Narcolepsy
Narcolepsy's main symptom is excessive
and overwhelming daytime
sleepiness, even after adequate nighttime sleep. In addition,
nighttime
sleep may be fragmented by frequent awakenings.
People who
have narcolepsy often fall asleep at inappropriate times and
places.
Although television sitcoms occasionally feature these individuals
to generate a few laughs, narcolepsy is no laughing matter.
People
who have narcolepsy experience daytime "sleep attacks"
that last
from seconds to more than one-half hour, can occur without
warning, and may cause injury. These embarrassing sleep spells can
also make it difficult to work and to maintain normal personal or
social relationships.
With narcolepsy, the usually sharp distinctions
between being asleep
and awake are blurred. Also, people who have narcolepsy tend
to
fall directly into dream-filled REM sleep, rather than enter REM
sleep gradually after passing through the non-REM sleep stages first.
In addition to overwhelming daytime sleepiness,
narcolepsy has
three other commonly associated symptoms, but these may not
occur in all people:
- Sudden muscle weakness (cataplexy).
This weakness is similar
to the paralysis that normally occurs during REM sleep, but it
lasts a few seconds to minutes while an individual is awake.
Cataplexy tends to be triggered by sudden emotional reactions,
such as anger, surprise, fear, or laughter. The weakness may
show up as limpness at the neck, buckling of the knees, or
sagging facial muscles affecting speech, or it may cause a
complete body collapse.
- Sleep paralysis. People who have
narcolepsy may experience a
temporary inability to talk or move when falling asleep or
waking up, as if they were glued to their beds.
- Vivid (hypnogogic) dreams. These
dreams tend to surface
when people who have narcolepsy first fall asleep. The dreams
are so lifelike that they can be confused with reality.
Experts estimate that as many as
350,000 Americans have narcolepsy,
but fewer than 50,000 are diagnosed. The disorder is as
widespread as
Parkinson's disease or multiple sclerosis, and more prevalent
than
cystic fibrosis, but it is l ess well known.
Narcolepsy is often mistaken
for depression, epilepsy, or the side effects of medicines.
Narcolepsy can be difficult to diagnose in people who have only
the symptom of excessive daytime sleepiness.
It is usually diagnosed
with the aid of an overnight sleep recording (PSG).
The test
reveals signs of narcolepsy-the tendency to fall asleep rapidly and
enter REM sleep early, even during brief naps.
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