Non-Epileptiform Abnormalities Flashcards
7 cards from real EEG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Non-Epileptiform Abnormalities flashcards as text
Which EEG pattern is characterized by diffuse slowing that waxes and wanes and is classically associated with hepatic encephalopathy?
Answer: Triphasic waves
Triphasic waves are bilaterally synchronous, frontally dominant, high-amplitude slow waves classically seen in hepatic encephalopathy and other toxic-metabolic states.
FIRDA (Frontal Intermittent Rhythmic Delta Activity) is most commonly associated with which condition?
Answer: Diffuse encephalopathy or deep midline dysfunction
FIRDA reflects diffuse cerebral dysfunction or deep midline/diencephalic disturbance and is not a focal or epileptiform finding.
A burst suppression pattern on EEG is most consistent with which clinical scenario?
Answer: Severe diffuse cerebral dysfunction such as deep anesthesia or anoxic brain injury
Burst suppression indicates severely depressed cerebral activity and is seen with deep anesthesia, hypothermia, or severe anoxic-ischemic encephalopathy.
Which EEG finding is considered a non-epileptiform abnormality that reflects cortical dysfunction ipsilateral to a structural lesion?
Answer: Focal polymorphic delta slowing
Focal polymorphic delta activity indicates underlying structural or physiologic disruption of cortical neurons in that region and is not epileptiform.
Electrocerebral inactivity (ECI) on EEG requires that no cerebral electrical activity exceed what amplitude threshold?
Answer: 2 µV
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.
Which pattern is characterized by generalized, bisynchronous rhythmic delta activity seen predominantly over posterior head regions and is a non-epileptiform finding?
Answer: OIRDA (Occipital Intermittent Rhythmic Delta Activity)
OIRDA consists of occipitally predominant rhythmic delta bursts, is associated with encephalopathy or posterior fossa lesions, and is not inherently epileptiform.
In a comatose patient, the presence of sleep architecture elements such as sleep spindles or K-complexes on EEG suggests which prognostic implication?
Answer: Relatively preserved thalamocortical function and potentially better prognosis
Preservation of sleep architecture in coma indicates intact thalamocortical circuitry and generally correlates with a more favorable neurological prognosis.