U4 AOS1 - Sleep

Flashcards Covering Sleep Psychology Lecture Notes (Unit 4, AoS1)

Sleep

a psychological construct that is a naturally occurring altered state of consciousness broadly categorized into REM and NREM sleep.

Psychological Constructs

Abstract concepts used by psychologists to describe and explain things we cannot directly observe or empirically measure (e.g., memory, consciousness, love).

Consciousness

a psychological construct that defines one's awareness of internal events and external stimuli, which differs across time and context.

subjective, difficult to empirically measure

Normal Waking Consciousness (NWC)

Accurate perception and experience of reality; organized, logical, agreed upon.

Altered State of Consciousness (ASC)

A state of mind distinctly different from NWC, can be naturally occurring or induced.

• intoxication

• meditation

• sleep

Perceptual Disengagement

No awareness of external sensory stimuli.

Unresponsiveness

Lack of reaction or other behavioral indicators of awareness.

Reversible

Sleepers can return to NWC if woken by a strong enough stimulus.

sleep as a psychological construct - measurable behaviours

• Physiological responses (brain-wave activity, body temperature etc)

• Cognitive functions (concentration, attention, decision making etc)

• Outcomes (health, wellbeing, performance etc)

sleep cycle

80-120 minute

90 minute average

4-5 cycles per night (8hr sleep)

NREM (Non-REM) Sleep

Sleep not characterized by rapid eye movement.

Beta Waves

awake, normal alert consciousness

Low amplitude, high frequency brain waves.

Alpha Waves

relaxed, calm, meditation, creative visualisation

Low-medium amplitude, medium-high frequency brain waves.

Theta Waves

deep relaxation and meditation, problem solving

Medium-high amplitude, low-medium frequency brain waves.

Delta Waves

deep, dreamless sleep

Highest amplitude, lowest frequency brain waves.

NREM Stage 1

• when we get tired and begin to fall asleep, betawaves transform into alpha waves

• enter a hypnogogic state - deep relaxation, flashes of vivid mental images and rolling eye movements

• low arousal threshold - if woken, dont believe we were asleep

• hypnic jerks - reflex muscle contractions

• lasts 2-10 minutes

Hypnogogic State

A state characterized by deep relaxation, flashes of vivid mental images, and rolling eye movements in NREM stage 1 sleep.

Hypnic Jerks

Reflex muscle contractions that occur during NREM Stage 1.

NREM Stage 2

• first considered to be asleep

• light sleep for 20-30 minutes

• heart rate & breathing slows, body temp decreases

• theta waves dominate

  • sleep spindles - short bursts of high frequency brain activity

  • k-complex - single large burst of high amplitude brain activity

Sleep Spindles

Short bursts of high-frequency brain activity during NREM stage 2, potentially indicating when sleep begins.

K-Complex

Single large burst of high amplitude brain activity during NREM stage 2, potentially associated with memory consolidation.

NREM Stage 3

• deep, dreamless slow wave sleeo

• delta waves dominate

• occurs about an hour after falling asleep

• lasts 20-40 minutes

• sleeper is unresponsive, if woken may be confused & disorientated

• sleep walking, bed-wetting, night terrors

REM sleep

• rapid eye movement sleep is associated with dreaming

  • 80% of dreams occur during REM

  • 85% of people woken during REM recall vivid dreams

• REM increases over the course of the night

• EEG’s register similar brain waves to when we are awake (beta-like waves)

• muscles are in atonia - muscle paralysis

• REM =paradoxical sleep as the brain is extremely active but the body is extremely calm

• lack of Atonia may result in REM behaviour disorder - acting out dreams

Methods to Assess States of Consciousness

Physiological - heart rate, temperature, brain wave activity etc.

Psychological / Behavioural - speed vs accuracy tasks, video monitoring, self reports etc.

Body Temp

NWC is 37 degrees

ASC - higher or lower than 37

Electrocardiograph (ECG)

Detects, amplifies, and records electrical activity of the heart muscle.

lower or higher BPM than avg can indicate an ASC

Electroencephalograph (EEG)

Detects, amplifies, and records electrical activity in the brain.

records amplitude and frequency of brian waves

Electrooculargraph (EOG)

Detects, amplifies, and records the electrical activity and muscle movement around the eyes.

• during NWC our eyes move and rotate depending on what we are watching/paying attention to

• during sleep, EOG can determine if we are in REM or non-REM

• EOG records high amplitude and frequency wave activity in REM and NWC

Electromyograph (EMG)

Detects, amplifies, and records the electrical activity caused by muscle movements on the skin’s surface.

• during NWC, EMG will show moderate-high muscle movement

• in REM we experience Atonia, therefore EMG readings should show low levels of activity

Speed Vs Accuracy Tasks

Behavioral alertness measured via Psychometric Vigilance Tests (PVTs).

slower reaction times usually indicate an ASC

Video monitoring

Filming nocturnal activities (snoring, restless leg syndrome, apnea, sleep walking, night terrors etc)

Self Reports

Participants freely express and record their own subjective experiences, attitudes and behaviours by answering questionnaires or surveys.

eg. sleep diary

self-report (sleep diary) - advantages & limitations

Advantages:

• More detailed information (like a case study)

• Can collect both Quantitative and Qualitative data

Disadvantages:

• Placebo Effect / Demand characteristics (people might change the way they behave due to expectations, or record certain data because they know they are being studied

• Subjective Bias – prone to personal interpretation

Polysomnography

Study of sleep that uses devices to collect objective data often in Sleep Laboratories.

ECG

EEG

EMG

EOG

DARE - detects, amplifies and records electrical activity of

Sleep Laboratories

provide a controlled environment to electronically observe and measure sleep behaviours and disorders using various devices.

While artificial, they are designed to be homely, natural and comfortable to promote normal sleeping behaviours

Sleep Lab - Advantages & Limitations

Advantages:

• Quantitative, objective, numerical data – Controlled environment

Disadvantages:

• Artificiality’ – participants’ behaviour may be affected by the unnatural environment / may not be an accurate representation

Circadian Rhythm

Our body clock cycle that regulates automatic physiological changes that occurs every 24 hours to maintain homeostasis and healthy equilibrium.

sleep-wake cycle is a circadian rhythm that works in sync with the external day-night cycle

Ultradian Rhythms

Repeated biological cycles that occur less than every 24 hours.

• sleep stages

• eye blinks

• heartbeats

Suprachiasmatic Nucleus (SCN)

Located in the hypothalamus, regulates our internal biological-clock (circadian rhythm).

activated by zeitgebers

Zeitgebers

External/environmental cues such as , temperature, noise, food etc, which elicit biological cyclical changes and activate the SCN.

Biological process of sleep

Zeitgebers activate the SCN which signals the Pineal Gland to regulate body rhythms and sleep cycles.

Pineal gland releases Melatonin - a hormone triggered by darkness that causes drowsiness

Melatonin

A hormone triggered by darkness that causes drowsiness and is released by the Pineal Gland.

sleep across the lifespan

• Across the lifespan the amount of night-time sleep decreases as we get older.

• The proportion of time spent in REM sleep also decreases as we age.

Infancy/childhood

newborns - 16 hour sleep/day (50% is REM)

by age 2 - total sleep time drops to 12-13 hours/day (25-30% REM)

childhood (age 10) total daily sleep drops to 10 hours (20-25% REM)

Adolescence

• teenagers need 9 hours of sleep/day

• tend to go to bed later and have difficulty waking up in the mornings

  • tiredness, lethargy, lack of motivation, irritability

• sleep deabt

Adolescent Sleep-Wake Cycle Shift

The body clock shifts forward and pushes the onset of sleep back later in the night during adolescence.

Biological factors of adolescent sleep-wake cycle shift

puberty causes melatonin to be released 1-2 hours later

Environmental factors of adolescent sleep-wake cycle shift

staying up later to socialise, finish homework, part time jobs etc

Adulthood

• timing of tiredness resets & adults get sleepy 1-2 hours earlier than teenagers

• adult demands 7-8 hours/night

• average night consists of 5 90-minute cycles

Elderly

• by late adulthood (65+), total sleep time drops to approx 6-7 hours per night

• sleep becomes lighter, with more awakenings during the night

• stage 3 is rarely experienced

Sleep deprivation

going without sleep (partially or totally) for a short or long period of time can result in adverse physical and mental effects

Total Sleep Deprivation

No sleep for a 24 hour period.

Partial Sleep Deprivation

Less than average/normal (7-9 hours) of sleep.

Sleep deprivation: frontal lobe effect

sleep deprivation dampens our frontal lobe activity and the effectiveness of our working memory

ability to control and direct attention while performing cognitive tasks that require planning, decision making and problem solving becomes compromised

Sleep deprivation: short term effects

• Sore, drooping eyes, staring, poor focus

• Trembling hands, lack of coordination

• Increased discomfort, headaches and pain sensitivity

Sleep deprivation: long term effects

• Less glucose metabolized – less energy and endurance

• Increased appetite and chance of obesity

• Disrupted physical growth

• Weakened immune system – vulnerability to infection and disease.

Partial sleep deprivation - affective

• Amplified or diminished emotional

• a single night of sleep deprivation results in decreased positive mood (empathy, joy, patience, friendliness) and

• increased negative mood (aggression, irritability, temper)

• more vulnerable to stress, anxiety and depression.

Partial sleep deprivation - cognitive

• Poor CONCENTRATION – difficulty maintaining focus and attention

• Poor problem solving and decision making

• Increased confusion, disorientation and paranoia

  • Sleep Deprivation Psychosis – a temporary state of impaired mental functioning that can include delusions and hallucinations.

• Speed and accuracy on psychometric vigilance tests (PVTs) are diminished

• Impacts Automatic Processes MORE than Controlled Processes

• More likely to affect the performance of simple, routine, automatic tasks than complex ones (hence dangerous for drivers, machine operators etc).

• people compensate to concentrate to perform interesting, complex tasks but don’t pay the same attention to routine ones.

Partial sleep deprivation - behaviour

• Impaired ability to regulate appropriate actions and responses

• Poor coordination, fine motor skills (clumsiness)

• Slower reflexes and reaction times

• Difficulties completing routine tasks

• For students at school this could

  – Increased disruptiveness, rudeness, naughtiness and risk-taking

  – Increased lateness and absenteeism
  – Decreased engagement and participation

Sleep Deprivation Psychosis

A temporary state of impaired mental functioning that can include delusions and hallucinations caused by sleep deprivation.

Microsleep

A short period of loss of consciousness that can occur as a result of sleep deprivation while a person is apparently awake.

REM Rebound

We will automatically spend more time in REM sleep immediately after a period of lost sleep or sleep deprivation to recover, compensate, or catch-up.

Recovery

A single night of uninterrupted sleep can reverse or correct most symptoms of sleep deprivation.

• Hence you don’t need to make up for all the hours you have lost to function properly again.

• Usually there is no permanent damage.

Case study - Randy Gardner

• set the world record for staying awake 264 hours (11 days), during which he suffered debilitating psychological and physical effects.

• after, he slept for 15 hours the first night, 12 hours the second and 10.5 the third before returning to normal.

• He suffered no consequences.

0.05 BAC equals…

17 hours awake

0.10 BAC equals…

24 hours awake

Sleep Disturbances

Problems with sleep quantity or quality that usually relate to disruptions to normal sleep-wake cycles.

Sleep Disorders

Syndromes that consistently disrupt the quantity and quality of normal NREM-REM cycles and the restorative function of sleep, affecting healthy physiological, psychological and social functioning.

Circadian Rhythm Sleep Disorders

Disorders that disrupt one’s biological body clock and result in people operating out of ‘sync’ with their environmental conditions.

internal sleep-wake cycle is not aligned with their external day-night cycle

daytime effects of circadian rhythm sleep disorders

• lethargy

• excessive tiredness

• poor concentration

• problems with learning & memory

nighttime effects of circadian rhythm sleep disorders

• difficulty falling asleep,

• maintaining sleep,

• waking frequently

Delayed Sleep Phase Syndrome (DSPS)

Occurs when a person’s circadian rhythm is pushed forward or delayed, resulting in a tendency to get tired and sleep later than normal.

symptoms of DSPS

• sleep onset insomnia

• difficulty waking

• excessive day-time sleepiness

example of DSPS

adolescent sleep wake cycle shift

causes an accrual of sleep debt

Advanced Sleep Phase Disorder (ASPD)

Occurs as a result of early sleep onset, going to sleep earlier and waking up earlier compared to typical sleep patterns.

symptoms of ASPD

• maintenance insomnia

• extreme tiredness in the evening

• daytime lethargy

Shift Work

Involves hours of paid employment that fall outside of the normal sleep-wake cycle and requires people to be alert and active out of phase with their circadian rhythm.

As their internal circadian rhythms (sleep-wake cycle) are no longer synchronised with the external environmental day-night cycle, they are forced to …

operate in contradiction to the increased Melatonin (which makes them tired) or increased Cortisol (which makes them aroused) in their system

Bright-Light Therapy

Exposes patients to safe levels of artificial light to help synchronize their internal sleep-wake cycle with environmental day-night cycles.

when bright-light therapy should be exposed

DSPS - early in the morning

ASPD - early in the evening

shift work - start of a night shift

Sleep Hygiene

Routines or behaviors designed to encourage optimal sleeping outcomes and mental well-being.

examples of sleep hygiene

• nightly ritual

• go to bed and wake up at the same time

• regular exercise

• exposure to natural light in the morning

• avoid napping

• avoid stimulating activities before bed

Stimulus-Control Therapy

Breaks learned associations between the bed/bedroom and activities that are inappropriate to a conducive sleeping environment.

• eg use classical conditioning to help an insomniac only associate the bed/bedroom with sleeping

Daylight & Blue Light - sleep hygiene

Blue light = Light that has low wavelengths on the visible light spectrum and is emitted by the sun and artificial light sources.

has the greatest ability to inhibit the release of melatonin

temperature - sleep hygiene

hypothalamus (SCN) regulates homeostasis and body temperature

19-21 degrees is optimal range

eating and drinking patterns - sleep hygiene

foods release eneergy that arouses you and digestion is more efficient earlier in the day

avoid certain substances before bed - stimulants (caffeine, nicotine) - delay sleep onset and depressants (alcohol) - causes arousal when it wears off