Relationship between thresholds detection of vibratory sensation and sensory nerve electrophysiology

Forty-five healthy subjects were investigated using quantitative electrophysiological techniques and vibration thresholds determination. The latencies, durations and amplitudes of sensory action potentials and the sensory conduction velocity were measured in the ulnar nerves. Vibratory sensation thresholds determination were made by an electromagnetic vibrator at the hypothenar eminences, using the frequency of 30 and 250 Hz. The results and their inter-relationships lead to conclusion that the detection thresholds of mechanical sinusoids delivered to the glabrous skin of the human hand are significantly related to the sensory conduction velocity of the nerve innervating the corresponding region of the hand. This was true for the detection of sinusoids of frequency of 250 Hz, i.e. frequency eliciting the sense of diffuse vibrations, and for the detection of sinusoids of frequency of 30 Hz evoking 'flutter' sensation.