Electroencephalography (EEG) & Evoked
Potentials Questions With Solutions
1. EEG defined
a. The EEG is a measurement of ?. These voltage fluctuations are called?
b. EEG recording:
i. In humans, the electrodes are small metal disks pasted to the surface of the scalp by an
electricity conducting gel.
ii. There are two electrodes plugged into each amplifier on the EEG machine. The EEG recorder
detects the voltage differences between the recording and reference electrode for each channel of
detection. The amplifier compares the two electrode signals coming into it and cancels out
signals that are the same. Therefore the EEG signal is the difference in ?
iii. One electrode pair is referred to as a ?. Modern EEG recordings have from ? channels to
produce a multichannel recording as shown here.
iv. The placement of the electrodes is important because the closer the electrodes are to each
other the ?. If the electrodes are too close, the EEG channel will display a straight line.
Therefore, when r -voltage fluctuations at the surface of the scalp generated by the
electrical activity of the brain
- brain waves and are recordings of voltage difference versus time.
, Electroencephalography (EEG) & Evoked
Potentials Questions With Solutions
-electrical activity detected by two electrodes.
-channel
-8 to 40
-less differences in their brain waves
Figure 3: Standard placement of electrodes on a subject for multichannel EEG recording.
Abbreviations: A, auricle; C, central; Cz, vertex; F, frontal; FP frontal pole; O, occipital; P,
parietal; T, temporal.
i. The voltage emitted from the scalp is on the order of microvolts (10-6 volts). The EEG
amplifiers increase this signal by a factor of several hundred thousand (105) for detection and
recording.
ii. Detected signals are either traced on strip chart paper or, more likely nowadays, are passed
through an analog-to-digital processor and stored in digital format.
iii. The digitized data can then be analyzed by Fourier transforms (FT) and filtering. FT is a
mathematical way to ?
Potentials Questions With Solutions
1. EEG defined
a. The EEG is a measurement of ?. These voltage fluctuations are called?
b. EEG recording:
i. In humans, the electrodes are small metal disks pasted to the surface of the scalp by an
electricity conducting gel.
ii. There are two electrodes plugged into each amplifier on the EEG machine. The EEG recorder
detects the voltage differences between the recording and reference electrode for each channel of
detection. The amplifier compares the two electrode signals coming into it and cancels out
signals that are the same. Therefore the EEG signal is the difference in ?
iii. One electrode pair is referred to as a ?. Modern EEG recordings have from ? channels to
produce a multichannel recording as shown here.
iv. The placement of the electrodes is important because the closer the electrodes are to each
other the ?. If the electrodes are too close, the EEG channel will display a straight line.
Therefore, when r -voltage fluctuations at the surface of the scalp generated by the
electrical activity of the brain
- brain waves and are recordings of voltage difference versus time.
, Electroencephalography (EEG) & Evoked
Potentials Questions With Solutions
-electrical activity detected by two electrodes.
-channel
-8 to 40
-less differences in their brain waves
Figure 3: Standard placement of electrodes on a subject for multichannel EEG recording.
Abbreviations: A, auricle; C, central; Cz, vertex; F, frontal; FP frontal pole; O, occipital; P,
parietal; T, temporal.
i. The voltage emitted from the scalp is on the order of microvolts (10-6 volts). The EEG
amplifiers increase this signal by a factor of several hundred thousand (105) for detection and
recording.
ii. Detected signals are either traced on strip chart paper or, more likely nowadays, are passed
through an analog-to-digital processor and stored in digital format.
iii. The digitized data can then be analyzed by Fourier transforms (FT) and filtering. FT is a
mathematical way to ?
