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Objectives: The aim was to examine exposure-response relations between occupational hand exposures and carpal tunnel syndrome (CTS) and to compare the relation between surgery-treated and non-surgery-treated CTS. The secondary aim was to study sex-specific differences in exposure-response relations., Methods: We conducted a nationwide register-based cohort study of all persons born in Denmark (1945-1994). During follow-up (2010-2013), we identified first-time events of CTS. Occupational hand exposure estimates the year before each follow-up year were obtained by linking individual occupational codes with a job exposure matrix. We used multivariable logistic regression equivalent to discrete survival analysis based on sex and surgery. The excess fraction of cases was calculated., Results: For both sexes, exposure-response relations were found for all occupational hand exposures. Among men, we found OR adj of 3.6 (95% CI 3.2 to 3.8) for hand-related force, 2.9 (95% CI 2.5 to 3.2) for repetitive hand movements, 3.8 (95% CI 2.7 to 5.2) for non-neutral hand posture and 2.5 (95% CI 2.2 to 2.7) for hand-arm vibration in the highest exposure groups. For combined exposure (hand load), OR adj was 3.5 (95% CI 3.1 to 4.0). Slightly higher ORs adj were generally found for surgery-treated CTS compared with non-surgery-treated CTS for both sexes. When comparing sex, somewhat higher ORs adj were found among men. The excess fraction was 42%., Conclusions: Occupational hand exposures carried a 3-5-fold increased risk of CTS with slightly higher risks for surgery-treated compared with non-surgery-treated CTS. Even though CTS occurs more frequently among women, somewhat higher exposure-response relations were found for men compared with women. In the general working population, a substantial fraction of first-time CTS could be related to occupational hand exposures., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Local vibration can induce vascular injuries, one example is the hand-arm vibration syndrome (HAVS) caused by hand-transmitted vibration (HTV). Little is known about the molecular mechanism of HAVS-induced vascular injuries. Herein, the iTRAQ (isobaric tags for relative and absolute quantitation) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics approach was applied to conduct the quantitative proteomic analysis of plasma from specimens with HTV exposure or HAVS diagnosis. Overall, 726 proteins were identified in iTRAQ. 37 proteins upregulated and 43 downregulated in HAVS. Moreover, 37 upregulated and 40 downregulated when comparing severe HAVS and mild HAVS. Among them, Vinculin (VCL) was found to be downregulated in the whole process of HAVS. The concentration of vinculin was further verified by ELISA, and the results suggested that the proteomics data was reliable. Bioinformative analyses were used, and those proteins mainly engaged in specific biological processes like binding, focal adhesion, and integrins. The potential of vinculin application in HAVS diagnosis was validated by the receiver operating characteristic curve.

This study provides an overview of the relationships between exposure to work-related hand-arm vibration and the occurrence of pre-defined disorders of the hands. We searched Medline, Embase, Web of Science, Cochrane Central, and PsycINFO for cross-sectional and longitudinal studies on the association between work-related vibration exposure and the occurrence of hand-arm vibration syndrome (including vibration-induced white finger), Dupuytren's contracture, or hypothenar hammer syndrome. We used a 16-item checklist for assessing the risk of bias. We present results narratively, and we conducted random effects meta-analyses if possible. We included 10 studies with more than 24,381 participants. Our results showed statistically significant associations between the exposure to hand-arm vibrations and the occurrence of the selected disorders, with pooled odds ratios ranging between 1.35 (95% CI: 1.28 to 2.80) and 3.43 (95% CI: 2.10 to 5.59). Considerable between-study heterogeneity was observed. Our analyses show that exposure to vibrating tools at work is associated with an increased risk for the occurrence of selected disorders of the hands. Due to the majority of studies being cross-sectional, no firm conclusion is possible regarding causal relationships between vibration exposure and disorder occurrence. Future research should specifically address whether reducing exposure to hand-held vibrating tools at work reduces the incidence of the disorders of the hands investigated in this systematic review.

Background: Constant use of hand-held vibratory tools may cause health issues, including hand dysfunction, among farmers. Thus, exposure to these vibratory instruments may cause hand-arm vibration syndrome (HAVS)., Objective: The study aimed to measure the prevalence of HAVS and evaluate neurological and vascular symptoms among farmers., Methods: This cross-sectional study included 20 villages in Pakistan and used a three-part questionnaire to collect data from farmers exposed to vibration while farming. The study included demographics, the Health Surveillance Questionnaire, and the Stockholm Workshop Classification Scale. SPSS version 22 was used for the data entry and statistical analysis., Results: 433 (43%) participants had musculoskeletal discomfort and 568 (57%) had hand vibration. Raynaud phenomenon was evident in 430 (43%) participants, whereas carpal tunnel syndrome was found in 218 (22%). Tingling was reported by 255 participants (26%), and numbness was reported by 543 (54%). According to the grading of neurological symptoms, 461 (46%) participants were exposed to vibration but did not experience any symptoms, placing them in stage 0. 185 (18.5%) participants with HAVS with infrequent episodes affecting just the tips of one or more fingers were categorized in stage 01 based on grading of vascular symptoms., Conclusion: HAVS are common among harvesting farmers, with the most noticeable vibrations occurring in the shoulder region. Similarly, most farmers had no vascular symptoms, and most were exposed to vibration but had no neurological symptoms.

Background: hand-arm vibration is one of the typical annoying physical factors. Hand-arm vibration syndrome (HAVS) is a disorder caused by vibrating working tools which vibrate hands beyond the threshold. Long-term HAVS may result in damage to blood vessels, chronic numbness in the fingers, bone injury, and muscular weakness. People are exposed to high-rate noise vibration in a variety of situations, including vessel employment and operating in tiny boats. Moreover, the extant study was conducted to examine manual function disability levels caused by Sailing Speed Vessels (SSV) vibration., Methods: The extant study was quasi-experimental research in which, 52 male sailors in SSVs were chosen as the experimental group, and 27 office personnel were selected as the control group. The demographic factors questionnaire, DASH questionnaire, grip and pinch strength tests, the neurosensory exam, and the skill-dexterity test were all employed in this study. SPSS23 software was used to analyze the data., Results: The findings suggested that the experimental group experienced greater vibration disorder symptoms than the control group. Because the experimental group had a higher score, the individuals experienced poorer circumstances in terms of arm, shoulder, and hand impairment as compared to the control group. The mean grip strength of hands and fingers in two hands of the experimental group was lower than the control group (P < 0.05). There was a statistically significant relationship among grip strengths of both experimental and control groups (P < 0.05). There was a reduction in skill and dexterity of both dominant and non-dominant hands of members in the experimental group. According to the statistical tests, there was no significant association between dominant (P = 0.001) skills and non-dominant (P = 0.010) hands in experimental and control groups. There was not also any significant relationship between skill and dexterity of both hands (P = 0.001) and the dominant hand tweezer test (P = 0.001) in two experimental and control groups. There was a statistically significant association between experimental and control groups in terms of assembly skill and dexterity (P = 0.482)., Conclusion: Individuals who are at risk of vibration experience less physical and sensory function. DASH score, grip strength, skill, and dexterity could predict the reduction in physical function disability., (© 2022. The Author(s).)

Prolonged and intensive vibration exposures during the grinding of handheld workpieces may cause hand-arm vibration syndrome. The objectives of this study are to develop an on-the-hand method for evaluating vibration-reducing (VR) gloves, and to determine whether VR gloves can significantly reduce the vibration exposures. A worker holding and pressing a typical workpiece (golf club head) against a grinding wheel or belt in order to shape the workpiece was simulated, and the input vibration and those on the workpiece and hand-arm system were measured. Ten human subjects participated in the experiment. The results demonstrate that VR gloves significantly reduced the vibrations at the palm, hand dorsum, and wrist. The grinding interface condition and hand feed force did not substantially affect glove effectiveness. The use of gloves slightly increased the workpiece resonant response, but the resonant response did not significantly affect glove effectiveness. This study concluded that the use of VR gloves can help control vibration exposures of workers performing grinding of handheld workpieces., (Published by Elsevier Ltd.)

In 167 men with vibration syndrome (VS), allele and genotype frequencies of HSPA1B (+1267A>G) genetic polymorphism (rs1061581) were studied depending on the type of vibration exposure and on the presence or absence of metabolic syndrome (MetS). The examined subjects were divided into two groups: VS patients (n=80) and VS+MetS patients (n=87). The differences in the lipid profiles between groups were revealed against the background of the lack of distinctions in the age of patients for A/G and G/G genotypes carriers. An increase in A/A (p=0.03) and a decrease in A/G (p=0.04) genotype frequencies in VS patients caused by hand-transmitted vibration in comparison with those in whom the disease was caused by a combination of hand-transmitted and whole-body vibration were found. The shifts in the frequencies of the above genotypes (p=0.01) were similar in patients with both types of vibration exposure in the VS+MetS group in comparison with VS group; the carriage of genotypes with the G allele in VS group exceeded that in VS+MetS group (p=0.01)., (© 2021. Springer Science+Business Media, LLC, part of Springer Nature.)

Objectives: To study the characteristics and the factors influencing the occurrence of the Hand-Arm Vibration Syndrome (HAVS) for a population grinding handheld workpieces in a subtropical environment., Methods: A total of 803 workers grinding handheld workpieces formed the exposure group and 464 workers not exposed to hand-transmitted vibration (HTV) were recruited as the non-exposed group within the same factory in a subtropical climate area. The basic personal information and clinical symptoms reported were collected by trained physicians using a questionnaire and representative measurements were made of the HTV exposure levels and dose., Results: The average HTV exposure dose A(8) was measured as 5.3 ± 2.0 m/s 2 . The proportion of grinders reporting finger blanching was 15.4% while it was 27.5% for finger numbness. Among the non-exposed group, that proportion was 0% and 6.3% respectively. There was a positive association between the vibration exposure duration and the occurrence of finger blanching, finger numbness and finger coldness. Riding a motorcycle to work was also identified as a factor that could contribute to a higher prevalence of finger blanching among the exposed workers, the OR value was found to be 1.75 (1.12, 2.75)., Conclusions: Workers exposed to vibration in a subtropical area can also present evidence of finger blanching in addition to neurological symptoms. The reported rate of HAVS was positively associated with the exposure duration. And the levels of the duration of exposure relative to symptoms of vibration white finger in a subtropical temperate environment exposed to a high-frequency vibration might be deemphasized by the current ISO weighting. Motorcycle transportation to work was identified as a factor that could influence the development of the HAVS among the exposed population of grinders.

Hand-arm vibration syndrome (HAVS) is an irreversible neurodegenerative, vasospastic, and musculoskeletal occupational disease of workers who use powered hand tools. The etiology is poorly understood. Neurological symptoms include numbness, tingling, and pain. This study examines impact hammer vibration-induced injury and recoverability of hair mechanosensory innervation. Rat tails were vibrated 12 min/d for 5 weeks followed by 5 week recovery with synchronous non-vibrated controls. Nerve fibers were PGP9.5 immunostained. Lanceolate complex innervation was compared quantitatively in vibrated vs sham. Vibration peak acceleration magnitudes were characterized by frequency power spectral analysis. Average magnitude (2515 m/s 2 , root mean squared) in kHz frequencies was 109 times that (23 m/s 2 ) in low Hz. Percentage of hairs innervated by lanceolate complexes was 69.1% in 5-week sham and 53.4% in 5-week vibration generating a denervation difference of 15.7% higher in vibration. Hair innervation was 76.9% in 5-weeks recovery sham and 62.0% in 5-week recovery vibration producing a denervation difference 14.9% higher in recovery vibration. Lanceolate number per complex (18.4 ± 0.2) after vibration remained near sham (19.3 ± 0.3), but 44.9% of lanceolate complexes were abnormal in 5 weeks vibrated compared to 18.8% in sham. The largest vibration energies are peak kHz accelerations (approximately 100 000 m/s 2 ) from shock waves. The existing ISO 5349-1 standard excludes kHz vibrations, seriously underestimating vibration injury risk. The present study validates the rat tail, impact hammer vibration as a model for investigating irreversible nerve damage. Persistence of higher denervation difference after 5-week recovery suggests repeated vibration injury destroys the capability of lanceolate nerve endings to regenerate., (© 2020 Peripheral Nerve Society.)

Objective: To investigate whether low molecular organic biomarkers could be identified in blood samples from vibration exposed workers using a metabolomics., Methods: The study population consisted of 38 metalworkers. All participants underwent a standardized medical examination. Blood samples were collected before and after work shift and analyzed with gas chromatography time-of-flight mass spectrometry. Multivariate modeling (orthogonal partial least-squares analysis with discriminant analysis [OPLS-DA]) were used to verify differences in metabolic profiles., Results: Twenty-two study participants reported vascular symptoms judged as vibration-related. The metabolic profile from participants with vibration-induced white fingers (VWF) was distinctly separated from participants without VWF, both before and after vibration exposure., Conclusion: Metabolites that differed between the groups were identified both before and after exposure. Some of these metabolites might be indicators of health effects from exposure to vibrations. This is the first time that a metabolomic approach has been used in workers exposed to vibrations.

Background: Prolonged exposure to hand-arm vibration is associated with a disorder of the vascular, neurological, and musculoskeletal systems of the upper limb known as hand-arm vibration syndrome (HAVS). Currently, the evidence of HAVS in tropical environments is limited., Objectives: To determine the prevalence and severity of HAVS among tyre shop workers in Kelantan, Malaysia., Methods: A cross-sectional study involving 200 tyre shop workers from two districts in Kelantan was performed. Part one data were collected at the field using questionnaire, and hand-arm vibration was measured. Part two involved a set of hand clinical examinations. The workers were divided into high (≥5 m s -2 ) and low/moderate (<5 m s -2 ) exposure group according to their 8-hr time weighted average [A(8)] of vibration exposure. The differences between the two exposure group were then compared., Results: The prevalence of the vascular, neurological, and musculoskeletal symptoms was 12.5% (95% CI 10.16 to 14.84), 37.0% (95% CI 30.31 to 43.69), and 44.5% (95% CI 37.61 to 51.38) respectively. When divided according to their exposure statuses, there was a significant difference in the prevalence of HAVS for all three components of vascular, neurological, and musculoskeletal (22.68% vs 2.91%, 62.89% vs 12.62% and 50.52% and 38.83%) respectively. All the clinical examinations findings also significantly differed between the two groups with the high exposure group having a higher abnormal result., Conclusion: Exposure to high A(8) of vibration exposure was associated with a higher prevalence of all three component of HAVS. There is a need for better control of vibration exposure in Malaysia., (© 2019 The Authors. Journal of Occupational Health published by John Wiley & Sons Australia, Ltd on behalf of The Japan Society for Occupational Health.)

A 56-year-old truck driver with a history of tobacco use presented with acute onset digital ischaemia in the ulnar distribution of his dominant hand, associated with severe pain. Occupational exposures included extensive manual labour and prolonged vibratory stimuli. Workup with Doppler and angiography confirmed the diagnosis of hypothenar hammer syndrome (HHS). After the failure of medical management, he underwent ulnar artery thrombectomy with reconstruction and arterial bypass grafting. His pain improved significantly postsurgically, and he was able to return to a normal routine. This case illustrates the classic presentation, examination, imaging findings and management options of HHS. HHS should be considered in patients with digital ischaemia and associated occupational exposures. Diagnosing the condition appropriately allows for optimal management, aiming at minimising symptoms and maximising quality of life., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: To provide an updated epidemiological validation for a supplementary method for assessing the risk of vascular disorders from hand-transmitted vibration., Methods: The occurrence of vibration-induced white finger (VWF) in the vibration-exposed workers of the Italian cohort of the EU VIBRISKS study was related to measures of daily vibration exposure expressed in terms of r.m.s. acceleration magnitude normalised to an 8-h day, frequency weighted according to either the frequency weighting W h defined in international standard ISO 5349-1:2001 [A h (8) in ms - 2 ] or the hand-arm vascular frequency weighting W p proposed in the ISO technical report (TR) 18570:2017 [A p (8) in ms - 2 ]. To estimate a threshold value for vascular hand-arm vibration risk, the W p -weighted vibration exposure value E p,d (in ms - 1.5 ) was calculated according to the ISO/TR document. The difference in the predictions of VWF between the exposure measures calculated with the frequency weightings W h or W p was investigated by means of logistic modelling., Results: Measures of daily vibration exposure constructed with the frequency weighting W p [A p (8) and E p,d ], which gives more importance to intermediate- and high-frequency vibration, were better predictors of the occurrence of VWF in the vibration-exposed workers than the metric derived from the conventional ISO frequency weighting W h [A h (8)]. There was some epidemiological evidence for a threshold value of E p,d for the onset of VWF in the vibration-exposed workers., Conclusions: Measures of daily vibration exposure evaluated with the vascular weighting W p performed better for the predictions of VWF than those obtained with the frequency weighting W h recommended in ISO 5349-1.

Introduction: Weed control is one of the most important issues in the maintenance sectors of both agriculture and green areas. Small tools are employed for controlling grass and other growths on steep verges and river banks. This leads the operators being exposed to many risks among which vibration is one. The purpose of this study is to measure and evaluate hand-arm vibration and to verify the daily exposure to which workers are often subjected while weeding., Material and Methods: Two cutting heads, a brush knife and a mowing head were compared. Both were mounted on the same cow-horn brush cutter. The vibration total value was expressed as the root-mean-square (rms) of three component values according to the axes X, Y and Z. The signal was frequency weighted using the weighting curve Wh, as described in the ISO 5349-1 (2001) standard. In addition, the daily vibration exposure was calculated and compared with the thresholds set by EU Directive 2002/44/EC (2005)., Results: The obtained results showed that the exposure action value (EAV) of 2.5 ms -2 was exceeded while using both cutting heads. The exposure limit value (ELV) using the brush knife also exceeded 5 ms -2 ., Conclusions: The results highlighted important aspects in terms of exposure values that should be considered with the view of preventing the risk of Hand-Arm Vibration Syndrome (HAVS) to which the operators who frequently use these tools are exposed. Specific measures should therefore be taken to protect the exposed workers.

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.

Workers in a number of different occupational sectors are exposed to workplace vibration on a daily basis. This exposure may arise through the use of powered-hand tools or hand-transmitted vibration (HTV). Workers might also be exposed to whole body vibration (WBV) by driving delivery vehicles, earth moving equipment, or through use of tools that generate vibration at low dominant frequencies and high amplitudes, such as jackhammers. Occupational exposure to vibration has been associated with an increased risk of musculoskeletal pain in the back, neck, hands, shoulders, and hips. Occupational exposure may also contribute to the development of peripheral and cardiovascular disorders and gastrointestinal problems. In addition, there are more recent data suggesting that occupational exposure to vibration may enhance the risk of developing certain cancers. The aim of this review is to provide an assessment of the occupations where exposure to vibration is most prevalent, and a description of the adverse health effects associated with occupational exposure to vibration. This review will examine (1) various experimental methods used to measure and describe the characteristics of vibration generated by various tools and vehicles, (2) the etiology of vibration-induced disorders, and (3) how these data were employed to assess and improve intervention strategies and equipment that reduces the transmission of vibration to the body. Finally, there is a discussion of the research gaps that need to be investigated to further reduction in the incidence of vibration-induced illnesses and injuries.

Objectives: In this study, the daily exposure action values (EAV) and the daily exposure limit values (ELV) for hand-transmitted vibration (HTV) and whole-body vibration (WBV), established by the EU Directive 2002/44/EC and the Italian Decree 81/2008, and expressed in terms of 8-hr frequency weighted r.m.s. acceleration magnitude, are discussed upon consideration of the findings of experimental and epidemiological studies., Methods: There is some epidemiological support for the EAV A(8) of 2.5 ms-2 r.m.s. and the ELV A(8) of 5 ms-2 r.m.s. for HTV, at least for the vascular component (secondary Raynaud's phenomenon) of the hand-arm vibration syndrome., Results: There is some experimental evidence for the EAV A(8) of 0.5 ms-2 r.m.s. for WBV, while there is neither biodynamic nor epidemiological validation for the ELV A(8) of 1.15 ms-2 r.m.s. for WBV, this latter lowered to 1 ms-2 r.m.s. in the Italian legislation., Competing Interests: The authors of this article have no conflict of interests to disclose., (Copyright© by Aracne Editrice, Roma, Italy.)

Objective: 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., Sources of Information: 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., Main Message: 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., Conclusion: 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.)

Objectives: 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., Methods: 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., Results: 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)., Conclusions: 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., Competing Interests: The authors declare that they have no conflict of interest.

Objective: To investigate the exposure-response relationships between alternative frequency weightings of hand-transmitted vibration (HTV) and neck and upper limb musculoskeletal disorders (MSDs) in a cohort of HTV workers., Methods: In a three-year longitudinal study, the occurrence of neck and upper limb MSDs was investigated in 249 HTV workers and 138 control men. In the HTV workers, MSDs were related to measures of daily vibration exposure expressed in terms of 8-h energy-equivalent frequency-weighted acceleration magnitude [A(8)]. To calculate A(8), the acceleration magnitudes of vibration were weighted by means of four alternative frequency weightings of HTV. The associations between MSDs, individual characteristics, physical work load other than vibration, and psychological strain were also investigated., Results: The occurrence of upper limb MSDs was greater in the HTV workers than in the controls. After adjustment for potential confounders, the occurrence of elbow/forearm and wrist/hand MSDs increased with the increase in vibration exposure. A measure of model selection did not reveal any substantial difference in the performance of the alternative frequency weightings of HTV for the prediction of neck and upper limb MSDs. In the study population, age, hard physical work load, and poor psychological well-being were associated with both neck and upper limb MSDs., Conclusions: In this study, there was evidence for significant exposure-response relationships between HTV exposure and MSDs in the distal sites of the upper limbs. There were no differences in the prediction of neck and upper limb MSDs between measures of daily vibration exposure calculated with alternative frequency weightings of acceleration magnitude.

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.)

Objectives: 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., Methods: 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., Results: 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., Conclusions: 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.

Purpose: 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., Methods: 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., Results: 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., Conclusions: Differences in vasoconstriction between subjects and between locations are consistent with the Pacinian channel mediating both absolute thresholds and vibration-induced vasoconstriction.

Background: In hospitals, the use of vibrating tools, such as oscillating saws to cut plaster, can expose the staff to hand-arm vibrations., Objectives: The aim of the study was to assess the exposure of workers to vibrations in the plaster room and then  identify the most appropriate  intervention for  prevention and protection to be implemented in order to minimize  exposure and  protect  workers' health, considering different individual hyper-susceptibility conditions., Methods: Four different models of plaster saws were examined for the evaluation.  Various measurements were made in normal working conditions of the operators., Results and Conclusions: The values of acceleration and noise detected on the instruments  were  in line with those reported in the literature. The preventive measure adopted (replacing plaster saws currently used in the hospital with similar ones with lower vibration emission) was an adequate means of protection. Health surveillance activities  recorded a higher level of wellbeing, both environmentally and individually and, specifically, an increased protection level for the hyper-susceptibility conditions observed during health checks of exposed personnel  which will be monitored regularly by the Occupational Health Service.

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.

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.)

The article presents results of longstanding studies on influence of occupational physical factors on workers health. Experimental and nature studies helped to justify basic concepts of sensory conflict theory, a trigger of occupational disease formation. Patients having occupational disease present disorders of cortex-subcortex relationships on diencephal level, central and peripheral regulatory mechanisms, central sensory mechanisms participation in pathologic processes development, changes in vegetative regulation on cerebral level, demyelination and axon demyelination changes in peripheral nerves of upper and lower limbs. Findings are also changes in central nervous, peripheral nervous systems, endocrine, immune systems, severe emotional negative strain and high level of nervous system excitation, perivascular edema in brain cortex of experimental animals. Based on key principles of the theory, the authors specified and tested new methods of treatment and prevention of occupational diseases caused by physical factors, aimed to unblock the sensory conflict.

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.

Objective: 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)., Methodology: 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., Results: 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., Discussion: 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.

Background: Hand-arm vibration exposure may cause hand-arm vibration syndrome (HAVS) including sensorineural disturbances., Aims: To investigate which factors had the strongest impact on work ability in vibration-exposed workers., Methods: 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., Results: 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)., Conclusions: 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.)

Objective: 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., Methods: 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., Results: 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., Conclusion: 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.

A frequently encountered exposure profile for hand-arm vibration in contemporary occupational setting comprises workers with a long history of intermittent exposure but without detectable signs of hand-arm vibration syndrome (HAVS). Yet, most of the published studies deal with developed HAVS cases, rarely discussing the biological processes that may be involved in degradation of manual dexterity and grip strength when it can be most beneficial - during the asymptomatic stage. In the present paper, a group of 31 male asymptomatic vibration-exposed workers (according to the Stockholm Workshop Scale) were compared against 30 male controls. They were tested using dynamometry and dexterimetry (modelling coarse and fine manual performance respectively) and cold provocation was done to detect possible differences in manual performance drop on these tests. The results showed reduced manual dexterity but no significant degradation in hand grip strength in the exposed subjects. This suggests that intermittent exposure profile and small cumulative vibration dose could only lead to a measurable deficit in manual dexterity but not hand grip strength even at non-negligible A(8) levels and long term exposures.

Objective: 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)., Methods: 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., Results: 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., Conclusion: 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.

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.

Introduction: Woodcutters' working conditions are difficult due to the presence of numerous occupational hazards. Petrol-fuelled chain saws commonly used in forestry produce vibration, which may lead to the development of non-specific disorders in the upper extremities of the chain saw operator, referred to as hand-arm vibration syndrome (HAVS). The magnitude of coupling forces exerted on a vibrating tool handle may affect the severity of HAVS and hand-wrist cumulative trauma disorders. The aim of the presented study was to measure coupling forces exerted by fellers on various chain saws and to find correlation between force magnitude and type of tool used., Material and Methods: Coupling forces applied by workers on different types of chain saws were measured by means of a hydro-electronic force meter. All measurements were carried out during the harvesting of wood in real work conditions., Results: Mean force applied by forestry workers on their tools was 44.2 N. Coupling forces registered during cutting wood with small universal chain saws were larger than forces exerted on models characterized by higher power profile. Forces applied on comparable tools produced by various manufacturers also differed., Conclusions: The relationship between coupling forces and power of the chain saw should lead to ergonomic improvements of the tool and vibration-reducing devices. These results can also be used as a recommendation for fellers in a range of using proper machines for different types of cut or types of wood. They may also be applicable to develop more effective methods for assessing vibration exposure risks among woodcutters.

The study was aimed to reveal efficiency of extracorporeal shock-wave therapy in complex treatment of vibration disease patients. Examination covered 92 patients with varying severity of vibration disease, 58 of which received extracorporeal shock-wave therapy with Piezo Wave device produced by Richard Wolf in addition to traditional treatment. The treatment efficiency was evaluated through its influence on intensity and regression of pain syndrome. Comparative analysis showed that extracorporeal shockwave therapy in the treatment complex considerably increases efficiency and leads to earlier and more stable regression of pain in distal parts of hands. Two variants of chronic pain response to extracorporeal shock-wave therapy were revealed. Marked analgetic potential, good tolerance and stability of the results obtained enable to recommend extracorporeal shock-wave therapy in rehabilitation complex for vibration disease patients.

The authors studied serum levels of neurotrophic factors (brain-derived neurotrophic factor BDNF and ciliary neurotrophic factor CNTF) in workers exposed to vibration (workers with long length of service and without health disorders caused by vibration, patients with occupational limbs polyneuropathy, and vibration disease patients). Findings are that occupational vibration induces increased BDNF and CNTF serum levels in all groups examined. Increased levels of neurotrophic factors at early stages of pathologic process indicate their protective action, action of compensatory protective mechanisms. However, high levels of BDNF and CNTF in vibration disease may point to neurodestructive processes in nervous system.

Background: 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., Methods: 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., Results: 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., Conclusions: 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.

Purpose: The purpose of this study was to describe normative data for the neuromuscular assessments of the hand-arm vibration syndrome (HAVS) in Korean., Methods: 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., Results: 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., Conclusions: The current data can be used to evaluate HAVS in Korean male workers. Age is an important factor for VPT.

History and Admission Findings: A 34-year-old female stonemason was referred for expert opinion. The question at issue was, whether she suffered from vibration-induced white finger disease. She was exposed to high-frequency hand-arm vibrations for many years. She reported white finger attacks at the long fingers, which were associated with cold weather. Until this point, physical findings were normal., Investigations: The cold water provocation test showed a slight delay of the rewarming for the long fingers of the right hand. The nailfold capillary microscopy was normal., Diagnosis and Course: The slight Raynaud's phenomenon was recognized as an occupational disease with a diagnosis of vibration-induced white finger disease. About three years later, the symptoms of the Raynaud's phenomenon had deteriorated, although the patient had finished working with vibrating tools. The cold water provocation test confirmed the deterioration. At this time, the patient had inflamed swellings of some joints caused by rheumatoid arthritis., Conclusion: The differential diagnosis of a Raynaud's phenomenon should include occupational causes. Occupational history is diagnostically indicative. If an occupational disease is assumed, a report must be filed. With respect to German social law, the deterioration of the Raynaud's phenomenon was caused by the rheumatoid arthritis, which is regarded as independent from the job., (© Georg Thieme Verlag KG Stuttgart · New York.)

Hand-Arm Vibration Syndrome (HAVS) is caused by hand-transmitted vibration in industrial workers. Current ISO guidelines (ISO 5349) might underestimate vascular injury associated with range of vibration frequencies near resonance. A rat-tail model was used to investigate the effects of higher frequencies >100 Hz on early vascular damage. 13 Male Sprague-Dawley rats (250 ± 15 gm) were used. Rat-tails were vibrated at 125 Hz and 250 Hz (49 m/s(2)) for 1D, 5D and 10D; D=days (4 h/day). Structural damage of the ventral artery was quantified by vacuole count using Toluidine blue staining whereas biochemical changes were assessed by nitrotyrosine (NT) staining. The results were analyzed using one-way repeated measures mixed-model ANOVA at p<0.05 level of significance. The structural damage increased at 125 Hz causing significant number of vacuoles (40.62 ± 9.8) compared to control group (8.36 ± 2.49) and reduced at 250 Hz (12.33 ± 2.98) compared to control group (8.36 ± 2.49). However, the biochemical alterations (NT-signal) increased significantly for 125 Hz (143.35 ± 5.8 gray scale value, GSV) and for 250 Hz (155.8 ± 7.35 GSV) compared to the control group (101.7 ± 4.18 GSV). Our results demonstrate that vascular damage in the form of structural and bio chemical disruption is significant at 125 Hz and 250 Hz. Hence the current ISO guidelines might underestimate vascular damage at frequencies>100 Hz.

Background: Hand-arm vibration syndrome (HAVS) is a relatively common occupational disease, especially in certain industrial sectors. Affected workers in many jurisdictions are eligible for compensation, but little is known about the behaviour and characteristics of workers seeking compensation for HAVS., Aims: To characterize the workers seeking compensation for HAVS based on demographics, occupation and disease characteristics., Methods: All accepted claims for HAVS from 1999 to 2008 in British Columbia were reviewed., Results: The average claimant was 50 years old and had worked 25 years. The average latency period for developing HAVS symptoms was 18 years, and half the number of symptomatic workers waited 5 years or more before filing a claim. Loggers developed symptoms, on average, after 17 years of exposure, significantly earlier than mechanics, who developed symptoms after 24 years of work. Loggers waited longer than mechanics to file claims, with a median delay of 6 years, compared with 3 years for mechanics. The majority of HAVS claims involved severer vascular and sensorineural symptoms., Conclusions: Claimants commonly delay filing compensation claims and this may result in severer symptoms when the claims are filed. Further study is required to explain this delay.

Prolonged exposure to hand-arm vibration (HAV) generated by chainsaws can cause HAV syndrome, i.e., disorders in the upper extremities of forestry workers. Progress of HAV syndrome depends on the intensity of mechanical vibration transmitted throughout the body, which is directly proportional to coupling forces applied by the woodcutter to a vibrating tool. This study aimed to establish a method of measuring coupling forces exerted by chainsaw workers in real working conditions. Coupling forces exerted by workers with their right and left hands were measured with a hydro-electronic force meter. Wood hardness, the type of chainsaw and the kind of forest operation, i.e., felling, cross-cutting or limbing, were considered.

An analysis has been performed to derive a frequency weighting for the development of vibration-induced white finger (VWF). It employs a model to compare health risks for pairs of population groups that are selected to have similar health outcomes from operating power tools or machines with markedly different acceleration spectra (rock drills, chain saws, pavement breakers and motorcycles). The model defines the Relative Risk, RR(f(trial)), which is constructed from the ratio of daily exposures and includes a trial frequency weighting that is applied to the acceleration spectra. The trial frequency weighting consists of a frequency-independent primary frequency range, and subordinate frequency ranges in which the response to vibration diminishes, with cut-off frequencies that are changed to influence the magnitude of RR(f(trial)). The frequency weighting so derived when RR(f(trial)) = 1 is similar to those obtained by other methods (W(hf), W(hT)). It consists of a frequency independent range from about 25 Hz to 500 Hz (-3 dB frequencies), with an amplitude cut-off rate of 12 dB/octave below 25 Hz and above 500 Hz. The range is compatible with studies of vasoconstriction in persons with VWF. The results provide further evidence that the ISO frequency weighting may be inappropriate for assessing the risk of developing VWF.

Occupational exposure to vibration through the use of power- and pneumatic hand-tools results in cold-induced vasospasms, finger blanching, and alterations in sensorineural function. Collectively, these symptoms are referred to as hand-arm vibration syndrome (HAVS). Currently the International Standards Organization (ISO) standard ISO 5349-1 contains a frequency-weighting curve to help workers and employers predict the risk of developing HAVS with exposure to vibration of different frequencies. However, recent epidemiological and experimental evidence suggests that this curve under-represents the risk of injuries to the hands and fingers induced by exposure to vibration at higher frequencies (>100 Hz). To improve the curve, better exposure-response data need to be collected. The goal of this review is to summarize the results of animal and computational modeling studies that have examined the frequency-dependent effects of vibration, and discuss where additional research would be beneficial to fill these research gaps.

This invited paper reviews experimental studies of the frequency-dependence of absolute thresholds for the perception of vibration, equivalent comfort contours, temporary changes in sensation caused by vibration, and reductions in finger blood flow caused by hand-transmitted vibration. Absolute thresholds depend on the contact conditions but for a typical hand grip the thresholds show greatest sensitivity to acceleration around 125 Hz. The frequency-dependence of discomfort caused by hand-transmitted vibration depends on vibration magnitude: similar to absolute thresholds at low magnitudes, but the discomfort at higher magnitudes is similar when the vibration velocity is similar (at frequencies between about 16 and 400 Hz). Hand-transmitted vibration induces temporary elevations in vibrotactile thresholds that reflect the sensory mechanisms excited by the vibration and are therefore highly dependent on the frequency of vibration. Hand-transmitted vibration reduces finger blood flow during and after exposure; when the vibration velocity is similar at all frequencies there is more vasoconstriction at frequencies greater than 63 Hz than at lower frequencies. A single frequency weighting cannot provide a good indication of how all effects of hand-transmitted vibration depend on vibration frequency. Furthermore, a single frequency weighting provides only an approximate indication of any single response, because many factors influence the frequency-dependence of responses to hand-transmitted vibration, including the magnitude of vibration, contact conditions, and individual differences. Although the frequency weighting in current standards extends from 8 to 1,000 Hz, frequencies greater than 400 Hz rarely increase the weighted value on tools and there is currently little psychophysical or physiological evidence of their effects.

Exposure to hand-transmitted vibration is usually assessed according to International Standard ISO 5349-1:2001 using the frequency weighting W(h). This paper compares eight frequency weightings that might be used to supplement or replace W(h). The comparison is based on a data from two databases, one containing over 7200 measured hand-arm vibration (HAV) spectra from a wide range of industrial machines the other recording exposure history and injury for workers referred to the Health and Safety Laboratory. Acceleration spectra from the machinery database are analysed to give weighted values for the alternative frequency weightings. These weighted values are compared and then used to estimate a set of alternative lifetime vibration dose values for subjects in the referral database. Statistical comparison of these lifetime dose values against assessments of hand-arm vibration syndrome (HAVS) and sensorineural HAVS prevalence suggests that values based the two weightings W(h) and W(h50lp) (the W(h) weighing low-pass filtered at 50 Hz) provide the strongest indicators for developing these injuries. For vascular HAVS there was no clear evidence to advocate any individual frequency weighting. For all injury categories the strongest relationships were for the first power of acceleration magnitude.

The objective of this study is to propose a theory on the biodynamic frequency weighting for studying hand-transmitted vibration exposures and vibration-induced effects. We hypothesize that the development of a vibration effect is the result of two consecutive but synergistic processes: biodynamic responses to input vibration and biological responses to the biomechanical stimuli resulting from the biodynamic responses. Hence, we further hypothesize that the frequency-dependency (W) of the effect generally includes two components: a biodynamic frequency weighting (W1) and a biological frequency weighting (W2), or W=W1• W2. These hypotheses are consistent with the stress and strain analysis theory and methods widely used in structural dynamics and biomechanics. The factorization may make it easier to study the complex frequency-dependency using different approaches: the biodynamic frequency weighting depends on the passive physical response of the system to vibration, and it can thus be determined by examining the biodynamic response of the system using various engineering methods; on the other hand, the biological frequency weighting depends on the biological mechanisms of the effects, and it can be investigated by studying the psychophysical, physiological, and pathological responses. To help test these hypotheses, this study reviewed and further developed methods to derive the finger biodynamic frequency weighting. As a result, preliminary finger biodynamic frequency weightings are proposed. The implications of the proposed theory and the preliminary biodynamic frequency weightings are also discussed.

Background: 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., Material and Methods: 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., Results: 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)., Conclusions: 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.