Wireless hearing aids

Bluetooth technology, initially used for hands-free mobile phone communication, provides the ability to wirelessly stream audio signals from one device to another. Hearing aid manufacturers have leveraged this technology so that audio signals can be sent from phones, tablets, MP3 players, televisions, etc. to hearing aids, essentially transforming them into personal headphones. Almost all of today’s new hearing aid models are Bluetooth-enabled.

Streamer: For older hearing aids that don’t have built-in Bluetooth technology, an intermediate device worn around your neck receives the Bluetooth signal. Using a neckloop antenna, the signal is sent via NFMI to the hearing aids. Some streamers double as remote controls, enabling you to adjust the hearing aid volume and change listening programs. The only drawback is that some people don’t like the size and visibility of the streamer device.

Operating as a wire receiver, many hearing aids are equipped with a coil of wire that operates as a miniature wireless receiver. Originally designed to make sounds clearer to a listener over the telephone, the telecoil works by receiving an electromagnetic signal from the hearing loop and then converting it back into sound, thereby eliminating distracting background noise. It can also be customized to match a person’s hearing loss pattern.

Short for frequency modulation, a typical FM unit consists of a small transmitter microphone worn by the person speaking and a radio-frequency (RF) receiver. The microphone picks up the voice of a speaker, then sends the clear speech to the RF via a wireless connection. Hearing aids or cochlear implant with telecoils enable the listener to wear a neckloop with the receiver or behind the aid or implant (called a silhouette inductor). This device converts the signal into magnetic signals that are picked up directly by the telecoil. Although reproduction of the same signals in both ears increases the ability to understand speech, it doesn’t reproduce spatial cues, which enable listeners to determine the location of sounds (where they originate). In the U.S., FM technology is used mostly in educational settings since it’s cost-prohibitive at an individual level. 

The introduction of digital technology in bone conduction devices has substantially improved hearing performance. Yet users still encounter problems communicating in everyday situations. And an unmet need exists on the part of many users to stream audio and direct connections from mobile phones and/or landline phones, televisions, and remote microphones to their bone-anchored hearing devices.

The efficacy of wireless connectivity may be different with bone conduction devices than with conventional hearing aids. With conductive or mixed hearing loss, the effect of direct, unamplified incoming sound is reduced by the conductive component of hearing loss. This affords some freedom to optimally combine wireless and acoustic input signals.

In listeners with predominantly high-frequency hearing loss and relatively good low-frequency hearing (e.g. age-related sensorineural hearing loss), large-vented ear molds or open fittings are often needed to reduce occlusion effects and enable perception of natural, low-frequency sound. A delicate balance must be maintained between amplified high-frequency sound and unamplified low-frequency sound. This leaves less room for customizing wireless signals relative to direct sound input into the ear canal.

• A recent study evaluated the effectiveness of wireless connectivity by comparing a sound processor with wireless and acoustic sound processors and a body-worn streamer to its predecessor that only used an acoustic sound processor and microphone. Nineteen people (ages 26 to 72) with bilateral conductive or mixed hearing loss who had worn a bone-anchored hearing device for at least two years participated. Thirteen people were fitted unilaterally and six were fitted bilaterally. Most of the scores were similar, however, participants preferred the device with the wireless component for speech quality, speech understanding in quiet and noisy settings, and less ambient noise while talking on the telephone and watching television programs.

Sound quality: Streaming audio directly into hearing aids produces sound that improves the signal-to-noise ratio (SNR) problem involving noise, distance, and reverberation. This is accomplished through SNR directionality and feedback cancellation sound processing. The benefit is most apparent in bilateral hearing aids, enhanced microphone systems, and streaming of sounds from other sources.

Hearing in noisy settings and speech understanding: People with binaural hearing can accurately locate different sounds and understand speech in noisy environments. Advanced hearing aids with a wireless connection between the left and right devices deliver several benefits. A network of several microphones can enhance the performance of certain signal processes. Dynamic compression between both devices can better preserve necessary spatial cues to hear in noisy settings.

Difficulty understanding speech in noisy settings is the primary complaint of individuals with sensorineural hearing loss. Study participants who were fitted with a wireless binaural broadband digital hearing device scored significantly higher on SNR and hearing in noise tests compared to those fitted with advanced digital hearing devices. Research shows hearing aids that incorporate wireless systems consistently improve the perception of signals emitted by a loudspeaker, even in extremely noisy settings.

Convenience: Wireless exchange of information between bilaterally worn devices enables automatic selection and alignment of the microphone mode and noise reduction settings, as well as synchronizing volume control. The ability to connect with other electronic devices offers ultimate convenience.

Connectivity: Smartphone-connected listening devices connect wirelessly via Bluetooth to smartphone technologies, enabling users to conveniently personalize and adjust their hearing device programs. Smartphone hearing aid apps enable smartphones to perform like conventional hearing aids with either wireless or wired earphones, which can be adjusted by the user.

• A 2018 study on 26 hearing aid users analyzed and compared made-for-smartphone hearing aids, a personal sound amplification product, and a smartphone “hearing aid” application used with either wireless or wired earphones. Compared to conventional hearing aids, self-reported use, benefits, satisfaction, and usability were higher for the made-for-smartphone hearing aids. The other two technologies were rated lower on all these variables.

If Tesla was alive today, he would be amazed by all the ways wireless technology has transformed the daily lives for billions of people and helped those with hearing loss in the process. If you’re struggling with an older hearing aid, schedule a consultation with a licensed hearing professional. You’ll likely discover that advanced wireless hearing aid technology can enhance your quality of life, just like it has for so many other people with hearing loss.