Submitted on April 14, 2006
Accepted on December 18, 2006
Swallowing Function and Upper Airway Sensation in Obstructive Sleep Apnea
Vincent Jobin1, Victoria Champagne2, Josee Beauregard2, Isabelle Charbonneau3, David H McFarland3, and R. John Kimoff4*
1 Respiratory Division, University of Montreal, Montreal, Canada
2 Respiratory Division and Sleep Laboratory, McGill University Health Centre, Montreal, Canada
3 Department of Speech and Audiology, Univerisity of Montreal, Montreal, Canada
4 Respiratory Divison and Sleep Laboratory, McGill University Health Centre, Montreal, Canada
* To whom correspondence should be addressed. E-mail: john.kimoff{at}muhc.mcgill.ca.
The objective of this study was to determine whether impaired upper airway mucosal sensation contributes to altered swallowing function in Obstructive Sleep Apnea (OSA). We determined upper airway two-point discrimination (2PDT) and vibratory sensation thresholds (VST) in 15 males with untreated OSA and 9 non-apneic controls (CL). We then assessed swallowing responses to oropharyngeal fluid boluses delivered via a catheter. The threshold volume required to provoke swallowing and the mean latency to swallowing were determined, as was the phase of the respiratory cycle in which swallowing occurred (expressed as % of control cycle duration, % CCD) and the degree of prolongation of the respiratory cycle following swallowing (inspiratory suppression time, IST). There was a significant impairment of both 2PDT and VST in OSA subjects vs. CL. 2PDT values were positively correlated with swallowing latency and threshold volume in CL but not OSA subjects. There was no difference between the 2 groups for threshold volume (median value = 0.1 (CI 0.1 - 0.2) (OSA) vs. 0.15 ml (CI 0.1 - 0.16) (CL), while swallowing latency was shorter for OSA patients (3.3 ± 0.7 (SD) (OSA) vs. 3.9 ± 0.8 (CL) sec, p = 0.04). Values for % CCD and IST were similar for OSA and CL. However among OSA subjects there was a significant inverse relationship between VST and IST values. These findings suggest the oropharyngeal sensory impairment in OSA is associated with an attenuation of inhibitory modulating inputs to reflex and central control of upper airway swallowing function.
