I am b12 def & have hypothyroidism. been having extreme neuro symtoms for 6 mos that dr says aren't neuro. could b12 & thyroid cause symptoms?

Yes: This is hard to answer definitively without knowing more details of your symptoms, but B12 deficiency can cause a wide range of neurological symptoms & hypothyroidism can cause some. See http://chriskresser.Com/b12-deficiency-a-silent-epidemic-with-serious-consequences and the book could it be b12? For a long list of hypothyroid symptoms see http://www.Stopthethyroidmadness.Com/long-and-pathetic/.