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sleep - Coggle Diagram
sleep
CIRCADIAN SLEEP DISORDERS
Delayed Sleep Phase Syndrome (DSPS)
a sleep disorder where the circadian rhythm is pushed later causing people to go to sleep and wake up later than usual
the delay is usually for two or more hours
eg. instead of sleeping from 10:00pm-6:00am, a person sleeps at 2:00am-10:00am
eg. changes to the adolescent sleep-wake cycle
melatonin release delayed by approximately 2 hours in adolescents
if this persists and impairs daily functioning it can lead to DSPS
environmental cues occur at normal times, but they do not match with interal cues (ie. meltaonin release) and or social factors
involves a persistent pattern of sleep disruption due to a mismatch between the circadian rhythm and the sleep-wake cycle required
causes:
intrinsic/internal/biological: age, hormones etc
extrinsic/external/social: shift work, jet lag etc.
Advanced Sleep Phase Disorder (ASPD)
could be due to age-related deteroriation of SCN, a reduction in melatonin production or earlier melatonin release
a sleep disorder where the circadian rhythm shifts earlier causing people to go to sleep and wake up earlier than usual
only a small percentage of elderly people affected
eg. instead of sleep schedule from 10:00pm-6:00am, a person may sleep from 8:00pm-4:00am
shift work
involves working in hours outside of normal working hours
disrupts the normal circadian rhythms due to being awake when melatonin is high
eg. night, early morning or rotating shifts
shift workers sleep 2 hours less than the average worker (sleep deprivation)
shift workers must overide their natural circadian rhythms. if it starts impairing daily functioning, then it may develop into shift work disorder
TREATMENT: bright light therapy
involves regular, timed exposure to intense but safe amoutns of light to resychronise a person's sleep-wake cycle with external cues
time of day, intensity of light and treatment time must be correct, natural or artificial light, multiple session required
DSPS (adolescence)
features are later sleep onset and waking times
exposure to bright light early in the morning to prevent melatonin release, and shift the circadian rhythm earlier, so they go to sleep and wake up earlier
graudally (and consistently) adjust bedtime to make it earlier each night
bright light detected by eyes -> activates SCN -> message sent to pineal gland -> decrease melatonin release -> person feels more alert
ASPD (elderly)
features are earlier sleep onset and waking times
early evening exposure to bright light prevent the release of melatonin and delay sleep onset so that the person will be sleepier later and wake up later
shift work disorder
exposure to bright light before work shift to prevent melatonin release and increase alertedness during the shift
brings melatonin release to an earlier time (during the day). around bright light in the morning when work finishes
SLEEP DEPRIVATION
Total sleep deprivation
EFFECTS
AFFECTIVE:
Sleep deprivation
negative effects eg. sad, irritable
amplified emotional responses
Alcohol consumption
Positive & negative effects eg. happy, excited sad, angry
COGNITIVE
impaired problem solving and deicision making
Impaired memory ability, logic and reasoning
Slower processing speed
illogical thoughts
Decreased performance on cognitive tasks
involves not having any sleep at all over a short-term or long-term period
In victoria, the legal BAC limit for driving a car is under 0.05%
17-19 hours awake/without sleep (partial sleep deprivation) = BAC of 0.05
24 hours awake/without sleep (total sleep deprivation) = BAC of 0.10
Blood alcohol concentration (BAC) is the percentage of alcohol in the bloodstream
Partial sleep deprivation
EFFECTS
COGNITIVE
lapses in attention, inability to maintain prolonged concentration,
Impaired problem solving, decision making, errors in judgement (pre-frontal lobe activity is dampened)
irrational thinking
impaired learning and memory
More specifically: performance on complex and difficult tasks are not affected, but performance on short or monotonous tasks are affected
AFFECTIVE
Amplified emotional responses
: emotional reactions quickens be more intense or exaggerated and out of characters
Mood changes:
irritable, short tempered, loss of motivation, sadness
Poorer emotion perception:
inaccurate emotional judgement
Become overwhelmed when confronted with stressors
**REM dep= that emotional reactivity is more likely to occur with REM sleep deprivation (link is unclear)
BEHAVIOURAL
Sleep intertia; feels groggy, partly awake and disoriented as they transition toward full allertness (few min)
Diminished social functioning and impaired control of behaviour
Reduced motor control and heightened clumsiness, contributing to higher rates of accidents and injuries
Slower reaction time
Increased likelihood of engaging in risk-taking behaviour
involves having less sleep (either quality or quantity) than what is normally required
it may occur periodically/persistantly over the short-term or long-term
with successive nights, sleep debt can accumulate and sleep deprivation effects can multiply
Long-term (chronic) sleep deprivation places the individual at a greater risk of a range of diseases and health problems
EG. obesity, diabetes and various cardiovascular diseases
a state caused by inadequate quantity or quality of sleep, either voluntary or involuntary
sleep
quantity
refers to the amount of sleep - measured objectively using time
Sleep
quality
refers to how well we feel we have slept - it relies on subjective self-report measures
SLEEP AS A PSYCHOLOGICAL CONSTRUCT
Consciousness
the awareness of our own thoughts, feelings and perceptions (internal events) and our surroundings (external events) at any given moment
referred to as a psychological construct: a hypothetical concept that are thought to exist but can't be directly observed or measured
Consciousness ranges along a continuum or scale from total awareness to complete lack lack awareness
State of Consciousness:
refers to our level of awareness of our internal state and external environment
two types: normal waking consciousness (NWC) and altered state of consciousness (ASC)
two types
NWC
a state experienced when you are awake and aware of internal events (thoughts, feelings & perceptions)
and the external environment (talking with a friend, reading a book)
ASC
a state that is distincting different from normal WC
induced eg. aclohol-induced state, meditative state
naturally occuring eg. sleep
Sleep
a naturally occuring ASC, characterised by a reduction in awareness and responsiveness to external surroundings
psychological characteristics include innacurate time perception, lack of self-control e.g sleepwalking; lack of control over thoughts e.g dreaming
measuring sleep
SUBJECTIVE MEASURES
relies on participant's honesty
based on personal opinions and interpretation and is therefore have more likely to be biased
often used in conjunction with objective measures to verify validity of sleep phenomena
can provide information about mental process and behaviours that are difficult to measure
Sleep Diary
self-reported record of an individual's sleep & waking time activities.
(-): subjective as it relies on personal judgements/honesty, relies on good memory
(+): insights into thoughts feelings, can find behaviour patterns that may be affecting sleep
eg. quantity of sleep, time taken to fall asleep, how many time they wake up, how refreshed they feel, content of dreams, caffeine consumption, stress levels etc.
Video Monitoring
infrared cameras allows footage of behavioural observations to be taped in the dark without disturbing the participant
e.g observing rolling, restless legs, breathing patterns + sleepwalking, how many times they woke up, how refreshed they feel, content of dreams, caffeine consumption, stress levels etc.
(+): can be used in natural environments, can re-watch footage
(-): subjective as researcher must interpret behaviour; doesn't show what is going on with the participant internally; may miss events if there is a time delay or researcher looks away
OBJECTIVE MEASURES
EEG
an instrument that detects, amplifies and records the electrical data of the brain, measured by brainwaves
brainwaves patterns vary in frequency and amplitude
beta -> high frequency -> low amplitude -> NWC (alert state)
alpha -> med-high frequency -> low-med amplitude -> relaxing state (eg. meditating)
theta -> medium frequency -> mixture of low and high amplitude -> early stages of sleep
delta -> low frequency -> high amplitude -> deep sleep
measurable changes in physiological responses provide researchers w info about how bodily functions throughout sleep
not subject to personal opinions or interpretations by the researcher
(+): data is easy to measure and compare, minimal interpretations, thus minimising bias, more accurate and reliable data, allows for replication
EOG
an instrument that detects, amplifies & records the electrical activity of muscles responsible for eye movement
During NREM - EOG would show low levels of electrical activity due to minimal eye movements
During REM - EOG would show high levels of electrical activity due to jerky eye movement
EMG
it indicated changes in muslce activity (movement) and muscle tone (tension)
During NREM - EMG would show low levels of electrical activity. However, if muslce spasms or sleepwalking occurs, electrical activity would increase
an instrument that detects, amplifies & records the electrical activity of muscles in the body
During REM - EMG would show very low levels of electrical activity due to being in a state of virtual muscle paralysis
NREM sleep
Brain & body activity: less active brain, body can move (movement decreases in deeper stages)
Dreaming: less, vivid dreams, rarely remembered
Ease of Waking: becomes harder to wake as sleep gets deeper
Proportion of Sleep: about 75-80% of a sleep episode
Changes across the night: time spent in NREM decreases throughout the night
Purpose: replenishes the body
Stages: Three stages; NREM 1, NREM 2 & NREM 3
Purpose: replenish the body
REM sleep
Purpose: replenish the mind
Brain and body activity: highly active brain, body in cataplexy
Dreaming: vivid dreams, often remembered
Ease of waking: relatively easy to wake
Proportion of sleep: about 20-25% of a sleep episode
Changes across the night: time spent in REM increases throughout the night
Total Awareness
Selective attention (controlled processes)
Divided attention (automatic processes)
Daydreaming
Meditation
Hypnosis
Alcohol Induced State
Asleep
Anaesthetised
Unconscious (coma)
Complete Lack of Awareness
SLEEP HYGIENE
ZEITGEBERS
EATING AND DRINKING PATTERNS
WHAT WE EAT/DRINK
Spicy foods increase body temperature and metabolic processes which impair sleep
caffeine (stimulant) impairs sleep quality, quantity and timing
Alcohol (depressant) lowers quality of sleep
Foods high in sugar and fat stimulate digestive activity and reduce sleep quality and quantity
WHEN WE EAT.DRINK
Avoid caffeine, alcohol, spicy foods and foods high in sugar and fat fater lunch
HOW MUCH WE EAT/DRINK
Going to sleep hungry or feeling overly full can impair sleep patterns
these cues help to promote sleepiness and wakefulness at appropriate times
are external, environmental cues that help to regulate and or resynchornise the body's circadian rhythm
LIGHT
blue light is released naturally (from sun) and artificially (from devices)
light is the primrary zeitgeber for human circadian rhythms
It signals the SCN to send an inhibitory message to the pineal gland to reduce melatonin release. This will reduce feelings of tiredness
there are many different types of zeitgebers, including light, temperature, eating and drinking patterns
TEMP
Improves the quantity and quality of sleep
A decreased in body temp is linked with an increase in melatonin and an increase in feelings of sleepiness . i.e cooler room temp
air temp (i.e external heat) can act as a zeitgeber to help the body get ready for sleep
The hypothalamus (including SCN) regulates body temp
Sleep-related habits/behaviours that improve the timing, quality and/or quantity of sleep
SLEEP PATTERNS ACROSS A LIFESPAN
possible changes
awakenings during sleep increase from adulthood to old age
amount of N3 sleep decreases, replaced mostly N2 sleep
total sleep amount decreases
sleep efficiency (the percentage of the time in bed that is spent asleep) reduces
a circadian phases delay occurs during adolescne (preference for going to sleep later)
proportion of REM sleep decreasess significantly from birth until 2 years old
varying ages
infant
16 hours sleep, 50% NREM and 50% REM sleep
rapid brain development so no more REM sleeep required, circadian rhythm not yet developed so sleep patterns irregular and sleep onset occurs through REM
child
10-12 hours, 75% NREM and 25% REM sleep
brain development slows down and steadies, half of NREM sleep is in stage 4 due to rapid physical growth
adolescent
8-10 hours, 80% NREM and 20% REM sleep
less time spent in N3 and more in N2, require more sleep than adult due to learning and phsycial development, delayed response of melatonin (approx 2 years)
adult
7-8 hours, 80% NREM and 20% REM sleep
N3 continues to decrease throughout childhood, sleep-wake cycle shift can return to an easuer release of melatonin in early adulthood
elderly
5-7 hours, 80% NREM and 20% REM sleep
much less time spent in N3 (more in N1 and N2), more awakenings, tend to become sleepier earlier and wake up earlier (ie. circadian rhythms)
SLEEP WAKE PATTERNS
Biological Rhythms:
a natural, cyclical rhythms our body follows for us to perform a variety of functions
influenced by internal factors (e.g hormones) & external factors (e.g light, noise, travel)
Night
Light-sensitive neurons in retinas of the eyes detect incoming light
Messages then sent to the suprachiasmatic nucleus about amount of light in the environment
If there is little/no light, SCN sends excitatory neural messages to the pineal gland to release more melatonin ,thus inducing sleepiness
Daytime
Light-sensitive neurons in retinas of the eyes detect incoming light
Messages then sent to the suprachiasmatic nucleus about amount of light in the environment
If there is more light, SCN sends inhibitory neural messages to the pineal gland to release less melatonin, thus increasing alertness/wakefulness
CIRCADIAN RHYTHMS
involves changes in bodily functions/activities that occurs as part of a cycle with a duration of
about 24
hours (e.g sleep wake cycle)
sleep-wake cycle is
endogenous
(based on internal biological factors ie. our internal body clock**
but it influenced by
zeitgebers
(environmental time cues) such as light, external temp, noise and food**
BIOLOGICAL STRUCTURES
SCN
part of the hypothalamus
relies on internal & external cues
acts like an internal body clock to regulate sleep-wake cycles
Pineal Gland
produces & releases melatonin
messages from the SCN determine when melatonin is released
Melatonin
hormone that causes sleepiness
released in low-light conditions to cause sleepiness
ULTRADIAN RHYTHMS
involves changes in bodilty functions or activities that occur as part of a cycle
shorter than 24h
(e.g heartbeat, hunger and eating behaviour, secretion of different type of hormones, and sleep cycles
Sleep Cycles
each cycle typically lasts about 90 minutes & includes progression through stages of NREM sleep (from light to deep sleep) followed by REM sleep
a sleep cycle is considered an ultradian rhythm because it is repeating pattern that occurs multiple times within a 24 hour period
are repeating pattern of different stages of sleep that the brain and body go through during a period of sleep
STAGES OF SLEEP
REM
known as paradoxial sleep (internally brain/body is active but externally body still & inactive)
makes up about 20% of total sleep
first period of REM may only be a few minutes but final period may last up to 1 hours
lighter the stage of sleep, can be easily woken and if woken, will probably report dreaming
NREM 1
:
drift in and out of sleep, but still aware of some sounds in the environment
may experience feelings of falling, floating or a hypnic jerk
if woekn, sleeper will not feel as if they were sleeping
NREM 2:
when 'true' sleep commences, but still receptive to external stimuli (e.g loud noises)
accounts for 50% of the total sleep time
sleeper will stil deny being asleep, fairly easy to wake
NREM 3:
(delta sleep)
deepest stage of sleep with lowest levels of conscious awareness
very difficult to wake someone up from this stage
if woken, sleep will be confused & may not recall what woke them
sleep disturbances usually occur in this stage, e.g sleepwalking, night terrors
Sleep Cycles are represented on a hypnogram
NREM 1
NREM 2
NREM 3
NREM 2
REM
NREM 2
NREM 3
NREM 2
REM
NREM 2
Looking for: sleep onset, percentage of REM
sleep, percentage NREM3, awakening