What EEG pattern is commonly associated with typical absence seizures?

• A. 60 Hz spike-and-slow wave discharges.
• B. Rhythmic theta waves in the occipital region.
• C. 3 Hz spike-and-wave discharges.
• D. Generalized delta activity.

Answer: (C)

The key idea is that typical absence seizures produce a distinctive EEG pattern: generalized, symmetric spike-and-wave discharges occurring at about 3 Hz. Each quick spike is followed by a curved slow wave, and this 3-second rhythm reflects abnormal, synchronized thalamocortical activity that briefly disrupts conscious awareness in children.

Why this matters: absence seizures are brief lapses of consciousness with rapid return to baseline, often with eye blinking or brief staring. The 3 Hz spike-and-wave pattern captures that rapid, generalized, nonfocal disruption across the brain, tied to how thalamic and cortical networks interact abnormally in these episodes.

The other patterns don’t fit the hallmark of typical absence. A 60 Hz spike-and-slow wave pattern is more consistent with electrical interference or a different type of discharge and is not the characteristic absence rhythm. Rhythmic theta waves in the occipital region can be seen with drowsiness or occipital-type phenomena, but they lack the generalized, 3 Hz spike-and-wave signature. Generalized delta activity indicates diffuse brain dysfunction, not the brief, discrete events seen in absence seizures.