The primary goal of the current study is to test the central hypothesis that therapeutic efficacy of AtoOxy depends on underlying patient pathophysiology.~Aim 1 - We will use advanced analysis of clinical polysomnography to estimate the OSA traits and classify patients as 'predicted responders' or 'predicted nonresponders'. We will prospectively test whether AtoOxy efficacy is greater in predicted responders.~Aim 2 - Pooling preliminary and prospective data, we will test the hypotheses that the following pathophysiological traits are associated with, and therefore predict, greater efficacy: less-severe upper airway collapsibility (less improvement needed to re-establish airflow), lower loop gain (less severe ventilatory control instability), higher arousal threshold (greater scope for muscle activation without arousal), and greater upper airway muscle compensation (functional muscle reflex apparatus).~Aim 3 - We will test the hypothesis that treatment efficacy will be greater in patients with tongue-related upper airway obstruction per previous drug-induced sleep endoscopy results (anterior-posterior collapse patterns).
Atomoxetine-plus-oxybutynin therapy (AtoOxy) has been shown to substantially reduce obstructive sleep apnea severity (OSA) in about half of patients. Here, the investigators study which patients respond meaningfully to therapy using pathophysiological traits measured at baseline sleep studies.