I had single session Cyberknife which for all intensive purposes is very similar to GK.
The worst symptoms that I had was in the first 2 weeks.
All the problems I had pre treatment got worse.
Tinnitus was like a rock concert at times fortunately only for a few hours at a time, hearing deteriorated, and balance was pretty darn average too. Memory fog.. had that before treatment, and it got worse after treatment
Hang in there, things did get better, a lot better.
I had symptoms in cycles, with alternating tinnitus, hearing loss, balance issues.
With each cycle the symptoms reduced, and the time between the cycles increased.
At 4 1/2 months after improving heaps, concentration went downhill, and nausea dizziness increased.
Took a holiday for 2 weeks and felt much better for it.
I had increasing symptoms at 4.5 months and 8 months and 11 months
At 18 months I am still improving, I feel far better today than I did pre treatment.
At 16 months the cloud lifted and has not been back since.
Hearing has improved from needing a hearing aid pre treatment to not needing one now.
All of these things may sound worse than they really were..
The symptoms were annoying, not debilitating.
More like living in a permananent mild hangover, with an ear plug in one ear.
That has been my expereince.
Hopefully all your experiences will be positive too.
At 18 Months I feel great.
Happy Healing