Acoustic Neuroma

My mother was diagnosed with acoustic neuroma in 2002.  She underwent the Gamma Knife.  Her tumor never shrunk, but her symptoms have not got any worse and her balance did improve.  In April, she noticed that the traffic stopping and starting was bothering her.  She can no longer drive in big cities with a lot of traffic.  She also has one spot on her face that is numb.  She won't go back to get another MRI until August because of her insurance.  I am going crazy because she has never had facial numbness before.  She has had motion problems.  Has anyone else had symptoms like these?