In the EEG, a 3 Hz spike-and-wave discharge pattern occurring in bursts of 5–20 seconds with abrupt onset and offset, associated with brief staring spells and eyelid fluttering in a child, is most characteristic of which condition?

• A Childhood absence epilepsy ✓
• B Juvenile myoclonic epilepsy
• C West syndrome (infantile spasms)
• D Benign childhood epilepsy with centrotemporal spikes

Explanation

Childhood absence epilepsy is characterized by 3 Hz (2.5–4 Hz) generalized spike-and-wave discharges on EEG with abrupt onset/offset, corresponding exactly to clinical absence seizures with staring and automatisms. The mechanism involves thalamocortical oscillatory circuits with T-type Ca2+ channel involvement. Juvenile myoclonic epilepsy shows 4–6 Hz polyspike-and-wave; West syndrome shows hypsarrhythmia; benign childhood epilepsy shows centrotemporal spikes.

Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.

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