Chapter 6B Flashcards
What kind of measures are EEG’S, EMG’S, AND EOG’S.
EEG’S, EOG’S, AND EMG’S, are considered to be objective physiological measures, that can provide reliable, unbiased, and quantitative data about an individuals state of consciousness.
Limitations of these devices.
- They do not provide qualitative detail about the personal experience of sleep, such as the experience of feelings and thoughts.
- The findings can lack validity at times, as changes in physiological responses can be due to other factors other than a change in consciousness.
Limitations of sleep diaries and video monitoring.
- These do not provide direct observation of sleep, and thus the accuracy and reliability of such measures may be limited.
Why can measuring sleep be difficult?
Measuring sleep can be difficult, as some techniques may be disruptive, invasive, or may require an individual to sleep in a sleep laboratory, for a period of time. Changes to an individuals sleep patterns, such as having electrodes attached to an individuals head whilst asleep, can affect the quality and quantity of an individuals sleep.
Describe an electroencephalograph (EEG).
An EEG is a device that detects, amplifies, and records the electrical activity of the brain. When neurons communicate, they emit electrical impulses. These impulses are detected by an EEG and presented as brain waves, thus helping you indicate the level of consciousness an individual may be experiencing.
Describe the likely brainwaves in REM sleep.
Higher frequency and lower amplitude in REM sleep.
Brainwaves in NREM stage 1.
Higher frequency and lower amplitude in NREM stage 1, but lower frequency, and higher amplitude than normal waking consciousness.
Brainwaves in NREM stage 2.
Medium frequency and medium amplitude.
Brainwaves in NREM stage 3.
Low frequency and high amplitude.
Strengths of EEG’s as a measure of sleep.
EEG’s as a measure of sleep is useful for sleep studies, or diagnoses of patients with a brain damage or neurological disorder.
Limitations of EEG’s.
It measures neural activity underneath a thick a hard skull, and thus may not be entirely precise. It also does not pinpoint any functional or dysfunctional areas of the brain as well as neuroimaging techniques such as fMRI.
Describe electromyography (EMG)
An EMG detects, amplifies, and records the electrical activity of the body’s muscles. By attaching electrodes to the skin, above the body’s muscles, under investigation, the movement and tension of muscles is recorded. The movement and tension of muscles can be used to identify the different stages of sleep an individual is experiencing, through gathering information on how active an individuals muscles are.
What may an EMG likely show in REM sleep
EMG recordings in REM sleep are likely to show low activity, due to there being low levels of physiological activity in this stage of sleep.
What may an EMG likely show in NREM sleep.
An EMG is likely to show medium/moderate activity, due to there being some physiological activity during this stage of sleep. However, as NREM sleep stages progress, an EMG is likely to show lower activity, as movement is less likely to occur.
Describe what a Electro-oculography (EOG) is
An EOG detects, amplifies, and records the electrical activity of the muscles surrounding the eyes, which is used to infer eye movements. EOG’s are helpful for investigating what stage of sleep an individual is experiencing. During REM sleep, EOG’s are likely to show high activity, whereas, in NREM sleep, they are likely to show lower activity.
