Influence of sleep posture on response to oral appliance therapy for sleep apnea syndrome

Study Objective: This study evaluated the effect of sleep posture on oral appliance therapy to elucidate the interindividual difference of response to the device. Design: Seventy-two unselected patients with sleep apnea syndrome were studied polysomnographically before and after insertion of the individually fabricated and adjusted device. Sleep positions were measured using a body position sensor. The patients were classified into three groups; supine, lateral and prone groups, according to the position in which apneas were most frequently observed. Setting: N/A Patients or Participants: N/A Interventions: N/A Measurements and Results: The mean apnea-hypopnea index (AHI) of all patients before treatment [43.0 +/- 25.6 (SD)] was significantly (p<0.0001) decreased after insertion of the appliance (21.6<plus/minus>18.3). The device decreased the mean AHI significantly from 29.8 to 11.3 in the supine position and 5.5 to 1.6 in the prone position, and increased, but not significantly, from 7.7 to 8.7 in the lateral posture. The supine (n=44) and prone (n=13) groups showed significant reduction of AHI with the oral appliance, while the lateral group (n=15) revealed only a slight decrease, although not significantly Responders defined by AHI < 10 accounted for 61.4% in the supine group, 0% in the lateral group and 84.6% in the prone group. Responders defined by a 50% drop in AHI accounted for 84.1%, 6.7%, and 46.7%, respectively. Conclusions: The effectiveness of oral appliance therapy is greatly influenced by sleep posture. Sleep posture recorded by polysomnography may be useful to predict the future success or failure of the device.