Sleep and Wakefulness Flashcards
Sleep current definition
Highly organized state generated by the cooperative interplay of many bx and neural components
EEG of an awake brain
Low voltage, high frequency, fast activity
EEG of an asleep brain
Amplitude higher, but less frequency
Slow, synchronized oscillatory, activity is low
EOG is looking at what
eye movements to segment sleep based on the eye movement
EMG is looking at what
muscle tone
2 main phases of sleep
NREM
REM
NREM has how many stages
4
Stage 1 NREM
Transition from awake to sleeping
Start to see dec in EEG high freq activity
Stage 2 NREM
First true stage of sleep
EEG shows spindle waves and K complexes
Stage 2 NREM - spindle waves and K complexes are reflective of what
Oscillations between thalamus and cerebral cortex - reflective of gradual relaxation and hyperpolarization of neurons
Stage 2 NREM - what happens
Muscle tone dec Arousal dec Respiration dec Temp dec Eyes roll back and forth
Stage 3 NREM
See greater delta wave oscillations, greater slow wave oscillations - signal inc synchronization of cortical and thalamic activity
Further reduction in arousal
Stage 4 NREM
Dominance of slow wave activity
Deepest stage of sleep
Sleep cycle consists of
Stage 1-4 NREM
Reverse 4-1
REM
What happens as the sleep cycle continues throughout the night
Depth of NREM decreases
Duration in REM increases
Sleep in REM - what happens on EEG
It goes back to state of higher frequency activity
Brain is activated
Sleep in REM - what happens
Inc head movement
Inc HR and RR
Dreams are longer, visual, emotional, not connected to events of daily life
Sleep in REM - what percent of total sleep time
25%
Circadian Rhythms - are what
day-night cycle
What is responsible for Circadian rhythms
Specific retinal ganglion cells that respond to light
Project to suprachiasmic nucleus in the hypothalamus
Firing frequency of the neurons in the nucleus follow an endogenous circadian rhythm
What is the master clock, pacemaker that organizes sleep
Suprachiasmatic nucleus in the hypothalamus
Sleep - rhythm within sleep of NREM and REM is controlled by what
Brainstem appears to be critical for switch
REM on cells that fire during REM - cholinergic
REM off cells that maximally fire at offset of REM - serotonergic
Sleep - rhythm within sleep of NREM and REM - where are the REM on and off cells located
Pontine and geniculate nuclei of the brainstem
Sleep deficit is what
Level of sleepiness
Naturally builds up throughout the day
Circadian rhythm is defined as what when it comes to determining sleep drive
Defines alertness peaks and wanes throughout the day
Sleep drive is defined as what
the difference beteen sleep deficit (sleepiness) and circadian rhythm (alertness)
As you get older what happens
Found that people don’t sleep as much
Sleep disorders - what percent of people experience significant difficulties with sleep on occasion
more than 50%
Statistics for people who suffer from chronic sleep problems
1 in 5 people
Disruption of sleep and waking is the most common prevalent health disorder in the US! - most common complaint when people go to see their PCP
The most common for of sleep disruption is
insomnia
Insomnia description
Can be prolonged/severe or temporary/mild
Incidence inc with age
More common in F
Insomnia is defined as what
Difficulty falling asleep, staying asleep or both
Often associated with depression
Meds for insomnia
Benzodiazapines
Antihistamines
Antidepressants
Sleep apnea is what
cessation of breathing during sleep
fragmentation of sleep, decrease in sleep quality, daytime sleepiness!
Most common type of sleep apnea
Obstructive sleep apnea - physical obstruction of pharynx/breathing can cease for 10 sec or more
Sleep apnea - incidence
increases with age
more common in M
Sleep apnea - risk factor for
stroke
Narcolepsy - impacts what % of pop
0.04%
Narcolepsy description
Sleep and sleep mechanisms invade daytime periods
Sleep at night is fragmented and disrupted
Narcolepsy - 5 symptoms
1 Sleep attacks during day
2 cataplexy (sudden mm tone, fall, but conscious)
3 hallucinations during transition from sleep to wake
4 sleep paralysis during transition
5 disturbed nocturnal sleep
Meds - narcolepsy
amphetamines/CNS stimulant
antidepressants
Exercise and sleep
People who slept better were people who exercised
Correlation but no evidence for causality
Exercise can help sleep by
Reducing anxiety, reduce depression, temperature regulation, circadian phase shifting effect, improve RLS
Sleep disorders and stroke -
Obstructive sleep apnea
Insomnia
Habitual snoring
Untreated sleep disorders do what to stroke outcome
Lengthen hospital stay, influence stroke outcome and re-occurrence
Insomnia in TBI
30-70% of TBI pt report s/s of insomnia
Can lead to exacerbation of s/s
Implications of insomnia and TBI
Compromise rehab ability or ability for pt to return to work
Sleep disorders in chronic TBI
Hypersomnia - 50% - mostly due to sleep apnea, narcolepsy, and periodic limb movement disorder
Insomnia - 25% mostly due to sleep maitenence insomnia and sleep onset insomnia
Sleep changes common in acute or chronic TBI
BOTH
