RPSGT RPSGT Electroencephalography & Signal Interpretation 4 — Questions and Answers
Question 1: Which EEG frequency band is most prominently associated with active cognitive processing and problem-solving?
- Delta (0.5–4 Hz)
- Theta (4–8 Hz)
- Alpha (8–13 Hz)
- Beta (13–30 Hz) (Correct answer)
Correct answer: Beta (13–30 Hz)
Beta activity predominates during active mental engagement, concentration, and problem-solving tasks.
Question 2: A 60-Hz artifact appearing on EEG channels is most likely caused by:
- Patient movement
- Electrode impedance mismatch
- AC electrical interference (Correct answer)
- Muscle artifact from the frontalis
Correct answer: AC electrical interference
60-Hz artifact results from alternating current (AC) electrical interference from nearby equipment or poor grounding.
Question 3: During N3 sleep, the EEG is characterized by:
- Sleep spindles and K-complexes
- Low-voltage mixed-frequency activity
- High-amplitude slow waves occupying ≥20% of the epoch (Correct answer)
- Sawtooth waves and REMs
Correct answer: High-amplitude slow waves occupying ≥20% of the epoch
N3 is defined by slow-wave activity (0.5–2 Hz, ≥75 µV) comprising at least 20% of the 30-second epoch.
Question 4: Vertex sharp waves (V waves) in a sleep study are most characteristic of which sleep stage?
- REM sleep
- N1 sleep (Correct answer)
- N2 sleep
- N3 sleep
Correct answer: N1 sleep
Vertex sharp waves are electropositive transients maximal at the vertex and are a hallmark of N1 sleep.
Question 5: A HEOG (horizontal electro-oculogram) montage detects eye movements by placing electrodes:
- Above and below each eye
- At the outer canthi of each eye (Correct answer)
- At the inner canthi of each eye
- At the supraorbital ridge bilaterally
Correct answer: At the outer canthi of each eye
HEOG electrodes are placed at the outer canthi (lateral edges) of each eye to detect lateral eye movements.
Question 6: Which artifact is characterized by rhythmic, high-frequency bursts on EEG channels that correlate with the pulse rate?
- Sweat artifact
- ECG artifact
- Electrode pop artifact
- Pulse artifact (Correct answer)
Correct answer: Pulse artifact
Pulse artifact appears as rhythmic slow waves or spikes on EEG caused by an electrode placed over a pulsating blood vessel.
Question 7: In referential (monopolar) EEG recording, the reference electrode should ideally be placed at a site that is:
- Maximally active electrically
- Electrically neutral or minimally active (Correct answer)
- Directly over the frontal lobe
- On the same side as the active electrode
Correct answer: Electrically neutral or minimally active
A reference electrode should be electrically neutral to accurately reflect the potential of the active electrode without introducing its own signal.
RPSGT RPSGT Electroencephalography & Signal Interpretation 4
Which EEG frequency band is most prominently associated with active cognitive processing and problem-solving?