Characteristics of Altered States of Consciousness

Characteristics of Altered States of Consciousness

Characteristics of Altered States of Consciousness

Most people spend about two thirds of the day in normal waking consciousness.

When a person notices their level of mental functioning changing they are usually entering an altered state of consciousness.

Altered States of Consciousness The term altered state of consciousness

refers to any state of consciousness which is distinctively different in level of awareness and experience from NWC, in terms of level of awareness and experience, the quality and intensity of sensations, perceptions, thoughts, feelings, and memories that are experienced.

In an ASC mental processing shows distinct changes specific to that particular state.

Altered States of Consciousness Some ASC’s are natural – sleep & dreaming

Others are purposely induced – meditation, hypnosis, drug taking

Humans induce ASC for relaxation, therapy, or escapism from pressures in their lives

Common characteristics of ASC’s:-Distortions of perception & cognition,-Disturbed sense of time, -Changes in emotional feeling, changes in self control

1. Distortions in perception and cognitionAn ASC seems to have two effects on the senses- it either

makes them more receptive or dulls them so that some sensations are not experienced at all.

Some drugs heighten sensory experience ie, colours seem brighter, tastes and smells stronger, sounds louder or more variable, and touch more sensitive, whereas meditation can dull our experience of pain.

Distortions in perception

Perceptions are often so distorted in an ASC that people may lose their sense of identity (who they are) or experience the feeling of being outside their body or someone else entirely. This can occur with the use of the drug Ketamine.

Ketamine & Out of body Experiences What Is Ketamine? Ketamine is an anesthetic used on both

animals and humans; it also has been used in human medicine for pediatric burn cases and dentistry, and in experimental psychotherapy. It is being abused by an increasing number of young people as a "club drug," and is often distributed at "raves" and parties.

Distortions in Cognition Thought processes are often more disorganised

during a waking ASC, as well as during dreaming. In an ASC:-thinking is often illogical and lacking in sequence-difficulties may be experienced in problem-solving-people may have trouble remembering events that

have occurred in an ASC. When consuming alcohol people are often unable to

recall the events that occurred while intoxicated. Marijuana use can also impair short term memory

and thinking.

Meditation & Cancer

Meditation specialists believe visualisation and guided meditation can help cancer sufferers gradually remove cancer.

2. Disturbed sense of time

Estimation of time is frequently distorted in an ASC

Time passes at a different speed than normal Either faster – Eg sleeping for 8 hours and it

feels like 30 mins or vice versa

Think…

Have you ever seen a person under the influence of alcohol or drugs, who has shown completely different emotional responses that they normally would?

3. Changes in emotional awareness ASC’s can put peoples emotions into a state

of turmoil resulting in uncharacteristic responses

Eg. Under the influence of alcohol some people display their feelings/emotions more freely while others can become quite aggressive

In other ASC’s people have reported feeling emotionless; that is having no feelings at all.

In some ASC’s people may have inappropriate emotional reactions. Eg. laughing at hearing the news of a friends death or crying at a joke.

Think!

Have you ever witnessed someone under the influence of alcohol or drugs who has shown a complete lack of self control?

4. Changes in self-control

Changes in our ability to maintain self-control are often evident during ASC’s

Eg. In an alcohol induced state people may have difficulty coordinating and controlling movements (stumbling).

In a hypnotic state, some people are more open to suggestion.

STATES WITHIN ALTERED STATES OF CONSCIOUSNESS

Daydreaming

Daydreaming is an ASC in which we shift our attention from external stimuli to internal, thoughts, feelings and imagined scenarios.

The shift occurs naturally and usually without being aware.

More likely to occur when you are stationary than when you are moving around.

Different from a night dream physiologically- minimal eye movement and alpha waves present.

Daydreaming

There are many proposed purposes for daydreaming such as:

- Freud believed it was to allow us to do in our fantasies what we are unable to do in reality.

- Singer (1975) proposed that daydreaming enables us to mentally try out a range of courses of action that could be applied to certain situations.

- He also suggested it can help us to solve problems. - Some suggest we daydream to stay mentally alert in

situations in which there is insufficient external stimulation.

Alcohol-induced state

What is alcohol?Usually refers to drinks such as beer, wine or

spirits containing ethyl alcohol- a substance that can cause drunkenness and changes in consciousness, mood and emotions.

Ethyl alcohol requires no digestion and seeps into the bloodstream via the gastrointestinal tract.

Alcohol is considered a psychoactive drug. These are chemicals that change conscious awareness, perception or moods.

Alcohol is also classified as a depressant meaning that although it initially produces a mild euphoria, it lessons our inhibitions and depresses the activity of the brain centers.

Effects depend on the concentration of alcohol consumed, the amount, and variables related to the individual.

The effects of alcohol on consciousness: a shortened attention span

impaired perceptions impaired thinking impaired memory slower reaction times reduced self-awareness impaired emotional awareness impaired perception of time less self-control difficulty with voluntary muscle control and fine movements deterioration in performance of complex tasksTable 2.4 pg 120

Practising meditation

The experience of pain is less intense and meditation can provide relief from pain in some cases.

Brainwaves experienced in meditation are similar to those people experience when falling asleep or when they are actually asleep.

Meditative state

Many forms such as yoga, Zen and transcendental meditation each of which has its basis in Eastern religion like Buddhism and Hinduism.

Meditation involves the use of a technique to deliberately alter NWC in order to induce an ASC characterised by a deep state of relaxation.

It typically involves altering the normal flow of conscious thoughts by focusing on a simple stimulus like breathing or a body part.

Measuring states of consciousness

Can you think of how we measure states of consciousness?

Measuring physiological responses of consciousness A state of consciousness cannot be measured

directly like physical characteristics.

It is because of this that it is called a psychological construct.

A psychological construct is a concept used to describe something that is believed to exist, but that cannot be directly observed or measured.

Measuring states of consciousness 1. Self-report: limited because subjective:

individuals may- be dishonest, struggle to articulate, forget details

2. Behavioural observations: limited because can’t observe inside the body

Measuring states of consciousness

SO! Psychologists usually rely on measuring…

3. Physiological responses: Useful as objective. Limited: may indicate illness or multiple ASCs Heart rate: ASC usually ↓, e.g. sleep; can ↑, e.g. stimulant drugs GSR: positive correlation with arousal Body temperature: drops ~1°C during sleep, high temps (e.g.

fever) can induce ASC EEG: electrical activity within the brain is graphed

1. EEG

Electrical Activity of the Brain Brain wave patterns

form EEG readings. Vary in:

Frequency – brainwaves per second

Amplitude – size of the peaks and troughs

High Frequency Low Amplitude

Electrical Activity of the BrainThe size and number of brain waves change with different states of

consciousness:

Normal waking consciousness – Beta waves: High frequency, Low amplitude (Ie. Lots of waves but not very high)

Extremely relaxed – Alpha waves: High Frequency, Larger amplitude

Early stages of sleep – Theta waves: Medium frequency, Some high amplitude

Deep Sleep – Delta waves: Low Frequency, High amplitude

Remember!

B (wide awake)ATD (fast asleep)

Remember!

Beta: Busy Brain – awake & alertAlpha: Almost Asleep – restingTheta: They’re asleepDelta: Deep Sleep – also know as

slow wave sleep

Brain Waves Patterns

2. Heart Rate

May increase or decrease in an ASC.

While a person is asleep, unconscious or meditating, heart rate is likely to decrease.

When a person is experiencing ASC’s associated with the use of substances that are stimulants, heart rate is likely to increase.

3. Body Temperature

Body temperature is less variable than heart rate; however there is a general pattern indicating changes in body temperature in altered states.

The most obvious change is during sleep; body temperature drops by more than 1°C while asleep.

4. Galvanic Skin Response

The theory is that; the more relaxed you are the dryer your skin is and so the higher the skins electrical resistance. When you are under stress your hand sweats and then the resistance goes down.

3. Galvanic Skin Response The galvanic skin response is a physiological

response that indicates the change in the resistance of the skin to an electrical current.

Electrical conductivity increases as physiological arousal increases.

To measure the GSR electrodes are attached to the finger or the palm of the hand as these areas have less hair.

The electrodes enable detection and measurement of how easily the electrical current passes through the skin.

Changes in the GSR are closely associated with emotional experiences.

An individual may show high arousal (and thus less resistance) when stressed in an exam (NWC) or when on drugs (ASC). Thus, GSC can not be used solely as an indication of what state of consciousness a person is in.

Using one form of measure can be misleading as anxiety or illness can change the measure and may not reflect the actual state of consciousness. Experts therefore use a number of measures at one time including self reports.

ASC: Sleep

Sleep is studied in a sleep lab

Sleep During the altered states of consciousness associated

with sleep, our awareness and our perception of ourselves and the events occurring around us differ from when we are awake and in a state of normal waking consciousness.

Just as there are different levels of awareness within NWC, when we sleep we also experience different states of consciousness.

Eg. When we dream while asleep we experience a distinctly different state of consciousness than that of when we are asleep but not dreaming.

Sleep

Sleep can be described as a regularly occurring altered state of consciousness that typically occurs spontaneously and is primarily characterised by a loss of conscious awareness.

Although sleep usually occurs naturally it can sometimes be induced.

Sleep

Over a lifetime we spend about one third of our time asleep.

If we live to around 75 years of age we will spend about 25 years of that sleeping.

Methods used to study sleep

Most sleep research takes place in sleep laboratories.

These are often attached to hospitals.

The ‘bedroom’ is attached to a control room where the researchers will observe and monitor sleep patterns throughout the night.

Methods used to study sleep Research participants go to sleep at their normal

time and follow their normal routine before going to bed.

The laboratory is fitted with devices to monitor and record various physiological responses of the sleeper during the course of the night.

This is often called polysomnography. Polysomnography is an intensive study of a sleeping person involving simultaneous monitoring and recording of various physiological responses of the sleeper during the course of the night.

Methods used to study sleep The main sources of data that provide information

about a persons sleep patterns are:- Electrical activity of the brain- Information about eye movements- The body’s muscle tone or tension- Heart rate - Body temperature- Respiration- Video monitoring- Self-reports

Ways to study the physiology of sleep: EEG: electroencephalogram:

Record of changes in electrical potential in the brain.

EMG: electromyogram: record of muscle tension beneath the chin.

Electro-oculogram: record of spontaneous eye movement.

Ways to study sleepElectro=electrical impulseGram=graphEach detects, measures, amplifies and records

electrical activity in graph from. EEG: electroencephalogram

halo=head=brain activity EOG: electro-oculargram

Ocular=optic=eye movement EMG: electromyogram

Myo=muscle activity

Each term hassame startand end.

Use middle as cue.

EEG patterns during sleepAn electroencephalograph (EEG) is a device that detects, amplifies

and records the electrical activity that is spontaneously generated by the brain.

EEG recordings show that as a person falls asleep, and throughout a typical sleep period, the brain produces distinguishable patterns of electrical activity called brain waves.

EEGs discussed in terms of:

Amplitude – height or size of wave

Frequency –number of waves per second

EMG patterns during sleep

The electromyograph (EMG), is a device used to detect, amplify and record the electrical activity of muscles.

EMG recordings generally show the strength and electrical activity occurring in the muscles, which indicates changes in muscle activity (movement) and muscle tone (tension).

This information is obtained by attaching electrodes to the skin above the particular muscles whose activity is being monitored.

EMG patterns during sleep These records are displayed as line graphs.

Similar to the EEG recordings, EMG records show that there are identifiable changes in muscular activity during the course of a typical night’s sleep.

Eg. There are periods of time when our muscles are very relaxed whereas at other times our muscles go into spasm.

EOG patterns during sleep The electro-oculargram (EOG) is a device for

measuring eye movements or eye positions by detecting, amplifying and recording electrical activity in eye muscles that control eye movements.

The records of the EOG are also recorded on a line graph.

They have lead psychologists to clarify the difference between two main types of sleep pattern- rapid-eye movement sleep and non-rapid-eye movement sleep.

Heart rate and core body temperature Both heart rate and core body temperature

gradually drop as we progressively drift from lighter sleep to deeper sleep and then gradually increase as we come out of deeper sleep into lighter sleep.

Unlike body temperature, there can be sudden and quite dramatic changes in heart rate. These are commonly associated with dreaming, or sleep phenomena like nightmares and night terrors or sleep disorders like sleep apnea.

Video monitoring

Most sleep labs are also fitted with video monitoring to observe any external physiological changes.

These use modern technology to film in low light and allow researchers to replay and analyse sleep behaviour.

This is particularly useful with participants who have a serious sleep disorder.

Self-reports Most commonly sleep diaries and questionnaires. A sleep diary is a self-reported record of an individuals

sleep and waking time activities, usually over a period of several weeks.

Things that are usually recorded include:- The time when trying to fall asleep- The time when sleep onset occurred- The number, time and length of awakenings- The time of waking up- The time of getting upOther inclusions may be naps, alcohol consumption, caffeine,

and use of medication, meal times and exercise.

Characteristics of sleep: The use of EEG, EMG and EOG measures in

human sleep research has lead to a universally agreed classification of sleep into distinct stages.

Stages 1-4 are characterised by different depths of sleep and are known as non- rapid eye movement sleep (NREM).

A 5th stage is characterised by short bursts of rapid eye movements and is know as rapid eye movement sleep (REM sleep)

Characteristics of patterns of sleep Over the course of a typical night’s sleep we

experience two distinctly different states, or types of sleep known as NREM sleep and REM sleep.

These occur in continuous cycles, with one following the other.

In adults one cycle of NREM sleep lasts for about 70-90 minutes, and consists of four distinct stages, each of which can be identified by a different brain wave pattern.

Characteristics of patterns of sleep A period of REM sleep follows each period of NREM

sleep.

Therefore NREM is sometimes referred to as the fifth stage of sleep.

A complete sleep cycle consists of a period of NREM sleep (but not necessarily all four stages) and a period of REM sleep (which tends to increase in duration as the night progresses).

Generally a complete sleep cycle lasts about 80-120 minutes, and we go through this cycle about four or five times during eight hours of sleep.

NREM sleep

Approximately 80% of our sleep time is spent in NREM sleep, and typically the first half of the night has more NREM than the second half.

During NREM sleep the brain is active (but not as active as during REM sleep or NWC).

NREM sleep consists of 4 different stages.

When we first close our eyes and begin to relax our brain emits a burst of alpha waves.

Falling asleep Alpha wave patterns are associated with relaxation and

drowsiness.

They produce a pattern of relatively high frequency and medium amplitude waves.

The transition of being awake to being asleep is known as a hypnogogic state and is characterised by slow rolling eye movements.

During this stage people may experience:- Flashes of light- Feelings of floating or weightlessness - Dreamlike images- Jerky movements

NREM stage 1 Stage 1 occurs when we drift in and out of a true

sleep state.

Physiological changes include:- Decrease in heart rate- Decrease in respiration- Decrease in body temperature- Decrease in muscle tension

A hypnic jerk may be experienced in which the body seems to go into spasm or jerk.

NREM stage 1 The EEG patterns will show a decrease in alpha

waves and these will be replaced by the more irregular theta waves. (Theta waves- mixture of high and low amplitude).

Stage 1 lasts for around 5-10 minutes

If we are woken during this stage, we may feel as if we have not slept at all.

NREM stage 2

Stage 2 is a light stage of sleep.

It lasts for around 10-20 minutes.

Physiological changes:- Body movements lessen- Breathing becomes more regular- Blood pressure and temperature continue to fall- Heart rate is slower

NREM stage 2 Brain waves are mainly theta waves, but slightly lower in

frequency and higher in amplitude than the theta waves produced in stage 1.

During stage 2, brief bursts of higher frequency brain wave activity called sleep spindles periodically appear on the EEG reading.

Sleep spindles last for about 1 second and indicate that the person is truly asleep.

EEG patterns also show bursts of low frequency and high amplitude waves, called k complexes in response to arousing stimuli.

NREM stage 3 Stage 3 is the start of the deepest period of sleep.

Lasts for about 10 minutes

Physiological changes:- Body movements lessen- Breathing continues to be slow and steady- Blood pressure and temperature continue to fall- Heart rate is slower

- The individual is extremely relaxed.

NREM stage 3 In this stage people are difficult to arouse

During stage 3 there is a reduction in the brain’s electrical activity, and delta waves begin to appear in the EEG reading.

The presence of delta waves marks the beginning of slow wave sleep (SWS) so called because of the slower frequency delta waves.

Generally we begin SWS within an hour of falling asleep, and remain in it for around 30 minutes.

NREM stage 4 Stage 4 is the deepest stage of sleep.

Physiological signs:- Muscles are completely relaxed and we barely

move.

Delta waves dominate the EEG patterns and are even slower and larger than in stage 3.

A person in this stage is very difficult to wake.

NREM stage 4 People who wake up in this stage may take up to 10

minutes to orient themselves and may be mentally confused.

Psychologists use the term sleep inertia when referring to this mental lag.

In the first cycle of sleep a person may spend up to 20 minutes in stage 4, however as the night progresses less time is spent in stage 3 and 4. In those cycles close to the morning there may be no time spent in these stages.

NREM stage 4 It is during this stage of sleep that sleep phenomena

such as sleep walking, sleep talking and night terrors may occur.

The progression through NREM sleep from stage 1-4 takes about 45-60 minutes before we progressively move back up through stages 3, 2, and then 1.

REM sleep REM sleep is a period of rapid eye movement sleep

during which the eyeballs rapidly move beneath the closed eyelids.

EEG patterns show irregular waves consisting of low amplitude, relatively high-frequency beta waves like those produced in alert wakefulness.

The body’s internal functioning is more active during REM sleep than during NREM sleep.

REM sleep Physiological changes:- Heart rate is faster and more irregular- Blood pressure rises- Breathing is quicker and more irregular- Most muscles are limp except for the occasional

twitch or jerk

REM sleep is sometimes called paradoxical sleep because internally the brain and body are active but the body appears calm and inactive.

REM sleep One explanation for this paralysis is so that we are

unable to act out our dreams.

It is in REM sleep that most dreaming occurs.

We all dream several times a night even if we do not remember dreaming.

Dreaming also occurs during NREM sleep but the dreams are less frequent, less memorable, less vivid and less fragmented that those of REM sleep.

REM sleep Some suggestions about the reasons for REM

sleep:- REM sleep may assist in consolidating new

memories in the brain- Probably serves an important biological need

Throughout the night we pass continuously through NREM and REM sleep cycles, with REM periods lengthening and occurring closer together as the night progresses.

Sleep patterns summary

Awake EEG: beta waves: high F, low A

NREM Stage 1 (drowsy)EEG: alpha waves: mid-high F, mid-low AEMG: Reduction in muscle tension (but muscles still active)Other sign: hypnic jerk EOG: May be slow, rolling movements

Sleep patterns

NREM Stage 2 (light sleep)EEG: theta waves = low F, mixed A. Sleep spindles (burst of high F)K complexes (burst of high A).EMG: Medium ActivityEOG: No movement

NREM Stage 3 (sleep)EEG: theta & delta waves = higher A, lower FEMG: Medium or Low ActivityEOG: No movement

Sleep patterns NREM Stage 4 (deep sleep)

EEG: delta waves = high A, low FEMG: Medium or Low ActivityEOG: No movement

REM (Rapid Eye Movement)EEG: Beta waves: irregular bursts of high F, low AEMG: Low Activity (temporary paralysis)EOG: Sharp, intermittent eye movements

REM NREMCataplexy: muscles relax to near paralysis

Individual can still move

Eyes move rapidly Eyes don’t move

Most dreaming occurs Some dreams

Purpose:Consolidation of LTM

Purpose:Physical growth and body repair

~20% of adult’s sleep ~80% of adult’s sleep

Typical Sleep Pattern

Sleep cycles of 90mins through night.

NREM stage 1 to 4, then back, then REM.

More time in NREM at start of night

More time in REM later in night

CHANGES IN SLEEP PATTERNS OVER THE

LIFESPAN The amount of time spent in each stage is highly variable.

Eg. Poor sleepers are likely to spend less time in stage 4 and REM sleep.

The amount spent in each stage also changes across the lifespan.

Eg. A newborn infant sleeps for around 16 hours a day and around 50% of that is REM sleep.

By the end of infancy, total sleep time drops to around 12-13 hours and about 25-30% is REM sleep.

By the end of childhood and onset of adolescence, total sleep time drops to around 9 hours and about two hours or 20% is REM sleep.

By late adulthood, the total sleep time averages six to seven hours, with about one third in REM sleep.

People in their sixties and older tend to report that their sleep is much lighter with increased awakenings than when they were younger.

By age 90, stage 3 and stage 4 is rarely experienced, if at all.

Negative correlation between age and hours of sleep.

Negative correlation between age and REM sleep.

Sleep-wake cycle shift during adolescence

In general adolescents tend to lesson the hours they sleep each night from 10 to less than 8 between the ages of 13-19.

Studies have found however, that adolescents require more than 9 hours sleep a night to function well when asleep.

They also seem to have a higher percentage of sleep problems like:

- Taking a long time to fall asleep- Insufficient night time sleep- Difficulty waking in the morning

This can lead to difficulties in daytime functioning like:

- Difficulty concentrating in class- Mentally ‘drifting off’ or falling asleep in class- Lethargy- Problems staying motivated.

Each day our body goes through a cycle called a circadian rhythm during which hormones are produced to control bodily functions.

Melatonin is one of these hormones and this causes us to feel sleepy at night.

The cycle is also linked to external cues like sunlight, alarm clocks, meal times and even television.

During adolescence there is a hormonally induced shift of the body clock about two hours, making the adolescent sleepier one or two hours later.

This is known as the sleep-wake cycle shift and this affects their ability to fall asleep at the earlier time that they would of as a child.

This also means that they have the biological need to sleep a couple of hours longer in the morning.

For teenagers, this is virtually impossible given their school and work schedules.

As a results this nightly sleep loss can accumulate as a sleep debt; that is, sleep that is owed and needs to be made up.

Eg. A nightly sleep debt of 90 minutes between Monday and Friday would add up to a total sleep debt of seven and a half hours.

Often on the weekends teenagers would sleep for longer to make up for this debt which can also be problematic.

THE PURPOSE OF SLEEP

Research investigated on the effects of sleep deprivation and the amount of sleep has lead to a number of theories that provide answers about WHY we need to sleep.

Most theories however, can provide some explanation for the reasons why sleep is such a necessity.

Restoration Restorative theories propose that sleep provides

‘time out’ to help us recover from depleting activities during waking time that use up the body’s physical and mental resources.

- Allows us to replenish the energy used up during the day

- Allows damaged cells to be repaired- Allows muscles to be detoxified and rid themselves of

waste products This is supported by our view that we feel tired before

we go to sleep and replenished when we wake up in the morning.

Evidence Study 1: When we are asleep our physiological

functions slow down and growth hormone which promotes body repair is secreted at a much higher level than when awake.

Study 2: Athletes who competed in a 92km marathon found that when allowed to sleep as long as they wanted to they slept significantly longer and deeper in the following two nights after the race.

Study 3: Experiments with rats have found that prolonged sleep deprivation results in the breakdown of various bodily tissues and death within three weeks.

Restoration

NREM sleep is believed to be important for repairing and restoring the body whereas REM sleep is believed to restore the brain and may have a role in higher mental functions like memory and learning.

NREM REM-Physical growth, tissue repair and recovery from the effects of fatigue occur during stages 3 and 4 of NREM sleep.

-Brain growth and restoration occur during REM sleep. -REM is a lot more predominant in infants than in later years indicating that REM sleep plays an important role in brain development in the early years.

Restoration Psychologists generally believe that REM sleep

has some biological quality that we need. When lab patients are woken each time they

enter REM sleep they do not seem to show any adverse signs, however, when left to rest normally they will spend more time in REM sleep than usual. This indicates that there is a need for them to ‘catch up’ on lost REM sleep.

This is called REM rebound which involves catching up on REM sleep immediately following a period of lost REM sleep when next asleep.

SURVIVAL

The survival theory of sleep proposes that sleep evolved to enhance survival by protecting an organism through making it inactive during the part of the day when it is most risky or dangerous to move about.

Sleep serves the function of protecting the sleeper from harm or death, and therefore enhances survival of the species.

Evidence Animals with few natural predators, such as lions,

tigers and gorillas, sleep as much as 15 hours a day.

Grazing animals like horses, zebras and cows have many predators and would struggle to escape from them. They cannot hide easily, climb trees or burrow quickly to escape danger and therefore tend to only sleep around 4 hours total in the day.

Smaller animals like bats and possums eat less food and take less time to digest it as well as usually sleeping in safe places. This means they do not need to spend much time awake.

Evidence

Humans sleep at night because we are highly visual creatures who need light to find food and do other things necessary for survival.

At night it may have been best for us during our evolution to be asleep at night to avoid any dangers.

Criticisms

One criticism is that it does not explain why sleep involves a loss of awareness since the loss of consciousness during sleep may place the organism at greater risk.

There is only limited evidence to support each of these theories.

SLEEP DEPRIVATION

Sleep deprivation

The term sleep deprivation means going without sleep.

The extent of discomfort depends on the individual, the amount of sleep lost, and the period of time over which the deprivation occurs.

Sleep deprivation

Research into sleep deprivation has identified different effects for different kinds of sleep loss.

3 categories:1. Total deprivation2. Partial deprivation3. Selective deprivation

We will focus on total deprivation and partial deprivation.

Sleep deprivation Unethical to conduct research on humans so most

total deprivation research has been conducted on animals.

Rats have been the main participants.

The sleep deprived rats typically were unable to maintain a constant body temperature, resulting in excessive heat loss.

They eventually died after 2-3 weeks.

Sleep deprivation Autopsies show that the rats immune systems had

collapsed, resulting in blood poisoning and untimely death.

It was then proposed that sleep is vital to the regulation and stability of an animals internal environment and this may also apply to humans.

Research conducted on people that have voluntarily become sleep deprived has found that although there are some serious psychological and physiological effects none of these are permanent.

Sleep Deprivation: partialTirednessLack of energyLapses in attentionInability to concentrate for long periodsLow level of motivationImpaired motor skillsIrritabilityOccasional headachesDecline in ability to perform cognitive tasksSlower reaction times on motor tasksThinking in irrational and illogical waysDifficulty making decisions

Partial sleep deprivation Generally over a short period of time, partial sleep

deprivation has temporary and relatively minor effects. A person can also quickly recover when the sleep debt

is repaid. People, however, underestimate the effects of partial

sleep deprivation over a prolonged period. William Dement (1999) believes that millions of people

throughout the world are ‘living less than an optimal life and functioning at less than optimal level, impaired by an amount of sleep debt that they are not even aware they are carrying’.

He believes that the high level of sleep deprivation in adolescents could even be fatal as they are in a high risk of accident category.

30% of road accidents occur when drivers fall asleep on long boring stretches of road.

After only 4 hours of sleep deprivation, reaction time is as much as 45% lower than usual.

Memory processes may also be impaired.

Total sleep deprivation Studies on the effects of total sleep deprivation

in humans have tended to rely on convenience samples.

In one case of total sleep deprivation, teenager Randy Gardener stayed awake for 264 consecutive hours (11 days) as part of a high school science project.

Although he experienced a range of physiological and psychological effects throughout the experience, he did not experience any long lasting effects.

Some people however, experience more debilitating effects like depression, hallucinations, delusions and paranoia.

In 1959, American DJ Peter Tripp remained awake for 100 hours for charity and began to experience severe psychological disturbances. He claimed to see a rabbit run along the radio booth (hallucination) and cobwebs in his shoes. He had difficulty thinking clearly and remembering things. Eventually he became paranoid believing people were trying to drug him to force him asleep.

He was escorted home after 201 hours without sleep and slept continuously for 13 hours. When he woke he had returned to normal.

Sleep DeprivationPsychological Effects: Impaired cognition due to reduced concentration,

motivation and attention. Increased irritability Ability to perform simple tasks more affected than

performance on complex tasks Moodiness Increased anxiety Impairment of memory processes (STM) Depression Hallucinations, delusions & paranoia

Sleep DeprivationPhysical Effects Sleepiness and fatigue Droopy eye lids Difficulty focusing Slurred speech Increased sensitivity to pain Hand tremors HeadachesAfter 5 consecutive days: The heart and respiratory system become slower Body temperature drops The immune system is lowered making us more vulnerable

to illness

Sleep deprivation After 3-4 sleep-free days we involuntarily drift into

microsleeps

A microsleep is a very short period of drowsiness or sleeping that occurs while the person is apparently awake.

During a microsleep the EEG pattern resembles the early stages of NREM sleep.

During this time the person will have no recollection of the events unfolding.

We do not seem to have to fully compensate for all sleep lost, but we will make up for lost sleep by gaining a few extra hours over the next few nights.

Sleep deprivation vs alcohol

Does fatigue really kill? Yes! 20 hours sleep-free = perform at same level

as with BAC 0.05% 24 hours sleep-free = perform at same level

as with BAC 0.10%