In my never ending search for answers I came across this study today:
CoQ10 and Spinocerebellar Ataxias
For those that want the "Cliff Notes" version here it is . . . CoQ10 showed some minor benefit in reducing symptoms especially in patients with SCA3, but it did not seem to impact disease progression. This was not a clinical trial; it was a study of patients who reported taking CoQ10 on their own.
As always, do NOT take something based on an internet post. Talk to your doctor if you'd like to consider trying this!