Suppression of Thyroarytenoid Muscle Responses During Repeated Air Pressure Stimulation of the Laryngeal Mucosa in Awake Humans: Thyroarytenoid Suppression by Air Pressure Stimuli

Repeated stimulation of the laryngeal mucosa occurs during speech. Single stimuli, however, can elicit laryngeal adductor responses (LAR). Our hypothesis was that the LAR to repeated rapid air pressure stimuli are centrally suppressed in humans. Hooked wire electrodes were inserted into the thyroarytenoid and cricothyroid muscles bilaterally and into the posterior cricoarytenoid muscle on one side. Pairs of air puff stimuli were presented to the mucosa over the arytenoids at pressure levels three times threshold with inter-stimulus intervals from 250 to 5000 ms. Bilateral thyroarytenoid responses occurred at around 150 ms to over 70% of initial stimuli. With repeated presentation at intervals of 2 seconds or less, the percent occurrence decreased to less than 40% and response amplitudes were reduced by 50%. Central suppression of adductor responses to repeated air puff stimuli may allow speakers to produce voice without eliciting reflexive spasms which could disrupt speech.