00:01
In terms of epidemiology, narcolepsy type 1 and 2 are
uncommon with the prevalence of 25-50/100,000. There is an
equal predominance
in men and women for narcolepsy type 1 and we typically see
this occurring and
beginning in the early teenage years in the 20s. In terms of
clinical features, the
common feature in these patients is daytime sleepiness. This
is the most common
symptom of all types of narcolepsy. Patients may have
sleeping at inappropriate
times as opposed to excessive sleeping, they just sleep at
times that is
inappropriate. They may have sleep attacks where they fall
asleep with no warning
sign, lasting less than 30 minutes and usually they wake up
well rested in the
morning, but again have these sleep attacks occurring during
the day. Cataplexy
can be seen in 60-70% of patients. Again, these are these
emotionally triggered
episodes where patients transiently lose muscle tone and
become weak. It may be
triggered by intense laughing or anger or a startle or loud
noise. Patients lose tone
often beginning in the face and this may progress to a full
drop attack where the
patient is on the ground, atonic, extremely weak for a short
period of minutes. The
patient is conscious, this usually last around 2 minutes,
and 60% of patients will
present within 5 years of onset of the disease with symptoms
of cataplexy.
01:36
How about hypnagogic hallucinations? These are auditory or
sometimes tactile
hallucinations that occur as patients are going to sleep.
Patients may describe
frightening; visual, tactile and sometimes auditory
hallucinations that occur again
while falling asleep, not while waking up. Sleep paralysis
is quite uncommon,
less than 5% of patients, but extremely burdensome and
worrisome for patients.
02:05
Patients will describe upon awakening that they are awake
and fully conscious but
unable to move their body, typically lasting less than 2
minutes and this results
from disconnection between the brain circuits that allow the
brain to awake and
turn the brain on and then those that return muscle tone
from REM sleep. And that
disconnection between those 2 systems results in wakefulness
of consciousness but
inability to return tone for those first couple of minutes
upon awakening.