Hearing aids have not in the past always worked effectively with cellular phones, because of electronic interference between the 2 devices that caused static, whizzing or squealing noises, or dropped words. Technology enhancements along with new regulations have mostly eliminated this problem. Nowadays cell phone – hearing aid compatibility isn’t the challenge it used to be. To help consumers shop for the right hearing aid compatible cell phone, the new regulations include a standard rating system and labeling requirement.
To understand how this rating system works, you should first understand the two modes that hearing aids work in – M mode (for microphone) and T mode (for telecoil). In M mode, your hearing aid uses its built-in microphone to pick up audible sounds from the environment and amplify them so that you can hear them. In T mode, the hearing aid instead uses an inductive process to pick up electromagnetic signals inside the phone directly, without the need for a microphone. The T mode is important when shopping for a phone, because at least 60% of hearing aids sold in the US have one.
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). To be labeled as hearing aid compatible (HAC) a mobile phone must carry a minimum rating of M3 or T3.
Hearing aids and cochlear implants have a similar M and T rating system to certify how sensitive they are in each mode, and how resistant they are to radio frequency interference. When shopping for a phone, to determine its compatibility with your hearing aid, simply add its M and T ratings together with those of the phone to create a combined rating. A sum of 6 or more makes a solid pairing. That hearing aid and mobile phone combination should work well for you. 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.
This combined rating system makes it easy to shop for a mobile phone online, because it easily allows you to determine how compatible it will be with your hearing aid. If you are able to shop in a store that allows you to “try before you buy” and actually use the phone you want while wearing your hearing aid, that is of course a better idea.