Hand-arm vibration syndrome in South African gold miners. (1/53)

BACKGROUND: 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. AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.  (+info)

Cold-provocation testing for the vascular component of hand-arm vibration syndrome in health surveillance. (2/53)

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.  (+info)

Nerve conduction studies and current perception thresholds in workers assessed for hand-arm vibration syndrome. (3/53)

BACKGROUND: Workers exposed to hand-arm vibration are at risk of developing the neurological abnormalities of hand-arm vibration syndrome (HAVS). The Stockholm classification of the neurological component of HAVS is based on history and physical examination. There is a need to determine the association between neurological tests and the Stockholm scale. AIMS: The main objective of this study was to compare the Stockholm neurological scale and the results of current perception threshold (CPT) tests and nerve conduction studies (NCS). METHODS: Detailed physical examinations were done on 162 subjects referred for HAVS assessment at a specialist occupational health clinic. All subjects had NCS and measurement of CPT. The Stockholm neurological classification was carried out blinded to the results of these neurological tests and compared to the test results. RESULTS: The nerve conduction results indicated that median and ulnar neuropathies proximal to the hand are common in workers being assessed for HAVS. Digital sensory neuropathy was found in only one worker. Neither the nerve conduction results nor the current perception results had a strong association with the Stockholm neurological scale. Exposure to vibration in total hours was the main variable associated with the Stockholm neurological scale [right hand: OR 1.30, 95% CI (1.10-1.54); left hand: OR 1.18, 95% CI (1.0-1.39)]. CONCLUSION: Workers being assessed for HAVS should have nerve conduction testing to detect neuropathies proximal to the hand. Quantitative sensory tests such as current perception measurement are insufficient for diagnostic purposes but may have a role in screening workers exposed to vibration.  (+info)

Laser Doppler imaging of skin blood flow for assessing peripheral vascular impairment in hand-arm vibration syndrome. (4/53)

The objective of this study was to evaluate the usefulness of laser Doppler imaging (LDPI) of the skin blood flow for assessing peripheral vascular impairment in the hand-arm vibration syndrome (HAVS). The subjects were 46 male patients with HAVS, aged 50 to 69 yr, and 31 healthy male volunteers of similar age as controls. A cold provocation test was carried out by immersing a subject's hand on his more severely affected side into cold water at a temperature of 10 degrees C for 10 min. Repeated image scanning of skin blood flow of the index, middle, and ring fingers was performed every 2 min before, during, and after the cold water immersion using a PMI-II laser Doppler perfusion imager. The mean blood perfusion values in the distal phalanx area of the fingers were calculated on each image. The patients suffering from vibration-induced white finger (VWF, n=20) demonstrated significantly lower skin blood perfusion at each interval of the test as compared with those without VWF (n=26) and the controls (p<0.01, ANOVA). The blood perfusions in the HAVS patients were associated with the severity of the symptoms as classified by the Stockholm Workshop scale for vascular staging. When a subject was considered to be positive if any of the tested fingers showing a decreased blood perfusion and/or a delayed recovery pattern, the sensitivity was 80.0%, and the specificity was 84.6% and 93.5% for patients without VWF and the controls, respectively. These results suggest that the LDPI technique could provide detailed and accurate information that may help detect the existence of impaired vascular regulation to cold exposure in the fingers of workers exposed to hand-transmitted vibration.  (+info)

Assessment of the hand-arm vibration syndrome: thermometry, plethysmography and the Stockholm Workshop Scale. (5/53)

BACKGROUND: The Stockholm Workshop Scale (SWS) provides a staging scheme for hand-arm vibration syndrome (HAVS) based on subjective history. Cold provocation finger thermometry and plethysmography are commonly used objective tests for the vascular component of HAVS. AIM: To examine the correlation between the cold provocation tests and SWS vascular stage. A secondary goal was to evaluate the correlation between cold provocation finger plethysmography and thermometry testing. METHODS: Patients investigated for HAVS at St Michael's Hospital, Toronto, Ontario, were subjected to the same protocol including a questionnaire, clinical assessment and objective testing. Spearman correlation coefficients were calculated for the vascular tests with the SWS and for the vascular tests themselves. Logistic regression models controlled for age, smoking, use of vasoactive medications and time since last vibration exposure. RESULTS: One hundred and thirty-nine patients investigated for HAVS consented to participate in the study. The correlation coefficients for plethysmography (rho = 0.14) and thermometry (rho = 0.18) with the SWS were not statistically significant. Plethysmography and thermometry results were significantly correlated (rho = 0.47, P < 0.001). Logistic regression showed plethysmography and thermometry to weakly predict SWS vascular stage (OR 1.5 and 1.3, respectively). None of the potential confounders had a significant effect in the models. CONCLUSION: The results of plethysmography and thermometry did not significantly correlate with SWS vascular stage in this study. The objective tests did correlate with each other, suggesting that they are reliable measures of similar phenomena likely related to underlying vascular pathology.  (+info)

Diagnosing soft tissue rheumatic disorders of the upper limb in epidemiological studies of vibration-exposed populations. (6/53)

OBJECTIVES: To investigate approaches adopted to diagnose soft tissue rheumatic disorders of the upper limb (ULDs) in vibration-exposed populations and in other settings, and to compare their methodological qualities. METHODS: Systematic searches were made of the Medline, Embase, and CINAHL electronic bibliographic databases, and of various supplementary sources (textbooks, reviews, conference and workshop proceedings, personal files). For vibration-exposed populations, qualifying papers were scored in terms of the provenance of their measuring instruments (adequacy of documentation, standardisation, reliability, criterion-related and content validity). Similar criteria were applied to general proposals for whole diagnostic schemes, and evidence was collated on the test-retest reliability of symptom histories and clinical signs. RESULTS: In total, 23 relevant reports were identified concerning vibration-exposed populations--21 involving symptoms and 9 involving examination/diagnosis. Most of the instruments employed scored poorly in terms of methodological quality. The search also identified, from the wider literature, more than a dozen schemes directed at classifying ULDs, and 18 studies of test-retest reliability of symptoms and physical signs in the upper limb. Findings support the use of the standardised Nordic questionnaire for symptom inquiry and suggest that a range of physical signs can be elicited with reasonable between-observer agreement. Four classification schemes rated well in terms of content validity. One of these had excellent documentation, and one had been tested for repeatability, agreement with an external reference standard, and utility in distinguishing groups that differed in disability, prognosis and associated risk factors. CONCLUSIONS: Hitherto, most studies of ULDs in vibration-exposed populations have used custom-specified diagnostic methods, poorly documented, and non-stringent in terms of standardisation and supporting evidence of reliability and/or validity. The broader literature contains several question sets and procedures that improve upon this, and offer scope in vibration-exposed populations to diagnose ULDs more systematically.  (+info)

An evaluation of impact wrench vibration emissions and test methods. (7/53)

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Cold haemagglutinin disease misdiagnosed as hand-arm vibration syndrome. (8/53)

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