Ch 6 the demand for sleep

Question 1

Psychological construct

Answer 1

an agreed upon description and understanding of psychological phenomena that cannot be overtly measured or observed
subjectively experienced, cannot be measured objectively
physiologicall measured, but cannot be psychological measured?

Question 2

Consciousness

Answer 2

level of awareness an individual has over their thoughts, feelings, perceptions, and existence.
- a psychological construct.

Question 3

Normal waking consciousness (NWC)

Answer 3

is a state of consciousness in which an individual is awake and aware.

Question 4

Altered state of consciousness (ASC)

Answer 4

A state of consciousness that is distinctly different from normal waking consciousness in terms of quality of experience and levels of awareness.

induced and naturally occuring

Question 5

Naturally occurring altered state of consciousness

Answer 5

A type of altered state of consciousness that occurs without intervention.
Eg, sleep, daydreaming

Question 6

Induced altered state of consciousness

Answer 6

A type of altered state of consciousness that occurs due to a purposeful action or aid.

Eg, Meditation, hypnosis, influence of alcohol and/ or drugs

Question 7

Sleep

Answer 7

is a regular and naturally occurring altered state of consciousness that involves a loss of awareness and disengagement with internal and external stimuli. Sleep can also be considered a psychological construct.

Question 8

REM definition

Answer 8

REM (rapid eye movement) sleep is a type
of sleep characterised by rapid eye movement, high levels of brain activity, and low levels of physical activity.

REM sleep involves low levels of somatic nervous system activity, meaning there are low levels of movement in this stage

Question 9

NREM definition

Answer 9

(non-rapid eye movement) sleep is a type of sleep characterised by a lack of rapid eye movement and is subdivided into three different stages.

Question 10

Sleep Episode

Answer 10

full duration of time spent asleep. A sleep episode is made up of multiple repeated cycles of REM and NREM sleep, called sleep cycles.

Question 11

Sleep cycles

Answer 11

an approximately 90-minute-period that repeats during a sleep episode in which an individual progresses through stages of REM and NREM sleep.

Question 12

Characteristics of REM

Answer 12

• sleeper is considered to have a highly active brain and a less active body during REM sleep.
• virtually paralysed during REM sleep, meaning that most muscle movement is not possible.
• relatively light stage of sleep; despite the muscle paralysis, the brain is active and sleepers can be woken fairly easily. (low arousal)
• Vivid dreaming tends to occur during REM sleep. The sleeper frequently recalls dreams when woken during REM sleep.
• REM sleep makes up approximately 20–25% of a sleep episode for most age groups.
  elids, darting back and forth and up and down in jerky but coordinated movements.
• amount of time spent in REM sleep increases as the sleep episode progresses, with the largest amount of REM in the sleep cycle occurring immediately before waking.
• Early in the night, REM sleep may only last a few minutes, but later during the night, it can last up to an hour.
• defined by spontaneous bursts of rapid eye movement, during which the eyeballs quickly move beneath the closed ey

Question 13

Characteristics of NREM

Answer 13

• The sleeper is considered to have a less active brain than normal waking consciousness.
• As opposed to REM sleep, physical movement is possible in NREM sleep, therefore the body is said to be ‘more active’ in this stage of sleep. However, movement tends to decrease as NREM stages progress.
• Dreams can occur in NREM sleep but they are often non-vivid (as opposed to REM sleep).
• The sleeper does not frequently recall dreams when woken during NREM sleep.
• The amount of time spent in NREM sleep is highest during the first half of a sleep episode.
• NREM sleep makes up approximately 75–80% of a sleep episode.
• NREM sleep tends to become shorter with each sleep cycle.
• NREM sleep is subdivided into three stages. These are explored in table 3.

Question 14

NREM Stage 1

Answer 14

• the sleeper transitions from being awake into a light sleep.
• This transition is signified by the experience of the hypnagogic state, in which some people experience feelings of floating or falling, or a sudden jerk (referred to as a hypnic jerk).
• sleeper loses awareness of themselves and their surroundings but is still aware of faint sounds in the environment.
• The sleeper can be easily woken, low arousal threshold. If awoken we may feel, as if we haven’t slept at all.
• Decrease in heart rate, respiration, body temperature and muscle tension.
• amounts to 4-5% of total sleep time
• slow, rolling eye movements are also likely to be observed

Question 15

NREM Stage 2

Answer 15

• relatively light sleep
• individuals spend majority of their time asleep in NREM Stage 2.
• Sleeper is considered ‘truly asleep’ due to brain waves.
• body movements lessen, breathing becomes more regular.
  body temperature falls with minimal eye movements
  N2 is marked by brief bursts of high-frequency called sleep spindles, their presence is used to signal the transition to N2.
• k-complexes: bursts of low frequency, slightly higher amplitude waves in response to stimuli.
• lasts 10-20 minutes.
• N2 has a higher arousal threshold than N1 but we can still be easily aroused from sleep during N2.

Question 16

NREM Stage 3:

Answer 16

• heart rate, blood pressure, body temperature continue to drop and breathing rate continues to be slow and steady.
• deep stage of sleep
• difficult to wake the sleeper in this stage. N3 has the highest arousal threshold.
• sleeper if woken during this stage are likely to feel drowsy and disoriented.
• sleepwalking and sleeptalking are most likely to occur.
• sleep inertia - when woken, may take up to 10 minutes to orient themselves
• As the night progresses, less and less time is spent in N3 deep sleep and it may disappear altogether.
  Makes up 10-15% of total sleep time.

Question 17

Electroencephalograph, electro-myograph and electro-oculargraph are…

Answer 17

considered objective physiological measures. Proves and provides reliable, unbiased, quantitative data that can indicate someone’s state of consciousness.

however changes in physiological responses may be due to factors other than changes in consciousness and thus findings may lack validity at times.

Question 18

Sleep diaries and Video monitoring are…

Answer 18

subjective measures provided by an individual and is related to personal experiences.

Sleep diary is useful to obtain detailed information about an individual’s sleep patterns so that doctors may be able to identify any sleep problemd and provide effective treatment.

However, the accuracy and reliability of these measures may be limited due to subjective nature.

Question 19

Electroencephalograph (EEG)

(frequency + amplitude)

Answer 19

is a device that detects, amplifies and records the electrical activity of the brain.

Frequency is the number of brain waves that occur per second whilst amplitude is the intensity and height of the brain waves.

Question 20

EEG is likely to show

Answer 20

higher frequency and lower amplitude when in NWC and a lower frequency and higher amplitude during ASC.

Therefore:
REM: higher frequency and lower amplitude (beta-like)
NREM 1: high frequency and low amplitude but lower frequency and higher amplitude than NWC (alpha)
NREM 2: medium frequency and amplitude (theta)
NREM 3: lower frequency and higher amplitude (delta)

Question 21

Strength and Limitation of EEG

Answer 21

Strength: Measure that is useful for sleep studies or diagnoses of patients with brain damage, mental/neurological disorders.

Limitations: as a measure of sleep that it measures neural activity underneath a thick and hard skull and is not entirely precise.
Does not identify functional/dysfunctional areas of the brain as well as neuroimaging techniques.
cannot show structure of the brain

Question 22

Electromyograph

Answer 22

is a device that detects, amplifies and records the electrical activity of the body’s muscles.

• muscles movement and tension can be used to identify the different stages and types of sleep an individual may be experiencing through gathering information of how active a person’s muscles are.

REM = low activity
NREM = medium/moderate activity –> as NREM stage progresses, EMG shows lower activity as movement is less likely to occur.

Question 23

Electro-oculograph

Answer 23

is a device that detects, amplifies and records the electrical activity of the muscles responsible for eye movement.

Eye movements, facilitated by movements of muscles surrounding the eyes are a physiological response used to investigate the type of sleep a person is experiencing.

EOG measurement:
REM: high activity
NREM: low activity

Question 24

Sleep diaries

Answer 24

are a record containing self-reported descriptions from an individual about their sleeping periods, including an estimated time spent sleeping and judgements they might have about the quality and nature of their sleep.

Question 25

Sleep diaries data

Answer 25

Includes both qualitative and quantitative information.
Subjective and less reliable than objective measures.
Beneficial as provides qualitative information that is extensive in detail and description of an individuals sleeping patterns.
However, they are interpreted by a doctor which leaves room for error and innacuracy.

Question 26

What’s included in a sleep diary?

Answer 26

duration of sleep
quality of sleep
thoughts and feelings before going to sleep and waking up
behaviours before going to sleep and after waking up
number of times sleep was disrupted.

Question 27

Video monitoring

Answer 27

involves the use of camera and video technologies to record an individual as they sleep. This provides data specific to the individual to track their sleeping and walking periods, movements and activities when sleeping and the sounds they make while sleeping.

involves the use of camera and video technologies to record specific data of an individual as they sleep, tracks sleeping/walking periods, movements and sounds

Question 28

Biological Rhythms

Answer 28

are repeated biological processes that are regulated by internal mechanisms.

Question 29

Circadian Rhythms

Answer 29

are biological and behavioural changes that occur as part of a cycle that lasts around 24 hours.

Sleep-wake cycle is a type of circadian rhythm.
(body clock)

Question 30

Ultradian Rhythms

Answer 30

are biological and behavioural changes that occur in a cycle that lasts less than 24 hours.
- a sleep cycle is therefore an example of an ultradian rhythm.

Question 31

Suprachiasmatic Nucleus

Answer 31

The suprachiasmatic nucleus is an area of the hypothalamus that is responsible for regulating an individual’s sleep-wake pattern by acting like an internal body clock.

Question 32

How does the SCN regulate the sleep-wake cycle?

Answer 32

1) Receives external and internal cues
2) After receiving both cues, the SCN sends neural messages (signals) to the pineal gland to produce and release melatonin
3) The pineal gland releases melatonin into the bloodstream, which promotes feelings of calm and relaxation thus promoting sleep

Question 33

External Cues
Internal Cues

Answer 33

External: involves info from the environment like the presence or absence of light.
Internal: involve info that originates within the body

Question 34

Pineal Gland

Answer 34

which is a gland in the brain responsible for the production and release of melatonin

Question 35

Melatonin

Answer 35

is a hormone released by the pineal gland typically at night-time to induce sleep as a part of the sleep-wake cycle.
The body produces melatonin naturally and usually in adequate amounts.
does not directly induce sleep, but rather promotes a state of calm and relaxation to help make it easier to fall asleep.

Question 36

SCN role in melatonin release

Answer 36

1. The SCN receives external cues. The SCN also receives internal cues.
2. After receiving both internal and external cues, the SCN sends neural messages (signals) to the pineal gland to produce and release melatonin.
3. The pineal gland releases melatonin into the bloodstream, which promotes feelings of calm and relaxation, therefore promoting sleep.

Question 37

Cortisol

Answer 37

Cortisol is a hormone that is responsible for increasing alertness and maintaining heightened arousal.
Released by the adrenal glands in the morning to promote wakefulness and alertness.
The SCN is not responsible for releasing cortisol, but rather, the adrenal cortex is.

Question 38

Neonatal period (1–15 days)

Answer 38

During this period, sleep duration is the highest it will ever be in the lifespan. New-born babies sleep for approximately 16 hours.
* Approximately 50% REM sleep and 50%NREM.

Time spent in REM sleep is significantly high because newborns and infants are experiencing rapid brain development.

Sleep onset may occur at anytime of the day or night with no regular rhythm of sleeping and waking periods, sleep duration also tends to be irregular.

Sleep onset occurs through REM sleep, not NREM Stage 1, believed to occur primarily because circadian rhythms are not fully developed and synchronised with daily day and night cycle of their external environment.

Question 39

Infancy (3–24 months)

Answer 39

Sleep duration decreases to approximately 13.5 hours.
* The proportion of REM and NREM sleep also changes to approximately 35% REM sleep and 65% NREM sleep.

When 3 months of age, NREM-REM cycles become regular and sleep onset begins with NREM stage 1.

Question 40

Childhood (2–14 years)

Answer 40

Sleep duration decreases again to approximately 11 hours.
The proportion of NREM sleep increases slightly to around 80%, while REM sleep decreases to approx 20% of the sleep episode.

Time spent in REM sleep starts to reduce as the pace of brain development steadies.

Sleep duration starts at around 12 hours when children are about two years old, and decreases to around 10 hours when children are about 14 years old. REM sleep also starts at around 25% of the sleep episode and decreases to around 18.5% of the sleep episode.

Question 41

Adolescence (14–18 years)

Answer 41

Sleep duration decreases again to approximately 9 hours.
* constant at 20% REM and 80% NREM sleep.
* Adolescents also experience a biological delayed sleep onset by 1–2 hours, meaning they are more likely to become sleepier later and wake up later.

Sleep patterns can change due to various social factors that play a role in the decreased proportion of sleep , such as having to wake up early for school and having social commitments during the nighttime. Adolescents are also more prone to delayed circadian phase disorders in which their biological ‘clocks’ are not in alignment with the demands of their environments.

Question 42

Young adulthood (18–30 years)

Answer 42

Sleep duration decreases again to approximately 7.75 hours.
* The proportion of REM and NREM sleep remains fairly constant at 20% REM and 80% NREM sleep.

Question 43

Middle adulthood (30–75 years)

Answer 43

Sleep duration remains at approximately 7–8 hours.
* The proportion of REM and NREM sleep remains fairly constant at 20% REM and 80% NREM sleep.

In older adults, lower levels of sleep tend to be attributed to ill-health and an increase in the prevalence of sleep disorders, as well as the reduced amount of cognitive and physical growth within this age group.

Question 44

Old age (75+ years)

Answer 44

Sleep duration continues to decrease to approximately 6 hours.
* fairly constant at 20% REM and 80% NREM sleep.
* Older adults tend to experience advanced sleep phase syndrome, which is a biological shift forward in their sleep-wake cycle, meaning they become sleepier earlier and wake up earlier.

• 60+ Research findings suggest that NREM sleep of elderly people is mostly stage 2 light sleep. Sleep is much lighter with increased awakenings due to decline in NREM stage 3 sleep with age.

Question 45

Neonatal period sleep requirement and average

Answer 45

sleep requirement: 14-17 hours
average: 16-18

Question 46

Infancy (3–24 months) sleep requirement and average

Answer 46

sleep requirement: 12-15 hours
average: 13-15

Question 47

Childhood (2–14 years) sleep requirement and average

Answer 47

sleep requirement: 10-14 hours
average: 11

Question 48

Adolescence (14–18 years) sleep requirement and average

Answer 48

sleep requirement: 8-10 hours
average: 9

Question 49

Young adulthood (18–30 years) sleep requirement and average

Answer 49

sleep requirement: 7-9 hours
average: 7.75

Question 50

Middle adulthood (30–75 years) sleep requirement and average

Answer 50

sleep requirement: 7-9 hours
average: 7-8

Question 51

Old age (75+ years) sleep requirement and average

Answer 51

sleep requirement: 7-8 hours
average: 6

Question 52

sleep-wake cycle

Answer 52

a 24-hour-cycle that is made up of time spent sleeping and time spent awake and alert

Question 53

EOG Measurement for REM

Answer 53

Defined by spontaneous bursts of rapid eye movement during which the eyeballs move quickly beneath closed eyelids.

Question 54

Sleep inertia

Answer 54

Sleep inertia (aka ‘sleep drunkenness’): when woken, may take up to 10 mins to orient themselves & usually have poor memory of sleep events.

Question 55

Sleep onset/ Sleep latency

Answer 55

The transition period from being awake to being asleep is usually called sleep onset and the amount of time it takes to fall asleep once the attempt to do so is made is called sleep latency.

Question 56

Dreams REM

Answer 56

Vivid
sleeper can frequently remember

Many of our dream storylines are similar to concerns we have in everyday life and incorporate experiences from the previous day/week.

Typical REM dreams have a narrative structure and consist of storylines that can range from realistic to complete fantasy.

Question 57

Dreams NREM

Answer 57

Non-vivid.

Dreaming can occur in NREM but is less frequent
(approximately 10%) and harder to remember than
dreams that occur in REM.

NREM dreams tend to be similar to waking thought
patterns; they are usually shorter than REM dreams, less intense and without a real storyline.

People who are light sleepers or anxious are more likely to dream in NREM.

Question 58

Biological clock

Answer 58

Each biological rhythm is maintained and controlled by a biological clock. A biological clock is an innate timing mechanism that regulates the cycle of a biological rhythm.

Question 59

REM is important for

Answer 59

REM sleep has been suggested to be important for the brain and cognitive development and rest. (restorative theory)

Question 60

NREM sleep is important for

Answer 60

NREM sleep has been suggested to be important for physiological rest and development.

Theory: NREM sleep may be the time when the body recovers, repairing body tissue, removing waste products & replenishing neurotransmitters. (restorative theory)

Question 61

Why does an individual’s sleep requirements change?

Answer 61

An individual’s sleep requirements change because their physical and cognitive needs change over time.

Question 62

Loss of NREM in Middle-Aged adults

Answer 62

There is a gradual loss of NREM stage 3 sleep.
By age 60 or so, a severe reduction is evident. People at age 60 may spend only about half as much time in NREM stage 3 as they did at age 20.
Eventually stage 3 disappears altogether.

Sleep also tends to become more fragmented as we age, with more night-time awakenings among older adults. One reason for more frequent awakenings is the decline in NREM stage 3 sleep with age as we are harder to wake in stage 3.