My spider has a pretty severe wobble herself, it gets a lot worse with stress and almost looks like a seizure, like you were saying. Once she acclimated to her new home, it got much less noticeable. Now, it's mostly just a slight wobble of the head. She eats great, and does all her normal snake things so I don't think she's bothered by it too much. I've heard they can grow out of it, but I'm not sure if that's correct or not. Beautiful spider, by the way!