Hi Beverly and welcome to this forum .....
I can appreciate your concerns related to being a musician.
At the time of my diagnosis, I was a church organist of long-standing, as well as a singer. The first symptoms of my AN were off balance/disoriented feelings ..... no hearing difficulties. I was not properly diagnosed until about a year and a half later, when I began to have that "stuffed ear" feeling. An audiogram revealed a 20% hearing loss in my left ear, but I still had 100% speech discrimination. The MRI with contrast showed a 2+ cm AN, already outside the internal auditory canal, approaching the brain stem. Because of the size, my diagnosing ENT thought I should be a candidate for either radiation or surgical removal. However, when they took my history, and found out I had had massive doses of "radium" to my head as a child, radiation treatment was taken off the table as a possibility.
So, in responding to your concerns, I have had no experience with radiation treatment for my AN. Hopefully someone else will reply here as to their experience as a musician with radiation treatment and/or possible hearing loss from it.
In my case, I have an Oticon Medical Ponto Pro hearing device. The abutment was put in at the time of my second surgery three years ago. My hearing loss came in stages ..... from 100% pre-diagnosis, to 80% pre-first surgery, to 20% post-first surgery, to 0% post-second surgery so my brain had several adaptations to make. Remember, hearing is actually a "brain thing." The ear is just the receiver of information/sounds. I have a wonderful audiologist who explained all of this to me.
How this affected my musical performance ..... After the first surgery, I was initially very frustrated. Everything sounded out of tune. Prior to that first surgery I had "perfect pitch." It has never returned. It took probably over a year before my brain finally realized it needed to sort out these lesser sounds coming from the AN side. I successfully sang in choirs, but I worked with the directors to position my placement to best advantage. Unfortunately following the second surgery, I have not been able to sing in a group, but not because of my hearing. There is a weakness of my left vocal cord that has caused me to have little stamina for singing for any length of time. However, because of my Ponto (bone-anchored hearing device) I am still able to play the organ/piano. Again, it took my brain awhile to adjust to hearing the sounds from the Ponto, mixed with my natural, good hearing from my non-AN side ear.
Sorry to be so long-winded when my situation is not the same as yours, but I hope you can take what applies to you.
Let me know if you have other thoughts/concerns.
Thoughts and prayers. Clarice