10-2 CIS Sleep Apnea - Vosko Flashcards
What are some common situations when sleep patterns change?
- During illness (“sick behavior”)
- Affective changes (depression, stress, etc.)
- Throughout the aging process
- Seasonal changes (esp. during time changes)
- Taking medication
- Diet
- Hormonally-induced changes
If sleeping patterns are changing due to medication, aging, illness, diet, hormones, etc. do they need aggressive treatment?
Not necessarily - evaluate thoroughly, treat only what’s needed
What are some sleep disorders that can cause excessive daytime sleepiness (EDS)? (name 6)
Insomnia
Parasomnias
Hypersomnias
Sleep-Disordered Breathing (SDB)
Circadian Rhythm Disorders
Neurodegenerative Disorders
What are the types of insomnia? What generally can cause them?
Initiation insomnia - have difficulty falling asleep
Maintenance insomnia - have difficulty maintaining sleep/staying asleep through the night
Can be caused by pyschological, neurogenic, genetic or pharmaceutical causes
What is a parasomnia? What can cause them?
Parasomnia - when your brain thinks you’re asleep, but your body thinks you’re awake
- leads to people sleepwalking or acting out their dreams during adulthood
Mechanisms: Neurogenic, pharmaceutic or unknown reasons
What is a type of hypersomnia? What causes this disorder?
Narcolepsy - autoimmune process that destroys orexin producing neurons
What are some types of SDB? What causes them?
OSA (Obstructuve sleep apnea)
CSA (Central sleep apnea)
Hypoventilation
Mechanisms - structural, body habitus, neurological, and/or pharmaceutical mechanisms
What are some types of Circadian Rhythm Disorders? What can cause them?
Jet lag - travel
ASPS - advanced sleep phase disorder (genetic, person always wants to wake up and go to bed a few hours before everyone else)
DSPS - delayed sleep phase disorder (Genetic basis, person always wants to wake up and go to bed a few hours later than everyone else. Also extremely prevalent in teenagers and young adults, due to hormones.)
Mechanisms - Vosko listed physiological, pharmaceutical, and genetics
What are some neurodegenerative disorders that can cause EDS?
Parkinson’s
ALS
Alzheimer’s
Mechanisms - neuro, pharm
What types of sleep disorders that cause EDS can a PSG (polysomnography) suss out?
Insomnia - both types, initiation and maintenance
Parasomnias
Hypersomnias, narcolepsy
SDB - all types
What is actigraphy testing good for? What is it?
Actigraphy - small device, worn like a wristwatch. Will track body movement 24 hours a day for several weeks.
Good for testing circadian rhythm disorders
How do you tests for neurodegenerative disorders that cause EDS?
Vosko listed imaging, motor tests, cognitive tests
How can you differentiate (without any testing) the difference between tiredness/fatigue and EDS (pathological levels of tiredness)?
Use Epworth sleepiness scale
1-10 = normal range of fatigue
11-24 = EDS
Your patient has fallen asleep while talking to you in their clinic visit, and their Epworth scale is 24. What is your next step?
Determine the nature of what is causing their EDS:
- Insomnia
- Parasomnia
- Hypersomnia
- Sleep-disordered breathing
- Circadian rhythm disorder
- Neurodegenerative disorder
You want to order a sleep study/PSG on your patient that just fell asleep on you. Upon waking, the patient doesn’t want to do the study and that they “sleep fine”. What do you tell them?
Self-perception of sleep isn’t always accurate
Can have:
microarousals
micro-sleeps
perceived insomnia
What us a micro-arousal?
•Brief awakenings from sleep (usually < 15 seconds). Do not have conscious recollection.
(Can frequently occur as a result of sleep apnea)
What is micro-sleep?
•Brief (seconds in duration) sleep episodes during wakefulness. May not have conscious recollection.
What is perceived insomnia?
•Believing one has insomnia while showing the behavioral and polysomnographic characteristics of someone with normal sleep.
What are the 2 major periods of sleep?
non-REM or Slow Wave Sleep (SWS)
REM
How are SWS and REM similar, physiologically?
Both have:
increased arousal thresholds (waking from sleep)
decreased thermoregulation (REM more so than SWS)
decreased postural mm tone (REM more so than SWS)
How is REM different from SWS, physiologically?
SWS
- 4 stages
- synchronous EEG
- 75% of total sleep time
- prominent in early phases of sleep
REM
- it’s own stage, just 1 stage
- asynchronous EEG
25% of total sleep time
- prominent in later phases of sleep
What is mm tone? Why is it necessary?
MM tone is the resting level of tension in a mm
- allows mm to make an optimal response to voluntary or reflexive movement by keeping them in a state of readiness to resist stretch
Why is mm tone reduced during sleep?
mm tone is generated in part by the Reticular Activating System (RAS) sending signals to the mm spindle fibers via cortical neurons or UMNs
What regulates respiratory mm?
tonic input and a phasic (respiratory drive) input regulate respiratory mm
How does input to mm of respiration change during SWS?
tonic input is diminshed
respiration relies more on phasic inputs to motor neurons
- small amounts of phase inputs will sum to create an action potential
How does input to mm of respiration change during REM?
Both tonic and phasic inputs are very diminished
- heavy reliance on phrenic motor neurons for sleep-related breathing
- phrenic nerve only innervates diaphragm, so diaphragm is main mm of respiration during REM sleep
How is reduction in tonic input to mm of respiration during sleep accomplished?
via GABA-ergic and/or Glycinergic activity in the spinal cord and CN nuclei
How long is a cycle of sleep?
cycle through non-REM and REM in ~90 minute cycles
When does more REM occur?
Longer periods of REM in second half of night
What does deprivation of NREM sleep lead to?
“rebound” of NREM sleep - having more NREM sleep during subsequent sleep to ‘catch up’
What does deprivation of REM sleep leads to what?
Deprivation of REM sleep leads to a “rebound” of REM sleep
What does SOREMP stand for? What disorder does it indicate?
SOREMPs (Sleep Onset REM Periods)
indicative of sleep disorders (eg. Narcolepsy)
What measures physiological changes during sleep?
PSG - polysomnography, sleep study
What are some important signals in a PSG that allows you to determine wake, REM, and SWS?
EEG - electroencephalogram
EOG - electrooculogram
EMG - electromyelogram
How do EEG signals differ between wake, SWS and REM?
- low amplitude, high frequency in wake
- low amplitude, high frequency in REM
- high amplitude, low frequency in SWS
How do EOG signals differ throughout wake, SWS and REM?
- high frequency, reflects eye movements in wake
- reflects frequency and amplitude of EEG in SWS
- shows rapid eye movements, high amplitude and frequency, in REM
How do EMG signals change in wake, SWS and REM?
- high frequency and higher amplitude in wake
- slightly diminished in SWS
- very diminished in REM
What EEG findings define stage 2 SWS sleep?
K complexes - sudden, high amplitude positve and negative deflections
sleep spindles - 1-2 second burst of high frequency activity
Stages 3 and 4* of sleep are defined by what EEG findings?
Delta waves - high amplitude, low frequency waves
* stage 4 sleep is no longer a recognized stage of sleep by the American Academy of Sleep Medicine, and is not something you should expect or really worry about in the real world. No accredited sleep lab will score a sleep study with stage 4 sleep.
How do benzodiazepines affect sleep stages?
•Benzodiazepines suppress NREM sleep
–(Valium)
–*Most sedative hypnotics are benzodiazepines (GABA-ergic agonists)
How do anti-depressants affect sleep stages?
•Anti-depressants suppress REM sleep
–(Fluoxetine): Prozac Eyes - EOG finding, slow rolling eye movements throughout all stages of sleep
•Withdrawal from drug causes rebound of the sleep it normally suppresses
How does Ambien affect sleep stages?
Can shorten time to sleep onset, but doesn’t alter the way people move through sleep stages throughout the night
- can induce parasomnias
- can be used to bring someone out of a coma
How is wake mediated in the brainstem and brain? What neurotransmitters are at play?
Reticular activating system releases 5HT (serotonin) and induces dopamine, histamine, orexin, and acetylcholine release into other areas of the brainstem and cerebrum
-5HT also released on thalamus, and norepinephrine and 5HT also released onto pons and medulla
How is sleep mediated in the brainstem and brain? What NTs are at play?
VLPO in thalamus releases GABA onto cerebrum, most structures that release excitatory NTs in brainstem
What stage of sleep is most disrupted with obstructive sleep apnea (OSA)? Why?
REM is most disrupted phase of sleep, other phases will be disrupted too depending on the severity of the OSA
Respiration during REM is dependent on diaphragm activity, few other mm of respiration available for help
•If there is respiratory distress of any origin, it will likely first show up during sleep. REM is the most sensitive period in sleep to show any respiratory dysfunction.
