EVOLUTION of Hearing Aids
![Courtesy of Oticon Courtesy of Oticon](https://www.chha-nsb.com/wp-content/uploads/2019/08/Evolution-of-hearing-aids.jpg)
Courtesy of Oticon
Also read the following article by Neil Baumann:
http://hearingaidmuseum.com/resources/The%20Hearing%20Aids%20of%20Yesteryear.pdf
Look in The Hearing Aid Museum to see how far we have come: http://hearingaidmuseum.com/