The effect of the median nerve compression test on median nerve conduction across the carpal tunnel

INTRODUCTION: We conducted an experimental, single-blind research study to determine the efficacy of using the median nerve compression test (MNCT) to improve the sensitivity and specificity of median nerve motor and sensory latencies for the diagnosis of carpal tunnel syndrome (CTS). We expected post-MNCT latencies to be prolonged in the CTS group. METHODS: A convenience sample of 18 subjects aged 18-65 was enrolled in this study. The CTS group consisted of 9 subjects with 14 hands tested having clinical signs and symptoms of CTS and normal baseline latency measures. The control group consisted of 9 gender- and age-matched (+/- 3 years) subjects with 14 hands tested. Three standard distal sensory latencies (DSL) and one distal motor latency (DML) were obtained, then repeated after application of the MNCT. RESULTS: No significant differences in latencies were found between groups (p = 0.76) or within subjects (p = 0.74) after application of the MNCT. There was less than 10% increase in sensitivities of post-MNCT latencies. DISCUSSION AND CONCLUSION: We found that the MNCT did not cause a meaningful increase in sensitivity or specificity of latencies for the diagnosis of CTS. The use of the MNCT as a method to prolong standard latencies is not recommended.