A sleep study is a test that records the activity of the body during sleep. There are five main types of sleep studies that use different methods to test for different sleep characteristics and disorders. These include simple sleep studies, polysomnography, multiple sleep latency tests (MSLTs), maintenance of wakefulness tests (MWTs), and home sleep tests (HSTs). In medicine, sleep studies have been useful in identifying and ruling out various sleep disorders. Sleep studies have also been valuable to psychology, in which they have provided insight into brain activity and the other physiological factors of both sleep disorders and normal sleep. This has allowed further research to be done on the relationship between sleep and behavioral and psychological factors.
- Sleep-related breathing disorders, such as sleep apnea
- Sleep-related seizure disorders
- Sleep-related movement disorders, such as periodic limb movement disorder, which is repeated muscle twitching of the feet, legs, or arms during sleep. Sleep studies may be used to diagnose or rule out restless legs syndrome (RLS). However, RLS usually is diagnosed based on signs and symptoms, medical history, and a physical exam.
- Problems sleeping at night (insomnia): caused by stress, depression, hunger, physical discomfort, or other problem.
- Sleep disorders that cause extreme daytime tiredness, such as narcolepsy or circadian rhythm sleep disorders.
- Problems with nighttime behaviors, such as sleepwalking, night terrors, or bed-wetting
- Bruxism or grinding of the teeth during sleep
- Problems sleeping during the day because of working at night or rotating shift work. This sleep problem is called shift work sleep disorder.
- Sleep studies can also determine problems with stages of sleep. The two primary categories of sleep are non-rapid eye movement (NREM) and rapid eye movement sleep (REM). Normally, four to five series of NREM and REM make up a night's sleep. A change in this cycle may make it hard to sleep soundly
Types of Sleep Studies
There are four kinds of sleep studies.
Diagnostic overnight PSG monitors your general sleep and certain body functions, including breathing, oxygen levels in your blood, heart rhythms, and limb movements.
Diagnostic daytime multiple sleep latency test (MSLT) can help diagnose narcolepsy and check your degree of daytime sleepiness. It measures how quickly you fall asleep in quiet situations during the day. It also monitors how quickly and how often you enter the sleep stage called REM sleep. You’ll have this test the morning after a diagnostic overnight PSG.
Two-night evaluation PSG and CPAP titration. On the first night, you'll be monitored and evaluated. If the medical team finds that you have sleep apnea, you'll come back for a second night to figure out the right air pressure for CPAP (continuous positive airway pressure) treatment. It delivers air into your airways through a specially designed nasal mask.
Split-night PSG with CPAP titration. You’ll have this test if the medical team finds or suspects moderate or severe sleep apnea during the first part of the night's study. The second half of the test figures out the CPAP level needed to treat your apnea.