Dogs that grow an inordinate mass of hair in an ear can become more easily coated with some wax and dirt, dust, etc., which could diminish hearing, especially if the dog already had some hearing or tonal problems but more than likely, any hearing problems are related to the ear itself or the dog's tuning out things she prefers to ignore.
If the vet can find no hearing or ear problems, start her on a good, regular obedience training program where she's encouraged to have fun learning and excited to do what you ask and will come running every time you call or get up to do anything just because she's eager to engage with you. Enrich her life with interesting puzzles-for-treats and games you teach her to play and fun outdoors activities with you and she will want to be with you and will no doubt hear you every time.
__________________  Jeanie and Tibbe One must do the best one can. You may get some marks for a very imperfect answer: you will certainly get none for leaving the question alone. C. S. Lewis |