Sleep Flashcards
What is sleep?
Normal, recurring, reversible state
What is lost during sleep?
The ability to respond to the external environment
Describe how sleep is both not conscious and not unconscious.
Non conscious - not able to respond to self and external environment
Not unconscious - as can respond when stimulated
When does NON-REM sleep occur?
At the start of the night
What proportion of sleep for young adults is NON-REM?
3/4
What is EEG activity like during NON-REM sleep?
Synchronised
Rhythmic
What happens to muscles during NON-REM?
They are partially relaxed
What happens to cerebral blood flow during NON-REM sleep?
REDUCED
What are dreams like during NON-REM sleep?
Some non-narrative images
When does REM sleep occur?
At the end of the night
What does an EEG show during REM sleep?
FAST activity
What does an MRI during REM sleep show?
Increased brain activity
What are the EEG and MRI findings during REM sleep similar to?
Wakefulness
What happens to muscles during REM sleep?
They become ATONIC, except some
What muscles do not become ATONIC during REM sleep?
Respiratory
Extra-ocular
What does REM stand for?
Rapid Eye Movement
What happens to thermal regulation during REM sleep?
It is impaired
What type of dreaming occurs in REM sleep?
Narrative
Deep sleep is _______ sleep
ESSENTIAL
What type of sleep is regained after sleep loss?
DEEP
Why is deep sleep important?
It allows the cortex to recover after a busy day
What is the main importance for REM sleep?
For early brain development - substitute stimulation for wakefulness
REM sleep is dispensable
TRUE
What term is used to describe REM sleep?
Non-wakefullness
Not sleep
What common drugs suppress REM sleep?
Tricyclics
Describe the sleeping patterns of neonates.
Spend 16 hours per day asleep – 50% REM sleep, have shorter cycles
Describe what happens to REM sleep after the first decade.
- % REM sleep falls.
* REM latency increases
Outline what happens to sleep in the elderly.
- Increased awakenings
- Reduced REM latency
- Reduced total sleep time and daytime napping
What controls sleep?
Biology and physiology, NOT psychology
What is circadian rhythm important for?
- Appetite
- Sleep-awake
- Hormones
Children sleep later and waken later
FALSE
- sleep earlier and waken earlier
Adolescents have a _____ sleep pattern
DELAYED
Elderly have an ____ sleep pattern
ADVANCED
Give examples of human processes controlled by circadian rhythm.
- Sleep-awake
- Appetite
- Body temp
- Hormone secretions
- Alertness
How long does normal circadian rhythm last?
25 hours
What entrains the body clock?
LIGHT
Describe how light controls the body clock.
RETINAL GANGLION CELLS, projecting to SUPRACHIASMATIC NUCLEUS
What is NON-REM sleep important for?
- Cell division and growth
* Protein synthesis
What is REM sleep important for?
- Consolidation of memories
- Deletion of unnecessary memory files
- Maintenance of immunocompetence
Species with high metabolic rates have longer sleep times. What does this suggest?
Importance in conserving energy
Sleep is related to ___ hormone release
GROWTH
Sleep helps with?
Tissue repair
What happens to cell division during sleep?
PEAKS
- skin mitosis peaks during sleep
- however, time of day effect, increases after meals
Describe the cortex and rest.
The cortex can only rest when fully asleep
Until, it is in ‘quiet readiness’
What is the relationship between cortices and sleep?
More complex cortices need more sleep
Most effects of sleep deprivation affect what part of the cortex?
PRE-FRONTAL
What are the problems associated with lack of sleep and the pre-frontal cortex?
- become irritable and suspicious, but no ‘psychoses.’
- visual illusions.
- microsleeps and concentration lapses.
What does sleep deprivation, affecting pre-frontal function NOT affect?
- routine
- old, well rehearsed tasks
- logic tasks
What does sleep deprivation affecting the pre-frontal lobe do?
Impairs alterness
How much sleep do we need a night?
7/7.5 hours
What is a 15 minute nap equivalent to?
90 minutes during the night
What is a parasomnia?
A disorder characterized by abnormal or unusual behaviour of the nervous system during sleep
Describe NON-REM parasomnias.
- Non-dreaming.
- Confusional arousals.
- Sleep walking.
- Sleep terrors and paralysis.
- Bruxism. (grinding teeth)
- Restless legs + PLMS (periodic limb movements of sleep).
- Often complex behaviours – possible dissociation
What is bruxism?
Grinding teeth
90% of patients with what condition have REM parasomnias?
Parksinson’s
Describe REM parasomnias.
- Dreaming.
* Much simpler behavior (than NREM).
At what part of the night do REM parasomnias usually occur?
Later 1/3rd of the night
What is Narcolepsy?
A condition characterized by an extreme tendency to fall asleep whenever in relaxing surroundings
At what ages does narcolepsy peak?
15 and 36
Often patients with REM sleep problems have narcolepsy
TRUE
Describe the clinical presentation of Narcolepsy.
- Daytime sleepiness
- Cataplexy
- Hypnagogic Hallucinations
- Sleep paralysis
What is cataplexy?
Loss of muscle tone triggered by emotion
What are Hypnagogic Hallucinations?
Hallucinations occurring at sleep onset
What Ix’s should be done for suspected Narcolepsy?
- Overnight polysomnography
- Multiple sleep latency test
- LP (not routine anymore)
Describe the multiple sleep latency test.
4 x 25 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)
Faster patient falls asleep faster if they are sleepier
Describe the LP findings that show Narcolepsy.
Low hypocretin levels (<110pg/ml or 1/3rd of the mean control value)
