Sleep

Describe 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.