Pediatric/Adolescent WatchPAT 400 Reliability Pilot Study

The goal of this clinical trial is to learn whether a newer sleep-testing device gives results that closely match the standard overnight sleep study, in children and adolescents ages 6-18 who are being evaluated for possible sleep apnea. The main questions it aims to answer are: Does the new device (WatchPAT 400) give breathing and oxygen level results that agree with the standard overnight sleep study (polysomnography)? How reliably can two doctors, each looking at only one test's results, arrive at similar conclusions about a child's sleep apnea? Participants will: Have their regular, already-scheduled overnight sleep study performed exactly as usual Wear the WatchPAT 400 device (a small sensor on one finger, a wrist unit, and one adhesive patch on the chest) at the same time, during that same night Have both sets of results reviewed separately by two different study doctors Researchers will compare the results from the WatchPAT 400 device to the results from the standard sleep study to see how closely they agree, and how well the new device performs at detecting sleep apnea in children and teenagers.

Inclusion Criteria: * Age 6-18 years at time of enrollment * Referred to the sleep clinic for Sleep disordered breathing symptoms. * Scheduling for a technician-attended in-laboratory polysomnogram (PSG) * Obstructive Sleep Apnea-18 (OSA-18) questionnaire score ≥60 * No neurodevelopmentally disability * Parent/legal guardian able and willing to provide written informed consent (participants who are 18 years old provide their own consent); participant able to provide age-appropriate assent where applicable * Finger, hand, and chest anatomy able to accommodate the WatchPAT 400 finger probe, wrist unit, and chest sensor patch Exclusion Criteria: * Known peripheral vascular disease, Raynaud phenomenon, or other condition affecting digital arterial pulsation * Current use of alpha-adrenergic blocking agents or other medications known to significantly affect peripheral vasomotor tone * Permanent cardiac pacemaker, atrial fibrillation, or other clinically significant arrhythmia at the time of study * Known neurodevelopmental disability (Trisomy 21, autism spectrum disorder, or similar), as above * Prior amputation, digital deformity, or injury to the fingers precluding probe placement * Inability or unwillingness to tolerate simultaneous placement of both the PSG and WatchPAT sensors * Known latex or adhesive allergy relevant to device sensor materials * Pregnancy, for adolescent participants where applicable