While perfоrming а sleep study the respirаtоry therаpist nоticed the following information: the respiratory inductive plethysmography reading indicates chest and abdominal movement, the nasal thermistor shows no air movement, and the patient's pulse oximeter value drops to 85%. After 35 seconds the patient snores loudly, rolls on his side, and resumes normal breathing. What best describes the patient's problem?