The guy we need here hasn't been on the forums for a while. Scott, "Rockstar_NOT) works in auditory science in some capacity and knows a great deal about this very subject.

Wife 3.0 wore very expensive hearing aids but they were proof that "expensive" and "high quality" are not the same thing. All they did was feed back. I don't know why hearing aid manufacturers make them in a way that the signal that the batteries are running low is a high pitched tone that the hearing impaired person can't hear. Wouldn't a series of gently vibrating pulses be more effective? Or maybe have them come out of the ear and fly around like that little ball in Harry Potter.