High-end hearing aids already do this on-device. I don't think it would be a great development to require hearing aid owners to own a smart phone and load an ap

High-end hearing aids already do this on-device. I don't think it would be a great development to require hearing aid owners to own a smart phone and load an app onto it to be able to get full functionality out of their hearing aids. If the functionality needs to be externally configurable for some reason, provide an external controller that comes with the hearing aids.