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Dr. Ross on Hearing Loss

Bluetooth and Hearing Aids: Ready for Prime Time?

by Mark Ross, Ph.D.
This article first appeared in
Hearing Loss (Nov/Dec 2008)

When I was growing up in New York City, it was not uncommon to see someone having an animated conversation, apparently with himself since no conversational partner could be observed. It was rather a strange sight, but since the people doing this were generally harmless (except perhaps to themselves) they were basically ignored as they walked and talked. In my recent visits to NY, I see the same apparent phenomenon - only multiplied a thousand fold.  On just about any street in midtown Manhattan, there are people walking and talking, apparently to themselves, seemingly oblivious to their surroundings. Upon close examination, however, they all have one thing in common: a bluetooth receiver sticking out of their ears. It is clear that they are talking to a real human being, using a cell phone with a hands-free arrangement; no one categorizes them as having some sort of psychological problem (at least on this basis!). People with hearing loss want to know if they too can use a cell phone, in the same cool and convenient manner, with a bluetooth connection. The answer is that they can, but not in the exact same way. Although hands-free connection can be made, it is not quite as easy to do as it is for someone with normal hearing, at least not presently. 

Bluetooth came by that strange name just about ten years ago when a consortium of electronic companies, mainly from Scandinavia, joined together to agree on a common wireless protocol. The term refers to an ancient Nordic king who united many tribes in a single kingdom. Essentially, this is what the bluetooth operation does; it wirelessly connects (unites) all sorts of electronic devices. It does this by transmitting a detailed set of operating instructions from one electronic component to another. The information is coded so that the transmitted signal is received only by an intended receiver. Early examples of bluetooth operation were between various computer components, later extended to cell phones and a host of other devices. Among its advantages is its low power and limited transmission range; this helps ensure an interference-free signal that can be received only by the intended recipient of the message.  For hearing aid users, the major potential advantage of bluetooth at this time lies in the distortion-free access it can provide to cell phone communications. While there are other electronic sound signal outputs that can be accessed via a bluetooth receiver (e.g., an mp3 player, TV, computer, etc.), right now the potential application with cell phones seems the most   pertinent.

In spite of the many advances in wireless communication and hearing aids (in part because of the advocacy efforts by the HLAA), the quality of the verbal signals heard through hearing aids may still be contaminated by various sorts of interference (ambient electromagnetic noise, sound fluctuations caused by hearing aid positional changes, etc.). Then, too, hands-free conversation, which would be a major convenience for some hearing aid users (besides just looking “cool”), is not possible with the conventional use of a cell phone. Hence, the interest in bluetooth technology by hearing aid companies; they have identified a need and it is in their business interest to fill that need.  A few manufacturers have responded to this challenge, each in their own way.  

Several years ago, the Starkey Company marketed the ELI, a “miniature” (about one inch long) bluetooth receiver that could be plugged into the base of a behind-the-ear hearing aid. With it, one could directly connect to a remote cell phone (in a purse or on one’s belt, for example) and carry on a distortion-free telephone conversation. It was (and is) the only device that permitted a direct electrical connection to a hearing aid from a bluetooth receiver; I tried it myself and I thought it worked well. However I have recently learned that the ELI (along with two companion products, a remote bluetooth transmitter and a neckloop) is no longer being made and marketed; evidently, ELI was not yet ready for “prime time.” As well as it worked, it was not adopted by enough people to make it an economically viable product. People who now possess the ELI or the ELI neckloop (into which the ELI module is plugged) can still realize a hands-free arrangement while using their cell phones, but the current generation of this product line is being phased out. 

The Phonak Company has two entries in the bluetooth market. The first is the Smart-Link FM microphone/transmitter, which has included bluetooth capability from the time of its introduction some four years ago. Pairing and connecting the transmitter to a compatible cell phone (one that also include bluetooth capability) is a straightforward process (or so I’m told!). When a cell phone is paired to the Smart-Link, incoming calls will first be transmitted (via a bluetooth signal) to the Smart-Link which then re-transmits the incoming call (via an FM radio signal) to hearing aid(s) that incorporate FM capability. There is a possibility that this double transformation – from the phone to the Smart-Link and thence to the hearing aids - may affect the quality of the telephone message, but we don’t really know; generally, the fewer transformations a signal has to undergo, the better. Because of the limited range of a bluetooth transmission, in order for a phone call to connect to the Smart-Link the two devices must be in close proximity. Therefore, the most likely candidate for this use of bluetooth is someone who is a habitual user of both an FM system and a cell phone; for example, a person who routinely keeps the FM microphone dangling on a strap around his or her neck. So, with this procedure, while a “hands-free” connection to a cell phone can indeed be made, it can be done only by relaying the phone call via an FM transmission to the hearing aid. 

The other bluetooth compatible device offered by the Phonak Company is its iCom communication interface. This is designed to be suspended around the neck with a cord that doubles as an antenna. As with any bluetooth device, it is first necessary to pair and connect the intended transmitter and receiver, in this example the cell phone with the iCom. Calls are routed from the cell phone to the iCom via bluetooth, which translates the incoming message into discrete channels, one for each ear. This provides a true binaural signal, unlike that received via an FM system. The iCom will only work with  Phonak’s Exelia and Naida instruments since only these hearing aids contain the necessary coil to pick up the message broadcast by the iCom antenna. The iCom employs what is termed “near-field magnetic induction” (NFMI) to deliver the signal, via the neckloop, to a special digital coil located within the hearing aids. This coil is not to be confused with the traditional telecoil, which these hearing aids also contain. Both the Phonak products, the Smart-Link and the iCom, are basically relay devices, in which the phone message has to be retransmitted to the hearing aids using a third device. While they will provide the goal of a hands-free connection, they are still not as convenient as bluetooth use for someone with normal hearing.

Another example of a relay (or gateway) device is being offered by the Oticon Company, using what is termed a “streamer.” Like the iCom, the streamer serves to pair and connect the intended transmitter with the proposed receiver (a cell phone is the primary example in this article).  Both the streamer and the iCom appear to employ similar procedures and concepts. The streamer is worn around the neck, with the neckloop serving as the antenna, which transmits a near-field magnetic-induction signal to binaural Epoq hearing aids. This does not involve traditional inductive coupling that requires the use of telecoils, thus eliminating exposure to possible electromagnetic interference. 

The last entry (that I am aware of) in the bluetooth “relay” market is the TEK device, that is offered by the Siemens Company. As with the Phonak and Oticon offerings, this unit is designed to work with the latest, most technologically sophisticated hearing aids. These are hearing aids that can wirelessly connect to one another as well as to the relay device. The TEK is also suspended around the neck and retransmits a message via bluetooth from a cell phone to the hearing aids. It should be emphasized that the TEK and the other relay devices all include capabilities to receive and retransmit signals from other audio outputs besides cell phones. 

All four of the examples given above can provide a hands-free connection to cell phones, but only through some sort of relay device. All are similar in that the traditional telecoil is not being used, presumably to reduce possible interference from electromagnetic noise.   In the latest HARC catalogue (other venders may also carry these devices), two additional bluetooth-compatible receiver/neckloops are listed: the NZ-BEETLE H-2ST and the MAXIT Bluetooth Loopset. Each of these will also permit a hands-free connection to a cell phone by using a relay arrangement. Incoming calls are detected by the bluetooth receiver (located at the hub of the neckloop), and retransmitted to the hearing aid telecoils via the neckloop. The inclusion of a traditional neckloop and telecoils does increase the possible exposure to electromagnetic interference and movement effects, but the upside is that this arrangement is much less expensive than the three examples described above. 

While not explicitly designated for use by people with hearing loss, the SD-SM100 bluetooth receiver does include an amplifier and, reportedly, can simultaneously be used as a listening aid by some people with a mild or mild-to-moderate hearing loss.  It looks like the usual bluetooth receiver worn by normally-hearing people. However, it also includes an environmental listening mode with three levels of amplification for use when not talking on the phone. This is not a hearing aid and I would not advise someone to use it as such, but it can be convenient for someone with a hearing loss who spends a lot of time on the phone. In this instance, I would advise the use of a custom earmold, which can fit on the nub of the bluetooth receiver.  It also includes a listening mode that permits binaural listening with a receiver in each ear, at double the cost naturally (though this device is the least expensive of the ones described above).

My own assessment of the current state of bluetooth utilization by people with hearing loss is that there is less there than meets the eye. While bluetooth is one of the buzzwords in our society now, and is a proven technology for normal-hearing people, its use by people with hearing loss seems just a bit too involved. What hearing aid users would like is to have bluetooth capability incorporated within the body of their hearing aids. While there has been significant progress in the miniaturization and power reduction requirements of the bluetooth chip, it is still not at this point. Without this development, without direct access to the cell phone (or any audio output), I question the economic viability of any relay arrangement. Not only is it more costly, but it is less convenient. With this development, perhaps the dreams articulated by the BluEar Assistive Listening Consortium (described by the Drs. Jerry Yanz and David Preves in the November 2007 issue of The Hearing Journal) could finally be realized: access, through a common channel, that would pick up sound emanating from any sound source.

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