I did a googlle and I see Tennesse has Vanderbelt and University Tenn medical hospitals. 'USUALLY' these larger neuro clinics will have sub-clinics with movement disorrder specialist, maybe not nessecarly Ataxia Specialist.
From your post mentioning the 'cell atrophy' I am presuming you have have mri and seen doctors. They should be able to help you and do referal for you, even your primary should be able to help.
Does your local hospital have a resource office? That may be somewhere to look also.
Oh, I just googled and looks like you have the University there.
And the UT Medical Group.
It is common to have to travel a good distance to see doctors that specialize.
I hope this helps somewhat.
If you want to give a little more back ground that would be great.
Take care, Amo