I'm sorry to hear about John's yet-to-be-diagnosed condition. It might be worth
asking if it might be Ménière's disease - see
http://en.wikipedia.org/wiki/M%C3%A9ni%C3%A8re%27s_disease as a friend of mine
had this and it took them over two years to work out finally what it was!
Fingers crossed that you sort this out soon
Hugs,
Jayne