Air pulse quantification of supraglottic and pharyngeal sensation: a new technique

There are no published studies evaluating the sensory capacity of the region innervated by the superior laryngeal nerve. A normal sensory capacity is important in this area, since hypesthesia or anesthesia of the pharynx and supraglottic larynx may result in dysphagia and aspiration. This often occurs after stroke or after ablative surgery of the pharynx and larynx. Evaluating the efficacy of restorative procedures for supraglottic and pharyngeal sensation is dependent on defining and quantifying the sensory deficit. We have developed a new, noninvasive method to measure sensation in the pharynx and supraglottic larynx. A puff of air--of precisely controlled duration and pressure--was delivered via a flexible telescope to the anterior wall of the pyriform sinus. Surface sensibility was determined according to the psychophysical method of limits by varying air pressure while holding puff duration constant. We conducted 204 trials in 20 healthy adults. The average sensory discrimination threshold was 2.09 +/- 0.15 mm Hg. An intraclass correlation revealed excellent consistency (R = .80). There was no statistically significant difference between the right and left sides. Brief air pulse stimulation is an easy, relatively safe, and reliable method of determining supraglottic and pharyngeal sensory discrimination thresholds.