Sleep Flashcards
What is consciousness
the level of awareness the individual has of their thoughts, feelings, perceptions and existence
2 types of consciousness
- normal waking consciousness
- altered state of consciousness
what is normal waking consciousness
an individual is awake and aware of thoughts, feelings, behaviours
e.g. being awake
what is altered state of consciousness
characteristics are different from normal waking consciousness, in terms of quality of experience and levels of awareness.
types of altered state of consciousness
Induced and naturally occurring
what is naturally occurring altered state of consciousness
a type of consciousness that that occurs without intervention.
e.g. sleep, and daydreaming
what is induced altered state of consciousness
a type of altered state of consciousness that occurs due to purposeful action or aid
e.g. meditation, alcohol, hypnosis
consciousness continuum
a visual representation of the different stages of consciousness that progress from lower levels of awareness to higher levels of awareness.
what is sleep
a regular and naturally occurring altered state if consciousness that involves loss of awareness and disengagement with internal and external stimuli
characteristics of sleep
- a reduced ability to control behaviour
- reduced control over thoughts e.g. we lack control over what we dream about
- less accurate understanding of time
- perseptual and cognitive disfunction
types of sleep
non-rapid eye movement (NREM)
rapid eye movement (REM)
what is NREM sleep
a type of sleep characterised by a lack of rapid eye movement and is subdivided into three stages.
(NREM 1,2,3)
what is REM sleep
a type of sleep characterised by rapid eye movement, high levels of brain activity, and low levels of physical activity
what is a sleep episode
the full duration of time spent asleep. it is made up of multiple repeated cycles of REM and NREM sleep
what is a sleep cycle
an approximately 90-minute-period that repeats during a sleep episode in which an individual progresses through stages of REM and NREM sleep
what is a hypnogram
a sleep graph that tracks the proportion of time spent in each stage of sleep, including awakenings, throughout a sleep episode
Characteristics of REM
- sleeper has a highly active brain and a less active body
- sleeper is virtually paralysed during REM sleep - most muscle movement is not possible
- relatively light stage of sleep; despite the muscle
paralysis, the brain is active and sleepers can be woken
fairly easily - Vivid dreaming tends to occur - sleeper frequently recalls dreams
- makes up approximately 20-25% of a sleep
episode for most age groups - The amount of time spent in REM sleep increases as the
sleep episode progresses, with the largest amount of REM
in the sleep cycle occurring immediately before waking
characteristics of NREM sleep
- sleeper has less active brain than normal waking consciousness.
- physical movement is possible - however, movement tends to decrease as NREM stages progress.
- Dreams can occur but they are often non-vivid - sleeper does not frequently recall dreams
- The amount of time spent in NREM sleep is highest during the
first half of a sleep episode. - makes up approximately 75-80% of a sleep episode
- NREM sleep tends to become shorter with each sleep cycle.
characteristics of NREM 1
- sleeper transitions from being awake into a light sleep
- hypnagogic state - feelings of floating or falling
- hypnic jerks/sudden jerks
- sleeper loses awareness of themselves and their surroundings but is still aware of faint sounds in the environment.
- sleeper can be easily woken
characteristics of NREM 2
- sleeper is still in relatively light sleep
- sleepers spend majority of their sleep time in NREM 2
- sleeper is considered “truly” asleep due to their brain waves
characteristics of NREM 3
- deepest sleep
- difficult to wake sleeper
- if sleeper is woken they are likely to be drowsy and disorientated
- sleep walking/talking is likely to occur
measures of consciousness (and sleep)
- the electroencephalograph (EEG)
- the electromyograph (EMG)
- the electro-oculograph (EOG)
- sleep diaries
- video monitoring
which measures of consciousness are objective
- the electroencephalograph (EEG)
- the electromyograph (EMG)
- the electro-oculograph (EOG)
advantages/disadvantages of objective measures of consciousness
provide reliable, unbiased, quantitative data that can indicate someone’s state of consciousness.
do not provide qualitative detail about the personal experience of sleep, such as thoughts or feelings.
changes in physiological responses may be due to factors other than a change in consciousness
which measures of consciousness are subjective
- sleep diaries
- video monitoring
are sleep measures always accurate
no
some techniques can be disruptive, invasive, or require
an individual to sleep in a sleep laboratory.
Changes to an individual’s regular sleep patterns, such as having to record their sleep or having electrodes attached
to their head, can influence the quality and quantity of an individual’s sleep.
what is an Electroencephalograph (EEG)
a device that detects, amplifies, and records the electrical
activity of the brain
how does an electroencephalograph work
a medical professional or researcher attaches electrodes to the
outside of a person’s head.
electrodes detect electrical impulses that are emitted by neurons when they communicate.
the impulses are presented as brain wave patterns.
different brain wave patterns correlate to different states of consciousness.
brain waves in REM sleep
beta
higher frequency and lower amplitude
brain waves in NREM 1
alpha
high frequency (lower than beta) and low amplitude (higher than beta)
brain waves in NREM 2
theta
medium frequency and medium amplitude
can show ‘sleep spindles’ - brief bursts of high frequency waves which sleep researchers identify as the point where a sleeper is truly asleep.
brain waves in NREM 3
delta
low frequency and high amplitude
Strengths of electroencephalography (EEG)
useful for sleep studies or diagnoses of patients with brain damage or a neurological or mental disorder
limitations of electroencephalography (EEG)
measures neural activity underneath a thick and hard skull and
thus is not entirely precise
does not identify functional and dysfunctional brain areas
what is electromyography (EMG)
a device that detects, amplifies, and records the electrical activity of the body’s muscles
how does electromyography work
electrodes are attached to the skin above the muscles under investigation, and the movement and tension of muscles are recorded.
REM sleep = EMG readings show low activity due to low levels
of physiological activity.
NREM sleep = EMG readings show medium/moderate activity, at first, and as stages progress, an EMG is likely to show lower activity as movement is less likely to occur
what is Electro-oculography (EOG)
a device that detects, amplifies, and records the electrical activity of the muscles responsible for eye movement.
how does electro-oculography work
electrodes are attached to the skin above the muscles responsible for eye movement.
REM sleep = EOG is likely to show high activity
NREM sleep = EOG is likely to show low activity.
what are sleep diaries
a record containing self reported descriptions from an individual about their sleeping periods, including an estimated time spent sleeping, and judgement they may have about the quality and nature of their sleep
what information can a sleep diary include
includes quantitative and qualitative info
- duration of sleep
- quality of sleep
- thoughts and feelings before going to sleep
- thoughts and feelings after waking up
- behaviours before going to sleep
- behaviours after waking up
- the number of times sleep was disrupted.
strengths of sleep diaries
they provide qualitative information and therefore are often
extensive in detail and description
limitations of sleep diaries
as the patient is responsible for collecting and reporting the information within a sleep diary, it is subjective and therefore may not be accurate.
What is video monitoring?
the use of camera and audio technologies to record an individual as they sleep.
strengths of video monitoring
provides data specific to the individual to track their sleeping and waking periods, their movements and activities when sleeping, and the sounds they make while sleeping
useful for individuals with sleep disorders, as their behaviors
during sleep can be observed
Limitations of video monitoring
video monitoring is subjective.
e.g. it may be unclear whether an individual seen to be getting out of bed during the night is awake or sleep-walking.
biological rhythms
repeated biological processes that are regulated by internal mechanisms
e.g. blood pressure, body temperature
two types involved in sleep: circadian and ultradian
circadian rhythms
biological and behavioral changes that occur as part of a cycle that lasts around 24 hours
e.g. sleep-wake cycle - involves biological changes
that occur over a 24-hour period
what is the sleep wake cycle
a 24-hour-cycle that is made up of time spent sleeping and time spent awake and alert
ultradian rhythms
biological and behavioural changes that occur in a cycle that lasts less than 24 hours
e.g. sleep cycle - involves changes in physiological activity that repeat in a cyclic manner in less than 24 hours
suprachiasmatic nucleus (SCN)
an area of the hypothalamus that is responsible for regulating
an individual’s sleep-wake patterns
acts as an internal body clock
- made up of 2 nuclei that have approximately 10,000 neurons each and are located above the optic chiasm
how does the SCN regulate the sleep-wake cycle
- the SCN receives information from external and internal cues
- after receiving cues, the SCN sends neural messages to the pineal gland to produce and release melatonin
- the pineal gland releases melatonin into the bloodstream, which promotes feelings of calm and relaxation, therefore promoting sleep
external cues
involve information from the environment
e.g. presence or absence of light
internal cues
involve information that originates within the body
e.g. expression or suppression of particular genes
pineal gland
a gland in the brain responsible for the production and release
of melatonin
melatonin
a hormone released by the pineal gland typically at night time to induce sleep as part of the sleep-wake cycle
- the body produces melatonin naturally and usually in adequate amounts
When is melatonin secreted?
At the onset of darkness in the evening, levels of melatonin
start to rise.
At 8-9pm, melatonin levels should reach a level that starts to induce a sense of calmness, which promotes sleepiness, leading to an individual naturally wanting to induce sleep at around 10 to 11pm.
Melatonin peaks between 2 and 4am, when individuals are typically in the deepest sleep, before gradually declining over
the night and before waking in the morning.
does melatonin directly induce sleep
Melatonin does not directly induce sleep, it promotes a state of calm and relaxation to help make it easier to fall asleep
cortisol
a hormone that is responsible for increasing alertness
and maintaining heightened arousal
- released by adrenal glands to promote wakefullness
Sleep
Neonatal period (1-15 days):
- sleep duration is highest it will ever be in the lifespan
- sleep for 16 hours
- 50% REM, 50% NREM
Sleep
Infancy (3-24 months)
- sleep duration decreases to approximately 13.5 hours
- 35% Rem, 65% NREM
why do neonatals and infants spend so much time in REM
they are experiencing rapid brain development
Sleep
Childhood (2-14 years)
- sleep duration decreases to approximately 11 hours
- 20% REM, 80% NREM
- Time spent in REM sleep reduces as the pace of brain
development steadies. - half of NREM sleep is stage 3
Sleep
Adolescence (14-18 years)
- sleep duration decreases to 9 hours
- remains 20% REM, 80% NREM
- experience a biological delayed sleep onset by 1-2 hours
- time spent in NREM 3 decreases
- time spent in NREM 2 increases
- sleep patterns change due to social factors - school, social commitments
Sleep
Young Adulthood (18-30 years)
- sleep duration decreases to approximately 7.75 hours
- 20% REM, 80% NREM
Sleep
Middle adulthood (30-75 years)
- sleep duration remains at 7-8 hours
- 20% REM, 80% NREM
Sleep
Old age (75+ years)
- sleep duration decreases to approximately 6 hours
- 20% REM, 80% NREM
- experience a biological shift in their sleep cycle - become sleepier earlier and wake up earlier
- lower levels of sleep are attributed to ill health and an increase in prevalence of sleep disorders
sleep deprivation
inadequate quantity and/or quality of sleep
full sleep and partial sleep deprivation
full sleep deprivation
when an individual has no sleep within a 24-hour period
partial sleep deprivation
when an individual sleeps for some duration within a 24-hour-period, but the sleep duration is too short, or the quality of
sleep is poor
- based on an individuals needs (age)
types of effects of sleep deprivation
affective
behavioural
cognitive
define ‘affective’ in terms of sleep deprivation effects
the changes in emotions and emotional responses that arise from sleep deprivation
define ‘behavioural’ in terms of sleep deprivation effects
the changes in actions and the ability to control them that arise from sleep deprivation
define ‘cognitive’ in terms of sleep deprivation effects
the changes in mental processes that arise from sleep deprivation
affective effects of sleep deprivation
- poor emotional regulation; resulting in amplified emotional responses that are out exaggerated
- irritability
- increase in negative emotions
- reduced ability to cope with stress
- reduced empathy towards others
- increase in aggression and impatience
- increase in mood swings
behavioural effects of sleep deprivation
- fatigue
- increased likelihood of engaging in risk-taking behaviours
- slowed reaction time
- reduced efficiency; takes more time to complete tasks
- reduced motor control and heightened clumsiness
- involuntary lapses into microsleeps
cognitive effects of sleep deprivation
- reduced concentration
- impairment of short-term memory
- diminished ability to perform cognitive tasks
- lapses in attention
- impaired decision-making processes and problem-solving abilities
- diminished creativity and ability to utilise abstract thought
- reduced retention of information - impaired learning and memory processes
- irrational and/or illogical thinking
- impaired visual and spatial ability
What is blood alcohol concentration?
a measure of how much alcohol is in a persons blood stream
because alcohol is a depressant drug…
it will slow down the nervous system and decrease alertness, concentration, reflexes, and decision making
a BAC of 0.10 is equal to
cognitive impairments of 24 hours sleep deprivation
a BAC of 0.05 is equal to
cognitive impairments of 17 hours sleep deprivation
Affective effects of BAC compared to sleep deprivation
sleep deprivation usually has a negative effect on a persons emotional state, while alcohol can have a range of emotional effects (in the long term, alcohol is likely to have dulling effects on emotions)
both alter an individual’s emotional state and cause individuals to experience amplified emotional responses
cognitive effects of sleep deprivation compared to BAC
BAC 0.05=17 hours
BAC 0.10=24 hours
- slower mental processes
- decreased ability to problem solve
- reduced ability to make decisions quickly
- cognitive distortions
what are sleep disorders
disturbances to typical sleeping and waking patterns
circadian sleep disorders
sleep disorders that interfere with the typical regulation of the circadian rhythm of sleep, leading to a change in the sleep-wake cycle
DSPS
ASPD
what causes circadian rhythm sleep disorders
disruptions to the typical sleep-wake cycle.
this could be biological issues or lifestyle changes (shift work)
effects of circadian rhythm sleep disorders
- amplified emotional responses
- fatigue
- irritability
- reduced ability to concentrate
can be disruptive to an individuals lifestyle - sleeping and waking at abnormal times can result in an individual being late for commitments or feeling tired at abnormal times
Delayed Sleep Phase Syndrome (DSPS)
a type of circadian rhythm sleep disorder in which sleep and waking occur later than usual. The sleep wake cycle is delayed
e.g. instead of sleeping 10pm-8am, an individual with DSPS may sleep 1am-11pm.
what causes DSPS
Delayed Sleep Phase Syndrome is caused by a misalignment between external and internal cues that regulate the circadian rhythm,
external cues (light and dark) are received at an appropriate time, while internal cues (melatonin secretion) are delayed.
Advanced Sleep Phase Syndrome (ASPD)
a type of circadian rhythm sleep disorder in which sleep and waking occur earlier than usual. The sleep wake cycle is advanced.
e.g. instead of sleeping 10am-8pm, an individual with ASPD may sleep 7pm-5am.
what causes ASPD
Advanced Sleep Phase Disorder is caused by a misalignment between external and internal cues that regulate the circadian rhythm.
external cues (light and dark) are received at an appropriate time, while internal cues (melatonin secretion) occur earlier.
compare DSPS and ASPD
Both are caused by a misalignment between external and internal cues that regulate the circadian rhythm.
DSPS - internal cues are delayed
ASPD - internal cues are advanced
shift work
an occupation that involves working at unusual hours, such as working overnight.
this can mean an individual has to sleep at unusual times, such as during the day.
shift work also includes rotating shift work - working a week of morning shifts, and a week of night shifts.
How does shift work affect sleep?
shift worker’s circadian rhythm is constantly changing. This leads to individuals having difficulty initiating sleep and waking while adjusting from one shift to another.
effects of shift work on sleep
- insomnia
- fragmented sleep
- circadian rhythm phase disorders (DSPS, ASPD)
- quality and quantity of sleep can be affected
difference between DSPS/ASPD and shift work
DSPS/ASPD are caused by problems with internal cues, while shift work is caused by problems with external cues.
bright light therapy
a method used to adjust a person’s circadian rhythm through exposure to a high-intensity light source
over time, bright light therapy works to readjust the circadian rhythm so that an individuals sleep and wake times are more appropriate
How does bright light therapy work?
- an individual is exposed to a bright light source
- the SCN receives this as an external cue, which acts as a biological mechanism to regulate the sleep-wake cycle
- this readjusts the circadian rhythm and ensures that sleeping and waking occur at the desired time
how long do bright light therapy sessions last
15 minutes to a couple of hours, and are conducted up to a few times a day for at least a few consecutive days
factors essential to bright light therapy
- appropriate timing of exposure sessions (must occur at the right time to feel awake at the right time)
- the right amount of light (intensity of light and length of sessions must be appropriate to the persons disorder)
- safe exposure (individual doesn’t look directly into light and face is adequate distance from light source)
how does bright light therapy work for DSPS
individual is exposed to light source in the morning at appropriate waking time. this acts as an external cue to the SCN and promotes wakefulness. This helps the SCN send signals for melatonin release earlier.
how does bright light therapy work for ASPD
individual is exposed to light source in the evening when feeling sleepy. this acts as an external cue to the SCN and promotes wakefulness. This helps the SCN send signals for melatonin release later, and cortisol release later in the morning.
how does bright light therapy work for shift workers
depends on timing and details of individuals work. An individual is best exposed to the bright light source before beginning their shift.
what is sleep hygiene
the practices and habits that promote an individuals sleep patterns
sleep hygiene involves:
timing - sleeping/waking at a time that enables an adequate amount of sleep
sound - sleeping in a quiet space
light - sleeping in a dark space
comfort - sleeping in a comfortable space
technology/devices - avoiding bright screens close to bedtime
association with bed - avoiding doing activities other than sleeping in bed (e.g. studying)
food/drink consumption - avoiding large meals, caffeine, and alcohol before sleeping time
exercise - engaging in exercise early in the day and avoiding exercise close to sleeping time
what does sleep hygiene do
improves sleep-wake patterns by making it easier to fall asleep at an appropriate time and increasing the likelihood of experiencing quality sleep.
how does sleep hygiene influence mental wellbeing
sleep hygiene enables individuals to experience good quality sleep of an adequate quantity, and sleep is important for mental well-being.
the relationship between sleep and mental well-being is bidirectional, meaning that sleep can impact mental wellbeing, and mental wellbeing can impact sleep
zeitgebers
external cues from the environment that influence the circadian rhythm
includes light, temperature, eating and drinking patterns, exercise
daylight
daylight - a type of light an individual is exposed to during the day and is mostly natural blue light
blue light
blue light - a type of light that can be emitted both naturally (daylight) and artificially (technology)
daylight and blue light as zeitgebers
both lights act as external cues that signal to the SCN to cease melatonin production and promote wakefullness
how is temperature a zeitgeber
the degree of external heat in the environment that can influence the quality and quantity of sleep.
research suggests there is a link between having a cool room and experiencing improved quality/quantity of sleep
what are eating and drinking patterns
what,when, and how much food and drink is consumed by an individual
what does eating too close to sleeping time do
stimulates digestive system and makes it harder to fall asleep
what types of food/drink influence sleep
caffeine
alcohol
high sugar/high fat
spicy foods
How does caffeine affect sleep?
increases nervous system activity and promotes wakefulness
how does alcohol affect sleep
increases feelings of tiredness, making it easier to fall asleep, but impairs quality
how do high sugar/high fat foods affect sleep
studies suggest consuming a high sugar/high fat diet negatively impacts quality and quantity of sleep
how do spicy foods affect sleep
increases body temperature which can impair sleep
stimulates and increases metabolic processes
how does the amount of food we eat affect sleep
going to sleep hungry or overfull can lead to poorer sleep quality and quantity
how to improve sleep hygiene
- Establish regular sleep onset and wake schedules.
- Minimise exposure to light before bed and maximise exposure to light in the morning.
- Associate the bed and bedroom with sleep.
- Avoid stimulating activities before bed such as exercise.
- Avoid napping.
- Improve sleep environment.
- Bedtime routine.
Sleep Hygiene
The practices and habits that promote an individual’s sleep patterns.
How do we fall asleep?
Information from our environmental cues dictates the messages the SCN sends to the pineal gland, which is responsible for the production and release of melatonin.
Amplitude
Intensity + height of brain waves.
Ultradian Rhythm
Biological and behavioural changes that occur in a cycle and lasts less than 24-hours.
Frequency
No. of brain waves that occur per second.
Ultradian Rhythm
Biological and behavioural changes that occur in a cycle and lasts less than 24-hours.
