Electrophysiologic studies of patients with neural muscular atrophy

: Various nerve conduction velocities, the terminal latency (TL) of facial nerve, the trigeminofacial reflex and fast auditory evoked potentials (FAEP) were investigated in 26 patients with peroneal muscular atrophy (22 with HMSN I and 4 with HMSN II). With the brain nerve status revealing no clinical abnormalities, 85.7% of HMSN I patients showed a longer-than-normal TL of the facial nerve, 66.6% had a prolonged early reflex component of trigeminofacial reflex and 22.7% pathological FAEPs. Normal neurophysiologic findings were obtained for brain nerves of HMSN II subjects. Subclinical involvement of the mid-group of brain nerves did not at all correlate with the impairment of extremity nerves and the duration of the disease. The present results reflect the heterogeneity of HMSN.