Neurophysiological findings in vibration-exposed male workers

Fractionated nerve conduction, vibrotactile sense, and temperature threshol ds were studied in 73 symptomatic vibration-exposed male workers. Three sym ptomatic groups were distinguished: patients with isolated sensorineural sy mptoms; with isolated vasospastic problems; and with both. Clinical carpal tunnel syndrome occurred in 14 patients and abnormal cold intolerance ( wit hout blanching of the fingers) in 23. In the group as a whole, nerve conduc tion studies were abnormal in the median nerve but not in the ulnar nerve a nd vibration perception and temperature thresholds were impaired. Of the th ree symptomatic groups, patients with isolated sensorineural symptoms diffe red from controls. No differences mere seen between patients with and witho ut clinical carpal tunnel syndrome, With severe sensorineural symptoms the vibration perception thresholds, but not the values of the nerve conduction studies, were further impaired. The results indicated two injuries that ar e easily confused: one at receptor level in the fingertips and one in the c arpal tunnel. Careful clinical assessment, neurophysiological testing, and examination of vibrotactile sense are required before carpal tunnel release should be considered in these patients.