Another (less likely) thought - migraines can cause transient neurologic symptoms that can be, well, just about anything. Most commonly - nausea, vomiting, visual flashes without there being any reason for those other than the migraine. However, in some cases the migraine can cause more significant and focused neurologic findings, up to and including coma. (Read a research paper about a family in Australia that ends up on ventilators when they get bad migraines, because they get such deep neurologic suppression.)
The diagnosis can be easy to miss, because many folks get the mistaken idea that in order to count as a migraine it HAS to be an awful headache. While some migraines really are killers, others are mild enough that they are mistaken for sinus or tension headaches.
Something to think about if you had even the slightest headache with these spells, especially if the headache was on one side.
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And a point with seizures - it can help docs to decide if really seizure or not if you tell them whether there was either A) loss of control of bowel or bladder with the event; and B) if after the spell there was a period of time where you were particularly tired or foggy.