EEG Non-Epileptiform Abnormalities 4

Question 1

Which EEG pattern is characterized by diffuse slowing that waxes and wanes and is classically associated with hepatic encephalopathy?

Accepted Answer

Triphasic waves

Answer

Triphasic waves are bilaterally synchronous, frontally dominant, high-amplitude slow waves classically seen in hepatic encephalopathy and other toxic-metabolic states.

Question 2

FIRDA (Frontal Intermittent Rhythmic Delta Activity) is most commonly associated with which condition?

Accepted Answer

Diffuse encephalopathy or deep midline dysfunction

Answer

FIRDA reflects diffuse cerebral dysfunction or deep midline/diencephalic disturbance and is not a focal or epileptiform finding.

Question 3

A burst suppression pattern on EEG is most consistent with which clinical scenario?

Accepted Answer

Severe diffuse cerebral dysfunction such as deep anesthesia or anoxic brain injury

Answer

Burst suppression indicates severely depressed cerebral activity and is seen with deep anesthesia, hypothermia, or severe anoxic-ischemic encephalopathy.

Question 4

Which EEG finding is considered a non-epileptiform abnormality that reflects cortical dysfunction ipsilateral to a structural lesion?

Accepted Answer

Focal polymorphic delta slowing

Answer

Focal polymorphic delta activity indicates underlying structural or physiologic disruption of cortical neurons in that region and is not epileptiform.

Question 5

Electrocerebral inactivity (ECI) on EEG requires that no cerebral electrical activity exceed what amplitude threshold?

Accepted Answer

2 µV

Answer

ECI is defined as no electrical activity over 2 µV recorded with electrode impedances under 10 kΩ using high-sensitivity settings and standard interelectrode distances.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Non-Epileptiform Abnormalities 4