Which EEG pattern is most characteristic of childhood absence epilepsy and what is the typical age of onset?

• A. Generalized Delta Activity
• B. Hypsarrhythmia
• C. Burst-Suppression Pattern
• D. 3 Hz Generalized Spike-and-Wave Discharges

Answer: (D)

Absence seizures in children show a distinctive EEG signature: generalized, synchronous spike-and-wave discharges occurring at about 3 per second. This 3 Hz spike-and-wave pattern reflects abnormal thalamocortical oscillations that briefly disrupt consciousness, which is the hallmark of childhood absence epilepsy. The typical age of onset is in the school-age years, commonly between about 4 and 8 years old, with many cases beginning around 5–7 years. By contrast, patterns like hypsarrhythmia occur with infantile spasms, generalized delta activity indicates a slow, nonspecific background often seen in diffuse cerebral dysfunction, and burst-suppression appears in severe encephalopathy or coma. So the 3 Hz generalized spike-and-wave discharges in a child around 5–7 years old best match childhood absence epilepsy.