Human Adult Deglutition during Sleep

Abstract

Clearance of the pharynx by deglutition is important in protecting the airway. The pattern of deglutition during sleep was investigated. Deglutition during sleep was examined in 8 normal human adults via time-matched recordings of polysomnography and surface electromyography (EMG) of the thyrohyoid and suprahyoid muscles. During sleep, deglutition was episodic, and was absent for long periods. The mean number of swallows per hour (+/-SD) during the total sleep time was 2.9 +/- 1.3. The mean period of the longest absence of deglutition was 50.6 +/- 10.2 minutes. Most deglutition occurred in association with spontaneous electroencephalographic arousal in rapid eye movement (REM) sleep and non-REM sleep. Deglutition was related to sleep stage. The mean number of swallows per hour was 7.2 +/- 3.5 during stage 1 sleep and 2.0 +/- 0.7 during stage 2 sleep. There was little deglutition during stages 3 and 4. The deeper the sleep stage became, the lower the mean deglutition frequency became. The mean number of swallows per hour was 2.7 +/- 2.2 during REM sleep. The EMG amplitude dropped to the lowest level of recording and hypotonic EMG activity increased during REM sleep. Deglutition, a vital function, is infrequent during sleep.