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The simplest hearing tests consist of whispering standard phrases at varying distances from the person`s ear. Next come tests with a tuning fork which the doctor taps and holds against the person`s ear. Once the humming fades, the doctor move the fork an inch or so away from the person`s ear until he or she can no longer hear any sound.

More sophisticated tests are done with a machine called an audiometer. These are conducted in a soundproof room, with the person wearing earphones. A machine emits notes at different volumes, beginning with sounds beyond the hearing range and gradually bringing down the sounds until they are just audible. The person signals that he or she can hear the sounds by pressing a button. The audiometer measures the air conduction from the sound emitted and heard in the earphone. It also tests what is known as bone conduction, when the sound is played directly into the bone of the skull, thus bypassing the external and middle ear.

The results can be presented graphically, with frequency and hearing loss plotted on a scale.

Hearing aids

Hearing aids deliver amplified sound directly to the ear. The oldest type was the ear trumpet, which collected sound in the outer trumpet and directed it to the eardrum. The more recent electronic hearing aids contain a microphone, which picks up sound, an amplifier to make the sound louder and an earphone, which delivers the sound to the ear.

There are three types of hearing aids.

The `body-worn` hearing aid which is battery powered and is clipped to the person`s clothes. Its disadvantages are the unsightly cord and the fact that the microphone, which collects sound, is often located at chest level whereas people tend to speak at ear level.

Modern `behind-the-ear` hearing aids are miniature version of the earlier models. Their chief advantage is that the microphone is situated at ear level and the device is clipped on neatly behind the ear.

`Inside-the-ear` hearing aids, which are quite tiny, are built into a mould that fits the patient`s ear: all the components are miniaturised by the use of the silicon chip.

Using a hearing aid

While using a hearing aid, there are lessons to learn for both the wearer and the other members of the family. For the user, it would take a while to get used to the hearing aid. All sounds in the room get amplified when the hearing aid is on. The members of the family must learn some ground rules also.

Here are some tips on what to do.

A user listening to others speaking

1. Start quietly and practise listening to a person speaking.

2. Adjust the volume control to suit the level of your speaker.

3. Ask your speaker to sit in a good light so you can see his or her face. Partial lip-reading may be helpful.

4. If you are with a group, try to sit in the middle so you can hear those around you.

   Speaking to those who are using hearing aids

5. Cut down outside noise by shutting doors and windows.

6. Face the person and keep your hands away from your face. Speak directly. Your listener may also be lip-reading.

7. Speak slowly and definitely. Don`t shout as this overloads the amplifier and distorts the sounds they hear.

8. If your listener does not understand a question, repeat it. If this fails, then rephrase it in a simpler language or write it down on paper.

9. Don`t jangle keys or click fingers or pens: this may distract their attention or produce masking background noise.