Trust Your Hearing to Over 69 Years of Knowledge & Experience! We are the oldest & largest hearing aid provider in Montana. Hearing Aid Institute has been available to serve the community since 1944. We are part of the All American network serving people at over 300 locations throughout the United States. The All American hearing network has set the standard of excellence for the patient journey in hearing health care. Our mission is driven by the needs of our patients and our commitment to listen and serve them.