Effects of Hypoglossal Nerve Stimulation on Cognition and Language in Down Syndrome and Obstructive Sleep Apnea

Inclusion Criteria: * Diagnosis of Down syndrome * Age 10-21 years * Prior adenotonsillectomy * Severe OSA (AHI \> 10, AHI \< 50, no more than 25% AHI attributable to central events) based on prior in-lab PSG performed after adenotonsillectomy and within 18 months of enrollment * Approval from at least two of the three physician reviewers based upon the results of a routine drug-induced sleep endoscopy (DISE) having occurred within 12 months of enrollment * Subjects must have either tracheotomy or be ineffectively treated with CPAP due to non-compliance, discomfort, un-desirable side effects, persistent symptoms despite compliance use, or refusal to use the device * Children and their parents/guardians must be willing to have stimulation hardware permanently implanted, and be willing to participate in follow-up visits, postoperative PSG, and questionnaire completion * Children's parents/guardians must complete a questionnaire confirming that their child is capable of communicating feelings of pain or discomfort. They must also confirm they are able to assess their child for adverse effects related to device implantation * Children and their parents/guardians must be proficient in English Exclusion Criteria: * Body mass index (BMI) above the 95th percentile for subject's age * Circumferential airway collapse at the level of the velopharynx observed during DISE * Other medical conditions resulting in medical instability (eg. congestive heart failure, recent open heart surgery, immunosuppression, or chronic lung disease or aspiration) * Presence of another medical condition requiring future magnetic resonance imaging (MRI) of the chest * Patients with another implantable device which could interact unintentionally with the Inspire system * Any contraindication for general anesthesia * History of bleeding or clotting disorders and those on blood thinning or NSAID medications for the week prior to implantation surgery. Subjects will be asked to refrain from the use of NSAIDS for two weeks after implantation or any revision surgeries * Subject is currently taking muscle relaxant medication * Life expectancy less than 12 months * Subject's inability to communicate pain or discomfort to their caretaker/parent, based on parental or investigator assessment * Nonverbal candidates will be excluded due to an inability to complete testing procedures including expressive language sampling * Subjects with a co-occurring diagnosis of autism spectrum disorder * Subjects that have a positive β-HCG * Subjects deemed unfit for participation by the investigator for any other reason