What is a Hearing Aid?
A hearing aid is a small piece of electronic equipment consisting of a microphone, receiver, amplifier and an ear mold. It is operated by a battery and adjustable volume settings. In most cases, people find hearing aids very helpful. Like eye glasses, hearing aids have to be prescribed and especially designed for the person who will wear them. While they amplify sound they do not restore normal hearing.
Hearing aids cannot be 'shared' and are molded and programmed specifically for an individual. The type of hearing aid recommended by an audiologist will depend on:
- the type of hearing loss you have
- your degree of loss
Understanding Hearing Aids
While there are several types and many brands of hearing aids, they all share some common features. Below is an exploded view of a typical Behind-The-Ear (BTE) hearing aid. The parts are as follows:
| A | Function Switch | Usually M-T-O (microphone, telecoil and off) |
| B | Battery | Supplies power to the amplifier |
| C | Microphone | Converts acoustic energy to electrical energy. |
| D | T-Coil | Converts magnetic energy to electrical energy. |
| E | Amplifier or Circuit | Increases the strength of the electrical signal. Also filters and modifies the response of the hearing aid to match the hearing loss of the user. |
| F | Volume (Gain) control | Allows the user to increase or decrease the over-all level of the sound after the amplifier. Many newer hearing aids have automatic gain control. |
| G | Receiver | Converts electrical energy to acoustic energy. |
| H | Sound hook (tonal tube) | Delivers the sound from receiver to the ear mold. May be filtered to further adjust the signal to match the hearing loss. |
The Hearing Aid Switch
Most "behind-the-ear" hearing aids have the markings M, T, and O under the switch. M stands for "microphone" and means that the aid is switched on. T stands for "telephone" and indicates that the hearing aid is set for the "telecoil" position - which means that the microphone is switched off, that is, the hearing aid is not picking up regular sounds. When the setting reads MT (together), this indicates that both the microphone and telecoil are activated. O means off. Therefore always make sure that when the hearing aid is in regular use it is switched to "M".
Some hearing aids have different letters such as N or H. These letters refer to "normal" and "high". Normal is for regular use (like m) and high refers to cutting out the bass/low tone sounds which are more prevalent in noisy surroundings.
The Volume Wheel
Once the hearing aid has been put on, the volume control should be set at the most comfortable level for the recipient.
The Earmould/ITE Hearing Aid Shell
It is very important, both for the comfort of the resident and to prevent "feedback" (whistling) that the earmold be a good fit. The mold should be cleaned and checked for wax regularly. Wax can be removed from the inside of an earmold with a small pin. The mold may be cleaned with facial tissue.
Remember never get the aid itself wet. If you wish to wash the mold remove it from the hearing aid. Make sure however, that the mold is completely dry before reconnecting it to the hearing aid. In order to clean an in-the-ear type hearing aid, just wipe it with a slightly damp cloth but do not try to remove wax from the canal portion with a small pin. This will only result in pushing the wax further into the hearing aid causing it to malfunction.