Unexplained loss of balance

For the past two years I have been experiencing periods where I topple over.  There is no associated dizziness or vertigo.  Inner ear problems have been ruled out and my BP and blood tests  show normal.  In the past six months these episodes are lasting longer and occuring more frequently.  I have had all sorts of tests with no diagnosis.
Earlier I could get back up with no lingering effects.  Lately I will stumble for days after falling.  Can anyone offer any suggestions?

[Daniel M Prevedello, MD]

Dear Rockledge

The goal of this forum is not to establish diagnosis. You should discuss your signs and symptoms with your doctor.

[rockledge]

I've decided to forego yet another MRI test.  I suspect past sport injuries concusions are likely to be a factor.  I wonder if anyone else has similar symptoms and/or injuries.

[rockledge]

I understand that an online diagnosis would be inapropriated Doctor.  I was just wondering if anyone else here has experienced similar symptoms while having negative results from repeated tests.

I have the distinct feeling that repeating the tests I have already had including some which are rather invasive, is pretty much futile.