Sleep Study Home A-Z Health Information Health Library A-Z Sleep Study Overview A sleep study, also known as polysomnography, is a comprehensive test used to diagnose sleep disorders. It records the brain waves, oxygen levels in the blood, heart rate, breathing, as well as eye and leg movements during sleep. It also measures eye and leg movements.The test is usually performed at night. However, it may be done during the day for shift workers who usually sleep in the daytime. In addition to diagnosis, a sleep study might help determine a treatment plan in case of a sleep disorder diagnosis. It also might be used to adjust treatment. Your health care provider may recommend a sleep study for cases suspected of: Sleep apnoea or another sleep-related breathing disorder: In this condition, breathing stops and starts repeatedly during sleep.Periodic limb movement disorder: People with this sleep disorder flex and extend their legs while sleeping. This condition is sometimes linked to restless legs syndrome. Restless legs syndrome causes an uncontrollable urge to move the legs while awake, usually in the evenings or at bedtime.Narcolepsy: People with narcolepsy experience overwhelming daytime drowsiness. They can fall asleep suddenly. Rapid eye movement (REM) sleep behaviour disorder: This sleep disorder involves acting out dreams during sleep.Unusual behaviours during sleep: This includes walking, moving around, or rhythmic movements during sleep. Unexplained long-lasting insomnia: People with insomnia have trouble falling asleep or staying asleep Purpose of Sleep Studies Diagnose Sleep Disorders like sleep apnoea, narcolepsy, restless legs syndrome, insomnia.Investigate Sleep-Related Behavioural disorders like sleepwalking, night terrors and other unusual activities during sleep.Evaluate Treatment Efficacy, i.e., how well the treatment for a sleep disorder is working, which includes titration sleep study. Types of Sleep Studies Polysomnography (PSG): It is the most common sleep study. PSG requires the patient to sleep overnight in a sleep disorder clinic (i.e., Level 1 sleep study). Levels 2, 3 and 4 include home-based sleep studies. The number of monitoring parameters reduces as the level of sleep study increases.Multiple Sleep Latency Test (MSLT): This test measures how quickly you fall asleep in a quiet environment during the day.Maintenance of Wakefulness Test (MWT): This test evaluates your ability to stay awake during the day. Preparation Avoid caffeineFollow specific instructions regarding medication use During the Study Setup: Sensors are placed on the scalp, face, chest, limbs, and a finger.Monitoring: The equipment monitors sleep stages and cycles, heart rate, breathing, oxygen levels and movements.Environment: Measurements are taken in a comfortable, quiet room for overnight studies. After the Study A specialist will analyse the data. A follow-up appointment will be scheduled to discuss the results and potential treatments.