Stapedial muscle electromyography in various diseases.

Stapedial muscle electromyograms (SEMGs), obtained by an averaging technique of electrocochleography, were studied in patients with various diseases. The latency of SEMG was prolonged in incomplete facial palsy (Bell's palsy and cerebellopontine angle tumor), with stapedial reflex (SR) of a small amplitude or without SR. In otitis media with effusion, in which SR could not be obtained, SEMGs were clearly observed and showed normal waveforms and latencies. In Meniere's disease and sensorineural hearing loss, SEMG waves had normal waveforms and latencies. These results indicate that the SEMG shows a normal waveform and latency when facial nerve function is intact, and that its latency is prolonged in incomplete paralysis of the facial nerve.