Abnormal Epileptiform Patterns Flashcards

Which EEG finding is the ictal correlate of epilepsia partialis continua (Kojewnikow syndrome)?

Answer: Continuous focal rhythmic delta activity with embedded spikes over the motor cortex

Epilepsia partialis continua produces continuous or near-continuous focal rhythmic discharges, often with embedded spikes, localized to the contralateral motor cortex.

On a neonatal EEG, which feature best distinguishes a seizure discharge from a normal sharp transient?

Answer: Evolution in frequency, amplitude, or spatial distribution over time

Neonatal seizures are defined by electrographic evolution — a clear change in frequency, morphology, or field — rather than by a fixed amplitude or sleep-state rule.

Generalized paroxysmal fast activity (GPFA) during slow-wave sleep is the characteristic ictal correlate of which seizure type in Lennox-Gastaut syndrome?

Answer: Tonic seizures

Tonic seizures in Lennox-Gastaut syndrome are associated with generalized paroxysmal fast activity (GPFA, 10–25 Hz) predominantly during NREM sleep.

A 6-Hz spike-and-wave burst lasting less than 2 seconds seen in a drowsy young adult is most consistent with:

Answer: Phantom spike-and-wave (benign variant)

The 6-Hz 'phantom' spike-and-wave is a benign normal variant in drowsy young adults and should not be misinterpreted as pathological epileptiform activity.

Which EEG pattern during absence status epilepticus distinguishes it from typical 3-Hz absence discharges?

Answer: The discharges become fragmented, irregular, and slower (< 2.5 Hz) over time

During prolonged absence status epilepticus, the initially regular 3-Hz spike-and-wave tends to slow, fragment, and become irregular as status continues.

In juvenile myoclonic epilepsy (JME), the EEG hallmark is polyspike-and-wave discharges typically at which frequency?

Answer: 4–6 Hz

JME is characterized by generalized polyspike-and-wave complexes at 4–6 Hz, typically maximal in the morning and activated by sleep deprivation.

An EEG shows electrical status epilepticus during slow-wave sleep (ESES), with spike-wave index exceeding 85%. This pattern underlies which syndrome?

Answer: Continuous spike-waves during slow sleep (CSWS) / Landau-Kleffner syndrome spectrum

ESES (spike-wave index > 85% during NREM sleep) is the electrographic hallmark of CSWS and Landau-Kleffner syndrome, associated with acquired cognitive or language regression.