Farmerswife, judging by your mapdot, you're not far from Iowa City.  I think if I were in your situation, one thing I would try would be an appt with Dr. T.F. Viner.....his office is out on Hwy 1 near Steindler Clinic.  He is an ENT specialist, and has been a huge help to several members of our extended family over the years.  To me, it would be worth it to see what he has to say.  FWIW.   I sure hope you get some answers.......that has to be terribly frustrating.