Evaluation of Relationship between Extensor Digitorum Communis Hoffmann-reflex Latency and Upper Limb Length and Age

BACKGROUND: The aim of this study was to evaluate the relation between normal values of extensor digitorum communis (EDC) Hoffmann-reflex (H-reflex) latency, upper limb length and age in normal participants, and to determine whether there is any regression equation between them. MATERIALS AND METHODS: In this cross-sectional study, 120 upper limbs of 76 normal volunteers (55 limbs of 34 men and 65 limbs of 42 women) were participated in this study. The onset latency of EDC H-reflex was determined with standard electrodiagnostic techniques and was recorded. RESULTS: The mean EDC H-reflex latency was 15.89 ± 1.41 ms. There was a positive significant correlation between EDC H-reflex latency and upper limb length (r = 0.749, P < 0.0001) and also arm length (r = 0.758, P < 0.0001), but there was a nonsignificant indirect correlation between age and EDC H-reflex latency (r = −0.111, P = 0.227). The relation between H-reflex and sex was not statistically significant (P = 0.46). CONCLUSION: According to our result, there are good predictive values between upper limb length and arm length for the estimation of normal EDC H-reflex latency.