Vibrotactile sense in the hand-arm vibration syndrome

The purpose of this study was to investigate disturbances of the vibrotactile sense and their relation to clinical symptoms and findings among male symptomatic workers suffering from the hand-arm vibration syndrome.

Ninety-six such patients were interviewed and given a clinical and tactilometric examination. The symptoms were classified according to the Stockholm Workshop Scale. A sensibility index was used to quantify vibrotactile sense in the tactilogram.

An abnormal sensibility index (<0.8) was recorded for 57.3% of the patients (mean of 4 fingers), at least 1 finger being abnormal in 72.9% of the patients. The sensibility index did not statistically differ between the patients suffering from sensorineural symptoms and those with vibration white finger. The stages of sensorineural symptoms, according to the Stockholm Workshop Scale, corresponded with the sensibility index, whereas the stages of vibration white finger did not. There were significant differences in the sensibility index between the fingers, between the right and left hands, and between the fingers innervated by the ulnar and median nerves. Bilateral symptoms and cold intolerance were associated with considerable impairment of the vibrotactile sense. Clinical median nerve involvement in the carpal tunnel was not reflected by the sensibility index.

There is a considerable degree of neural involvement in all symptomatic vibration-exposed patients irrespective of symptoms. As symptoms progress, the severity of sensorineural symptoms, but not of vibration white finger, is reflected by the sensibility index. Cold intolerance is strongly related to nervous involvement and should be noted in the patient history. Tactilometry should be performed on 1 median and 1 ulnar nerve-innervated finger of both hands, as an examination of 1 finger alone may be misleading.