It Is Well Documented That Patients with Obstruc- Tive Sleep Apnea (osa) Often Have More Apnea Events in the Supine Position than in the Lateral Position,1-

IT IS WELL DOCUMENTED THAT PATIENTS WITH OBSTRUCTIVE SLEEP APNEA (OSA) OFTEN HAVE MORE APNEA EVENTS IN THE SUPINE POSITION THAN IN THE LATERAL POSITION,15 and positional treatment is effective in these patients.6 The positional OSA patients are reported to be thinner and have less severe apnea than nonpositional patients.3 An anatomic study of upper airways in OSA patients revealed that positional patients have a larger minimum crosssectional area and a larger minimum lateral distance than nonpositional patients, and they show an increase in anteroposterior distance when turning to the lateral position.7 Therefore positional OSA is considered to be a less severe subgroup in OSA. Patients with OSA almost always have habitual snoring, and habitual snoring without OSA is thought to be a precursor to OSA.8 Therefore it is anticipated that position affects snoring as well. Anecdotally it is known that many patients snore less in the lateral position than in the supine position.9 However, to date there has been no detailed study focusing on the positional dependency of snoring. Thus the main purpose of this study was to describe the effect of position on snoring in nonapneic snorers and OSA patients. We also described the effect of sleep stage, which is also known to affect apnea events, on snoring in those subjects.