EQUAL VIBROTACTILE SENSE THRESHOLDS OF THE FINGERS AND ITS DIAGNOSTIC-SIGNIFICANCE FOR HAND-ARM VIBRATION SYNDROME

The vibrotactile sense thresholds (VSTs) of the middle fingers of 60 h ealthy persons and 97 patients with Hand-Arm Vibration Syndrome (HAVS) or subclinical HAVS were measured quantitatively. Intermittent vibrat ory irritations were adopted, with vibration stimulus frequencies at 8 , 16, 31.5, 63, 125, 250, and 500 Hz. The equal VST contours of the fi ngers were mapped. Results showed that the VSTs of the normal group we re not correlated with sex or handedness. From 8 Hz to 250 Hz the equa l VST contours of the normal group were relatively flat; at more than 250 Hz the contours began an abrupt ascent. The VST values had a logar ithmic rising tendency with the increasing age of subjects. In the equ al VST contours the frequency of the most sensitive threshold value wa s 125 Hz in the normal group and 8 Hz in the HAVS group. The patients' VST values were higher than that of the healthy persons. The vibrotac tilegram showed that the VST values of the patient groups first shifte d at high frequencies and VST loss displayed a ''V''-type hollow at 12 5 Hz and 250 Hz. The quantitative test method of VST was a valuable au xiliary detection method for HAVS. The ''V''-type hollow of VST was an early clinical manifestation of HAVS.