Dear Pat,
I know what you are going through. I had a similar problem with my yorkie, Ringo who also suffered from late onset hydrocephalus (normal until 5 years old) with personality change and seizures about every 6 weeks.
Here's what helped him. Prednilizone shots once a month.
Contant monitoring of phenobarbitol blood levels. (Pheno twice a day)
Also, whenever he got some valium he seemed more pain-free (I assume it feels like a headache). He was relaxed and more of his old self.
If I could do his treatment over again I would beg, borrow and steal valium for the little guy. (Even the best Vets are hesitant to give valium as they assume the human will take it and so I never pushed the subject.)
I don't usually check forums but you can email me directly if you would like to know more.
lydjoseph@hotmail.com