Studied by 1 personDescribe the physiological mechanism of sleep + waking + consider the role of circadian rhythms and biological clock
Why do we sleep?
Restoration (immune, wound healing) Hormone production (GH, prolactin/cortisol, TSH) Waste clearance (e.g. beta-amyloid) Memory Mental health and behaviour
What nucleus is the caradian pacemaker?
Suprachiasmatic nucleus
What are the important hormones of sleep?
Orexin- epilepsy Melatonin- sleep GABA- sedation Adenosine
What does this EEG show?
Highly aroused, stimulated
What does this EEG show?
Alert, attentive
What does this EEG show?
Relaxed, eyes closed
What does this EEG show?
Light sleep/very drowsy (and in kids?)
What does this EEG show?
Deep sleep (stage 3)
What are the stages of sleep?
Wakefulness N1, N2, N3 ( Non-REM stage) REM
What type of rhythm is found in wakefulness?
Alpha rhythm
What type of rhythm is found in N1?
Theta, slow eye movements
What type of rhythm is found in N2?
K complexes and sleep spindles
What type of rhythm is found in N3?
Delta
What type of rhythm is found in REM?
Wakelike EEG, EMG: low chin tone (paralysis), rapid eye movements
What % of sleep is N1?
5-10%
What % of sleep is N2?
45-50% (longest)
What % of sleep is N3?
15-25%
What % of sleep is REM?
20-25%
What hormones causes the pressure to sleep?
Adenosine
What hormones increases the most during sleep?
Melatonin. It sustains sleep
When does melatonin peak during sleep?
After 4 am of sleep
Why does caffeine reduce your ability to sleep?
Is a competitive inhibitor of adenosine. Eventually, the receptors will get saturated and reach a point when increase caffeine will do nothing. Does not affect melatonin.
What is chronotype?
Morning or night person
What is chronotype determined by?
genetics
Can chronotype change?
Yes, changes by age
What decides our circadian rhythm?
Clock genes
What are zeitgebers?
An environmental agent or event. A cue in the regulation of the body’s circadian rhythm.
Give an example of zeitgebers.
Natural day light. During winter less light therefore feel sleepier during the day.
What are non-photic zeitgebers?
non-environmental factors that effect sleep.
What are examples of non-photic zeitgebers?
Jet lack – change of down zones suddenly Temperature- too clod, hot Exercise at night stops sleeping. During day it can help with sleeping during the day Stress Eating- hungry (can’t sleep) + same if too full
What are good sleep hygiene practices?
Go to bed and get up around the same time each day.
Relaxing routine.- tech giving wake sense
No big meals before bed.
Exercise.
Bed is for sleeping only.
What are the 2 types of insomnia?
Primary and secondary
What is primary insomnia?
Having insomnia alone (isolates). It is not a symptoms of other illnesses
What is secondary insomnia?
Due to co-morbid psychiatric or medical disorder or medication.
Does the treatment of the primary illness always resolve secondary insomnia?
No
What % of insomnia cases are primary?
25
How is insomnia diagnosed?
Decrease in sleep quantity/quality, 3 times a week for more than 3 months.
What is the prevalence of insomnia?
10-15% of population
What is the first line of treatment for insomnia?
Sleep hygiene strategies- not watching tv in bed, clearing mind
What is short-term treatment for insomnia?
Medication (less than a week)
Why is medication a short-term treatment for insomnia?
Tolerance, very addictive
When is medication given for insomnia?
Good for a person who can't go to sleep at all, gives them the pattern to go to sleep. Can break the cycle.
Someone with severe relapse (psychotic) for a mental disorder/ manic episode which can be revered by sleep is given medications short term to help.
What medication is given long term to treat insomnia?
Melatonin- long term not over the counter (in America it is OTC)
What type of insomnia does CBT treat?
Primary
What is obstructive sleep apnea?
Firstly snoring, briefly stop breathing then wake up quickly. N3 to N1 quickly. Very tired during the day.
What is the treatment of OSA?
CPAP Reduces risk of stroke and MIs Reduces fatigue
What is restless leg syndrome?
Constant urge to move legs at rest, temporarily relieved with activity. Tingling in the legs.
What is Periodic Limb Movements of Sleep?
Repetitive involuntary movements of limbs (usually legs) during sleep.
Are “Hypnic jerks” pathological?
normal phenomenon.
What are the 2 categories of parasomnias?
REM NREM
Example of REM parasomnias.
REM sleep behaviour disorder (Movement, such as kicking, punching, arm flailing or jumping from bed, in response to action-filled or violent dreams, such as being chased or defending yourself from an attack). People acting out their dreams. Nightmares.
Examples of NREM parasomnias.
Sleep walking
Sleep eating/drinking
Night terrors
What are night terrors?
Usually in young. Do not remember them at all but will wake up screaming. Not disturbing for the person.
What abnormality is found in REM parasomnias?
In normal REM you should be paralysed (but eyes) but in these disorders they are not so they start walking etc.
What are the 2 types of hypersomnia?
narcolepsy + Kleine-Levin
What is narcolepsy?
Excessive daytime sleepiness, involuntary sleep, cataplexy. Low orexin. (like going in and out of rem sleep)
What is Kleine-Levin?
hypersomnia (sleep too much), hyperphagia (too much eating), hypersexuality episodes. Frontal lobe issue.
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