Sleep Flashcards
1
Q
Sleep
A
- Complex behavioral and physiologic process
- Reversible state of perceptual disengagement
- Usually-closed eyes, postural recumbence
- Divided into 2 distinct states
- NREM (Rhythmic sleep)
- REM
- Brain is the essential organ which regulates the sleep/wake cycle
2
Q
What defines sleep onset?
A
-
No single measure can tell us.
- EEG (electroencephalogram) and self-perception may be different…
-
Distinct electrophysiologic pattern
- gradual reduction in muscle tone
- slow rolling eye movements
- reduction in alpha and increase in theta
-
Behavioral Concomitants:
- reduced sensory processing
- tapping experiments: automatic behavior persists
- visual and auditory responsiveness diminshed
- olfactory response: not a good sentinel system
- memory: transition to sleep causes impairment
3
Q
Physiology of Sleep
A
- Adults require 7-8 hours
- Adolescents need about 9 hours
- Elderly need stable amounts
- As people age, their sleep patterns change
- With aging, the sleep efficiency diminishes due to increase of stages 1 and 2 sleep and decrease in REM sleep
- Genetics can influence natural short and long sleepers (only need 4 hours or need 8-9 hours)
4
Q
Sleep stages
A
We measure this through an EEG (electro-encephalogram)
- Electrodes are attached to scalp and measure electrical activity of brain when patients are sleeping to see when they enter stages of sleep
- NREM: non-rapid eye movement (50-60% of total sleep time)
- REM: rapid-eye movement
5
Q
NREM: non-rapid eye movement (50-60% of total sleep time)
A
- As we go from stage I to stage IV, it is harder to arouse the patients.
- increasing arousal threshold and slowing of the cortical EEG
- As stages increase, the muscles get more and more relaxed.
6
Q
EEG Lines
A
- Top 4 lines are brain
- 5th line is muscle movement
- Bottom 2 lines are eye movement
7
Q
Stage I: onset of sleep / short stage
A
- Easy to arouse
- EEG: low voltage theta/alpha waves, mild eye movements, higher emg movements
- •very short stage
- ~7-8 minutes
- Easy to arouse
- Lower voltage, higher EMG movements, and mild eye movements
8
Q
Stage II: light sleep (majority of NREM is in health people is in this stage)
A
- EEG: sleep spindles and K complexes
- •Where a person spends the majority of sleep; ~45%
- Muscles begin to relax, slighter deep level
- Sleep spindles and K complexes
9
Q
Stage III: deeper
A
- EEG: delta waves
- •“slow wave” sleep stages
- Even more relaxed
- Even more difficult to arouse
- High voltage slower waves
10
Q
Stage IV: deep sleep/dream sleep
A
- Dreaming starts in stage four and continues in REM sleep
- EEG changes: High-amplitude, slow waves
11
Q
REM: rapid-eye movement
A
- Also known as paradoxical sleep
- Inc brain metabolism during this phase than when we are awake
- EEG changes: Low-amplitude, mixed-frequency EEG
- EOG: bursts of rapid eye movement
-
Our body enters a stage of atonia so EMG is absent in nearly all skeletal muscles
- Inhibition of spinal motor neurons by brainstem mechanisms
- REM sleep is characterized by a low-amplitude, mixed-frequency EEG similar to that of NREM stage N1 sleep. The EOG shows bursts of rapid eye movements similar to those seen during eyes-open wakefulness. EMG activity is absent in nearly all skeletal muscles, reflecting the brainstem-mediated muscle atonia that is characteristic of REM sleep.
12
Q
Objective measure :Gold standard is polysomnography
A
- Look at apnea-hypopnea index with synchronous periods of oxygen desaturation
- Overnight measurement of sleep stages, quality and physiology, EKG, respiration and oxygen, and muscle movements
- EEG: electrical activity of brain
- EOG: eye movement activity
- EMG: movement on chin, neck and leg
- EKG
- Chest wall movement and RR: airflow out of nose and mouth
- CO2, Pulse Ox
- Audio/video- to see what they do during sleep (snoring, gasping, moving)
13
Q
Objective Tests for Measuring Sleep: Multiple Sleep Latency Test (MSLT)
A
Five 20 minute nap opportunities measuring minutes to sleep-onset and REM-onset
14
Q
Objective Tests for Measuring Sleep: Maintenance of Wakefulness Test (MWT)
A
Four 40-minute trials measuring the ability to remain awake
15
Q
Subjective test: Epworth Sleepiness Scale
A
- Epworth Sleepiness Scale
- Chance of dozing while:
- Watching TV
- Sitting inactive in a public place (e.g. a theater or a meeting)
- Sitting and reading
- As a passenger in a car for an hour without a break
- Lying down to rest in the afternoon when circumstances permit
- Sitting and talking to someone
- Sitting quietly after a lunch without alcohol
- In a car, while stopped for a few minutes in traffic
- Chance of dozing
- 0 = would never doze
- 1 = slight chance of dozing
- 2 = moderate chance of dozing
- 3 = high chance of dozing
- 0-9 is normal, 10 and above is abnormal
- Abnormal scores mean you’ll be ordering a sleep study and/or a referral to a sleep MD…
- Chance of dozing while:
16
Q
What is normal sleep
A
“when we sleep and fall into sleep time, our brain tells our body that our hypoxic drive can decrease and ventilatory response is diminished and we are still ok”
- Input from the behavioral control system decreases → the hypoxic drive to breathe is reduced → the ventilatory response to partial pressure of carbon dioxide in arterial blood is diminished
17
Q
With age in healthy pts, both episodes tend to increase which is normal
A
- Apnea
- hypopnea
18
Q
Sleep Disturbances/Disorders
A
- 50-70 million Americans suffer from chronic disorder of sleep and wakefulness
