I am suffering from unexplained vertigo, and no health specialist has been able to find the cause. Any Ideas?

I understand that no one here can give me a diagnosis but what I am looking for is maybe something the specialists have not thought of. I have been through many tests, MRIs, CAT Scans, had my optic nerves thoroughly checked out, all blood tests came back normal and so forth. So far the best guess given by specialists is that I suffered brain damage caused by a virus and I just have to wait until my brain rewires itself, but even the specialists agree that that they cannot be certain about this, It starts with a general light-headedness followed by a loss of balance. It fells like I am on a boat or a water bed. It is not positional vertigo, that was ruled out early.