neurological issues

Hello,

I have an older normal corn roughly 10 to 15 years old that has suddenly with in the last few months developed neurological issues. Around 4 or so months ago he started having issues with corkscrewing and maintaining an orientation. Slowly he has stopped eating and I am considering euthanizing him at this point as I dont know what else to do. In terms of husbandry his temps or normal, with a cool side of high 60s and a hot spot of roughly 85, and dont know hat could have caused it except either it just being a natural health issue or if something was wrong with his most recent aspen bedding . Has anyone else ever had similar issues?