In the majority of cases when a patient has a seizure it can be seen on the EEG. It may require extra electrodes, and the expertise of a neurologist who specializes in EEG. If there is still a question regarding your sisters spells, perhaps an evaluation at a large epilepsy centet would be reasonable. We have a wonderful Epilepsy program at the Cleveland Clinic Foundation, and see patients from all over the country and world.
Seizures can be caused by withdrawal from some medications or drugs, the most common being alcohol.
After being diagnosed with Epileps I have done a lot of research especially with siezures in Women, there is a disorder that mimics Epilepsy but it is what they call psychological. Even though it is a strange phenomena in people with a lot of stress and or unconcious termoil can cause people ti inadvertantly have what is called a "pseudo siezure" The physical look of these siezures are real, just not the neurological aspect of these siezures, there is an awesome website about this: http://www.pni.org/neuropsychiatry/seizures/epilepsy/pseudo_seizure.html
I hope this may help you out
Hi, I had the same test done as your sister did. I had mine done in Chicago. I was up there for 3 days and they couldn't find anything then they decided to add more leads and take me a lil of my meds. Has your sister or ever thought about that? If so, the doctor that I go to, his number is (773)-834-4702. If you need anymore info, you can e-mail me at ***@**** I hope your sister gets better.