Sleep Flashcards
What are the features of NREM sleep?
Reduced heart rate, blood pressure and tidal volumes
More NREM at beginning of the night
Synchronised, rhythmic EEG activity
Partial muscle relaxation of muscles
Reduced cerebral blood flow
What are the features of REM sleep?
Mostly at the end of the night
Cerebral blood flow increased
Atonic muscles
Narrative dreaming
What type of sleep is more important/deeper?
NREM sleep
Which type of sleep is similar to wakefulness?
REM sleep
What drugs might suppress REM sleep?
Tricyclics
What processes occur during NREM sleep that allow the cortex to recover?
Protein synthesis, cell division and growth
What processes occur during REM sleep?
Consolidation of memory
Maintains immunocompetence
Species with high metabolic rates have longer sleep times, suggesting importance in conserving energy
How does light train the body clock?
Uses retinal ganglion cells projecting to suprachiasmatic nucleus
What do parasomnias involve?
Involve abnormal movements, behaviors, emotions, perceptions, and dreams that occur while falling asleep, sleeping, between sleep stages, or during arousal from sleep.
What is parasomnia?
A disorder characterized by abnormal or unusual behaviour of the nervous system during sleep
What are some examples of NREM parasomnias?
Non-dreaming
Sleep walking
Sleep terrors
Sleep paralysis
Confusional arousal
Bruxism
Restless legs
What disease are REM sleep parasomnias associated with?
Parkinsons
What part of the night do REM parasomnias occur in??
Latter 1/3
What is narcolepsy?
Chronic neurological disorder involving the loss of the brain’s ability to regulate sleep-wake cycles normally
How does narcolepsy present?
Excessive daytime sleepiness - involuntary somnolence during eating/talking which may be severe, and impossible to resist
Cataplexy
Hypnagogic hallucinations
Sleep paralysis
What is cataplexy?
A medical condition in which strong emotion or laughter causes a person to suffer sudden physical collapse though remaining conscious
In what percentage of people with narcolepsy is cataplexy a feature?
70%
What measurement may be low in narcolepsy?
Hypocretin assessed with lumbar puncture
How is narcolepsy investigated?
Multiple sleep latency test
Hypocretin level – low
Overnight polysomnography
What are the two peaks of age of onset of narcolepsy?
Age 15
Age 36
How is a multiple sleep latency test carried out?
4 twenty five minute naps are scheduled about two hours apart
Record of EEG, muscle activity and eye movement recorded
Measures time from the start of a daytime nap to the first signs of sleep (sleep latency)
