I had experienced ataxia of sorts and after a couple of bouts of paralysis and other muscle and nerve issues was finally, after twelve years of symptoms, diagnosed with Celiac Disease. I did not experience GI issues and many doctors are unaware that there are over 200 symptoms of Celiac (other than GI), so it often goes untested for. I also experienced the need to frequently swallow when my thyroid gland was enlarged, which can also happen with Celiac. I did ask for an ultrasound. If you haven't already been screened for Celiac and/or thyroid issues, perhaps that could be worth investigating?