Narcolepsy

A healthcare provider can suspect narcolepsy based on your symptoms. However, narcolepsy shares symptoms with several other brain- and sleep-related conditions. Because of that, the only way to diagnose narcolepsy conclusively is with specialized diagnostic tests.

Before doing most of the main tests for narcolepsy, a healthcare provider will first make sure that you’re getting enough sleep. That usually involves simple tracking methods for your sleep-wake patterns, such as actigraphy. This typically uses a watch-like device that you wear on your wrist to track movement patterns (such as when you’re sleeping vs. when you’re up and moving around while awake).

What tests will be done to diagnose narcolepsy?

Some possible tests for diagnosing narcolepsy include:

• Sleep study (polysomnogram).
• Multiple sleep latency test (MSLT).
• Maintenance of wakefulness test.
• Spinal tap (lumbar puncture).

Sleep study (polysomnogram)

A sleep study involves multiple types of sensors that track how you sleep. A key part of a full sleep study, formally known as a polysomnogram, is that it includes electroencephalogram (EEG) sensors. Those sensors track your brain waves, allowing healthcare providers to see what stage of sleep you’re in from minute to minute.

A sleep study can help diagnose narcolepsy because people who have this condition go into the REM stage sleep unusually fast compared to people who don’t. They’ll also have sleep broken up by periods of wakefulness, which the sleep study can also detect and record.

Another key reason why a sleep study is necessary is that excessive daytime sleepiness is also a main symptom of sleep apnea. A sleep study can rule out sleep apnea.

Multiple sleep latency test

This test involves testing whether or not you’re prone to falling asleep during the daytime. This test involves timed naps that happen in a specific timeframe. This test can help determine if a person has excessive daytime sleepiness, which is a required symptom of narcolepsy. This test often happens the following day after an overnight sleep study.

Maintenance of wakefulness test

This test determines if you can stay awake during the daytime, even in situations where it would be easy to fall asleep. While it’s not common in testing for narcolepsy, it’s still possible and can rule out other issues. It’s also useful for testing if stimulant treatments are helping.

Spinal tap (lumbar puncture)

This test can help determine if the orexin levels in your CSF are low. This is a key way to diagnose type 1 narcolepsy. Low orexin levels can also signal that someone with narcolepsy may develop cataplexy, even if they haven’t yet shown that symptom. Unfortunately, orexin levels don’t change in people with type 2 narcolepsy, so it isn’t always a test that helps with diagnosis.

Other tests

Many other tests are also common for people who have narcolepsy. An example of why this might happen is having cataplexy as a symptom. Cataplexy is similar to several other motor (movement-related) symptoms of brain conditions, such as atonic seizures (also known as drop attacks).

Because of that, healthcare providers might first test for more severe conditions like seizures and epilepsy, which means narcolepsy may take longer for providers to pinpoint and diagnose. Other tests are possible, too, and your healthcare provider is the best person to explain what tests they recommend and why.