Reappraisal of the F/M amplitude ratio in carpal tunnel syndrome.

摘要: The F-wave/M-wave amplitude (F/M-amp) ratio has been shown to be increased in peripheral neuropathies, provided the maximum M-wave is relatively preserved. Reduced amplitudes and central facilitation of antidromically-induced reactivation anterior horn cells' axon hillocks (F-wave) are believed contribute higher F/M-amp ratios. present study was undertaken re-evaluate mechanisms responsible for ratios carpal tunnel syndrome (CTS). We enrolled 232 cases affected by CTS 108 controls. Fand F-wave chronodispersion were analyzed median ulnar nerves. nerve subjects with moderate-severe damage significantly than that mild Chronodispersion increasing severity. conclude relative preservation due large diameter muscle afferent fibers monosynaptic response. Absence response makes small motoneurons, usually inaccessible antidromic volley because its collision orthodromic reflex volley, able fire F-wave.