In the past, the complex electronics of mobile 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 missing words. Technology enhancements along with new regulations have mostly eliminated this issue. Today cell phone – hearing aid compatibility isn’t the huge problem it once was. To help consumers shop for the right hearing aid compatible cell phone, the new regulations include a standard rating system and labeling requirement.
Understanding the rating system requires a bit of knowledge about the modes that hearing aids can operate in. There is an M mode (which stands for microphone) and a T mode (which stands 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. When the hearing aid is in T mode, instead of the microphone it uses its built-in telecoil to directly pick up conversations from inside the phone, in the form of electromagnetic signals. The T mode is important when shopping for a phone, because at least 60% of hearing aids sold in the U.S. have one.
Under the new regulations, these two modes of operation have ratings that range from 1 (the lowest sensitivity) to 4 (the highest sensitivity). To be labeled as hearing aid compatible (HAC) a cell phone must carry a minimum rating of M3 or T3.
In addition, many hearing aids (and cochlear implants) have a similar M and T rating to measure their sensitivity and their resistance to radio frequency interference. 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. If the combined rating is 5, this combination is considered normal and suitable for most regular phone use. A combined rating of 4 is considered usable for brief calls, but may not be suitable for extended phone use.
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. 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.