luckylady
(1) Sorry had my surgery in Los Angeles.
(2) The ABR test is another hearing test, except that they will attach some electrodes to your face and scalp and take some measurements as you listen to the tones, some hissing and clicking. They will probably do it as part of the other pre-op hearing tests. All the tests kind of blend together. I don't remember anything unusual about it.
(3) Re: Your hair. Need to ask your neurosurgeron. At the St Vincent's (in Los Angeles), my doctor only shaved a 2-inch wide strip along the incision line (side of my head). I have short hair about 2-3 inches long (I'm a male). When I went home about 10 days after surgery, no one could really tell because the incision blended into where I part my hair (side comb). If I had to do it over again, I probably would have gotten a crew cut, because my scalp was so itchy as the incision healed. One thing to consider, you aren't allowed to get the area wet for about 6-7 days. There was one lady in the hospital at the same time, and she kept her shoulder length hair. It was a little awkward rigth after surgery (with the bandage) but I think she was happy to keep her hair.