I had GK and for 4 months after that was progressing well. Then out of the blue, I began to lose my balance again. Since then, Jan 2013, I have had headaches, a lot of balance issues and loads of physiotherapy. That identified a very specific area of balance - if I looked in the direction of 12 - 3 on a clock face in front of me, I fell. I had to stop driving, gave up work as it was quite impossible and worked on the balance.
Now it's a lot better. Still can't drive, but my balance is pretty good, as long as I'm in usual places, keep working on the exercises and don't have a bug. If I do, or if I go somewhere with a lot of visual challenges, like hills and corners Tec, my balance can't cope.
I fell a couple of weeks ago - in a usual place, no bug, but I had turned, quite slowly, to cross a sloping surface and it was too much for my visual system to cope with, so down I went. What I can't do any more is correct myself if I start to fall...quite bizarre really, so there I was flat out!
One other thing has been nerves jumping in my neck and face on the tumour side. It dies down then starts up again a few weeks later. I'm hoping that as the tumour continues to shrink, its effects on the nerves will settle, but it's still changing. This may chime with others experiences.....or not.