Narcolepsy
An article in the Scientific American, by Jerome M. Siegel, focused on
a
dangerous sleeping disorder called Narcolepsy. A Narcoleptic has Symptoms
such
as cataplexy, which is the loss of skeletal muscle tone, and always
feeling
sleepy during daytime hours. The people suffering from this disorder
tend to
feel as if they hadn't gone to sleep for 48 hours. In addition, they
sleep
poorly at night. Laughter, embarrassment, sudden anger, social
interactions with
strangers, and sexual intercourse may trigger a cataplectic
attack. A
Narcoleptic may even fall asleep at the most dangerous times.
For example,
driving a car with this untreated disorder puts a person at high
risk of an
automobile accident. The disorder makes it difficult for them to
focus on
specific things, such as schoolwork or work in the workplace. Sleep
paralysis
and hypnagognic hallucinations are among two other symptoms of
narcolepsy. Sleep
paralysis is an ability to move when you fall asleep or
awaken. This occurs
daily. On the other hand, hypnagogic hallucinations are
dreamlike experiences
during waking that sometimes incorporate elements of
the environment. These
symptoms occur when narcoleptics are most sleepy. In
addition, not every person
suffers from the symptoms the same way. Also, this
article pointed out that
Narcolepsy affects between one and one thousand
and one and two thousand people
in the U.S. In contrast, one in 600 in Japan
to one in 500,000 in Israel. It
also stated that the environment and ethnic
backgrounds are the reason for the
number differences of these countries. The
first signs of Narcolepsy appear in
the teens or 20's. The symptoms do get
worse after a few years and then they
plateau. The causes or Narcolepsy is
linked to a disruption of the sleep control
mechanism in our brain. Our sleep
cycle normally has two stages, Rapid-Eye
movement Sleep (REM), and Non-Rapid
Eye Movement Sleep (NREM). When we’re
experiencing NREM sleep, our muscles
are relaxed, breathing is normal, the
cerebral cortex generates high-voltage
waves and the energy consumed by the
brain is minimized. In contrast, in REM
sleep, breathing and heart rate are
irregular, rapid eye movements occur; the
cortex generates fast, irregular, low
voltage waves. Non-Narcoleptics tend to
begin to sleep with NREM sleep. After 90
minutes or so, they're in REM sleep.
When this happens, they experience loss of
muscle tone and dreamlike
hallucinations that usually occur during REM sleep.
Researchers stated
that being sleepy is normal, but it’s the large amount of
sleep in
Narcoleptics that’s very abnormal. In the early 1970's, advanced
research in
Narcolepsy began. Researchers discovered that some dogs showed that
they had
very similar symptoms to human narcoleptics. William C. Demit of
Stanford
University stated that the disease in the dogs was inherited by both
the
mother and father to their offspring. In the 1940's, Horace W. Magnoun
of
Northwestern University discovered when he electrically stimulated the
medulla
(part of the brain stem) the muscle tone disappeared. He didn't
connect his
studies to sleep. The studies in animals show us that the main
function of the
muscle-tone control system in the medulla suppresses muscle
activity in REM
sleep. In addition, it regulates the level of muscle tone in
waking. This part
doesn’t work when the animals are moving. This explains the
notion of when we
try to relax or "turn off" our muscles; we are actually
trying to "turn
on" this specific section of the brain. REM sleep is the only
time when normal
individuals lose all muscle tone. Another study by Frank Wu
indicated that there
was another group of nerve cells in the brainstem called
the Locus Coeruleus.
The locus coeruleus also plays a role in REM sleep
and narcolepsy. It releases a
neurotransmitter called norepinephrine, which
communicates with another neurons.
Both these nerve cells are active in
animals in waking, but inactive when
they’re in REM sleep. In REM sleep the
reduced amount of motor neurons
prevents them from moving or responding to
their dreams. In cataplexy, the same
reduction prevents the motor neurons
from responding to a narcoleptics attempt
to move. Researchers also concluded
that unknown agents in the environment may
cause an autoimmune reaction that
ends up damaging neurons in the brain that
control arousal and muscle tone.
After narcoleptic symptoms occur, the patients
don’t get any worse or any
better. This tells us that the damage might show up
for a short time; during
the time the patients first develop the signs of this
sleep disorder. The
brains supports cells later removed the damaged cells left
over from this
sleeping disorder in the brain of the patient as they aged and
before most
patients died. Siegel also supported his hypothesis by stating that
the
degeneration in dogs was in the amygdala. The amygdala is a brain
structure
involved in emotion and inducing sleep. The damage to the amygdala
can cause the
symptoms of narcolepsy by inappropriately activating brain-stem
circuits that
are undamaged. At this time, patients are given stimulants such
as Ritalin and
Cylert or amphetamines. Their purpose is to reduce the
sleepiness experienced by
the narcoleptics. These drugs only are affective
for a short period of time and
cause side affects such as agitation, dry
mouth, and anxiety. Doctors also
prescribe monoamine oxidase inhibitors. The
purpose is to prevent cataplectic
attacks of narcolepsy. They’re still hoping
for new treatments that will
improve the treatment of this disease. So far,
the results of the research look
very promising.