And hearing-aids are only partial solutions -- I know relatives with them who still have problems hearing, especially in crowds. And the hearing aids don't prevent further decline, they only work with the hearing that is there.
http://www.abelard.org/hear/hear.htm#questionOctober 3, 1997: NY Times
Midlife is catching up with Bill Clinton: Doctors fitted the baby-boom president with hearing aids on Friday. Clinton, who turned 51 in August, has complained for years about hearing loss, listing it as a problem in his annual physicals since his days as Arkansas’ governor.
He found it had worsened this year and reported having trouble hearing people in crowded receptions. Presidential press secretary McCurry said “ indeed, he often can’t make out what hecklers occasionally shout at him while he is making speeches...”
For what doctors termed a high-frequency hearing loss in both ears, Clinton was fitted for the type of hearing aid that can be easily placed fully inside his hearing canal, hardly noticeable to other people.
The president’s problem, a moderate difficulty hearing high-frequency sounds, is typical of hearing loss due to ageing and exposure to loud noise