Overnight Sleep Testing
Overnight polysomnograms are used to diagnose a large variety of sleep disorders using a large variety of equipment. Typical sleep disorders diagnosed by a PSG are:
- Sleep-related breathing disorders such as obstructive sleep apnea, central sleep apnea, sleep-related hypoventilation disorders, and more
- Central disorders of hypersomnolence such as narcolepsy and idiopathic hypersomnia.
- Parasomnias (abnormal behaviors/actions during sleep) such as sleep walking (somnambulism), REM behavior disorder (RBD), sleep paralysis, and more.
- Sleep-related movement disorders such as restless leg syndrome (RLS), periodic limb movement disorder (PLMD), bruxism, and others.
- Circadian rhythm sleep-wake disorders such as advanced sleep phase syndrome (ASPS), delayed sleep phase syndrome (DSPS), Non-24-hour sleep-wake syndrome, and more.
CPAP titration tests are also held overnight. They usually follow a PSG from a previous night and are used to determine appropriate oxygen pressure levels for controlling sleep apnea events.
PSGs are occasionally performed during the day. Patients with certain circadian rhythm disorders in which their typical bedtime is during the day, may want a PSG test administered during their normal sleep schedule.
Sleep disorders such as narcolepsy and idiopathic hypersomnia (IH) may be conducted during the day in a variation of a PSG test. Two typical daytime tests include the multiple sleep latency test (MSLT) and the maintenance of wakefulness test (MWT).
MSLTs are generally used to distinguish between narcolepsy and IH.
- MWTs are usually administered either to see if previous prescribed treatments for certain sleep disorders are successful, or if one’s ability to stay awake in a certain occupation is a concern.
- Insomnia is rarely tested by a PSG and is usually diagnosed by a simple consultation in discussing sleep troubles. However, if the insomnia is chronic with unexplained causes, a PSG might be used to help rule out any other underlying sleep disorder.