1 PROJECT SUMMARY/ABSTRACT 2 Obstructive sleep apnea (OSA) affects as much as 5% of children, and results in significant cardiovascular and 3 neurobehavioral morbidity if left untreated. The gold standard for evaluation of OSA in children is in-laboratory 4 polysomnography (PSG). However, PSG is resource-intensive, requiring caregivers to spend a night away 5 from home, and facilities are limited. Consequently, 90% of children who undergo adenotonsillectomy to treat 6 OSA never have the diagnosis made by PSG. Home sleep apnea testing (HSAT) is an alternative to PSG 7 where a patient has an unattended OSA assessment in their home. Clinical trials in adults showed no 8 difference in functional or treatment outcomes in those evaluated by HSAT compared to PSG, but similar 9 studies have not been conducted in children. The performance of HSAT compared to PSG in children is 10 unknown, and this has been a critical barrier to its clinical use as a diagnostic tool in the pediatric population. 11 HSAT has been shown to be feasible in children and our preliminary data have shown that HSAT may be 12 accurate compared to PSG and preferable to families. This milestone-driven comparative effectiveness trial will 13 compare HSAT to PSG for the evaluation of OSA in children through the following Aims: 14 1) Compare the diagnostic accuracy of HSAT with PSG for determining OSA status 15 2) Determine the agreement between HSAT and PSG results for therapeutic decision-making 16 3) Determine child/parent-reported acceptability of HSAT and preference of HSAT vs PSG. 17 To accomplish these aims, 317 children age 5-12 years old clinically referred for evaluation of OSA will 18 undergo HSAT and PSG within one week in random order and OSA classification between the two modalities 19 will be compared within subjects using receiver operating characteristics. Off-site investigators who are 20 pediatric sleep medicine physicians will provide a therapeutic decision based on clinical data and HSAT or 21 PSG result and agreement between therapeutic decision between the two tests will be assessed. Parent- and 22 child-reported questionnaires assessing preference and acceptability will be compared between HSAT and 23 PSG, and parent-reported feasibility of HSAT will be assessed. 24 The results of this comparative effectiveness trial will provide critical data directly comparing HSAT to the gold 25 standard in-lab PSG to determine its clinical utility. If shown to be diagnostically accurate and result in the 26 equivalent therapeutic decision as PSG, HSAT could provide a more patient-centered diagnostic alternative 27 that dramatically increase the capacity for OSA evaluation in children, reducing morbidity related to delayed 28 diagnosis and increasing objective testing prior to adenotonsillectomy.