The whole industry is going to be blown wide open in the US very soon. There's a bill going through to allow over-the-counter hearing aid sales rather than having to visit and audiologist.

http://hearinghealthmatters.org/hearingnewswatch/2017/otc-he...

Up till now a "hearing aid" is classed as a medical device and requires a trained medical professional to fit it.

Everyone and their dog will be getting in on the act now.