EEG Ambulatory 4

Question 1

When a patient on ambulatory EEG reports a suspected seizure event via the event button but the recording shows no ictal activity, the MOST likely explanation is:

Accepted Answer

The event was a non-epileptic psychogenic episode

Answer

Non-epileptic psychogenic events (PNES) are a common finding when patient-reported events lack EEG correlate during ambulatory monitoring.

Question 2

A 24-hour ambulatory EEG uses a sample rate of 256 Hz. What is the highest frequency that can be faithfully represented according to the Nyquist theorem?

Accepted Answer

128 Hz

Answer

The Nyquist theorem states the maximum representable frequency is half the sampling rate, so 256 Hz ÷ 2 = 128 Hz.

Question 3

Which of the following activities is MOST likely to produce muscle artifact that obscures the EEG during an ambulatory recording?

Accepted Answer

Chewing food during a meal

Answer

Chewing activates the temporalis and masseter muscles, generating high-amplitude EMG artifact that directly overlies temporal EEG electrodes.

Question 4

A patient's ambulatory EEG diary notes 'episode of deja vu lasting 30 seconds' at 14:22. The technologist reviewing the recording should FIRST:

Accepted Answer

Navigate to 14:22 and review the corresponding EEG channel data

Answer

The technologist should correlate the diary timestamp with the EEG data at that exact time to look for ictal or interictal changes.

Question 5

During ambulatory EEG review, runs of rhythmic 4–7 Hz theta activity appearing symmetrically during an afternoon recording segment are MOST consistent with:

Accepted Answer

Normal drowsiness

Answer

Symmetric theta slowing during daytime hours is a normal finding associated with drowsiness or light sleep stage N1.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Ambulatory 4