ReSound LiNX, Beltone First and the Starkey Halo are hearing aids that work directly with iPhones. Audio is sent to the device as it would a Bluetooth earpiece. It can also act as a remote control.
One’s phone can be a hearing aid’s microphone, record information about when and where it is adjusted, and track how often it’s used. An audiologist can use this information to manage the device’s settings. Lost hearing aids can be located via GPS.