Sleep

• Consciousness

  Our awareness of our thoughts, feelings and perceptions (internal events) and our surroundings (external events)
• Altered states of consciousness

  Any state of consciousness that is distinctly different from normal waking conscious in terms of

  • Level of awareness
  • quality or intensity of perceptions, thoughts, feelings and memory
• Characteristics of ASC

  • memory difficulties and reduced cognitive ability
  • difficulty paying attention to specific tasks
  • changes to levels of awareness (generally lower)
• Sleep


  A reversible naturally occurring altered state of consciousness
• Sleep - over the night 5 sleep cycles approx. 90 minutes each
• Two types of sleep

  1. Non - rapid eye movement
  2. Rapid eye movement
• REM

  Paradoxical sleep - brain is active but physically body is calm
• REM

  • 20 - 25% of sleep time
  • replenishes mind
  • body is completely still
  • REM period lengthened as night goes on
• NREM

  • 75 - 80% of sleep time
  • replenishes body
• NREM

  Stage 1. light sleep or hypnogogic state

  Transition between sleep and awake

  • easily awoken
  • lasts 2 - 10 mins
  • 4 - 5% of total sleep time
• NREM

  Stage 2. light or moderate state

  Truly asleep

  • lasts around 10 - 25 min in first sleep cycle
  • lengthens to 20 - 30 min
  • 45 - 55% of total sleep time
• NREM

  Stage 3. Deep or slow wave sleep

  • if awoken confused
  • lasts 20 - 40 mins, decrease in length as night progresses
  • sleep disturbances (sleeping walking, night terrors) occur in this stage
• Sleep cycles represented on a hypnogram
• NREM

  Stage 1. light sleep or hypnogogic state

  Hypnic jerk: common experience - spasm of a part of our body
• EEG - brain waves

  detects amplifies and records electrical activity of brain waves
• EMG - muscles

  detects amplifies and records electrical activity of the muscles
• EOG - eye movements

  detects amplifies and records electrical activity of the muscles that control eye movements
• EEG

  Low amplitude high frequency - REM sleep
• EEG

  High amplitude low frequency - NREM stage 3
• EOG

  Bursts of rapid eye movement - REM
• EOG

  Little eye movement - drowsy/relaxed
• EOG

  None or very little - NREM
• EMG

  Virtually non existent muscle movement - REM
• EMG

  moderate to low - NREM
• Sleep diary

  Log over-time that provides information regarding lifestyle habits and sleep experience from individuals perspective
• Video monitering

  Using camera to video record a person while sleeping so observable disturbances can be analysed
• Circadian rhythm

  Biological processes that follow a 24 hour period (sleep-wake cycle)
• Zeitgeber

  Environmental cues that influence circadian rhythms

  • light
  • temperature
  • noise
• No light - SCN - pineal gland - releases melatonin
• Ultradian rhythm

  Biological rhythm that follows a cycle less than 24 hours (sleep cycle)
• Newborns - 16 hours

  50% REM, 50% NREM
• Infants 12 - 15 hours

  35% REM, 65% NREM
• Child 9 - 11 hours

  20 - 25%, REM 75-80% NREM
• Adolescent 8 - 10

  20 - 25%, REM 75-80% NREM
• Adult 7 - 9 hours

  20% REM, 80% NREM
• Elderly 6 - 8 hours

  20% REM, 80% NREM
• During adolescent melatonin release is delayed - adolescent goes to bed 1 - 2 hours later and wakes up 1 -2 hours later
• Partial sleep deprivation

  Some sleep in a 24 hour period but less than normally required
• Partial sleep deprivation

  Can occur because:

  • Reduced total sleep time (decrease quality)
  • Disruption in normal progression/fragmented sleep (decreased quantity)
• Partial sleep deprivation - don't need to compensate for amount of sleep lost, few hours of extra sleep over next few nights