Multi System Neuronal Degeneration in Cocker Spaniels

The internet is a wonderful tool, but I tried to find out why our Cocker Spaniel has occassional times where his teeth chatter and his muscle twitches, all the while conscious, but he acts like he doesn't know what is going on and being a nurse thought had to be some kind of seizure. We found an article by "Dog Owner's Home Vet. Handbook", sudden inexplicable short bouts of teeth chattering could be a sign of focal motor seizures also called partial seizures. It went on to say the dog stays conscious and part of the goes into spasms.

Additionally, found information referring to the phenomenon as Multi System Neuronal Degeneration, usually hereditary in nature. Some of the information was confusing in the sense that said that it was found to be in red colored Cocker Spaniels, but can be found in others, because Toby is basically white, with a hint of "buff". The really disturbing aspect is that it can only be diagnosed post mortum.

While researching this I discovered another affliction for white hair colored dogs, called "White Dog Shaker Syndrome".

I was wondering if anyone knew anymore about either; it is quite concerning seeing him experience this and powerless to help.
Dog Owner's Home Veterinary Handbook