The Lowly Telecoil

By: Cheryl Davis

Editor: Here's Cheryl Davis with her encouragement to audiologists to include telecoils in hearing aids. This article originally appeared in the Spring 2008 PEPNet Perspectives.

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July 2008

The telecoil isn't new technology--but this simple and dependable hearing aid option can make the difference between tuning in or tuning out.

Hearing aids and cochlear implants can be very effective in quieter settings, but noise can interfere with a hearing device's effectiveness. For people who have a hearing loss, the sound that they want to hear (signal) needs to be significantly louder than other ambient sounds (noise) to be intelligible. Although hearing aids may have technology that reduces background noise, it often compromises the speech signal. That's why an additional assistive listening device (ALD) is so important, and the telecoil is a simple option to connect ALDs to hearing aids.

Telecoils work by induction. A wire with a current running through it naturally gives off a magnetic field. If another wire is placed near it, the magnetic field in one induces a field in the other. Magnetic fields carry signals. Sometimes the information is disorganized (e.g., static), and sometimes it is organized (e.g., music or speech). Telephones and stereo speakers give off this magnetic field unless the equipment has been shielded to prevent it.

A telecoil is a small coil of wire wrapped around a metal rod. Telecoils were first put in hearing aids to assist in hearing on telephones. The user simply flips a tiny switch on the hearing aid to turn it on. When the user placed the phone speaker near the telecoil, the signal would be picked up and the hearing aid would convert it to acoustic sound waves, amplify the signal according to the individual's hearing loss, and send the new amplified sound into the ear canal. The trick is to get the best signal reception from the speaker to the hearing aid. Early hearing aids were often body worn, not the compact components worn behind or in the ear. This means that the telephone speaker would be put over the aid (wherever it was worn), not over the ear for this signal reception.

The reason why telecoils are such an exciting option is that, if a room or area is looped with an induction system, the user does not need any additional equipment besides the hearing aid to enjoy improved listening. As long as someone is speaking into the microphone attached to the system, the signal will be sent out from the loop of wire through the magnetic field. Newer induction systems come in a variety of styles, such as free-standing small panels, chair pads, and floor mats. There is a movement in Holland/Zeeland, Michigan to loop it and other cities in Michigan and across America. For more information on this initiative, go to www.hearingloop.org.

Even if an FM or infrared system is being used, a telecoil can be useful. For people who need more amplification, removing their hearing aids to use headphones is not a viable option. Covering the hearing aid ear molds with headphonescan result in feedback. Coupling via a neckloop (a coated wire that is worn around the neck and plugged into the headphone jack on the FM or infrared receiver) prevents this. For people who don't want to be too obvious about using an assistive device (e.g., by wearing headphones in a classroom), the neckloop is a desirable alternative.

If you are working with someone who is preparing to purchase hearing aids, make sure he or she is aware of the inexpensive telecoil option. The consumer needs to advocate for this, as audiologists may not realize that the individual will be using ALDs. Especially in newer hearing aids and cochlear implants, the telecoil must be programmed. A great deal of confusion stems from consumers trying to use it without checking with the audiologist first to be sure that it has been activated and that it is adequately powered to provide a strong enough signal.
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