Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Font Size

Diagnosing Narcolepsy

A narcolepsy diagnosis requires several tests. A doctor will perform a physical exam and an in-depth medical history to rule out other causes of symptoms. Keep in mind that having some of the major symptoms of narcolepsy doesn't necessarily mean you have narcolepsy.

In addition, several specialized tests, which can be performed in a sleep disorders clinic, usually are required before a diagnosis can be established. Two tests that are considered essential in confirming a diagnosis of narcolepsy are the polysomnogram (PSG) and the multiple sleep latency test (MSLT). In addition, questionnaires, such as the Epworth Sleepiness Scale, are often used to measure excessive daytime sleepiness.

Recommended Related to Sleep Disorders

Sleep Labs: Rx for Better Shut-Eye

Karen D.' s husband was not sleeping well. Every night after he settled into bed, Karen would start to snore -- loudly and all night long. "My husband had been complaining for years about my snoring, and it was getting worse," says Karen, of Boston. "Even when I went away with my girlfriends, no one wanted to share a room with me." While Karen's snoring was keeping everyone within earshot awake, it was also affecting her own sleep. For as long as she could remember, the Bostonian lumbered through...

Read the Sleep Labs: Rx for Better Shut-Eye article > >

Epworth Sleepiness Scale

During the Epworth Sleepiness Scale test, you will be asked to answer eight questions using a scale from zero (not at all likely to fall asleep) to three (very likely to fall asleep). The resulting total score is between 0 and 24. Scores of 0 to 10 are normal. Total scores 10 or above generally warrant further investigation.

Polysomnogram (PSG)

A sleep study, or polysomnogram (PSG), is a test performed in a sleep lab. It electronically transmits and records specific physical actions of the body while you sleep, such as muscle movement, breathing patterns, and brain activity. The recordings are analyzed by a qualified sleep specialist to determine whether or not you have a particular sleep disorder.

What to Expect During a PSG

If you're scheduled for a PSG, you will arrive at the sleep lab about two hours prior to bedtime without making any changes in your daily habits. You will be assigned to a private bedroom in a sleep center or hospital. Near the bedroom will be a central monitoring area, where the technicians will monitor you while you sleep. You will be hooked up to equipment that may look uncomfortable. However, most people fall asleep with little difficulty. Your whole night's sleep will be monitored and recorded.

Multiple Sleep Latency Test

Performed the morning after the overnight polysomnogram, also in a sleep lab, this test measures how long it takes a person to fall asleep (sleep latency) during the day. During this test, you will be asked to take four or five scheduled naps every two hours. The first nap starts two hours after awakening that morning. People with normal sleep and alertness take about 10-20 minutes to fall asleep. People with narcolepsy (and other causes of abnormal sleepiness) take a much shorter time (less than five minutes) to fall asleep.

Two weeks prior to these tests, you will be asked to keep a sleep diary that records bedtime, wakeup times, and nap times. Your doctor will work with you to create a plan to gradually eliminate medications that could affect the sleep test results.

WebMD Medical Reference

Reviewed by Melinda Ratini, DO, MS on October 07, 2014

Today on WebMD

fatigued senior woman
We’ve got 10 tips to show you how
Man snoring in bed
Know your myths from your facts.
Young woman sleeping
What do your dreams say about you?
woman eith hangover
It’s common, and really misunderstood.
Young woman sleeping
Cannot sleep
child sitting in bed
Woman with insomnia
nurse sleeping
Foods That Help Or Harm Your Sleep
Insomnia 20 Tips For Better Sleep
Pain at Night