Nerve conduction studies in man

Abstract

Conduction velocity in the largest motor, sensory, and reflex fibers in the median, ulnar, common peroneal, and posterior tibial nerves was determined in normal man. The rate of conduction was greatest in the H reflex fibers, followed by the afferent fibers, and was least in the motor fibers. Proximal segments in all fibers conducted faster than distal ones. After the age of 50, there was a decrease in nerve conduction velocity, which was more apparent in upper than lower extremities, involved all fibers tested, and was more prominent distally. Associated with this, there was mild slowing of the conduction rate of the median nerve at the wrist and ulnar nerve at the elbow. In a group of patients with diabetes mellitus without clinical signs or symptoms of peripheral neuropathy, there was a mild decrease in conduction velocity. This was noted in all nerves and fibers but was most prominent in distal segments. In a group of patients with diabetes mellitus, with clinical signs and symptoms of peripheral neuropathy, there was a greater decrease in conduction velocity. This involved all fibers and nerves and was most prominent distally. There was also prominent slowing in the median nerve at the wrist and ulnar nerve at the elbow, sites of chronic compression.