Narcolepsy

Narcolepsy is a neurologic disorder which primarily results in excessive daytime sleepiness and impaired daily functioning.  Despite getting an adequate number of hours of sleep and feeling refreshed following each sleeping episode, individuals with narcolepsy often feel the overwhelming urge or desire to sleep during the day and often take naps to temporarily relieve this tendency to fall asleep.  Individuals with narcolepsy characteristically can fall asleep within minutes, unlike normal individuals which take at least 10-20 minutes to fall asleep.  Narcolepsy is not a rare condition, as it may be found in as many as 1 in every 2000 people.  The cause of narcolepsy is unknown.   The disease usually starts in individuals between the age of 15 and 25 years of age, but can first appear in individuals between 35 and 45 years of age, especially in women near menopause. 

In addition to having symptoms of excessive daytime sleepiness, there are other symptoms which are less commonly seen in individuals with narcolepsy.  These include sleep paralysis, cataplexy, and hypnagogic hallucinations.  Sleep paralysis is a temporary state in which the narcoleptic does not have the ability to move, speak, or breathe deeply, and these episodes occur when the narcoleptic is either beginning to fall asleep or upon awakening from sleep.  These episodes may last only seconds or for many minutes.  Sleep paralysis may be a frightening experience to the narcoleptic, but is in no way life threatening or physically disabling. Cataplexy is the abrupt, reversible loss of muscle strength which may be limited to the face and neck or involve the arms and legs, resulting in a fall.  Cataplexy typically occurs when  a narcoleptic is emotionally excited such as with laughing, fear, anger, or sudden anxiety.  Although cataplexy can be mistaken for a seizure, it is very different in that for cataplexy there is no loss of consciousness and the narcoleptic is aware of the attack.  During a seizure, on the other hand, patients are not aware and often lose consciousness. Lastly, Hypnagogic hallucinations are vivid dreams that occur upon awakening from sleep, and may be visual, auditory, or olfactory (smell) type.  People may describe these as  very disturbing dreams, sometimes difficult to distinguish from reality.    

The diagnosis of narcolepsy requires two kinds of sleep studies.  The first is a nighttime sleep study which records the total amount of sleep as well as the quality of sleep.  This is important to make sure other sleep disorders are not present, such as sleep apnea or periodic limb movements.  Following the nighttime study, a series of daytime nap studies are then performed to measures how long it takes one to fall asleep.  This series of naps is the second study called a multiple sleep latency test, or MSLT.  Not only does it measure the time it takes an individual to fall asleep, but also whether rapid eye movement sleep (REM or Dream sleep) occurs during any of these naps.  Dreaming should not occur during daytime naps, but occurs in narcoleptic patients.  If dreaming occurs in at least two nap trials during the MSLT, then narcolepsy is confirmed when the remaining history supports this diagnosis.
 
Treatment of narcolepsy is sometimes difficult, but in most cases medications are very effective.  Educating the narcoleptic about the hazards of having the sudden urge to sleep or lose muscle tone is the most important aspect of dealing with this disease.  Here are some important tips:

1.  As much as possible, attempt to go to bed and awaken the same time every day.

2.  Take regularly scheduled naps during the day, especially prior to planned activities requiring an alert state such as driving and work.

3. Assure a well rested, non-sleepy state while driving or performing activities in which sleep onset would be dangerous.

4. Avoid swimming alone, climbing ladders or other situations in which cataplexy would be dangerous.

5.  Avoid sedatives, including over the counter medications such as cold and allergy remedies which may cause drowsiness.

6.  Avoid jobs and social stresses that are disruptive to consistent sleep patterns.

In addition to these basic measures, patients usually require medications to help control the urge to sleep and improve daytime alertness.  These are usually central nervous system stimulants.  Alternative medications are used for symptoms of cataplexy, sleep paralysis, or hypnogogic hallucinations.

An additional aspect of narcolepsy treatment is evaluating for depression.  It is relatively common for narcoleptic patients to be experiencing depression.  In fact, the diagnosis of narcolepsy may be mistaken for depression.  Psychological counseling is often of benefit for narcoleptic patients.

As a final note, it is important to realize that there are many conditions other than narcolepsy which cause excessive daytime sleepiness.  If excessive daytime sleepiness is a concern, then it may be helpful to discuss this problem with a physician experienced in sleep medicine.  It is important to determine whether excessive daytime sleepiness is due to narcolepsy or another treatable medical condition.