I've never had a seisure dog, but have friends that have.
It can sometimes be a struggle finding the right meds, and level of those meds, but once found they can live normal lives as long as they are on the meds.
Also sometimes things such as Heartguard, Frontline, etc. can cause them.
Some people will start keeping a diary of what they have been feeding, what meds given when and when the seisures happen to find out it there is something triggering them.