Please get her checked by her doctor if you feel something is definitely wrong.
But I want to mention that I was wondering the same about my son as well around that age. If I called him from the kitchen and he was in the living room, he wouldn't turn and look at M.. It happened many times at that age. He would be with a nanny at home and he wouldn't hear M. come in or talk to him until I went into the room and he almost saw M.. He responded well otherwise when he knew we were talking to him or other sounds at home(TV, phone etc).
He was fine though. Maybe it was just that he was too distracted to hear M. calling him. I didn't get him checked. If you are confused , maybe you can monitor her hearing for a few days before seeing the doctor. Try talking to her from a short distance and see if he responds.Then go further and further everyday. Sometimes babies that little don't care if their name is being called, So maybe make some other noises as well and see if that gets her attention.