Hand-arm vibration syndrome; Consequences for hand function and quality of life

Abstract: Workers exposed to hand-held vibrating machines may risk developing a hand-arm vibration syndrome (HAVS), a condition which can cause chronic impairment and disability. The aims of this thesis were 1) to obtain deeper insight and further knowledge of HAVS and the consequences for hand function, and aspects of quality of life (QoL); 2) to investigate the usefulness of clinical assessments in diagnosing HAVS; 3) to evaluate a treatment method for patients with severe cold intolerance. The thesis is based on five papers and a total of 131 vibration exposed workers. A number of questions on hand symptoms, standardised tests of hand function and questionnaires were included. Results: 1) The most common hand symptoms were cold intolerance, numbness and pain. Sensory functions were more disturbed than motor functions in clinical assessments. Working outdoors in cold weather, using vibrating machines, opening lids and packages, writing, lifting and carrying objects appeared more difficult than other activities. Workers with HAVS described lower QoL here expressed as less subjective well-being, more symptoms of ill-health and ADL difficulties than workers without symptoms. 2) Cold intolerance and pain showed a high agreement with the Stockholm Workshop Scales (SWS), the gold standard in diagnosing HAVS. Three out of ten objective tests of hand function, assessing perception of vibration, perception of touch/pressure, and dexterity showed a moderate agreement with SWS. Thus, corresponding defined objective tests of hand function (Tactilometry, Semmes-Weinstein monofilaments, and Purdue pegboard test) combined with questions on cold intolerance and pain, together with the SWS can be helpful for diagnosing HAVS. 3) Behavioural treatment of cold intolerance was not effective in workers with HAVS although digital skin temperature increased after treatment. The results indicated that the subjective assessment of cold intolerance did not correlate with the objective assessment of digital skin temperature. The findings highlight the lack of knowledge of the nature and pathophysiology of cold intolerance. Conclusion: 1) HAVS can result in impaired hand function and lower QoL 2) Specific tests of hand function and questions of hand symptoms can be useful for detecting a vibration injury. 3) Since no treatment of HAVS has proved effective, prophylactic measures should be further highlighted.