Sleep Study
A sleep study, or polysomnography, records body functions during sleep to diagnose sleep disorders such as sleep apnea, insomnia, and narcolepsy.
Overview
A sleep study (polysomnography) measures and records body functions while you sleep, including breathing rate, blood oxygen levels, heart rate, brain waves, and leg and eye movements. These tests are essential for diagnosing sleep disorders, which can impact your overall health, safety, and quality of life.
What is it used for?
Sleep studies diagnose conditions that cause irregular sleep patterns, including:
- Sleep apnea: Repeatedly stopping breathing during sleep.
- Insomnia: Difficulty falling or staying asleep.
- Restless leg syndrome: Uncomfortable sensations in the legs with an urge to move them.
- Narcolepsy: A neurologic condition causing extreme daytime sleepiness.
What happens during a sleep study?
Studies can be conducted in a hospital/clinic or at home.
In-clinic study: You stay overnight in a private room. Technologists attach electrodes to your scalp, eyelids, chin, chest, and legs to record body functions. A pulse oximeter is placed on your finger or ear to monitor oxygen levels. You are monitored via video and audio equipment throughout the night.
Home sleep study: You receive equipment from your provider with instructions on how to attach sensors yourself. This test is specifically used to diagnose obstructive sleep apnea and is not recommended if you have other complex sleep disorders or health conditions.
Preparation
To ensure accurate results, follow these steps before your test:
- Avoid alcohol and caffeine in the afternoon and evening.
- Do not nap during the day.
- Avoid using lotions, hair gels, makeup, or nail polish, as these can interfere with electrode or pulse oximeter readings.
Understanding Results
Your provider will review several key metrics:
- Apnea Hypopnea Index (AHI): Measures episodes of sleep apnea; more than five episodes per night likely indicates sleep apnea.
- Sleep efficiency: The ratio of time spent sleeping versus time spent in bed.
- Oxygen Desaturation Index (ODI): Measures drops in oxygen levels; levels below 90 percent are considered abnormal.
- Heart rate: Monitors for abnormal heart rhythms during sleep.
Treatment Options
If diagnosed with sleep apnea, your provider may recommend lifestyle changes (weight loss, avoiding alcohol, quitting smoking), a CPAP machine (which provides steady air pressure to keep airways open), or dental devices like a mandibular advancement device to keep the jaw and tongue in a position that prevents airway blockage.