Hi Tbanis2463 .....
I did not have radiation for my AN, so I am not much help on hearing issues post-Gamma Knife. Just wanted to welcome you to this forum and hopefully others will contribute their thoughts to your questions.
I will say this about hearing aids ..... as you probably already know, they are very expensive and most insurance companies will not pay anything (or at the least, very little) for them. After my first surgery, I still retained 20% of my hearing, with 100% speech discrimination so six months after surgery I was fitted with my first one, a MicroTech7 ..... with only fair satisfaction. Long story but I got a second one less than a year later ..... different audiologist, who fitted me with a WidexMind, which was a big improvement. Alas, two years later my tumor grew back and after the second surgery I am deaf in my AN ear now. So, I have $6,000 worth of two perfectly good hearing aids sitting in a box on my dresser.
Not to worry though because I have a bone-anchored Oticon Medical Ponto Pro now that I love. I rarely think about being single-side deaf anymore.
As for the tinnitus ..... that's another matter!!
Clarice