A hearing aid is defined as a device that typically fits behind or in the ear and is designed to amplify those frequencies of sound that the wearer has difficulty hearing.
Although they come in a variety of shapes and sizes, hearing aids all work in exactly the same way.
Inside the hearing aid is a microphone that picks up the sound around it, such as speech, traffic noise, birdsong etc, and this is turned into digital information using micro-processors inside the hearing aid. This digital information is sent to the receiver which acts like a tiny loudspeaker than converts the information back into sounds you can hear.
But the key is that only the sounds that the wearer has trouble hearing will be amplified beyond the normal level and this is done by programming the hearing aid to work differently depending on the environment. Depending on the specification of the hearing aid, these programs can then be selected by the wearer as and when required, or the hearing aid can select them automatically.
While hearing aids will not restore your hearing completely, they will improve your quality of life. They will make conversations easier and increase your confidence when talking in groups or on the telephone.
Just as glasses have two lenses, one for each eye, when you need help with your hearing you will most likely need a hearing aid for each ear. This is called a binaural fitting. People with two hearing aids tend to find it much easier to follow conversations in background noise, and can more easily tell what direction sounds are coming from, i.e. a car on a busy street.