Simple and novel method to measure distal sensory nerve conduction of the medial plantar nerve.

A simple and reliable method for recording sensory nerve action potentials (SNAPs) of the medial plantar nerve is described. Medial plantar SNAPs were recorded by placing surface electrodes on the sole. Ring electrodes were used for orthodromic stimulation at the big toe. Sixty-four healthy subjects ranging in age from 13 to 81 years were examined to establish normal values. Mean amplitude for the medial plantar SNAP was 4.7 +/- 2.8 microV and mean maximum conduction velocity was 43.5 +/- 6.4 m/s. The normal values for amplitude obtained for the medial plantar SNAPs were higher than those obtained by the method of Guiloff and Sherratt, and the sensitivity of our method for diagnosis of early sensory neuropathy was relatively higher. The method should therefore be useful in the diagnosis of early sensory neuropathy.