measuring sleep

How can sleep be investigated and measured

• By investigating and measuring consciousness through physiological responses or behaviour, since states of consciousness cannot be directly observed

Why can't states of consciousness be directly measured

• Because they are internal and must be inferred from physiological responses or behaviour

What are two main types of data used to study sleep

• Objective physiological changes and qualitative information about changes during sleep

What are some measures used to investigate consciousness and sleep

• Electroencephalograph (EEG)

• Electromyograph (EMG)

• Electro-oculograph (EOG)

• Sleep diaries

• Video monitoring

What does the EEG measure in relation to sleep

• Electrical activity in the brain

What does the EMG measure in relation to sleep

• Muscle activity or tension

What does the EOG measure in relation to sleep

• Eye movements

What is the purpose of a sleep diary

• To record qualitative, self-reported information about sleep patterns and experiences

What does video monitoring provide in sleep studies

• Observational data on sleep behaviours and movements

What does an electroencephalograph (EEG) do

• It detects, amplifies, and records the electrical activity of the brain

What causes the electrical activity detected by an EEG

• Electrical impulses emitted by neurons when they communicate

How is brain activity displayed by an EEG

• As brain wave patterns

How can brain waves help assess a person's state of consciousness

• Different brain wave patterns correlate to different states of consciousness.

What device records brain wave patterns to identify sleep stages

• The electroencephalograph (EEG)

What two key features of brain waves are used to distinguish between states of consciousness

• Frequency and amplitude

What is brain wave frequency

• The number of brain waves that occur per second

What is brain wave amplitude

• The intensity and height of the brain waves

What is the amplitude and frequency of brain waves during normal waking consciousness

• what brain wave and diagram of EEG recording

• Low amplitude and high frequency

What does high frequency and low amplitude brain activity indicate

• Normal waking consciousness or REM sleep (an altered state of consciousness)

What brain wave characteristics are associated with a deeply relaxed or meditative state

• what brain wave and diagram of EEG recording

• Low–medium amplitude and medium–high frequency

What type of brain wave pattern is typically seen in early or light sleep

• what brain wave and diagram of EEG recording

• Medium–high amplitude and low–medium frequency

What are the EEG characteristics of deep sleep

• what brain wave and diagram of EEG recording

• High amplitude (highest of all) and low frequency (lowest of all)

How do EEG wave characteristics change from being awake to deep sleep

• Frequency decreases and amplitude increases

What does an electromyograph (EMG) do

• It detects, amplifies, and records the electrical activity of the body’s muscles

How is muscle activity recorded using an EMG

• Electrodes are attached to the skin above the muscles under investigation

What does an EMG reading show during REM sleep

• Low muscle activity due to low physiological activity

What does an EMG reading show during NREM sleep

• Medium to moderate muscle activity due to some physiological activity

How do EMG readings change as NREM sleep stages progress

• Muscle activity tends to decrease as movement becomes less likely, though it can still occur

What does an electro-oculograph (EOG) do

• It detects, amplifies, and records the electrical activity of the muscles responsible for eye movement

How does an EOG measure eye movement

• By using electrodes attached to the skin above the eye muscles

What do EOG readings show during REM sleep

• High activity due to rapid eye movement

What do EOG readings show during NREM sleep

• Low activity, as there is no rapid eye movement

What are the EEG characteristics of REM sleep

• diagram of brain activity

• High frequency, low amplitude

During REM sleep, what is the level of muscle (EMG) and eye (EOG) activity

• diagram of brain activity

• EMG: No–low activity (lowest)

• EOG: High activity

What are the EEG characteristics of NREM Stage 1

• diagram of brain activity

• Medium frequency

• Medium amplitude

Which stage of sleep has the highest muscle (EMG) activity

• diagram of brain activity

• NREM Stage 1 (medium/moderate activity)

What are the EEG characteristics of NREM Stage 2

• diagram of brain activity

• Medium-low frequency

• Medium-high amplitude

What is the level of eye movement (EOG) in NREM Stage 2

• diagram of brain activity

• Medium-low activity

What are the EEG characteristics of NREM Stage 3

• diagram of brain activity

• Low frequency

• High amplitude

What is the level of EMG and EOG activity during NREM Stage 3

• diagram of brain activity

• EMG: Low activity

• EOG: Low activity

Which sleep stage is associated with high eye activity but minimal muscle tone

• REM sleep

What is a key strength of objective sleep measures like EEG, EMG, and EOG

• They provide reliable, unbiased, quantitative data that can indicate a person’s state of consciousness

What is a limitation of objective sleep measures like EEG, EMG, and EOG

• They do not provide qualitative detail about the personal experience of sleep

Why might findings from EEG, EMG, or EOG sometimes lack validity

• Because changes in physiological responses may be due to factors other than a change in consciousness

What is a sleep diary

• A self-reported record of an individual’s sleep, including estimated sleep time and judgments about the quality and nature of their sleep

What types of data can a sleep diary include

• Both qualitative and quantitative information

What are some examples of information recorded in a sleep diary

• Duration of sleep

• Quality of sleep

• Thoughts and feelings before sleep

• Thoughts and feelings after waking

• Behaviours before sleep

• Behaviours after waking

• Number of sleep disruptions

What is a key disadvantage of sleep diaries

• They are subjective and may not be accurate; they also require interpretation by a third person

What is a key advantage of sleep diaries

• They provide qualitative information and detailed descriptions of the sleep experience

What is video monitoring in sleep studies

• The use of camera and audio technology to record an individual while they sleep, tracking sleep and wake periods, movements, activities, and sounds

What is one advantage of video monitoring

• It provides data specific to the individual and is useful for observing behaviours in people with sleep disorders

How can video monitoring increase the validity of physiological data

• By confirming events recorded by devices (e.g., a spike in EMG can be validated by observing bodily movement on video)

What is a disadvantage of video monitoring

• Interpretation can be subjective, such as not knowing if a person getting out of bed is awake or sleep-walking

Why can measuring sleep be difficult

• Some techniques can be disruptive, invasive, or require sleeping in a laboratory setting

How can changes in an individual’s regular sleep patterns affect sleep measurements

• Recording sleep or attaching electrodes can influence the quality and quantity of sleep

What is a consequence of sleep measurement methods on data accuracy

• They may not provide a true reflection of an individual’s usual sleeping patterns

Theory summary

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