EEG Abnormal Epileptiform Patterns 2

Question 1

Which EEG pattern is characterized by a spike followed by a slow wave complex occurring at approximately 3 Hz?

Accepted Answer

Generalized 3 Hz spike-and-wave

Answer

The classic 3 Hz spike-and-wave pattern is the hallmark of childhood absence epilepsy, appearing as generalized, synchronous, bilateral discharges.

Question 2

What is the typical duration criterion for an EEG spike?

Accepted Answer

20 to 70 milliseconds

Answer

By IFCN definition, a spike has a duration of 20 to 70 milliseconds, distinguishing it from sharp waves which last 70 to 200 milliseconds.

Question 3

Periodic lateralized epileptiform discharges (PLEDs) are most commonly associated with which condition?

Accepted Answer

Acute structural brain lesion such as stroke

Answer

PLEDs (now called lateralized periodic discharges or LPDs) are strongly associated with acute destructive brain lesions, most commonly stroke, and may indicate ongoing seizure activity.

Question 4

Which epileptiform pattern consists of high-amplitude, chaotic, multifocal spikes and slow waves seen in infantile spasms?

Accepted Answer

Hypsarrhythmia

Answer

Hypsarrhythmia is the classic interictal EEG pattern of infantile spasms (West syndrome), characterized by high-amplitude disorganized slow waves with multifocal spikes.

Question 5

What feature best distinguishes a benign epileptiform transient of sleep (BETS) from a pathological epileptiform discharge?

Accepted Answer

BETS are typically small, isolated, and lack an after-going slow wave

Answer

BETS (also known as small sharp spikes or SSS) are low-amplitude, brief, isolated transients without after-going slow waves, occurring during drowsiness and light sleep, and are considered benign normal variants.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Abnormal Epileptiform Patterns 2