10-2 CIS Sleep Apnea - Vosko

Question 1

What are some common situations when sleep patterns change?

Answer 1

• 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

Question 2

If sleeping patterns are changing due to medication, aging, illness, diet, hormones, etc. do they need aggressive treatment?

Answer 2

Not necessarily - evaluate thoroughly, treat only what’s needed

Question 3

What are some sleep disorders that can cause excessive daytime sleepiness (EDS)? (name 6)

Answer 3

Insomnia

Parasomnias

Hypersomnias

Sleep-Disordered Breathing (SDB)

Circadian Rhythm Disorders

Neurodegenerative Disorders

Question 4

What are the types of insomnia? What generally can cause them?

Answer 4

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

Question 5

What is a parasomnia? What can cause them?

Answer 5

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

Question 6

What is a type of hypersomnia? What causes this disorder?

Answer 6

Narcolepsy - autoimmune process that destroys orexin producing neurons

Question 7

What are some types of SDB? What causes them?

Answer 7

OSA (Obstructuve sleep apnea)

CSA (Central sleep apnea)

Hypoventilation

Mechanisms - structural, body habitus, neurological, and/or pharmaceutical mechanisms

Question 8

What are some types of Circadian Rhythm Disorders? What can cause them?

Answer 8

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

Question 9

What are some neurodegenerative disorders that can cause EDS?

Answer 9

Parkinson’s

ALS

Alzheimer’s

Mechanisms - neuro, pharm

Question 10

What types of sleep disorders that cause EDS can a PSG (polysomnography) suss out?

Answer 10

Insomnia - both types, initiation and maintenance

Parasomnias

Hypersomnias, narcolepsy

SDB - all types

Question 11

What is actigraphy testing good for? What is it?

Answer 11

Actigraphy - small device, worn like a wristwatch. Will track body movement 24 hours a day for several weeks.

Good for testing circadian rhythm disorders

Question 12

How do you tests for neurodegenerative disorders that cause EDS?

Answer 12

Vosko listed imaging, motor tests, cognitive tests

Question 13

How can you differentiate (without any testing) the difference between tiredness/fatigue and EDS (pathological levels of tiredness)?

Answer 13

Use Epworth sleepiness scale

1-10 = normal range of fatigue

11-24 = EDS

Question 14

Your patient has fallen asleep while talking to you in their clinic visit, and their Epworth scale is 24. What is your next step?

Answer 14

Determine the nature of what is causing their EDS:

• Insomnia
• Parasomnia
• Hypersomnia
• Sleep-disordered breathing
• Circadian rhythm disorder
• Neurodegenerative disorder

Question 15

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?

Answer 15

Self-perception of sleep isn’t always accurate

Can have:

microarousals

micro-sleeps

perceived insomnia

Question 16

What us a micro-arousal?

Answer 16

•Brief awakenings from sleep (usually < 15 seconds). Do not have conscious recollection.

(Can frequently occur as a result of sleep apnea)

Question 17

What is micro-sleep?

Answer 17

•Brief (seconds in duration) sleep episodes during wakefulness. May not have conscious recollection.

Question 18

What is perceived insomnia?

Answer 18

•Believing one has insomnia while showing the behavioral and polysomnographic characteristics of someone with normal sleep.

Question 19

What are the 2 major periods of sleep?

Answer 19

non-REM or Slow Wave Sleep (SWS)

REM

Question 20

How are SWS and REM similar, physiologically?

Answer 20

Both have:

increased arousal thresholds (waking from sleep)

decreased thermoregulation (REM more so than SWS)

decreased postural mm tone (REM more so than SWS)

Question 21

How is REM different from SWS, physiologically?

Answer 21

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

Question 22

What is mm tone? Why is it necessary?

Answer 22

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

Question 23

Why is mm tone reduced during sleep?

Answer 23

mm tone is generated in part by the Reticular Activating System (RAS) sending signals to the mm spindle fibers via cortical neurons or UMNs

Question 24

What regulates respiratory mm?

Answer 24

tonic input and a phasic (respiratory drive) input regulate respiratory mm

Question 25

How does input to mm of respiration change during SWS?

Answer 25

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

Question 26

How does input to mm of respiration change during REM?

Answer 26

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

Question 27

How is reduction in tonic input to mm of respiration during sleep accomplished?

Answer 27

via GABA-ergic and/or Glycinergic activity in the spinal cord and CN nuclei

Question 28

How long is a cycle of sleep?

Answer 28

cycle through non-REM and REM in ~90 minute cycles

Question 29

When does more REM occur?

Answer 29

Longer periods of REM in second half of night

Question 30

What does deprivation of NREM sleep lead to?

Answer 30

“rebound” of NREM sleep - having more NREM sleep during subsequent sleep to ‘catch up’

Question 31

What does deprivation of REM sleep leads to what?

Answer 31

Deprivation of REM sleep leads to a “rebound” of REM sleep

Question 32

What does SOREMP stand for? What disorder does it indicate?

Answer 32

SOREMPs (Sleep Onset REM Periods)

indicative of sleep disorders (eg. Narcolepsy)

Question 33

What measures physiological changes during sleep?

Answer 33

PSG - polysomnography, sleep study

Question 34

What are some important signals in a PSG that allows you to determine wake, REM, and SWS?

Answer 34

EEG - electroencephalogram

EOG - electrooculogram

EMG - electromyelogram

Question 35

How do EEG signals differ between wake, SWS and REM?

Answer 35

• low amplitude, high frequency in wake
• low amplitude, high frequency in REM
• high amplitude, low frequency in SWS

Question 36

How do EOG signals differ throughout wake, SWS and REM?

Answer 36

• 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

Question 37

How do EMG signals change in wake, SWS and REM?

Answer 37

• high frequency and higher amplitude in wake
• slightly diminished in SWS
• very diminished in REM

Question 38

What EEG findings define stage 2 SWS sleep?

Answer 38

K complexes - sudden, high amplitude positve and negative deflections

sleep spindles - 1-2 second burst of high frequency activity

Question 39

Stages 3 and 4* of sleep are defined by what EEG findings?

Answer 39

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.

Question 40

How do benzodiazepines affect sleep stages?

Answer 40

•Benzodiazepines suppress NREM sleep

–(Valium)

–*Most sedative hypnotics are benzodiazepines (GABA-ergic agonists)

Question 41

How do anti-depressants affect sleep stages?

Answer 41

•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

Question 42

How does Ambien affect sleep stages?

Answer 42

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

Question 43

How is wake mediated in the brainstem and brain? What neurotransmitters are at play?

Answer 43

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

Question 44

How is sleep mediated in the brainstem and brain? What NTs are at play?

Answer 44

VLPO in thalamus releases GABA onto cerebrum, most structures that release excitatory NTs in brainstem

Question 45

What stage of sleep is most disrupted with obstructive sleep apnea (OSA)? Why?

Answer 45

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.