CM: Sleep Disorders I Flashcards
What are the different stages of sleep?
awake: low voltage, fast waves, minimal synchrony - alpha waves emerge as one gets sleepy
stage 1: low voltage theta waves (slower and higher than awake)
stage 2: sleep spindles and K-complexes (slow triphasic waves)
stage 3 and 4: high voltage, low frequency delta waves
REM: similar to stage 1 on EEG
What is the typical sleep pattern of a person w normal sleep?
sleep latency = wake-stage 2
REM in cycles every 90 min - each episode gets longer, majority later in night/earlier in morning
REM latency = 90 min
stage 2 is most predominant
majority of delta stages (3&4) occur in first half of night
What are the physiologic findings of REM sleep?
increased O2 consumption and pulse, BP, RR similar to or greater than wakefulness
decreased muscle tone
erections
can recall dreams if awakened, quickly alert
thermoregulation affected –> temp variation based on environment
What are the physiologic findings of NREM sleep?
restorative - increased by starvation and exercise
cannot recall dreams if awakened, briefly disoriented
What are the effects of depression on sleep?
decreased REM latency, REM shifts toward first half of night, increased percentage of total sleep occupied by REM
What does brief REM deprivation cause?
transient antidepressant effect
but when person then allowed to sleep w/o interruption –> increased REM (rebound REM) and depression returns
What are dyssomnias?
sleep disorders defined by disturbance in amount, quality or timing of sleep
What is narcolepsy?
def of orexin (suppresses REM and increases arousal)
sudden sleep attacks, excessive daytime sleepiness, cataplexy (from strong emotions)
sleep paralysis or hallucinations upon sleep/wake transitions
How can circadian rhythm sleep disorders be recognized?
mismatch b/w one’s imposed sleep-wake schedule and one’s innate sleep wake cycle
delayed sleep phase (going to bed and waking up late), jet lag, shift work type
How can periodic limb movement disorder be recognized?
brief leg muscle contractions lasting 5-15 sec and recurring every 20-60 sec discovered on polysomnogram
usually in NREM sleep but person not aware
–>mini-arousals, non-refreshing sleep, excessive daytime sleepiness
How can restless leg syndrome be recognized?
uncomfortable sensations and restlessness when trying to fall asleep –> delayed sleep onset
intense urge to move or walk –> transient relief
majority also have periodic limb movement on polysomnography
may be secondary to iron def or peripheral neuropathy
What are parasomnias?
disruptive events that occur during sleep or during sleep/wake transition
How can nightmare disorder be recognized?
frequent awakenings secondary to nightmares that occur during REM and result in clinically sig impairment or distress
rapid alertness upon wake and detailed recall of dream
How can sleep terror disorder be recognized?
wakening beginning w scream and autonomic hyperarousal
person not alert, doesn’t respond to gentle reassurance and typically falls back asleep rapidly w/o memory of dream or episode, lasts 30 sec - 3 min
associated w delta sleep (first 1/3 of night)
What is somnambulism?
sleep walking disorder
