3- Sleep Flashcards
What is polysomnography
An intensive study of a sleeping person involving simultaneous monitoring and recording of various physiological responses of the sleeper during the course of the night.
Ways of measuring sleep
EEG, EMG, EOG, heart rate, body temp, self reports and video monitoring
EMG Electromyograph
Detect, amplifies and records electrical activity of the muscles
EOG Electrooculargraph
Detect, amplifies and records electrical activity of the eye (surrounding muscles) and eye movement
What do heart rate and core body temperature do as we sleep?
Both heart rate and body temp drop as we progressively drift into deeper and deeper sleep
e.g. body temp can drop by more than 1 degree while we are asleep
Define sleep
Regularly occurring ASC characterised by a loss of conscious awareness.
What does the galvanic skin response record?
A physiological response indicator – detects and records the electrical conductivity of the skin (sweat!)
What happens with GSR as we go through NWC: encountering something, and relaxing, and ASC: taking stimulants, or sleeping
Normal Waking Consciousness
When we experience/encounter something, we tend to increase our GSR – e.g. think about what happens when you are nervous (a strong emotional response)
• GSR tend to decrease when we are relaxed in NWC
Altered State of Consciousness
– GSR can increase in some ASC, such as taking stimulants,
– GSR can decrease in other ASC, such as sleeping
What does video monitoring capture/record
Recorded in real time and allows other responses to be analysed at a later time, therefore it can record:
Levels of alertness
Movement in the night
How long it takes a person to go to sleep
What are self reports in relation to sleep studies, and what is the main type?
Commonly used in sleep studies, particularly sleep diaries or sleep logs.
Sleep diary
a self reported record of an individual’s sleep and waking time activities, usually over a period of several weeks
How long is a sleep cycle (approx) and how many times do you go through them in a 8hour sleeping period
Generally a complete sleep cycle lasts for about 80-120 minutes and we go through the cycle approx.
4-5 times during an 8hrs of sleep per each night
What is frequency in relation to an EEG?
A term used to describe the number of brain waves
What is amplitude in relation to a EEG?
A term used to describe the intensity of the brain waves and is estimated by the size of the brain waves
Peaks (high points) troughs (low points)
Stage of sleep
NREM:1,2,3,4 and REM
What is NREM sleep
(Non, Rapid, Eye, Movement) Approx. 80% of our sleep time is spent is NREM sleep & typically the first half of the night has more NREM sleep than the second half of the night
During NREM sleep the brain is active, but not as active as during REM sleep or during NWC
Researchers have proposed that NREM sleep may be the time when the body recovers, repairing body tissue, removing waste products and replenishing neurotransmitters that are vital to communication b/w neurons
NREM stage 1
Severity of sleep and duration
Physiological changes
Brainwaves
Severity of sleep and duration Very light sleep if woken it may seem like you weren't asleep at all, lasts about 5-10 minutes Physiological changes: -decrease in heart rate -decrease in respiration -decrease in body temp -decrease in muscle tension Brainwaves: alpha waves are replaced by theta waves which have a mixture of high and low amplitude, and hypnotic jerk occurs when body goes into relaxation
What is a Hypnotic Jerk
A spasm or jerking of body parts due to muscle relaxation, this occurs in stage one of NREM
NREM stage 2
Severity of sleep and duration
Physiological changes
Brainwaves
Light stage of sleep, last 10-20 minutes.
Physiological changes:
heart rate slower, blood pressure and temp fall, less body movements,
Brainwaves
theata waves, lower in frequency higher in amplitude, sleep spindles occur (sudden bust in frequency), K-complex (high amplitude in results to an arousing stimulus)
What is a K-complex
An EEG pattern that occurs in Stage 2 of NREM and is characterised of low frequency, slightly higher amplitude waves
-occurs in response to a arousing stimuli e.g door slamming
What is a Sleep Spindle
Brief bursts of higher frequency waves that occurs in stage 2
- It lasts about 1 second
- It indicates a person is truly asleep
NREM stage 3
Severity of sleep and duration
Physiological changes
Brainwaves
Severity of sleep and duration:
Moderately deep sleep, lasts about 10 minutes
Physiological changes:
-heart rate, blood pressure & body temp continue to drop
-breathing continues to be slow and steady
-become extremely relaxed
Brainwaves:
Delta waves make up about 20-50% of the brain waves recorded during stage 3, being slow, large, regular brain waves. Delta waves are lower in frequency & higher in amplitude.
What is Slow Wave Sleep(SWS) ?
It occurs in stages 3&4 as there is a drop in frequency (no. of waves).
- Generally, we begin Slow Wave Sleep within an hour of falling asleep.
- We remain in SWS for about 30 min
NREM stage 4
Severity of sleep and duration
Physiological changes
Brainwaves
Severity of sleep and duration:
Very deep sleep(“out like a light” “sleeping like a log”), lasts up to 20 minutes.
Physiological changes:
Similar to those in stage 3, muscles completely relax and we barely move
Brainwaves:
Delta waves dominate & are even slower and larger than in stage 3
Note:
A person is very hard to wake, however if woken a person can take up to 10 minutes to orientate themselves, this is know a Sleep Inertia
What is sleep inertia/drunkenness
The phenomena that occurs when a person is woken in stage 3/4 of sleep, that causes approximately 10 minutes to orientate themselves.
