Hearing aids and cellular phones have not always gotten along as well as they do now. The intricate electronics in both products often triggered static, dropped words or squealing interference noises. Thankfully, improvements in technology and new government regulations have made the question “Will this phone work with my hearing aid?” easier to answer. The regulations mandated new labeling requirements and ratings that help you to easily find a cell phone that works well 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. Roughly 60 percent of all cell phones sold in the United States have a telecoil (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). To be sold in the United States as hearing aid compatible (HAC), a mobile phone or cordless handset must have a rating of at least 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. To determine the compatibility between your hearing aid and a mobile phone you are considering, just add the M and T ratings together; add the M rating of the hearing aid to the M rating of the phone and add the T rating of the hearing aid to the T rating of the phone. A combined rating of 6 or more is considered excellent, a hearing aid/phone combination that would provide highly usable, interference-free performance. A sum of 5 is considered normal and should work fine for typical cell phone users. 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.