My 75-year Old Mother Is Suffering From A Feeling Of

My 75-year old mother is suffering from a feeling of Rockiness (off balance) for the past several months. She has bad allergies and having taking meds and been to a primary, cardiologist, ENT...you name it an no one can tell her what it is. It's not vertigo as she has it constantly not just upon rising or laying down. Can anyone help point us in A direction. We're scheduled to see a neurologists soon. Primary did a CT scan and it was normal.