EEG - Electroencephalography Abnormal Epileptiform Patterns Questions and Answers

Question 1

An 8-year-old child presents with frequent staring spells.
The EEG recording shows bursts of generalized, synchronous, and symmetric 3 Hz spike-and-wave discharges that are easily provoked by hyperventilation.
What is the most likely clinical correlation?

Accepted Answer

Childhood absence epilepsy

Answer

Lennox-Gastaut syndrome

Answer

Juvenile myoclonic epilepsy

Answer

Benign Rolandic epilepsy

Question 2

According to the American Clinical Neurophysiology Society (ACNS) guidelines, an epileptiform discharge is classified as a 'sharp wave' based on which of the following duration ranges?

Accepted Answer

70-200 milliseconds

Answer

< 20 milliseconds

Answer

> 200 milliseconds

Answer

20-70 milliseconds

Question 3

A 9-month-old infant is evaluated for clusters of sudden, brief flexor spasms. The interictal EEG shows a chaotic, high-voltage, and disorganized pattern of asynchronous slow waves and multifocal spikes. Which of the following terms best describes this EEG pattern?

Accepted Answer

Hypsarrhythmia

Answer

Burst-suppression

Answer

Triphasic waves

Answer

Slow spike-and-wave

Question 4

An EEG on a 10-year-old child shows high-amplitude, diphasic sharp waves that occur independently over the centrotemporal regions (C3/T3 and C4/T4). The discharges become significantly more frequent during drowsiness and sleep. This pattern is pathognomonic for which epilepsy syndrome?

Accepted Answer

Self-limited Epilepsy with Centrotemporal Spikes (SeLECTS)

Answer

Lennox-Gastaut Syndrome (LGS)

Answer

Childhood Absence Epilepsy (CAE)

Answer

Juvenile Myoclonic Epilepsy (JME)

Question 5

An EEG performed on a patient with an acute left-hemispheric stroke shows stereotyped sharp waves recurring every 1-1.5 seconds, confined to the left cerebral hemisphere. This pattern is best described as:

Accepted Answer

Periodic Lateralized Discharges (PLEDs)

Answer

Generalized Periodic Discharges (GPDs)

Answer

Burst-Suppression

Answer

Triphasic Waves

Question 6

In a comatose patient following an anoxic brain injury, the EEG shows periods of high-voltage, mixed-frequency activity lasting 1-3 seconds, which are separated by periods of profound voltage attenuation (<10 µV) lasting 4-8 seconds. This pattern is known as:

Accepted Answer

Burst-suppression

Answer

Hypsarrhythmia

Answer

Alpha coma

Answer

Slow spike-and-wave