I've actually got ataxia but someone suggested mentioning this here which is probably a good idea.
Before Christmas someone mentioned to me a new book: B12 Deficiency and Chronic Illness by Mike Newman (it's only Kindle). It's a complicated story but she has CFS which she now believes is linked and that it also talks about symptoms including ataxia.
Without going into details, which are too complicated, it seems that most doctors are getting B12 deficiency all wrong and that all they are doing by raising blood levels is making the blood look normal but the nerve damage (and other stuff) is continuing - or it can already be permanent.
Although there is lots of interesting historical stuff in there, which tells you how the illness used to kill most people by nerve damage rather than anaemia, it also gives lots of new stuff. This includes the fact that ALS International are recommending to their patients (and have done for several years) that methylcobalamin is injected in massive amounts on a daily basis. In the UK we call ALS motor neurone. This, apparently, is extending the lives of some of the patients by up to 2 years.
There is also lots of other stuff talking about symptoms, gut disorders and other deficiencies but much of the information it says was known a long time ago - and it's just that doctors now have lost the information.
If you think it might help you then take a peek - also, if you know anyone with ALS then point them in that direction. For those who don't know this is a terminal condition and anything which will extend the lifespan of patients must be a blessing.