Unit 4 AOS 1 Flashcards
Sleep
define sleep
Sleep is a regular and naturally occurring altered state of consciousness that involves a loss of awareness and disengagement with internal and external stimuli.
what can sleep be considered as?
Sleep can also be considered a psychological construct.
what is sleep governed by?
We sleep every day, governed by our circadian rhythm (biological clock)
define naturally occurring
occurs without the need of aids
define altered state of consciousness
a state where we have lowered awareness/alertness and involves distortions
define psychological construct
A psychological construct refers to psychological phenomena that we believe exist but cannot see or touch. It’s also a construct that can be difficult to overtly measure.
what awareness do you have when your asleep?
When you are asleep you are often have very little awareness of your surroundings, you have lowered self control and perception
what consciousness can sleep be described as?
Sleep can be described as a regular and naturally occurring altered state of consciousness.
define consciousness
Consciousness is the level of awareness an individual has over their thoughts, feelings, perceptions and existence.
what range is consciousness on?
Consciousness ranges along a continuum
what are the boundaries of consciousness?
- Consciousness is not an “all or nothing” experience, there are variations in the extent or degree of awareness we experience at different times
- There are no distinct boundaries between one state and another
what are the states of consciousness?
- altered state of consciousness
- normal waking consciousness
examples of altered state of consciousness?
- coma
- sleep
- anaesthetised
- alcohol-induced
- meditation
- drowsy
- day dreaming
examples of normal waking consciousness?
- relaxed state
- focussed attention
define normal waking consciousness
Refers to the states of consciousness associated with being awake and aware of our thoughts, memories, feelings and the sensations we are experiencing from the outside world
features of normal waking consciousness?
- Our perceptions and thoughts continue to be organized and clear, we perceive the world as real and maintain a sense of time and place
- Its not one single state- but rather includes all states of consciousness that involve
heightened awareness
how long are we in normal waking consciousness?
2/3 of our day is spent in NWC
define altered state of consciousness
Any state of consciousness that is distinctly different from normal waking consciousness, characterised by lowered levels of awareness
what are the sub categories of altered state of consciousness?
- naturally occurring altered state of consciousness
- induced altered state of consciousness
define naturally occurring altered state of consciousness
a type of altered state of consciousness that occurs without intervention
examples of naturally occurring altered state of consciousness?
- sleep
- day dreaming
define induced altered state of consciousness
a types of altered state of consciousness that occurs due to purposeful action or aid
examples of induced occurring altered state of consciousness?
- meditation
- hypnosis
- influence of alcohol and/or drugs
what are the characteristics of sleep?
- A reduced ability to control behaviour
- Reduction in the control we have over thoughts, (e.g. dreams)
- Lowered perception to pain
- Less accurate understanding of the passage of time
what is sleep made up of?
Sleep is made up of both NREM and REM stages
what is Rapid eye movement (REM)?
- Characterised by rapid eye movement, high levels of brain activity and low levels of physical activity
- Low levels of somatic nervous system activity – “paradoxical sleep”
what is Non-rapid eye movement (NREM)?
- Characterised by lack of rapid eye movement
- Is subdivided into three different stages
what is a sleep episode?
the full duration of time spent asleep
what is a sleep episode made up of?
Made up of multiple repeated sleep cycles of REM and NREM – sleep cycles which last approximately 90 minutes
what is a sleep cycle?
A sleep cycle is 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 the purpose of sleep?
- survival
- physical recovery
- mental recovery
characteristics of REM sleep?
- During REM sleep, the sleeper is virtually paralysed; most muscle movement is not possible (muscle paralysis)
- Involves sudden onsets of rapid eye-movement beneath closed eyelids
- Dreaming tends to occur during REM
- The sleeper frequently recalls dreams when woken during REM sleep
- REM is a light stage of sleep; Sleepers can be woken fairly easily from this stage
- During REM, the brain is highly active and is it thought this stage replenishes the brain
what happens to the amount of REM sleep in a sleep episode?
The amount of time spent in REM increases as the sleep episode progresses, with the largest amount of REM sleep occurring immediately before waking (can last up to an hour in the last cycle)
how much of a sleep episode is REM?
REM sleep makes up approx 20-25% of a sleep episode for most age groups
what is NREM divided into?
NREM sleep is subdivided into 3 different stages (NREM1, NREM 2, NREM 3)
what does REM stand for?
RAPID EYE MOVEMENT
what does NREM stand for?
NON RAPID EYE MOVEMENT
characteristics of NREM sleep?
- Muscle movement is possible for the sleeper during NREM sleep
- The sleeper does not frequently recall dreams when woken during NREM
- NREM is believed to be important for replenishing the body
what happens to the amount of NREM sleep in a sleep episode?
The amount of time spent in NREM sleep is highest during the first half of a sleep episode
how much of a sleep episode is NREM?
NREM sleep makes up approximately 75-80% of a sleep episode
what type of sleep is NREM1 and NREM2?
NREM1 and NREM2 are light sleep and the sleeper may not realise that they have been sleeping if woken during these stages
what type of sleep is NREM3?
NREM3 is deep sleep and the sleeper is likely to feel drowsy and disoriented if woken during these stages
Differences (REM vs. NREM)?
- REM duration becomes longer over the later sleep cycles, whereas NREM becomes shorter.
- NREM stages 3 are generally evident in first couple of cycles, whereas REM occurs throughout the night.
- Overall time spent in NREM is greater than REM.
- NREM sleep has 3 stages and REM has one
define hypnogram?
sleep graph that tracks the proportion of time spent in each stage of sleep
what are the lightest and deepest sleep stages in NREM?
Each successive stage of NREM sleep is indicative of a deeper sleep, with stage 1 being the lightest and stage 3 as the deepest
characteristics of Stage 1 NREM?
- During the transition from being awake to being asleep, we enter a relaxed state known as a hypnogogic state.
- We may experience hallucinatory images, such as flashes of light and Hypnic jerks (involuntary muscle twitches that cause us to jolt)
- Stage 1 is brief, lasting 5-10 minutes. It’s very light and we are easily awakened. People woken during Stage 1 will often report that they weren’t actually asleep.
- Overall, slowdown in brain wave patterns (alpha, then replaced by theta waves)
characteristics of Stage 2 NREM?
- Generally considered the point at which true sleep starts. Stage 2 lasts about 10-25 minutes in our first sleep cycle (lengthens with each successive cycle), and we are still easy woken.
- As we slip deeper into Stage 2, we become more relaxed – breathing, heart rate and blood pressure decrease and we are unlikely to respond to anything except strong/loud stimuli
- Predominantly theta waves
characteristics of Stage 3 NREM?
- Deepest stage of sleep (also known as slow wave sleep)
- We become less responsive to external stimuli
- Our muscles are completely relaxed and we barely move. Delta waves dominate.
- More difficult to awaken - if awoken, we feel very groggy and disorientated.
- Our eyes do not move and we become even more relaxed.
- Often the stage where sleep walking and sleep talking occur
- Decreases in length as cycles progress through the night. In the latter half of a sleep episode, there may no stage 3 sleep at all.
eyes in REM vs NREM?
REM - fast, jerky
NREM - slow, minimal
brainwaves in REM vs NREM?
REM - beta
NREM - delta
body in REM vs NREM?
REM - Paralysis
NREM - Movement possible
Physiological Responses in REM vs NREM?
REM - increases
NREM - decreases
Presences of Dreams in REM vs NREM?
REM - yes
NREM - no
Timing in Night in REM vs NREM?
REM - Increases across the night 2min - 1 hour
NREM - Start of the sleep cycle
% of Sleep in REM vs NREM?
REM - ~20%
NREM - ~80%
Necessary for, REM vs NREM?
REM - mind
NREM - body
what are the ways we can measure sleep?
- EEG
- EOG
- EMG
- SLEEP DIARIES
- VIDEO MONITORING
Measurement of physiological responses in sleep?
- EEG
- EOG
- EMG
what do these ways of measuring physiological responses enable and provide?
- Enable researchers to obtain data on bodily changes during different SOC.
- Provide valuable info on levels of awareness that occur in different states
what do the three common physiological measures in sleep include changes in?
brain wave patterns, muscle activity & eye movements
define Electroencephalograph (EEG)
An EEG, is a device that Detects, Amplifies and Records Electrical activity of the brain (in the form of brainwaves).
how is an EEG achieved?
Achieved by placing electrodes on the scalp, which detect signals from neurons in the brain
how is an EEG shown?
The brain waves recorded are displayed as a graph on a computer
how can an EEG measure sleep?
Different states of consciousness cause changes in brain-wave patterns
define brain waves
a pattern of electrical activity in the brain caused by neurons communicating
what do brain waves provide?
Provide an indication of a person’s level of alertness (ie. state of consciousness)
how are brain waves read and represented?
- They are visually represented as wavy lines
- When reading an EEG recording, both the frequency and amplitude are recorded
what is frequency with regards to brain waves?
Frequency (rate) - how many brainwaves there are per second. Ie. How close the waves are to one another. The closer = the higher frequency
what is amplitude with regards to brain waves?
Amplitude (height) - the intensity of the electric current in the brain. The height of peaks and dips in the waves. The higher the peak = the higher the amplitude.
what do high frequency and low amplitude waves equal?
high levels of alertness
what do low frequency and high amplitude waves equal?
lower levels of alertness
what is an EEG likely to show in REM sleep?
higher frequency and lower amplitude brain waves in REM sleep - beta like brain waves
what is an EEG likely to show in NREM sleep stage 1 sleep?
high frequency and low amplitude in NREM sleep stage 1 (transitioning from wakefulness to sleep), but lower frequency and higher amplitude than normal-waking consciousness - alpha like brain waves
what is an EEG likely to show in NREM sleep stage 2 sleep?
medium frequency and medium amplitude in NREM sleep stage 2 (light sleep) - theta like brain waves
what is an EEG likely to show in NREM sleep stage 3 sleep?
lower frequency and higher amplitude in NREM sleep stage 3 (deep sleep) - delta like brain waves
what is a strength of EEG’s?
useful for sleep studies or diagnoses of patients with brain damage or a neurological or mental disorder.
what is a limitation of EEG’s?
Limitation of EEGs as a measure of sleep is that it measures neural activity underneath a thick and hard skull and thus is not entirely precise. It also does not pinpoint or identify functional or dysfunctional areas of the brain as well as neuroimaging techniques, such as an fMRI
what are the types of brain waves in sleep?
- Beta
- Alpha
- Theta
- Delta
what can an EEG show that demonstrates a sleeper is truly asleep?
During NREM sleep stage 2, the sleeper is considered ‘truly asleep’. EEG readings can reflect this by showing ‘sleep spindles’, which are brief bursts of high frequency waves which sleep researchers identify as the point where a sleeper is truly asleep.
what are beta waves frequency and amplitude?
- high frequency
- low amplitude
what are alpha waves frequency and amplitude?
- high frequency (but lower than beta)
- low amplitude (but higher than beta)
what are theta waves frequency and amplitude?
- medium frequency
- medium-high amplitude
what are delta waves frequency and amplitude?
- low frequency
- high amplitude
define electromyograph (EMG)
The EMG Detects, Amplifies and Records Electrical of the body’s muscles.
what does an EMG record?
EMG recordings indicate changes in muscle activity (movement) and muscle tone (tension).
how is an EMG obtained?
- Obtained by attaching electrodes to the skin above muscles.
- Sometimes the activity in facial muscles is recorded, leg muscles, muscles on the torso or a combination of these
How does an EMG indicate changes in SOC?
- E.g. when falling asleep, our muscles progressively relax (decrease in muscle tone)
- Generally, EMG measures indicate that the higher level of muscular activity and tone, the more alert we tend to be
define Electro-oculargraph (EOG)
The EOG Detects, Amplifies and Records Electrical of the muscles surrounding the eyes.
what does an EOG indicate?
Little to no activity of these muscles would indicate low levels of awareness
what is an EOG most commonly used for?
Most commonly used to measure changes in eye movements associated with different stages of sleep and dreaming
why is an EOG valuable?
Extremely valuable in differentiating between two different stages of sleep Rapid Eye Movement (REM) sleep and non-rapid eye-movement (NREM).
what is DARE?
detects, amplifies and records the electrical activity of…
what does an ECG do?
The ECG detects, amplifies and records the electrical activity of the heart (Electrocardiogram)
what are the subjective reporting of consciousness?
- Sleep diaries
- Video Monitoring
what does subjective reporting involve?
Subjective reporting involves the use of self-reports — the participant’s written or spoken responses to questions, or statements by the researcher. (qualitative data)
what are sleep diaries?
Sleep diaries are the most widely used method - they are a record of individual descriptions of amount, nature and quality of sleep
what are sleep diaries used in conduction with?
Often used in conjunction with physiological measures such as EEG and EMG
what can sleep diary monitor?
Can self-monitor times fallen asleep, number of wake-ups, how well rested one feels, events that affect sleep (naps, caffeine consumption, exercise etc.)
how are self reports subjective?
Self-reports are considered to be subjective because the data collected from a participant is based on their personal opinion, interpretation, point of view or judgment.
in sleep diaries what can records be kept of?
- the time when trying to fall asleep
- the time when it is believed sleep onset occurred
- the number, the time and length of awakenings during sleep
- the time of waking up in the morning
- the time of getting up after waking up in the morning
- how well rested the individual feels upon awakening
- how sleepy the individual feels at different times during the day
what is video monitoring?
Provides behavioural data of sleep using camera and audio technologies to record an individual as they sleep
what is video monitoring commonly used for?
Video monitoring is most commonly used in the study of sleep disturbances/disorders.
characteristics of video monitoring?
- May also be conducted in a home environment, but usually in a sleep lab
- Can be used in conjunction with physiological measures to provide more validity
*Important for patients who have a serious sleep disorder
Responses in video monitoring that may be observed include…?
- changes in posture/body position
- amount of ‘tossing and turning’
- sleep-related breathing problems
- what happens when awakening from a nightmare or night terror
- behaviours associated with sleepwalking.
what type of measure is EEGs, EMGs, and EOGs?
EEGs, EMGs, and EOGs are considered to be objective physiological measures.
what do objective physiological measures such as EEGs, EMGs and EOGs provide?
They provide reliable, unbiased, quantitative data that can indicate someone’s state of consciousness (they do not provide qualitative detail about the personal experience of sleep, such as an individual’s thoughts or feelings).
are EEGs, EMGs and EOGs aways accurate?
Changes in physiological responses may be due to factors other than a change in consciousness, thus the findings may lack validity at times.
what type of measuring are sleep diaries and video monitoring?
sleep diaries and video monitoring are considered to be subjective measures
what are subjective measures?
This means that information is provided by an individual and is related to their personal experiences. The accuracy and reliability of such measures can be limited due to their subjective nature. It is important to note that subjective measures can provide both qualitative and quantitative data.
how can subjective measures provide both qualitative and quantitative data?
For example, a sleep diary can provide qualitative information about sleep, such as how an individual feels before going to sleep, but also quantitative information, such as how long an individual slept for.
what are some limitations of sleep measures?
Some techniques can be disruptive, invasive, or may require an individual to sleep in a sleep laboratory for a period of time. Changes to an individual’s regular sleep patterns, such as having to record their sleep or having electrodes attached to their head whilst asleep, can influence the quality and quantity of an individual’s sleep.
Therefore, sleep measures may not provide a true reflection of an individual’s usual sleeping patterns.
EEG in Measuring REM vs. NREM Sleep
REM - Beta (like) waves
NREM - Theta - Delta waves
EOG in Measuring REM vs. NREM Sleep
REM - High Activity
NREM - Slow, rolling
EMG in Measuring REM vs. NREM Sleep
REM - No movement/Paralysis
NREM - Some movement
what are the types of rhythms?
- Biological rhythms
- Circadian rhythms
- Ultradian rhythms
define Biological rhythms
repeated biological processes that are regulated by internal mechanisms
define Circadian rhythms
biological process that follow a 24-hour cycle
define Ultradian rhythms
biological processes that occur more than once in 24 hours
what is the circadian rhythm?
- Sleep-wake cycle
Note: you cannot just say “sleep”
what is the ultradian rhythm?
sleep cycles made up of REM and NREM within the sleep-wake cycle
what is involved in the regulation of sleep-wake patterns?
The suprachiasmatic nucleus and melatonin
what is the suprachiasmatic nucleus (SCN)?
An area of the hypothalamus responsible for regulating sleep- wake patterns
what does the suprachiasmatic nucleus (SCN) act as?
Acts like an internal body clock
where is the suprachiasmatic nucleus (SCN) located?
Located above the optic chiasm (intersection of the optic nerve fibres between each eye)
what does the suprachiasmatic nucleus (SCN) receive?
Receives information from both external and internal cues to help modulate the circadian rhythm
what is the suprachiasmatic nucleus (SCN) influenced by?
Influenced by zeitgebers, environmental cues such as light, temperature, eating patterns, exercise and social activity which help to regulate the circadian rhythm
what does the suprachiasmatic nucleus (SCN) sent messages to?
Sends messages to the pineal gland which produces and secretes melatonin
what is melatonin?
- a sleep-inducing/ promoting hormone
- A hormone associated with alertness
what are levels of melatonin controlled by?
Levels of melatonin in the blood stream are controlled by the SCN as it adjusts our sleep-wake cycle, directing the pineal gland to secrete more or less melatonin
what is the main influence that the suprachiasmatic nucleus (SCN) detects?
levels of light in the environment
what do low levels of melatonin mean?
- Low levels = more alert (less melatonin)
- Sunrise/ morning – high levels of light in the environment
what do high levels of melatonin mean?
- Higher levels = more drowsy (more melatonin)
- Sunset/ dusk – low levels of light in the environment
what are the steps of how the SCN and melatonin regulate the sleep-wake cycle at night?
- The SCN receives external and internal cues
- After receiving cues, the SCN sends neural messages (signals) 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
what does melatonin release/suppression cause?
sleepiness/wakefulness
what sleep patterns change with age?
- Sleep onset
- Sleep duration
- Awakening during sleep
- Proportion of REM sleep
- Proportion of NREM sleep
Changes in the Circadian Rhythm in newborns?
Newborns do not have an established circadian rhythm. Their sleeping patterns are erratic, with their sleep distributed across the full 24-hour day.
Changes in the Circadian Rhythm in infants?
From about 4 months, an infant’s sleep becomes more nocturnal. As they continue to develop and experience rapid physiological changes, children begin to have a fairly consistent circadian rhythm.
Changes in the Circadian Rhythm in adolescents?
Adolescents experience a shift in their circadian rhythm; they may not feel tired until later in the evening. This can result in a delayed sleep phase syndrome.
Changes in the Circadian Rhythm in adults?
After adolescence, the circadian rhythm returns to more normal timing, and most healthy adults experience a consistent circadian rhythm if they are following a regular routine with relatively stable bedtimes and wake times.
Changes in the Circadian Rhythm in older adults?
Older adults may prefer an earlier bedtime and therefore an earlier waking in the morning.
As a person ages throughout the lifespan, their need for, and experience of sleep changes in the following ways…?
- The total amount of sleep decreases
- The proportion of REM sleep decreases significantly from birth to 2 years old
- The amount of NREM Stage 3 decreases (replaced mostly by NREM 2)
- A circadian phase delay occurs during adolescence
- Awakenings throughout the night increase from adulthood to old age
- Sleep efficiency (the % of time in bed is spent asleep) reduces
total sleep for newborns?
14-17 hours
total sleep for infants?
13.5 hours on average (approx 12-15hrs range)
total sleep for childhood?
11 hours
total sleep for adolescent?
9 hours
total sleep for young adulthood?
8 hours
total sleep for adulthood?
7 – 8 hours
total sleep for old age?
6 hours
how old is a newborn?
(0-3 months)
how old is an infant?
(4 months – 2 years)
how old is childhood?
(2 – 14 years)
how old is a adolescent?
(14 – 18 years)
how old is a young adulthood?
(18 – 30 years)
how old is a adulthood?
(30 – 75 years)
how old is a old age?
(75+ years)
what is the proportion of REM and NREM for newborns?
REM - 50%
NREM - 50%
what is the proportion of REM and NREM for infants?
REM - 50%
NREM - 50%
what is the proportion of REM and NREM for early childhood?
REM - 35%
NREM - 65%
what is the proportion of REM and NREM for adolescent?
REM - 20%
NREM - 80%
what is the proportion of REM and NREM for young adulthood?
REM - 20%
NREM - 80%
what is the proportion of REM and NREM for adulthood?
REM - 20%
NREM - 80%
what is the proportion of REM and NREM for old age?
REM - 20%
NREM - 80%
characteristics of newborn sleep?
- No established circadian rhythm
- Erratic sleep across the entire 24 hours
- Requires most sleep for rapid growth
- Require a lot of REM for brain development
characteristics of infant sleep?
- Sleep becomes more nocturnal
- A more consistent circadian rhythm
characteristics of childhood sleep?
- A lot of variation in this stage of life
- As children drop their daytime nap, sleep shifts to earlier in the evening
- From the age of 6 years, circadian rhythm begins to delay, and sleep is shifted later
characteristics of adolescent sleep?
- Sleep-wake cycle shift in adolescence, caused by a shift in the release in melatonin by 1-2 hours, delaying sleep onset by up to 2 hours
- Due to school and other commitments, they go to sleep later and wake up earlier resulting in sleep deprivation
characteristics of young adulthood sleep?
- Consistent circadian rhythm
- At the end of this stage, advance sleep shift occurs (an earlier sleep onset)
- Melatonin concentration decreases
characteristics of adulthood sleep?
- Can vary depending on lifestyle
- Melatonin continues to decline
- In later years of this stage, NREM 2 starts to replace NREM 3
- Lifestyle factors play a huge role - work life balance, parenting, changing of family dynamics
characteristics of old age sleep?
- Advanced circadian rhythm disorder can occur (early sleep onset and early wake time)
- Many more wakening during a sleep episode due to less NREM 3 and more NREM 2
- Less sleep may be due to a lack of ability to sleep, rather than a change in need to sleep.
- Medications, reduced social and physical activity, bereavment, change of living arrangements
define Sleep deprivation
the general term used to describe a state caused by inadequate quantity or quality of sleep
what is involved in sleep deprivation?
- Being denied of necessary or desired amount of sleep
- Can lead to a variety of psychological and physiological effects:
- Affective
- Behavioural
- Cognitive
what are the types of sleep deprivation?
- Partial sleep deprivation
- Total sleep deprivation
define Partial sleep deprivation
Involves having less sleep (either quality or quantity) than what is normally required
- Some sleep in a 24 hour period but not enough
define Total sleep deprivation
Involves not having any sleep at all (in a 24 hr period) over a short-term or long-term period
what are the types of effects that sleep deprivation can have?
- Affective
- Behavioural
- Cognitive
what are affective effects?
the changes in emotions and emotional responses that arise from sleep deprivation
what does sleep deprivation interfere with affectively?
Sleep deprivation interferes with emotional regulation and reactivity
- Often results in an amplified emotional response – emotional response may be too quick, more intense, out of proportion, exaggerated
examples of affective effects of sleep deprivation?
- Poor emotional regulation – amplified emotional response
- Mood changes
- Increased negative emotions
- Difficulty judging others’ emotions
- Reduced empathy
- Heightened anxiety/ depression
- Irritability and moodiness
- Lack of motivation
what are behavioural effects?
the changes in actions and the ability to control them that arise from sleep deprivation
examples of behavioural effects of sleep deprivation?
- Excessive sleepiness during the day
- Increased likelihood of engaging in risk taking behaviours
- Reduced reaction times
- Reduced efficiency, taking longer to complete tasks
- Reduced motor control and clumsiness
- Microsleeps (sleep episodes that last for 15 seconds or less where you lose conscious control of actions)
what are cognitive effects?
the changes in mental processes that arise from sleep deprivation
examples of cognitive effects of sleep deprivation?
- Impaired memory (trouble encoding, not retrieving)
- Illogical/ irrational thoughts
- Poor decision making
- Reduced ability to perform cognitive tasks
- Impaired problem solving
- Impaired visual and spatial ability
- Trouble with simple monotonous tasks (complex tasks requiring high mental effort often can still be completed)
define BAC
BAC: blood alcohol concentration, a measure of how much alcohol is in a person’s blood stream
what is a BAC of 0.05 mean?
If a person’s BAC is 0.05 this means, there are 0.05 grams of alcohol for every 100 millilitres of blood
what type of drug is alcohol and what does it do?
Alcohol is a depressant and therefore slows down the nervous system which reduces:
- Alertness
- Concentration
- Reflexes
- Decision making
what does a high BAC do?
The higher a person’s BAC, the more their cognition and affect (emotions) are likely to be impaired
what are the affective effects of alcohol compared to sleep deprivation?
- Generally, sleep deprivation negatively affects emotional functioning making them more irritable or sensitive
- Alcohol can have a range of effects, usually resulting in more extreme (amplified) emotions:
- Happy and excited
- Angry
- Sad
what are the cognitive effects of alcohol compared to sleep deprivation?
Impairments include:
- Slower mental processes
- Decreased ability to reason and problem solve
- Reduced ability to make decisions quickly and effectively
- Cognitive distortions
what are the equivalence of BAC and sleep deprivation?
- A BAC of 0.05 is equivalent in terms of impaired cognition to 17 hours sleeplessness
- A BAC of 0.10 is equivalent in terms of impaired cognition to 24 hours sleeplessness
what is the legal BAC limit on the road?
0.05 for a fully licenced driver
0.00 for L and P platers
define Circadian Rhythm Phase Disorders
Sleep disorders that interfere with the typical regulation of the circadian rhythm of sleep, leading to a change in the sleep-wake cycle
what are Circadian Rhythm Phase Disorders caused by?
Can be caused by internal factors (medical conditions, age-related changes, natural shifts etc) or external factors (environment, work, jetlag etc)
what are the Circadian Rhythm Phase Disorders?
- Delayed Sleep Phase Syndrome (DSPS)
- Advanced sleep Phase Disorder (ASPD)
- Shift Work
→ all of these can severely impact quality of life
what is a cause of Circadian Rhythm Phase Disorders?
- Shift work
define Delayed Sleep Phase Syndrome (DSPS)
A circadian rhythm phase disorder in which sleep and waking occur later than usual
what does DSPS lead to?
→ Leads to excessive daytime sleepiness and difficulties associated with sleep deprivation
→ Especially a problem if this routine in in conflict with work or school schedules, resulting in insufficient sleep quality and quantity
what is DSPS caused by?
- Caused by a misalignment between external and internal cues that regulate the circadian rhythm
- External cues are received at an appropriate time, but internal cues are not – light in the morning and dark the evening are experienced, but the individual does not receive internal cues which causes melatonin secretion to be delayed
what is a sub category of DSPS?
Sleep-wake shifts in adolescence
why does adolescents sleep-wake cycle shift?
→ Occurs due to puberty, where there is a hormonally-induced shift of the body clock forward by 1-2 hours
→ this occurs because melatonin is released 1-2 hours later than adults, often not feeling sleepy until approx 11pm, resulting in sleep debt (amount of sleep loss accumulated overtime)
→ due to school commitments (getting up early) and other demands (homework, social commitments, sport, part-time work and screen time etc), this can excarcebate sleep dept
why does DSPS occur?
No known cause as to why this occurs (with the exception of adolescent sleep wake cycle shift)
define Advanced Sleep Phase Disorder (ASPD)
A circadian rhythm phase disorder in which sleep and waking occur earlier than usual
what does ASPD caused by?
- Caused by a misalignment between external and internal cues that regulate the circadian rhythm
- External cues are received at an appropriate time, but internal cues are not
- light in the morning and dark in the evening are experienced, but the individual does not receive internal cues properly in the morning and night, leading to sleep and waking earlier as melatonin is secreted earlier
who does ASPD occur mostly in?
Occurs more commonly in the elderly age group
is ASPD an issue?
Generally not an issue if these sleep times suit the individual’s lifestyle, although can have impacts on social engagements, work and family life. It can also feel isolating.
what is shift work?
An occupation that involves working at unusual hours, such as working overnight, early morning shifts or rotating shifts
what does shift work cause?
Constantly changing rhythms, forcing people to be awake when they should be sleeping,as humans are not nocturnal
what happens to biological cues with shift work?
Biological cues are often lost, causing difficulties falling asleep, particularly during the day
how does shift work effect individuals?
Individuals often have difficulty initiating sleep and waking while adjusting from one shift to another
what do the effects of shift work lead to?
Effects of shift work often leads to daytime sleepiness, partial sleep deprivation, lack of REM and NREM sleep - which are both important for revitalising mental processes and body repairs & immune function
what are shift workers at a greater risk to?
Shift workers are at greater risk of mood disorders, gastrointestinal disorders, diabetes, chronic fatigue, cardiovascular disease, accidents (including on the job), relationship breakdown and more.
define Bright Light Therapy
A method used to adjust a person’s circadian rhythm through exposure to a high-intensity light source, also known as phototherapy
what happens in bright light therapy?
The eyes are exposed to intense but safe amounts of light for a specific and regular length of time, as artificial light can be used to influence the SCN to inhibit the release of melatonin
what does bright light therapy do overtime?
Over time, bright light therapy works to readjust the circadian rhythm, so that an individual’s sleep and wake times are more appropriate
what are the steps in bright light therapy?
- An individual is exposed to 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.
factors in bright light therapy?
- Appropriate timing of exposure sessions
- The right amount of light
- Safe exposure
what is the an appropriate timing of exposure sessions in bright light therapy?
Bright light therapy must occur at the right time in order to make a person feel awake at the right time. For example, people who feel sleepy earlier than appropriate, such as by 5pm, can conduct an ex posure session in the late afternoon or early evening in order to help them stay awake and fall asleep later at a more appropriate time.
what is the right amount of light in bright light therapy?
The intensity of the light and the length of exposure sessions must be appropriate to the person’s disorder and desired changes to their circadian rhythm. The intensity and length should also be built up gradually in order to avoid negative side effects like headaches.
what is safe exposure in bright light therapy?
A person should not look directly at the light, and their face should be an adequate distance away from the light source.
what is a treatment for circadian rhythm sleep disorders?
bright light therapy
define sleep hygiene
The practices and habits that promote an individual’s sleep patterns
what does sleep hygiene improve?
Improves the quality and quantity of sleep
what does sleep hygiene involve?
- Time; sleeping and waking at a time that enables an adequate amount of sleep, and sleeping and waking at a consistent time each day
- Sound; sleeping in a quiet space
- Light; sleeping in a dark space and reducing exposure to bright light
- Comfort; sleeping in a comfortable place
- Technology; avoiding screens prior to sleep
- Association with bed; avoiding other activities like studying or watching tv
- Food and drink consumption; avoiding large meals, caffeine and alcohol before sleep
- Exercise, avoiding exercise prior to sleep
what can good sleep hygiene influence?
Good sleep hygiene can also positively influence mental wellbeing
define Zeitgebers
external cues from the environment that influence circadian rhythm
what are the main zeitgebers?
- light
- temperature
- eating and drinking patterns
what are the types of light zeitgebers?
Daylight and Blue light
how does light act as a zeitgeber?
Light acts as an external cue by signalling the SCN to promote wakefulness
how is daylight a zeitgeber?
- Predominantly natural blue light, regulates the sleep-wake cycle by signalling the SCN to cease melatonin
- Therefore, promotes wakefulness
how is artificial blue light a zeitgeber?
- In a similar way to natural light, blue like signals the SCN to cease melatonin production
- Produced by technological devices (phone, laptop, tv etc.)
what in temperature influences sleep?
The degree of external heat in the environment that can influence the quality and quantity of sleep
what temperature is good for sleep?
- Research suggests a cool room temperature is related to improved quantity and quality of sleep
→Believed to help the body maintain temperature
→18.3 degrees celsius is suggested to be the ideal room temp - Additionally, extreme temperatures (high or low) are not considered good for sleep
define eating and drinking patterns
What, when and how much food and drink is consumed by an individual
how does when we eat and drink impact sleep?
Eating too close to sleep time can make it difficult to sleep due to stimulation of the digestive system
how does how much we eat and drink impact sleep?
Going to sleep either too hungry or too full can lead to poorer sleep quality and quantity
how does what we eat and drink impact sleep?
- Some foods can positively impact sleep
- Other foods can negatively impact sleep
what food and drink impact sleep?
- Caffeine
- Alcohol
- High-sugar & high-fat foods
- Spicy foods
how does caffeine impact sleep?
- A stimulant –increases the activity of the nervous system and promotes wakefulness
- Blocks sleep-promoting hormones and neurotransmitters.
how does alcohol impact sleep?
- A depressant – increases tiredness and makes it easier to fall asleep.
- Negatively impacts sleep in the second half of the night.
how does high-sugar & high-fat foods impact sleep?
A diet high in sugar and fat can negatively impact sleep
how does spicy foods impact sleep?
- Increase body temperature. As sleep requires cooler body temperatures, spicy food impair sleep.
- Also stimulate metabolic processes making it difficult to fall asleep.
How can bright light therapy be used as a treatment for Delayed sleep phase syndrome?
An individual is exposed to the bright light source in the morning at an appropriate waking time. This will act as an external cue to the suprachiasmatic nucleus and promote wakefulness, by sending signals to release melatonin. This will help the suprachiasmatic nucleus send signals for melatonin release at an earlier, more appropriate sleeping time, thus promoting sleep.
How can bright light therapy be used as a treatment for Advanced sleep phase disorder?
An individual is exposed to the bright light source in the evening when feeling sleepy, to act as an external cue to the suprachiasmatic nucleus and promote wakefulness. This will then help the suprachiasmatic nucleus send signals for melatonin release at a later, more appropriate sleeping time, thus promoting sleep.
How can bright light therapy be used as a treatment for shift work?
The use of bright light therapy for shift work depends on the details and timing of an individual’s work. An individual is best to be exposed to the bright light source before beginning their shift work, in order to promote wakefulness when they need to be awake and alert. This will help promote sleepiness at a later, more suitable time (when they are not required to work), whether that be during the morning or afternoon.
