In the modern world, we’ve come to rely on mobile phones, tablets and other wireless devices to keep us connected to our family, friends and workplace all day, every day. These devices use signals that are transmitted through the air via receiving points, ultimately delivering messages to the recipient without wires. This technology has changed many things in our daily lives and hearing aids are no exception.
Wireless technology allows two hearing aids to operate together as one complete system, instead of acting as two independent devices. The sound input to both hearing aids is shared and decisions about the digital sound processing are based on the combined information. For example, if one hearing aid is being triggered for directional mode, both hearing aids would likely switch into that mode at the same time. The data transfer rates for wireless hearing aids are measured in nanoseconds, which is much faster than human brain can detect. For the wearer, the adjustments are perceived in real time. Sound processing is therefore synchronized between the two hearing aids, thus improving sound quality for the wearer.
You were born with two ears for a reason. Binaural hearing equips us to locate the source of sound quickly because the brain analyzes timing and level differences that are received from each side of the head. Localization is one of the reasons your hearing care professional will recommend two hearing aids to compensate for hearing loss that affects both ears. Traditional hearing aids process sound independently, according to the hearing loss in each ear. This can cause the wearer difficulty in pinpointing the sources of sound because the timing and level differences are often lost. Wireless hearing aids address this problem by working together to compare timing and level differences for sounds received at the microphone of each device, thus preserving the natural localization cues our ears provide.
Wireless capability may also result in hearing aid features that improve convenience. Some wireless hearing aids may be set up so that when a user pushes a program button or changes the volume control on one hearing device, the change is automatically implemented on the other side. Another feature made possible by wireless communication is the selection of a program button in one hearing aid and a volume control in the other hearing aid of the matched set. This arrangement requires less space for buttons on each device and reduces the amount of required changes by half. When the volume or program needs to be adjusted, the user only needs to touch one hearing aid and be confident that the other hearing aid will change automatically to match.
Wireless hearing aids are often capable of wirelessly communicating with external devices as well as with each other. There are a variety of technologies that make this possible, the most common of which are electromagnetic fields, frequency modulation (FM) and Bluetooth.
Some of these technologies have been around awhile, like the use of electromagnetic fields that can be picked up by an antenna in your hearing aid called a telecoil. With the advancements in wireless hearing aids, telecoil can be used to a greater advantage. A telecoil in a wireless hearing aid may be able to pick up the signal from a phone that’s placed near one hearing aid and then stream the signal to the other hearing aid. Not only does this feature allow the wearer to hear the caller in through both hearing aids, it effectively excludes any ambient noise in the room. Electromagnetic fields can also be created in a room by installing what is called an induction loop around the perimeter. Anyone in the room who is wearing an equipped hearing aid can easily switch to telecoil for ease of listening. Many public spaces use this technology to ensure access for all individuals with hearing loss. There are usually headphones provided for those who have difficulty hearing but do not have hearing aids.
Traditional FM systems are composed of a transmitter (a microphone) that is worn by the person speaking and a receiver that has to be attached to the hearing aid(s) of the wearer. In wireless hearing aids, the FM receiver may be embedded in the processor so that an external receiver is not needed. With the FM receiver built into many wireless hearing aids, it has become much more convenient to use. An FM transmitter may be carried with you to a business meeting, dinner out with your family or a lecture hall. The transmitter becomes an extension of your hearing aid microphones, vastly improving your ability to hear in many complex listening environments. FM systems are essential in classrooms for children with hearing loss. With a lapel-worn transmitter, the teacher's voice can be clearly delivered to the child (or children) with hearing aids while the teacher is walking around the room.
The Bluetooth standard is a fairly new technology that has the potential to impact hearing aids in a big way. Most wireless hearing aids on the market are able to pair with Bluetooth devices by utilizing an intermediary device.This device, or streamer, can translate the Bluetooth signal into a signal that can be picked up by an FM receiver or telecoil. For example, your wireless hearing aid may be connected to a streamer that is then connected via Bluetooth to your cell phone. When you have a phone call, the streamer would indicate the incoming call and allow you to activate the relay of the audio signal directly to your hearing aid. Introduced in the spring of 2014, the newest Bluetooth-compatible hearing aids are able to directly communicate with Apple's latest iPhone devices. This patented technology may exclude other mobile phones for a time, but is the first step towards direct connectivity for all types of media using the Bluetooth standard.
Hearing devices that can pick up wireless signals put us all in touch again, regardless of the means. Wireless transmission of sound data between two hearing aids benefits hearing aid users every day with better sound quality, improved localization, convenience and vastly increased connectivity.
- Getting hard of hearing people "in the loop," Hearingloop.org, http://www.hearingloop.org