P080 State-dependency of nocturnal swallowing in healthy adults: Incidence, motor function and coordination with breathing

Abstract

Abstract Introduction Swallowing involves a complex motor pattern and coordination with breathing and other oro-motor behaviors. Sleep has major depressive effect on many of the motor neuronal pools that facilitate swallowing, particularly upper airway muscles. This study examines the state-depedence of the swallow motor program and coordination with breathing. Methods Adult subjects recruited from community undertook an overnight sleep laboratory study. Subjects were instrumented to monitor sleep (EEG), breathing (nasal mask, pneumotach), swallowing / airway valving events (epiglottic pressure, submental EMG) and pharyngeal muscle activity (peroral genioglosuss EMG electrodes).We report preliminary findings (N=5; 2 female; age: 23-57 yrs) from an ongoing study. Data reported mean ± SD. Results Nocturnal swallowing occurred intermittently thoughout the night, the majority triggered during an arousal from sleep (43-98% of all nocturnal swallows). Pharyngeal swallowing pressure was 147±44 cmH2O during quiet wake, 137±25 cmH2O during arousal from sleep, and 78 ± 23 cmH2O in stable sleep (p=0.02, RM-ANOVA). Swallows generated a brief, near-maximal burst of genioglossus EMG activity during quiet wake (90 ± 2 %, N=2) and during arousal from sleep (107 ± 24 %). In stable sleep, swallow EMG activity was 34 ± 1 %. Swallows during wakefulness occurred during expiration, the vast majority bracketed by expiration (Ex/Ex). Swallows in sleep, or during arousal from sleep, occurred in all phases of the respiratory cycle. Conclusions Swallows elicited during arousal from sleep generate ballistic EMG and pharyngeal pressures equivalent to wake state. In contrast, swallowing in stable sleep produces a markedly attenuated EMG and pharyngeal pressure.