Often patients ask me how one hearing aid is communicating with it opposite hearing aid. I figured I would combine my general knowledge as an audiologist with a little extra research to fully answer the question about what technologies are used for wireless communication in hearing aids.
So how do hearing aids communicate with each other? Hearing aids have wireless chips that enable short-range communication. There are 3 types of wireless chips known as NFMI, 900mHZ, and 2.4gHz. These technologies enable hearing aids to sync volume changes, stream phone calls between ear, provide background noise reduction, and allows stronger directional microphones.
Phonak, Unitron, Oticon, Widex, and Sivantos hearing aids use near-field magnetic induction (NFMI) for their wireless communication between hearing aids. Starkey uses 900mHz and Resound uses 2.4gHz. However, any specific hearing aid may use more than one wireless technology.
That answer was pretty technical and I hope to help you understand what the benefits and disadvantages of each of the systems are.
Why Having A Wireless Hearing Aids is Essential
The potential of a hearing aid is greatly enhanced by having a wireless chip in it. A wireless chip enables a hearing aid to make a team decision with the hearing aid being worn on the opposite ear as well as communicate with other accessory devices such as remote microphones, Bluetooth phone adapters, TV connectors, and remote control devices.
Almost all advances in hearing aids in the past 10 years have been because a hearing aid can communicate between ears. Back in my undergrad days in 2007 hearing aids could sync volume control changes between ears thus saving a person from having to hit a button on the opposite hearing aid.
Today, hearing aids not only sync the volume but analyzed exactly from what direction a noise is coming from so that they can steer directional microphones to reduce background noise.
As well as recognize when a phone call is coming into the microphones of one hearing aid and transfer the sound signal to the opposite ear thus making phone calls easier to understand by being heard in both ears.
Hearing aids can also pick up when the wind is blowing on the microphones on one hearing aid and cut that sound off but allow the person to keep hearing by streaming the opposite hearing aids signal to both ears.
These advances in technology are only samples of the changes made to improve the quality of hearing aids in the last 10 years that have all been made possible by wireless communication chips in the hearing aids.
Understanding Hearing Aid Wireless Communications
There are 3 main choices of wireless chips that hearing aid manufacturers choose to use: near-field magnetic induction, 900mHz, and 2.4gHz.
These technologies are not proprietary to any one manufacturer so they can each use them if so desired. Hearing aid companies have to make decisions on the pros/con of each of them in order to make their desired product.
Here are some quick facts about each technology.
Near-field Magnetic Induction (NFMI)
- Used by the most manufacturers
- Fast data transition for a large amount of data
- Works within a 2-foot range
- Hearing aids can be in constant communication with each other
- Requires intermediate device for Bluetooth cell phone calls or TV streaming (something has to hang around the neck or clip to a person’s shirt.
900mHz Wireless Chip
- Use by only Starkey hearing instruments.
- Same technology as a traditional cordless phone.
- Can transmit data up to about 50 feet away.
- Can transfer some data from ear to ear but not as much as NFMI due to head shadow effect.
- Great for TV accessories but bad for Bluetooth phone as the phone still requires an intermediate device.
2.4gHz Wireless Chip
- Use as Resounds only wireless chip. However, Starkey, Oticon, Phonak, and Sivantos also use this chip in their newest hearing aids.
- Same signal as Bluetooth phones use. Commutates directly to an iPhone/iPad or high-level android phones.
- Great for streaming a TV signal
- ONLY CAN TRANSMITS SMALL AMOUNTS OF DATA BETWEEN EARS due to head shadow effect.
The Future Is Bn NFMI and 2.4gHz Combined Into One Heairng Aid
Each of the technologies has advantages and disadvantages in them. To get the best of both worlds hearing aid manufacturers have now put two wireless chips in the hearing aids. NFMI gives you the best hearing aid features while 2.4gHz give you the best user experience with accessories and direct to iPhone capabilities.
When a user gets a hearing aid with both wireless chips there are really no drawbacks (except maybe battery life). Oticon Opn hearing aids were the first hearing aids on the market that introduced the dual wireless chips. These devices came out back in 2016 and have since become one of the most popular hearing aids on the market.
Sivantos was next to upgrade their hearing aids with the NX line of products. It included a unique aspect as it uses the processing ability of the hearing aids to help with own voice sounding bad issues with the hearing aids (see more on why hearing aids make your own voice sound bad).
Phonak has recently released the Phonak Marvel line of hearing aids that also includes both wireless chips and introduced the first hearing aid that can pair to any Bluetooth phone without an intermediary device.
Starkey hearing aids were the only manufacturer to use 900mHz as their wireless signal. This did have many advantages but in 2018 the whole audiology and hearing aid world got together and collectively decided that they would all program hearing aids in the same was using a 2.4gHz signal. This means that soon every manufacturer will be using 2.4gHz and possible the addition of a second wireless chip as well.
As additional hearing aids are released, I expect them all to have both wireless chips in them or come out with a completely new and better wireless chip.
How do cros hearing aids work? Cros hearing aid uses NFMI wireless chip to stream the incoming microphones on one hearing aid directly to the other hearing aid. Cros aids are used by individuals who have no hearing on one ear but better hearing on the other and enables them to hear sounds from all directions.
Are wireless hearing aids safe with pacemakers?Wireless hearing aids from all 6 of the major hearing aid manufacturers are considered to be safe to use by people who have pacemakers. Nevertheless, as a legal caveat, you will always be instructed to check with your cardiologist.