Mandibular posture during sleep in patients with obstructive sleep apnoea

Vertical mandibular posture is thought to be related to narrowing of the up per airway, because mouth opening is associated with an inferior-posterior movement of the mandible and the tongue which influences pharyngeal airway patency. To test whether the mandibular posture is related to the occurrenc e and/or termination of obstructive sleep apnoea (OSA), the vertical mandib ular position was recorded intraorally using a magnet sensor during a stand ard sleep study in seven patients with OSA. Measurements were recorded duri ng sleep both in the supine and lateral recumbent positions. The percentage of total sleep time spent with mandibular opening greater than 5 mm was si gnificantly larger (P < 0.001) in patients with OSA (69.3 +/- 23.3%) compar ed with our previous results obtained from healthy adults without OSA (11.1 +/- 11.6%). The stage of sleep affected the vertical mandibular posture du ring sleep in the supine position, but not in the lateral recumbent positio n in patients with OSA, In non-rapid eye-movement sleep, mandibular opening increased progressively during apnoeic episodes and decreased at the termi nation of apnoeic episodes. In contrast, no significant change in mandibula r posture occurred in apnoeic episodes during rapid eye-movement sleep. It was concluded that the vertical mandibular posture is more open during slee p in patients with OSA than in healthy adults and that mandibular opening i ncreases progressively during apnoeic episodes and decreases at the termina tion of those episodes. (C) 1999 Elsevier Science Ltd. All rights reserved.