Electrophysiological studies and physical examinations in entrapment neuropathy: sensory and motor functions compensation for the central nervous system in cases with peripheral nerve damage.

We performed electrophysiological studies and objective physical examinations in 60 patients with carpal tunnel syndrome and 21 patients with cubital tunnel syndrome. Compared with our normal data, the sensory nerve conduction velocity across the wrist was defined as abnormal in 97% of the carpal tunnel syndrome patients, the corresponding value of the amplitude of the sensory nerve action potential was 58% and the value of the two point discrimination test was 28% while the value of the Semmes-Weinstein monofilament test was defined as abnormal in 64% of the cases. In cubital tunnel syndrome patients, motor nerve conduction velocity across the elbow was defined as abnormal in 91%, the amplitude of the M-wave was 96%, manual muscle testing was 63% and their side pinch strength was defined as abnormal in 24% of the cases. The functions of recognition are preserved in the cases with moderate damage of peripheral nerve due to the cancellation of synaptic occlusion. Motor performance also compensated in the central nervous system. Therefore the sensitivity of the objective physical examination is less than that of electrophysiological study of peripheral nerve itself. For entrapment neuropathy electrophysiological findings are more sensitive than the objective physical examinations.