A polysomnography, commonly referred to as a sleep study, is a test used to diagnose various sleep disorders. During this study, your sleep cycles and stages are monitored to determine if or when your sleep patterns are disturbed and why.

The Typical Sleep Cycle

The average process of falling asleep starts with a stage called non-rapid eye movement (NREM) sleep. At this stage, brain waves slow down. This is recorded during a sleep study with a test called an electroencephalogram (EEG).

After an hour or two of NREM sleep, brain activity spikes up again. This sleep stage is called rapid eye movement (REM) sleep. Our eyes quickly move back and forth during REM sleep and this is the stage when most dreaming takes place..

We typically go through multiple sleep cycles a night and cycle between NREM and REM sleep every 90 minutes or so. However, sleep disorders can interfere with this natural process.

Why Are Sleep Studies Performed?

These types of tests are usually performed when there are symptoms or doubts regarding sleep conditions. Moreover, they can help to determine an approach on how to treat those conditions or to analyze whether the completed treatments worked. Generally, those sleep conditions affect the brain, nervous system, breathing, and heart function.

The most common conditions that can be diagnosed during a sleep study include:

• Sleepwalking or other sleep behavior-related disorders.
• Certain types of seizures and epilepsy.
• Insomnia.
• Periodic limb movement disorder (including restless legs syndrome).
• Sleep apnea (obstructive and central).
• Night terrors (or sleep terrors).
• Nocturnal panic attacks.
• Other types of parasomnias and disruptive sleep disorders.
• Narcolepsy.
• Sleep paralysis.

How to Prepare for an Overnight Sleep Study

1. Discuss medications ahead of time: If your healthcare provider has told you to do so, stop taking your regular medications.
2. Pack an overnight bag with comfortable sleep clothes, a change of clothes, oral care products, makeup remover (if necessary), and a book (or other kind of reading material)
3. Refrain from drinking any type of caffeine (e.g., coffee, tea, soft drinks, chocolate) after lunchtime.
4. Do not take naps.
5. Avoid alcoholic beverages, as alcohol can interfere with sleep.
6. Make sure you wash any hair gel or other styling products out of your hair. They can interfere with monitoring equipment.

Overnight Sleep Studies: Home or  Sleep Lab?

At-home sleep studies are usually performed under the supervision of a healthcare provider to assess people with sleep-related breathing issues, like sleep apnea. Nonetheless, at-home sleep studies are not adequate for diagnosing other types of sleep disorders, why is that?

The portable equipment that is used for home studies cannot measure as many body functions during sleep as the equipment used in a sleep laboratory. For example, measurements of brain activity that can help diagnose sleep disorders such as seizures, periodic limb movements, or narcolepsy can only be taken in a lab.

If you wish to get an at-home sleep study, you must first ask your doctor or sleep specialist if this type of sleep study is appropriate for you. A doctor is in the best position to determine if the information provided by a home study can adequately evaluate your sleep issues, or if you would benefit from the wider range of measurements from an in-lab sleep study.