Nerve conduction velocity varies inversely with height.

Even when all known factors affecting the determination of nerve conduction velocity are controlled, large individual variations persist. In 40 normal controls, we found that peroneal and sural conduction velocities varied inversely with body height (P less than 0.001). This height effect is not due to temperature differences, and it explains almost 50% of the intersubject variability in conduction velocity. We hypothesize that the height influence reflects abrupt, rather than gradual, tapering of axons distally. This mode of tapering may help explain the decrements in conduction velocity from proximal to distal nerve segments and from upper to lower extremities, which have long been observed in clinical electromyography. Clinical recognition of this height effect is important lest one label as abnormal an individual with mildly slowed peripheral nerve conduction velocity solely related to large stature.