Ellen,
I had surgery in 2005 to remove AN from left side. Three years down the road and I ended up using a cane as I my balance was becoming worse with time. I did have vestibular therapy right after surgery to regain my balance, this worked well for short period of time. They measured me at 85%. My most recent diagnosis in 2008, was labyrinthitis where inflammation of inner ear and hemhorrage of cochlea were found on yearly MRI. I underwent labyrinthectomy through the ear canal as I was deaf anyway (this approach plus gentamycin will destroy any serviceable hearing). After removal of semicircular canals, cochlea and residual vestibular nerves I am so much better! I was awake for this procedure, no pain as they did a nerve block, and recovery time was nil. I did go back to vestibular therapy where my balance after this surgery measured 65%. I have regained 75% and expect more improvement with in-home exercises. I do not need my cane unless I walk in dim light/darkness. I would like to say to your mother that her tumor is causing a disruption of signal to the brain. The other (good) vestibular nerve is trying hard to compensate, but just can't until the damaged nerve is a dead one. I feel being deaf on one side is much better than experiencing the balance problems. The gentamycin approach might work, less risky than say surgery? Although wait and watch for small tumors is the way to go until they start to cause other symptoms. Perhaps vestibular rehab is in order so she can speed up the better balance and lessen the nausea she must be experiencing. Some people go into vestibular rehab before anything is done to treat their AN's as their balance is terrible and this can help some, perhaps she can look into this? Tell her there is someone that does understand how awful is feels, as I've been there.