When shopping for cell phones for seniors, one of the most important factors to consider is hearing aid compatibility (HAC). Many mobile phones create interference with listening devices that can create feedback, humming noises or static or make it difficult to hear in general. Each major cell phone plan provider is required to offer hearing aid comaptible cell phones which are often clearly marked as such. However, if they are not, you can tell how well a cellular phone will work with a hearing aid by understanding M-ratings and T-ratings.
Microphone Rating vs. Telecoil Rating for Cell Phones
Most modern hearing aids come with two modes: acoustic coupling (microphone mode) and telecoil coupling (inductive mode). While the acoustic coupling picks up all sounds, including ambient noise, telecoil coupling is designed to pick up only electronic signals sent by a phone. Some listening devices automatically disable the acoustic coupling and uses only a telecoil coupling when it’s placed near a phone to prevent feedback. Meanwhile, some smaller aids will only use the acoustic coupling because they do not have a built-in telecoil coupling.
Because there are two different modes for listening devices, phone manufacturers are required to disclose ratings for both. These are referred to as M-rating (for acoustic couplings, or microphone mode) and T-rating (for telecoil coupling).
The scale for both ratings ranges from 1 to 4, with 1 being the worst and 4 being the best. The ratings are broken down as follows:
- M1 or T1 – Poor
- M2 or T2 – Fair
- M3 or T3 – Good
- M4 or T4 – Excellent
M and T ratings are not necessarily correlated. So, for example, a phone may have a M3 rating and a T3 rating or a M2 rating and a T4 rating.
Ideally, you want to choose a phone with an M-rating of M3 or M4 and T-rating of T3 or T4.
Hearing Aid Ratings
Hearing aids also have varying levels of radio frequency (RF) interference resistance. This is to prevent your hearing aids from unintentionally picking up radio signals, but this can also affect their compatibility with mobile handsets.
Because of this, it’s important to factor in your hearing aid’s M-rating and T-rating when considering cell phones for seniors. Not all manufacturers list these ratings, but you can ask your audiologist to find this information for you.
To find your combined rating, simply add the phone’s M-rating or T-rating with your hearing aid’s M-rating or T-rating. The higher the number, the better. The breakdown looks like this:
- Combined Rating of M4 or T4 – Usable, but not ideal.
- Combined Rating of M5 or T5 – Acceptable
- Combined Rating of M6 or T6 – Excellent
So, for example, if your mobile phone is M3 and T3 and your hearing aid is M2 and T3, you would have combined ratings would be M5 and T6, which is good.
Federal Communications Commission (FCC) Mandates
The FCC has enacted laws in the U.S. that define hearing aid compatibility (HAC) and set rules for how many HAC handsets each nationwide carrier must offer. In order to be deemed HAC, a phone must have a rating of M3 and T3 or higher. Furthermore, retailers must allow you to test handsets for HAC before purchasing. Cell phone companies are also required to include details about HAC on their websites.
While the M-rating and T-rating are good metrics for determining HAC, there are other factors that affect how well a cell phone might work with a hearing aid. For example, cell phones from CDMA carriers – such as Verizon Wireless and Nextel/Sprint – tend to work better with hearing aids than GSM cell phones, such as those provided by AT&T and T-Mobile. Also, flip phones and clamshell designs tend to provide less interference than other styles of cell phones. The FCC also states that placing the phone slightly behind the ear rather than directly over the ear may actually provide a better signal.