Provocative exercise maneuver: its effect on nerve conduction studies in patients with carpal tunnel syndrome.

This study examined the influence of a provocative dynamic exercise maneuver on nerve conduction studies (NCS) in three study groups: Group A, controls (n = 10); Group B, patients with clinical carpal tunnel syndrome (CTS), but normal NCS (n = 10); and Group C, patients with clinical CTS and abnormal NCS (n = 10). A wrist flexion-extension exercise was designed to increase pressure on the median nerve within the carpal tunnel to aid diagnosis by revealing latent nerve conduction slowing in patients presenting with clinical CTS but normal NCS. The exercise protocol was sufficient to evoke symptom exacerbation in 50% of the patients. The results showed that 4 minutes of this active provocative maneuver revealed a significant (p < .05) difference in the sensory distal latency (median) for digit IV; however, this was not clinically significant inasmuch as the change in latency was insufficient to meet the a priori criteria for NCS abnormality required for the electrodiagnosis of median nerve abnormality. There was no increase in the distal sensory latencies of those patients whose symptoms were exacerbated, when compared with those patients whose symptoms remained unchanged. There appears little diagnostic value in adding this particular active provocative wrist maneuver to the routine electrodiagnostic evaluation for carpal tunnel syndrome.