Abnormal Epileptiform Patterns Flashcards

Which EEG pattern is characterized by bilateral synchronous 3-Hz spike-and-wave discharges that are typically enhanced by hyperventilation?

Answer: Childhood absence epilepsy

Childhood absence epilepsy classically produces bilateral synchronous 3-Hz spike-and-wave discharges that are strongly activated by hyperventilation.

A patient's EEG shows slow (1–2.5 Hz) spike-and-wave complexes during sleep alongside atonic and tonic seizures. Which syndrome does this pattern most suggest?

Answer: Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is defined by slow (1–2.5 Hz) spike-and-wave, multiple seizure types including atonic and tonic, and intellectual disability.

Hypsarrhythmia on EEG is the interictal hallmark of which epilepsy syndrome?

Answer: West syndrome

Hypsarrhythmia — chaotic high-amplitude activity with multifocal spikes — is the characteristic interictal EEG pattern of West syndrome (infantile spasms).

On EEG, a burst-suppression pattern in a neonate without hypothermia treatment most likely indicates which condition?

Answer: Ohtahara syndrome

Burst-suppression in a neonate (outside therapeutic hypothermia) is a hallmark of Ohtahara syndrome (early infantile epileptic encephalopathy).

Which epileptiform feature specifically distinguishes a true spike from a sharp wave on EEG?

Answer: Duration less than 70 ms vs. 70–200 ms

By convention, a spike has a duration of less than 70 ms, whereas a sharp wave has a duration of 70–200 ms; both may be followed by a slow wave.

Centrotemporal spikes (rolandic spikes) in a child are associated with which EEG characteristic regarding sleep?

Answer: They increase in frequency and may become bilateral during NREM sleep

Centrotemporal spikes in benign epilepsy with centrotemporal spikes (BECTS) are markedly activated and may spread bilaterally during NREM sleep.

A patient has recurrent brief lapses with 3-Hz spike-and-wave that are abruptly terminated by photic stimulation. This response pattern is called:

Answer: Photoparoxysmal response

A photoparoxysmal response refers to generalized epileptiform discharges (spike-and-wave) triggered by intermittent photic stimulation, distinct from the non-epileptiform photomyogenic response.