Sleep

Question 1

what is sleep?

Answer 1

a readily reversible state of reduced responsiveness to, and interaction with, the environment

Question 2

what are the two types of sleep?

Answer 2

Non-REM, REM

Question 3

what is the definition of non-REM sleep?

Answer 3

Idling brain in a movable body

Question 4

what are the features of non-REM sleep?

Answer 4

slow, large amplitude

Question 5

what are the EEG features of non-REM sleep?

Answer 5

• Partial relaxation of muscles
• Temperature and energy consumption are lowered
• Increase in parasympathetic
• Some non-narrative images

Question 6

what are the 4 types of non-REM sleep?

Answer 6

N1, N2, N3, N4

Question 7

what is the features of N1 sleep?

Answer 7

between sleep and wakefulness, brain produces theta waves, hypnagogic hallucinations (hearing and seeing things that aren’t there, repetitive movements. Boat, Tetris effect, falling), only lasts a few mins

Question 8

what is the features of N2 sleep?

Answer 8

harder to awaken, more theta waves, sleep spindles (bursts of rhythmic brain activity – inhibit cognitive processes), K complexes (suppress cortical processes and help with memory processing), lasts 5-15 mins

Question 9

what is the features of N3 sleep?

Answer 9

slow wave sleep, delta waves

Question 10

what is the features of N4 sleep?

Answer 10

large EEG rhythms very difficult to wake up, sleep walking and talking

Question 11

what is the function of non-REM sleep?

Answer 11

protein synthesis, cell division and growth, body repair + restoration

Question 12

what is the definition of REM sleep?

Answer 12

active, hallucinating brain in a paralysed body

Question 13

what are the features of REM sleep?

Answer 13

• Fast, low voltage fluctuations EEG activity, fMRI shows increased brain activity

Question 14

what are the features of REM sleep?

Answer 14

Brain activity similar to wakefulness
Atonic muscles (total paralysis) - except diaphragm and extraocular muscles
Dominant control via sympathetic system
Narrative dreaming

Question 15

what does parasympathetic stimulation in Non-REM sleep cause?

Answer 15

reduced cerebral blood flow, reduced heart rate, blood pressure and tidal volumes

Question 16

what does sympathetic stimulation in REM sleep cause?

Answer 16

Cerebral blood flow increased, impaired thermal regulation, heart rate irregular

Question 17

what is the function of REM sleep?

Answer 17

consolidates memory, deletes unnecessary memory files, maintains immunocompetence, conserve energy in high metabolic species

Question 18

what is the order of a sleep cycle?

Answer 18

N1 → N2 → N3 → N2 → REM → N1 = Repeat

Question 19

how long is an average sleep cycle?

Answer 19

90mins

Question 20

what is the average split of REM to Non-REM?

Answer 20

75% NREM 25% REM

Question 21

what neurons are responsible for control of sleep?

Answer 21

diffuse modulatory neurotransmitter systems

Question 22

what brain stem modulators enhance REM sleep?

Answer 22

acetylcholine

Question 23

what controls the EEG rhythms of the brain?

Answer 23

Thalamus

Question 24

what is the pattern of sleep tendency?

Answer 24

2 peak

Question 25

how long is the circadian rthythym?

Answer 25

25 hours

Question 26

what is the cause of narcolepsy?

Answer 26

* CNS Pathology – trauma, stroke, tumours, infection, cysts, MS * Genetics – HLA * Sporadic

Question 27

what are the clinical features of narcolepsy?

Answer 27

``` daytime sleepiness cataplexy Hypnagogic hallucinations Sleep paralysis RBD ```

Question 28

how is narcolepsy diagnosed?

Answer 28

Overnight polysomnography Multiple sleep latency test Lumbar puncture - CSF hypocretin

Question 29

what is the pathophysiology of narcolepsy?

Answer 29

* Cholinergic hypersensitivity * Serotonin or noradrenaline pathway-specific dysfunction * Dopamine pathway dysfunction * CNS histamine deficiency * Hypocretin (orexin) pathway dysfunction

Question 30

what is the management of Adults with Narcolepsy?

Answer 30

o Sleep hygiene + lifestyle changes (non-pharmacological treatment) o CNS stimulants alone or in combination – modafinil, armodafinil, methylphenidate, dexamfetamine, sodium oxybate, methamphetamine

Question 31

what is the management of adults with cataplexy?

Answer 31

o Avoidance of triggers + sodium oxybate and/or antidepressants o Monoamine oxidase inhibitors

Question 32

what is the management of Children with narcolepsy?

Answer 32

o Sleep hygiene + lifestyle changes | o Modafinil or methylphenidate

Question 33

what is the management of Children with cataplexy?

Answer 33

o Avoidance of triggers + antidepressants – fluoxetine, venlafaxine, clomipramine