Comparative Study of Electromyography and Hand Elevation Test in Carpal Tunnel Syndrome

ABSTRACT

PURPOSE: Since the hand elevation test was first introduced by Ahn in 2001, it has been one of most performing provocative test for diagnosing carpal tunnel syndrome. Although many studies have been published on the hand elevation test, there are no study that can explain why false-negative results of hand elevation test appears in carpal tunnel syndrome patients diagnosed by electromyography (EMG) findings. Therefore we searched out whether hand elevation test is related with EMG severity. MATERIALS AND METHODS: We made a retrospective study of 654 bilateral carpal tunnel syndrome patients. Among them 134 were studied which had different hand elevation test results on each hands. The paired samples t-test was used to compare the EMG severity of each group. The relationships between hand elevation test and EMG severity were examined using Pearson-product correlations. Comparing whether the frequency of false negative hand elevation were different between both hands, and whether the severity of EMG depends on which side of hand is, was evaluated with Mann-Whitney U-test. RESULTS: Severity of EMG in positive group was moderate to severe on average, whereas mild to moderate on negative group, with significant difference statistically (p<0.001). Correlation between the hand elevation test results and EMG severity also showed significance statistically (p<0.001). CONCLUSION: Mild severity of EMG was found out to be the factor affecting the false results. However, EMG severity and hand elevation test shows a meaningful correlation, supporting the value of hand elevation test.