Sleep Flashcards
What is sleep?
A normal, recurring, reversible state
When do you enter NREM sleeo?
Start of night; 3/4 of sleep for young adults is NREM
What is NREM sleep?
Synchronised, rhythmic EEG activity, partial muscle realaxation, reduced cerebral blood flow, reduced HR, BP and tidal volumes
Do you dream in NREM sleep?
Yes; non-narrative
Wake up with a strong emotion but can’t quite remember what the dream was aobtu
When do you enter REM sleep?
End of night
What is REM sleep?
EEG shows fast activitiy, fMRI shows increased brain activity Atonic muscles (except diaphragm and extraocular muscles), cerebral blood flow increased, impaired thermal regulation
Do you dream in REM sleep?
Yes; narrative dreaming. Muscles paralysed so you don’t act out dreams
Which part of sleep is most important?
Deep sleep; only part of lost sleep regained after sleep loss
Allows the cortex to recover after a busy day
What is the function of REM sleep?
Early brain development; substitute for wakefullness
Do you sleep less or more as you get older, and what type of sleep do you lose?
Less
REM sleep falls, REM latency increases
What are the 3 mechanisms that control sleep?
Homeostatic
Emotional
Circadian rhythm
What is the circadian rhythm important for?
Sleep-wake
Appetite
Hormone secretion
What biological processes occur during NREM sleep?
Protein synthesis
Cell division and growth
What biological processes occur during REM sleep?
Consolidates memory
Deletes unnecessary memory files
Maintains immunocompetence
When are the 2 peaks in sleepiness?
4am
2pm
How many hours does the normal circadian rhythm last?
25 hours
What is the impact of light on circadian rhythms?
Non-rod and non-cone cells project to suprachiasmatic nucleus to reset the body clock every morning
What occurs in sleep deprivation?
Irritable and suspicious
Visual illusions
Microsleeps and concentration lapses
What can you still do well even in sleep deprivation?
Prefrontal;
Old and well rehearsed tasks
Routine behaviour
Logic tasks
What tasks are not performed well in acute and chronic sleep deprivation?
Understanding complex situations and ignoring irrelevancies Assessing risks and consequences Dealing with the unexpected Tracking events Updating strategies Communicating well Showing lateral thought and innovation
How much sleep do we need?
7-7.5hrs a night
A mid afternoon nap of 15 mins is equivalent to 90 mins overnight
What are the different types of parasomnias?
NREM Non-dreaming Confusional arousals Sleep walking Sleep terrors and paralysis Bruxism (teeth grinding) Restless legs and PLMS Complex dissociation
When will REM parasomnias manifest?
Latter 1/3rd of the night
Which condition is very closely associated with REM parasomnias?
Parkinson’s disease
What is the presentation of narcolepsy?
Daytime sleepiness Cataplexy Hypnagogic hallucinations Sleep paralysis RBD
What is cataplexy?
Loss of muscle tone triggered by strong emotion
What are hypnagogic hallucinations?
Hallucinations occurring at sleep onset
What is sleep paralysis?
Inability to move upon falling asleep or awakening with retained consciousness
How is narcolepsy investigated?
Overnight polysomnography
MSLT; assess how quickly someone falls asleep and enters REM sleep
LP; CSF hypocretin levels with low levels consistent with narcolepsy
What is insomnia?
Psychophysiological concept
Alertness around sleep
