EEG ICU and Continuous EEG Monitoring 5

Question 1

In a mechanically ventilated ICU patient, which artifact most commonly mimics rhythmic ictal activity on cEEG and must be systematically excluded?

Accepted Answer

Ventilator artifact

Answer

Ventilator artifact produces rhythmic movement-related potentials synchronous with breathing cycles that can closely resemble rhythmic epileptiform activity, especially in frontal and central channels.

Question 2

Which of the following best defines the 'treatment threshold' concept for periodic discharges on the ictal-interictal continuum?

Accepted Answer

Treatment decisions depend on clinical context, imaging, and metabolic variables rather than EEG alone

Answer

The ictal-interictal continuum requires clinical integration — treatment thresholds depend on the overall clinical picture, not solely on discharge frequency or morphology.

Question 3

What does a 'stimulus-induced rhythmic, periodic, or ictal discharges' (SIRPIDs) pattern indicate in a comatose ICU patient?

Accepted Answer

Preserved cortical reactivity with potential for seizure provocation

Answer

SIRPIDs indicate that the cortex retains reactivity to external stimuli but responds with potentially epileptiform activity, suggesting an irritable cortex susceptible to seizure induction.

Question 4

In the setting of acute liver failure, which EEG pattern is characteristic and reflects hepatic encephalopathy grade III-IV?

Accepted Answer

Frontal dominant triphasic waves with anterior-to-posterior lag

Answer

Triphasic waves with a characteristic anterior-to-posterior phase lag are the classic EEG signature of moderate-to-severe hepatic encephalopathy, reflecting diffuse metabolic cortical dysfunction.

Question 5

During cEEG monitoring in a TBI patient, what does the appearance of 'breach rhythm' indicate?

Accepted Answer

Skull defect causing amplitude enhancement and frequency changes

Answer

Breach rhythm occurs over skull defects (craniectomy or fracture) where the missing bone allows higher amplitude and sharper-appearing waveforms due to reduced electrical filtering.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG ICU and Continuous EEG Monitoring 5