Michael,
My mom was having the dizziness problem several weeks after her treatments ended, and she was finally sent to an ear specialist with her oncology group. She had fluid built up in both ears which could not drain properly due to the radiation affecting the eustacian tubes. The doctor put tubes in to drain mom's ears and she got almost immediate relief from the ear pain and pressure. The dizziness improved significantly, though she may have some remaining problems due to the cisplatin. She is much improved now, though, as it has been about a month since this procedure was done.

Hope this helps you.

Laura