Sensory conduction in peroneal and posterior tibial nerves using averaging techniques.

A method of obtaining pure sensory nerve conduction velocities in the lower extremities is described. This involves the use of electronic summation (signal averaging). Potentials were obtained and velocities calculated from all normal subjects examined. In patients with peripheral neuropathies it was often possible to obtain nerve velocities with signal amplitudes as low as 0·1 μV and these were often slower than those obtained from the normal subjects. The advantages and disadvantages of this method are discussed. It is of significant clinical value in that pure sensory nerve conduction velocities can be measured in the legs when this may be the only valuable parameter in the absence of motor involvement. In addition, investigation of neuropathies at an earlier stage of development and recovery may be facilitated. It is hoped that in the future this technique of obtaining low amplitude responses with an analogue averager can be incorporated with the more routine aspects of nerve conduction testing when clinically indicated.