EEG- Measurement & Development Flashcards
How is EEG data practically used?
diagnostic marker of ADHD, medication effects, outcome measure for training studies, basis for all ERP studies, PPT
What do EEGs measure?
Measure of brain electrical activity, recorded during resting states and active processing.
Measuring outcome of action potential: NTs bind to post-synaptic receptors -> headed IPSPs and EPSPs (measure from EEG)
Where does rhythmical cortical EEG activity come from?
interaction between the thalamus and cortex
ARAS primary driver for cortical EEG
Who described the first “brain wave”?
Caton (1875) in rabbits and monkeys- primarily slow wave activity (probably delta)
Who described the first EEG activity in humans?
Berger (1929)- 2 basic wave patterns- large regular (alpha), smaller irregular (beta)
Who later discovered delta and theta?
William Grey Walter- discovered delta waves during sleep and theta
What are the characteristics of delta waves?
0.5-3.5Hz, 20-200uV, deep sleep, in very young children and in area of a lesion
What are the characteristics of theta waves?
4-7Hz, 20-100uV, more frequent in children, indicator of maturational lag and general marker of patient dysfunction (if patient alert & awake)
What are the characteristics of alpha waves?
8-12Hz, 20-60uV, relaxed waking state, eyes closed, mental inactivity, posterior dominant
What are the characteristics of beta waves?
13-25Hz, 2-20uV, mental activity, frontocentral
What are some less common waves?
Gamma- 30-120Hz? not heavily studied
Others: kappa, lambda, Mu
Whats involved in a monopolar EEG recording?
Most frequently used. reference sit to compare active data against (usually on ear)
Whats involved in a bipolar EEG recording?
Difference between 2 active electrodes (less frequently used)
What is the international 10-20 system?
international convention that allows comparison of results- electrodes used in measurements between several point, with most placed at intervals of 10% or 20% of the distance
Electrode cap has distances built in
(also international 10-10 with more electrodes)
What is spectral analysis?
Analysing the EEG- two ways:
- Time Domain: amount of EEG activity within a time (Hz)
- Frequency Domain: Amount of power within a given EEG frequency (uV)