Department of Neurology

Does an EEG diagnose epilepsy?

Q: Is it possible to have a diagnosis of temporal lobe epilepsy without ever having a seizure of any kind, or any hallucinations, but based purely on an EEG? What are the other indicators of this kind of epilepsy? Thank you

A: Epilepsy is a clinical diagnosis, based on appropriate history and findings. The EEG does not replace clinical judgement -- an abnormal EEG alone does not diagnose epilepsy, nor does a normal one exclude epilepsy. The only exception to this would be if an actual seizure was recorded during the EEG study.

If you have never had any spells of any kind, it would be difficult to say that you have epilepsy. Nonetheless, I presume you had an EEG for some reason, and if it was for spells of some sort, the EEG findings may have supported the diagnosis of epilepsy in the judgement of your physicians.

Typical symptoms of "temporal lobe seizures" (complex partial seizures) include: staring, loss of awareness, automatisms (semipurposeful repetitive movements), forced memories, deja vu, disorientation. However, these symptoms may occur in other illnesses, so the diagnosis should be made by a qualified physician.

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