environment: an open cluster-randomized trial

PubMed Central

2012-01-01

Background Hand hygiene is considered as an important means of infection control. We explored whether guided hand hygiene together with transmission-limiting behaviour reduces infection episodes and lost days of work in a common work environment in an open cluster-randomized 3-arm intervention trial. Methods A total of 21 clusters (683 persons) were randomized to implement hand hygiene with soap and water (257 persons), with alcohol-based hand rub (202 persons), or to serve as a control (224 persons). Participants in both intervention arms also received standardized instructions on how to limit the transmission of infections. The intervention period (16 months) included the emergence of the 2009 influenza pandemic and the subsequent national hand hygiene campaign influencing also the control arm. Results In the total follow-up period there was a 6.7% reduction of infection episodes in the soap-and water arm (p = 0.04). Before the onset of the anti-pandemic campaign, a statistically significant (p = 0.002) difference in the mean occurrence of infection episodes was observed between the control (6.0 per year) and the soap-and-water arm (5.0 per year) but not between the control and the alcohol-rub arm (5.6 per year). Neither intervention had a decreasing effect on absence from work. Conclusions We conclude that intensified hand hygiene using water and soap together with behavioural recommendations can reduce the occurrence of self-reported acute illnesses in common work environment. Surprisingly, the occurrence of reported sick leaves also increased in the soap-and water-arm. Trial Registration ClinicalTrials.gov: NCT00981877 Source of funding The Finnish Work Environment Fund and the National Institute for Health and Welfare. PMID:22243622

Hand washing with soap and water together with behavioural recommendations prevents infections in common work environment: an open cluster-randomized trial.

PubMed

Savolainen-Kopra, Carita; Haapakoski, Jaason; Peltola, Piia A; Ziegler, Thedi; Korpela, Terttu; Anttila, Pirjo; Amiryousefi, Ali; Huovinen, Pentti; Huvinen, Markku; Noronen, Heikki; Riikkala, Pia; Roivainen, Merja; Ruutu, Petri; Teirilä, Juha; Vartiainen, Erkki; Hovi, Tapani

2012-01-16

Hand hygiene is considered as an important means of infection control. We explored whether guided hand hygiene together with transmission-limiting behaviour reduces infection episodes and lost days of work in a common work environment in an open cluster-randomized 3-arm intervention trial. A total of 21 clusters (683 persons) were randomized to implement hand hygiene with soap and water (257 persons), with alcohol-based hand rub (202 persons), or to serve as a control (224 persons). Participants in both intervention arms also received standardized instructions on how to limit the transmission of infections. The intervention period (16 months) included the emergence of the 2009 influenza pandemic and the subsequent national hand hygiene campaign influencing also the control arm. In the total follow-up period there was a 6.7% reduction of infection episodes in the soap-and water arm (p = 0.04). Before the onset of the anti-pandemic campaign, a statistically significant (p = 0.002) difference in the mean occurrence of infection episodes was observed between the control (6.0 per year) and the soap-and-water arm (5.0 per year) but not between the control and the alcohol-rub arm (5.6 per year). Neither intervention had a decreasing effect on absence from work. We conclude that intensified hand hygiene using water and soap together with behavioural recommendations can reduce the occurrence of self-reported acute illnesses in common work environment. Surprisingly, the occurrence of reported sick leaves also increased in the soap-and water-arm. ClinicalTrials.gov: NCT00981877 The Finnish Work Environment Fund and the National Institute for Health and Welfare.

Whole-body vibration exposure: a comprehensive field study.

PubMed

Ozkaya, N; Willems, B; Goldsheyder, D

1994-12-01

A comprehensive field study investigated whole-body vibration exposure levels experienced by the train operators of a large metropolitan subway system. The purposes of the study were to measure mechanical vibrations transmitted to the seated train operators, to calculate daily whole-body vibration exposure levels, and to compare these levels with maximum acceptable exposure levels recommended by the international standard on whole-body vibration (ISO 2631). The study also sought to identify factors that may influence mechanical vibrations transmitted to the operators and quantify their effects on the measured vibration levels. The study was carried out by dividing the subway system into subway lines, each line into southbound and northbound directions, and each direction into station-to-station observations. Triaxial measurements were made on all subway lines and for all car types used in the system. For each line, at least two round trips of data were collected. Time-weighted averages of the two sets of data were used for final presentation. A total of 48 round trips were made and more than 100 hours of vibration data was collected and analyzed. All phases of the study were carried out in accordance with the procedures outlined in ISO 2631. It was determined that 6 out of 20 subway lines had vibration levels higher than daily exposure limits recommended by ISO 2631. It was also determined that train speed was the most significant factor influencing vibration exposure levels.

Effect of acupuncture at right Hoku point on the bilateral vibration-induced finger flexion reflex in man.

PubMed

Takakura, N; Kanamaru, A; Sibuya, M; Homma, I

1992-01-01

Vibration applied to the volar side of the finger tip has been reported to induce finger flexion reflex. Acupuncture is reported to inhibit this vibration-induced finger flexion reflex (VFR) in the ipsilateral hand. The purpose of this study was to investigate the effect of unilateral acupuncture in the hand on VFR in both hands. As no systematic study on the relationship between VFR and the force of voluntary contraction with no vibration (Initial Force: IF) has been reported, this relationship was studied prior to the present study on acupuncture. VFR was induced by mechanical vibration on the volar side of the middle finger tip with 10 g to 500 g IF. With approximately 300 g IF, VFR was consistent. Therefore, approximately 300 g IF was applied for VFR induction to study the effect of acupuncture on VFR. A stainless steel needle was inserted into the right Hoku point and remained inserted (in-situ technique) for 10 minutes. VFR in both hands was significantly decreased by acupuncture at the right Hoku point (% control force of VFR: right, 67.8%; left, 74.6%). The present results suggest that acupuncture in the unilateral hand influences the bilateral reflex arc of VFR.

Mechanical and electromagnetic induction of protection against oxidative stress.

PubMed

Di Carlo, A L; White, N C; Litovitz, T A

2001-01-01

Cells and tissues can be protected against a potentially lethal stress by first exposing them to a brief dose of the same or different stress. This "pre-conditioning" phenomenon has been documented in many models of protection against oxidative stress, including ischemia/reperfusion and ultraviolet (UV) light exposure. Stimuli which induce this protective response include heat, chemicals, brief ischemia, and electromagnetic (EM) field exposures. We report here that constant mechanical vibration pre-conditions chick embryos, protecting them during subsequent stress from hypoxia or UV light exposure. Continuously mechanically vibrated embryos (60 Hz, 1 g (32 ft/s2), 20 min) exhibited nearly double the survival (67.5%, P < 0.001) after subsequent hypoxia as compared to non-vibrated controls (37.6%). As a second set of experiments, embryos were vibrated and then exposed to UV light stress. Those embryos that were vibrated prior to UV had nearly double the survival 3 h after UV exposure (66%, P < 0.001) as compared to controls (35%). The degree of protection, however, was dependent on the constancy of the vibration amplitude. When vibration was turned on and off at 1-s intervals throughout exposure, no increase in hypoxia protection was noted. For 50 s on/off vibration intervals, however, hypoxia protection comparable to continuous vibration was obtained. In contrast, random, inconstant mechanical vibration did not induce protection against subsequent UV exposure. These data suggest that to be an effective pre-conditioning agent, mechanical vibration must have a degree of temporally constancy (on/off intervals of greater than 1 s). Further experiments in both models (hypoxia and UV) indicated an interaction between vibration and EM field-induced protection. Vibration-induced hypoxia protection was inhibited by superposition of a random EM noise field (previously shown to inhibit EM field-induced protection). In addition, EM field-induced UV protection was inhibited by the superposition of random mechanical vibration. Thus, the superposition of either vibrational or EM noise during pre-conditioning virtually eliminated protection against hypoxia and UV. This link between EM field exposures and mechanical vibration is consistent with the hypothesis that cells sense these stimuli via a similar mechanism involving counter ion displacement.

Comparison of Annoyance from Railway Noise and Railway Vibration.

PubMed

Ögren, Mikael; Gidlöf-Gunnarsson, Anita; Smith, Michael; Gustavsson, Sara; Persson Waye, Kerstin

2017-07-19

The aim of this study is to compare vibration exposure to noise exposure from railway traffic in terms of equal annoyance, i.e., to determine when a certain noise level is equally annoying as a corresponding vibration velocity. Based on questionnaire data from the Train Vibration and Noise Effects (TVANE) research project from residential areas exposed to railway noise and vibration, the dose response relationship for annoyance was estimated. By comparing the relationships between exposure and annoyance for areas both with and without significant vibration exposure, the noise levels and vibration velocities that had an equal probability of causing annoyance was determined using logistic regression. The comparison gives a continuous mapping between vibration velocity in the ground and a corresponding noise level at the facade that are equally annoying. For equivalent noise level at the facade compared to maximum weighted vibration velocity in the ground the probability of annoyance is approximately 20% for 59 dB or 0.48 mm/s, and about 40% for 63 dB or 0.98 mm/s.

Exposure to whole-body vibration and seat transmissibility in a large sample of earth scrapers.

PubMed

Salmoni, Alan; Cann, Adam; Gillin, Kent

2010-01-01

It is often difficult to access a large sample of vehicles in various work environments to evaluate worker exposure to vibration such as in construction and mining. Thus the main purpose of the present research was to test vibration exposure in a relatively large number of earth scrapers. The second aim was to assess vibration exposure values on seat transmissibility. 33earth scrapers were assessed for both exposure to whole-body vibration and seat transmissibility. Two triaxial accelerometers, one placed on the seat and one on the floor directly below the seat, were used to gather whole-body vibration values (a(w)). Each machine was tested for a minimum of three complete work cycles: idling, scraping, travelling full, dumping, travelling empty back to the scrape site. Results showed that idling and scraping produced low levels of vibration when compared to travelling and dumping. Second, when the a(w) values were compared to the EU safety standards for an eight hour work day, the data (z axis) exceeded the exposure action value (0.5 m/s2) in all machines, and the exposure limit value (1.15 m/s2) in some. Implications; Operators of the scrapers were being exposed to unsafe levels of whole-body vibration. When the seats were assessed to see whether they were attenuating operator exposure to vibration, many of the seat effective amplitude transmissibility (SEAT) values exceeded 1.0. This meant that some of the seats were actually amplifying the vibration present at the floor, particularly in the y axis. Travelways should be kept smooth, operating speeds reduced, and new seats, effective in all three axes, designed.

Impact of body posture on laterality judgement and explicit recognition tasks performed on self and others' hands.

PubMed

Conson, Massimiliano; Errico, Domenico; Mazzarella, Elisabetta; De Bellis, Francesco; Grossi, Dario; Trojano, Luigi

2015-04-01

Judgments on laterality of hand stimuli are faster and more accurate when dealing with one's own than others' hand, i.e. the self-advantage. This advantage seems to be related to activation of a sensorimotor mechanism while implicitly processing one's own hands, but not during explicit one's own hand recognition. Here, we specifically tested the influence of proprioceptive information on the self-hand advantage by manipulating participants' body posture during self and others' hand processing. In Experiment 1, right-handed healthy participants judged laterality of either self or others' hands, whereas in Experiment 2, an explicit recognition of one's own hands was required. In both experiments, the participants performed the task while holding their left or right arm flexed with their hand in direct contact with their chest ("flexed self-touch posture") or with their hand placed on a wooden smooth surface in correspondence with their chest ("flexed proprioceptive-only posture"). In an "extended control posture", both arms were extended and in contact with thighs. In Experiment 1 (hand laterality judgment), we confirmed the self-advantage and demonstrated that it was enhanced when the subjects judged left-hand stimuli at 270° orientation while keeping their left arm in the flexed proprioceptive-only posture. In Experiment 2 (explicit self-hand recognition), instead, we found an advantage for others' hand ("self-disadvantage") independently from posture manipulation. Thus, position-related proprioceptive information from left non-dominant arm can enhance sensorimotor one's own body representation selectively favouring implicit self-hands processing.

Passive or simulated displacement of one arm (but not its mirror reflection) modulates the involuntary motor behavior of the other arm.

PubMed

Brun, C; Metral, M; Chancel, M; Kavounoudias, A; Luyat, M; Guerraz, M

2015-01-29

Recent studies of both healthy and patient populations have cast doubt on the mirror paradigm's beneficial effect on motor behavior. Indeed, the voluntary arm displacement that accompanies reflection in the mirror may be the determining factor in terms of the motor behavior of the contralateral arm. The objective of the present study was to assess the respective effects of mirror reflection and arm displacement (whether real or simulated) on involuntary motor behavior of the contralateral arm following sustained, isometric contraction (Kohnstamm phenomenon). Our results revealed that (i) passive displacement of one arm (displacement of the left arm via a motorized manipulandum moving at 4°/s) influenced the velocity of the Kohnstamm phenomenon (forearm flexion occurring shortly after the cessation of muscle contraction) in the contralateral arm and (ii) mirror vision had no effect. Indeed, the velocity of the Kohnstamm phenomenon tended to be adjusted to match the velocity of the passive displacement of the other arm. In a second experiment, arm displacement was simulated by vibrating the triceps at 25, 50 or 75 Hz. Results showed that the velocity of the Kohnstamm phenomenon in one arm increased with the vibration frequency applied to the other arm. Our results revealed the occurrence of bimanual coupling because involuntary displacement of one arm was regulated by muscle-related information generated by the actual or simulated displacement of the other arm. In line with the literature data on voluntary motor behavior, our study failed to evidence an additional impact of mirror vision on involuntary motor behavior. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Correlations of Handgrip Strength with Selected Hand-Arm-Anthropometric Variables in Indian Inter-university Female Volleyball Players

PubMed Central

Koley, Shyamal; Pal Kaur, Satinder

2011-01-01

Purpose The purpose of this study was to estimate the dominant handgrip strength and its correlations with some hand and arm anthropometric variables in 101 randomly selected Indian inter-university female volleyball players aged 18-25 years (mean age 20.52±1.40) from six Indian universities. Methods Three anthropometric variables, i.e. height, weight, BMI, two hand anthropometric variables, viz. right and left hand width and length, four arm anthropometric variables, i.e. upper arm length, lower arm length, upper extremity length, upper arm circumference and dominant right and non-dominant handgrip strength were measured among Indian inter-university female volleyball players by standard anthropometric techniques. Results The findings of the present study indicated that Indian female volleyball players had higher mean values in eleven variables and lesser mean values in two variables than their control counterparts, showing significant differences (P<0.032-0.001) in height (t=2.63), weight (t=8.66), left hand width (t=2.10), left and right hand length (t=9.99 and 10.40 respectively), right upper arm length (t=8.48), right forearm length (t=5.41), dominant (right) and non-dominant (left) handgrip strength (t=9.37 and 6.76 respectively). In female volleyball players, dominant handgrip strength had significantly positive correlations (P=0.01) with all the variables studied. Conclusion It may be concluded that dominant handgrip strength had strong positive correlations with all the variables studied in Indian inter-university female volleyball players. PMID:22375242

RECOVERY OF VASCULAR FUNCTION AFTER EXPOSURE TO A SINGLE BOUT OF SEGMENTAL VIBRATION

PubMed Central

Krajnak, Kristine; Waugh, Stacey; Miller, G. Roger; Johnson, Claud

2015-01-01

Work rotation schedules may be used to reduce the negative effects of vibration on vascular function. This study determined how long it takes vascular function to recover after a single exposure to vibration in rats (125 Hz, acceleration 5g). The responsiveness of rat-tail arteries to the vasoconstricting factor UK14304, an α2C-adrenoreceptor agonist, and the vasodilating factor acetylcholine (ACh) were measured ex vivo 1, 2, 7, or 9 d after exposure to a single bout of vibration. Vasoconstriction induced by UK14304 returned to control levels after 1 d of recovery. However, re-dilation induced by ACh did not return to baseline until after 9 d of recovery. Exposure to vibration exerted prolonged effects on peripheral vascular function, and altered vascular responses to a subsequent exposure. To optimize the positive results of work rotation schedules, it is suggested that studies assessing recovery of vascular function after exposure to a single bout of vibration be performed in humans. PMID:25072825

Syringomyelia

MedlinePlus

... are symptoms, they may include: Headache Loss of muscle mass ( wasting , atrophy), often in the arms and hands Spasms or tightness in the leg or hand and arm muscles Muscle function loss , loss of ability to use ...

The effect of 30 Hz vs. 50 Hz passive vibration and duration of vibration on skin blood flow in the arm.

PubMed

Maloney-Hinds, Colleen; Petrofsky, Jerrold Scott; Zimmerman, Grenith

2008-03-01

Recently, researchers have demonstrated that Whole Body Vibration (WBV) results in significant increases in skin blood flow (SBF). No study has determined if a specific frequency or a specific duration is better at optimizing SBF. Two studies were conducted to determine, 1) if there is a difference in SBF due to passive vibration of the forearm at 30 Hz vs. 50 Hz, 2) if one frequency is superior, and 3) if there is an optimal duration. In the first study, 18 subjects (mean age 20.3+/-2.9 years) were randomly placed into a 30 Hz or 50 Hz vibration group, and in the second, seven subjects (mean age 23.3+/-3.8 years) participated in both 30 and 50 Hz vibration. Each subject's arm was passively vibrated for 10 minutes. SBF was examined during vibration and for 15 minutes of recovery. Both frequencies produced significant increases in SBF (p<0.05) within the first four minutes of vibration. Peak SBFs were obtained by the fifth minute. SBF remained high for minutes 4 through 10 of vibration in the second study. In the first study, SBF remained high for minutes 4 through 9. During recovery, 30 Hz vibration produced SBFs below baseline values while 50 Hz SBFs remained above baseline. Statistically one frequency was not superior to the other. Five minutes of 30 Hz or 50 Hz vibration produced significant increases in SBF. Clinically, 50 Hz has additional benefits because SBF increased more rapidly and did not result in vasoconstriction during the recovery period. Future studies should be done to determine if these increases in SBF could be of benefit to populations with low circulation such as those with diabetes.

Quantification of Acute Vocal Fold Epithelial Surface Damage with Increasing Time and Magnitude Doses of Vibration Exposure

PubMed Central

Kojima, Tsuyoshi; Van Deusen, Mark; Jerome, W. Gray; Garrett, C. Gaelyn; Sivasankar, M. Preeti; Novaleski, Carolyn K.; Rousseau, Bernard

2014-01-01

Because the vocal folds undergo repeated trauma during continuous cycles of vibration, the epithelium is routinely susceptible to damage during phonation. Excessive and prolonged vibration exposure is considered a significant predisposing factor in the development of vocal fold pathology. The purpose of the present study was to quantify the extent of epithelial surface damage following increased time and magnitude doses of vibration exposure using an in vivo rabbit phonation model. Forty-five New Zealand white breeder rabbits were randomized to nine groups and received varying phonation time-doses (30, 60, or 120 minutes) and magnitude-doses (control, modal intensity phonation, or raised intensity phonation) of vibration exposure. Scanning electron microscopy and transmission electron microscopy was used to quantify the degree of epithelial surface damage. Results revealed a significant reduction in microprojection density, microprojection height, and depth of the epithelial surface with increasing time and phonation magnitudes doses, signifying increased epithelial surface damage risk with excessive and prolonged vibration exposure. Destruction to the epithelial cell surface may provide significant insight into the disruption of cell function following prolonged vibration exposure. One important goal achieved in the present study was the quantification of epithelial surface damage using objective imaging criteria. These data provide an important foundation for future studies of long-term tissue recovery from excessive and prolonged vibration exposure. PMID:24626217

Associations between anthropometric factors and peripheral neuropathy defined by vibrotactile perception threshold among industrial vibrating tool operators in Japan.

PubMed

Takemura, Shigeki; Yoshimasu, Kouichi; Tsuno, Kanami; Fukumoto, Jin; Kuroda, Mototsugu; Miyashita, Kazuhisa

2016-05-25

The effect of anthropometric factors on the fingertip vibrotactile perception threshold (VPT) of industrial vibrating tool operators (IVTOs) is not well known. The purpose of this study was to investigate the associations between anthropometric factors and fingertip VPT. We included for analysis two groups of IVTOs: Group 1, predominantly forestry workers (n=325); and Group 2, public servants (n=68). These IVTOs regularly received medical examinations to evaluate hand-arm vibration syndrome. In the examination, measurements of their fingertip VPTs were taken before and after cold-water immersion (10 minutes at 10°C for Group 1 and 5 minutes at 12°C for Group 2). Their body height and weight were measured to calculate the body mass index (BMI). The presence of peripheral neuropathy (PN) was defined as a VPT ≥17.5 dB at 10 minutes after finishing immersion. In the univariate analysis, weight and BMI were associated with a decreased risk of PN in both Groups 1 and 2. The negative association between BMI and PN remained in the multivariate analysis consistently, but weight reached marginal significance only in the multivariate analysis without BMI in both the groups. Age was positively associated with PN consistently in Group 1 but not in Group 2. Years exposed to vibration showed positive association with PN only in the univariate analysis of Group 1. Among IVTOs, factors reflecting body heat production, such as weight and BMI, were associated with a decreased risk of VPT-defined PN, regardless of the task engaged.

Postocclusive reactive hyperemia in hand-arm vibration syndrome.

PubMed

Stoyneva, Zlatka

2016-01-01

To assess laser Doppler-recorded postocclusive reactive hyperemic responses in vibration-induced Raynaud's phenomenon and compare it with primary and secondary to sclerodermy Raynaud's phenomenon. Thirty patients with vibration-induced Raynaud's phenomenon and 30 healthy controls and patients with primary and secondary to sclerodermy Raynaud's phenomenon were investigated. Fingerpulp skin blood flow was monitored by laser Doppler flowmetry during postocclusive reactive hyperemia test. Lower initial perfusion values were established in all the patients with Raynaud's phenomenon compared to the healthy controls (p < 0.0001). The postocclusive reactive hyperemic peak was lower in all the Raynaud's phenomenon groups compared to the controls (p < 0.0001). The postocclusive and basal perfusions were lower in the secondary Raynaud's phenomenon groups compared to the control and the primary Raynaud's phenomenon groups (p < 0.0001). The velocities to postocclusive hyperemic peak were lower in all the Raynaud's phenomenon patients (p < 0.0001), so were in the vibration-induced (p < 0.002) and the sclerodermy Raynaud's phenomenon (p < 0.004) groups in relation to the primary Raynaud's phenomenon group. The perfusion values and the velocities were significantly influenced by the initial superficial skin temperatures and perfusions, while the velocities were dependent also on gender, and the hyperemic peak on age. Postocclusive reactive hyperemia is abnormal in all Raynaud's phenomenon patients. Laser Doppler-recorded reactive hyperemia test contributes to diagnosing Raynaud's phenomenon and has proved to be valuable for group analysis. The applied method is not sensitive enough to discriminate adequately the type of Raynaud's phenomenon among individual cases. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

The effects of muscle vibration on anticipatory postural adjustments.

PubMed

Slijper, Harm; Latash, Mark L

2004-07-23

The current study investigated the influence of changes in sensory information related to postural stability on anticipatory postural adjustments (APAs) in standing subjects. Subjects performed fast arm movements and a load release task while standing on a stable force platform or on an unstable board. We manipulated sensory information through vibration of the Achilles tendons and additional finger touch (contact forces under 1 N). Changes in the background activity of leg, trunk, and arm muscles and displacements of the center of pressure (COP) were quantified within time intervals typical for APAs. In the arm movement task, leg and trunk muscles showed a significant drop in the APAs with finger touch, while the vibration and standing on the unstable board each led to an increase in the APA magnitude. In the load release task, ventral muscles decreased their APA activity with touch, while dorsal muscles showed increased inhibition during APAs. During vibration, dorsal and ventral muscles showed increased excitation and inhibition during APAs, respectively. An additional analysis of APAs at a joint level, has shown that in both tasks, an index related to the co-activation of agonist-antagonist muscle pairs (C-index) was modulated with touch, vibration, and stability particularly in leg muscles. Small changes in the other index related to reciprocal activation (R-index) were found only in trunk muscles. Light touch and vibration induced opposing changes in the C-index, suggesting their opposite effects on the stabilization of a reference point or vertical. We conclude that the central nervous system deploys patterns of adjustments in which increased co-contraction of distal muscles and reciprocal adjustments in trunk muscles are modified to ensure equilibrium under postural instability.

Effect of Attitudinal, Situational and Demographic Factors on Annoyance Due to Environmental Vibration and Noise from Construction of a Light Rapid Transit System.

PubMed

Wong-McSweeney, Daniel; Woodcock, James; Waddington, David; Peris, Eulalia; Koziel, Zbigniew; Moorhouse, Andy; Redel-Macías, María Dolores

2016-12-14

The aim of this paper is to determine what non-exposure factors influence the relationship between vibration and noise exposure from the construction of a Light Rapid Transit (LRT) system and the annoyance of nearby residents. Noise and vibration from construction sites are known to annoy residents, with annoyance increasing as a function of the magnitude of the vibration and noise. There is not a strong correlation between exposure and levels of annoyance suggesting that factors not directly related to the exposure may have an influence. A range of attitudinal, situational and demographic factors are investigated with the aim of understanding the wide variation in annoyance for a given vibration exposure. A face-to-face survey of residents ( n = 350) near three sites of LRT construction was conducted, and responses were compared to semi-empirical estimates of the internal vibration within the buildings. It was found that annoyance responses due to vibration were strongly influenced by two attitudinal variables, concern about property damage and sensitivity to vibration. Age, ownership of the property and the visibility of the construction site were also important factors. Gender, time at home and expectation of future levels of vibration had much less influence. Due to the measurement methods used, it was not possible to separate out the effects of noise and vibration on annoyance; as such, this paper focusses on annoyance due to vibration exposure. This work concludes that for the most cost-effective reduction of the impact of construction vibration and noise on the annoyance felt by a community, policies should consider attitudinal factors.

Effect of Attitudinal, Situational and Demographic Factors on Annoyance Due to Environmental Vibration and Noise from Construction of a Light Rapid Transit System

PubMed Central

Wong-McSweeney, Daniel; Woodcock, James; Waddington, David; Peris, Eulalia; Koziel, Zbigniew; Moorhouse, Andy; Redel-Macías, María Dolores

2016-01-01

The aim of this paper is to determine what non-exposure factors influence the relationship between vibration and noise exposure from the construction of a Light Rapid Transit (LRT) system and the annoyance of nearby residents. Noise and vibration from construction sites are known to annoy residents, with annoyance increasing as a function of the magnitude of the vibration and noise. There is not a strong correlation between exposure and levels of annoyance suggesting that factors not directly related to the exposure may have an influence. A range of attitudinal, situational and demographic factors are investigated with the aim of understanding the wide variation in annoyance for a given vibration exposure. A face-to-face survey of residents (n = 350) near three sites of LRT construction was conducted, and responses were compared to semi-empirical estimates of the internal vibration within the buildings. It was found that annoyance responses due to vibration were strongly influenced by two attitudinal variables, concern about property damage and sensitivity to vibration. Age, ownership of the property and the visibility of the construction site were also important factors. Gender, time at home and expectation of future levels of vibration had much less influence. Due to the measurement methods used, it was not possible to separate out the effects of noise and vibration on annoyance; as such, this paper focusses on annoyance due to vibration exposure. This work concludes that for the most cost-effective reduction of the impact of construction vibration and noise on the annoyance felt by a community, policies should consider attitudinal factors. PMID:27983662

Locomotor-Like Leg Movements Evoked by Rhythmic Arm Movements in Humans

PubMed Central

Sylos-Labini, Francesca; Ivanenko, Yuri P.; MacLellan, Michael J.; Cappellini, Germana; Poppele, Richard E.; Lacquaniti, Francesco

2014-01-01

Motion of the upper limbs is often coupled to that of the lower limbs in human bipedal locomotion. It is unclear, however, whether the functional coupling between upper and lower limbs is bi-directional, i.e. whether arm movements can affect the lumbosacral locomotor circuitry. Here we tested the effects of voluntary rhythmic arm movements on the lower limbs. Participants lay horizontally on their side with each leg suspended in an unloading exoskeleton. They moved their arms on an overhead treadmill as if they walked on their hands. Hand-walking in the antero-posterior direction resulted in significant locomotor-like movements of the legs in 58% of the participants. We further investigated quantitatively the responses in a subset of the responsive subjects. We found that the electromyographic (EMG) activity of proximal leg muscles was modulated over each cycle with a timing similar to that of normal locomotion. The frequency of kinematic and EMG oscillations in the legs typically differed from that of arm oscillations. The effect of hand-walking was direction specific since medio-lateral arm movements did not evoke appreciably leg air-stepping. Using externally imposed trunk movements and biomechanical modelling, we ruled out that the leg movements associated with hand-walking were mainly due to the mechanical transmission of trunk oscillations. EMG activity in hamstring muscles associated with hand-walking often continued when the leg movements were transiently blocked by the experimenter or following the termination of arm movements. The present results reinforce the idea that there exists a functional neural coupling between arm and legs. PMID:24608249

Factors affecting finger and hand pain in workers with HAVS.

PubMed

House, R; Krajnak, K; Jiang, D

2016-06-01

Pain and its management are important aspects of hand-arm vibration syndrome (HAVS). To determine the factors associated with finger and hand pain in workers with HAVS and, specifically, to assess the impact of several neurological variables as well as the vascular component of HAVS, grip strength and age. We assessed men with HAVS at a hospital occupational medicine clinic over 2 years. Subjects scored finger and hand pain separately using the Borg Scale (0-10). The possible predictors we evaluated included the Stockholm Neurological Scale (SNS) and Stockholm Vascular Scale (SVS) stages, current perception threshold (CPT), carpal tunnel syndrome (CTS), ulnar neuropathy, grip strength and age. We carried out nerve conduction testing to confirm the presence of CTS and ulnar neuropathy and measured CPT in the fingers at 2000 Hz, 250 Hz and 5 Hz corresponding to A-beta (large myelinated), A-delta (small myelinated) and C (unmyelinated) fibres, respectively. We calculated Spearman rank correlations to examine the relation between finger and hand pain and possible predictor variables. Among the 134 subjects, the median (25th-75th percentile) pain scores were 6 (4-8) for the fingers and 5 (1-7) for the hands. We found statistically significant correlations with finger pain for the SVS stage (r = 0.239; P < 0.01) and CTS (r = 0.184; P < 0.05). The only statistically significant correlation identified for hand pain was a negative correlation with grip strength (r = -0.185; P < 0.05). Management of finger and hand pain in HAVS should focus on the correlates we have identified. © The Author 2016. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Telerobotic control of a dextrous manipulator using master and six-DOF hand-controllers for space assembly and servicing tasks

NASA Technical Reports Server (NTRS)

O'Hara, John M.

1987-01-01

Two studies were conducted evaluating methods of controlling a telerobot; bilateral force reflecting master controllers and proportional rate six degrees of freedom (DOF) hand controllers. The first study compared the controllers on performance of single manipulator arm tasks, a peg-in-the-hole task, and simulated satellite orbital replacement unit changeout. The second study, a Space Station truss assembly task, required simultaneous operation of both manipulator arms (all 12 DOFs) and complex multiaxis slave arm movements. Task times were significantly longer and fewer errors were committed with the hand controllers. The hand controllers were also rated significantly higher in cognitive and manual control workload on the two-arm task. The master controllers were rated significantly higher in physical workload. There were no significant differences in ratings of manipulator control quality.

Aeroelastic instability stoppers for wind tunnel models

NASA Technical Reports Server (NTRS)

Doggett, R. V., Jr.; Ricketts, R. H. (Inventor)

1981-01-01

A mechanism for constraining models or sections thereof, was wind tunnel tested, deployed at the onset of aeroelastic instability, to forestall destructive vibrations in the model is described. The mechanism includes a pair of arms pivoted to the tunnel wall and straddling the model. Rollers on the ends of the arms contact the model, and are pulled together against the model by a spring stretched between the arms. An actuator mechanism swings the arms into place and back as desired.

[Clinical application of three-dimensional O-arm navigation system in treating patients with dystrophic scoliosis secondary to neurofibromatosis type Ⅰ].

PubMed

Liu, Z; Qiu, Y; Li, Y; Zhao, Z H; Wang, B; Zhu, F; Yu, Y; Sun, X; Zhu, Z Z

2017-03-01

Objective: To investigate the clinical outcomes and the accuracy of O-arm-navigation system assisted pedicle screw insertion in dystrophic scoliosis secondary to neurofibromatosis type Ⅰ(NF-1). Methods: A retrospective study was conducted in 41 patients with dystrophic NF-1-associated thoracic scoliosis who were surgically treated at Department of Orthopaedics, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School between June 2012 and October 2014 with more than 18 months follow-up. The patients were then divided into two groups: 18 patients were under the assistance of O-arm-navigation-based pedicle screw insertion (O-arm group) and the remaining 23 patients' pedicle screws insertion were conducted by free-hand (free-hand group). The X-ray and CT were analyzed to investigate the correction rate and safety of pedicle insertion. t -test was used to analyze measurement data and χ(2) test was used to analyze accuracy of screw insertion between the two groups. Results: The mean coronal Cobb angle was 63.2°±8.7° in the O-arm group and 66.9°±7.4° in the free-hand group ( P >0.05), which was then corrected into 23.1°±6.8° and 30.2°±7.6°( t =2.231, P =0.031) after surgery respectively.Operation time was (265.0±70.3)minutes and estimated blood loss was (1 024±465)ml in the O-arm group. Operation time and estimated blood loss was (243.0±49.6)minutes and (1 228±521)ml respectively in the free-hand group, which had no significant difference between the two groups. However, the implant density was higher in the O-arm group than that in the free-hand group ((64.1±10.8)% vs .(44.3±15.3)%)( t =4.652, P =0.000). The O-arm group comprised 122 screws, of which 72.9% were excellent, 22.1% were good and 4.9% were bad. The free-hand group comprised 136 screws and 48.5% of them were excellent, 33.8% were good and 17.6% were bad.Accuracy of pedicle screw insertion was higher in the O-arm group than that in the free-hand group(χ(2)=10.140, P <0.05). By June 2016, the average follow-up period was (20.9±3.4)months(ranging from18 to 26 months), including (20.3±3.1)months in the O-arm group and (21.4±5.5)months in the free-hand group. At last follow-up point, coronal correction loss was significantly higher in the free-hand group than that in the O-arm group (6.3°±2.6° vs . 4.4°±1.6°)( t =2.719, P =0.009). Conclusions: Compared with free-hand technique, O-arm-navigation technique could enhance accuracy of pedicle insertion and implant density of dystrophic region in dystrophic NF-1-associated scoliosis patients, which result in a better correction rate and less correction loss. Besides, the advantage of O-arm-navigation do not increase operative time and estimate blood loss.

Comparison of Annoyance from Railway Noise and Railway Vibration

PubMed Central

Gidlöf-Gunnarsson, Anita; Gustavsson, Sara

2017-01-01

The aim of this study is to compare vibration exposure to noise exposure from railway traffic in terms of equal annoyance, i.e., to determine when a certain noise level is equally annoying as a corresponding vibration velocity. Based on questionnaire data from the Train Vibration and Noise Effects (TVANE) research project from residential areas exposed to railway noise and vibration, the dose response relationship for annoyance was estimated. By comparing the relationships between exposure and annoyance for areas both with and without significant vibration exposure, the noise levels and vibration velocities that had an equal probability of causing annoyance was determined using logistic regression. The comparison gives a continuous mapping between vibration velocity in the ground and a corresponding noise level at the facade that are equally annoying. For equivalent noise level at the facade compared to maximum weighted vibration velocity in the ground the probability of annoyance is approximately 20% for 59 dB or 0.48 mm/s, and about 40% for 63 dB or 0.98 mm/s. PMID:28753921

Vibration safety limits for magnetic resonance elastography.

PubMed

Ehman, E C; Rossman, P J; Kruse, S A; Sahakian, A V; Glaser, K J

2008-02-21

Magnetic resonance elastography (MRE) has been demonstrated to have potential as a clinical tool for assessing the stiffness of tissue in vivo. An essential step in MRE is the generation of acoustic mechanical waves within a tissue via a coupled mechanical driver. Motivated by an increasing volume of human imaging trials using MRE, the objectives of this study were to audit the vibration amplitude of exposure for our IRB-approved human MRE studies, to compare these values to a conservative regulatory standard for vibrational exposure and to evaluate the applicability and implications of this standard for MRE. MRE displacement data were examined from 29 MRE exams, including the liver, brain, kidney, breast and skeletal muscle. Vibrational acceleration limits from a European Union directive limiting occupational exposure to whole-body and extremity vibrations (EU 2002/44/EC) were adjusted for time and frequency of exposure, converted to maximum displacement values and compared to the measured in vivo displacements. The results indicate that the vibrational amplitudes used in MRE studies are below the EU whole-body vibration limit, and the EU guidelines represent a useful standard that could be readily accepted by Institutional Review Boards to define standards for vibrational exposures for MRE studies in humans.

Vibration safety limits for magnetic resonance elastography

PubMed Central

Ehman, E C; Rossman, P J; Kruse, S A; Sahakian, A V; Glaser, K J

2010-01-01

Magnetic resonance elastography (MRE) has been demonstrated to have potential as a clinical tool for assessing the stiffness of tissue in vivo. An essential step in MRE is the generation of acoustic mechanical waves within tissue via a coupled mechanical driver. Motivated by an increasing volume of human imaging trials using MRE, the objectives of this study were to audit the vibration amplitude of exposure for our IRB-approved human MRE studies, to compare these values to a conservative regulatory standard for vibrational exposure, and to evaluate the applicability and implications of this standard for MRE. MRE displacement data were examined from 29 MRE exams, including the liver, brain, kidney, breast, and skeletal muscle. Vibrational acceleration limits from a European Union directive limiting occupational exposure to whole-body and extremity vibrations (EU 2002/44/EC) were adjusted for time and frequency of exposure, converted to maximum displacement values, and compared to the measured in vivo displacements. The results indicate that the vibrational amplitudes used in MRE studies are below the EU whole-body vibration limit and the EU guidelines represent a useful standard that could be readily accepted by Institutional Review Boards to define standards for vibrational exposures for MRE studies in humans. PMID:18263949

Mesh three-dimensional arm orthosis with built-in ultrasound physiotherapy system

NASA Astrophysics Data System (ADS)

Kashapova, R. M.; Kashapov, R. N.; Kashapova, R. S.

2017-09-01

The possibility of using the built-in ultrasound physiotherapy system of the hand orthosis is explored in the work. The individual mesh orthosis from nylon 12 was manufactured by the 3D prototyping method on the installation of selective laser sintering SLS SPro 60HD. The applied technology of three-dimensional scanning made it possible to obtain a model of the patient’s hand and on the basis of it to build a virtual model of the mesh frame. In the course of the research, the developed system of ultrasound exposure was installed on the orthosis and its tests were carried out. As a result, the acceleration of the healing process and the reduction in the time of wearing orthosis were found.

Dependence of palmar sweating response and central nervous system activity on the frequency of whole-body vibration.

PubMed

Ando, Hideo; Noguchi, Ryo

2003-06-01

This study was carried out to determine the effects of the frequency of whole-body vibration on palmar sweating response and the activity of the central sympathetic nervous system. Palmar sweating volume was measured on the right palm of six healthy men before and during 3 minutes of exposure to sinusoidal whole-body vibration at three different frequencies (16, 31.5, and 63 Hz). The whole-body vibration had a frequency-weighted, root mean square (rms) acceleration magnitude of 2.0 m/s2. As the index of the activated central sympathetic nervous system, saliva level of 3-methoxy-4-hydroxyphenylglycol (MHPG) was analyzed before and immediately after each vibration exposure. Each vibration frequency induced a palmar sweating response, that of 31.5 Hz being the largest. However, no significant difference was found between the three vibration conditions. Saliva MHPG increased in all the vibration exposures, and the largest change was observed at 31.5 Hz, the difference being significant. Acute exposure to whole-body vibration induced a palmar sweating response and activated the central sympathetic nervous system. The effects on the central nervous system were found to be dependent on the frequency of the vibration.

TIMING VARIABILITY OF REACH TRAJECTORIES IN LEFT VERSUS RIGHT HEMISPHERE STROKE

PubMed Central

Freitas, Sandra Maria Sbeghen Ferreira; Gera, Geetanjali; Scholz, John Peter

2011-01-01

This study investigated trajectory timing variability in right and left stroke survivors and healthy controls when reaching to a centrally located target under a fixed target condition or when the target could suddenly change position after reach onset. Trajectory timing variability was investigated with a novel method based on dynamic programming that identifies the steps required to time warp one trial’s acceleration time series to match that of a reference trial. Greater trajectory timing variability of both hand and joint motions was found for the paretic arm of stroke survivors compared to their non-paretic arm or either arm of controls. Overall, the non-paretic left arm of the LCVA group and the left arm of controls had higher timing variability than the non-paretic right arm of the RCVA group and right arm of controls. The shoulder and elbow joint warping costs were consistent predictors of the hand’s warping cost for both left and right arms only in the LCVA group, whereas the relationship between joint and hand warping costs was relatively weak in control subjects and less consistent across arms in the RCVA group. These results suggest that the left hemisphere may be more involved in trajectory timing, although the results may be confounded by skill differences between the arms in these right hand dominant participants. On the other hand, arm differences did not appear to be related to differences in targeting error. The paretic left arm of the RCVA exhibited greater trajectory timing variability than the paretic right arm of the LCVA group. This difference was highly correlated with the level of impairment of the arms. Generally, the effect of target uncertainty resulted in slightly greater trajectory timing variability for all participants. The results are discussed in light of previous studies of hemispheric differences in the control of reaching, in particular, left hemisphere specialization for temporal control of reaching movements. PMID:21920508

Normalisation of brain connectivity through compensatory behaviour, despite congenital hand absence.

PubMed

Hahamy, Avital; Sotiropoulos, Stamatios N; Henderson Slater, David; Malach, Rafael; Johansen-Berg, Heidi; Makin, Tamar R

2015-01-06

Previously we showed, using task-evoked fMRI, that compensatory intact hand usage after amputation facilitates remapping of limb representations in the cortical territory of the missing hand (Makin et al., 2013a). Here we show that compensatory arm usage in individuals born without a hand (one-handers) reflects functional connectivity of spontaneous brain activity in the cortical hand region. Compared with two-handed controls, one-handers showed reduced symmetry of hand region inter-hemispheric resting-state functional connectivity and corticospinal white matter microstructure. Nevertheless, those one-handers who more frequently use their residual (handless) arm for typically bimanual daily tasks also showed more symmetrical functional connectivity of the hand region, demonstrating that adaptive behaviour drives long-range brain organisation. We therefore suggest that compensatory arm usage maintains symmetrical sensorimotor functional connectivity in one-handers. Since variability in spontaneous functional connectivity in our study reflects ecological behaviour, we propose that inter-hemispheric symmetry, typically observed in resting sensorimotor networks, depends on coordinated motor behaviour in daily life.

Exposure to whole-body vibration and mechanical shock: a field study of quad bike use in agriculture.

PubMed

Milosavljevic, Stephan; McBride, David I; Bagheri, Nasser; Vasiljev, Radivoj M; Mani, Ramakrishnan; Carman, Allan B; Rehn, Borje

2011-04-01

The purpose of this study was to determine exposure to whole-body vibration (WBV) and mechanical shock in rural workers who use quad bikes and to explore how personal, physical, and workplace characteristics influence exposure. A seat pad mounted triaxial accelerometer and data logger recorded full workday vibration and shock data from 130 New Zealand rural workers. Personal, physical, and workplace characteristics were gathered using a modified version of the Whole Body Vibration Health Surveillance Questionnaire. WBVs and mechanical shocks were analysed in accordance with the International Standardization for Organization (ISO 2631-1 and ISO 2631-5) standards and are presented as vibration dose value (VDV) and mechanical shock (S(ed)) exposures. VDV(Z) consistently exceeded European Union (Guide to good practice on whole body vibration. Directive 2002/44/EC on minimum health and safety, European Commission Directorate General Employment, Social Affairs and Equal Opportunities. 2006) guideline exposure action thresholds with some workers exceeding exposure limit thresholds. Exposure to mechanical shock was also evident. Increasing age had the strongest (negative) association with vibration and shock exposure with body mass index (BMI) having a similar but weaker effect. Age, daily driving duration, dairy farming, and use of two rear shock absorbers created the strongest multivariate model explaining 33% of variance in VDV(Z). Only age and dairy farming combined to explain 17% of the variance for daily mechanical shock. Twelve-month prevalence for low back pain was highest at 57.7% and lowest for upper back pain (13.8%). Personal (age and BMI), physical (shock absorbers and velocity), and workplace characteristics (driving duration and dairy farming) suggest that a mix of engineered workplace and behavioural interventions is required to reduce this level of exposure to vibration and shock.

Development of piezoelectric bistable energy harvester based on buckled beam with axially constrained end condition for human motion

NASA Astrophysics Data System (ADS)

Eltanany, Ali M.; Yoshimura, Takeshi; Fujimura, Norifumi; Ebied, Mohamed R.; Ali, Mohamed G. S.

2017-10-01

In this study, we aim to examine the triggering force for an efficient snap-through solution of hand shaking vibrations of a piezoelectric bistable energy harvester. The proposed structure works at very low frequencies with nearly continuous periodic vibrations. The static characterizations are presented as well as the dynamic characterizations based on the phase diagrams of velocity vs displacement, voltage vs displacement, and voltage vs input acceleration. The mass attached to the bistable harvester plays an important role in determining the acceleration needed for the snap-through action, and the explanation for this role is complex because of mass dependence on frequency/amplitude vibration. Various hand shaking vibration tests are performed to demonstrate the advantage of the proposed structure in harvesting energy from hand shaking vibration. The minimum input acceleration for snap-through action was 11.59 m/s2 with peaks of 15.76 and 2 m/s2 in the frequency range of 1.3-2.7 Hz, when an attached mass of 14.6 g is used. The maximum generated power at a buckling state of 0.5 mm is 11.3 µW for the test structure at 26 g. The experimental results obtained in this study indicate that power output harvesting of slow hand shaking vibrations at 10 µW and a load resistance of 1 MΩ.

A phase I/pharmacokinetic study of sunitinib in combination with highly active antiretroviral therapy (HAART) in HIV-positive patients with cancer: AIDS Malignancy Consortium Trial AMC 061

PubMed Central

Rudek, Michelle A; Moore, Page C.; Mitsuyasu, Ronald T.; Dezube, Bruce J.; Aboulafia, David; Gerecitano, John; Sullivan, Ryan; Cianfrocca, Mary E.; Henry, David H.; Ratner, Lee; Haigentz, Missak; Dowlati, Afshin; Little, Richard F.; Ivy, S. Percy; Deeken, John F.

2014-01-01

Background Treatment of non-AIDS defining cancers (NADCs) may be complicated by drug interactions between highly active antiretroviral therapy (HAART) and chemotherapy. This trial is the first by the AIDS Malignancy Consortium assessing targeted therapies and HAART in HIV+ cancer patients (ClinicalTrials.gov NCT00890747). Methods Patients were stratified into two arms based on whether they were taking ritonavir, a potent CYP3A4 inhibitor, in a modified phase I study of sunitinib. Patients in arm 1 (non-ritonavir HAART) received standard sunitinib dosing (50mg/day). Arm 2 (ritonavir-based HAART) used a phase I, 3+3 dose escalation design (from 25 to 50mg/day). Cycles were with four weeks on treatment followed by a two week break (6 weeks total). Pharmacokinetics of sunitinib and its active metabolite (N-desethyl sunitinib) were assessed. Results Nineteen patients were enrolled and evaluable. Patients on Arm 1 tolerated treatment with one observed dose limiting toxicity (DLT). In Arm 2, a DLT was experienced at 37.5mg, and an additional 3 of 5 patients experienced grade 3 neutropenia, an uncommon toxicity of sunitinib. No patient had a response, but 10 had stable disease, including 8 with prolonged disease stability. Efavirenz, a potent inducer of CYP3A4, resulted in increased exposure of N-desethyl sunitinib, whereas ritonavir caused decreased exposure of the metabolite. Hand-foot syndrome was associated with higher steady-state trough concentrations of sunitinib. Conclusions Patients on non-ritonavir based HAART regimens tolerated standard dosing of sunitinib. Patients on ritonavir-based therapy treated with 37.5mg/day experienced higher toxicities. Dose reduction of sunitinib to 37.5mg may be warranted in patients on ritonavir. PMID:24474568

Reduction of the coupling vibration between the bending vibrators of the frequency-change-type two-axis acceleration sensor

NASA Astrophysics Data System (ADS)

Sugawara, Sumio; Sasaki, Yoshifumi; Kudo, Subaru

2018-07-01

The frequency-change-type two-axis acceleration sensor uses a cross-type vibrator consisting of four bending vibrators. When coupling vibration exists between these four bending vibrators, the resonance frequency of each vibrator cannot be adjusted independently. In this study, methods of reducing the coupling vibration were investigated by finite-element analysis. A method of adjusting the length of the short arm of each vibrator was proposed for reducing the vibration. When piezoelectric ceramics were bonded to the single-sided surface of the vibrator, the method was not sufficient. Thus, the ceramics with the same dimensions were bonded to double-sided surfaces. As a result, a marked reduction was obtained in this case. Also, the linearity of the sensor characteristics was significantly improved in a small acceleration range. Accordingly, it was clarified that considering the symmetry along the thickness direction of the vibrator is very important.

A Subcortical Oscillatory Network Contributes to Recovery of Hand Dexterity after Spinal Cord Injury

ERIC Educational Resources Information Center

Nishimura, Yukio; Morichika, Yosuke; Isa, Tadashi

2009-01-01

Recent studies have shown that after partial spinal-cord lesion at the mid-cervical segment, the remaining pathways compensate for restoring finger dexterity; however, how they control hand/arm muscles has remained unclear. To elucidate the changes in dynamic properties of neural circuits connecting the motor cortex and hand/arm muscles, we…

Contribution of individual components of a job cycle on overall severity of whole-body vibration exposure: a study in Indian mines.

PubMed

Mandal, Bibhuti B; Mansfield, Neil J

2016-01-01

Drivers of earth-moving machines are exposed to whole-body vibration (WBV). In mining operations there can be a combination of relatively high magnitudes of vibration and long exposure times. Effective risk mitigation requires understanding of the main aspects of a task that pose a hazard to health. There are very few published studies of WBV exposure from India. This paper reports on a study that considered the contribution of the component phases of dumper operations, on the overall vibration exposure of the drivers. It shows that vibration magnitudes are relatively high, and that haulage tasks are the main contributor to the exposure. It is recommended that driver speed, haul road surfaces and vehicle maintenance/selection are optimized to ensure minimization of vibration. If this is not sufficient, operation times might need to be reduced in order to ensure that the health guidance caution zone from Standard No. ISO 2631-1:1997 is not exceeded.

Interactive Design and Development of Real Arm Movements for Application in Rehabilitation

NASA Astrophysics Data System (ADS)

Rosman, Rafidah; Hadi, Muhammad Zaidan Abdul; Abu Bakar, Nurulliyana

2018-03-01

An interactive real arm movements for application in rehabilitation is designed and developed. The aim is to encourage hand paralysis patients performing their physical therapy by introducing games application in replacing conventional hand therapy module and methods. In this project, the accelerometer is used for tracking the orientation of the arm. As the arm moves, the values from x, y and z axis from the accelerometer changes and are being read by the Analog Inputs of the Arduino Board. After being read by the Analog Inputs of the Arduino Board, the 3D model moves as well. Solidworks software was used to modeled the hand in which the data is then transferred to Matlab/Simulink using SimMechanicalLink from Mathworks. Lastly, the sensor glove was programmed to work as a controller of games application in hand rehabilitation thus makes it an enjoyable therapy process.

Robot-Assisted Training of Arm and Hand Movement Shows Functional Improvements for Incomplete Cervical Spinal Cord Injury.

PubMed

Francisco, Gerard E; Yozbatiran, Nuray; Berliner, Jeffrey; OʼMalley, Marcia K; Pehlivan, Ali Utku; Kadivar, Zahra; Fitle, Kyle; Boake, Corwin

2017-10-01

The aim of the study was to demonstrate the feasibility, tolerability, and effectiveness of robotic-assisted arm training in incomplete chronic tetraplegia. Pretest/posttest/follow-up was conducted. Ten individuals with chronic cervical spinal cord injury were enrolled. Participants performed single degree-of-freedom exercise of upper limbs at an intensity of 3-hr per session for 3 times a week for 4 wks with MAHI Exo-II. Arm and hand function tests (Jebsen-Taylor Hand Function Test, Action Research Arm Test), strength of upper limb (upper limb motor score, grip, and pinch strength), and independence in daily living activities (Spinal Cord Independence Measure II) were performed at baseline, end of training, and 6 mos later. After 12 sessions of training, improvements in arm and hand functions were observed. Jebsen-Taylor Hand Function Test (0.14[0.04]-0.21[0.07] items/sec, P = 0.04), Action Research Arm Test (30.7[3.8]-34.3[4], P = 0.02), American Spinal Injury Association upper limb motor score (31.5[2.3]-34[2.3], P = 0.04) grip (9.7[3.8]-12[4.3] lb, P = 0.02), and pinch strength (4.5[1.1]-5.7[1.2] lb, P = 0.01) resulted in significant increases. Some gains were maintained at 6 mos. No change in Spinal Cord Independence Measure II scores and no adverse events were observed. Results from this pilot study suggest that repetitive training of arm movements with MAHI Exo-II exoskeleton is safe and has potential to be an adjunct treatment modality in rehabilitation of persons with spinal cord injury with mild to moderate impaired arm functions.

A comparative study on the CT effective dose for various positions of the patient's arm

NASA Astrophysics Data System (ADS)

Seong, Ji-Hye; Park, Soon-Ki; Kim, Jung-Sun; Jung, Woo-Young; Kim, Ho-Sung; Dong, Kyung-Rae; Chung, Woon-Kwan; Cho, Jae-Hwan; Cho, Young-Kuk

2012-10-01

In a whole body PET/CT (positron emission tomography/computed tomography) scan, lifting the patient's arm to improve the image quality is natural. On the other hand, the arms should be placed lower when the lesion is located in the head and neck. This study compared the CT effective dose for each arm position after applying AEC (automatic exposure control). Forty-five patients who had undergone an 18F-FDG (fluorine-18-fluoro deoxy glucose) whole body PET/CT scan were examined using Biograph Truepoint 40, Biograph Sensation 16, and Discovery STe 8 systems. The CT effective dose of 15 patients for each set of equipment was measured and analyzed comparatively in both the arm-lifted and arm-lowered positions. The ImPACT Ver. 1.0 program was used to measure the CT effective dose. A paired t-test (SPSS 18.0 statistic program) was applied for statistical analysis. In the case of the arm-lifted position, the CT effective dose measured for Biograph 40, Biograph 16, and DSTe 8 systems were 6.33 ± 0.93 mSv, 8.01 ± 1.34 mSv, and 9.69 ± 2.32 mSv, respectively. When the arms were located in the lower position, the respective CT effective doses were 6.97 ± 0.76 mSv, 8.95 ± 1.85 mSv, and 13.07 ± 2.87 mSv, respectively. These results revealed 9.2%, 10.5%, and 25.9% improvement in the CT effective doses for the Biograph 40, Biograph 16 and DSTe 8 systems, respectively, when the arms were raised compared to that when they were lowered (p < 0.05). For the whole body PET/CT case, the CT effective dose applying AEC showed a mean 15.2% decrease in the radiation exposure of the patients when the arm was lifted. The patient with no lesion in the head and neck would show fewer artifacts in the objective part and a lower CT effective dose. For a patient with a lesion in the head and neck, the artifacts in the objective part can be reduced by putting the arms down. The fact that the CT effective dose is increased in a whole-body PET/CT scan should be a concern.

Exposure to Upper Arm Elevation During Work Compared to Leisure Among 12 Different Occupations Measured with Triaxial Accelerometers.

PubMed

Palm, Peter; Gupta, Nidhi; Forsman, Mikael; Skotte, Jørgen; Nordquist, Tobias; Holtermann, Andreas

2018-06-26

Regarding prevention of neck and shoulder pain (NSP), unsupported arm elevation is one factor that should be taken into account when performing work risk assessment. Triaxial accelerometers can be used to measure arm elevation over several days but it is not possible to differentiate between supported and unsupported arm elevation from accelerometers only. Supported arm elevation is more likely to exist during sitting than standing. The aim of the study was to evaluate the use of whole workday measurements of arm elevation with accelerometers to assess potentially harmful work exposure of arm elevation, by comparing arm elevation at work with arm elevation during leisure, in a population with diverse work tasks, and to assess how the exposure parameters were modified when upper arm elevation during sitting time was excluded. The participants, 197 workers belonging to 12 occupational groups with diverse work tasks, wore triaxial accelerometers on the dominant arm, hip, and back for 1-4 days to measure arm elevation and periods of sitting. None of the groups were found to have higher exposure to arm elevation during work compared to leisure. Even though some occupations where known to have work tasks that forced them to work with elevated arms to a large extent. A high proportion of arm elevation derived from sitting time, especially so during leisure. When arm elevation during sitting time was excluded from the analysis, arm elevation was significantly higher at work than during leisure among construction workers, garbage collectors, manufacturing workers, and domestic cleaners. Together this illustrates that it is not suitable to use whole workday measurments of arm elevation with accelerometer as a sole information source when assessing the risk for NSP due to arm elevation. Information on body posture can provide relevant contextual information in exposure assessments when it is known that the potential harmful exposure is performed in standing or walking.

A prospective study of musculoskeletal outcomes among manufacturing workers: II. Effects of psychosocial stress and work organization factors.

PubMed

Gerr, Fredric; Fethke, Nathan B; Anton, Dan; Merlino, Linda; Rosecrance, John; Marcus, Michele; Jones, Michael P

2014-02-01

The aim of this study was to characterize associations between psychosocial and work organizational risk factors and upper-extremity musculoskeletal symptoms and disorders. Methodological limitations of previous studies of psychosocial and work organizational risk factors and musculoskeletal outcomes have produced inconsistent associations. In this prospective epidemiologic study of 386 workers, questionnaires to assess decision latitude ("control") and psychological job demands ("demand") were administered to study participants and were used to classify them into job strain "quadrants". Measures of job stress and job change were collected during each week of follow-up. Incident hand/arm and neck/shoulder symptoms and disorders were ascertained weekly. Associations between exposure measures and musculoskeletal outcomes were estimated with proportional hazard methods. When compared to the low-demand/high-control job strain referent category, large increases in risk of hand/arm disorders were observed for both high-demand/high-control (hazard ratio [HR] = 4.49, 95% confidence interval [CI] = [1.23, 16.4]) and high-demand/low-control job strain categories (HR = 5.18,95% CI = [1.39, 19.4]). Similar associations were observed for hand/arm symptoms. A strong association was also observed between the low-demand/low-control job strain category and neck/shoulder disorders (HR = 6.46, 95% CI = [1.46, 28.6]). Statistically significant associations were also observed between weekly stress level and weekly job change and several musculoskeletal outcomes. Associations between psychosocial risk factors and work organizational factors and musculoskeletal outcomes were large and in the hypothesized direction. Prevention of occupational musculoskeletal disorders may require attention to psychosocial and work organizational factors in addition to physical factors. Methods to control adverse effects of psychosocial and work organizational risk factors should be explored.

Hardware interface for isolation of vibrations in flexible manipulators: Development and applications

NASA Technical Reports Server (NTRS)

Manouchehri, Davoud; Lindsay, Thomas; Ghosh, David

1994-01-01

NASA's Langley Research Center (LaRC) is addressing the problem of isolating the vibrations of the Shuttle remote manipulator system (RMS) from its end-effector and/or payload by modeling an RMS flat-floor simulator with a dynamic payload. Analysis of the model can lead to control techniques that will improve the speed, accuracy, and safety of the RMS in capturing satellites and eventually facilitate berthing with the space station. Rockwell International Corporation, also involved in vibration isolation, has developed a hardware interface unit to isolate the end-effector from the vibrations of an arm on a Shuttle robotic tile processing system (RTPS). To apply the RTPS isolation techniques to long-reach arms like the RMS, engineers have modeled the dynamics of the hardware interface unit with simulation software. By integrating the Rockwell interface model with the NASA LaRC RMS simulator model, investigators can study the use of a hardware interface to isolate dynamic payloads from the RMS. The interface unit uses both active and passive compliance and damping for vibration isolation. Thus equipped, the RMS could be used as a telemanipulator with control characteristics for capture and berthing operations. The hardware interface also has applications in industry.

The 'Arm Force Field' method to predict manual arm strength based on only hand location and force direction.

PubMed

La Delfa, Nicholas J; Potvin, Jim R

2017-03-01

This paper describes the development of a novel method (termed the 'Arm Force Field' or 'AFF') to predict manual arm strength (MAS) for a wide range of body orientations, hand locations and any force direction. This method used an artificial neural network (ANN) to predict the effects of hand location and force direction on MAS, and included a method to estimate the contribution of the arm's weight to the predicted strength. The AFF method predicted the MAS values very well (r 2  = 0.97, RMSD = 5.2 N, n = 456) and maintained good generalizability with external test data (r 2  = 0.842, RMSD = 13.1 N, n = 80). The AFF can be readily integrated within any DHM ergonomics software, and appears to be a more robust, reliable and valid method of estimating the strength capabilities of the arm, when compared to current approaches. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of the vibration attenuation properties of an air-inflated cushion with two different heavy machinery seats in multi-axis vibration environments including jolts.

PubMed

Ji, Xiaoxu; Eger, Tammy R; Dickey, James P

2017-03-01

Seats and cushions can attenuate whole-body vibration (WBV) exposures and minimize health risks for heavy machine operators. We successfully developed neural network (NN) algorithms to identify the vibration attenuation properties for four different seating conditions (seat/cushion combinations), and implemented each of the NN models to predict the equivalent daily exposure A(8) values for various vehicles in the forestry and mining environments. We also evaluated the performance of the new prototype No-Jolt™ air-inflated cushion and the original cushion of each seat with jolt exposures. We observed that the air cushion significantly improved the vibration attenuation properties of the seat that initially had good performance, but not for the seat that had relatively poor vibration attenuation properties. In addition, operator's anthropometrics and sex influenced the performance of the air-inflated cushion when the vibration environment included jolt exposures. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Analysis of subjective symptoms of upper extremities in dental technicians].

PubMed

Yoshida, H; Nagata, C; Mirbod, S M; Iwata, H; Inaba, R

1991-01-01

Our review of the literature showed no report on the subjective symptoms of the upper extremities in dental technicians. This study was therefore undertaken on 164 dental technicians in Gifu Prefecture to investigate the relationship between the subjective symptoms of the hands, arms and shoulders and work of dental technicians. The following results were obtained. 1) The prevalence of Raynaud's phenomenon and numbness of the fingers was 5.5 and 18.5 %, respectively. A significant positive correlation was observed between the prevalence and frequency of numbness and cold sensation in the fingers and the daily usage time (h) of high-speed type machines. In addition, pain in the fingers and around the wrists, and pain and numbness in the arms were significantly related to the daily usage time (h) of low-speed type machines. These results suggest that the usage of high- and low-speed type machines may be a cause of vibration syndrome among dental technicians. 2) A high prevalence of pain in the shoulders (30.8%), neck (30.1%), and back (36.3%) was observed in dental technicians. It is considered that these symptoms are related to the working posture and usage of machines.

Investigation of a cantilever structured piezoelectric energy harvester used for wearable devices with random vibration input

NASA Astrophysics Data System (ADS)

Bai, Yang; Tofel, Pavel; Hadas, Zdenek; Smilek, Jan; Losak, Petr; Skarvada, Pavel; Macku, Robert

2018-06-01

The capability of using a linear kinetic energy harvester - A cantilever structured piezoelectric energy harvester - to harvest human motions in the real-life activities is investigated. The whole loop of the design, simulation, fabrication and test of the energy harvester is presented. With the smart wristband/watch sized energy harvester, a root mean square of the output power of 50 μW is obtained from the real-life hand-arm motion in human's daily life. Such a power is enough to make some low power consumption sensors to be self-powered. This paper provides a good and reliable comparison to those with nonlinear structures. It also helps the designers to consider whether to choose a nonlinear structure or not in a particular energy harvester based on different application scenarios.

The effects of whole body vibration on EMG activity of the upper extremity muscles in static modified push up position.

PubMed

Ashnagar, Zinat; Shadmehr, Azadeh; Hadian, Mohammadreza; Talebian, Saeed; Jalaei, Shohreh

2016-08-10

Whole Body Vibration (WBV) has been reported to change neuromuscular activity which indirectly assessed by electromyography (EMG). Although researches regarding the influence of WBV on EMG activity of the upper extremity muscles are in their infancy, contradictory findings have been reported as a result of dissimilar protocols. The purpose of this study was to investigate the effects of WBV on electromyography (EMG) activity of upper extremity muscles in static modified push up position. Forty recreationally active females were randomly assigned in WBV and control groups. Participants in WBV group received 5 sets of 30 seconds vibration at 5 mm (peak to peak) and 30 Hz by using vibratory platform. No vibration stimulus was used in the control group. Surface EMG was recorded from Upper Trapezius (UT), Serratus Anterior (SA), Biceps Brachii (BB) and Triceps Brachii (TB) muscles before, during and after the vibration protocol while the subjects maintained the static modified push up position. EMG signals were expressed as root mean square (EMGrms) and normalized by maximum voluntary exertion (MVE). EMGrms activity of the studied muscles increased significantly during the vibration protocol in the WBV group comparing to the control group (P ≤ 0.05). The results indicated that vibration stimulus transmitting via hands increased muscle activity of UT, SA, BB and TB muscles by an average of 206%, 60%, 106% and 120%, respectively, comparing to pre vibration values. These findings suggest that short exposure to the WBV could increase the EMGrms activity of the upper extremity muscles in the static modified push-up position. However, more sessions of WBV application require for a proper judgment.

Contralesional arm preference depends on hemisphere of damage and target location in unilateral stroke patients

PubMed Central

Mani, Saandeep; Przybyla, Andrzej; Good, David C.; Haaland, Kathleen Y.; Sainburg, Robert L.

2014-01-01

Background Previous research has shown that during simulated activities of daily living right handed stroke patients use their contralesional arm more after left than right hemisphere stroke. These findings were attributed to a hand preference effect. However, these decisions about when to use the contralesional arm may be modulated by where in the work space the task is performed, a factor that could be used in physical rehabilitation to influence recovery by decreasing learned non-use. Objective To examine how target location and side of stroke influences arm selection choices for simple reaching movements. Methods Fourteen right-handed stroke patients (7 with left hemisphere damage, 7 with right hemisphere damage) with similar degree of hemiparesis (Fugl-Meyer motor score), and 16 right-handed control subjects participated in this experiment. Thirty-two targets were presented throughout the reachable horizontal plane workspace in a pseudo-random fashion, and the subjects were asked to select one hand to reach the target on each trial. Results The left hemisphere damaged group chose their contralesional arm significantly more often than the right hemisphere damaged group. Patients with right hemisphere damage also chose their left (contralesional) arm significantly less than the control group. However, these patterns of choice were most pronounced in the center of the workspace. Conclusion Both the side of hemisphere damage and workspace location played a significant role in the choice of whether to use the contralesional arm for reaching. These findings have implications for structuring rehabilitation for unilateral stroke patients. PMID:24523143

Whole body vibration exposure patterns in Canadian prairie farmers.

PubMed

Zeng, Xiaoke; Kociolek, Aaron M; Khan, Muhammad Idrees; Milosavljevic, Stephan; Bath, Brenna; Trask, Catherine

2017-08-01

Whole body vibration is a significant physical risk factor associated with low back pain. This study assessed farmers' exposure to whole body vibration on the Canadian prairies according to ISO 2631-1. Eighty-seven vibration measurements were collected with a triaxial accelerometer embedded in a rubber seat pad at the operator-seat interface of agricultural machinery, including tractors, combines, pickup trucks, grain trucks, sprayers, swathers, all-terrain vehicles, and skid steers. Whole body vibration was highest in the vertical axis, with a mean (range) frequency-weighted root mean squared acceleration of 0.43 m/s 2 (0.19-1.06 m/s 2 ). Mean crest factors exceeded 9 in all 3 axes, indicating high mechanical shock content. The vertical axis vibration dose value was 7.55 m/s 1.75 (2.18-37.59 m/s 1.75 ), with 41.4% of measurements within or above the health guidance caution zone. These high exposures in addition to an ageing agricultural workforce may increase health risks even further, particularly for the low back. Practitioner Summary: Agricultural workers are frequently exposed to whole body vibration while operating farm equipment, presenting a substantial risk to musculoskeletal health including the low back. Assessing vibration exposure is critical in promoting a safe occupational environment, and may inform interventions to reduce farmer's exposure to vibration.

Mechanisms mediating vibration-induced chronic musculoskeletal pain analyzed in the rat.

PubMed

Dina, Olayinka A; Joseph, Elizabeth K; Levine, Jon D; Green, Paul G

2010-04-01

While occupational exposure to vibration is a common cause of acute and chronic musculoskeletal pain, eliminating exposure produces limited symptomatic improvement, and reexposure precipitates rapid recurrence or exacerbation. To evaluate mechanisms underlying these pain syndromes, we have developed a model in the rat, in which exposure to vibration (60-80Hz) induces, in skeletal muscle, both acute mechanical hyperalgesia as well as long-term changes characterized by enhanced hyperalgesia to a proinflammatory cytokine or reexposure to vibration. Exposure of a hind limb to vibration-produced mechanical hyperalgesia measured in the gastrocnemius muscle of the exposed hind limb, which persisted for approximately 2 weeks. When nociceptive thresholds had returned to baseline, exposure to a proinflammatory cytokine or reexposure to vibration produced markedly prolonged hyperalgesia. The chronic prolongation of vibration- and cytokine-hyperalgesia was prevented by spinal intrathecal injection of oligodeoxynucleotide (ODN) antisense to protein kinase Cepsilon, a second messenger in nociceptors implicated in the induction and maintenance of chronic pain. Vibration-induced hyperalgesia was inhibited by spinal intrathecal administration of ODN antisense to receptors for the type-1 tumor necrosis factor-alpha (TNFalpha) receptor. Finally, in TNFalpha-pretreated muscle, subsequent vibration-induced hyperalgesia was markedly prolonged. These studies establish a model of vibration-induced acute and chronic musculoskeletal pain, and identify the proinflammatory cytokine TNFalpha and the second messenger protein kinase Cepsilon as targets against which therapies might be directed to prevent and/or treat this common and very debilitating chronic pain syndrome. Copyright 2010 American Pain Society. All rights reserved.

Comparison of Radiation Exposure during Endovascular Treatment of Peripheral Arterial Disease with Flat-Panel Detectors on Mobile C-arm versus Fixed Systems.

PubMed

Guillou, Marie; Maurel, Blandine; Necib, Hatem; Vent, Pierre-Alexandre; Costargent, Alain; Chaillou, Philippe; Gouëffic, Yann; Kaladji, Adrien

2018-02-01

Flat-panel detectors on mobile C-arm (MC-arm) systems are currently challenging fixed C-arm (FC-arm) systems used in hybrid operating rooms. MC-arm systems offer an alternative to FC-arm systems in the endovascular treatment of peripheral arterial disease (PAD) but their efficiency has not been evaluated comparatively. Two series of patients undergoing arteriography with intention to treat were included. Each series consisted of 2 nonrandomized groups: an MC-arm group and an FC-arm group. Series 1 evaluated exposure to the patient (MC-arm, n = 113; FC-arm, n = 206) while series 2 evaluated exposure to patients and also health care personnel (MC-arm, n = 24; FC-arm, n = 76). The primary end points for evaluating exposure were air kerma (AK, in mGy) for patients and effective dose for health care personnel (in μSv). After adjustment for the effect of body mass index (analysis of covariance test), AK was found to be lower in the MC-arm group than in the FC-arm group (124.1 ± 142 vs. 173.3 ± 248.7, P = 0.025). There was no difference between the groups with regard to effective dose recorded for senior surgeons or for operating room nurses. However, a higher effective dose was recorded by the MC-arm group external dosimeter for the trainee resident and for nurse anesthetists. In endovascular treatment of lower limb PAD, use of an FC-arm system is associated with more radiation exposure to the patient than an MC-arm system. However, this type of imaging system does not appear to affect exposure to health care personnel. Copyright © 2017 Elsevier Inc. All rights reserved.

Evaluation of haptic interfaces for simulation of drill vibration in virtual temporal bone surgery.

PubMed

Ghasemloonia, Ahmad; Baxandall, Shalese; Zareinia, Kourosh; Lui, Justin T; Dort, Joseph C; Sutherland, Garnette R; Chan, Sonny

2016-11-01

Surgical training is evolving from an observership model towards a new paradigm that includes virtual-reality (VR) simulation. In otolaryngology, temporal bone dissection has become intimately linked with VR simulation as the complexity of anatomy demands a high level of surgeon aptitude and confidence. While an adequate 3D visualization of the surgical site is available in current simulators, the force feedback rendered during haptic interaction does not convey vibrations. This lack of vibration rendering limits the simulation fidelity of a surgical drill such as that used in temporal bone dissection. In order to develop an immersive simulation platform capable of haptic force and vibration feedback, the efficacy of hand controllers for rendering vibration in different drilling circumstances needs to be investigated. In this study, the vibration rendering ability of four different haptic hand controllers were analyzed and compared to find the best commercial haptic hand controller. A test-rig was developed to record vibrations encountered during temporal bone dissection and a software was written to render the recorded signals without adding hardware to the system. An accelerometer mounted on the end-effector of each device recorded the rendered vibration signals. The newly recorded vibration signal was compared with the input signal in both time and frequency domains by coherence and cross correlation analyses to quantitatively measure the fidelity of these devices in terms of rendering vibrotactile drilling feedback in different drilling conditions. This method can be used to assess the vibration rendering ability in VR simulation systems and selection of ideal haptic devices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of vertical active vibration isolation on tracking performance and on ride qualities

NASA Technical Reports Server (NTRS)

Dimasi, F. P.; Allen, R. E.; Calcaterra, P. C.

1972-01-01

An investigation to determine the effect on pilot performance and comfort of an active vibration isolation system for a commercial transport pilot seat is reported. The test setup consisted of: a hydraulic shaker which produced random vertical vibration inputs; the active vibration isolation system; the pilot seat; the pilot control wheel and column; the side-arm controller; and a two-axis compensatory tracking task. The effects of various degrees of pilot isolation on short-term (two-minute) tracking performance and comfort were determined.

Vibration Analysis and the Accelerometer

ERIC Educational Resources Information Center

Hammer, Paul

2011-01-01

Have you ever put your hand on an electric motor or motor-driven electric appliance and felt it vibrate? Ever wonder why it vibrates? What is there about the operation of the motor, or the object to which it is attached, that causes the vibrations? Is there anything "regular" about the vibrations, or are they the result of random causes? In this…

Effort, success, and nonuse determine arm choice

PubMed Central

Xiao, Yupeng; Kim, Sujin; Yoshioka, Toshinori; Gordon, James; Osu, Rieko

2015-01-01

How do humans choose one arm or the other to reach single targets in front of the body? Current theories of reward-driven decisionmaking predict that choice results from a comparison of “action values,” which are the expected rewards for possible actions in a given state. In addition, current theories of motor control predict that in planning arm movements, humans minimize an expected motor cost that balances motor effort and endpoint accuracy. Here, we test the hypotheses that arm choice is determined by comparison of action values comprising expected effort and expected task success for each arm, as well as a handedness bias. Right-handed subjects, in either a large or small target condition, were first instructed to use each hand in turn to shoot through an array of targets and then to choose either hand to shoot through the same targets. Effort was estimated via inverse kinematics and dynamics. A mixed-effects logistic-regression analysis showed that, as predicted, both expected effort and expected success predicted choice, as did arm use in the preceding trial. Finally, individual parameter estimation showed that the handedness bias correlated with mean difference between right- and left-arm success, leading to overall lower use of the left arm. We discuss our results in light of arm nonuse in individuals' poststroke. PMID:25948869

Whole-body vibration exposure of occupational horseback riding in agriculture: A ranching example.

PubMed

Zeng, Xiaoke; Trask, Catherine; Kociolek, Aaron M

2017-02-01

Horse riding is common in many occupations; however, there is currently no research evaluating exposure to whole-body vibration and mechanical shock on horseback. Whole-body vibration was measured on a cattle rancher during two 30 min horseback rides using a tri-axial accelerometer mounted on a western saddle. Vibration was summarized into standardized metrics, including the 8 hr equivalent root-mean-squared acceleration (A[8]) and the daily 4th power vibration dose value (VDV). The resulting exposures were compared to the exposure limit and action values provided by European Union Directive 2002/44/EC. The highest vibration for both rides was in the vertical axis, with average A(8) and VDV of 0.56 m/s 2 and 26.24 m/s 1.75 , respectively. The A(8) value indicated moderate risk while the VDV suggested high risk of harmful health effects. Exposure to whole-body vibration and mechanical shock during occupational horseback riding may pose deleterious health risks and increased susceptibility to low back pain. Am. J. Ind. Med. 60:215-220, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Change of a motor synergy for dampening hand vibration depending on a task difficulty.

PubMed

Togo, Shunta; Kagawa, Takahiro; Uno, Yoji

2014-10-01

The present study investigated the relationship between the number of usable degrees of freedom (DOFs) and joint coordination during a human-dampening hand vibration task. Participants stood on a platform generating an anterior-posterior directional oscillation and held a water-filled cup. Their usable DOFs were changed under the following conditions of limb constraint: (1) no constraint; (2) ankle constrained; and (3) ankle-knee constrained. Kinematic whole-body data were recorded using a three-dimensional position measurement system. The jerk of each body part was evaluated as an index of oscillation intensity. To quantify joint coordination, an uncontrolled manifold (UCM) analysis was applied and the variance of joints related to hand jerk divided into two components: a UCM component that did not affect hand jerk and an orthogonal (ORT) component that directly affected hand jerk. The results showed that hand jerk when the task used a cup filled with water was significantly smaller than when a cup containing stones was used, regardless of limb constraint condition. Thus, participants dampened their hand vibration utilizing usable joint DOFs. According to UCM analysis, increasing the oscillation velocity and the decrease in usable DOFs by the limb constraints led to an increase of total variance of the joints and the UCM component, indicating that a synergy-dampening hand vibration was enhanced. These results show that the variance of usable joint DOFs is more fitted to the UCM subspace when the joints are varied by increasing the velocity and limb constraints and suggest that humans adopt enhanced synergies to achieve more difficult tasks.

Feasibility study into self-administered training at home using an arm and hand device with motivational gaming environment in chronic stroke.

PubMed

Nijenhuis, Sharon M; Prange, Gerdienke B; Amirabdollahian, Farshid; Sale, Patrizio; Infarinato, Francesco; Nasr, Nasrin; Mountain, Gail; Hermens, Hermie J; Stienen, Arno H A; Buurke, Jaap H; Rietman, Johan S

2015-10-09

Assistive and robotic training devices are increasingly used for rehabilitation of the hemiparetic arm after stroke, although applications for the wrist and hand are trailing behind. Furthermore, applying a training device in domestic settings may enable an increased training dose of functional arm and hand training. The objective of this study was to assess the feasibility and potential clinical changes associated with a technology-supported arm and hand training system at home for patients with chronic stroke. A dynamic wrist and hand orthosis was combined with a remotely monitored user interface with motivational gaming environment for self-administered training at home. Twenty-four chronic stroke patients with impaired arm/hand function were recruited to use the training system at home for six weeks. Evaluation of feasibility involved training duration, usability and motivation. Clinical outcomes on arm/hand function, activity and participation were assessed before and after six weeks of training and at two-month follow-up. Mean System Usability Scale score was 69 % (SD 17 %), mean Intrinsic Motivation Inventory score was 5.2 (SD 0.9) points, and mean training duration per week was 105 (SD 66) minutes. Median Fugl-Meyer score improved from 37 (IQR 30) pre-training to 41 (IQR 32) post-training and was sustained at two-month follow-up (40 (IQR 32)). The Stroke Impact Scale improved from 56.3 (SD 13.2) pre-training to 60.0 (SD 13.9) post-training, with a trend at follow-up (59.8 (SD 15.2)). No significant improvements were found on the Action Research Arm Test and Motor Activity Log. Remotely monitored post-stroke training at home applying gaming exercises while physically supporting the wrist and hand showed to be feasible: participants were able and motivated to use the training system independently at home. Usability shows potential, although several usability issues need further attention. Upper extremity function and quality of life improved after training, although dexterity did not. These findings indicate that home-based arm and hand training with physical support from a dynamic orthosis is a feasible tool to enable self-administered practice at home. Such an approach enables practice without dependence on therapist availability, allowing an increase in training dose with respect to treatment in supervised settings. This study has been registered at the Netherlands Trial Registry (NTR): NTR3669 .

The preliminary effect of whole-body vibration intervention on improving the skeletal muscle mass index, physical fitness, and quality of life among older people with sarcopenia.

PubMed

Chang, Shu-Fang; Lin, Pei-Chen; Yang, Rong-Sen; Yang, Rea-Jeng

2018-01-17

Studies have shown that sarcopenia easily leads to difficulty moving, disability, and poor quality of life. However, researches on the use of whole-body vibration for older adults with sarcopenia living in institutions have been lacking. Therefore, the main objective of the present study was to investigate the effect of whole-body vibration intervention on improving the skeletal muscle mass index, physical fitness, and quality of life of older adults with sarcopenia living in institutions. This study adopted a quasi-experimental, single-group, pretest-posttest design. The whole-body vibration intervention was performed over a 3-month period, in which the older adults trained 3 times per week; each training lasted 60 s with a break of 30 s for 10 repetitions. The older adults' skeletal muscle mass index, physical fitness and quality of life before and after the intervention of the whole-body vibration was collected. Concerning the statistical methods adopted, nonparametric method-based tests were employed. According to the results of analysis, after the intervention of the 12-week whole-body vibration, the skeletal muscle mass index (z = - 3.621, p = 0.000), physical fitness on standing on one foot (z = - 2.447, p = 0.014), shoulder-arm flexibility (z = - 3.159, p = 0.002), 8-ft up and go test (z = - 2.692, p = 0.009), hand grip strength (z = - 3.388, p = 0.009), and five repeated sit-to-stand tests (z = - 2.936, p = 0.003), all improved significantly. Furthermore, concerning the quality of life of the older adults in the pretest and posttest, the improvements were statistically significant (z = - 2.533, p = 0.011). The study results showed the effect of whole-body vibration intervention on improving the skeletal muscle mass index, physical fitness, and quality of life of sarcopenic older people living in institutions and could serve as a crucial reference to health care professionals.

Effects of task-oriented robot training on arm function, activity, and quality of life in chronic stroke patients: a randomized controlled trial.

PubMed

Timmermans, Annick A A; Lemmens, Ryanne J M; Monfrance, Maurice; Geers, Richard P J; Bakx, Wilbert; Smeets, Rob J E M; Seelen, Henk A M

2014-03-31

Over fifty percent of stroke patients experience chronic arm hand performance problems, compromising independence in daily life activities and quality of life. Task-oriented training may improve arm hand performance after stroke, whereby augmented therapy may lead to a better treatment outcome. Technology-supported training holds opportunities for increasing training intensity. However, the effects of robot-supported task-oriented training with real life objects in stroke patients are not known to date. The aim of the present study was to investigate the effectiveness and added value of the Haptic Master robot combined with task-oriented arm hand training in chronic stroke patients. In a single-blind randomized controlled trial, 22 chronic stroke patients were randomly allocated to receive either task-oriented robot-assisted arm-hand training (experimental group) or task-oriented non-robotic arm-hand training (control group). For training, the T-TOAT (Technology-supported Task-Oriented Arm Training) method was applied. Training was provided during 8 weeks, 4 times/week, 2 × 30 min/day. A significant improvement after training on the Action Research Arm Test (ARAT) was demonstrated in the experimental group (p = 0.008). Results were maintained until 6 months after cessation of the training. On the perceived performance measure (Motor Activity Log (MAL)), both, the experimental and control group improved significantly after training (control group p = 0.008; experimental group p = 0.013). The improvements on MAL in both groups were maintained until 6 months after cessation of the training. With regard to quality of life, only in the control group a significant improvement after training was found (EuroQol-5D p = 0.015, SF-36 physical p = 0.01). However, the improvement on SF-36 in the control group was not maintained (p = 0.012). No between-group differences could be demonstrated on any of the outcome measures. Arm hand performance improved in chronic stroke patients, after eight weeks of task oriented training. The use of a Haptic Master robot in support of task-oriented arm training did not show additional value over the video-instructed task-oriented exercises in highly functional stroke patients. Current Controlled Trials ISRCTN82787126.

Dynamic Analysis of a Two Member Manipulator Arm

NASA Technical Reports Server (NTRS)

McGinley, Mark; Shen, Ji Y.

1997-01-01

Attenuating start-up and stopping vibrations when maneuvering large payloads attached to flexible manipulator systems is a great concern for many space missions. To address this concern, it was proposed that the use of smart materials, and their applications in smart structures, may provide an effective method of control for aerospace structures. In this paper, a modified finite element model has been developed to simulate the performance of piezoelectric ceramic actuators, and was applied to a flexible two-arm manipulator system. Connected to a control voltage, the piezoelectric actuators produce control moments based on the optimal control theory. The computer simulation modeled the end-effector vibration suppression of the NASA manipulator testbed for berthing operations of the Space Shuttle to the Space Station. The results of the simulation show that the bonded piezoelectric actuators can effectively suppress follow-up vibrations of the end-effector, stimulated by some external disturbance.

Study of design and control of remote manipulators. Part 2: Vibration considerations in manipulator design

NASA Technical Reports Server (NTRS)

Book, W. J.

1973-01-01

An investigation is reported involving a mathematical procedure using 4 x 4 transformation matrices for analyzing the vibrations of flexible manipulators. Previous studies with the procedure are summarized and the method is extended to include flexible joints as well as links, and to account for the effects of various power transmission schemes. A systematic study of the allocation of structural material and the placement of components such as motors and gearboxes was undertaken using the analytical tools developed. As one step in this direction the variables which relate the vibration parameters of the arm to the task and environment of the arm were isolated and nondimensionalized. The 4 x 4 transformation matrices were also used to develop analytical expressions for the terms of the complete 6 x 6 compliance matrix for the case of two flexible links joined by a rotating joint, flexible about its axis of rotation.

The Effects of Unit Exercises on the Hand Grip Strength of Arm Wrestlers

ERIC Educational Resources Information Center

Yonca, Sezer S.; Engin, Çelikel B.; Serdar, Yücel A.; Mustafa, Karadag; Yüksel, Savucu

2017-01-01

The aim of this research is to evaluate the change in the hand grip strength of the male arm wrestlers before and after a unit of exercise. The participants of the research consist of sportsmen (n=16) of Firat University arm wrestling team in 18-25 age group. Within the scope of the research, all of the tests and measurements (age, length, body…

The relation of hand and arm configuration variances while tracking geometric figures in Parkinson's disease: aspects for rehabilitation.

PubMed

Keresztényi, Zoltán; Cesari, Paola; Fazekas, Gábor; Laczkó, József

2009-03-01

Variances of drawing arm movements between patients with Parkinson's disease and healthy controls were compared. The aim was to determine whether differences in joint synergies or individual joint rotations affect the endpoint (hand position) variance. Joint and endpoint coordinates were measured while participants performed drawing tasks. Variances of arm configurations and endpoints were computed and statistically analyzed for 12 patients and 12 controls. The variance of arm movements for patients (both for arm configuration and endpoint) was overall higher than that for the control group. Variation was smaller for drawing a circle versus a square and for drawing with the dominant versus the nondominant hand within both groups. The ratio of arm configuration variances between groups was similar to the ratio of endpoint variances. There were significant differences in the velocity, but not in the path lengths of movements comparing the two groups. Patients presented less movement stability while drawing different figures in different trials. Moreover, the similarity of the ratios suggests that the ill-coordinated hand movement was caused by the error in the movements of individual body parts rather than by the lack of intersegmental coordination. Thus, rehabilitation may focus on the improvement of the precision of individual joint rotations.

Fingertip contact suppresses the destabilizing influence of leg muscle vibration

NASA Technical Reports Server (NTRS)

Lackner, J. R.; Rabin, E.; DiZio, P.

2000-01-01

Touch of the hand with a stationary surface at nonmechanically supportive force levels (<1 N) greatly attenuates postural sway during quiet stance. We predicted such haptic contact would also suppress the postural destabilization caused by vibrating the right peroneus brevis and longus muscles of subjects standing heel-to-toe with eyes closed. In experiment 1, ten subjects were tested under four conditions: no-vibration, no-touch; no-vibration, touch; vibration, no-touch; and vibration, touch. A hand-held physiotherapy vibrator (120 Hz) was applied approximately 5 cm above the malleolous to stimulate the peroneus longus and brevis tendons. Touch conditions involved contact of the right index finger with a laterally positioned surface (<1 N of force) at waist height. Vibration in the absence of finger contact greatly increased the mean sway amplitude of the center of pressure and of the head relative to the no-vibration, no-touch control condition (P < 0.001). The touch, no-vibration and touch-vibration conditions were not significantly different (P > 0.05) from each other and both had significantly less mean sway amplitude of head and of center of pressure than the other conditions (P < 0.01). In experiment 2, eight subjects stood heel-to-toe under touch and no-touch conditions involving 40-s duration trials of peroneus tendon vibration at different duty cycles: 1-, 2-, 3-, and 4-s ON and OFF periods. The vibrator was attached to the subject's leg and remotely activated. In the no-touch conditions, subjects showed periodic postural disruptions contingent on the duty cycle and mirror image rebounds with the offset of vibration. In the touch conditions, subjects were much less disrupted and showed compensations occurring within 500 ms of vibration onset and mirror image rebounds with vibration offset. Subjects were able to suppress almost completely the destabilizing influence of the vibration in the 3- and 4-s duty cycle trials. These experiments show that haptic contact of the hand with a stable surface can suppress abnormal proprioceptive and motor signals in leg muscles.

Associations between workplace factors and carpal tunnel syndrome: A multi-site cross sectional study.

PubMed

Fan, Z Joyce; Harris-Adamson, Carisa; Gerr, Fred; Eisen, Ellen A; Hegmann, Kurt T; Bao, Stephen; Silverstein, Barbara; Evanoff, Bradley; Dale, Ann Marie; Thiese, Matthew S; Garg, Arun; Kapellusch, Jay; Burt, Susan; Merlino, Linda; Rempel, David

2015-05-01

Few large epidemiologic studies have used rigorous case criteria, individual-level exposure measurements, and appropriate control for confounders to examine associations between workplace psychosocial and biomechanical factors and carpal tunnel syndrome (CTS). Pooling data from five independent research studies, we assessed associations between prevalent CTS and personal, work psychosocial, and biomechanical factors while adjusting for confounders using multivariable logistic regression. Prevalent CTS was associated with personal factors of older age, obesity, female sex, medical conditions, previous distal upper extremity disorders, workplace measures of peak forceful hand activity, a composite measure of force and repetition (ACGIH Threshold Limit Value for Hand Activity Level), and hand vibration. In this cross-sectional analysis of production and service workers, CTS prevalence was associated with workplace and biomechanical factors. The findings were similar to those from a prospective analysis of the same cohort with differences that may be due to recall bias and other factors. © 2015 Wiley Periodicals, Inc.

Endoscopic endonasal transsphenoidal surgery using the iArmS operation support robot: initial experience in 43 patients.

PubMed

Ogiwara, Toshihiro; Goto, Tetsuya; Nagm, Alhusain; Hongo, Kazuhiro

2017-05-01

Objective The intelligent arm-support system, iArmS, which follows the surgeon's arm and automatically fixes it at an adequate position, was developed as an operation support robot. iArmS was designed to support the surgeon's forearm to prevent hand trembling and to alleviate fatigue during surgery with a microscope. In this study, the authors report on application of this robotic device to endoscopic endonasal transsphenoidal surgery (ETSS) and evaluate their initial experiences. Methods The study population consisted of 43 patients: 29 with pituitary adenoma, 3 with meningioma, 3 with Rathke's cleft cyst, 2 with craniopharyngioma, 2 with chordoma, and 4 with other conditions. All patients underwent surgery via the endonasal transsphenoidal approach using a rigid endoscope. During the nasal and sphenoid phases, iArmS was used to support the surgeon's nondominant arm, which held the endoscope. The details of the iArmS and clinical results were collected. Results iArmS followed the surgeon's arm movement automatically. It reduced the surgeon's fatigue and stabilized the surgeon's hand during ETSS. Shaking of the video image decreased due to the steadying of the surgeon's scope-holding hand with iArmS. There were no complications related to use of the device. Conclusions The intelligent armrest, iArmS, seems to be safe and effective during ETSS. iArmS is helpful for improving the precision and safety not only for microscopic neurosurgery, but also for ETSS. Ongoing advances in robotics ensure the continued evolution of neurosurgery.

Analysis of the detection materials as resonant pads for attaching the measuring arm of the interferometer when sensing mechanical vibrations

NASA Astrophysics Data System (ADS)

Nedoma, Jan; Fajkus, Marcel; Martinek, Radek; Zboril, Ondrej; Bednarek, Lukas; Novak, Martin; Witas, Karel; Vasinek, Vladimir

2017-05-01

Fiber-optic sensors (FOS), today among the most widespread measuring sensors and during various types of measuring, are irreplaceable. Among the distinctive features include immunity to electromagnetic interference, passivity regarding power supply and high sensitivity. One of the representatives FOS is the interferometric sensors working on the principle of interference of light. Authors of this article focused on the analysis of the detection material as resonant pads for attaching the measuring arm of the interferometer when sensing mechanical vibrations (low frequencies). A typical example is the use of interferometer sensors in automobile traffic while sensing a vibration response from the roadway while passing the cars. For analysis was used sensor with Mach-Zehnder interferometer. Defined were different detection materials about different size and thickness. We analyzed the influence on the sensitivity (amplitude response) of the interferometer. Based on the results we have defined the best material for sensing mechanical vibrations. The signal was processed by applications created in LabView development environment. The results were verified by repeated testing in laboratory conditions.

a Review of the Biomechanics and Epidemiology of Working Postures (it Isn't always Vibration which is to BLAME!)

NASA Astrophysics Data System (ADS)

Magnusson, M. L.; Pope, M. H.

1998-08-01

Many vibrational environments also subject the worker to awkward, asymmetric and prolonged postures. This paper reviews the epidemiological, biomechanical and physiological factors involved in working postures which could lead to musculoskeletal problems. Too little or too much sitting leads to low back pain. Sedentary postures, including driving, also lead to a higher risk of a herniated disc. In sitting the pelvis rotates and higher pressures exist in the disk. A backrest inclined to 110° or more and with a lumbar support will reduce the disk pressure. Jobs involving excessive force application will be more apt to cause muscular and ligamentous damage. However, these excessive demands can occur in whole body vibration environments too. Neck, shoulder and arm problems are usually related to posture but can occur in WBV environments. Knee problems, in the standing worker, may be due to a flexed knee posture in an attempt to attenuate vibrations. Excessive postural demands on the neck, shoulder and arm will lead to higher muscle forces and higher joint forces. Recommendations are given to reduce risk of disability.

Sensitivity distribution of a vibration sensor based on Mach-Zehnder interferometer designed inside the window system

NASA Astrophysics Data System (ADS)

Zboril, Ondrej; Nedoma, Jan; Cubik, Jakub; Novak, Martin; Bednarek, Lukas; Fajkus, Marcel; Vasinek, Vladimir

2016-04-01

Interferometric sensors are very accurate and sensitive sensors that due to the extreme sensitivity allow sensing vibration and acoustic signals. This paper describes a new method of implementation of Mach-Zehnder interferometer for sensing of vibrations caused by touching on the window panes. Window panes are part of plastic windows, in which the reference arm of the interferometer is mounted and isolated inside the frame, a measuring arm of the interferometer is fixed to the window pane and it is mounted under the cover of the window frame. It prevents visibility of the optical fiber and this arrangement is the basis for the safety system. For the construction of the vibration sensor standard elements of communication networks are used - optical fiber according to G.652D and 1x2 splitters with dividing ratio 1:1. Interferometer operated at a wavelength of 1550 nm. The paper analyses the sensitivity of the window in a 12x12 measuring points matrix, there is specified sensitivity distribution of the window pane.

Loss of Productivity Due to Neck/Shoulder Symptoms and Hand/Arm Symptoms: Results from the PROMO-Study

PubMed Central

IJmker, Stefan; Blatter, Birgitte M.; de Korte, Elsbeth M.

2007-01-01

Introduction The objective of the present study is to describe the extent of productivity loss among computer workers with neck/shoulder symptoms and hand/arm symptoms, and to examine associations between pain intensity, various physical and psychosocial factors and productivity loss in computer workers with neck/shoulder and hand/arm symptoms. Methods A cross-sectional design was used. The study population consisted of 654 computer workers with neck/shoulder or hand/arm symptoms from five different companies. Descriptive statistics were used to describe the occurrence of self-reported productivity loss. Logistic regression analyses were used to examine the associations. Results In 26% of all the cases reporting symptoms, productivity loss was involved, the most often in cases reporting both symptoms (36%). Productivity loss involved sickness absence in 11% of the arm/hand cases, 32% of the neck/shoulder cases and 43% of the cases reporting both symptoms. The multivariate analyses showed statistically significant odds ratios for pain intensity (OR: 1.26; CI: 1.12–1.41), for high effort/no low reward (OR: 2.26; CI: 1.24–4.12), for high effort/low reward (OR: 1.95; CI: 1.09–3.50), and for low job satisfaction (OR: 3.10; CI: 1.44–6.67). Physical activity in leisure time, full-time work and overcommitment were not associated with productivity loss. Conclusion In most computer workers with neck/shoulder symptoms or hand/arm symptoms productivity loss derives from a decreased performance at work and not from sickness absence. Favorable psychosocial work characteristics might prevent productivity loss in symptomatic workers. PMID:17636455

Vibration sensibility testing in the workplace. Day-to-day reliability.

PubMed

Rosecrance, J C; Cook, T M; Satre, D L; Goode, J D; Schroder, M J

1994-09-01

Loss of vibration sensibility has been suggested as an early indicator of peripheral compression neuropathy, including carpal tunnel syndrome. Although vibration sensibility has been used frequently to evaluate carpal tunnel syndrome, the day-to-day reliability of vibration measurements in an industrial population measured at the workplace has not been assessed. Vibration sensibility testing was performed at the university ergonomics laboratory on 50 volunteers (100 hands) and at a newspaper company on 50 workers (100 hands). Vibration perception and disappearance thresholds were measured on two occasions separated by 3 to 5 days. Student's t tests indicated no significant differences between the first and second tests or between the two groups. Pearson product-moment correlations for test-retest reliability were lower in the industry group but were relatively high despite the less than optimal testing conditions. Our findings suggest that vibration sensibility measurements are reliable from day to day not only in the laboratory but also in the workplace.

Thermoregulatory responses to heat and vibration in men

NASA Technical Reports Server (NTRS)

Spaul, W. A.; Spear, R. C.; Greenleaf, J. E.

1986-01-01

The effect of vibration on thermoregulatory responses was studied in heat-acclimated men exposed suddenly to simultaneous heat and whole body vibrations (WBVs) at two intensity levels, each at graded frequencies between 5 and 80 Hz. The mean rectal temperature (Tre) became elevated more quickly in the WBV exposures than in the controls (heat exposure alone). Both intensity- and frequency-dependent WBV relationships were recorded in localized blood flows and in sweat rates. Thus, vibration appears to reduce the efficiency of the cooling mechanisms during a heat exposure.

Mobile Phone Use Behaviors and Postures on Public Transportation Systems.

PubMed

Liang, Huey-Wen; Hwang, Yaw-Huei

2016-01-01

Mobile phones are common in our daily life, but the users' preferences for postures or screen operating styles have not been studied. This was a cross-sectional and observational study. We randomly sampled passengers who used mobile phones on the Mass Rapid Transit (MRT) system in metropolitan Taipei. A checklist was used to observe their body postures and screen operating styles while sitting or standing. As a result, 1,230 subjects from 400 trips were observed. Overall, of all the passengers who were sitting, 41% of them were using mobile phones. The majority of the tasks involved browsing (84%) with their phones in a portrait orientation (93%). Different-hand holding/operating was the most commonly used operating style while sitting (46%) and same-hand holding/operating was the most common while standing (46%). The distribution of screen operating styles was significantly different for those sitting than for those standing and for different genders and age groups. The most frequently observed postures while sitting were having one's trunk against a backrest, feet on the floor and with or without an arm supported (58%). As for the users who were standing, the both- and different-hands groups had a high proportion of arms unsupported, feet on the floor and either their trunk supported or not. In contrast, the same-hand group tended to have their trunk unsupported, were holding a pole or handstrap and had both feet on floor. Further studies are warranted to characterize the ergonomic exposure of these commonly used postures and operating styles, and our results will help guide the selection of experimental conditions for laboratory settings.

Dynamic dominance varies with handedness: reduced interlimb asymmetries in left-handers

PubMed Central

Przybyla, Andrzej; Good, David C.; Sainburg, Robert L.

2013-01-01

Our previous studies of interlimb asymmetries during reaching movements have given rise to the dynamic-dominance hypothesis of motor lateralization. This hypothesis proposes that dominant arm control has become optimized for efficient intersegmental coordination, which is often associated with straight and smooth hand-paths, while non-dominant arm control has become optimized for controlling steady-state posture, which has been associated with greater final position accuracy when movements are mechanically perturbed, and often during movements made in the absence of visual feedback. The basis for this model of motor lateralization was derived from studies conducted in right-handed subjects. We now ask whether left-handers show similar proficiencies in coordinating reaching movements. We recruited right- and left-handers (20 per group) to perform reaching movements to three targets, in which intersegmental coordination requirements varied systematically. Our results showed that the dominant arm of both left- and right-handers were well coordinated, as reflected by fairly straight hand-paths and low errors in initial direction. Consistent with our previous studies, the non-dominant arm of right-handers showed substantially greater curvature and large errors in initial direction, most notably to targets that elicited higher intersegmental interactions. While the right, non-dominant, hand-paths of left-handers were slightly more curved than those of the dominant arm, they were also substantially more accurate and better coordinated than the non-dominant arm of right-handers. Our results indicate a similar pattern, but reduced lateralization for intersegmental coordination in left-handers. These findings suggest that left-handers develop more coordinated control of their non-dominant arms than right-handers, possibly due to environmental pressure for right-handed manipulations. PMID:22113487

Dynamic dominance varies with handedness: reduced interlimb asymmetries in left-handers.

PubMed

Przybyla, Andrzej; Good, David C; Sainburg, Robert L

2012-02-01

Our previous studies of interlimb asymmetries during reaching movements have given rise to the dynamic-dominance hypothesis of motor lateralization. This hypothesis proposes that dominant arm control has become optimized for efficient intersegmental coordination, which is often associated with straight and smooth hand-paths, while non-dominant arm control has become optimized for controlling steady-state posture, which has been associated with greater final position accuracy when movements are mechanically perturbed, and often during movements made in the absence of visual feedback. The basis for this model of motor lateralization was derived from studies conducted in right-handed subjects. We now ask whether left-handers show similar proficiencies in coordinating reaching movements. We recruited right- and left-handers (20 per group) to perform reaching movements to three targets, in which intersegmental coordination requirements varied systematically. Our results showed that the dominant arm of both left- and right-handers were well coordinated, as reflected by fairly straight hand-paths and low errors in initial direction. Consistent with our previous studies, the non-dominant arm of right-handers showed substantially greater curvature and large errors in initial direction, most notably to targets that elicited higher intersegmental interactions. While the right, non-dominant, hand-paths of left-handers were slightly more curved than those of the dominant arm, they were also substantially more accurate and better coordinated than the non-dominant arm of right-handers. Our results indicate a similar pattern, but reduced lateralization for intersegmental coordination in left-handers. These findings suggest that left-handers develop more coordinated control of their non-dominant arms than right-handers, possibly due to environmental pressure for right-handed manipulations.

Comparison between free-hand and O-arm-based navigated posterior lumbar interbody fusion in elderly cohorts with three-level lumbar degenerative disease.

PubMed

Wang, Yucheng; Chen, Kangwu; Chen, Hao; Zhang, Kai; Lu, Jian; Mao, Haiqing; Yang, Huilin

2018-06-06

This retrospective cohort study aims to evaluate the effects of introducing the O-arm-based navigation technique into the traditional posterior lumbar interbody fusion (PLIF) procedure treating elderly patients with three-level lumbar degenerative diseases. Forty-one consecutive elderly patients were enrolled according to the criteria. There were 21 patients in the free-hand group and 20 patients in the O-arm group. Both two groups underwent the PLIF with or without the O-arm-based navigation technique. The demographic features, clinical data and outcomes, and radiological information were collected for further analysis. The average follow-up time was 18.3 (range, 12-28) months in the free-hand group and 16.7 (range, 12-24) months in the O-arm group. Comparison between two groups revealed no significant difference regarding demographic features. The operation time took in the navigation group was significantly less than that in the free-hand group (222.55 ± 38.00 mins versus 255.19 ± 40.26 mins, P < 0.05). Both VAS and ODI were improved post-operatively in two groups while comparison between groups showed no difference. The accuracy rate of pedicle screw positioning was 88.7% in the free-hand group to 96.9% in the O-arm group (P < 0.05). The O-arm-based navigation is an efficacious auxiliary technique which could significantly improve the accuracy of pedicle screw insertion, especially in cases of patients with complex anatomic degenerative diseases, without sacrificing the feasibility and reliable outcome of traditional PLIF.

Modulation of Arm Reaching Movements during Processing of Arm/Hand-Related Action Verbs with and without Emotional Connotation

PubMed Central

Spadacenta, Silvia; Gallese, Vittorio; Fragola, Michele; Mirabella, Giovanni

2014-01-01

The theory of embodied language states that language comprehension relies on an internal reenactment of the sensorimotor experience associated with the processed word or sentence. Most evidence in support of this hypothesis had been collected using linguistic material without any emotional connotation. For instance, it had been shown that processing of arm-related verbs, but not of those leg-related verbs, affects the planning and execution of reaching movements; however, at present it is unknown whether this effect is further modulated by verbs evoking an emotional experience. Showing such a modulation might shed light on a very debated issue, i.e. the way in which the emotional meaning of a word is processed. To this end, we assessed whether processing arm/hand-related verbs describing actions with negative connotations (e.g. to stab) affects reaching movements differently from arm/hand-related verbs describing actions with neutral connotation (e.g. to comb). We exploited a go/no-go paradigm in which healthy participants were required to perform arm-reaching movements toward a target when verbs expressing emotional hand actions, neutral hand actions or foot actions were shown, and to refrain from moving when no-effector-related verbs were presented. Reaction times and percentages of errors increased when the verb involved the same effector as used to give the response. However, we also found that the size of this interference decreased when the arm/hand-related verbs had a negative emotional connotation. Crucially, we show that such modulation only occurred when the verb semantics had to be retrieved. These results suggest that the comprehension of negatively valenced verbs might require the simultaneous reenactment of the neural circuitry associated with the processing of the emotion evoked by their meaning and of the neural circuitry associated with their motor features. PMID:25093410

Arm to leg coordination in elite butterfly swimmers.

PubMed

Chollet, D; Seifert, L; Boulesteix, L; Carter, M

2006-04-01

This study proposed the use of four time gaps to assess arm-to-leg coordination in the butterfly stroke at increasing race paces. Fourteen elite male swimmers swam at four velocities corresponding to the appropriate paces for, respectively, the 400-m, 200-m, 100-m, and 50-m events. The different stroke phases of the arm and leg were identified by video analysis and then used to calculate four time gaps (T1: time gap between entry of the hands in the water and the high break-even point of the first undulation; T2: time gap between the beginning of the hands' backward movement and the low break-even point of the first undulation; T3: time gap between the hands' arrival in a vertical plane to the shoulders and the high break-even point of the second undulation; T4: time gap between the hands' release from the water and the low break-even point of the second undulation), the values of which described the changing relationship of arm to leg movements over an entire stroke cycle. With increases in pace, elite swimmers increased the stroke rate, the relative duration of the arm pull, the recovery and the first downward movement of the legs, and decreased the stroke length, the relative duration of the arm catch phase and the body glide with arms forward (measured by T2), until continuity in the propulsive actions was achieved. Whatever the paces, the T1, T3, and T4 values were close to zero and revealed a high degree of synchronisation at key motor points of the arm and leg actions. This new method to assess butterfly coordination could facilitate learning and coaching by situating the place of the leg undulation in relation with the arm stroke.

Role of contralesional hemisphere in paretic arm reaching in patients with severe arm paresis due to stroke: A preliminary report.

PubMed

Mohapatra, Sambit; Harrington, Rachael; Chan, Evan; Dromerick, Alexander W; Breceda, Erika Y; Harris-Love, Michelle

2016-03-23

Stroke is highly prevalent and a leading cause of serious, long-term disability among American adults. Impaired movement (i.e. paresis) of the stroke-affected arm is a major contributor to post-stroke disability, yet the mechanisms of upper extremity motor recovery are poorly understood, particularly in severely impaired patients who lack hand function. To address this problem, we examined the functional relevance of the contralesional hemisphere in paretic arm motor performance in individuals with severe arm paresis. Twelve individuals with severe stroke-induced arm paresis (Upper Extremity Fugl-Meyer Assessment=17.1 ± 8.5; maximum score=66) participated in the study. Participants performed a reaching response time task with their paretic arm. At varying time intervals following a 'Go' cue, a pair of transcranial magnetic stimulation (TMS) pulses were delivered to contralesional hemisphere primary motor (M1) or dorsal pre-motor cortex (PMd) to momentarily disrupt the pattern of neural firing. Response time components and hand-path characteristics were compared across the 2 sites for trials with and without TMS disruption. There was no significant effect of TMS disruption on overall Response time or Reaction time, but Movement time was significantly longer (i.e. slower) with disruption of the contralesional hemisphere (p=0.015), regardless of which area was stimulated. Peak hand-path velocity and hand-path smoothness were also significantly lower (p=0.005 and p<0.0001, respectively) with TMS disruption of the contralesional hemisphere. The data from this study provide evidence supporting a functionally relevant role of contralesional hemisphere motor areas in paretic arm reaching movements in individuals with severe post-stroke arm impairment. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Influence of support conditions on vertical whole-body vibration of the seated human body.

PubMed

M-Pranesh, Anand; Rakheja, Subhash; Demont, Richard

2010-01-01

The vibration transmission to the lumbar and thoracic segments of seated human subjects exposed to whole body vibration of a vehicular nature have been mostly characterised without the back and hand supports, which is not representative of general driving conditions. This non-invasive experimental study investigated the transmission of vertical seat vibration to selected vertebrae and the head along the vertical and fore-aft axes of twelve male human subjects seated on a rigid seat and exposed to random vertical excitation in the 0.5-20 Hz range. The measurements were performed under four different sitting postures involving combinations of back support conditions and hands positions, and three difference magnitudes of vertical vibration (0.25, 0.5 and 1.0 m/s(2) rms acceleration). The results showed significant errors induced by sensor misalignment and skin effects, which required appropriate correction methodologies. The averaged corrected responses revealed that the back support attenuates vibration in the vertical axis to all the body locations while increasing the fore-aft transmissibility at the C7 and T5. The hands position generally has a relatively smaller effect, showing some influences on the C7 and L5 vibration. Sitting without a back support resulted in very low magnitude fore-aft vibration at T5, which was substantially higher with a back support, suggestive of a probable change in the body's vibration mode. The effect of back support was observed to be very small on the horizontal vibration of the lower thoracic and lumbar regions. The results suggest that distinctly different target body-segment biodynamic functions need to be defined for different support conditions in order to represent the unique contribution of the specific support condition. These datasets may then be useful for the development of biodynamic models.

Hand grip strength and anthropometric characteristics in Italian female national basketball teams.

PubMed

Pizzigalli, Luisa; Micheletti Cremasco, Margherita; LA Torre, Antonio; Rainoldi, Alberto; Benis, Roberto

2017-05-01

The aim of this study was to investigate the influence of hand and body dimensions on hand grip strength and to define a reference scale for talent identification in basketball players. Body and hand anthropometric data and the maximal handgrip strength of 109 female Italian basketball National players (Under14-Seniores) were measured. Handgrip strength and arm length trend increased, raising the statistical significant differences only for players from the age of 19 (U20, Seniores) with respect to sub-elite groups (U14, U15) (P<0.05). Handgrip strength showed low positive correlations with height and Body Mass Index but a positive relationships with arm length (r=0.5; P<0.001). Findings underline training and years of practice have effects on increasing handgrip strength. Data show that to select female basketball players by arm length means selecting by handgrip strength. Thus it is possible to suggest that in addition to height, arm length could also be considered a useful parameter in young female talent identification.

[Arm Motor Function Recovery during Rehabilitation with the Use of Hand Exoskeleton Controlled by Brain-Computer Interface: a Patient with Severe Brain Damage].

PubMed

Biryukova, E V; Pavlova, O G; Kurganskaya, M E; Bobrov, P D; Turbina, L G; Frolov, A A; Davydov, V I; Sil'tchenko, A V; Mokienko, O A

2016-01-01

We studied the dynamics of motor function recovery in a patient with severe brain damage in the course of neurorehabilitation using hand exoskeleton controlled by brain-computer interface. For estimating the motor function of paretic arm, we used the biomechanical analysis of movements registered during the course of rehabilitation. After 15 weekly sessions of hand exoskeleton control, the following results were obtained: a) the velocity profile of goal-directed movements of paretic hand became bell-shaped, b) the patient began to extend and abduct the hand which was flexed and adducted in the beginning of rehabilitation, and c) the patient began to supinate the forearm which was pronated in the beginning of rehabilitation. The first result is an evidence of the general improvement of the quality of motor control, while the second and third results prove that the spasticity of paretic arm has decreased.

Effect of hand-arm exercise on venous blood constituents during leg exercise

NASA Technical Reports Server (NTRS)

Wong, N.; Silver, J. E.; Greenawalt, S.; Kravik, S. E.; Geelen, G.

1985-01-01

Contributions by ancillary hand and arm actions to the changes in blood constituents effected by leg exercises on cycle ergometer were assessed. Static or dynamic hand-arm exercises were added to the leg exercise (50 percent VO2 peak)-only control regimens for the subjects (19-27 yr old men) in the two experimental groups. Antecubital venous blood was analyzed at times 0, 15, and 30 min (T0, T15, and T30) for serum Na(+), K(+), osmolality, albumin, total CA(2+), and glucose; blood hemoglobin, hematocrit, and lactic acid; and change in plasma volume. Only glucose and lactate values were affected by additional arm exercise. Glucose decreased 4 percent at T15 and T30 after static exercise, and by 2 percent at T15 (with no change at T30) after dynamic arm exercise. Conversely, lactic acid increased by 20 percent at T30 after static exercise, and by 14 percent by T15 and 6 percent at T30 after dynamic arm exercise. It is concluded that additional arm movements, performed usually when gripping the handle-bar on the cycle ergometer, could introduce significant errors in measured venous concentrations of glucose and lactate in the leg-exercised subjects.

Fingers' vibration transmission and grip strength preservation performance of vibration reducing gloves.

PubMed

Hamouda, K; Rakheja, S; Dewangan, K N; Marcotte, P

2018-01-01

The vibration isolation performances of vibration reducing (VR) gloves are invariably assessed in terms of power tools' handle vibration transmission to the palm of the hand using the method described in ISO 10819 (2013), while the nature of vibration transmitted to the fingers is ignored. Moreover, the VR gloves with relatively low stiffness viscoelastic materials affect the grip strength in an adverse manner. This study is aimed at performance assessments of 12 different VR gloves on the basis of handle vibration transmission to the palm and the fingers of the gloved hand, together with reduction in the grip strength. The gloves included 3 different air bladder, 3 gel, 3 hybrid, and 2 gel-foam gloves in addition to a leather glove. Two Velcro finger adapters, each instrumented with a three-axis accelerometer, were used to measure vibration responses of the index and middle fingers near the mid-phalanges. Vibration transmitted to the palm was measured using the standardized palm adapter. The vibration transmissibility responses of the VR gloves were measured in the laboratory using the instrumented cylindrical handle, also described in the standard, mounted on a vibration exciter. A total of 12 healthy male subjects participated in the study. The instrumented handle was also used to measure grip strength of the subjects with and without the VR gloves. The results of the study showed that the VR gloves, with only a few exceptions, attenuate handle vibration transmitted to the fingers only in the 10-200 Hz and amplify middle finger vibration at frequencies exceeding 200 Hz. Many of the gloves, however, provided considerable reduction in vibration transmitted to the palm, especially at higher frequencies. These suggest that the characteristics of vibration transmitted to fingers differ considerably from those at the palm. Four of the test gloves satisfied the screening criteria of the ISO 10819 (2013) based on the palm vibration alone, even though these caused amplification of handle vibration at the fingers. The fingers' vibration transmission performance of gloves were further evaluated using a proposed finger frequency-weighting W f apart from the standardized W h -weighting. It is shown that the W h weighting generally overestimates the VR glove effectiveness in limiting the fingers vibration in the high (H: 200-1250 Hz) frequency range. Both the weightings, however, revealed comparable performance of gloves in the mid (M: 25-200 Hz) frequency range. The VR gloves, with the exception of the leather glove, showed considerable reductions in the grip strength (27-41%), while the grip strength reduction was not correlated with the glove material thickness. It is suggested that effectiveness of VR gloves should be assessed considering the vibration transmission to both the palm and fingers of the hand together with the hand grip strength reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Changes in thermal and mechanical pain thresholds in hand amputees. A clinical and physiological long-term follow-up.

PubMed

Wahren, L K

1990-09-01

In a previous study, allodynia to cold and vibratory stimuli was found in the finger stumps of 24 patients with amputations, control values being obtained from fingers of the intact contralateral hand. When treated with regional intravenous guanethidine block (RGB), some of the patients only had short-lasting relief of symptoms, whereas others experienced a more long-lasting beneficial effect. In the present long-term follow-up study the patients were re-examined 6 years after the RGB treatment. The aim was to investigate whether the earlier symptoms and signs persisted, and whether there were any differences in these respects, between patients with long-lasting (group 1) and short-lasting relief of symptoms after RGB (group 2). All 24 patients were asked to answer a questionnaire concerning their clinical symptoms. In addition, 14 of them visited the laboratory for determination of thermal and vibration-induced pain thresholds. Comparisons were made with values obtained at the first examination before RGB treatment and with values from 14 healthy subjects tested in a similar way on 2 occasions with an interval of 8 years. Twenty of 23 patients reported that cold exposure still evoked stump pain. However, the threshold measurements showed that with time the patients had become more tolerant to thermal stimuli not only in the injured but also in the uninjured hand. A rise in pain threshold was also observed when vibration-induced pain was tested in the injured hand. There was no significant difference between groups 1 and 2. Similar changes in pain thresholds with time were not observed in the group of healthy control subjects.

Translational control of a graphically simulated robot arm by kinematic rate equations that overcome elbow joint singularity

NASA Technical Reports Server (NTRS)

Barker, L. K.; Houck, J. A.; Carzoo, S. W.

1984-01-01

An operator commands a robot hand to move in a certain direction relative to its own axis system by specifying a velocity in that direction. This velocity command is then resolved into individual joint rotational velocities in the robot arm to effect the motion. However, the usual resolved-rate equations become singular when the robot arm is straightened. To overcome this elbow joint singularity, equations were developed which allow continued translational control of the robot hand even though the robot arm is (or is nearly) fully extended. A feature of the equations near full arm extension is that an operator simply extends and retracts the robot arm to reverse the direction of the elbow bend (difficult maneuver for the usual resolved-rate equations). Results show successful movement of a graphically simulated robot arm.

Cochlear Damages Caused by Vibration Exposure

PubMed Central

Moussavi Najarkola, Seyyed Ali; Khavanin, Ali; Mirzaei, Ramazan; Salehnia, Mojdeh; Muhammadnejad, Ahad

2013-01-01

Background Many industrial devices have an excessive vibration which can affect human body systems. The effect of vibration on cochlear histology has been as a debatable problem in occupational health and medicine. Objectives Due to limitation present in human studies, the research was conducted to survey the influence of vibration on cochlear histology in an animal model. Materials and Methods Twelve albino rabbits were experimented as: Vibration group (n = 6; exposed to 1.0 m.s-2 r.m.s vertical whole-body vibration at 4 - 8 Hz for 8 hours per day during 5 consecutive days) versus Control group (n = 6; the same rabbits without vibration exposure). After finishing the exposure scenario, all rabbits were killed by CO2 inhalation; their cochleae were extracted and fixed in 10% formaldehyde for 48 hours, decalcified by 10% nitric acid for 24 hours. Specimens were dehydrated, embedded, sectioned 5 µm thick and stained with Hematoxylin and Eosin for light microscopy observations. Results Severely hydropic degenerated and vacuolated inner hair cells (IHCs) were observed in vibration group compared to the control group. Inter and intracellular edema was appeared in supporting cells (SC). Nuclei of outer hair cells (OHCs) seemed to be pyknotic. Slightly thickened basilar membrane (BM) was probably implied to inter cellular edematous. Tectorial Membrane (TM) was not affected pathologically. Conclusions Whole-body vibration could cause cochlear damages in male rabbits, though vibration-induced auditory functional effects might be resulted as subsequent outcome of prolonged high level vibration exposures. PMID:24616783

Vibration exercise makes your muscles and bones stronger: fact or fiction?

PubMed

Cardinale, Marco; Rittweger, Jörn

2006-03-01

Vibration transmitted to the whole body or part of it has been extensively studied in relation to the risks to the health and safety of workers. These studies have highlighted the particular danger of lower-back morbidity and spinal trauma arising after prolonged exposure to vibration. However, short-term exposure to whole-body vibration (WBV) or the use of vibrating dumbbells can have beneficial effects on the musculoskeletal system. As a consequence of this encouraging work, many manufacturers have developed exercise devices characterized by vibrating plates transmitting vibration to the whole body and vibrating dumbbells. Preliminary results seem to recommend WBV exercise as a therapeutic alternative for preventing/reversing sarcopenia and possibly osteoporosis. However, there is a paucity of well designed studies in the elderly. In particular, there is a lack of understanding of the physiological mechanisms involved in the adaptive responses to vibration exposure, and of the most appropriate vibration parameters to be used in order to maximize gains and improve safety. The effectiveness of this novel exercise modality on musculoskeletal structures is examined in this review. The physiological mechanisms involved in the adaptive responses to vibration exercise are discussed and suggestions for future studies are made.

Assessment of whole-body vibration exposures and influencing factors for quarry haul truck drivers and loader operators

PubMed Central

Mayton, Alan G.; Jobes, Christopher C.; Gallagher, Sean

2015-01-01

To further assess vibration exposure on haul trucks (HTs) and front-end wheel loaders (FELs), follow-up investigations were conducted at two US crushed stone operations. The purpose was to: 1) evaluate factors such as load/no-load conditions, speed, load capacity, vehicle age, and seat transmissibility relative to vibration exposure; 2) compare exposure levels with existing ISO/ANSI and EUGPG guidelines. Increasing HT speed increased recorded vibration at the chassis and seat as expected. Neither vehicle load nor vehicle speed increased transmissibility. Increasing HT size and age did show transmissibility decreasing. HT dominant-axis wRMS levels (most often the y-axis, lateral or side-to-side direction) were predominantly within the health guidance caution zone (HGCZ). However, several instances showed vibration dose value (VDV) above the exposure limit value (ELV) for the ISO/ANSI guidelines. VDV levels (all dominant x-axis or fore-aft) were within and above the HGCZ for the EUGPG and above the HGCZ for ISO/ANSI guidelines. PMID:26361493

Upper limb joint kinetics of three sitting pivot wheelchair transfer techniques in individuals with spinal cord injury.

PubMed

Kankipati, Padmaja; Boninger, Michael L; Gagnon, Dany; Cooper, Rory A; Koontz, Alicia M

2015-07-01

Repeated measures design. This study compared the upper extremity (UE) joint kinetics between three transfer techniques. Research laboratory. Twenty individuals with spinal cord injury performed three transfer techniques from their wheelchair to a level tub bench. Two of the techniques involved a head-hips method with leading hand position close (HH-I) and far (HH-A) from the body, and the third technique with the trunk upright (TU) and hand far from body. Motion analysis equipment recorded upper body movements and force sensors recorded their hand and feet reaction forces during the transfers. Several significant differences were found between HH-A and HH-I and TU and HH-I transfers indicating that hand placement was a key factor influencing the UE joint kinetics. Peak resultant hand, elbow, and shoulder joint forces were significantly higher for the HH-A and TU techniques at the trailing arm (P < 0.036) and lower at the leading arm (P < 0.021), compared to the HH-I technique. Always trailing with the same arm if using HH-A or TU could predispose that arm to overuse related pain and injuries. Technique training should focus on initial hand placement close to the body followed by the amount of trunk flexion needed to facilitate movement.

Effect of vibration duration on human discomfort. [passenger comfort and random vibration

NASA Technical Reports Server (NTRS)

Clevenson, S. A.; Dempsey, T. K.; Leatherwood, J. D.

1978-01-01

The duration effects of random vertical vibration on passenger discomfort were studied in a simulated section of an aircraft cabin configured to seat six persons in tourist-class style. Variables of the study included time of exposure (0.25 min to 60 min) and the rms amplitude of vibration (0.025g to 0.100g). The vibrations had a white noise spectrum with a bandwidth of 10 Hz centered at 5 Hz. Data indicate that the discomfort threshold occurred at an rms vertical acceleration level of 0.027g for all durations of vibration. However, for acceleration levels that exceeded the discomfort threshold, a systematic decrease in discomfort occurred as a function of increasing duration of vibration. For the range of accelerations used, the magnitude of the discomfort decrement was shown to be independent of acceleration level. The results suggest that discomfort from vertical vibration applied in the frequency range at which humans are most sensitive decreases with longer exposure, which is the opposite of the recommendation of the International Standard ISO 2631-1974 (E) Guide for the Evaluation of Human Exposure to Whole-Body Vibration.

Human-Human Interaction Forces and Interlimb Coordination During Side-by-Side Walking With Hand Contact.

PubMed

Sylos-Labini, Francesca; d'Avella, Andrea; Lacquaniti, Francesco; Ivanenko, Yury

2018-01-01

Handholding can naturally occur between two walkers. When people walk side-by-side, either with or without hand contact, they often synchronize their steps. However, despite the importance of haptic interaction in general and the natural use of hand contact between humans during walking, few studies have investigated forces arising from physical interactions. Eight pairs of adult subjects participated in this study. They walked on side-by-side treadmills at 4 km/h independently and with hand contact. Only hand contact-related sensory information was available for unintentional synchronization, while visual and auditory communication was obstructed. Subjects walked at their natural cadences or following a metronome. Limb kinematics, hand contact 3D interaction forces and EMG activity of 12 upper limb muscles were recorded. Overall, unintentional step frequency locking was observed during about 40% of time in 88% of pairs walking with hand contact. On average, the amplitude of contact arm oscillations decreased while the contralateral (free) arm oscillated in the same way as during normal walking. Interestingly, EMG activity of the shoulder muscles of the contact arm did not decrease, and their synergistic pattern remained similar. The amplitude of interaction forces and of trunk oscillations was similar for synchronized and non-synchronized steps, though the synchronized steps were characterized by significantly more regular orientations of interaction forces. Our results further support the notion that gait synchronization during natural walking is common, and that it may occur through interaction forces. Conservation of the proximal muscle activity of the contact (not oscillating) arm is consistent with neural coupling between cervical and lumbosacral pattern generation circuitries ("quadrupedal" arm-leg coordination) during human gait. Overall, the findings suggest that individuals might integrate force interaction cues to communicate and coordinate steps during walking.

Human-Human Interaction Forces and Interlimb Coordination During Side-by-Side Walking With Hand Contact

PubMed Central

Sylos-Labini, Francesca; d'Avella, Andrea; Lacquaniti, Francesco; Ivanenko, Yury

2018-01-01

Handholding can naturally occur between two walkers. When people walk side-by-side, either with or without hand contact, they often synchronize their steps. However, despite the importance of haptic interaction in general and the natural use of hand contact between humans during walking, few studies have investigated forces arising from physical interactions. Eight pairs of adult subjects participated in this study. They walked on side-by-side treadmills at 4 km/h independently and with hand contact. Only hand contact-related sensory information was available for unintentional synchronization, while visual and auditory communication was obstructed. Subjects walked at their natural cadences or following a metronome. Limb kinematics, hand contact 3D interaction forces and EMG activity of 12 upper limb muscles were recorded. Overall, unintentional step frequency locking was observed during about 40% of time in 88% of pairs walking with hand contact. On average, the amplitude of contact arm oscillations decreased while the contralateral (free) arm oscillated in the same way as during normal walking. Interestingly, EMG activity of the shoulder muscles of the contact arm did not decrease, and their synergistic pattern remained similar. The amplitude of interaction forces and of trunk oscillations was similar for synchronized and non-synchronized steps, though the synchronized steps were characterized by significantly more regular orientations of interaction forces. Our results further support the notion that gait synchronization during natural walking is common, and that it may occur through interaction forces. Conservation of the proximal muscle activity of the contact (not oscillating) arm is consistent with neural coupling between cervical and lumbosacral pattern generation circuitries (“quadrupedal” arm-leg coordination) during human gait. Overall, the findings suggest that individuals might integrate force interaction cues to communicate and coordinate steps during walking. PMID:29563883

Control strategies for a telerobot

NASA Technical Reports Server (NTRS)

Ohara, John; Stasi, Bill

1989-01-01

One of the major issues impacting the utility of telerobotic systems for space is the development of effective control strategies. For near-term applications, telerobot control is likely to utilize teleoperation methodologies with integrated supervisory control capabilities to assist the operator. Two different approaches to telerobotic control are evaluated: bilateral force reflecting master controllers and proportional rate six degrees-of-freedom hand controllers. The controllers' performance of single manipulator arm tasks is compared. Simultaneous operation of both manipulator arms and complex multiaxis slave arm movements is investigated. Task times are significantly longer and fewer errors are committed with the hand controllers. The hand controllers are also rated significantly higher in cognitive and manual control workload on the two-arm task. The master controllers are rated significantly higher in physical workload. The implications of these findings for space teleoperations and higher levels of control are discussed.

ELECTRIC CONTACT MEANS

DOEpatents

Grear, J.W. Jr.

1959-03-10

A switch adapted to maintain electrical connections under conditions of vibration or acceleration is described. According to the invention, thc switch includes a rotatable arm carrying a conductive bar arranged to close against two contacts spaced in the same plane. The firm and continuous engagement of the conductive bar with the contacts is acheived by utilizeing a spring located betwenn the vbar and athe a rem frzme and slidable mounting the bar in channel between two arms suspendef from the arm frame.

Nonlinear adaptive control of an elastic robotic arm

NASA Technical Reports Server (NTRS)

Singh, S. N.

1986-01-01

An approach to control of a class of nonlinear flexible robotic systems is presented. For simplicity, a robot arm (PUMA-type) with three rotational joints is considered. The third link is assumed to be elastic. An adaptive torquer control law is derived for controlling the joint angles. This controller includes a dynamic system in the feedback path, requires only joint angle and rate for feedback, and asymptotically decomposes the elastic dynamics into two subsystems representing the transverse vibrations of the elastic link in two orthogonal planes. To damp out the elastic vibration, a force control law using modal feedback is synthesized. The combination of the torque and force control laws accomplishes joint angle control and elastic mode stabilization.

The Reliability and Factor Structure of the Job Activity Preference Questionnaire (JAPQ) and the Job Behavior Experience Questionnaire (JBEQ)

DTIC Science & Technology

1982-01-01

different bits of information to fly his plane, etc.) 35. Analyzing information (interpreting financial reports, determining why an automobile engine...involvin- hand and arm movements, as might be used in repairing automobiles , packaging products, etc.) I48. liand-arm steadiness (steady hand and arm...devices (pianos, typewriters, adding Rating Scale machines, etc.) 0 None 100. Highway or rail vehicles ( automobiles , trucks, 1 Very limited buses, trains

Nonlinear effects contributing to hand-stopping tones in a horn.

PubMed

Ebihara, Takayasu; Yoshikawa, Shigeru

2013-05-01

Hand stopping is a technique for playing the French horn while closing the bell relatively tightly using the right hand. The resulting timbre is called "penetrating" and "metallic." The effect of hand stopping on the horn input impedance has been studied, but the tone quality has hardly ever been considered. In the present paper, the dominant physical cause of the stopped-tone quality is discussed in detail. Numerical calculations of the transmission function of the stopped-horn model and the measurements of both sound pressure and wall vibration in hand stopping are carried out. They strongly suggest that the metallicness of the stopped tone is characterized by the generation of higher harmonics extending over 10 kHz due to the rapidly corrugating waveform and that the associated wall vibration on the bell may be responsible for this higher harmonic generation. However, excitation experiments and immobilization experiments performed to elucidate the relationship between sound radiation and wall vibration deny their correlation. Instead, the measurement result of the mouthpiece pressure in hand stopping suggests that minute wave corrugations peculiar to the metallic stopped tones are probably formed by nonlinear sound propagation along the bore.

Dynamics, control and sensor issues pertinent to robotic hands for the EVA retriever system

NASA Technical Reports Server (NTRS)

Mclauchlan, Robert A.

1987-01-01

Basic dynamics, sensor, control, and related artificial intelligence issues pertinent to smart robotic hands for the Extra Vehicular Activity (EVA) Retriever system are summarized and discussed. These smart hands are to be used as end effectors on arms attached to manned maneuvering units (MMU). The Retriever robotic systems comprised of MMU, arm and smart hands, are being developed to aid crewmen in the performance of routine EVA tasks including tool and object retrieval. The ultimate goal is to enhance the effectiveness of EVA crewmen.

The effects of vibratory stimulation employed to forearm and arm flexor muscles on upper limb function in patients with chronic stroke.

PubMed

Jung, Sang-Mi

2017-09-01

[Purpose] The purpose of this study was to investigate not only the effects of stimulatory vibration but also the retained effects 2 weeks after the last session of the intervention. [Subjects and Methods] Ten subjects with post-stroke hemiplegia were recruited in this study. The experimental group (EG) received vibratory stimulation for 30 minutes in each session, three times a week for 2 weeks. Grip strength (GS), box-and-block test (BBT), and Weinstein monofilament were used to assess hand strength, dexterity, and sensory in the affected hand, respectively. [Results] A significant difference was found between the pre- and post-follow-up BBT. Significant differences were found among the pre-posttest, post-follow-up test, and pre-follow-up test results for GS and BBT. [Conclusion] This study was conducted with 10 subjects, without a control group, to verify the pure effect of the intervention. As a result, significant positive effects were observed in the post-test and follow-up test of GS and BBT. Therefore, repeated vibratory stimulation influenced GS and BBT after the 2-week intervention and retained the effect for 2 more weeks.

Combined exposures of whole-body vibration and awkward posture: a cross sectional investigation among occupational drivers by means of simultaneous field measurements.

PubMed

Raffler, Nastaran; Rissler, Jörg; Ellegast, Rolf; Schikowsky, Christian; Kraus, Thomas; Ochsmann, Elke

2017-11-01

Multifactorial workloads such as whole-body vibration (WBV), awkward posture and heavy lifting are potential predictors for low back pain (LBP). In this study, we investigate the association between LBP and these exposures among 102 professional drivers. The combined exposures of WBV and posture are measured at different workplaces. Health and personal data as well as information about lifting tasks are collected by a questionnaire. The daily vibration exposure value (odds ratio 1.69) and an index for awkward posture (odds ratio 1.63) show significant association with the occurence of LBP. Awkward posture and heavy lifting appear to be more strongly associated with sick leave than WBV exposure. Furthermore, a combination of the measurement results of WBV and awkward posture into one quantity also shows significant correlation to LBP. The combined exposure of WBV and awkward posture can be described in terms of the daily vibration exposure and the index for awkward posture. This facilitates work place assessments and future research in this area. Practitioner Summary: For the first time, quantitative measures combining whole-body vibration and awkward posture exposures have shown to correlate with the occurrence of low back pain significantly. This validates the proposed quantities and measurement methods, which facilitate workplace assessments and assist in the design of further studies which are necessary to establish a causal exposure-response relationship.

The influence of computer-generated path on the robot’s effector stability of motion

NASA Astrophysics Data System (ADS)

Foit, K.; Banaś, W.; Gwiazda, A.; Ćwikła, G.

2017-08-01

The off-line trajectory planning is often carried out due to economical and practical reasons: the robot is not excluded from the production process and the operator could benefit from testing programs in the virtual environment. On the other hand, the dedicated off-line programming and simulation software is often limited in features and is intended to roughly check the program. It should be expected that the arm of the real robot’s manipulator will realize the trajectory in different manner: the acceleration and deceleration phases may trigger the vibrations of the kinematic chain that could affect the precision of effector positioning and degrade the quality of process realized by the robot. The purpose of this work is the analysis of the selected cases, when the robot’s effector has been moved along the programmed path. The off-line generated, test trajectories have different arrangement of points: such approach has allowed evaluating the time needed to complete the each of the tasks, as well as measuring the level of the vibration of the robot’s wrist. All tests were performed without the load. The conclusions of the experiment may be useful during the trajectory planning in order to avoid the critical configuration of points.

Evaluation of commercially available seat suspensions to reduce whole body vibration exposures in mining heavy equipment vehicle operators.

PubMed

Kim, Jeong Ho; Marin, Luz S; Dennerlein, Jack T

2018-09-01

As mining vehicle operators are exposed to high level of Whole body vibration (WBV) for prolonged periods of time, approaches to reduce this exposure are needed for the specific types of exposures in mining. Although various engineering controls (i.e. seat suspension systems) have been developed to address WBV, there has been lack of research to systematically evaluate these systems in reducing WBV exposures in mining heavy equipment vehicle settings. Therefore, this laboratory-based study evaluated the efficacy of different combinations of fore-aft (x-axis), lateral (y-axis), and vertical (z-axis) suspensions in reducing WBV exposures. The results showed that the active vertical suspension more effectively reduced the vertical vibration (∼50%; p's < 0.0001) as compared to the passive vertical suspension (10%; p's < 0.11). The passive fore-aft (x-axis) and lateral (y-axis) suspension systems did not attenuate the corresponding axis vibration (p's > 0.06) and sometimes amplified the floor vibration, especially when the non-vertical vibration was predominant (p's < 0.02). These results indicate that there is a critical need to develop more effective engineering controls including better seat suspensions to address non-vertical WBV exposures, especially because these non-vertical WBV exposures can increase risks for adverse health effects including musculoskeletal loading, discomfort, and impaired visual acuity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Hand Gesture Based Wireless Robotic Arm Control for Agricultural Applications

NASA Astrophysics Data System (ADS)

Kannan Megalingam, Rajesh; Bandhyopadhyay, Shiva; Vamsy Vivek, Gedela; Juned Rahi, Muhammad

2017-08-01

One of the major challenges in agriculture is harvesting. It is very hard and sometimes even unsafe for workers to go to each plant and pluck fruits. Robotic systems are increasingly combined with new technologies to automate or semi automate labour intensive work, such as e.g. grape harvesting. In this work we propose a semi-automatic method for aid in harvesting fruits and hence increase productivity per man hour. A robotic arm fixed to a rover roams in the in orchard and the user can control it remotely using the hand glove fixed with various sensors. These sensors can position the robotic arm remotely to harvest the fruits. In this paper we discuss the design of hand glove fixed with various sensors, design of 4 DoF robotic arm and the wireless control interface. In addition the setup of the system and the testing and evaluation under lab conditions are also presented in this paper.

[The Activation of Interlimb Interactions Increase the Motor Output in Legs in Healthy Subjects under the Conditions of Arm and Leg Unloading].

PubMed

Selionov, V A; Solopova, I A; Zhvansky, D S

2016-01-01

We studied the effect of arm movements and movements of separate arm joints on the electrophysiological and kinematic characteristics of voluntary and vibration-triggered stepping-like leg movements under the conditions of horizontal support of upper and lower limbs. The horizontal support of arms provided a significantly increase in the rate of activation of locomotor automatism by non-invasive impact on tonic sensory inputs. The addition of active arm movements during involuntary rhytmic stepping-like leg movements led to an increase in EMG activity of hip muscles and was accompanied by an increase in the amplitude of hip and shin movements. Passive arm movements had the same effect on induced leg movements. The movement of the shoulder joints led to an increase in the activity of hip muscles and an increase in the amplitude of movements of the knee and hip joints. At the same time, the movement of forearms. and wrists had similar facilitating effect on electrophysiological and kinematic characteristics of rhytmic stepping-like movements, but influenced the distal segments of legs to a greater extent. Under the conditions of sub-threshold vibration of leg muscles, voluntary arm movements led to the activation of involuntary rhytmic stepping movements. During voluntary leg movements, the addition of arm movements had a significantly smaller impact on the parameters of rhytmic stepping than during involuntary leg movements. Thus, the simultaneous movements of upper and lower limbs are an effective method of activation of neural networks connecting the rhythm generators of arms and legs. Under the conditions of arm and leg unloading, the interactions between the cervical and lumbosacral segments of the spinal cord seem to play the major role in the impact of arm movements on the patterns of leg movements. The described methods of activation of interlimb interactions can be used in the rehabilitation of post-stroke patients and patients with spinal cord injuries, Parkinson's disease and other neurological diseases.

Low back and neck pain in locomotive engineers exposed to whole-body vibration.

PubMed

McBride, David; Paulin, Sara; Herbison, G Peter; Waite, David; Bagheri, Nasser

2014-01-01

The objective of this study was to determine the prevalence and excess risk of low back pain and neck pain in locomotive engineers, and to investigate the relationship of both with whole-body vibration exposure. A cross-sectional survey comparing locomotive engineers with other rail worker referents was conducted. Current vibration levels were measured, cumulative exposures calculated for engineers and referents, and low back and neck pain assessed by a self-completed questionnaire. Median vibration exposure in the z- (vertical) axis was 0.62 m/s(2). Engineers experienced more frequent low back and neck pain, odds ratios (ORs) of 1.77 (95% confidence interval [CI]: 1.19-2.64) and 1.92 (95% CI: 1.22-3.02), respectively. The authors conclude that vibration close to the "action levels" of published standards contribute to low back and neck pain. Vibration levels need to be assessed conservatively and control measures introduced.

Health risks of vibration exposure to wheelchair users in the community

PubMed Central

Garcia-Mendez, Yasmin; Pearlman, Jonathan L.; Boninger, Michael L.; Cooper, Rory A.

2013-01-01

Objective The purpose of this study was to evaluate whole-body vibration (WBV) exposure to wheelchair (WC) users in their communities and to determine the effect of WC frame type (folding, rigid, and suspension) in reducing WBV transmitted to the person. Design An observational case-control study of the WBV exposure levels among WC users. Participants Thirty-seven WC users, with no pressure sores, 18 years old or older and able to perform independent transfers. Main outcome measures WC users were monitored for 2 weeks to collect WBV exposure, as well as activity levels, by using custom vibration and activity data-loggers. Vibration levels were evaluated using ISO 2631-1 methods. Results All WC users who participated in this study were continuously exposed to WBV levels at the seat that were within and above the health caution zone specified by ISO 2631-1 during their day-to-day activities (0.83 ± 0.17 m/second2, weighted root-mean-squared acceleration, for 13.07 ± 3.85 hours duration of exposure). WCs with suspension did not attenuate vibration transmitted to WC users (V = 0.180, F(8, 56) = 0.692, P = 0.697). Conclusions WBV exposure to WC users exceeds international standards. Suspension systems need to be improved to reduce vibrations transmitted to the users. PMID:23820152

The Effect of Playing Different Musical Instruments on Arm Asymmetry

ERIC Educational Resources Information Center

Kaya, E. Erdem

2015-01-01

Between the two hemispheres of the brain, structural and functional differences are called cerebral lateralization that can affect the skill performance of both arms in a different way, which is called handedness. Approximately 90% of people are right-handed and they use the right hand for most skillful activities. Interestingly, recent studies…

Upper Limb Asymmetries in the Perception of Proprioceptively Determined Dynamic Position Sense

ERIC Educational Resources Information Center

Goble, Daniel J.; Brown, Susan H.

2010-01-01

Recent studies of position-related proprioceptive sense have provided evidence of a nonpreferred left arm advantage in right-handed individuals. The present study sought to determine whether similar asymmetries might exist in "dynamic position" sense. Thirteen healthy, right-handed adults were blindfolded and seated with arms placed on…

Short-Term Upper Limb Immobilization Affects Action-Word Understanding

ERIC Educational Resources Information Center

Bidet-Ildei, Christel; Meugnot, Aurore; Beauprez, Sophie-Anne; Gimenes, Manuel; Toussaint, Lucette

2017-01-01

The present study aimed to investigate whether well-established associations between action and language can be altered by short-term upper limb immobilization. The dominant arm of right-handed participants was immobilized for 24 hours with a rigid splint fixed on the hand and an immobilization vest restraining the shoulder, arm, and forearm. The…

Shoulder pain and concomitant hand oedema among stroke patients with pronounced arm paresis

PubMed Central

2013-01-01

Background The aim of this prospective study was to identify clinical factors associated with the development of shoulder pain in stroke patients with pronounced arm paresis. Methods At stroke onset, 485 patients were initially assessed in 2007–2009. Sixty-three patients with pronounced arm paresis completed the study, and 21 of these developed shoulder pain. Clinical findings were recorded fortnightly by the attending physiotherapist during hospital stay. Results Hand oedema on the paretic side was more common in patients developing shoulder pain compared with those who did not develop shoulder pain. The onset of shoulder pain was associated with concomitant hand oedema. High NIHSS score was associated with developing shoulder pain. Patients with a history of shoulder pain developed pain earlier than those without previous shoulder pain. Patients with haemorrhagic stroke were significantly more prone to developing shoulder pain. Conclusions One-third of the stroke patients with pronounced arm paresis developed shoulder pain. Concomitant hand oedema seems to be an additional symptom of shoulder injury. Patients with low general status are more vulnerable to develop post-stroke shoulder pain. PMID:24765589

Representation of continuous hand and arm movements in macaque areas M1, F5, and AIP: a comparative decoding study

NASA Astrophysics Data System (ADS)

Menz, Veera Katharina; Schaffelhofer, Stefan; Scherberger, Hansjörg

2015-10-01

Objective. In the last decade, multiple brain areas have been investigated with respect to their decoding capability of continuous arm or hand movements. So far, these studies have mainly focused on motor or premotor areas like M1 and F5. However, there is accumulating evidence that anterior intraparietal area (AIP) in the parietal cortex also contains information about continuous movement. Approach. In this study, we decoded 27 degrees of freedom representing complete hand and arm kinematics during a delayed grasping task from simultaneously recorded activity in areas M1, F5, and AIP of two macaque monkeys (Macaca mulatta). Main results. We found that all three areas provided decoding performances that lay significantly above chance. In particular, M1 yielded highest decoding accuracy followed by F5 and AIP. Furthermore, we provide support for the notion that AIP does not only code categorical visual features of objects to be grasped, but also contains a substantial amount of temporal kinematic information. Significance. This fact could be utilized in future developments of neural interfaces restoring hand and arm movements.

Arm-trunk coordination in wheelchair initiation displacement: A study of anticipatory and compensatory postural adjustments during different speeds and directions of propulsion.

PubMed

Chikh, Soufien; Garnier, Cyril; Faupin, Arnaud; Pinti, Antonio; Boudet, Samuel; Azaiez, Fairouz; Watelain, Eric

2018-06-01

Arm-trunk coordination during the initiation of displacement in manual wheelchair is a complex task. The objective of this work is to study the arm-trunk coordination by measuring anticipatory and compensatory postural adjustments. Nine healthy subjects participated in the study after being trained in manual wheelchair. They were asked to initiate a displacement in manual wheelchair in three directions (forward vs. left vs. right), with two speeds (spontaneous vs. maximum) and with two initial hand's positions (hands on thighs vs. hands on handrails). Muscular activities in the trunk (postural component) and the arms (focal component) were recorded bilaterally. The results show two strategies for trunk control: An anticipatory adjustment strategy and a compensatory adjustment strategy with a dominance of compensation. These two strategies are influenced by the finalities of displacement in terms of speed and direction depending on the hands positions. Arm-trunk coordination is characterized by an adaptability of anticipatory and compensatory postural adjustments. The study of this type of coordination for subjects with different levels of spinal cord injury could be used to predict the forthcoming displacement and thus assist the user in a complex task. Copyright © 2018 Elsevier Ltd. All rights reserved.

Air Bearing for Small Planar Vibrations

NASA Technical Reports Server (NTRS)

Wolf, M. F.

1985-01-01

Air-cushion device provides vibrations along axes 90 degrees apart. Bearing includes movable slide sandwiched between two fixed support plates. Separation between plates adjusted to standard air-bearing tolerances. Pressurized air supplied to slide so it floats between plates on cushion of air. Air exhausts on top and bottom surfaces of three arms of slide. Developed for stirring crystal-growth liquids in containers.

Reciprocal inhibition in writer's cramp.

PubMed

Chen, R S; Tsai, C H; Lu, C S

1995-09-01

We studied the inhibition of median H-reflexes by conditioning stimuli on the radial nerve in 13 patients with writer's cramp, eight of the simple type and five of the dystonic type, and in 14 normal volunteers. The patients and controls were right-handed, and their right arms were studied. Asymptomatic left arms were also studied in nine of 13 patients. In the control group we identified three periods of inhibition, with maximum peaks at conditioning-test intervals of 0 ms (41 +/- 17%), 20 ms (40 +/- 13%), and 100 ms (36 +/- 20%). In the patient group, the amplitudes of inhibition of these three periods in both arms were significantly less than those in the control group. However, there were no significant differences in the amplitudes of inhibition of these three periods between symptomatic and asymptomatic arms. There were also no significant differences between simple and dystonic writer's cramps. Our results indicate that the attenuation of reciprocal inhibition was present not only in symptomatic arms but also in asymptomatic arms of patients with writer's cramp. The defect of reciprocal inhibition in the asymptomatic hand has never been documented. We suggest that the preexistent electrophysiological abnormality may provide an explanation for the development of hand cramp after shifted writing.

Immediate effects of somatosensory stimulation on hand function in patients with poststroke hemiparesis: a randomized cross-over trial.

PubMed

Sim, Sun-Mi; Oh, Duck-Won; Chon, Seung-chul

2015-12-01

This study aimed to determine the immediate effects of somatosensory stimulation on hand function in patients with poststroke hemiparesis. Eleven patients with poststroke hemiparesis participated in this study. Four types (no stimulation, vibration, and light and rough touches) of somatosensory stimulation were performed randomly for 4 days applying only one type of somatosensory stimulation each day. The box and block test (BBT), the Jebsen-Taylor hand function test (JTHFT), hand grip strength (HGS), and movement distance and peak velocity of the wrist joint during a forward-reaching task were measured. The BBT and JTHFT scores for no stimulation [BBT: median (interquartile range), 0.00 (-1.00 to 1.00) and JTHFT: 2.57 (-0.47 to 4.92)] were significantly different from those for vibration [BBT: 3.00 (2.00-5.00) and JTHFT: -16.02 (-23.06 to -4.31)], light touch [BBT: 3.00 (1.00-4.00) and JTHFT: -5.00 (-21.20 to -0.94)], and rough touch [BBT: 2.00 (1.00-4.00) and JTHFT: -6.19 (-18.22 to -3.70)]. The JTHFT score was significantly higher for vibration than that for rough touch (P<0.05). The increase in HGS was significantly greater for light touch than that for no stimulation (P<0.05) and for vibration than that for light touch (P<0.05). There were significant differences for the sagittal and coronal planes in movement distance and for the sagittal and horizontal planes in peak velocity during the forward-reaching task (P<0.05). The findings suggest that somatosensory stimulation may be advantageous to improve the hand function of patients with poststroke hemiparesis, with more favorable effects observed in vibration stimulation.

Upper limb joint kinetics of three sitting pivot wheelchair transfer techniques in individuals with spinal cord injury

PubMed Central

Kankipati, Padmaja; Boninger, Michael L.; Gagnon, Dany; Cooper, Rory A.; Koontz, Alicia M.

2015-01-01

Study design Repeated measures design. Objective This study compared the upper extremity (UE) joint kinetics between three transfer techniques. Setting Research laboratory. Methods Twenty individuals with spinal cord injury performed three transfer techniques from their wheelchair to a level tub bench. Two of the techniques involved a head–hips method with leading hand position close (HH-I) and far (HH-A) from the body, and the third technique with the trunk upright (TU) and hand far from body. Motion analysis equipment recorded upper body movements and force sensors recorded their hand and feet reaction forces during the transfers. Results Several significant differences were found between HH-A and HH-I and TU and HH-I transfers indicating that hand placement was a key factor influencing the UE joint kinetics. Peak resultant hand, elbow, and shoulder joint forces were significantly higher for the HH-A and TU techniques at the trailing arm (P < 0.036) and lower at the leading arm (P < 0.021), compared to the HH-I technique. Conclusion Always trailing with the same arm if using HH-A or TU could predispose that arm to overuse related pain and injuries. Technique training should focus on initial hand placement close to the body followed by the amount of trunk flexion needed to facilitate movement. PMID:25130053

Robust Arm and Hand Tracking by Unsupervised Context Learning

PubMed Central

Spruyt, Vincent; Ledda, Alessandro; Philips, Wilfried

2014-01-01

Hand tracking in video is an increasingly popular research field due to the rise of novel human-computer interaction methods. However, robust and real-time hand tracking in unconstrained environments remains a challenging task due to the high number of degrees of freedom and the non-rigid character of the human hand. In this paper, we propose an unsupervised method to automatically learn the context in which a hand is embedded. This context includes the arm and any other object that coherently moves along with the hand. We introduce two novel methods to incorporate this context information into a probabilistic tracking framework, and introduce a simple yet effective solution to estimate the position of the arm. Finally, we show that our method greatly increases robustness against occlusion and cluttered background, without degrading tracking performance if no contextual information is available. The proposed real-time algorithm is shown to outperform the current state-of-the-art by evaluating it on three publicly available video datasets. Furthermore, a novel dataset is created and made publicly available for the research community. PMID:25004155

Effect of Transcranial Direct Current Stimulation on Severely Affected Arm-Hand Motor Function in Patients After an Acute Ischemic Stroke: A Pilot Randomized Control Trial.

PubMed

Rabadi, Meheroz H; Aston, Christopher E

2017-10-01

The aim of this article was to determine whether cathodal transcranial direct current stimulation (c-tDCS) to unaffected primary motor cortex (PMC) plus conventional occupational therapy (OT) improves functional motor recovery of the affected arm hand in patients after an acute ischemic stroke compared with sham transcranial direct current stimulation plus conventional OT. In this prospective, randomized, double-blinded, sham-controlled trial of 16 severe, acute ischemic stroke patients with severe arm-hand weakness were randomly assigned to either experimental (c-tDCS plus OT; n = 8) or control (sham transcranial direct current stimulation plus OT; n = 8) groups. All patients received a standard 3-hr in-patient rehabilitation therapy, plus an additional ten 30-min sessions of tDCS. During each session, 1 mA of cathodal stimulation to the unaffected PMC is performed followed by the patient's scheduled OT. The primary outcome measure was change in Action Research Arm Test (ARAT) total and subscores on discharge. Application of c-tDCS to unaffected PMC resulted in a clinically relevant 10-point improvement in the affected arm-hand function based on ARAT total score compared with a 2-point improvement in the control group. Application of 30-min of c-tDCS to the unaffected PMC showed a 10-point improvement in the ARAT score. This corresponds to a large effect size in improvement of affected arm-hand function in patients with severe, acute ischemic stroke. Although not statistically significant, this suggests that larger studies, enrolling at least 25 patients in each group, and with a longer follow-up are warranted.

Enhancement of Optical Adaptive Sensing by Using a Dual-Stage Seesaw-Swivel Actuator with a Tunable Vibration Absorber

PubMed Central

Chou, Po-Chien; Lin, Yu-Cheng; Cheng, Stone

2011-01-01

Technological obstacles to the use of rotary-type swing arm actuators to actuate optical pickup modules in small-form-factor (SFF) disk drives stem from a hinge’s skewed actuation, subsequently inducing off-axis aberrations and deteriorating optical quality. This work describes a dual-stage seesaw-swivel actuator for optical pickup actuation. A triple-layered bimorph bender made of piezoelectric materials (PZTs) is connected to the suspension of the pickup head, while the tunable vibration absorber (TVA) unit is mounted on the seesaw swing arm to offer a balanced force to reduce vibrations in a focusing direction. Both PZT and TVA are designed to satisfy stable focusing operation operational requirements and compensate for the tilt angle or deformation of a disc. Finally, simulation results verify the performance of the dual-stage seesaw-swivel actuator, along with experimental procedures and parametric design optimization confirming the effectiveness of the proposed system. PMID:22163877

Absence of equifinality of hand position in a double-step unloading task.

PubMed

Norouzi-Gheidari, Nahid; Archambault, Philippe

2010-08-01

Equifinality, during arm reaching movements, relates to the capacity of the neuromuscular system to attain the same final position in the presence or absence of transient perturbations. There have been several controversies regarding equifinality in the literature. A brief elastic perturbation, applied during a fast arm movement or just before its initiation, typically does not affect final arm position. On the other hand, several experiments have shown that velocity-dependent perturbations, such as Coriolis force or negative damping, while transient in nature, have a significant effect on final arm position when compared to unperturbed movements. In this study, an unloading paradigm was used to study the role of reflexes with respect to equifinality. The effects on final arm position of suddenly decreasing a static load maintained by fourteen subjects were analyzed. Subjects maintained an initial load produced by a double-joint manipulandum moving in the horizontal plane. The load was suddenly decreased, either in one or in two successive steps with different time intervals, resulting in a rapid reflex-mediated change in arm position. Unloading led to short-latency changes in the activity of shoulder and elbow muscles and significant variations in tonic activity. It was found that the final hand position was shorter for double- versus single-step unloading if the time between two successive changes in load was greater than 100 ms. With a shorter time interval, the final hand positions were the same. This difference in final hand positions was inversely proportional to the hand velocity at the time of the second change in load. Further, agonist/antagonist co-activation increased in double-step unloading. Thus, the change in both the load and the movement velocity may influence the magnitude of the unloading reflex. This may be indicative of a dependence of stretch reflexes on velocity. Perturbation may cause a reflex-mediated increase in joint stiffness, which could explain why equifinality is not preserved after some perturbations, such as velocity-dependant external forces.

Triggering of Carpal Tunnel Syndrome Symptoms in Patients Using Urban Public Transportation.

PubMed

de Saboya Lenzi, Luiz Guilherme; Fernandes, Carlos Henrique; Myiamoto Meirelles, Lia; Baptista Gomes Dos Santos, João; Faloppa, Flávio; Raduan Neto, Jorge

2016-09-01

Background: Carpal tunnel syndrome (CTS) is the most common compressive neuropathy found in clinical practice. Recent studies evaluated which external factors could be involved in the CTS symptoms, including prolonged exposure to vibration, especially in the upper limb. This study investigated signs and symptoms in patients with CTS after using urban transport on (1) both upper limbs, (2) how long before these symptoms appear, and (3) the hands position or body reaction during the act of pressing the safety bars. Methods: The study was conducted from July 2012 to April 2013. A total of 205 (178 women and 27 men) patients were evaluated. CTS was diagnosed in 285 hands. All participants answered a questionnaire formulated by the authors. The questionnaire was applied by researchers who were single-blinded and not involved in the research. Results: Most of the participants (87%) were women, but there was no statistical significance in age between groups (women = 51.24 ± 8.47 years, men = 51.10 ± 6.52 years, P > .05). The symptoms appeared significantly in the first 15 minutes after boarding when compared with patients who had no symptoms during the journey. There was no difference between hands position along the journey and the onset of symptoms. Conclusions: The onset of symptoms in patients with CTS using urban public transportation most commonly occurred in the first 15 minutes after boarding. Public transport vibration seems to be, at least in part, directly related to the development of symptoms. Questionnaires for the assessment of paresthesia symptoms during the use of public transport may be useful for CTS diagnosis.

Triggering of Carpal Tunnel Syndrome Symptoms in Patients Using Urban Public Transportation

PubMed Central

de Saboya Lenzi, Luiz Guilherme; Fernandes, Carlos Henrique; Myiamoto Meirelles, Lia; Baptista Gomes dos Santos, João; Faloppa, Flávio; Raduan Neto, Jorge

2016-01-01

Background: Carpal tunnel syndrome (CTS) is the most common compressive neuropathy found in clinical practice. Recent studies evaluated which external factors could be involved in the CTS symptoms, including prolonged exposure to vibration, especially in the upper limb. This study investigated signs and symptoms in patients with CTS after using urban transport on (1) both upper limbs, (2) how long before these symptoms appear, and (3) the hands position or body reaction during the act of pressing the safety bars. Methods: The study was conducted from July 2012 to April 2013. A total of 205 (178 women and 27 men) patients were evaluated. CTS was diagnosed in 285 hands. All participants answered a questionnaire formulated by the authors. The questionnaire was applied by researchers who were single-blinded and not involved in the research. Results: Most of the participants (87%) were women, but there was no statistical significance in age between groups (women = 51.24 ± 8.47 years, men = 51.10 ± 6.52 years, P > .05). The symptoms appeared significantly in the first 15 minutes after boarding when compared with patients who had no symptoms during the journey. There was no difference between hands position along the journey and the onset of symptoms. Conclusions: The onset of symptoms in patients with CTS using urban public transportation most commonly occurred in the first 15 minutes after boarding. Public transport vibration seems to be, at least in part, directly related to the development of symptoms. Questionnaires for the assessment of paresthesia symptoms during the use of public transport may be useful for CTS diagnosis. PMID:27698625

The Risk of Fractures Associated with Thiazolidinediones: A Self-controlled Case-Series Study

PubMed Central

Douglas, Ian J.; Evans, Stephen J.; Pocock, Stuart; Smeeth, Liam

2009-01-01

Background The results of clinical trials have suggested that the thiazolidinedione antidiabetic agents rosiglitazone and pioglitazone are associated with an increased risk of fractures, but such studies had limited power. The increased risk in these trials appeared to be limited to women and mainly involved fractures of the arm, wrist, hand, or foot: risk patterns that could not be readily explained. Our objective was to further investigate the risk of fracture associated with thiazolidinedione use. Methods and Findings The self-controlled case-series design was used to compare rates of fracture during thiazolidinedione exposed and unexposed periods and thus estimate within-person rate ratios. We used anonymised primary care data from the United Kingdom General Practice Research Database (GPRD). All patients aged 40 y or older with a recorded fracture and at least one prescription for a thiazolidinedione were included (n = 1,819). We found a within-person rate ratio of 1.43 (95% confidence interval [CI] 1.25–1.62) for fracture at any site comparing exposed with unexposed periods among patients prescribed any thiazolidinedione. This association was similar in men and women and in patients treated with either rosiglitazone or pioglitazone. The increased risk was also evident at a range of fracture sites, including hip, spine, arm, foot, wrist, or hand. The risk increased with increasing duration of thiazolidinedione exposure: rate ratio 2.00 (95% CI 1.48–2.70) for 4 y or more of exposure. Conclusion Within individuals who experience a fracture, fracture risk is increased during periods of exposure to thiazolidinediones (both rosiglitazone and pioglitazone) compared with unexposed periods. The increased risk is observed in both men and women and at a range of fracture sites. The risk also increases with longer duration of use. Please see later in the article for the Editors' Summary PMID:19787025

Intraoperative radiation exposure in spinal scoliosis surgery for pediatric patients using the O-arm® imaging system.

PubMed

Kobayashi, Kazuyoshi; Ando, Kei; Ito, Kenyu; Tsushima, Mikito; Morozumi, Masayoshi; Tanaka, Satoshi; Machino, Masaaki; Ota, Kyotaro; Ishiguro, Naoki; Imagama, Shiro

2018-05-01

The O-arm ® navigation system allows intraoperative CT imaging that can facilitate highly accurate instrumentation surgery, but radiation exposure is higher than with X-ray radiography. This is a particular concern in pediatric surgery. The purpose of this study is to examine intraoperative radiation exposure in pediatric spinal scoliosis surgery using O-arm. The subjects were 38 consecutive patients (mean age 12.9 years, range 10-17) with scoliosis who underwent spinal surgery with posterior instrumentation using O-arm. The mean number of fused vertebral levels was 11.0 (6-15). O-arm was performed before and after screw insertion, using an original protocol for the cervical, thoracic, and lumbar spine doses. The average scanning range was 6.9 (5-9) intervertebral levels per scan, with 2-7 scans per patient (mean 4.0 scans). Using O-arm, the dose per scan was 92.5 (44-130) mGy, and the mean total dose was 401 (170-826) mGy. This dose was 80.2% of the mean preoperative CT dose of 460 (231-736) mGy (P = 0.11). The total exposure dose and number of scans using intraoperative O-arm correlated strongly and significantly with the number of fused levels; however, there was no correlation with the patient's height. As the fused range became wider, several scans were required for O-arm, and the total radiation exposure became roughly the same as that in preoperative CT. Use of O-arm in our original protocol can contribute to reduction in radiation exposure.

Smart Hand For Manipulators

NASA Astrophysics Data System (ADS)

Fiorini, Paolo

1987-10-01

Sensor based, computer controlled end effectors for mechanical arms are receiving more and more attention in the robotics industry, because commonly available grippers are only adequate for simple pick and place tasks. This paper describes the current status of the research at JPL on a smart hand for a Puma 560 robot arm. The hand is a self contained, autonomous system, capable of executing high level commands from a supervisory computer. The mechanism consists of parallel fingers, powered by a DC motor, and controlled by a microprocessor embedded in the hand housing. Special sensors are integrated in the hand for measuring the grasp force of the fingers, and for measuring forces and torques applied between the arm and the surrounding environment. Fingers can be exercised under position, velocity and force control modes. The single-chip microcomputer in the hand executes the tasks of communication, data acquisition and sensor based motor control, with a sample cycle of 2 ms and a transmission rate of 9600 baud. The smart hand described in this paper represents a new development in the area of end effector design because of its multi-functionality and autonomy. It will also be a versatile test bed for experimenting with advanced control schemes for dexterous manipulation.

Mobile Phone Use Behaviors and Postures on Public Transportation Systems

PubMed Central

Liang, Huey-Wen; Hwang, Yaw-Huei

2016-01-01

Mobile phones are common in our daily life, but the users’ preferences for postures or screen operating styles have not been studied. This was a cross-sectional and observational study. We randomly sampled passengers who used mobile phones on the Mass Rapid Transit (MRT) system in metropolitan Taipei. A checklist was used to observe their body postures and screen operating styles while sitting or standing. As a result, 1,230 subjects from 400 trips were observed. Overall, of all the passengers who were sitting, 41% of them were using mobile phones. The majority of the tasks involved browsing (84%) with their phones in a portrait orientation (93%). Different-hand holding/operating was the most commonly used operating style while sitting (46%) and same-hand holding/operating was the most common while standing (46%). The distribution of screen operating styles was significantly different for those sitting than for those standing and for different genders and age groups. The most frequently observed postures while sitting were having one’s trunk against a backrest, feet on the floor and with or without an arm supported (58%). As for the users who were standing, the both- and different-hands groups had a high proportion of arms unsupported, feet on the floor and either their trunk supported or not. In contrast, the same-hand group tended to have their trunk unsupported, were holding a pole or handstrap and had both feet on floor. Further studies are warranted to characterize the ergonomic exposure of these commonly used postures and operating styles, and our results will help guide the selection of experimental conditions for laboratory settings. PMID:26828797

Assessment of vibration produced by the grinders used in the shipbuilding industry of Korea.

PubMed

Park, Hee-Sok; Yim, Sang-Hyuk

2007-04-01

The objective of this study is to estimate the prevalence of finger blanching among the workers in a shipyard of Korea using the dose-response relationship suggested by ISO 5349. The characteristics of vibration exposure produced by six types of grinders were investigated. Vibration measurement was made under the real work conditions. Exposure time was estimated by questionnaire and direct observation. In addition, cold provocation tests were performed, and the results from the tests were compared with the estimated prevalence. As a result, 4 hour-energy-equivalent frequency-weighted accelerations of the finishing grinding (FG) and the prepainting grinding (PG) jobs were 6.23 m/s(2) and 13.39 m/s(2), respectively. The mean exposure time for holding the grinders was 4.64 h per day. Using the ISO 5349 method, it was predicted that after exposure to vibration for 10.79 yr, about a half of the FG workers could develop finger blanching. For the PG workers, the corresponding predicted latency was 5.02 yr. A discrepancy was found between the results from the ISO relationship and those from the cold provocation tests. A linear regression model was suggested employing vibration acceleration and vibration exposure time as explanatory variables for vascular dysfunction.

Multiple direction vibration fixture

DOEpatents

Cericola, Fred; Doggett, James W.; Ernest, Terry L.; Priddy, Tommy G.

1991-01-01

An apparatus for simulating a rocket launch environment on a test item undergoing centrifuge testing by subjecting the item simultaneously or separately to vibration along an axis of centripetal force and along an axis perpendicular to the centripetal force axis. The apparatus includes a shaker motor supported by centrifuge arms and a right angle fixture pivotally connected to one of the shaker motor mounts. When the shaker motor vibrates along the centripetal force axis, the vibrations are imparted to a first side of the right angle fixture. The vibrations are transmitted 90 degrees around the pivot and are directed to a second side of the right angle fixture which imparts vibrations perpendicular to the centripetal force axis. The test item is in contact with a third side of the right angle fixture and receives both centripetal-force-axis vibrations and perpendicular axis vibrations simultaneously. A test item can be attached to the third side near the flexible coupling or near the air bag to obtain vibrations along the centripetal force axis or transverse to the centripetal force axis.

Adaptive Strategies for Controls of Flexible Arms. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Yuan, Bau-San

1989-01-01

An adaptive controller for a modern manipulator has been designed based on asymptotical stability via the Lyapunov criterion with the output error between the system and a reference model used as the actuating control signal. Computer simulations were carried out to test the design. The combination of the adaptive controller and a system vibration and mode shape estimator show that the flexible arm should move along a pre-defined trajectory with high-speed motion and fast vibration setting time. An existing computer-controlled prototype two link manipulator, RALF (Robotic Arm, Large Flexible), with a parallel mechanism driven by hydraulic actuators was used to verify the mathematical analysis. The experimental results illustrate that assumed modes found from finite element techniques can be used to derive the equations of motion with acceptable accuracy. The robust adaptive (modal) control is implemented to compensate for unmodelled modes and nonlinearities and is compared with the joint feedback control in additional experiments. Preliminary results show promise for the experimental control algorithm.

Position sense at the human forearm in the horizontal plane during loading and vibration of elbow muscles

PubMed Central

Ansems, G E; Allen, T J; Proske, U

2006-01-01

When blindfolded subjects match the position of their forearms in the vertical plane they rely on signals coming from the periphery as well as from the central motor command. The command signal provides a positional cue from the accompanying effort sensation required to hold the arm against gravity. Here we have asked, does a centrally generated effort signal contribute to position sense in the horizontal plane, where gravity cannot play a role? Blindfolded subjects were required to match forearm position for the unloaded arm and when flexors or extensors were bearing 10%, 25% or 40% of maximum loads. Before each match the reference arm was conditioned by contracting elbow muscles while the arm was held flexed or extended. For the unloaded arm conditioning led to a consistent pattern of errors which was attributed to signals from flexor and extensor muscle spindles. When elbow muscles were loaded the errors from conditioning converged, presumably because the spindles had become coactivated through the fusimotor system during the load-bearing contraction. However, this convergence was seen only when subjects supported a static load. When they moved the load differences in errors from conditioning persisted. Muscle vibration during load bearing or moving a load did not alter the distribution of errors. It is concluded that for position sense of an unloaded arm in the horizontal plane the brain relies on signals from muscle spindles. When the arm is loaded, an additional signal of central origin contributes, but only if the load is moved. PMID:16873408

Dexterous programmable robot and control system

NASA Astrophysics Data System (ADS)

Engler, Charles D., Jr.

1995-09-01

An anatomically correct, humanlike, mechanical arm and hand is provided that an operator can control to perform with the dexterity and compliance of a human hand. Being humanlike and robotic enhances the device's control and gripper dexterity. Control of the movement of the arm and hand is performed or guided by a 'teach glove' worn by the operator. As he or she performs some hand manipulation, a controller stores signals from sensors on the exoskeleton. The sensors monitor the operator's finger-joint movement positions. These values are later translated into actuator control signals for servomotors, eventually duplicating the operator's movement.

Physical and psychosocial ergonomic risk factors for low back pain in automobile manufacturing workers.

PubMed

Vandergrift, Jonathan L; Gold, Judith E; Hanlon, Alexandra; Punnett, Laura

2012-01-01

To examine the association between ergonomic physical and psychosocial exposures and the risk of prevalent and incident low back pain (LBP) in a longitudinal cohort of automobile manufacturing workers. Ergonomic exposure intensity and LBP presence were determined through questionnaires at baseline (n=1181) and to workers in the same job 1 year later (n=505). Models were constructed using log-binomial regression with special attention to interactions between ergonomic exposures. Awkward back posture (prevalence ratio (PR) 1.12, 95% CI 1.07 to 1.17), hand force (PR 1.06, 95% CI 1.02 to 1.10), physical effort (PR 1.10, 95% CI 1.04 to 1.16) and whole body vibration (PR 1.04, 95% CI 1.01 to 1.08) were each associated cross-sectionally with LBP. Awkward back posture (RR 1.13, 95% CI 0.98 to 1.31) and hand force (RR 1.07, 95% CI 0.93 to 1.22) also predicted incident LBP, although estimates were statistically less precise. Neither job control, psychological demands, nor job strain was independently related to risk of incident LBP. Among participants reporting high physical ergonomic exposures and moderate to high job control, increasing job demands was associated with a reduced LBP risk (RR 0.72, 95% CI 0.52 to 1.00). Among participants reporting high physical exposures and low job control, psychological demands was associated with an increased LBP risk (RR 1.30, 95% CI 1.02 to 1.66). Psychosocial workplace interventions for LBP should prioritise jobs in which there are high physical ergonomic exposures. Future studies of LBP should examine the interactions between physical ergonomic risk factors.

Ready steady push--a study of the role of arm posture in manual exertions.

PubMed

Okunribido, Olanrewaju O; Haslegrave, Christine M

2008-02-01

This study investigated arm posture and hand forces during bi-manual pushing. Nine male and eight female participants performed isometric exertions at two reach distances (0 and elbow-grip) and six different positions of the hand interface (handle), defined by the plane (longitudinal, lateral, horizontal) and orientation (0 degrees and 45 degrees). Electrogoniometer instruments were used to measure the displacements/postures of the wrist and elbow joints and the forearm, and force measuring strain gauges were used to measure the exerted hand forces (x-, y- and z-components). The results showed that ability to vary arm posture, particularly the forearm, is important during build up of force and that people tend to seek for a balance in the forces applied at the hands by exerting more in the vertical direction. Also, lateral plane handle positions permitted exertion of greater forces than longitudinal and horizontal plane positions.

Characterization of the frequency and muscle responses of the lumbar and thoracic spines of seated volunteers during sinusoidal whole body vibration.

PubMed

Baig, Hassam A; Dorman, Daniel B; Bulka, Ben A; Shivers, Bethany L; Chancey, Valeta C; Winkelstein, Beth A

2014-10-01

Whole body vibration has been postulated to contribute to the onset of back pain. However, little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to measure the frequency and corresponding muscle responses of seated male volunteers during whole body vibration exposures along the vertical and anteroposterior directions to define the transmissibility and associated muscle activation responses for relevant whole body vibration exposures. Seated human male volunteers underwent separate whole body vibration exposures in the vertical (Z-direction) and anteroposterior (X-direction) directions using sinusoidal sweeps ranging from 2 to 18 Hz, with a constant amplitude of 0.4 g. For each vibration exposure, the accelerations and displacements of the seat and lumbar and thoracic spines were recorded. In addition, muscle activity in the lumbar and thoracic spines was recorded using electromyography (EMG) and surface electrodes in the lumbar and thoracic region. Transmissibility was determined, and peak transmissibility, displacement, and muscle activity were compared in each of the lumbar and thoracic regions. The peak transmissibility for vertical vibrations occurred at 4 Hz for both the lumbar (1.55 ± 0.34) and thoracic (1.49 ± 0.21) regions. For X-directed seat vibrations, the transmissibility ratio in both spinal regions was highest at 2 Hz but never exceeded a value of 1. The peak muscle response in both spinal regions occurred at frequencies corresponding to the peak transmissibility, regardless of the direction of imposed seat vibration: 4 Hz for the Z-direction and 2-3 Hz for the X-direction. In both vibration directions, spinal displacements occurred primarily in the direction of seat vibration, with little off-axis motion. The occurrence of peak muscle responses at frequencies of peak transmissibility suggests that such frequencies may induce greater muscle activity, leading to muscle fatigue, which could be a contributing mechanism of back pain.

REAL-TIME FEEDBACK FOR IMPROVING COMPLIANCE TO HAND SANITIZATION AMONG HEALTHCARE WORKERS IN AN OPEN LAYOUT ICU USING RADIOFREQUENCY IDENTIFICATION

PubMed Central

Waghmare, Abijeet; Ekstrand, Maria; Raj, Tony; Selvam, Sumithra; Sreerama, Sai Madhukar; Sampath, Sriram

2015-01-01

Objective To increase hand sanitizer usage among healthcare workers by developing and implementing a low-cost intervention using RFID and wireless mesh networks to provide real-time alarms for increasing hand hygiene compliance during opportune moments in an open layout Intensive Care Unit (ICU). Method A wireless, RFID based system was developed and deployed in the ICU. The ICU beds were divded into an intervention arm (n=10) and a control arm (n=14). Passive RFID tags were issued to the doctors, nurses and support staff of the ICU. Long range RFID readers were positioned strategically. Sensors were placed beneath the hand sanitizers to record sanitizer usage. The system would alert the HCWs by flashing a light if an opportune moment for hand sanitization was detected. Results A significant increase in hand sanitizer use was noted in the intervention arm. Usage was highest during the early part of the workday and decreased as the day progressed. Hand wash events per person hour was highest among the ancilliary staff followed by the doctors and nurses. Conclusion Real-time feedback has potential to increase hand hygiene compliance among HCWs. The system demonstrates the possibility of automating compliance monitoring in an ICU with an open layout. PMID:25957165

Real-time feedback for improving compliance to hand sanitization among healthcare workers in an open layout ICU using radiofrequency identification.

PubMed

Radhakrishna, Kedar; Waghmare, Abijeet; Ekstrand, Maria; Raj, Tony; Selvam, Sumithra; Sreerama, Sai Madhukar; Sampath, Sriram

2015-06-01

The aim of this study is to increase hand sanitizer usage among healthcare workers by developing and implementing a low-cost intervention using RFID and wireless mesh networks to provide real-time alarms for increasing hand hygiene compliance during opportune moments in an open layout Intensive Care Unit (ICU). A wireless, RFID based system was developed and implemented in the ICU. The ICU beds were divded into an intervention arm (n = 10) and a control arm (n = 14). Passive RFID tags were issued to the doctors, nurses and support staff of the ICU. Long range RFID readers were positioned strategically. Sensors were placed beneath the hand sanitizers to record sanitizer usage. The system would alert the HCWs by flashing a light if an opportune moment for hand sanitization was detected. A significant increase in hand sanitizer use was noted in the intervention arm. Usage was highest during the early part of the workday and decreased as the day progressed. Hand wash events per person hour was highest among the ancilliary staff followed by the doctors and nurses. Real-time feedback has potential to increase hand hygiene compliance among HCWs. The system demonstrates the possibility of automating compliance monitoring in an ICU with an open layout.

The Relation of Hand and Arm Configuration Variances while Tracking Geometric Figures in Parkinson's Disease: Aspects for Rehabilitation

ERIC Educational Resources Information Center

Keresztenyi, Zoltan; Cesari, Paola; Fazekas, Gabor; Laczko, Jozsef

2009-01-01

Variances of drawing arm movements between patients with Parkinson's disease and healthy controls were compared. The aim was to determine whether differences in joint synergies or individual joint rotations affect the endpoint (hand position) variance. Joint and endpoint coordinates were measured while participants performed drawing tasks.…

Arm and Hand Movement in Children Suspected of Having Autism Spectrum Disorder

ERIC Educational Resources Information Center

Braddock, Barbara A.; Hilton, Jane C.

2016-01-01

The aim of this study was to describe arm and hand movement in children suspected of having autism spectrum disorder (ASD; age range 29-43 months). A videotaped retrospective review of five children with symptoms of ASD during "Communication Temptation Tasks" was completed at two time points (pre-testing and 6 weeks later). Categories of…

Dynamic control modification techniques in teleoperation of a flexible manipulator. M.S. Thesis

NASA Technical Reports Server (NTRS)

Magee, David Patrick

1991-01-01

The objective of this research is to reduce the end-point vibration of a large, teleoperated manipulator while preserving the usefulness of the system motion. A master arm is designed to measure desired joint angles as the user specifies a desired tip motion. The desired joint angles from the master arm are the inputs to an adaptive PD control algorithm that positions the end-point of the manipulator. As the user moves the tip of the master, the robot will vibrate at its natural frequencies which makes it difficult to position the end-point. To eliminate the tip vibration during teleoperated motions, an input shaping method is presented. The input shaping method transforms each sample of the desired input into a new set of impulses that do not excite the system resonances. The method is explained using the equation of motion for a simple, second-order system. The impulse response of such a system is derived and the constraint equations for vibrationless motion are presented. To evaluate the robustness of the method, a different residual vibration equation from Singer's is derived that more accurately represents the input shaping technique. The input shaping method is shown to actually increase the residual vibration in certain situations when the system parameters are not accurately specified. Finally, the implementation of the input shaping method to a system with varying parameters is shown to induce a vibration into the system. To eliminate this vibration, a modified command shaping technique is developed. The ability of the modified command shaping method to reduce vibration at the system resonances is tested by varying input perturbations to trajectories in a range of possible user inputs. By comparing the frequency responses of the transverse acceleration at the end-point of the manipulator, the modified method is compared to the original PD routine. The control scheme that produces the smaller magnitude of resonant vibration at the first natural frequency is considered the more effective control method.

Effect of tactile vibration on annoyance to synthesized propfan noise

NASA Technical Reports Server (NTRS)

Clevenson, S. A.

1981-01-01

Design information that maximizes passenger comfort for propfan aircraft is presented. Predicted noise and vibration environments and the resultant passenger acceptability were studied. The effect of high frequency tactile vibration (i.e., greater than 30 Hz) on passenger reactions was analyzed. Passenger reactions to a wide range of noise with and without tactile vibration was studied. The passenger ride quality simulator was employed using subjects who evaluated either synthesized propeller noises only, or these noises combined with seat/arm vibration. The noises ranging from 80-100 dB consisted of a turbulent boundary layer noise with a factorial combination of five blade passage frequencies (50-200 Hz), two harmonic rolloffs, and three tone/noise ratios. It is indicated that passenger reaction (annoyance) to noise is not significantly changed in the presence of tactile vibration.

Quantification of the effects of audible rattle and source type on the human response to environmental vibration.

PubMed

Woodcock, J; Sica, G; Peris, E; Sharp, C; Moorhouse, A T; Waddington, D C

2016-03-01

The present research quantifies the influence of source type and the presence of audible vibration-induced rattle on annoyance caused by vibration in residential environments. The sources of vibration considered are railway and the construction of a light rail system. Data were measured in the United Kingdom using a socio-vibration survey (N = 1281). These data are analyzed using ordinal logit models to produce exposure-response relationships describing community annoyance as a function of vibration exposure. The influence of source type and the presence of audible vibration-induced rattle on annoyance are investigated using dummy variable analysis, and quantified using odds-ratios and community tolerance levels. It is concluded that the sample population is more likely to express higher levels of annoyance if the vibration source is construction compared to railway, and if vibration-induced rattle is audible.

Virtual Hand Illusion Induced by Visuomotor Correlations

PubMed Central

Sanchez-Vives, Maria V.; Spanlang, Bernhard; Frisoli, Antonio; Bergamasco, Massimo; Slater, Mel

2010-01-01

Background Our body schema gives the subjective impression of being highly stable. However, a number of easily-evoked illusions illustrate its remarkable malleability. In the rubber-hand illusion, illusory ownership of a rubber-hand is evoked by synchronous visual and tactile stimulation on a visible rubber arm and on the hidden real arm. Ownership is concurrent with a proprioceptive illusion of displacement of the arm position towards the fake arm. We have previously shown that this illusion of ownership plus the proprioceptive displacement also occurs towards a virtual 3D projection of an arm when the appropriate synchronous visuotactile stimulation is provided. Our objective here was to explore whether these illusions (ownership and proprioceptive displacement) can be induced by only synchronous visuomotor stimulation, in the absence of tactile stimulation. Methodology/Principal Findings To achieve this we used a data-glove that uses sensors transmitting the positions of fingers to a virtually projected hand in the synchronous but not in the asynchronous condition. The illusion of ownership was measured by means of questionnaires. Questions related to ownership gave significantly larger values for the synchronous than for the asynchronous condition. Proprioceptive displacement provided an objective measure of the illusion and had a median value of 3.5 cm difference between the synchronous and asynchronous conditions. In addition, the correlation between the feeling of ownership of the virtual arm and the size of the drift was significant. Conclusions/Significance We conclude that synchrony between visual and proprioceptive information along with motor activity is able to induce an illusion of ownership over a virtual arm. This has implications regarding the brain mechanisms underlying body ownership as well as the use of virtual bodies in therapies and rehabilitation. PMID:20454463

Production, Delivery and Application of Vibration Energy in Healthcare

NASA Astrophysics Data System (ADS)

Abundo, Paolo; Trombetta, Chiara; Foti, Calogero; Rosato, Nicola

2011-02-01

In Rehabilitation Medicine therapeutic application of vibration energy in specific clinical treatments and in sport rehabilitation is being affirmed more and more.Vibration exposure can have positive or negative effects on the human body depending on the features and time of the characterizing wave. The human body is constantly subjected to different kinds of vibrations, inducing bones and muscles to actively modify their structure and metabolism in order to fulfill the required functions. Like every other machine, the body supports only certain vibration energy levels over which long term impairments can be recognized. As shown in literature anyway, short periods of vibration exposure and specific frequency values can determine positive adjustments.

Actuator and electronics packaging for extrinsic humanoid hand

NASA Technical Reports Server (NTRS)

Ihrke, Chris A. (Inventor); Bridgwater, Lyndon (Inventor); Diftler, Myron A. (Inventor); Reich, David M. (Inventor); Askew, Scott R. (Inventor)

2013-01-01

The lower arm assembly for a humanoid robot includes an arm support having a first side and a second side, a plurality of wrist actuators mounted to the first side of the arm support, a plurality of finger actuators mounted to the second side of the arm support and a plurality of electronics also located on the first side of the arm support.

Low back pain in drivers: The relative role of whole-body vibration, posture and manual materials handling

NASA Astrophysics Data System (ADS)

Okunribido, O. O.; Magnusson, M.; Pope, M. H.

2006-12-01

A cross-sectional study was conducted to investigate the relative role of whole-body vibration (WBV), posture and manual materials handling (MMH) as risk factors for low back pain (LBP). Using a validated questionnaire, information about health history, posture and MMH performed was obtained from 394 workers who drove vehicles as part of their job (according to seven predefined occupational groups) and 59 who did not. The intention was to reflect a wide range of exposures with the lower end of the exposure spectrum defined as that of non-manual workers who do not drive as part of their job. Based on the questionnaire responses and direct measurements of vibration exposure, personal aggregate measures of exposure were computed for each of the respondents, i.e., total vibration dose (TVD), posture score (PS) and manual handling score (MHS). Odds ratios (and 95% confidence intervals) for back pain were obtained from logistics regression models and log-linear backward elimination analysis was performed. The findings showed that 'combined exposure' due to posture and one or both of vibration and MMH, rather than the individual exposure to one of the three factors (WBV, posture, MMH) is the main contributor of the increased prevalence of LBP.

Virtual Reality to Maximize Function for Hand and Arm Rehabilitation: Exploration of Neural Mechanisms

PubMed Central

MERIANS, Alma S.; TUNIK, Eugene; ADAMOVICH, Sergei V.

2015-01-01

Stroke patients report hand function as the most disabling motor deficit. Current evidence shows that learning new motor skills is essential for inducing functional neuroplasticity and functional recovery. Adaptive training paradigms that continually and interactively move a motor outcome closer to the targeted skill are important to motor recovery. Computerized virtual reality simulations when interfaced with robots, movement tracking and sensing glove systems are particularly adaptable, allowing for online and offline modifications of task based activities using the participant’s current performance and success rate. We have developed a second generation system that can exercise the hand and the arm together or in isolation and provides for both unilateral and bilateral hand and arm activities in three-dimensional space. We demonstrate that by providing haptic assistance for the hand and arm and adaptive anti-gravity support, the system can accommodate patients with lower level impairments. We hypothesize that combining training in VE with observation of motor actions can bring additional benefits. We present a proof of concept of a novel system that integrates interactive VE with functional neuroimaging to address this issue. Three components of this system are synchronized, the presentation of the visual display of the virtual hands, the collection of fMRI images and the collection of hand joint angles from the instrumented gloves. We show that interactive VEs can facilitate activation of brain areas during training by providing appropriately modified visual feedback. We predict that visual augmentation can become a tool to facilitate functional neuroplasticity. PMID:19592790

Results of Clinicians Using a Therapeutic Robotic System in an Inpatient Stroke Rehabilitation Unit

PubMed Central

2011-01-01

Background Physical rehabilitation is an area where robotics could contribute significantly to improved motor return for individuals following a stroke. This paper presents the results of a preliminary randomized controlled trial (RCT) of a robot system used in the rehabilitation of the paretic arm following a stroke. Methods The study's objectives were to explore the efficacy of this new type of robotic therapy as compared to standard physiotherapy treatment in treating the post-stroke arm; to evaluate client satisfaction with the proposed robotic system; and to provide data for sample size calculations for a proposed larger multicenter RCT. Twenty clients admitted to an inpatient stroke rehabilitation unit were randomly allocated to one of two groups, an experimental (robotic arm therapy) group or a control group (conventional therapy). An occupational therapist blinded to patient allocation administered two reliable measures, the Chedoke Arm and Hand Activity Inventory (CAHAI-7) and the Chedoke McMaster Stroke Assessment of the Arm and Hand (CMSA) at admission and discharge. For both groups, at admission, the CMSA motor impairment stage of the affected arm was between 1 and 3. Results Data were compared to determine the effectiveness of robot-assisted versus conventional therapy treatments. At the functional level, both groups performed well, with improvement in scores on the CAHAI-7 showing clinical and statistical significance. The CAHAI-7 (range7-49) is a measure of motor performance using functional items. Individuals in the robotic therapy group, on average, improved by 62% (95% CI: 26% to 107%) while those in the conventional therapy group changed by 30% (95% CI: 4% to 61%). Although performance on this measure is influenced by hand recovery, our results showed that both groups had similar stages of motor impairment in the hand. Furthermore, the degree of shoulder pain, as measured by the CMSA pain inventory scale, did not worsen for either group over the course of treatment. Conclusion Our findings indicated that robotic arm therapy alone, without additional physical therapy interventions tailored to the paretic arm, was as effective as standard physiotherapy treatment for all responses and more effective than conventional treatment for the CMSA Arm (p = 0.04) and Hand (p = 0.04). At the functional level, both groups performed equally well. PMID:21871095

Results of clinicians using a therapeutic robotic system in an inpatient stroke rehabilitation unit.

PubMed

Abdullah, Hussein A; Tarry, Cole; Lambert, Cynthia; Barreca, Susan; Allen, Brian O

2011-08-26

Physical rehabilitation is an area where robotics could contribute significantly to improved motor return for individuals following a stroke. This paper presents the results of a preliminary randomized controlled trial (RCT) of a robot system used in the rehabilitation of the paretic arm following a stroke. The study's objectives were to explore the efficacy of this new type of robotic therapy as compared to standard physiotherapy treatment in treating the post-stroke arm; to evaluate client satisfaction with the proposed robotic system; and to provide data for sample size calculations for a proposed larger multicenter RCT. Twenty clients admitted to an inpatient stroke rehabilitation unit were randomly allocated to one of two groups, an experimental (robotic arm therapy) group or a control group (conventional therapy). An occupational therapist blinded to patient allocation administered two reliable measures, the Chedoke Arm and Hand Activity Inventory (CAHAI-7) and the Chedoke McMaster Stroke Assessment of the Arm and Hand (CMSA) at admission and discharge. For both groups, at admission, the CMSA motor impairment stage of the affected arm was between 1 and 3. Data were compared to determine the effectiveness of robot-assisted versus conventional therapy treatments. At the functional level, both groups performed well, with improvement in scores on the CAHAI-7 showing clinical and statistical significance. The CAHAI-7 (range7-49) is a measure of motor performance using functional items. Individuals in the robotic therapy group, on average, improved by 62% (95% CI: 26% to 107%) while those in the conventional therapy group changed by 30% (95% CI: 4% to 61%). Although performance on this measure is influenced by hand recovery, our results showed that both groups had similar stages of motor impairment in the hand. Furthermore, the degree of shoulder pain, as measured by the CMSA pain inventory scale, did not worsen for either group over the course of treatment. Our findings indicated that robotic arm therapy alone, without additional physical therapy interventions tailored to the paretic arm, was as effective as standard physiotherapy treatment for all responses and more effective than conventional treatment for the CMSA Arm (p = 0.04) and Hand (p = 0.04). At the functional level, both groups performed equally well.

Tool-specific performance of vibration-reducing gloves for attenuating fingers-transmitted vibration

PubMed Central

Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.

2016-01-01

BACKGROUND Fingers-transmitted vibration can cause vibration-induced white finger. The effectiveness of vibration-reducing (VR) gloves for reducing hand transmitted vibration to the fingers has not been sufficiently examined. OBJECTIVE The objective of this study is to examine tool-specific performance of VR gloves for reducing finger-transmitted vibrations in three orthogonal directions (3D) from powered hand tools. METHODS A transfer function method was used to estimate the tool-specific effectiveness of four typical VR gloves. The transfer functions of the VR glove fingers in three directions were either measured in this study or during a previous study using a 3D laser vibrometer. More than seventy vibration spectra of various tools or machines were used in the estimations. RESULTS When assessed based on frequency-weighted acceleration, the gloves provided little vibration reduction. In some cases, the gloves amplified the vibration by more than 10%, especially the neoprene glove. However, the neoprene glove did the best when the assessment was based on unweighted acceleration. The neoprene glove was able to reduce the vibration by 10% or more of the unweighted vibration for 27 out of the 79 tools. If the dominant vibration of a tool handle or workpiece was in the shear direction relative to the fingers, as observed in the operation of needle scalers, hammer chisels, and bucking bars, the gloves did not reduce the vibration but increased it. CONCLUSIONS This study confirmed that the effectiveness for reducing vibration varied with the gloves and the vibration reduction of each glove depended on tool, vibration direction to the fingers, and finger location. VR gloves, including certified anti-vibration gloves do not provide much vibration reduction when judged based on frequency-weighted acceleration. However, some of the VR gloves can provide more than 10% reduction of the unweighted vibration for some tools or workpieces. Tools and gloves can be matched for better effectiveness for protecting the fingers. PMID:27867313

A zero phase adaptive fuzzy Kalman filter for physiological tremor suppression in robotically assisted minimally invasive surgery.

PubMed

Sang, Hongqiang; Yang, Chenghao; Liu, Fen; Yun, Jintian; Jin, Guoguang; Chen, Fa

2016-12-01

Hand physiological tremor of surgeons can cause vibration at the surgical instrument tip, which may make it difficult for the surgeon to perform fine manipulations of tissue, needles, and sutures. A zero phase adaptive fuzzy Kalman filter (ZPAFKF) is proposed to suppress hand tremor and vibration of a robotic surgical system. The involuntary motion can be reduced by adding a compensating signal that has the same magnitude and frequency but opposite phase with the tremor signal. Simulations and experiments using different filters were performed. Results show that the proposed filter can avoid the loss of useful motion information and time delay, and better suppress minor and varying tremor. The ZPAFKF can provide less error, preferred accuracy, better tremor estimation, and more desirable compensation performance, to suppress hand tremor and decrease vibration at the surgical instrument tip. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Neuropathic Pain-like Alterations in Muscle Nociceptor Function Associated with Vibration-induced Muscle Pain

PubMed Central

Chen, Xiaojie; Green, Paul G.; Levine, Jon D.

2010-01-01

We recently developed a rodent model of the painful muscle disorders induced by occupational exposure to vibration. In the present study we used this model to evaluate the function of sensory neurons innervating the vibration-exposed gastrocnemius muscle. Activity of 74 vibration-exposed and 40 control nociceptors, with mechanical receptive fields in the gastrocnemius muscle, were recorded. In vibration-exposed rats ~15% of nociceptors demonstrated an intense and long-lasting barrage of action potentials in response to sustained suprathreshold mechanical stimulation (average of 2635 action potentials with frequency of ~44 Hz during a 1 minute suprathreshold stimulus) much greater than has been reported to be produced even by potent inflammatory mediators. While these high-firing nociceptors had lower mechanical thresholds than the remaining nociceptors, exposure to vibration had no effect on conduction velocity and did not induce spontaneous activity. Hyperactivity was not observed in any of 19 neurons from vibration exposed rats pretreated with intrathecal antisense for the IL-6 receptor subunit gp130. Since vibration can injure peripheral nerves, and IL-6 has been implicated in painful peripheral neuropathies, we suggest that the dramatic change in sensory neuron function and development of muscles pain, induced by exposure to vibration, reflects a neuropathic muscle pain syndrome. PMID:20800357

Synergy effects of combined multichannel EMG-triggered electrical stimulation and mirror therapy in subacute stroke patients with severe or very severe arm/hand paresis.

PubMed

Schick, Thomas; Schlake, Hans-Peter; Kallusky, Juliane; Hohlfeld, Günter; Steinmetz, Maria; Tripp, Florian; Krakow, Karsten; Pinter, Michaela; Dohle, Christian

2017-01-01

Neurorehabilitation requires the development of severity-dependent and successful therapies for arm/hand rehabilitation in stroke patients. To evaluate the effectiveness of adding mirror therapy to bilateral EMG-triggered multi-channel electrostimulation for the treatment of severe arm/hand paresis in stroke patients. The subjects of this randomized, controlled, multicentre study were stroke patients who had suffered their first insult between 1 and 6 months before study start and had severe or very severe arm/hand paresis, as classified by Fugl-Meyer-Assessment. Subjects were randomly allocated to an intervention group (n = 16) or control group (n = 17). Both groups were treated for 3 weeks (5x week, 30 minutes) with bilateral EMG-triggered multi-channel electrostimulation. The intervention group additionally received mirror feedback of the unaffected limb. The primary outcome measure was motor recovery of the upper extremities, as measured by the Fugl-Meyer Assessment. The Intervention Group with very severe paresis had significantly better motor recovery in total Fugl-Meyer Assessment (p = 0.017) at a medium effect size (Cohen) of d = 0.7, due to a significant recovery of shoulder and elbow function (p = 0.003) in the Fugl-Meyer Assessment Part A subtest. For subjects with severe paresis, additional mirror therapy did not significantly influence outcome. Additional mirror therapy in combination with EMG-triggered multi-channel electrostimulation is therapeutically beneficial for post-acute stroke patients with very severe arm/hand paresis.

Targeted Muscle Reinnervation for Real-Time Myoelectric Control of Multifunction Artificial Arms

PubMed Central

Kuiken, Todd A.; Li, Guanglin; Lock, Blair A.; Lipschutz, Robert D.; Miller, Laura A.; Stubblefield, Kathy A.; Englehart, Kevin

2011-01-01

Context Improving the function of prosthetic arms remains a challenge, as access to the neural control information for the arm is lost during amputation. We have developed a surgical technique called targeted muscle reinnervation (TMR) which transfers residual arm nerves to alternative muscle sites. After reinnervation, these target muscles produce an electromyogram (EMG) on the surface of the skin that can be measured and used to control prosthetic arms. Objective Assess the performance of TMR upper-limb amputee patients using a pattern-recognition algorithm to decode EMG signals and control prosthetic arm motions. Design Surface EMG signals were recorded on participants and decoded using a pattern-recognition algorithm. The decoding program controlled the movement of a virtual prosthetic arm. Participants were instructed to perform various arm movements, and their abilities to control the virtual prosthetic arm were measured. In addition, TMR patients used the same control system to operate advanced arm prosthesis prototypes. Setting This study was conducted between January 2007 and January 2008 at the Rehabilitation Institute of Chicago. Participants This study included five patients with shoulder disarticulation or transhumeral amputations who received TMR surgery between February 2002 and October 2006. It also included five non-amputee (control) participants. Main Outcome Measure Performance metrics measured during virtual arm movements included motion-selection time, motion-completion time, and motion-completion (or `success') rate. Three of the TMR patients were also able to test advanced arm prostheses. Results TMR patients were able to repeatedly perform 10 different elbow, wrist and hand motions with the virtual prosthetic arm. For TMR patients, the average (standard deviation (SD)) motion-selection and motion-completion times for elbow and wrist movements were 0.22 s (0.06) and 1.29 s (0.15), respectively. These times were 0.06 s and 0.21 s longer than the average times of control participants. For TMR patients, the average (SD) motion-selection and motion-completion times for hand-grasp patterns were 0.38 s (0.12) and 1.54 s (0.27), respectively. TMR patients successfully completed an average (SD) of 96.3% (3.8) of elbow and wrist movements and 86.9% (13.9) of hand movements within 5 s, compared to 100% (0) and 96.7% (4.7) completed by controls. Three of the patients were able to demonstrate the use of this control system in advanced prostheses including motorized shoulders, elbows, wrists and hands. Conclusion These results suggest that reinnervated muscles can produce sufficient EMG information to control advanced artificial arms. PMID:19211469

Biometrical characteristics and physiological responses to a local cold exposure of the extremities.

PubMed

Savourey, G; Sendowski, I; Bittel, J

1996-01-01

The aim of this study was firstly to describe the physiological responses observed in 19 subjects during immersion of the arm up to the elbow in water at 5 degrees C (5 min) followed by a 10-min recovery and secondly, to correlate the observed physiological responses with biometrical characteristics of the subjects (maximal oxygen uptake, VO2max, percentage fat content of whole body, BF, and arm, forearm and hand skinfold thickness). The results showed that the time courses of changes in forearm and hand skin temperature were different compared to those of finger skin temperatures both during local cooling and during rewarming (P < 0.05). Cardiovascular responses (heart rate, systolic and diastolic blood pressures) and finger skin temperatures were not related to the biometrical characteristics of the subjects. However, at the end of the immersion, decreased hand skin temperature was correlated to VO2max (r = 0.45, P < or = 0.05) whereas decreased forearm skin temperature was correlated both to VO2max (r = 0.44, P < or = 0.05) and to skinfold thickness (r = -0.44, P < or = 0.05) but not to BF. During the beginning of the recovery period only, outside, inside forearm and hand skin temperatures were related to VO2max (r = 0.54, P < or = 0.05; r = 0.66, P < or = 0.01 and r = 0.45, P < or = 0.05, respectively) and all the skinfold thicknesses (r = -0.47 to -0.71, P < or = 0.05). It was concluded that the local skin temperature profiles differed according to the upper limb segment both during cooling and during early rewarming. Moreover, VO2max and upper limb skinfold thickness but not BF did influence the forearm and hand skin temperature changes during cooling and early rewarming but not the finger skin temperature changes and cardiovascular responses.

Cross-Cultural Adaptation of the Disability of Arm, Shoulder, and Hand Questionnaire: Spanish for Puerto Rico Version

ERIC Educational Resources Information Center

Mulero-Portela, Ana L.; Colon-Santaella, Carmen L.; Cruz-Gomez, Cynthia

2009-01-01

The purpose of this study was to perform a cross-cultural adaptation of the Disability of Arm, Shoulder, and Hand (DASH) questionnaire to Spanish for Puerto Rico. Five steps were followed for the cross-cultural adaptation: forward translations into Spanish for Puerto Rico, synthesis of the translations, back translations into English, revision by…

Vocational Rehabilitation of Young Adults with a Disability of One Arm or Hand.

ERIC Educational Resources Information Center

Nijboer, Irene D.; Wevers, Cornelius J.

1993-01-01

A work analysis was conducted to determine whether the job of lathe and milling machine operator is suitable for young adults with one arm or hand. The analysis concluded that it is suitable but adjustments of the workplace may be necessary, such as transporting heavy equipment. The importance of labor research to vocational rehabilitation is…