The electrophysiological studies of 45 patients with Charcot-Marie-Tooth disease (CMT) are presented. The nerve conduction of the motor median and ulnar nerves permitted us to separate our patients in two types: type I (demyelinating) with motor nerve conduction (MNC) below 38 m/s (11 cases) and type II with MNC normal or above 38 m/s (34 cases). In type I there was no correlation between reduction in MNC and clinical severity. It was not possible to classificate the disease on the sural nerve sensory action potential (SAP). They were unobtainable in most cases. In many patients with CMT type II the MNC was normal. In the cases the sural SAP was absent or reduced. We concluded that the MNC study is the best useful test to classify CMT disease in type I and type II.
Charcot-Marie-Tooth disease; nerve conduction velocity; electromyography