In the past, the sophisticated electronics of cell phones often interacted badly with the electronics of hearing aids, causing interference between the two devices that was perceived as static, squealing or whistling noises, or lost words. Thankfully, improvements in technology and new government regulations have made the issue “Will this cell phone work together with my hearing aid?” simpler to answer. The labeling requirements mandated by the new government regulations make it easy to find a mobile phone that is compatible with your hearing aid.
The first thing you need to understand is that hearing aids operate in two different modes – microphone or “M” mode, and telecoil or “T” mode. In M mode, the hearing aid uses the internal microphone to detect sounds and amplify them. In T mode, the hearing aid uses telecoil technology instead. The hearing aid is able to pick up the electromagnetic signals from inside the phone directly. Currently, approximately 60% of hearing aids sold in the U.S. have a telecoil or T mode.
The rating system for these two modes of hearing aid operation uses a scale that ranges from the lowest sensitivity (1) to the highest sensitivity (4). No mobile phone or cordless handset sold in the United States can be sold as hearing aid compatible (HAC) unless it has a rating of at least M3 or T3.
Hearing aids themselves also carry M and T ratings to indicate their sensitivity and ability to block interference in each mode. If you know the M and T ratings for your hearing aid, to determine its compatibility with any mobile phone, just add the two sets of ratings together. If you get a combined total of 6 or more, that is thought of as excellent, a combination of hearing aid and phone that will be highly usable. A combined rating of 5 is thought of as normal, and suitable for most people. A sum of 4 is considered acceptable, but if you are a heavy mobile phone user, you may be disappointed or frustrated with this choice.
If you are shopping for a mobile phone online, you can usually use this combined rating to determine how compatible the phone you are interested in buying will be with your hearing aid. A better approach, of course, would be to go to a store that allows you to “try before you buy,” and actually use the phone you want while wearing your hearing aid, in both M and T modes.