A middle-aged patient is having a sleep study. For which reason would you expect the patient to be prescribed a continuous positive airway pressure (CPAP) machine?

Continuous positive airway pressure, commonly known as CPAP, is the first-line treatment for obstructive sleep apnea. Sleep apnea is a disorder in which the upper airway repeatedly collapses during sleep, causing apneic episodes, oxygen desaturation, and frequent arousals that disrupt the normal sleep architecture. A sleep study, or polysomnography, is the standard diagnostic test used to confirm sleep apnea by recording airflow, oxygen saturation, chest wall movement, and brain activity during sleep. CPAP delivers a constant stream of pressurized air that acts as a pneumatic splint to keep the airway open, preventing collapse. Middle-aged adults are at particularly high risk for obstructive sleep apnea. Insomnia is characterized by difficulty falling or staying asleep and is treated with behavioral interventions, sleep hygiene education, and sometimes pharmacotherapy — not CPAP. Restless leg syndrome involves uncomfortable sensations and urge to move the legs; its treatment includes dopaminergic agents or gabapentin. Narcolepsy is a neurological disorder of excessive daytime sleepiness and cataplexy, treated with stimulants and sodium oxybate. CPAP is specifically indicated for sleep apnea and no other condition listed.