Difficulty In Hearing Loud Noises, No Improvement With Hearing Aids. Is It Curable With Surgery?

Hello Doctor, My sister has hearing problem. She cannot hear loud sounds. She can hear, if a person speaks normally or moderately. She has been experiencing it from Xth standard. Now, she is pursuing graduation. She could hear the voice properly many a times of the person, whom she knows and talk frequently. She tried with hearing aids , but, she felt that, she could hear more clearly without it. Kindly help. Is there any surgery for it. Tell us, if you know some good ENT specialists in Bangalore, India for diagnosing it.