Short Segment Conduction Study of Median and Ulnar Nerves in the Diagnosis of Carpal Tunnel Syndrome

ABSTRACT

OBJECTIVE: To compare the latency difference of median and ulnar sensory nerves through the wrist-palm short segment in patients with carpal tunnel syndrome (CTS). METHOD: Subjects included 68 hands of 36 carpal tunnel syndrome patients and 97 hands of 53 healthy adults with no electrophysiologic evidence of CTS. The median and the ulnar sensory responses were recorded on the third and the fifth digit using bar recording electrode, respectively. Both nerves were stimulated just proximal to the distal wrist crease and 5 cm distal to the proximal stimulation point. The latency differences between the 2 stimulation points were obtained. RESULTS: The transcarpal short segment conduction times in the control group were 1.0+/-0.1 msec and 0.9+/-0.1 msec for the median and ulnar nerves, respectively. The transcarpal short segment conduction times in the patients with CTS were 1.9+/-0.5 msec and 1.0+/-0.3 msec for the median and ulnar nerves, respectively. The transcarpal short segment conduction time difference between the median and ulnar nerves were 0.13+/-0.12 msec in the control group and 0.88+/-0.50 msec in the CTS group. The difference of transcarpal conduction of two nerves was statistically significant in comparison with the two groups. CONCLUSION: Wrist-palm short segment study of median and ulnar sensory nerve may be used adjunctively in diagnosis of mild CTS.