That should be interesting.
Hm. I'm not sure about wisdom damage, that also means they don't see and hear as well. Charisma damage, instead? Maybe a rage effect when it's reduced to 0 or 1?
I'm mentioning this because, like you, I remember one story where various dogs, cats, cows, etc. would go wild when brought near the Draugr's grave and that this was usually the first sign by which they were recognized.