lecture 12 sleep disorders

Question 1

What is sleep paralysis

What is it associated with

Answer 1

temporary period of paralysis (hypnogogic or hypnopompic)

associated with hallucinations

associated with REM at sleep onset

able to hear and open their eyes but unable to move

associated wit hnarcolepsy and familial inheritance, isolated or substance-induced

higher incidence when sleeping supine

Question 2

3 types of sleep paralysis and their characteristics

Answer 2

intruder - threatening presence with other hallucinations

incubus - difficulty breathing, suffocation, pressure, pain, feeling of impending death
- correlaiton between intruder and incubus - both correlated with fear

vestibular-motor - acceleration, floating, flying, autoscopy (outof body experience)
- less correlated with the other two

Question 3

link betwen sleep paralysis and fear and anxiety

Answer 3

Experience is typically scary

trauma, porr sleep quality, stress linked to higher incidence of sleep paralysis

fear can arise due to suppression of respiratory movement (unable to increase respiratory rate when woken up)

involvement of amygdala - brain attempts to resolve fear by creating athreat

Question 4

Epidimeology of sleep paralysis

Answer 4

varying prevalence rate reported - 3-62%

occurs mostly in adolescent period

occurence deceases with age

more prevenlent in shift-work population

thought to be due to disturbances in sleep-wake system

Question 5

symptoms of narcolepsy

Answer 5

mandatory - excessive daytime sleepiness (EDS)

typically present

1. cataplexy
2. hypnagogic or hypnopompic halluciations
3. sleep paralysis

Question 6

what is cataplexy

Answer 6

sudden loss of muscle tone in response to emotional stimuli

knee jerk reflex reduced

Question 7

link betwen REM and narcolepsy

Answer 7

REM sleep component intruding into wake

• cataplexy - REM atonia
• sleep paralysis - again atonia
• hallucination - intrusion of dreams
• REM appears at sleep onset and MSLT (NANI THE FUCK IS MSLT)

Question 8

prevalence of narcolepsy

Answer 8

adolescnet onset
equally in males and females
lowest in israel and highest in japan

Question 9

what possibly causes narcolepsy

Answer 9

low orexin in most cases, receptor abnormality

Question 10

what is the mechanism behind cataplexy

Answer 10

normally orexin excites vlPAG and NE, 5HT which inhibit SLD

(SLD excites MM and spinal interneuron who inhibites motor neuron, thus SLD inhibit motor neuron = REM atonia)

in cataplexy AMYGDALA takes over inhibiting vlPAG - allowing SLD to produce atonia
amygdala alos directly excites SLD

Question 11

How is the sleep of someone with narcolepsy different from sleep of a normal person

Answer 11

1. early REM intrusion
2. less SWS (to be confirmed? i dont remember)
3. more awakening
4. REM looks funny
5. JUST CHECK LETURE CAPTURE
6. why does low level of orexin affect sleep???

Question 12

How to diagnosis narcolepsy

Answer 12

narcolepsy emerges in teens - 20s, often following illness/vaccination - involvement of autimmune system

diagnosis

• abormal immune function - HLA subtyping
• sleep study (short sleep onset latency, short REM latency, increases awakening)
• multiple sleep latency test (rapid sleep onset, REM onset)

Question 13

treatment ofr narcolepsy

Answer 13

1.Excessive daytime sleepiness - planned naps, CNS stimulants, sodium oxybate
cataplexy - antidepressants, sodium oxybate - why does antidepressants work???
orexin agonists - but orexin can’t cross BBB - no luck yet

Question 14

what is REM behaviour disorder

Answer 14

loss of atonia in REM - act out dreams

Question 15

link between REM behaviour disorder and degenerative diseases?

Answer 15

Often precedes degenerative disease by many years (Parkinson’s, Lewy body dementia, multiple systems atrophy).
Diagnosis may provide an opportunity for early intervention for such disorders.

Question 16

What is the mechanism of REM muscle atonia

Answer 16

Lesion of sublateral dorsal (SLD) region resulted in REM sleep without atonia in rats.
Injected tracer into this region and found projections through the pons and medulla to the spinal ventral horn (contain thealpha-motor neurons).

Question 17

Why do you still even get REM sleep with lesion of the SLD?

Answer 17

Two populations of SLD neurons: one part of flip flop switch and other responsible for atonia.
Human RBD: PPT/LDT involved too.

Question 18

signs and symptoms of somnambulism/sleepwalking

Answer 18

Signs and Symptoms:
Performing complex behaviours while asleep
Walking
Talking
Driving
Hard to awaken while experiencing and episode
Little or no memory of the event after waking
Confusion and distress when aroused during episode

Question 19

Sleepwalking onset and prevalence

Answer 19

Paradoxically occurs during NREM (SWS) sleep
Most sufferers experience it chronically
Seems to have familial/genetic component
Onset usually in childhood and frequency of episodes is greater in childhood than adulthood
Prevalence ~1-15%

Question 20

sleepwalking pathology

Answer 20

Speculation that it is incomplete arousals from deep sleep or brain attempting to directly transition from deep sleep to wake
The result is most likely activation of isolated neuronal networks permitting movement

Question 21

risk factors underlying sleepwalking

Answer 21

Associated with depression, alcoholism, OCD, anti-depressant and sedative medication
Triggers: sleep deprivation, illness, excessive deep sleep (SSRIs or sleeping pills) can predispose to an episode

Question 22

treatment of sleepwalking

Answer 22

Improve sleep hygeine
Avoiding triggers – sleep dep, alcohol, drugs
Create safe space or put measures in place to protect them and others
To wake or not to wake?