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Hearing aids and telephones

Dr John Gill
December 1995


Hearing aid users often find that they have difficulties when using the telephone. In fact many people take their hearing aids out or use the phone on the other ear, if they have sufficient hearing in it. Below are some ways to reduce these difficulties and make better use of the telephone and the hearing aid. No matter how good the hearing aid or telephone, if the person speaking to the hearing aid user does not speak clearly or speaks too quickly the hearing aid user will still have difficulties.

Using a hearing aid directly with a telephone (acoustic coupling)

Here there are likely to be two problems. The first is that when the telephone is brought up to the hearing aid, it may cause the aid to whistle. The second is that using a telephone when there is external noise nearby will make it more difficult to understand speech from the telephone.

In these circumstances if often helps to turn down the volume control of the aid. This has the effect of reducing the possibility of the aid whistling and at the same time lowering the level of the surrounding (background) noise and this helps to make the speech clearer. For users of body worn aids the telephone can be turned upside down as in the picture, but still turn the volume control down.

The "T" switch position (inductive coupling)

The use of the "T" switch position is very important as it completely overcomes the problems above of the aid whistling and also reduces background noise. Many people find that they hear better using the telephone this way.

Hearing aids often have a switch which not only turns the aid off and on, marked "O" for "off" and "M" for microphone, but also a position marked "T".

When the switch is in the "T" position the microphone is disconnected and no sound is heard from the aid because the microphone has been replaced by a pick-up coil. This coil does not respond to sound but does respond to magnetic signals which can be picked up from a telephone which has an inductive coupler fitted telephones fitted with inductive couplers are called "hearing aid compatible" or may be marked as follows:

You cannot tell if a phone has an inductive coupler by its external appearance because the inductive coupler is fitted inside. Before buying a telephone try it with your hearing aid in the "T" position to see that it has an inductive coupler which gives you sufficient sound, as not all telephones give out the same level of magnetic signal. In many countries all public telephones (payphones) are fitted with inductive couplers.

Using the "T" switch

If the telephone has an inductive coupler then switch your aid to "T" and place the telephone earpiece over the ear in the normal manner. You may now have to move the telephone around to get the loudest signal. You may also have to adjust the volume control on your hearing aid to give you a comfortable level of sound. Once you have done this you can then go ahead and make the call as normal.

The telephone as a hearing aid

The telephone itself is a good hearing aid and many people with small hearing losses find that they hear well on the phone. This is because the person speaking at the other end of the line is talking right into the mouthpiece and the sound is then fed straight into the listeners ear. It is important for the person speaking to hold the mouthpiece of the telephone directly in front of the mouth and for the listener to hold the earpiece firmly and centrally over their ear. This is sometimes a problem for elderly people who let the telephone handset drop away from the mouth and the ear.

GSM digital mobile telephones

Hearing aid wearers may find difficulty in using a GSM mobile telephone due to interference from the radio transmission. It is difficult to predict which aids will be immune to interference and therefore the only advice is for hearing aid wearers to try their aid with a GSM phone. If interference is present it is unlikely that there is any way in which that aid can be used with a digital phone. Mobile phones in general do not provide facilities for induction coupling.

 

 



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