my grandmother started prednisone the day after the fourth of jul...

my grandmother started prednisone the day after the fourth of july and that Sunday in the car she thought the radio was on, but when she went to turn it off it was off, she hears joy to the world all the time. Sometimes its louder than others but its always there. She started out on 40 mg a day for polymyalgia, now she is being tapered off of it but her doctor says shes not a typical patient and there is no way the prednisone triggered it. I think it has to be it cause it happened about three days after she started taking it. Anyone know anything about this kinda thing happening?******