The Cellphone and the Hearing Aid: The Odd Couple
Cellphones and hearing aids aren't always compatible in close proximity, but
   they're starting to get along 
From: IEEE Spectrum Online - 01/2009
By: Joseph J. Morrissey

Today the aging of the population means that more people are suffering from
hearing loss. In fact, 4 million to 6 million people in the US currently use
hearing aids. Even more need them but don’t wear them, although a greater
proportion of this population is likely to start using hearing aids as they
get both more effective and more attractive. 

At the same time, there are over 280 million cellphone subscriptions in the
US, for cellphones are rapidly becoming a ubiquitous and essential form of
communication in today’s global society. 

It's a given that a growing number of hearing-aid users are cellphone users
as well. But like The Odd Couple’s Felix Unger and Oscar Madison, these two
fundamentally good technologies cannot always live together in close
proximity without conflict. At issue is electromagnetic compatibility. 

Read the entire article at:
http://www.spectrum.ieee.org/jan09/7187

Links:
ANSI ASC C63
http://www.c63.org/

Hearing Aids and Cell Phones - FDA
http://www.fda.gov/cdrh/wireless/health-hearing.html

Hearing Aid Compatibility and Volume Control
http://www.fcc.gov/Bureaus/Common_Carrier/FAQ/fwaq_hac.html