Which diagnostic test is most useful to classify seizure type and guide treatment?

• A. Electroencephalography (EEG)
• B. Brain MRI
• C. Computed tomography (CT) scan
• D. Positron emission tomography (PET)

Answer: (A)

The key test for classifying seizure type and guiding treatment is EEG because it directly measures the brain’s electrical activity and reveals patterns that distinguish focal seizures from generalized ones. EEG can show spikes, sharp waves, or rhythmic discharges that indicate where seizures start and how they spread, which helps determine the most effective medications and whether additional strategies (like surgical planning) might be needed. When you combine EEG with video to capture events, you get a clear picture of both the clinical presentation and the electrical activity, making it easier to tailor treatment to the specific seizure type.

Imaging like brain MRI is crucial for identifying structural causes (such as tumors or malformations) that may influence prognosis and surgical options, but it doesn’t classify seizure type the way EEG does. CT scans are often used acutely to rule out bleeding or other emergent issues, not primarily to classify seizures. PET scans provide metabolic information useful in complex, nonlocalizing cases or pre-surgical workups, but they’re not the first tool for determining seizure type and guiding initial treatment decisions.