Effects of topical anesthetic on the pharyngeal sensory evoked potential

Abstract

Intact sensation to the upper airways is an integral part of safe and efficient swallowing. The initiation of the pharyngeal stage of swallowing is dependent upon sensory information, largely from mechanoreceptors located in the posterior pharyngeal wall. Degradation of sensory function in that area commonly results in dysphagia (disordered swallowing) characterized by a delay in the initiation of swallowing and discoordinated motor output. It was hypothesized that application of topical anesthetic directly to the surface of the posterior pharyngeal wall would result in quantifiable changes in the pharyngeal sensory evoked potential (PSEP) waveform. Healthy volunteers between the ages of 18 and 35 participated in the study. PSEPs were measured via 32 electrode cap (10–20 system) connected to SynAmps2 Neuroscan EEG System. Paired‐pulse air puffs were delivered to the oropharynx using a thin polyethylene tube connected to a flexible laryngoscope under two conditions. Condition 1 consisted anaesthetized posterior pharyngeal wall, and in condition 2 a topical anesthetic (2% viscous lidocaine) was applied to the posterior pharyngeal wall. Anesthesia resulted in alterations in PSEP waveform, including significant decreased amplitude of the N100 PSEP peak. These results demonstrate the PSEP is mediated in part by mucosal receptors.Research support by NIH T32‐TNCSD