Response of the Human Larynx to Sensory Cranial Nerve Stimuli

Abstract

The responses of the human larynx to some sensory cranial nerves stimuli were studied. Ten healthy adults during phonation at constant pitch and loudness received repeated click sound stimuli in both ears, photo stimuli in both eyes or electrical stimuli in a supra-orbital nerve. The muscle activity of the larynx was recorded with bipolar hooked wire electrodes inserted into the crico-thyroid muscles and or lateral crico-arytenoid muscles. The induced EMG potentials were full-wave rectified and averaged about eighty times and the activity change in the intrinsic laryngeal muscles caused by the sensory cranial nerve stimulation was determined.
Increased muscle activity was observed in most subjects who received sound or electrical stimulation, but not in those who received photo stimulation. The mean latent time from the stimulus to the maximum amplitude of muscle activity induced by the electrical stimulation to a supra-orbital nerve was longer than that by sound stimulation. The latency to the maximum amplitude of the response wave contralateral to the supra-orbital nerve stimulation tended to be longer than that ipsilateral to the stimulation.