Influence of head position on obstructive sleep apnea severity

Objective Supine body orientation plays an important role in precipitating upper airway collapse in a significant proportion of obstructive sleep apnea (OSA) patients known to have supine-predominant OSA (OSAsup). Traditionally, trunk position is used to assess OSAsup, but the role of the head position has not been established. We hypothesized that head position influences OSA independently of trunk position. Methods Head and trunk positions were determined from subjects undergoing overnight polysomnography. The apnea-hypopnea index (AHI), rapid eye movement (REM), and non-REM sleep time of all trunk and head positions (lateral and supine) were calculated and compared against the complete supine position, i.e., head and trunk supine. Results In 26 subjects, lateral rotation of the head to the right or left with the trunk supine resulted in a significant reduction in AHI from 36.0 ± 22.5 to 25.8 ± 16.6 ( p = 0.008), and an AHI drop