I don't know that it's been defined, Heather. But in MY mind - a wobbler would be one that has the slight shaky back and forth movement, or tilted head - basically, mild degrees of the condition.
A spinner to me would be the "train-wrecks". The ones that twist and contort their bodies with no control, unable to right themselves, etc.
Others may define it differently - but that's how I think of them in my mind.
Hope that's the sort of answer you were looking for!
I agree although spinning can be less severe with constant corkscrew like behavior.