An important test to evaluate the functional state of the peripheral nerves is their conduction velocity. Due to large individual variations and to various other factors, for instance age, room temperature, and the hour of experiment, the results show a wide range even with normal subjects in good health.1-3 Therefore, when examining individual cases, frequently it will not be possible to gain conclusive evidence of a pathological condition, even if a significant slowing of conduction time could be demonstrated statistically in peripheral nerve diseases.
According to the results available so far, the evaluation of the difference in conduction velocities between the fastest and the slowest a motor fibers (range) seems to give a better impression of pathophysiological conditions. As early as 1954, Bolzani4 assumed the existence of such differences in motor nerve fibers of analogous functions. Also Merton5 explained his findings by a difference of conduction times