eeg 1- measurement and development

Question 1

What do EEGs measure and reflect?

Answer 1

• Brain electrical activity

- Reflects graded inhibitory (IPSPs) and excitatory postsynaptic potentials (EPSPs)

Question 2

What are the 4 waves and explain them

Answer 2

1. Delta (0.5-3.5hz)- Deep sleep, in very young children and an area of lesion
2. Theta (4-7hz)- Drowsy, more frequent in children, indicator of maturational lag and also marks dysfunction if they’re awake
3. Alpha (8-12hz)- Relaxed waking state, eyes closed, in children indicator of under arousal
4. Beta (13-35hz)- Engaged, mental activity

Question 3

What is monopolar EEG recording

Answer 3

Have active site (head) and reference site (ear)- compare data against eachother

Question 4

What is Bipolar EEG recording

Answer 4

Difference between two active electrode sites

Question 5

What is the international 10-20 system

Answer 5

Its an international convention used to decide where electrodes are placed on scalp
-Positioning based on several physical landmarks (placed at 10% or 20% from nasium positions

Question 6

What is spectral analysis

Answer 6

Analyse EEG in two ways:

1. Time domain- Amount of EEG activity within time
2. Frequency domain- amount of power in a EEG frequency

Question 7

What is Fast Fourier Transformation (Absol and Rel)

Answer 7

Algorithm that the power in each waveform
Absolute power- mag of power in specific frequency band (microvolts squared)
Relative power- Amount of power one band contributes to overall EEG (percentage)

Question 8

What is EEG coherence

Answer 8

How similar the shape of brain wave at two sites

High coherence= two locations are functionally and structurally related

Question 9

How has the EEG been used as a intelligence test

Answer 9

Argued to reflect biological intelligence
Study- gifted 13 yr olds, average 13 yr olds and college students
Gifted has less alpha power then average (same as college students
Alpha decrease= more brain activation and efficient info processing