Sleep physiology, hyper somnolence, parasomnias Flashcards
Describe non-REM sleep
More at start of night
Synchronised, rhythmic EEG activity, partial relaxation of muscles, reduced cerebral blood flow
Reduced HR, blood pressure and tidal volumes
Some non-narrative images
Describe REM sleep
Mostly at end of night
EEG shows fast activity, similar to wakefulness
Atonic muscles (except diaphragm and extra ocular muscles
Cerebral blood flow increased, impaired thermoregulation
Narrative dreaming
Which part of sleep is essential?
Non-REM
What is REM sleep thought to be for?
Early brain development- substitute for wakefulness
Which drugs suppress REM
Tricyclic
What is non-REM sleep for?
Protein synthesis, cell division and growth
What does circadian rhythm regulate?
Sleep-wake, appetite, body temperature, hormone secretion, alertness
How long is a normal circadian rhythm?
25 hours
How does light entrain body clock?
Uses retinal ganglion cells projecting to suprachiasmatic nucleus. Non-rod, non-cone cell/
When does cell division peak?
Skin mitosis peaks during sleep, however time of day effect- also increases after meals
What are the side effects of sleep deprivation?
Irritable and suspicious
Visual illusions
Microsleeps and concentration lapses
About __% of RTAs attended by police are sleep related
10%
What is an appropriate amount of sleep?
7-7.5 hours
A mid afternoon nap is equivalent to __ minutes of sleep overnight
90
What are the non- REM parasomnias?
Non-dreaming Confusional arousals sleep walking Sleep terrors and paralysis Bruxism Restless legs and PMLS
When are REM parasomias often seen?
Preceding PD
Which type of sleep disorders show simpler behaviour?
REM parasomnias
What are the peaks of onset of narcolepsy?
age 15 and 36
What is the clinical presentation of narcolepsy?
Characterised by;
- Daytime sleepiness
- Cataplexy
- Hynagogic hallucinations
- Sleep paralysis
- RBD
What is daytime sleepiness?
Involuntary somnolence during eating/talking
May be severe, and impossible to resist
What is cataplexy?
Loss of muscle tone triggered by emotion
What are hypnagogic hallucinations?
Hallucinations occurring at sleep onset
What is sleep paralysis?
Unable to move upon falling asleep or awakening with retained consciousness
What is RBD
Sleep behaviour disorder -present in 7-36% of patients with narcolepsy
What are the investogations for narcolepsy?
Overnight polysomnography
Multiple sleep latency test
Lumbar puncture
What is involved in a multiple sleep latency test?
4 twenty five minute maps are scheduled out two hours apart
Record of EEG, muscle activity and eye movement recorded
Measures time from start of a daytime nap to the first signs of sleep (sleep latency)
Faster patient falls asleep the more tired they are
What is checked in lumbar puncture for narcolepsy?
CSF hypocretin levels, Low levels (less than 110pg/ml or 1/3 of the mean control value) are consistent with narcolepsy
