Objective
The previously established method of carpal tunnel syndrome (CTS) diagnosis is relatively troublesome and risk of misleading due to uncertainty of exact distance measurement for stimulation. If we use the wrist crease, an anatomical landmark, there might not be error in length measurement for stimulation at any wrist position. This study was performed to evaluate the wrist stimulation method in the diagnosis of CTS for it's convenience and reducing the errors.

Method
Seventy healthy adults and sixty-five patients with clinical and electrophysiologic evidence of CTS were studied. Sensory nerve action potentials (SNAPs) in second and fifth digit were recorded antidromically with stimulation at a distance of 14 cm from recording electrode and stimulation at wrist crease. The ratio and difference of distal latency and ratio of amplitude between median and ulnar SNAPs were assessed.

Results
The ratio and difference of distal latency and ratio of amplitude in the 14 cm stimulation method were 1.52⁑0.28, 1.59⁑0.91 msec, 1.26⁑0.27 in the right, 1.43⁑0.14, 1.29⁑0.42 msec, 1.18⁑0.20 in the left, respectively in the men patients, and those of women patients were 1.48⁑0.35, 1.43⁑1.04 msec, 1.18⁑0.30 in the right, 1.53⁑0.30, 1.46⁑0.80 msec, 0.75⁑0.36 in the left. In wrist crease stimulation, those of men patients were 1.72⁑0.39, 1.74⁑0.98 msec, 1.22⁑0.24 in the right, 1.53⁑0.21, 1.31⁑0.46 msec, 1.25⁑0.29 in the left, and those of women patients were 1.67⁑0.46, 1.56⁑1.01 msec, 0.63⁑0.32 in the right, 1.68⁑0.37, 1.56⁑0.82 msec, 0.68⁑0.30 in the left. These results showed a significant positive correlation between the patients group and the control group in two stimulation methods (p＜0.001).

Conclusion
Based on the result of this study, wrist crease stimulation method is a quick and easy procedure, which would be recommended in the early diagnosis of CTS.