Sleep Flashcards
What is the role of SCN and pineal gland in sleep + what are the ascending arousal system components?
Suprachiasmatic nucleus (SCN) within anterior
hypothalamus regulates circadian rhythm
Pineal gland secretes melatonin to regulate timing of sleep
What are the 3 stages of sleep?
Three brain states seen on EEG
– Wake
– Non rapid eye movement sleep (NREM – divided into N1, N2 and N3)
– Rapid eye movement (REM)
What happens in REM?
- Awake brain – paralysed body
- During REM - Muscle atonia – a descending inhibitory signal from the pons (PPRF) to the spinal motoneurons leads to a profound reduction of skeletal muscle tone, apart from ocular muscles and diaphragm.
- Sleep paralysis – abrupt wake before muscle tone restored, with dream like hallucinations
How is sleep-wake controlled?
A mutually inhibitory circuit
controlled within brainstem
Orexin stabilizes this circuit – a hypothalamic neuropeptide – these neurons are lost in narcolepsy
What neurotransmitters regulate the sleep-wake cycle?
How do you asses hypersomnia?
The Epworth Sleepiness
Normal 3-7
Insomnia 0-2
Excess sleepiness > 10
Obstructive sleep apnoea
def, rf, dx, mx
Snoring with partial or complete collapse of the upper airway leading to complete or partial reduction in airflow (apnoea or hypopnoea)
Cycle repeats throughout sleep leading to fragmented night sleep, daytime sleepiness, prolonged, unrefreshing sleep, sore throat
Risk factors – age, male gender, obesity, large tonsils and adenoids in children, sedative drugs
eg opioids, alcohol.
High risk populations – treatment resistant
hypertension, treatment resistant atrial
fibrillation, high dose opioids, bariatric surgery
screening tool- STOP BANG
CPAP therapy to manage
What is the main cause of central apnoea?
high dose opioids
What is narcolepsy with cataplexy?
Human narcolepsy is an auto-immune condition due to the loss of the hypocretinergic neurons in the hypothalamus.
sx
Cataplexy – emotionally triggered loss of muscle tone
Hypnogogic hallucinations
Excessive daytime sleepiness
Sleep paralysis
Sleep fragmentation at night
What is Non REM (NREM) Parasomnia?
Incomplete awakenings from slow wave sleep including:
- Night terrors
- Hypnagogic hallucination
- Sleepwalking
- Sleep eating
- Sleep sex
- Confusional arousals
Often a family history
Typically first half of the night and without recall or only patchy, can occur first hour, eyes open, minutes at a time, complex, non-stereotyped motor behaviours. May not need treatment
Affected by anything that disrupts sleep
(OSA, restless legs, shift work, stress)
What is NREM parasomnia
Incomplete awakenings from slow wave sleep (N3)
- Night terrors
- Hypnagogic hallucination
- Sleepwalking
- Sleep eating
- Sleep sex
- Confusional arousals
Typically first half of the night and without recall or only patchy, can occur first hour. Eyes open
Affected by anything that disrupts sleep (OSA, restless legs, insomnia)
Strongly affected by daytime
stresses/schedule
What is REM sleep behaviour disorder?
Insidious progressive disorder of dream enactment often with injury
and dream recall. There is loss of normal REM atonia and a strong association with neurodegenerative disorders such as parkinson’s or dementia
What is insomnia?
Difficulty falling asleep and/or difficulty staying asleep with daytime impact. At least 3 months, >3 days a week
treatment includes cognitive behavioural therapy for insomnia
