Assessing the severity of the hand‐arm vibration syndrome by vibrotactile perception

Recent epidemiological studies of workers exposed to vibration suggest that the neurological, vascular, and musculo‐skeletal disturbances in the hand‐arm system develop independently, with the neurological symptoms reported first. A conservative measure of the severity of the syndrome may thus be derived from the degree of numbness and loss of fine touch, which present evidence suggests is due to mechano‐receptor dysfunction. Recent electrophysiological studies on primates, including man, reveal that not all receptor groups are involved in fine touch (i.e., Pacinian corpuscles). However, current medical practice for assessing the severity of the syndrome: (1) does not attempt to separate the response of different mechano‐receptor groups in vibro‐tactile measurements, and usually records the threshold of Pacinian corpuscles, and (2) is largely based on an evaluation of the vascular component. In view of the new evidence, it is hardly surprising that clinical tests of vibro‐tactile perception as a diagnostic tool have produced contradictory results. An improved method of measurement coupled with a revised medical scheme for diagnosing the neurological component will be discussed.