Diagnosing narcolepsy can sometimes be challenging, but in the hands of a sleep specialist, it can be done.
Narcolepsy is a chronic sleep disorder that involves your brain’s ability to regulate your sleep-wake cycles.
If you have narcolepsy, you will have excessive daytime sleepiness and may involuntarily fall asleep during regular activities, such as driving, talking, or eating.
Narcolepsy can also affect your nighttime sleep cycle. You may frequently wake throughout the night or have restless sleep.
Tests are available to help identify the symptoms of narcolepsy and reach a diagnosis. A health professional who specializes in sleep medicine or neurology can typically provide this diagnosis.
Once they do, you can work together in determining the best course of action for your case.
Diagnosing narcolepsy typically starts with a detailed medical history and a physical exam conducted by a sleep professional or a neurologist who specializes in hypersomnia.
Hypersomnia means excessive sleepiness or excessive time spent sleeping.
During your visit with a sleep medicine expert, they might ask you to keep a sleep journal and log for 2 weeks.
In your journal, you’ll note your symptoms and details about your sleep episodes.
Sometimes, a sleep medicine expert may also recommend an actigraphy test to monitor your sleep and wake cycles. This is done with a small device worn on the wrist for a week or longer.
It’ll measure how much you move during the day because it’s based on the idea that you won’t move as much when you’re sleeping.
The rest of the physical exam may include a neurological examination, which can help rule out other conditions that could be causing your sleepiness symptoms such as obstructive sleep apnea.
Qualified sleep professionals you might want to reach out to include sleep medicine and neurology specialists, particularly those who specialize in hypersomnia.
A primary care physician may not be equipped to perform the necessary tests to diagnose narcolepsy. But they may be able to refer you to a sleep specialist in your area.
Before performing any tests, a sleep professional will want to explore the symptoms of narcolepsy established by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5).
These are some of the most common ones:
- involuntary sleep episodes throughout the day
- excessive sleepiness during the day
- visual hallucinations just before falling asleep or upon waking up
- inability to move for a few minutes right before falling asleep or upon waking up (sleep paralysis)
- occasional episodes when you suddenly stop talking or performing an activity
- sudden loss of muscle control while awake usually caused by strong emotions (cataplexy)
- irritability (in children)
- restlessness (in children)
- signs of early puberty (in children)
- vivid or frightening dreams (typically in children)
Frequency is also important for a diagnosis. According to the DSM-5, these symptoms must occur at least 3 times a week in the last 3 months.
To determine whether you have narcolepsy, your sleep specialist will also want to know if at least one of the following symptoms is present:
- episodes of cataplexy happening a few times a month
- low levels of
hypocretin, a hormone that helps suppress sleep and promote wakefulness
- entering rapid eye movement (REM) sleep within 15 minutes of falling asleep or falling asleep in an average of 8 minutes or less during a sleep study
In addition to your physical exam, medical history, and sleep log, your health professional may need to conduct specific tests to diagnose narcolepsy. These tests are typically performed at a clinic or sleep lab.
Two tests are used specifically for diagnosing narcolepsy:
A polysomnogram is conducted overnight. It records your brain activity, muscle movement, breathing, and eye movements while you sleep.
This test helps health specialists monitor REM sleep. It also helps rule out other conditions, such as obstructive sleep apnea. It also helps to ensure you get at least 6 hours of sleep the night before your other multiple sleep latency test.
Multiple sleep latency test (MSLT)
The multiple sleep latency test measures how quickly you fall asleep, which helps evaluate your level of daytime sleepiness. The MSLT also analyzes when you go into REM sleep.
The MSLT is done at a clinic or sleep lab the morning after your PSG.
During this test, you’ll be asked to take 5 naps of at least 20 minutes every 2 hours throughout the day.
Falling asleep in an average of 8 minutes or less over the 5 naps may indicate you have excessive daytime sleepiness.
The MSLT also evaluates how quickly you go into REM sleep. Going into REM sleep within 15 minutes during at least two of the 5 naps and the sleep study from the previous night might indicate you have narcolepsy.
Some medications can affect the results of this test. For this reason, you might be asked to take a drug test the morning of your MSLT. This ensures your test will be accurate.
Other possible tests
In addition to the two sleep studies, your health team may check hypocretin levels. This may be particularly important if your other tests are inconclusive.
To measure hypocretin, they’ll need to draw out a sample of your cerebrospinal fluid through a spinal tap. The cerebrospinal fluid is the fluid surrounding your brain and spinal cord.
Preparing for your PSG and MSLT tests typically requires gradually stopping any medications that work on your brain. For example, antidepressants and stimulants.
This needs to be done with the support of your health professional, to avoid any possible adverse effects.
At this moment, there are no at-home tests that can diagnose narcolepsy.
You’ll likely complete your sleep log at home, but the major portion of the narcolepsy testing is done overnight at a sleep center or lab.
Narcolepsy is a rare condition and can sometimes take years to diagnose. Often, narcolepsy symptoms resemble other conditions, and people may receive an incorrect diagnosis.
Depending on your age, narcolepsy may be mistaken for any of the following conditions:
- attention deficit hyperactivity disorder (ADHD)
- chronic fatigue syndrome
- seizure disorder
- learning disorder
- obstructive sleep apnea
Getting the correct diagnosis is essential to obtaining treatment and support for narcolepsy.
A sleep medicine specialist can help differentiate between narcolepsy and other conditions with similar symptoms.
Narcolepsy is a chronic neurological condition that affects your sleep-wake cycles. It’s often underdiagnosed and misdiagnosed, especially in children.
Common symptoms include excessive daytime sleepiness, loss of muscle tone, sleep paralysis, and visual hallucinations.
Narcolepsy cannot be diagnosed at home. To receive a diagnosis, you’ll need to see a sleep medicine specialist.
Diagnosing narcolepsy involves obtaining your medical history, a physical exam, and a series of tests conducted overnight at the sleep lab. These tests also help rule out other conditions that may resemble narcolepsy.
Once narcolepsy is diagnosed by a sleep specialist, symptoms can be managed and treatment is available.