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Loud and Clear

by Karen D. Schwartz

Hear that? It's the sound of a technological revolution for the hearing impaired. Bluetooth® wireless technology turns hearing aids into headsets for phones, MP3 players and more.

There was a time, not too long ago, when hearing-impaired individuals who use hearing aids had to wait to reach a landline before they could make or accept business calls. Cell phones tended to create so much audio feedback in the hearing aids that it could be difficult to hear conversations.

"Conventional hearing aids and cell phones used together is problematic, because there is a lot of static, usually from radio interference, which causes a lot of static sound in hearing aids," explains Crilles Bak Rasmussen, a research and development engineer for Copenhagen, Denmark–based Oticon A/S. "Those problems result in many hearing aid users taking off their hearing aids when using cell phones, which means they don't get the proper amplification. It results in a bad experience."

Today, thanks to Bluetooth technology, which essentially turns hearing aids into wireless headsets, those with hearing loss can talk on their cell phones with ease. Hearing aid systems with Bluetooth wireless capabilities allow users to not only talk on their cell phones without annoying feedback, but also to listen to Bluetooth enabled MP3 devices, hear the television and more.

The world's hearing-impaired population – about 278 million people, according to the World Health Organization – can greatly benefit from Bluetooth enabled hearing solutions, like those from market leaders Oticon and Phonak. These systems correct some of the most common problems for hearing-impaired cell phone users.

While manufacturers may approach the technology a bit differently, most focus on creating binaural sound. By transmitting sound to both ears through two separate channels, the hearing aids work in tandem to produce a stereophonic effect, similar to normal hearing.

Oticon's Agil, Streamer and ConnectLine

Oticon's Agil is a second-generation family of wireless hearing instruments that make use of three audiological advancements to improve the wearer's ability to organize, select and process sounds. Spatial Sound 2.0 is an advanced binaural processing system that preserves naturally occurring spatial cues and provides a better signal-to-noise ratio for improved understanding.

The Speech Guard dual-analysis signal processing technology improves speech by preserving the fine modulation and details of the sound signal even in environments where sound levels change rapidly or where hearing soft sounds would be a challenge. Connect(+) improves the sound quality of streamed music by restoring bass frequencies typically lost through open fittings.

Oticon's hearing devices work in concert with Streamer, a gateway device worn around the neck or in a pocket that connects audio devices with hearing aids via Bluetooth technology. With the Streamer, Agil users can stream sound directly from cell phones, MP3 players, PCs and other Bluetooth enabled communication and entertainment devices to their hearing instruments. Users hear sound in both ears, processed through the hearing devices to address their individual hearing needs.

The Streamer also works with the recently launched ConnectLine, a system of connectivity solutions that enable hearing instruments to connect wirelessly with a full range of Bluetooth enabled devices, including televisions, radios and landline telephones. Users simply pair the Streamer with any Bluetooth enabled device; ConnectLine automatically connects the devices to their hearing instruments whenever the Streamer is activated.

Phonak's SmartLink and iCom

Stäfa, Switzerland–based Phonak AG, another major player in the hearing aid industry, entered the Bluetooth wireless market in 2004, when it introduced SmartLink. Similar to other gateway-type devices, SmartLink uses Bluetooth technology to create a bidirectional digital link between hearing aids and mobile phones or other Bluetooth enabled devices. In 2009, the SmartLink transmitter was updated to the SmartLink+ featuring the revolutionary Dynamic FM technology.

A major benefit of SmartLink+ is that it can be combined with virtually any hearing aid, so the hearing-impaired can, in nearly every case, continue to use their existing hearing aids with SmartLink.

"Since Bluetooth wireless is such a well-established standard, it really is, for us, the primary way to develop connectivity between the Phonak SmartLink+ microphone and the cell phone," says Pat Henry, director of Government Services, Wireless and Pediatrics for Phonak USA in Warrenville, Ill. "It is proven, so we definitely are continuing development of new products with Bluetooth."

One such development is Phonak's CORE hearing device platform that, when paired with the iCom communication interface, wirelessly connects to a huge variety of external Bluetooth enabled devices. iCom's binaural StereoSound digital transmission is extremely robust against any sort of interference. Also on the market, Phonak's new TVLink allows users to connect their hearing systems to a TV in stereo CD quality via Bluetooth technology.

"Our CORE platform hearing devices bridge the long-standing gap between the hearing instrument industry and the consumer electronics industry, providing wearers the same level of connectivity as anyone else," notes Phonak's Mike Orscheln, the company's president and chief executive officer.

"Today's technology isn't just about hearing aids," Henry adds. "It's really about developing communication systems that provide access to all hearing-impaired individuals."

Low Energy Technology Advantage

Although it's clear that Bluetooth technology can help transform the hearing aid industry, more must be done before the hearing-impaired population can experience wide-scale benefits.

Power requirements present a challenge. Hearing aids must do a lot with a limited amount of battery drain while performing complex tasks such as real-time noise reduction, directional sound identification, automatic feedback cancellation and customized frequency amplification. Classic Bluetooth technology simply requires too much battery power to fully integrate with what the hearing aid must do, notes Dr. Paul Dybala, president and editor of audiologyonline.com, an information resource for the hearing impaired.

In most cases today, an external gateway device (such as the Oticon Streamer or Phonak's SmartLink+) uses a low-power wireless protocol to talk to the hearing aid. The gateway device then uses Bluetooth wireless technology to connect with other devices, such as cell phones. Because these gateway devices are relatively large – the Oticon Streamer, for example, is approximately the size of a typical MP3 player – they can have larger batteries. But that has to change if Bluetooth technology is going to revolutionize hearing aids.

"The key is getting the power requirements low enough so you can fit all of the technology into the hearing aid itself," Dybala says. "Bluetooth seems to be the wireless standard that will unite all of this. The low-power requirements of hearing aids eventually will be met and hearing aids will be able to take advantage of the universality of Bluetooth to help people communicate more effectively through audio devices."

The advent of Bluetooth low energy technology, the hallmark feature of the Bluetooth Core Specification Version 4.0, answers the challenge of battery drain. And, given the rate at which technology advances, it may not be long before a Bluetooth wireless radio inside a hearing aid will eliminate the need for additional accessories. It will also allow direct communication between computers and certain types of programmable hearing aids.

© 2013 Bluetooth SIG, Inc. All rights reserved.