AED Quiz | Episode 14 | Audio Epilepsy Digest

1. Which statement best distinguishes the seizure-onset zone sampled during intracranial monitoring from the epileptogenic zone? They are interchangeable terms for the first abnormal contact seen during a seizure. The sampled seizure-onset zone is where recorded contacts show earliest ictal activity; the epileptogenic zone is the clinical construct of the tissue or network whose treatment is necessary and sufficient for seizure freedom and is not directly measured by one test. The epileptogenic zone is defined only by the structural lesion on MRI. The seizure-onset zone always contains every node required for seizure propagation.

Correct answer: B. Intracranial recordings describe activity at sampled contacts. The epileptogenic zone is inferred by integrating the full presurgical evaluation and cannot be equated automatically with one recorded onset or one lesion.

2. When is S-E-E-G most useful in the decision pathway described in this episode? When the team wants an unrestricted survey of the entire brain before forming a hypothesis. Whenever scalp EEG and MRI agree, regardless of whether invasive findings could change treatment. When focused, bounded alternatives remain, electrode sampling can test them, and the result could change the treatment plan. When the goal is to prove that no unsampled seizure-onset tissue exists.

Correct answer: C. S-E-E-G is spatially limited sampling. Its value depends on a focused, actionable hypothesis and explicit acknowledgment of what was not sampled; a negative sampled region does not exclude activity elsewhere.

3. Which statement best represents treatment-oriented epilepsy surgery conference reasoning? A visible lesion should automatically determine the procedure. Once a seizure-onset contact is identified, functional and cognitive risks become secondary. Neuromodulation should be selected whenever resection is technically difficult. The team integrates targetability, network distribution, eloquent function, cognitive and neurologic risk, expected benefit, residual uncertainty, and patient goals; no procedure can be an appropriate outcome.

Correct answer: D. The conference decision is conditional rather than automatic. It compares resection, ablation, disconnection, neuromodulation, and no procedure against the same benefit-risk-uncertainty framework.

Fellow Bootcamp: From EMU to SEEG to Surgery

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