I haven’t focused a lot on the specifics of hearing assistance technology in this blog, but I can’t think of a better item to talk about than the telecoil. Wait, really? Isn’t there something sexier to talk about?
No, not really. This simple, unsung hero of an option on a hearing aid or cochlear implant can make the difference between tuning in or tuning out. Hearing aids and cochlear implants may be very effective in quieter settings, but when noise is introduced, the hearing device alone may not be able to adequately create a satisfactory signal-to-noise ratio. For people who have a hearing loss, the sound that they want to hear (signal) needs to be significantly louder than the surrounding background sound (noise) in order for it to be understandable. Although hearing aids may have some technology to reduce background noise, it can also compromise the speech signal. This is why using an additional assistive listening device (ALD) is so important. Telecoils are a simple option to hear better on the phone and to connect with ALDs.
How Telecoils Work
To understand how telecoils work you need to know a tiny little bit about physics. 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). Telephone and stereo speakers give off this magnetic field unless the equipment has been shielded to prevent it. In ALD terms, an induction loop is a loop of wire connected to a sound collection system (like a microphone and amplifier) that gives off a magnetic field carrying speech or music signals.
So what’s that got to do with hearing aids and cochlear implants? Well, the telecoil itself is a small metal rod wrapped in wired (oooh…see where this is going?). Telecoils were first put in hearing aids to assist in hearing on telephones when it was realized that they could take advantage of the leakage of this magnetic field that telephone speakers emit. The user simply flips a tiny switch on the hearing aid to turn it on. When the user places the phone speaker near the telecoil, the signal is picked up (i.e., the magnetic field from the phone induces a magnetic field in the hearing aid telecoil) and the hearing aid converts it to acoustic sound waves, amplifies the signal according to the individual’s hearing aid prescription, and sends the new amplified sound into the ear canal. Cochlear implants now have telecoils, and some telecoils automatically come on when a magnetic field is brought close to the ear.
The trick is to get the best signal reception from the telephone speaker to the hearing aid. The phone earpiece might need to be moved around the hearing aid to get the best reception. For example, 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 (even if it was in a shirt pocket or hanging around one’s neck), not over the ear for this signal reception with the telecoil.
How Telecoils can be Used
If hearing better on the phone isn’t enough, telecoils are an exciting option because they can also be used with a variety of ALDs. 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 that can be used in a variety of settings. See Beyond Hearing Aids for some examples.
Even if the room isn’t looped and 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 to listen through an FM or infrared transmission system is not a viable option. They need the specialized amplification provided by their hearing aid prescription. Covering the hearing aid ear molds with headphones can result in feedback. Listening through a neckloop and telecoil prevents this. A neckloop is a coated wire that is worn around the neck and plugged into the headphone jack on the FM or infrared receiver. Like its room loop big brother, a neckloop gives off a magnetic field that is picked up by the hearing aid telecoils. For people who can’t use headphones or who would prefer a more discrete set up than headphones, the neckloop is a desirable alternative.
Get in the Hearing Loop Campaign
A movement started in Holland-Zeeland, Michigan by David Myers to Loop America is spreading. The Hearing Loss Association of America and the American Academy of Audiologists worked together to help consumers and professionals Get in the Hearing Loop. I was honored to be invited to participate in this committee, and helped to develop the informational brochure on Assistive Listening Devices. Those interested in looping Oregon should contact Duane Smelser www.yourhearinghealth.com.
If you are working with someone who is getting ready to purchase hearing aids, or if you know someone with cochlear implants or hearing aids who has trouble hearing in noise, 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.
My Telecoil Haiku
Wire-wrapped metal rod
Carries magnificent sound!
Sexy enough now?
Sound Bites 