Mine had seizure type spells also. A br, I named her Rye!
I did vitamins and I even tried a course of antibiotics but it wasn't until I gave her an injection of vit B12 into her breast that I seen tremendous improvement. That was in December and I gave her another one in January. She has been almost perfect ever since. She seems to look at you a bit sideways, but I can live with that. Knock on wood, I hope that was her cure.
When she was in bad shape, it seemed hopeless. If you have a bit more energy, hang in there a bit longer. It takes time. I thought it was some sort of a defect too, but low and behold, all this stuff seemed to help.