Bcia Exam

Front 1

aliasing

Back 1

a sampling rate which is too slow will make the signal appear to be running at a slower frequency than it actually is

Front 2

low pass filter

Back 2

meant only to let through waves below a cut point; for many instruments this is set at 32 HZ

Front 3

band pass filter

Back 3

frequency ranges chosen by the practitioner to use for statistical comparison or for neurofeedback

Front 4

sequential or bipolar montage

Back 4

two electrodes each attached to an active scalp site; shows the difference in activity between the two active sites on the head

Front 5

resistence

Back 5

measure of how much circuit components restrict the passage of a direct current

Front 6

Variance

Back 6

is the square of the SD/standard deviation

Front 7

Impedance

Back 7

resistance of circuit elements to the passage of alternating current (AC)

Front 8

Referential (monopolar) montage

Back 8

shows activity at one active site on head by subtracting noise or other artifact common to both sensors (ground, reference)

Front 9

Power

Back 9

voltage (v) * current (I)

Front 10

Ohm's Law

Back 10

the amount of current or amperes in a conductor is equal to the voltage (v) the "push" or "pull" divided by the resistance (R) in ohms

Front 11

sensitivity

Back 11

ratio of input voltage to the change in the signal as it is displayed

Front 12

capacitance

Back 12

storage of electrical energy on 2 parallel plates of conductive material separated by an insulating material

Front 13

electrode impedence

Back 13

resistance to alternating electrical current flow

Front 14

Gain

Back 14

refers to a ratio of the voltage of a signal at the output of the amplifier to the voltage of the signal at the input of that amplifier
10V/10uv = 1 million

Front 15

Phase

Back 15

calculation of the time shift between EEG activity in two brain regions; delays increase with age
short front to back delays correlate with higher IQs

Front 16

Pearson Product Correlatin Coefficient or Comodulation

Back 16

degree of association in magnitude between signals from 2 different sources or sites

Front 17

Relative Power

Back 17

comparison of frequency band power to total EEG power

Front 18

Power

Back 18

uV squared within a band or total EEG power

Front 19

Amplitude

Back 19

amount of enery of electrical discharge measured within a specific frequency band or the EEG as a whole

Front 20

Common Reference Montage

Back 20

excellent for detection of widely distributed currents and for analyzing aymmetry. Also good for the detection of artifacts

Front 21

Optical isolation

Back 21

Process where you separate the encoder from the computer by a glass wire. Digital current from the encoder is changed to an optical form for transmission to the computer

Front 22

sequential (bipolar) and Laplacian montages

Back 22

montage good for viewing highly localized activity

Front 23

montage/reformatting

Back 23

process where we take different views of the same data, refrencing one electrode site to another or combination of sites

Front 24

Fast Fourier Transform Filter (FFT)

Back 24

take the EEG information and mathmatically transform it to give it an average voltage for a specific frequency over a specified time frame.

Front 25

What are the 3 types of digital filters?

Back 25

1. Final impulse response (FIR)
2. Infinite impulse response (IIR)
3. Fast Fourier Transform (FFT)

Front 26

Nyquist principle

Back 26

The maximum frequency that can be reconstructed in a filter is based on this. It is half the sample rate frequency

Front 27

Nyquist principle

Back 27

states that the sampling rate must be at least twice the maximum bandwidth of the analog signal in order to allow the signal to be completely represented.

Front 28

Common mode rejection

Back 28

ratio of common mode input voltage divided by the output voltage. Ratio should be greater than 100,000.

Front 29

High pass band filter

Back 29

meant to attenuate the waves or reduce the amplitude of the waves that come in at a frequency below the cut-off. It lets "pass-through" waves higher than the cut-off frequency

Front 30

Sampling

Back 30

change the alternating analog current to the digital form that the computer can work with

Front 31

Preamplifier

Back 31

Amplifies the microvolt different by more than 100,000 times and does not amplify other electrical signals

Front 32

electrical charge

Back 32

refers to the negative charge carried by electrons

Front 33

Sensitivity

Back 33

ratio of input voltage to the change in the signal as it is displayed

Front 34

Impedence is measured using:

Back 34

alternating current in the alpha range

Front 35

Impedence requires measurement of several factors including:

Back 35

resistance of the conductor, capacitance, inductance, and the frequency of the alternating current

Front 36

What does current measure?

Back 36

the rate of transfer of electric charge from one point to another

Front 37

Compares adjacent pairs of electrodes in the 10-20 system; these may be either longitudinal pairs (F3-C3) or transverse pairs, going across the head (C3-CZ)

Back 37

Sequential or Bipolar Montage

Front 38

Active reference montage using common average reference, will reference an active electrode to an average of all other electrodes

Back 38

Laplacian or Global Average Montage

Front 39

Will reference to the average of the electrodes immediately surrounding each active electrode.

Back 39

Laplacian or Hjorth Montage

Front 40

What is power?

Back 40

The square of magnitude (average amplitude for a specific epoch) within a frequency band over resistance

Front 41

Absolute amplitude in scalp EEG

Back 41

amount of electrical activity in a given frequency band

Front 42

Relative or percent power

Back 42

amount of EEG band power as a percentage of the total signal