By Jason Galster
This article is a part of the July/August 2020, Volume 32, Number 4, Audiology Today issue.
Over the last 10 years, wireless technology has been a driver of innovation in hearing aids and cochlear implants. Today, our counseling narratives almost universally include discussion of the features and benefits that are enabled by wireless connectivity—it’s been a short trip from novelty to normal. This article reviews the evolution of ear-level wireless technologies and summarizes the landscape across hearing aids and cochlear implants.
On-ear wireless hearing devices (hearing aids and cochlear implant sound processors) can be first classified as having two basic modes of wireless communication: Magnetic induction and radio frequency (RF).
Magnetic induction systems transmit and receive signals at lower wireless frequencies (e.g., 10 MHz) with antennas that consist of a small magnetic core wrapped in a copper coil. In contrast, RF systems transmit and receive higher wireless frequency signals (e.g., 2.4 GHz) with antennas that are formed as a loop or strand of copper.
In the case of cochlear implant systems, the sound-processor headpiece uses a wireless inductive link to transmit power and data through tissue to the implant. For this article, inductive power and data transfer will be considered a separate wireless application and not a focus.
Among audiologists, the concept of wireless communication through magnetic induction is a familiar one. Hearing aids and cochlear implants have offered telecoils that receive audio from compatible induction fields for decades, the benefits of which have been thoroughly documented (Atcherson, 2019).
The early use of these magnetic induction wireless systems was motivated by a combination of size, low-power demands, and available technology. Still, today, the telecoil represents the most universally accessible method for providing directly streamed audio to a hearing aid or cochlear implant. However, the telecoil is limited by the need for proper alignment between the telecoil and the inductive field, as well as a very limited capacity to transmit data for signal processing.
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