Follow-up study of patients with vibration syndrome in Japan.

This study was performed on 187 patients with vibration syndrome treated and followed for more than five years in 10 hospitals in Japan. The subjects had disturbances of circulation and sensation in their fingers and of joint movements in their upper extremities. Most of the patients received treatment combining physical and drug therapy. Data were analyzed to determine the effective treatment period for improving the disturbances. The blanching attack Raynaud's phenomenon) and abnormal cold and tingling sensations in the fingers were significantly improved only during the first two years of treatment. A temperature test and plethysmography suggested improvement in finger circulation only during the first three years and one year of treatment, respectively. Spontaneous numbness and pain in the fingers did not improve. The pin-prick and vibratory sensations showed recovery only during the first three and two years of treatment, respectively. Lowered conduction velocities of the ulnar and median nerves improved only during the first year. Limited movements in the wrist and elbow joints did not improve at all despite long-term treatment. Similar results were seen in an overall evaluation of the data. It was concluded that there is a limitation in the treatment of disturbances related to the vibration syndrome.