A sleep doctor, also known as a pulmonologist or an otolaryngologist, is a medical professional who specializes in diagnosing and treating disorders related to sleep. They have expertise in understanding various aspects of sleep such as sleep apnea, insomnia, narcolepsy, restless leg syndrome, and other sleep-related breathing disorders. A sleep doctor may use different methods like polysomnography or multiple sleep latency tests (MSLT) to diagnose a patient's condition. They also provide treatment options such as continuous positive airway pressure (CPAP), medication, lifestyle changes, and other therapies tailored to the individual needs of their patients.