Week 3: Sleep
, ARTICLES (first brief summary then article notes)
______________________________________________________________________
Chapter 2: normal human sleep: an overview
Carskadon & Dement
ARTICLE SUMMARY
Background To understand sleep disorders we can compare them to normative
patterns
Aim Major sleep disorders discussed and compared to typical sleep pattern
Method Literature review
Main findings We alternate between NREM and REM, newborns have shorter sleep
cycles, NREM waves begin at 2yrs old, SWS gradually decrease as
we age. Discusses also different sensory modalities & role in sleep
Conclusions ^
Keywords REM, NREM, SWS, Sleep disorders, Sleep onset
Abstract
REM /NREM
Typical night sleep pattern begins in NREM and progresses through deeper NREM, before first REM
episode occurs- about 80-100 minutes in
New born enter REM sleep before NREM and have shorter sleep cycles
NREM slow waves are not present til around 2years
Slow sleep waves gradually decreases as we age
This chapter: the typical young adult sleeping pattern is described as a template, several major sleep
disorders are highlighted by their differences from the normative pattern
Sleep definitions
,Sleep is a reversible behavioral state of perceptual disengagement and unresponsiveness
Sleep onset
● Normally onset of sleep is reached through NREM
● Abnormal entry to sleep through REM can be a sign of adult narcolepsy
Definition of sleep onset
● Topic of debate as it is hard to pinpoint
● To understand this better, we look at three basic polysomnographic measures
Electromyogram
Shows a gradual diminution of muscle tonus as sleep approaches but very rarely can pinpoint sleep
onset
Pre sleep level of EEG, especially if person is relaxed, is not distinguishable from normal sleep
Electrooculogram
EOG shows slow possibly asynchronous eye movements that usually disappear within several minutes
Subjects report often report they are still awake during this
Electroencephalogram
Seconds after start of slow eye movements the EEG changes from a pattern of clear rhythmic alpha
activity to low voltage
Sleep onset does not occur all at once often, there can be wavering patterns
Some researchers require presence of K complex and sleep spindles to define sleep onset
, Consensus is that the EEG change to stage 1 usually heralded / accompanied by slow eye movement
identifies the transition to sleep
Behavioral concomitants (accompaniments) of sleep onset
Closer look at behavioral correlates of the wake to sleep transition
Simple behavioural task
When subjects were asked to tap two switches alternately at a steady pace, the behavior continued
after onset of slow eye movements
Simple behaviour can persist past sleep onset and as one passes in and out of sleep, for example could
explain how drowsy drivers can keep going
Visual response
An example of perceptual disengagement from the environment
● In a study subjects were shows a bright light in front of their eyes, when in EEG stage 2 /3 85%
time they say they didn’t see it.
Auditory response
● Examined with series of tones played through earphones, person is meant to report when they
hear a tone, reaction times longer in proximity to the onset of stage 1 sleep
Olfactory response
● Response depends on when it happens in the sleep cycle and what is being smelled
● Mint and strong unpleasant chemical were well maintained during stage 1 sleep
● Olfactory system is not very active and protective during sleep
Response to meaningful stimuli
● Sensory processing to some extent does continue after onset of sleep
● Meaningful stimuli prove that the mind is not impenetrable
, ARTICLES (first brief summary then article notes)
______________________________________________________________________
Chapter 2: normal human sleep: an overview
Carskadon & Dement
ARTICLE SUMMARY
Background To understand sleep disorders we can compare them to normative
patterns
Aim Major sleep disorders discussed and compared to typical sleep pattern
Method Literature review
Main findings We alternate between NREM and REM, newborns have shorter sleep
cycles, NREM waves begin at 2yrs old, SWS gradually decrease as
we age. Discusses also different sensory modalities & role in sleep
Conclusions ^
Keywords REM, NREM, SWS, Sleep disorders, Sleep onset
Abstract
REM /NREM
Typical night sleep pattern begins in NREM and progresses through deeper NREM, before first REM
episode occurs- about 80-100 minutes in
New born enter REM sleep before NREM and have shorter sleep cycles
NREM slow waves are not present til around 2years
Slow sleep waves gradually decreases as we age
This chapter: the typical young adult sleeping pattern is described as a template, several major sleep
disorders are highlighted by their differences from the normative pattern
Sleep definitions
,Sleep is a reversible behavioral state of perceptual disengagement and unresponsiveness
Sleep onset
● Normally onset of sleep is reached through NREM
● Abnormal entry to sleep through REM can be a sign of adult narcolepsy
Definition of sleep onset
● Topic of debate as it is hard to pinpoint
● To understand this better, we look at three basic polysomnographic measures
Electromyogram
Shows a gradual diminution of muscle tonus as sleep approaches but very rarely can pinpoint sleep
onset
Pre sleep level of EEG, especially if person is relaxed, is not distinguishable from normal sleep
Electrooculogram
EOG shows slow possibly asynchronous eye movements that usually disappear within several minutes
Subjects report often report they are still awake during this
Electroencephalogram
Seconds after start of slow eye movements the EEG changes from a pattern of clear rhythmic alpha
activity to low voltage
Sleep onset does not occur all at once often, there can be wavering patterns
Some researchers require presence of K complex and sleep spindles to define sleep onset
, Consensus is that the EEG change to stage 1 usually heralded / accompanied by slow eye movement
identifies the transition to sleep
Behavioral concomitants (accompaniments) of sleep onset
Closer look at behavioral correlates of the wake to sleep transition
Simple behavioural task
When subjects were asked to tap two switches alternately at a steady pace, the behavior continued
after onset of slow eye movements
Simple behaviour can persist past sleep onset and as one passes in and out of sleep, for example could
explain how drowsy drivers can keep going
Visual response
An example of perceptual disengagement from the environment
● In a study subjects were shows a bright light in front of their eyes, when in EEG stage 2 /3 85%
time they say they didn’t see it.
Auditory response
● Examined with series of tones played through earphones, person is meant to report when they
hear a tone, reaction times longer in proximity to the onset of stage 1 sleep
Olfactory response
● Response depends on when it happens in the sleep cycle and what is being smelled
● Mint and strong unpleasant chemical were well maintained during stage 1 sleep
● Olfactory system is not very active and protective during sleep
Response to meaningful stimuli
● Sensory processing to some extent does continue after onset of sleep
● Meaningful stimuli prove that the mind is not impenetrable
