EEG - Electroencephalography Activation Procedures Questions and Answers

Question 1

The primary physiological mechanism by which hyperventilation (HV) activates epileptiform discharges is through inducing:

Accepted Answer

Respiratory alkalosis and cerebral vasoconstriction.

Answer

Respiratory acidosis and cerebral vasodilation.

Answer

A decrease in heart rate and systemic blood pressure.

Answer

Increased cerebral blood flow and oxygenation.

Question 2

During intermittent photic stimulation (IPS) on a 15-year-old patient, the EEG shows bursts of generalized spike-and-wave and polyspike-and-wave discharges that are time-locked to the flash stimulus, outlast the stimulus, and are self-sustaining. This response is best described as a:

Accepted Answer

Photoparoxysmal response.

Answer

Photomyogenic response.

Answer

Photic driving response.

Answer

Lambda wave activation.

Question 3

A 72-year-old patient is referred for a routine EEG. Their medical history includes a recent ischemic stroke one week ago, severe chronic obstructive pulmonary disease (COPD), and sickle cell trait. Which activation procedure is specifically contraindicated for this patient?

Accepted Answer

Hyperventilation.

Answer

Eye opening and closing.

Answer

Photic stimulation.

Answer

Sleep recording.

Question 4

Which of the following describes the typical, normal response to hyperventilation in a healthy 8-year-old child's EEG?

Accepted Answer

A buildup of generalized, rhythmic, high-amplitude delta and theta slowing.

Answer

The appearance of generalized 3 Hz spike-and-wave discharges.

Answer

Attenuation of the posterior dominant rhythm with no other changes.

Answer

Development of focal sharp waves over the temporal regions.

Question 5

The primary reason for obtaining a sleep recording during an EEG is that sleep, particularly non-REM sleep, is a potent activator of:

Accepted Answer

Interictal epileptiform discharges.

Answer

Alpha coma patterns.

Answer

Photoparoxysmal responses.

Answer

Triphasic waves.

Question 6

When performing intermittent photic stimulation (IPS) according to standard laboratory protocols, what is the most appropriate action for the technologist?

Accepted Answer

Present flashes at varying frequencies, typically starting low and increasing, testing with both eyes open and eyes closed.

Answer

Instruct the patient to keep their eyes open for the entire duration of the procedure.

Answer

Continue flashing for at least 30 seconds after a generalized discharge appears to confirm its persistence.

Answer

Begin with the highest frequency (30 Hz) and decrease in 5 Hz increments.