Symptoms & Diagnosis: Narcolepsy

Symptoms

There are many signs and symptoms that patients with narcolepsy may exhibit. The list below describes many of the symptoms that are common amongst patients with narcolepsy. For more information on the individual symptoms, please visit one of the websites listed on the left-hand side of the page.

Diagnosis

There are several methods that are currently in use by physicians for diagnosing patients with narcolepsy. Typically, the patient's primary care doctor will evaluate any symptoms that could be related to narcolepsy. Using this information, the doctor will then determine whether or not it's necessary for the patient to see a sleep specialist. These doctors specialize in diagnosing patients suffering from sleep disorders and will be responsible for the treating the patient. The sections below give a brief description on the various techniques used to diagnose patients suffering from narcolepsy.

Hypocretin Test

The hypocretin test measures the levels of hypocretin in the fluid that bathes the spinal cord. Narcolepsy has been linked to having low levels of hypocretin, making this a good indicator for patients with narcolepsy.

Polysomnogram

A polysomnogram, or PSG, requires the patient to stay overnight at a sleep center. A PSG is painless and simply requires the patient to go to sleep as they normally would, except sensors will be placed on the finger, limbs, chest, face, and scalp. These sensors will record brain activity, eye movement, muscle activity, breathing rate, heart rate, blood oxygen levels, and the amount of air that is being inhaled and exhaled. The signs of patients with narcolepsy that this test can reveal include falling asleep quickly, entering rapid eye movement (REM) sleep soon after falling asleep, and waking up often during the night.

Multiple Sleep Latency Test

The Multiple Sleep Latency Test, or MLST, is also called a nap study and is usually performed the day following the PSG test. A MLST can help measure how easy it is for the patient to fall asleep during the day. The patient is asked to take short naps roughly every two hours. Similarly to the PSG, the MLST uses sensors attached to the head to record eye movements, muscle tone, and brain activity. When performing the MLST, the doctor monitors whether the patient is able to fall asleep quickly, even though the patient has received a full night's sleep, and how quickly the patient enters REM sleep.

Physical Exam

This diagnosis method typically requires the doctor to do a complete physical exam, during which the doctor will check to see if you have signs of other possible causes for the symptoms they're exhibiting. Some of the possible causes include infections, certain thyroid diseases, drug or alcohol use, or other medical or sleep disorders.

Medical and Family Histories

When checking a medical and family history, the doctor will ask questions about daytime sleepiness and sleep attacks, sudden and temporary losses of muscle tone and control (cataplexy), vivid dreams while falling asleep or waking up (hallucinations), or an inability to move or speak while falling sleep or waking up (sleep paralysis). In addition the doctor will check whether anyone in the family has ever been diagnosed with narcolepsy, or whether they exhibit any of the same types of symptoms. This is important as a patient's chance of developing narcolepsy is much higher if a member of their family has also been diagnosed with narcolepsy.

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