Sensory discrimination in the larynx and hypopharynx.

The traditional approach to evaluating swallowing disorders has focused on upper aerodigestive tract motor function. The evaluation of the sensory apparatus in the larynx and pharynx as part of the workup of dysphagia has heretofore not been addressed. The purpose of this work is to discuss a new, noninvasive method to measure sensory discrimination in the supraglottic larynx and hypopharynx. An air pulse, of precise duration and pressure, was delivered through a flexible fiberoptic telescope to the submucosally situated superior laryngeal nerve along the anterior wall of the pyriform sinus. Three hundred sixty trials were conducted in 30 healthy adults. The average sensory discrimination was 2.24 +/- 0.28 mm Hg. Brief air-pulse stimulation is a safe, reliable means of determining supraglottic and hypopharyngeal sensory discrimination thresholds.