7B- techniques used to measure sleep Flashcards
polysomnography
a multi parameter sleep study used as a diagnostic tool in sleep medicine
electroencephalography EEG
a technique that Detects, Amplifies and Records the Electrical activity of the brain.
DARE
beta waves
frequency: highest
amplitude: lowest
normal waking consciousness, awake, alert and focused, high environmental stimulation and the brain works on several things at once
frequency
how much activity is occurring every second
amplitude
the intensity or strength of brain waves
alpha waves
frequency: high
amplitude: low
lower alertness, awake but relaxed, quiet and calm, drowsy, eyes closed and low environmental stimulation
theta waves
frequency: low
amplitude: high
low alertness, light sleep, senses withdrawn from the external environment, deep meditation
delta waves
frequency: lowest
amplitude: highest
lowest alertness, deep N3 sleep, dreamless sleep
electromyography EMG
a technique that Detects, Amplifies and Records the Electrical activity of the skeletal muscles
DARE
electrooculography EOG
a technique that detects, amplifies and records the electrical activity of the muscles controlling the eyes
dare
sleep diaries
a subjective self report tool used by a person to track their own sleep and wake patterns
video monitoring
a sleep study tool used to collect qualitative visual and audio information about a person’s sleep
what is the importance of measuring sleep
there are different techniques for measuring sleep based on objective physiological changes in the activity of the body, observations and subjective reports. these techniques can allow a person to detect and record sleep features. it is useful to diagnose sleep disorders, track how sleep is affected by various factors like medication or even improving performance of athletes. several techniques are combined to form a sleep study called polysomnography
what do sleep techniques do?
detect, amplify and record the electrical activity of a part of the body
what does EEG’s do
detect, amplify and record the electrical activity of the brain
attached to a scalp/through a cap or headset
electrodes detect the synchronised electrical impulses of neurons that communication at the surface of the cortex.
wires transmit the data to the EEG which amplifies the signals to a readable level, sending them to a computer, recorded as brain wave patterns and interpreted by a specialist
brain wave recordings are summaries of the activity of thousands of neurons
EEG’s may be used to identify a particular stage or abnormal brain activity that differs from teh expected
what are the 4 brain wave types
beta, alpha, theta and delta
in decreasing order of frequency, increasing order of amplitude.
what does the frequency of brain waves indicate
speed of brain waves or how much is occurring every second
visually identified in a brain wave recording according to how close together the waves are the number of times the wave repeats in a 1 second interval
what does slow frequency brain waves indicate
the are prevalent when we are tired, relaxed or asleep
what does faster frequency brain waves indicate
they are prevalent when we are awake and alert
what does the amplitude of brain waves indicate
the intensity or strength of the brain wave, or how many neurons are firing at teh same time together.
visually identified according to the height of the brain waves or the (vertical) distance between the peaks and troughs
what does a greater amplitude indicate
higher peaks and lower troughts indicate more synchronised brain activity from multiple neurons working on a similar task such as sleep
what does a lower amplitude indicate
groups of neurons are working on different tasks such as driving a car (watching the road with the eyes, keeping the car straight with firm hands on the wheel)
what are beta waves
frequency: highest
amplitude: lowest
state: NWC, awake, alert and focused, high environmental stimulation, brain is working on several things at once
what are alpha waves
frequency: high
amplitude: low
state: lower alertness, awake but relaxed, quiet and calm, drowsy, eyes closed, low environmental stimulation
what are theta waves
frequency: low
amplitude: high
state: low alertness, light sleep, senses withdrawn from external environment, deep meditation
what are delta waves
frequency: lowest
amplitude: highest
state: lowest alertness, deep N3 sleep, dreamless sleep
what do EMG’s do
detect, amplify and record the electrical activity of the skeletal muscles
electrodes are attached to the surface of the skin- jaw and sometimes legs or other body parts
may measure muscle tension which indicate sleep stages and type of sleep experienced
EMG’s- more muscle tension
more muscle tension indicates greater alertness, so as a person drifts into deeper sleep, muscle movement decreases
what do EMG’s detect during REM sleep
no muscle movement.
what else can EMG’s detect
abnormal moving- tossing and turning
teeth grinding
leg movements- sleep disorder (periodic limb movement disorder or sleep bruxism)
what do EOG’s do
detect, amplify and record electrical activity of the muscles controlling the eyes
electrodes are attached to the surface of the skin, around the sides of each eye
may be used to determine onset of sleep as well as when the stages and type of sleep occur
eye movement decreases as you progress into deeper sleep and when you experience REM sleep your eye movement increases
Describe the overall pattern of the changes to brain wave frequency and amplitude as a person drifts into deeper sleep.
As a person drifts into deeper sleep, the frequency of their brain waves decreases and the amplitude of their brain waves increases.
Describe the expected output of an EMG when a person is in deep N3 sleep.
During deep N3 sleep, an EMG would typically detect, amplify and record a low level of electrical activity of the muscles, indicating low amounts of muscle movement.
Describe the expected output of an EOG when a person is in REM sleep.
In REM sleep, an EOG would typically detect, amplify and record a high level of electrical activity of the muscles controlling the eyes, indicating high amounts of eye movement.
what are sleep diaries
subjective, self report tool used by a person to track their own sleep and wake patterns
aim to identify any patterns or habits that may be leading to sleep trouble and can provide a sleep specialist with a personal and subjective account of the quality and quantity of sleep experienced
what do sleep diaries typically consist of
time of sleep onset
waking time
how they felt upon waking
disturbances to sleep- periods of waking
unusual behaviours
anything that could affect a person’s sleep patterns- caffeine intake etc
how can sleep diaries be used effectively
as disturbed sleep can cause a mental health disorder, a sleep specialist can interpret the sleep diary and can pair this with information from objective measures such as changes detected by an EMG, EEG or EOG
what is video monitoring
collects qualitative visual and audio information about a person’s sleep. it can validate data collected by objective means to show what activity is occuring while a person is asleep. can also be useful for children who have sleep problems and may have trouble verbalising their experience/ too young for a sleep diary. can be used alongside objective measures and sleep diaries to diagnose sleep disorders
Describe why a sleep diary is considered a subjective measure of sleep.
A sleep diary is subjective because it is based on personal interpretation.
list four features of a person’s sleep that may be recorded in a sleep diary.
time of going to sleep
time of waking
how person feels on waking
any disturbances during sleep
any unusual behaviours during sleep
caffeine intake
any naps taken
exercise completed during the day.
List four things that video monitoring might detect during a sleep study.
what activity is occurring while a person is asleep
sleeping positions
specific movements
laboured breathing
sleep talking
teeth grinding.
Provide one similarity and one difference between an EOG and an EMG.
Similarity: An EOG and EMG both detect, amplify and record the electrical activity of muscles.
Difference: An EOG detects, amplifies and records the electrical activity of the muscles controlling the eyes specifically, whereas an EMG detects, amplified and records the electrical activity of muscles elsewhere in the body such as the legs.
Explain why video monitoring is useful alongside other measures during a sleep study.
Video monitoring can be used to show what activity is occurring during sleep, in order to validate information from other measures such as EMGs, EEGs and EOGs.
