sleep

SLEEP

Year 12 Psychology Unit 3 – The Conscious SelfArea of Study 1: Mind, Brain and BodyChapter 3 (pages 96 to 131)

SLEEP A regularly occurring

altered state of consciousness: Typically occurs spontaneously; Characterised by loss of conscious awareness.

Just like Normal Waking Consciousness, sleep has different levels/states: Dreaming is a different state of consciousness to sleeping

without dreaming. Over a lifetime, we spend about one-third of

our time asleep. If we live to around 75 years old, we will spend about 25 years sleeping (including about 5 years dreaming).

THINGS YOU NEED TO KNOW ABOUT SLEEP

Methods Used to Study Sleep: EEG, EMG, EOG.

Characteristics/Patterns of Sleep: NREM stages 1 to 4, REM.

Sleep Deprivation: Psychological & Physiological effects.

Sleep Phenomena: Nightmares, Night Terrors, Sleepwalking, Sleep

Talking. Sleep Disorders:

Insomnia, Hypersomnia, Sleep Apnea.

METHODS USED TO STUDY SLEEP Most sleep research happens in sleep

laboratories (also known as sleep study units). These are made as homelike & comfortable as

possible to avoid extraneous variables.

Sleep laboratories use EEGs, EMGs and EOGs to record brain activity, eye movements and muscle tension during sleep stages.

It is also useful to wake participants at different stages and ask them to describe their experiences.

METHODS USED TO STUDY SLEEP:

ELECTROENCEPHALOGRAPH (EEG) Detects, amplifies & records the electrical activity

spontaneously generated by the brain.

As a person falls asleep, & through a typical sleep period, the brain produces distinguishable patterns of electrical activity (brain waves).

EEG studies have shown that we all experience 5 different stages of sleep in a typical night.

Physiological changes such as muscle tension correspond to changing brain wave patterns.


ELECTROMYOGRAPH (EMG) Detects, amplifies & records the electrical activity

of muscles.

Recordings indicate changes in muscle activity (movement) & muscle tone (tension).

Recordings are obtained by attaching electrodes to the skin above the particular muscle/s.

EMG studies show that our muscles progressively relax as we pass into deeper stages of sleep. There are also periods where our muscles may spasm (light sleep) or completely relax (deep sleep).


ELECTRO-OCULOGRAM (EOG) Detects, amplifies & records the electrical activity

of eye muscles that control eye movements & positions.

Most commonly used to measure changes in eye movements during different stages of sleep.

Recordings are obtained by attaching electrodes to areas of the face surrounding the eyes.

EOG studies have allowed researchers to distinguish between two different types of sleep: Rapid-eye-movement sleep (REM); Non-rapid-eye-movement sleep (NREM).

CHARACTERISTICS & PATTERNS OF SLEEP

During a typical night’s sleep we experience two different types of sleep: NREM & REM.

In adults, one cycle of NREM sleep lasts for about 70 – 90 minutes, containing four different stages. A period of REM sleep follows each NREM cycle.

A complete sleep cycle usually lasts for about 80 to 120 minutes: NREM sleep (not necessarily all 4 stages) followed by

a period of REM sleep (which usually increases in length as the night continues);

We usually go through the complete cycle approximately 4 or 5 times during 8 hours of sleep.

CHARACTERISTICS & PATTERNS OF SLEEP:

NREM SLEEP 80% of our sleep time, typically more in first half

of the night. Brain is active (as shown by EEG) but not as

active as in REM sleep or normal waking consciousness.

Theory: NREM sleep may be the time when the body recovers, repairing body tissue, removing waste products & replenishing neurotransmitters. After strenuous physical activity, NREM sleep

increases. What are the effects on the body of not getting

enough NREM sleep?


NREM SLEEP Four different stages which progress through

the night from lightest to deepest & back again through one or more stages to lightest.

We can identify which stage of sleep someone is in by looking at their brain waves (each stage is associated with different brain waves).

Brain waves are measured by frequency (speed – number of waves per second) & amplitude (intensity – size of the waves).


NREM SLEEP When we first close our eyes & begin to relax

before falling asleep, our brain emits bursts of alpha waves.

Alpha Waves: associated with relaxation & drowsiness (high frequency, medium amplitude).

This is known as the hypnogogic state. Slow, rolling eye movements; 1 – 2 minutes; May experience flashes of light or colour, floating or

weightlessness, dreamlike images, jerky movements, falling sensations.

CHARACTERISTICS & PATTERNS OF SLEEP: NREM SLEEP

NREM – STAGE 1 Gradually lose awareness of ourselves & our

surroundings, but sometimes aware of faint sounds in our environment.

Decrease in heart rate, respiration, body temperature & muscle tension.

Hypnic Jerk: muscles spasm/jerk as a result of relaxing – very common in stage one.

Decrease in alpha waves, replaced by more theta waves (irregular, medium frequency, high and low amplitude).

Lasts 5-10 minutes, if woken during this stage we may feel we haven’t slept at all.


NREM – STAGE 2 Light stage of sleep (easily woken), the point

when someone can be said to be truly asleep. Body movements lessen, breathing becomes

more regular, blood pressure & temperature continue to fall, heart rate is slower.

Mainly theta waves, but slightly lower frequency & higher amplitude than the stage one waves.

Sleep Spindles: brief (1 second) bursts of high frequency – indicate person is truly asleep.

K Complexes: bursts of low frequency, slightly higher amplitude waves in response to stimuli.

Lasts 10 – 20 minutes, if woken say “dozing”.


NREM – STAGE 3 Start of deepest stage of sleep (moderately deep). Heart rate, blood pressure, body temperature

continue to drop & breathing rate continues to be slow & steady.

Extremely relaxed & becomes increasingly less responsive to the outside world (difficult to wake).

Delta waves begin to appear: slow, large, regular. This marks the start of slow wave sleep (SWS).

SWS usually starts within an hour of falling asleep & last for about 30 minutes.

When delta waves make up more than 50% of brain activity, have entered stage 4 sleep.


NREM – STAGE 4 Deepest stage of sleep (very deep sleep). Stage when sleepwalking, sleep talking, night

terrors & bedwetting can occur. Muscles are completely relaxed; we barely move. Delta waves, even bigger & slower than Stage 3. Very difficult to wake – ‘out like a light’. In first sleep cycle, may last 20mins, but become

progressively shorter through the night. Sleep inertia (aka ‘sleep drunkenness’): when

woken, may take up to 10mins to orient themselves & usually have poor memory of sleep events.


REM SLEEP Period of rapid eye movement during which the

eyeballs move rapidly beneath closed eyelids. Irregular beta wave, high frequency & low

amplitude – similar to waking brainwaves, but still considered as deep sleep because difficult to wake.

Internal functioning becomes more active but body remains completely relaxed: paradoxical sleep.

Most dreaming occurs in this stage – some believe that our body enters ‘paralysis’ to prevent us from acting out our dreams.

No clear reason as yet for the eye movements.


REM SLEEP Psychologists agree REM has a purpose, but it is

still relatively unclear what that may be: Strengthening newly formed neural connections (to

aid in consolidating/embedding memories) – this has only been proven for memory of motor tasks, not verbal;

Important role in maturation of nervous system.

People who have been deprived of REM sleep remain in the stage for longer than normal when given the opportunity- ‘catching up’ on REM.

Infants & children spend a significant proportion of their sleep in REM, compared to adults.

SLEEP DEPRIVATION Going without sleep. Results in range of uncomfortable feelings:

Irritability, tiredness, headaches, lack of concentration, motivation & energy.

Extent of discomfort depends on individual, amount of sleep lost & period of time over which sleep deprivation occurred.

Unethical to deprive humans of sleep for extended periods, so research is done on animals.

Research on humans only involves partial sleep deprivation & ethical considerations must be strictly observed.

Pg 164: add definitions of total and partial sleep deprivation

SLEEP DEPRIVATION:

PSYCHOLOGICAL EFFECTS Lack of concentration, moodiness,

irritability, heightened anxiety, lack of motivation.

Significantly impaired short-term memory. Depression, hallucinations, delusions, paranoia.

Prolonged sleep deprivation can cause: Impaired ability to perform cognitive tasks; Slower reaction times on motor tasks; Illogical & irrational thinking; Difficulty making decisions or solving problems that

require creative thinking.*Read examples Pg. 305

SLEEP DEPRIVATION:

PHYSIOLOGICAL EFFECTS Sleepiness & fatigue. Hand tremors, drooping eyelids, difficulty

focusing the eyes, lack of energy/strength, slurred speech, increased sensitivity to pain.

Impaired immune system & production of certain hormones by the endocrine system.

After a continuous waking period of five days & nights: heart & respiratory system slows; body temperature drops.

*Read examples Pg. 306

SLEEP DEPRIVATION:

ADDITIONAL INFO. & ISSUES Total sleep deprivation is difficult to study

because after three or four sleepless days, people automatically drift into microsleeps.

Microsleep: very short period of drowsiness or sleeping that occurs while person seems ‘awake’. May have no recollection upon waking.

Effects of sleep deprivation are temporary & usually persist only until individual sleeps.

Do not need to fully compensate for sleep lost – most can just get a few extra hours that week.

SLEEP WAKE CYCLE SHIFT DURING ADOLESCENCESLEEP- WAKE CYCLE: A shift of the body clock, forward or backward in time, affecting an

individual’s normal/regular sleep onset time and biologically required waking time.

LIFESPAN SLEEP WAKE CYCLE: children: about 12–13 hours total sleep time, 25–30% REM adolescents: about 9 hours total sleep time, 20% REM adults (late adulthood): about 6-7 hours total sleep time, 33% REM

DURING ADOLESCENCE: A shift of the biological body clock forward by about 1-2 hours,

resulting in the delayed onset (sleep phase onset) of sleep by 1-2 hours

But early starts prevent a sleep-in to have the additional sleep that would naturally occur. Sleep loss onset occurs – can accumulate as a sleep debt.

:Definition of sleep debt

SLEEP WAKE CYCLE SHIFT DURING ADOLESCENCE

CONSEQUENCES OF SLEEP_WAKE CYCLE FOR ADOLESCENTS

difficulty waking up (e.g. to go to school or work)

erratic sleep patterns sleep deprivation lethargy impaired cognitive functioning during waking

hours negative moods self-control (difficulties controlling behaviour) low grades and poor school performance.

THE REMAINDER OF THE PRESENTATION IS NOT ASSESSABLE

OR EXAMINABLE CONTENT.

SLEEP PHENOMENA Observable experiences that occur

during sleep & may have the potential to disrupt sleep.

If they occur often & disrupt sleep, they are considered to be sleep disorders.

Much more common in childhood & adolescence, but adults may also experience them, usually during times of stress or major life events.

SLEEP PHENOMENA:

NIGHTMARES Unpleasant dreams with content that is

frightening or upsetting (usually afeeling of helpless terror).

Able to be recalled on awakening, often vividly, because we often wake up during the nightmare.

Usually occur during REM sleep, so the body is stationary (due to REM-related ‘paralysis’).

No visible difference to indicate what sort of dream is being experienced by the individual.

SLEEP PHENOMENA:

NIGHTMARES Experienced more commonly by children

than adults; females are twice as likely to have nightmares.

More likely to occur during times of high stress, fatigue, or when we have experienced personal trauma of some kind.

Not necessarily associated with any psychological disturbance, but the reason for nightmares is still no fully understood.

SLEEP PHENOMENA:

NIGHT TERRORS Sudden awakening from sleep in an extreme

state of distress, little or no bodily movement & little or no recall of what caused the terror.

Sufferers may wake screaming, sweating, with dilated pupils, rapid breathing, greatly increased heart rate & a terrified expression on face.

Sufferers may also speak incoherently & walk around in a state of panic.

While in the distressed state, sufferers are often difficult to console.

SLEEP PHENOMENA:

NIGHT TERRORS Tend to occur less frequently than

nightmares but are more distressing. More common in pre-school children (3-5 years),

especially boys, but sometimes adults may experience a milder form.

Occur during stages 3 & 4 of NREM sleep, so more likely to occur earlier in the night when sleep cycle contains longer periods of these stages.

Children usually stop getting night terrors as they get older, possibly because adults experience less NREM stage 3 & 4 sleep than children do.

SLEEP PHENOMENA:

SLEEPWALKING Walking while asleep & sometimes

conducting routine activities (e.g. dressing, eating.)

Also known as somnambulism.

Most commonly observed in children before they reach puberty, but is not unusual in adults, especially during times of high stress.

Usually last 5-15mins, but can go for half an hour.

SLEEP PHENOMENA:

SLEEPWALKING (SOMNAMBULISM) Usually occurs in stages 3 & 4 of NREM

(delta waves – deepest sleep), so poor coordination, incoherent language & difficult to wake.

Generally unresponsive to environment or others.

It is not dangerous to wake them, but they will often go back to bed if left alone.

Watch the clip…Sleepwalk

SLEEP PHENOMENA:

SLEEP TALKING Verbalisation (talking) during sleep.

Usually mumbling, but may also be recognisable words, phrases or sentences.

Usually unable to answer questions or engage in logical conversation, although sometimes they may be able to converse with someone for a short time.

Watch the clip…Sleep Talk

SLEEP PHENOMENA:

SLEEP TALKING Often unaware they have talked in

their sleep, unless they wake while they are talking (in which case they often can recall what they were saying).

Very common: occurs at one time or another in most people.

Can co-occur with sleepwalking. Watch the clip…Sleepwalk & Sleep Talk

SLEEP DISORDERS Any sleep problem that disrupts the

normal NREM-REM sleep cycle, including the onset of sleep.

May involve persistent difficulties in falling asleep, staying asleep, waking up or staying awake.

If sleep phenomenon recur & disrupt sleep, they are also considered to be sleep disorders.

Sleep disorders typically cause personal distress & often interfere with normal functioning, but can almost always be successfully treated.

SLEEP DISORDERS:

INSOMNIA Continually getting insufficient or

poor-quality sleep. Three patterns of insomnia:

Sleep-onset insomnia (difficultly falling asleep); Sleep-maintenance insomnia (difficultly staying asleep

OR awakening prematurely from sleep) As well as disrupted sleep, many other symptoms:

Failure to fall asleep within 30minutes of intending to; Waking for longer than 30minutes during the night; Consistently reduced total amount of sleep; Complaint of poor sleep; Feeling tired during the day.

SLEEP DISORDERS:

INSOMNIA Insomnia is diagnosed if one or more of the

disruptive sleep patterns is present in conjunction with some of the specific symptoms for at least 50% of the time over several weeks.

Insomniacs show more body movements during sleep, plus higher heart rate & body temperature. There is usually an underlying reason for not being able to sleep.

Causes may be psychological or physiological.

SLEEP DISORDERS: INSOMNIA

CAUSES Psychological causes:

Stress, fear, anxiety surrounding a specific problem can lead to short-term insomnia (e.g. relationship problems, loss of someone close) – once problem passes or is no longer a factor, insomnia ceases.

Excessive stress/worry about not being able to sleep can turn short-term insomnia into long-term.

Fear of dying during sleep, nightmares or not waking up can also create insomnia.

Physiological causes: Medical problems, some medications, severe &

persistent pain, excessive alcohol or drug use, changes to sleep schedule.

SLEEP DISORDERS: INSOMNIA

TREATMENT Medication:

Decrease the amount of stage 4 NREM & REM sleep. May assist in short-term, but can cause drowsiness.

Dealing with underlying cause. Relaxation or stress-management strategies. Developing regular sleep routines. Exercising regularly. Increasing melatonin levels:

Hormone plays important role in regulating natural bodily rhythms (e.g. sleep-wake cycle);

Research shows it can help in the short-term, but further research is needed to determine long-term.

SLEEP DISORDERS:

HYPERSOMNIA Excessive sleepiness while awake (regardless of

how long they sleep), or excessive sleep duration. Sufferers often require more than 12 hours sleep

per night & have extreme difficulty waking. Sleep onset typically occurs within seconds after

going to bed & they may be confused or disoriented upon waking.

May be chronic or only occur 3 or 4 times a year. Insomnia, depression, drug abuse & sleep apnea

can all result in hypersomnia. If condition is chronic it may have a profound

effect on the individual’s ability to function.

SLEEP DISORDERS:

SLEEP APNEA Temporary suspension (stop) in breathing for short

periods (30s – 2mins) during sleep. Usually ends in a loud snore, body jerk or arm

flinging, or by sitting upright. Usually wake up long enough for breathing to

return to normal, then fall asleep again.

Sufferers may have their sleep interrupted hundreds of times each night, but not recall these interruptions in the morning.

Sufferers often feel chronically tired during the day & show a decline in attention & learning abilities.

SLEEP DISORDERS:

SLEEP APNEA Two main causes:

Failure of the ‘breathing centres’ of the brain; Narrowing of the airway into the body;

Obstruction, excess fatty tissue around neck, illness, medication, shape of jaw/throat/nose.

Treatment depends on cause: Tranquilisers to relax throat muscles; Surgery to clear obstructions; Dental appliances to reposition tongue; Nasal mask & pump to maintain regular breathing.

May also be a due to level of acetylcholine in the brain – further research is being done in this area.

SO WHAT HAVE WE LEARNED ABOUT SLEEP… Sleep is a lot more complicated than it

seems! 5 stages of sleep (4 x NREM, REM); Different brain waves (alpha, beta, theta, delta); Sleep phenomena (x 4) & sleep disorders (x 3).

It’s really important to get a good night’s sleep, otherwise you can suffer physiological & psychological effects of sleep deprivation…

…otherwise, you might end up like this kid…Laughing Baby

sleep

Documents

sleep stages

sleep laboratories

sleep phenomena

sleep apnea

sleep deprivation

sleep disorders

sleep year

deep sleep