Maximal nerve excitability testing versus neuromyography: prognostic value in patients with facial paralysis

Neuromyography (NMG) is compared with maximal nerve excitability testing (NET) as a prognostic tool in facial paralysis. Normal latencies, summation muscle action potentials, and test/retest reliability were determined in three groups of subjects. NMG was performed in 33 control subjects of Group 1 to determine test/retest reliability. To determine the range of normal facial nerve conduction latency and amplitude and configuration of the summation muscle action potentials, NMG was performed in 172 otolaryngologic control patients without facial paralysis. NMG and NET were then compared in Group 3, which consisted of 43 patients with Bell's palsy. Fluctuations in NMG were then analyzed in a fourth test series of three subjects from Group 1, in whom summatin muscle action potentials at various positions of the electrodes were compared. The high rate of fluctuations observed indicates the need for further assessment of test/retest reliability and standardization of normal values in NMG. Our results indicate that maximal NET is more reliable than NMG for prognosis of facial paralysis.