I recently agreed to foster an 18 year old CH cat. I knew that she has cancer so my first reaction to her wobbly gait was that the cancer had spread to her brain. Fortunately this is not the case.
Apparently she has had this her entire life. She is a dear cat and has a HUGE personality. I can always tell when she goes from room to room because I can hear her falling down, but she always gets up and keeps going. The other cats just stay out of her way.