Sleep

CH 6 & 7

Sleep

• Psychological construct

• naturally occurring altered state of consciousness

• REM & NREM sleep

Consciousness

• awareness of the world (internal & external stimuli)

• Normal waking consciousness

• Altered state of consciousness

  • naturally occurring (sleep)

  • Induced

Consciousness continuim

* progression of states of consciousness ranging from least to most aware
* Least aware
* altered state of consciousness (coma, alcohol induced, sleep, daydreaming)
* normal waking consciousness (relaxed, focused)
* Most aware

Physiological measures

• objective

• D.A.R.E

  • detect, amplify, record, electrical activity in…

• EEG - brain

• EMG - muscles

• EOG - muscles surrounding eye

EEG

• electrodes placed at points on surface of scalp

• records patterns of electrical impulses produced by neurons in the brain

EOG

* electrodes attached to upper face
* above one eye & side of each eye near temple

EMG

electrodes attached to the jaw or lower face

EEG brain wave patterns

Beta

• high frequency, low amplitude

Alpha

• High frequency (< beta), Low amplitude (> beta)

Theta

• Medium frequency, mixed amplitude (high & low waves)

Delta

• Low frequency, high amplitude

Subjective reporting

• obtain data directly from individual

• often self-report/observation

• considered biased

Sleep diaries

• record containing qualitative description of amount & nature of sleep over a period of time

Video monitoring

• Involving video & sound recordings of an individual in their sleeping period

• done in sleep lab

Biological rhythms

• sleep follows a naturally occurring biological rhythm

• Rhythms are controlled by our inbuilt ‘biological clocks’ in the brain

  • influenced by external environmental factors

• Circadian

• Ultradian

Circadian rhythm

• follows a 24h cycle of change to physiological functioning & activity

Sleep-wake cycle

• daily cycle of being awake & alert and time spent sleeping

Suprachiasmatic nucleus (SCN)

• inbuilt biological clock

• monitors external light levels to control related activities of sleep wake cycle (circadian rhythm)

• detect light and signals pineal gland to vary how much melatonin(feel drowsy) should be released

Ultradian rhythm

• follows a cycle of less than 24h’s

e.g. eye blinks, heart beats, sleep patterns

• move between REM & NREN=M sleep in cycles

  • 90 min long, 4-5 cycles per night

Sleep cycle

• REM (vivid dreaming)

• N1

• N2 (Light sleep)

• N3 (deep sleep)

Hypnogram

* sleep graph that shows the timing of ultradian sleep cycles (REM & NREM) over the sleep period

NREM

• stages of sleep not associated with rapid eye movement

• contains little dreaming

• individual can move

• body temp falls

• brain waves are slow and rhythmic

• several stages

REM

• begins about 90 min after we fall asleep

• rapid eye movement

• inhibition of voluntary muscles despite electrical brain activity being similar to waking state

Sleep across the lifespan

Amount of sleep decreases with age (NREM increases, REM decreases)

Newborn:

• 14-17h

• 50/50% NREM & REM

Child:

• 10-12h

• 75/25% NREM & REM

Adolescent:

• 9h

• 80/20% NREM & REM

Adult:

• 7-8h

• 80/20% NREM(less in deep sleep) & REM

Elderly:

• 6-7h

• 80/20% NREM(less if any in deep) & REM

Sleep deprivation

occurs through lack of sleep

total/fill:

• no sleep within 24h period

Partial:

• some sleep within 24h but not enough or poor quality

Effects of sleep deprivation

Affective:

• difficulty judging others emotions

• irritability

• mood swings

Behavioral:

• lack of energy

• increased likelihood of risk taking

• lapses into microsleeps

Cognitive:

• impaired decision making

• lapses in attention

• harder to perform tasks

Physiological:

• headaches

• dizzy

• shaky hands

Psychological:

• confusion

• difficulty to concentrate

• difficulty to process information

BAC

alcohol = depressant

slow down nervous system

decrease alertness, decision making and reflexes

• (partial) 17h sleep dep = 0.05 BAC

• (total) 24h sleep dep = 0.10 BAC

Affective effects:

• happy, excited, angry, sad

Cognitive:

• slower mental processes

• decreased ability to reason & problem solve

Delayed sleep phase syndrome (DSPS)

delay(2-3h) in sleep onset resulting in going to sleep later and wanting to wake up later

• common in adolescents(7-16%)

Symptoms:

• excessive sleepiness

• difficult to wake at normal time

Causes:

• Internal biological - puberty, hormones

• internal psychological - rumination

• external - social (work, study, gaming)

Advanced sleep phase disorder (ASPD)

early(2-3h) sleep onset resulting in going to sleep earlier and waking up earlier

• common in older people (1% of elderly)

Symptoms:

• extreme tiredness in evening

• wake early

• tired during day

Causes:

• age related deterioration of biological clock

• decreased exposure to light in arvo/evening

Shift work

employment outside of normal 9-5 work day

• forced to stay awake when circadian rhythm dictates they should be sleeping

• lower quality & quantity of sleep (fragmented)

Impacts:

• sleepiness while working (safety concern)

• insomnia when trying to sleep

• sleep deprivation

• increased risk of mental health problems and physical illness.

Bright light therapy

exposure to intense but safe amounts of light at regular patterns to shift individual’s sleep wake cycle to desired schedule

• light is transmitted to SCN, which then decreases melatonin and increases cortisol levels

must occur at right time to make person feel awake at right time

• DSPS - early in day (up early)

• ASPD - early evening (awake later)

Sleep hygiene

practises & habits that promote an individuals sleep patterns

Effectors (good. vice versa for bad):

• time (consistent)

• sound (quiet)

• light (dark)

• technology/devices (no use before bed)

• associations (only use bed for sleep)

• food/drink consumption (none 2h before)

• exercise (none 2h before bed)

• routine (calm, soothing)

• naps (none)

• environment (cold)

Zeitgebers

external environmental time cues that provide signals to the brain (SCN) to regulate body’s circadian rhythms.

• light

• eating/drinking patterns

• temperature

• alarms, school timetables, bedtime routine

Bluelight:

• type of light

• natural source - daylight

• artificial source - technological devices (phone, laptop)