Background and Purpose: Although the Flexor Carpi Radialis (FCR) H-reflex is recommended as a screening tool for proximal nerve disfunction, there has been concern that Carpal Tunnel Syndrome (CTS) might affect FCR reflex latency values. The purpose of this study was to determine if the FCR H-reflex latency is altered by the presence of CTS. Subjects and Methods: An exploratory design with a retrospective, observational approach was used. CTS subjects were former patients with CTS classified on each side into levels of severity. Control subjects were a volunteer sample of convenience with no evidence of CTS. Subjects were categorized into 4 groups by severity of CTS between the two arms with 14 subjects assigned to each group. The side-to-side mean latency difference of the FCR H-reflex for each subject was used to compute a single factor ANOVA. Results: There were no statistically significant differences among group means. The power of the F-test was adequate as determined by 95% CI analyses of the between-group differences relative to the minimal clinically important difference. Discussion and Conclusion: The FCR H-reflex latency is not altered by the presence of CTS.Therefore, an FCR H-reflex latency abnormality in a limb with CTS will be as likely to indicate disfunction along its neural pathway as the FCR H-reflex latency in a limb without CTS.
