Sleep Disorders and their treatment Flashcards
(46 cards)
what is stage 1 in the sleep cycle ?
light sleep, transition from alpha waves at 8-12 Hz to theta waves at 4-7Hz
what is stage 2 of the sleep cycle ?
this is unconscious sleep, sleep spindles occur at 12-16Hz
what are stages 3 and 4 of the sleep cycle ?
these are sometimes considered the same stage
deep sleep, slow wave sleep, delta waves of 0.5-4Hz
how many sleep cycles do you go through each night and describe the events in sleep cycles ?
4-5 cycles, each lasting about 1.5-2 hours
the cycles have more non-REM sleep earlier in the night
the time spent in stage 2 and REM increases through the night
how can sleep patterns be disturbed ?
disturbed by sleep disorders, medication and drugs of abuse
patterns also change with age
what NT are involved in maintaining wakefulness?
noradrenaline serotonin dopamine histamine acetylcholine orexin
what NT are involved in promoting sleep ?
melatonin
GABA
adenosine
what happens with the release of orexin when your awake and when your asleep?
when your awake it is released at the TMN- tuberomamillary nucleus
when your asleep it is not released
what is happening when you are in the awake state ?
the ventrolateral preoptic nucleus has GABAergic neurons that are under tonic inhibition by noradrenaline
what happens in endogenous NREM sleep?
noradrenergic neurones in the locus coeruleus are inhibited by GABA
this in turn releases the tonic noradrenergic inhibition of the ventrolateral preoptic nucleus
what happens when the VLPO is released from inhibition ?
it enables the VLPO to release GABA onto the TMN
this inhibits the release of the arousal promoting histamine into the cortex
this induces loss of consciousness
what are the other pathways involved in NREM sleep ?
VLPO projects to all the monoaminergic cholinergic and orexinergic arousal nuclei such as tmn, LC, DR, PPTg, LDTg, PeF
these project to the cortex where they release arousal promoting neurotransmitters to promote wakefulness
what can be measuredd to assess sleep ?
sleep onset latency total sleep time sleep efficiency wake time after sleep onset (WASO) number of awakenings sleep quality
what is a subjective tool used to assess sleep measurements ?
sleep diary
what objective tools can be used to assess sleep measurements ?
MULTIPLE SLEEP LATENCY TEST
- assess daytime sleepiness by measuring the time it takes for patients to fall asleep (daytime nap)
POLYSOMNOGRAPHY
- typically used during an overnight sleep study
- electrodes continuouslu record eeg, REMs and muscle tone
WRIST ACTIGRAPHY
- used adjunctively with other objective data
- records movements of the wrist to determine time spent sleeping
what is important to record when carrying out a polysomnography ?
blood oxygen levels because some patients can stop breathing briefly during their sleep - this normally occurs in the elderly
what are some examples of sleep disorders ?
insomnia circadian rhythm disorders narcolepsy parasomnias obstructive sleep apnoea syndrome
what are circadian rhythm disorders ?
jet-lag
shift-work disorder
advanced and delayed sleep phase syndromes
what are parasomnias ?
sleep walking night terrors bruxism - grinding of teeth restless leg syndrome periodic leg movement disorder
what happens to our circadian rhythm when we are placed in a cave or special apartment without clocks or time cues ?
people tended to go to bed an hour later and get up an hour later each day
what does melatonin do ?
it promotes sleep
how many people suffer from insomnia ?
it is a significant problem which is being increasingly recognised
10-30% of the population suffer from it
50% of insomnia patients have reduced daytime fucntioning - inability to concentrate, reduced energy, memory problems, work hazard
what is primary insomnia ?
symptoms present for greater than 1 month
no associated mental or physical disorder
it is also known as chronic insomnia
what is transient insomnia ?
associated with specific events- acute periods of stress or anxiety
