Objective
To evaluate the effect of local cooling on the parameters of electrodiagnostic study of the patients with carpal tunnel syndrome.

Method
Twenty subjects with carpal tunnel syndrome and fifteen normal subjects were enrolled. The latency and conduction velocity of median motor and sensory nerves at wrist and elbow were measured with the different skin temperature at 32^oC as a baseline, and at 20^oC after cooling of mid-palm area by cold water immersion.

Results
The distal motor and sensory onset latencies were prolonged, and the sensory nerve conduction velocity was decreased after local cooling in both the patients and normal control group (p＜0.01). The differences of distal motor and sensory onset latencies, and sensory nerve conduction velocity between before and after local cooling were statistically significant in patients group (p＜0.01) compared with control group.

Conclusion
These results showed that the patients with carpal tunnel syndrome reacts differently to temperature changes compared with normal control in electrodiagnostic study.