Sleep Physiology, Hypersomnolence, Parasomnias Flashcards
what is sleep?
normal, recurring, reversible state where there is loss of ability to respond to external environment
what makes sleep not a conscious state?
not fully aware of self and environment
what makes sleep not an unconscious state?
can respond when stimulated
when do you have more non REM sleep?
start of night (3/4 of sleep for young adults is NREM)
what occurs to the body during non REM sleep?
synchronised, rhythmic EEG activity
partial muscle relaxation
reduced cerebral blood flow
what is heart rate during non REM sleep?
reduced heart rate
do you dream during non REM sleep?
yes - get some non-narrative images
when do you have more REM sleep?
end of night
what happens to body during REM sleep?
EEG shows fast activity
fMRI shows increased brain activity - similar to awake
atonic muscles (except diaphragm and extraocular muscles)
increased cerebral blood flow
impaired thermal regulation
do you dream during REM sleep?
yes - narrative dreaming
what type of sleep is more important?
non REM sleep (deep sleep)
why is non REM sleep more important?
allows cortex to recover after a busy day
what is the main role of REM sleep?
early brain development in children
what type of drugs suppress REM sleep?
tricyclics
how many hours per day do neonates spend seeping?
what kind of sleep?
16
50% REM sleep, shorter cycles
what is the trend of REM sleep during 1st decade?
percentage REM sleep falls
REM latency increases
what kind of sleep habits do elderly experience?
increased awakenings
reduced REM latency and total sleep time
daytime napping
what are the three critical processes of sleep onset?
homeostatic response - regulated need for sleep
emotional response - brain has to be ready to go to bed
circadian rhythm - body clock
do adolescents have an advanced or delayed sleep pattern?
delayed
do elderly have advanced or delayed sleep pattern?
advanced
how long does normal circadian rhythm last?
25 hours
how does light entrain body clock?
using retinal ganglion cells (non-rod and non-cone cells) projecting to suprachiasmatic nucleus
(why dark room = cant get up in morning)
can the cortex rest when awake?
no - only during sleep
when awake it stays in “quiet readiness”
most effects of sleep deprivation and prefrontal - what are these?
no psychoses but become irritable and suspicious
visual illusions
microsleeps and concentration lapses
what time is the two peaks of drowsiness?
what also occurs at this time?
4am and 2pm
peak of number of sleep related crashes
about 10% of RTAs attended by police are sleep related (most acutely deprived), in what kind of road is this number doubled?
non-urban roads
what is most likely cause of accidental death at work in UK just now?
truck driver falling asleep at wheel
what do most studies suggest is an acceptable amount of sleep?
7 - 7.5 hours
donald trump thinks he only needs 3 hours sleep a night - why is he wrong about this? (and everything else he does)
he has lost perception of how sleepy they are - homeostatic response is dysfunctioning
a mid afternoon nap of 15 minutes is equivalent to how many minutes of overnight sleep?
90 mins
what occurs during REM parasomnia?
dreaming, much simpler behaviour, usually latter third of night
what disease does REM parasomnias often precede?
parkinsons (about 38% of those with REM parasomnias get parkinsons)
what occurs during non-REM sleep parasomnias?
non dreaming confusional arousals sleep walking sleep terrors (crying or screaming) bruxism restless legs and PLMS possible dissociation
what is the incidence of narcolepsy in UK?
0.04%
where are the two peaks of age of narcolepsy onset?
15 and 36
what 5 things characterise narcolepsy?
daytime sleepiness - inappropriate times, during eating / talking
cataplexy - loss of muscle tone, triggered by emotion
hypnagogic hallucinations - hallucinations at sleep onset
sleep paralyses - unable to move on falling sleep or awakening with retained consciousness
RBD
what investigations take place in narcolepsy?
overnight polysomnography
multiple sleep latency test
lumbar puncture
how is a multiple sleep latency test carried out?
4 twenty five minute naps are scheduled about 2 hours apart
record of EEG, muscle activity and eye movement recorded
measures time from the start of daytime nap to the first signs of sleep (sleep latency)
patients falls asleep faster if they are sleepier
what is checked during a lumbar puncture for narcolepsy?
CSF hypocretin levels
low (<110pg/ml or 1/3 of mean control value) = narcolepsy
are you able to drive with narcolepsy?
yes but cease driving on diagnosis until control is achieved
permanent exclusion from group 2
what is REM sleep behaviour disorder?
paralysis that normally occurs during REM sleep is incomplete or absent, allowing the person to act out dreams dreams
characterized by the acting out of dreams that are vivid, intense, and violent
what is example of REM parasomnia?
nightmares
sleep paralysis
REM sleep behaviour disorder
