Links about hearing loss prevalence (also in younger generations) and hearing aid myths:
https://www.tuck.com/hearing-loss-and-sleep
http://www.betterhearing.org/hearingpedia/prevalence-hearing-loss
http://www.asha.org/public/hearing/hearing-aid-myths-and-facts
http://www.hear-it.org/1-out-of-6-baby-boomers-and-1-out-of-14-Generation-Xers-have-hearing-problems
http://www.betterhearing.net/blog_baby_boomers.php
Links about how the ear works and causes of hearing loss:
www.asha.org/public/hearing/how-we-hear
https://medlineplus.gov/ency/article/003044.htm
www.hearingloss.org/content/basic-facts-about-hearing-loss
Links about hearing aids:
http://www.mayoclinic.org/diseases-conditions/hearing-loss/in-depth/hearing-aids/art-20044116
http://www.oticon.co.za/hearing/getting-help/hearing-aids/hearing-aid-technology.aspx
https://www.bestsound-technology.co.za/siemens-hearing-aids/