 Narcolepsy
is a chronic sleep disorder with no
known cause. The main characteristic
of narcolepsy is excessive and overwhelming
daytime sleepiness, even after adequate
nighttime sleep. A person with narcolepsy
is likely to become drowsy or to fall
asleep, often at inappropriate times
and places. Daytime sleep attacks may
occur with or without warning and may
be irresistible. These attacks can occur
repeatedly in a single day. Drowsiness
may persist for prolonged periods of
time. In addition, nighttime sleep may
be fragmented with frequent awakenings.
Daytime sleepiness, sleep paralysis,
and hypnagogic hallucinations can also
occur in people who do not have narcolepsy.
Three other classic
symptoms of narcolepsy, which may not
occur in all patients, are:
-
Cataplexy:
sudden episodes of loss of muscle
function, ranging from slight weakness
(such as limpness at the neck or
knees, sagging facial muscles, or
inability to speak clearly) to complete
body collapse. Attacks may be triggered
by sudden emotional reactions such
as laughter, anger, or fear and
may last from a few seconds to several
minutes. The person remains conscious
throughout the episode.
-
Sleep
paralysis: temporary inability
to talk or move when falling asleep
or waking up. It may last a few
seconds to minutes.
-
Hypnagogic
hallucinations: vivid,
often frightening, dream-like experiences
that occur while dozing or falling
asleep.
In most cases, the
first symptom of narcolepsy to appear
is excessive and overwhelming daytime
sleepiness. The other symptoms may begin
alone or in combination months or years
after the onset of the daytime sleep
attacks. There are wide variations in
the development, severity, and order
of appearance of cataplexy, sleep paralysis,
and hypnagogic hallucinations in individuals.
Only about 20 to 25 percent of people
with narcolepsy experience all four
symptoms. The excessive daytime sleepiness
generally persists throughout life,
but sleep paralysis and hypnagogic hallucinations
may not.
The symptoms of narcolepsy,
especially the excessive daytime sleepiness
and cataplexy, often become severe enough
to cause serious disruptions in a person's
social, personal, and professional lives
and severely limit activities.
Narcolepsy can occur in both men and women
at any age, although its symptoms are usually
first noticed in teenagers or young adults.
There is strong evidence that narcolepsy
may run in families; 8 to 12 percent of
people with narcolepsy have a close relative
with the disease.
Although it is estimated that narcolepsy
afflicts as many as 200,000 Americans,
fewer than 50,000 are diagnosed. It is
as widespread as Parkinson's disease or
multiple sclerosis and more prevalent
than cystic fibrosis, but it is less well
known. Narcolepsy is often mistaken for
depression, epilepsy, or the side effects
of medications.
Normally, when an individual is awake,
brain waves show a regular rhythm. When
a person first falls asleep, the brain
waves become slower and less regular.
This sleep state is called non-rapid eye
movement (NREM) sleep. After about an
hour and a half of NREM sleep, the brain
waves begin to show a more active pattern
again, even though the person is in deep
sleep. This sleep state, called rapid
eye movement (REM) sleep, is when dreaming
occurs.
In narcolepsy, the order and length of
NREM and REM sleep periods are disturbed,
with REM sleep occurring at sleep onset
instead of after a period of NREM sleep.
Thus, narcolepsy is a disorder in which
REM sleep appears at an abnormal time.
Also, some of the aspects of REM sleep
that normally occur only during sleep--lack
of muscle tone, sleep paralysis, and vivid
dreams--occur at other times in people
with narcolepsy. For example, the lack
of muscle tone can occur during wakefulness
in a cataplexy episode. Sleep paralysis
and vivid dreams can occur while falling
asleep or waking up.
You should be checked for narcolepsy
if:
- You often feel excessively and overwhelmingly
sleepy during the day, even after having
had a full night's sleep;
-
You fall asleep
when you do not intend to, such as
while having dinner, talking, driving,
or working;
-
You collapse suddenly
or your neck muscles feel too weak
to hold up your head when you laugh
or become angry, surprised, or shocked;
-
You find yourself
briefly unable to talk or move while
falling asleep or waking up
Diagnosis is relatively easy when all
the symptoms of narcolepsy are present.
But if the sleep attacks are isolated
and cataplexy is mild or absent, diagnosis
is more difficult, Two tests that are
commonly used in diagnosing narcolepsy
are the polysomnogram and the multiple
sleep latency tests. A sleep specialist
usually performs these tests. The fpolysomnogram
involves continuous recording of sleep
brain waves and a number of nerve and
muscle functions during nighttime sleep.
When tested, people with narcolepsy
fall asleep rapidly, enter REM sleep
early, and may awaken often during the
night. The polysomnogram also helps
to detect other possible sleep disorders
that could cause daytime sleepiness.
For the multiple sleep latency test,
a person is given a chance to sleep
every 2 hours during normal wake times.
Observations are made of the time taken
to reach various stages of sleep. This
testmeasures the degree of daytime sleepiness
and also detects how soon REM sleep
begins. Again, people with narcolepsy
fall asleep rapidly and enter REM sleep
early.
Although there is no cure for narcolepsy,
treatment options are available to help
reduce the various symptoms. Treatment
is individualized depending on the severity
of the symptoms, and it may take weeks
or months for an optimal regimen to
be worked out. Complete control of sleepiness
and cataplexy is rarely possible. Treatment
is primarily by medications, but lifestyle
changes are also important. The main
treatment of excessive daytime sleepiness
in narcolepsy is with a group of drugs
called central nervous system stimulants.
For cataplexy and other REM-sleep symptoms,
antidepressant medications and other
drugs that suppress REM sleep are prescribed.
Caffeine and over-the-counter drugs
have not been shown to be effective
and are not recommended.
In addition to drug therapy, an important
part of treatment is scheduling short
naps (10 to 15 minutes) two to three
times per day to help control excessive
daytime sleepiness and help the person
stay as alert as possible. Daytime naps
are not a replacement for nighttime
sleep. Ongoing communication among the
physician, the person with narcolepsy,
and family members about the response
to treatment is necessary to achieve
and maintain the best control.
Understanding Narcolepsy
Studies supported by the National Institutes
of Health (NIH) are trying to increase
understanding of what causes narcolepsy
and improve physicians' ability to detect
and treat the disease. Scientists are
studying narcolepsy patients and families,
looking for clues to the causes, course,
and effective treatment of this sleep
disorder. Recent discovery of families
of dogs that are naturally afflicted
with narcolepsy has been of great help
in these studies. Some of the specific
questions being addressed in NIH-supported
studies are the nature of genetic and
environmental factors that might combine
to cause narcolepsy and the immunological,
biochemical, physiological, and neuromuscular
disturbances associated with narcolepsy.
Scientists are also working to better
understand sleep mechanisms and the
physical and psychological effects of
sleep deprivation and to develop better
ways of measuring sleepiness and cataplexy.
Coping with Narcolepsy
Learning as much about narcolepsy as
possible and finding a support system
can help patients and families deal
with the practical and emotional effects
of the disease such as, possible occupational
limitations and situations that might
cause injury. A variety of educational
and other materials are available from
sleep medicine or narcolepsy organizations.
Support groups exist to help persons
with narcolepsy and their families.
Individuals with narcolepsy, their families,
friends, and potential employers should
know that:
-
Narcolepsy is
a life-long condition that requires
continuous medication.
-
Although there
is not a cure for narcolepsy at present,
several medications can help reduce
its symptoms.
-
People with narcolepsy
can lead productive lives if they
are provided with proper medical care.
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