Resp 04: Physiology And Disorders Of Sleep

Front 1

What are the functions of sleep?

Back 1

- Restoration and recovery
- Energy conservation
- Behavioral adaptation
- Neural networks / plasticity

Front 2

What are the five behavioral characteristics of sleep in animals?

Back 2

- Behavioral quiescence (inactivity)
- Stereotypic posture
- Elevated arousal threshold
- Rapid state reversibility
- Achieved spontaneously

Front 3

What are the features of brain waves during the awake stage?

Back 3

Low voltage, random and fast

Front 4

What are the features of brain waves during the drowsy stage?

Back 4

- 8-12 Hz
- Alpha waves

Front 5

What are the features of brain waves during the stage 1 sleep?

Back 5

- 3-7 Hz
- Theta waves

Front 6

What are the features of brain waves during the stage 2 sleep?

Back 6

- 12-14 Hz
- Sleep spindles and K complexes

Front 7

What are the features of brain waves during the stage 3-4 sleep?

Back 7

- 1/2 - 2 Hz
- Delta waves > 75 µV

Front 8

What are the features of brain waves during the REM sleep?

Back 8

- Low voltage
- Random, fast w/ "sawtooth pattern"

Front 9

What is this wave pattern characteristic of?

Back 9

Awake
Low voltage, random and fast

Front 10

What is this wave pattern characteristic of?

Back 10

Drowsy Stage
- 8-12 Hz
- Alpha waves

Front 11

What is this wave pattern characteristic of?

Back 11

Stage 1 Sleep
- 3-7 Hz
- Theta waves

Front 12

What is this wave pattern characteristic of?

Back 12

Stage 2 Sleep
- 12-14 Hz
- Sleep spindles (bracket)

Front 13

What is this wave pattern characteristic of?

Back 13

Stage 2 Sleep
- 12-14 Hz
- K complexes (tall peak)

Front 14

What is this wave pattern characteristic of?

Back 14

Stage 3/4 Sleep:
- 1/2 - 2 Hz
- Delta waves > 75 µV

Front 15

What is this wave pattern characteristic of?

Back 15

REM Sleep:
- Low voltage
- Random, fast w/ "sawtooth pattern"

Front 16

How frequently do you go through cycles of REM sleep?

Back 16

Every 90-120 minutes (ultradian rhythm)

Front 17

A lesion where would cause narcolepsy?

Back 17

Lateral Hypothalamus

Front 18

A lesion where would cause hypersomnolence?

Back 18

Juncture of midbrain and posterior hypothalamus

Front 19

A lesion where would cause insomnia?

Back 19

Basal forebrain and anterior hypothalamus

Front 20

What happens if there is a lesion involving the lateral hypothalamus?

Back 20

Narcolepsy

Front 21

What happens if there is a lesion involving the juncture of the midbrain and posterior hypothalamus?

Back 21

Hypersomnolence

Front 22

What happens if there is a lesion involving the basal forebrain and anterior hypothalamus?

Back 22

Insomnia

Front 23

What happens if there is a lesion to the pontomesencephalic brainstem (lesion between pons and mesencephalon)?

Back 23

Coma

Front 24

A lesion where can cause a coma?

Back 24

Pontomesencephalic brainstem (lesion between pons and mesencephalon)

Front 25

What do ascending arousal systems connect?

Back 25

- From brainstem and posterior hypothalamus
- To forebrain, cortical and subcortical targets

Front 26

What kind of neurons innervate ascending arousal system and cerebral cortex?

Back 26

Orexin neurons

Front 27

Which NTs inhibit cells in the PPT / LDT during W and NREM sleep?

Back 27

Aminergic (NE, 5HT, Histamine)

Front 28

Which NTs inhibit arousal during NREM sleep?

Back 28

GABA and Galanin from VLPO

Front 29

Which neurons drive REM sleep? Which are inhibited?

Back 29

- Cholinergic neurons
- Aminergic inputs are inhibited during REM, thereby dis-inhibiting the PPT/LDT

Front 30

What is happening at the PPT/LDT during REM and NREM sleep?

Back 30

- REM: disinhibited d/t silent aminergic inputs
- NREM: inhibited by aminergic inputs

Front 31

What signals cause REM sleep to be atonic (no muscular tone)?

Back 31

- Post-synaptic inhibition of motor neurons
- Hyperpolarization of motor neuron membranes
- Activated thalamus

Front 32

What hormone is responsible for the Circadian rhythm?

Back 32

Melatonin: high during the night and low during the day

Front 33

What happens if you have no cues to tell you when to go to bed (clocks/sun)?

Back 33

- Without cues you start going to bed an hour later everyday
- Your body thinks the day has about 26 hours without cues vs 24 hours with cues

Front 34

What kind of somatic activity occurs during NREM vs REM sleep?

Back 34

- NREM: few motor events, body repositioning

- REM: paralysis, phasic events (rapid eye movements and muscle twitches)

Front 35

How does the CNS activation during NREM and REM sleep compare?

Back 35

NREM:
- mean discharge rate of neurons decreased
- cerebral glucose utilization is decreased overall

REM:
- mean discharge rate of neurons increased in many regions (PGO spikes and rapid eye movements)
- cerebral glucose utilization increased (resembles W)
- cerebral blood flow greatly increased

Front 36

How does the HR change during NREM vs REM sleep relative to when awake? Why?

Back 36

NREM:
- Slightly lower HR (70-->65 bpm)
- D/t more parasympathetic activity

REM (tonic):
- Lower HR (70-->60 bpm)
- D/t less sympathetic and more parasympathetic activity

REM (phasic):
- Higher HR (70-->80 bpm)
- D/t more sympathetic and more parasympathetic activity

Front 37

During what phase of sleep is the pupil diameter the greatest? Smallest?

Back 37

- Largest: REM phasic sleep
- Smallest: NREM and REM tonic sleep

Front 38

How does the BP compare for NREM and REM sleep?

Back 38

- NREM: BP tends to decrease
- REM: BP is highly variable

Front 39

How does the CO and blood vessel diameter compare for NREM and REM sleep?

Back 39

NREM:
- CO reduced
- Blood vessels dilated

REM:
- Blood vessels constricted

Front 40

Which hormones are elevated during sleep?

Back 40

- Growth Hormone
- Prolactin
- Melatonin

Front 41

Which hormones are suppressed during sleep?

Back 41

- Thyroid Stimulating Hormone
- Cortisol

Front 42

What happens to Cortisol during sleep?

Back 42

- Inhibited by sleep onset
- Progressive increase to high levels toward end of sleep

Front 43

What happens to TSH during sleep?

Back 43

- Inhibited by sleep onset
- Decreased across sleep period

Front 44

How does thermoregulation compare for NREM and REM sleep?

Back 44

NREM:
- Lowered temperature set point
- Shivering threshold lower
- Sweating at normal ambient temperatures

REM:
- No regulation
- No shivering response
- No sweating at high ambient temperature
- Body temperature drifts toward ambient (surroundings) temperature

Wakefulness:
- Full regulation

Front 45

How does HR, RR, and penile erection change during REM sleep?

Back 45

- HR elevated
- RR elevated
- Penile erection during REM sleep that gets stronger closer to morning

Front 46

What types of tests are used in sleep medicine?

Back 46

- Polysomnography
- Multiple Sleep Latency Testing
- Actigraphy
- Sleep Diary

Front 47

What kind of sleep disorders can be diagnosed by testing?

Back 47

- Obstructive sleep apnea
- Central sleep apnea
- Periodic limb movement disorder
- Parasomnias
- Narcolepsy
- Circadian rhythm disorders

Front 48

What is Polysomnography useful for diagnosing?

Back 48

- Obstructive Sleep Apnea (OSA)
- Periodic Limb Movement Disorder

Front 49

What is monitored on Polysomnography?

Back 49

- EEG: recording of the brain's spontaneous electrical activity
- EOG: measuring the resting potential of the retina in the human eye
- EMG: evaluating physiologic properties of muscles
- Respiratory electrodes

Get full physiologic monitoring.

Front 50

What is this an example of?

Back 50

Polysomnogram

Front 51

How do you determine the breathing pattern during Polysomnography?

Back 51

- Pressure sensor under nose
- Temperature detector

- Also have abdominal and thoracic belts to detect if there is effort to breathe

Front 52

What are the three characteristic patterns of apnea?

Back 52

- Obstructive
- Central
- Mixed

Front 53

What happens in an Obstructive Apnea?

Back 53

- Absence of airflow despite persistent ventilatory efforts
- Demonstrated by contraction of respiratory muscles such as the diaphragm

Front 54

What happens in a Central Apnea?

Back 54

- Absence of airflow due to the lack of ventilatory effort
- Since no effort is made to breathe, no airflow occurs

Front 55

What happens in a Mixed Apnea?

Back 55

- Includes both Obstructive and Central Apnea components
- Initial Central component followed by an Obstructive component

Front 56

Which of the sleep apneas are treated in the same way?

Back 56

- Obstructive
- Mixed

Front 57

Top is airflow, bottom is respiratory effort.
What kind of apnea? Why?

Back 57

Obstructive Apnea
- Absence of airflow despite persistent ventilatory efforts
- Demonstrated by contraction of respiratory muscles such as the diaphragm

Front 58

Top is airflow, bottom is respiratory effort.
What kind of apnea? Why?

Back 58

Mixed Apnea
- Includes both Obstructive and Central Apnea components
- Initial Central component followed by an Obstructive component

Front 59

Top is airflow, bottom is respiratory effort.
What kind of apnea? Why?

Back 59

Central Apnea
- Absence of airflow due to the lack of ventilatory effort
- Since no effort is made to breathe, no airflow occurs

Front 60

What can we diagnose from a sleep study?

Back 60

- Sleep disordered breathing (evaluation and treatment)
- Movement disorders of sleep
- Parasomnias

Front 61

When would a sleep study be useful for research?

Back 61

- Sleep structure in health and disease
- Insomnia and effect of medications

Front 62

What are the uses of a sleep diary?

Back 62

- Quantifying sleep
- Assessing pattern of sleep
- Assessing factors affecting sleep timing (e.g., alcohol, caffeine, exercise, medicine, nap, etc)

Front 63

What does Actigraphy do?

Back 63

- Motion detector
- Reinforces / compliments sleep diary

Front 64

What are these results from? What do they show?

Back 64

- Actigraphy
- Normal sleeper

Front 65

What are the uses of Actigraphy?

Back 65

- Objectively quantifies sleep over time
- Objectively assesses sleep patterns
- Can be useful for assessing larger numbers of people for sleep quality (research and clinical tool)
- Useful for assessing a child or cognitively impaired person's sleep pattern

Front 66

What is Actigraphy unreliable for?

Back 66

Insomnia

Front 67

What happens in a Multiple Sleep Latency Test (MSLT)?

Back 67

- Objectively measures sleepiness
- 20 minute opportunities to nap every 2 hours for 5 sessions in a row
- Unit of measure is minutes from lights out to sleep onset

Front 68

What is a normal sleep latency? What indicates pathological sleepiness?

Back 68

- Normal is > 10 minutes
- Pathologically sleepy is < 8 minutes

Front 69

What is normal / abnormal for REM sleep during MSLT?

Back 69

REM sleep during more than one nap is abnormal (it takes 90-120 minutes normally to get into REM sleep so even one nap is abnormal)

Front 70

What is measured in a Multiple Sleep Latency Test (MSLT)?

Back 70

- Central (1, 2) and Occipital (3, 4) EEG leads
- Chin movement (5) - should be no movement during REM
- EOG (eye movements seen in REM) (6, 7)
- EKG (8)

Front 71

Case: 5'7" 240 lb male w/ CAD and diabetes who is snoring very loudly. He has trouble staying awake during the day and while driving even though he gets "8 hours" of sleep / night.

What is wrong?

Back 71

Probably Obstructive Sleep Apnea
- Air flow channels are showing no air flow (not breathing)
- Chest wall is moving a bit (there is effort)

Front 72

What are the effects of Obstructive Sleep Apnea on the heart?

Back 72

- Increased negative intrathoracic pressure from trying to inhale but no air coming in d/t obstruction
- Increases LV transmural pressure and LV afterload
- Also increases venous return, increasing RV preload
- Hypoxia causes PA vasconstriction and pulmonary HTN
- Leads to RV distension and leftward displacement of IV septum during diastole which impairs LV filling and diminishes LV preload and stroke volume

Front 73

What are the effects of Obstructive Sleep Apnea on sympathetic nerve activity?

Back 73

- Symp nerve activity (SNA) increases progressively during apnea because of activation of the peripheral and central chemoreflexes by hypoxia and hypercapnia
- Leads to vasoconstriction and surges in BP, which reaches peak during hyperventilation
- SNA abruptly ceases at onset of breathing
- Also have increased muscle tone (EMG) toward end of apnea in relation to arousals from REM sleep

Front 74

What are the negative effects on the CV system of the hypoxia and consequential sympathetic activation?

Back 74

- Arrhythmias (A. Fib)
- Pulmonary HTN
- Vascular disease and MI
- Worsening heart failure
- Systemic HTN and LV Hypertrophy
- Pro-coagulant state

Front 75

Case: Patient is snoring at night, has history of diabetes, HTN, leg swelling. Wakes up in the night and has to sit up on edge of bed to catch his breath. Has to urinate 5-6x/night.

What is wrong?

Back 75

Central Sleep Apnea
- No air flow and no effort
- Also Cheyne-Stokes breathing (crescendo-decrescendo pattern)

Front 76

What kind of breathing is this? What happens to CO2 levels?

Back 76

Cheyne-Stokes Breathing
- PCO2 of lung blood goes up and down (sine pattern)
- PCO2 of respiratory neurons slightly behind
- Overshoot and undershoot CO2 levels

Front 77

Case: 26 year old med student has been sleepy for many years. Prior to this study he completed a sleep diary confirming he was sleeping at least 8-9 hours every night.

What can we do next to evaluate his sleepiness?

Back 77

Multiple Sleep Latency Test - he may have narcolepsy or other problem

Front 78

What does the mean sleep latency on MSLT tell you?

Back 78

- < 3-6 minutes: narcolepsy
- 6-9 minutes: idiopathic hypersomnia
- 7-13 minutes: obstructive sleep apnea
- >10 minutes: normal

Front 79

How common is narcolepsy?

Back 79

Affects 0.03%-0.1% of general population

Front 80

What hormone is commonly missing in patients with narcolepsy?

Back 80

Orexin (aka hypocretin) - involved in controlling sleepiness, when you don't have this you are more likely to have narcolepsy

Front 81

What genetic relationships are there with narcolepsy?

Back 81

- Familial clustering occurs in about 10% of cases
- Most monozygotic twins are discordant

Front 82

What environmental factors are possibly involved in narcolepsy?

Back 82

- Unknown antigen binding w/ HLA DQB1*0602
- Head trauma, virus, toxins
- Sleep deprivation, change in sleep / wake cycle

Front 83

What does these actigraphy results show?

Back 83

College student? Going to bed at 4 am and waking up at noon and taking naps during the day

Front 84

What does these actigraphy results show?

Back 84

Marching through day, non-24 hour sleep
- Could be patient who is ocularly blind
- Ocular nerve communicates w/ superchiasmatic nucleus to tell us when to be awake and asleep

Front 85

What does these actigraphy results show?

Back 85

Chaos - 3rd shift sleep patterns are often all over the place

Front 86

What do these results show?

Back 86

REM sleep but limb leads are very active (lack of atonia) = REM behavior disorder

Front 87

What do these results show?

Back 87

Onset of Night Terror
- Spontaneous attack during stage 3 of NREM sleep
- 2 seconds of diffuse hyper-synchronous high voltage delta wave arousal
- Brief EEG delta discharge immediately preceding the clinical episode
- Increased HR (shown from EKG)

Front 88

What does parasomnia mean?

Back 88

Dissociated sleep states which are partial arousals during the transitions between wakefulness and NREM sleep, or wakefulness and REM sleep.

Front 89

What happens during NREM parasomnias?

Back 89

- Sleep walking
- Sleep talking
- Sleep related eating
- Confusional arousal
- Night terrors

Front 90

What happens during REM parasomnias?

Back 90

- Nightmares
- Sleep paralysis
- REM behavior disorder

Front 91

When do nightmares and night terrors occur?

Back 91

- Nightmare: REM
- Night Terror: NREM

Front 92

Do you awake from nightmares and night terrors?

Back 92

- Nightmare: REM, scary dream awakens person
- Night Terror: NREM, person awakes only partially, if it all

Front 93

When do nightmares and night terrors occur?

Back 93

- Nightmare: REM, last hours of the night
- Night Terror: NREM, one to four hours after falling asleep

Front 94

What are the actions of someone experiencing a nightmare vs night terror?

Back 94

- Nightmare: REM, person may cry and is afraid
- Night Terror: NREM, child sits up, thrashes, and may struggle w/ caregiver, may scream, cry or talk aloud, eyes may be staring ahead w/ heart racing

Front 95

What is the awareness of others in nightmares and night terrors?

Back 95

- Nightmare: REM, aware of others
- Night Terror: NREM, not very aware of others

Front 96

Do people go back to sleep after nightmares vs night terrors?

Back 96

- Nightmare: REM, may have trouble going back to sleep
- Night Terror: often goes back to sleep w/o fully awakening

Front 97

What is the memory of nightmares vs night terrors?

Back 97

- Nightmare: REM, often remembers dream and may want to talk about it
- Night Terror: no memory of dream, or of waking up, screaming, or thrashing

Front 98

Nightmares:
- Type of sleep?
- Awaken?
- When?
- Actions?
- Awareness of others?
- Ability to sleep after?
- Memory?

Back 98

- REM
- Awakens them
- Last 4 hours of night
- May cry and is afraid
- Aware of others
- May have trouble falling back asleep
- Often remembers dream and may want to talk about it

Front 99

Night terrors:
- Type of sleep?
- Awaken?
- When?
- Actions?
- Awareness of others?
- Ability to sleep after?
- Memory?

Back 99

- NREM
- If they awake, only partially if at all
- After 1-4 hours of sleep
- Sit up, thrash, struggle w/ caregiver, scream, cry, talk aloud, eyes may stare ahead w/ heart racing
- Not aware of others
- Go back to sleep w/o fully awakening
- No memory of dream, waking up, screaming, or thrashing

Front 100

Which of the following conditions is bet evaluated w/ a polysomnogram?
- Nightmares
- Obstructive sleep apnea
- Restless leg syndrome
- Delayed sleep phase syndrome

Back 100

Obstructive sleep apnea syndrome

Front 101

How do you best evaluate Obstructive sleep apnea syndrome?

Back 101

Polysomnogram

Front 102

How do you best evaluate a REM behavior disorder?

Back 102

Polysomnogram

Front 103

If patient is going to bed at sundown, what syndrome do they have?

Back 103

Advanced sleep phase syndrome