MEDIAN NERVE SENSORY RESPONSES EVOKED BY TACTILE STIMULATION OF THE FINGER PROXIMAL AND DISTAL PHALANX IN NORMAL SUBJECTS

We compared the characteristics of near-nerve recorded sensory potenti als elicited in response to electrical stimulation of digital nerves v ersus tactile stimulation of the digital skin in 17 healthy subjects w ith a mean age of 26 years. We also calculated the density of Meissner 's corpuscles in the distal and proximal phalanx of digit III of 6 mal es who had suffered a violent death, but were free from diseases of th e peripheral nerve system. Responses to tactile stimulation had a long er latency and lower amplitude than responses to electrical stimulatio n. Unlike electrically elicited responses, responses to tactile stimul ation, which consisted of six or seven main spike components plus seve ral minor components, were similar in recordings from the wrist and el bow. However, with proximal stimulation the electrically evoked respon ses were more compact and had a higher amplitude and area, whereas the tactile evoked potential became significantly reduced in maximum ampl itude and cumulative area. The differences in sensory conduction betwe en distal and proximal could reflect activation of a larger number of nerve fibers when electrical stimuli are used and a smaller amount of mechanoreceptors when tactile stimuli are used. (C) 1994 John Wiley an d Sons, Inc.