Department of Neurology

Did a seizure occur?

Q: My son had partial seizures five to ten years ago. It has been years since he has shown any symptoms of those seizures.

There is a question as to whether he may have suffered tonic clonic seizures recently. Is there any test to prove that he either did or, more importantly, did not have a tonic-clonic seizure. If no test is definitive, are there indiicative tests?

I appreciate any guidance you could offer.


A: There are no tests that prove a seizure occurred, with the exception of recording a seizure during an EEG or videomonitoring study. Some EEG patterns that may be seen on routine EEG studies will suggest a a predispostion to a certain seizure type, but would not indicate if and when a seizure has or will occur. Treating epilepsy is much like detective work; you doctor must gather the best information available to determine whether a seizure occurred. The diagnosis depends on the ability of your doctor to obtain a carefull history of the spells from witnesses. If the spell was totally unwitnessed, it may be impossible to absolutely know the cause.

Nonetheless, certain clinical signs may strongly suggest seizures. For example, if he had a prolonged confusion or lethargy after the spell, this would suggest a seizure occurred. If blood was drawn immediately after the episode, chemistries may show evidence of poor respiration, such as a low blood pH or low blood oxygen.

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