Friday, 13 January 2017

How hearing aids work

A hearing aid is a piece of electronic device which assists in restoring sound to persons with impaired hearing by the amplification of the sound. It does this by picking up the sound waves arriving at the external ear, processing them and sending the amplified sounds back into the ear.

Hearing aids now employ various types of hearing solutions to achieve this objective but they are all made up of essentially similar component parts. An amplifier picks up the sound waves as they arrive at the external ear and converts them into digital signals which are processed by a microchip, a mini-computer, installed within the hearing aid. The microchip is programmed by an auditory professional to meet the specific needs of the user, based on the results of a hearing test and the lifestyle of the user.

The signals are then strengthened by an amplifier to boost them before being converted into vibrations by a receiver which transmits them to the brain via the inner ear. The microchip is a sophisticated computer-like silicon chip which continuously modulates incoming sounds to ensure that only clear and audible sounds of the appropriate level of amplification can be transmitted into the ear. This whole device is powered by a tiny battery installed within it.

Analogue hearing aids previously in use do not have these capabilities even though they amplify sounds, but some are equipped with ‘automatic gain control’ features which enable them distinguish between quiet and loud sounds so that loud sounds are not further amplified to levels uncomfortable for the user.

Some hearing aids are combined with a sound generator. These combination devices are produced to assist persons suffering from tinnitus. The sound generator provides extra low level sounds which help in getting used to the tinnitus sound.

The modern digital hearing aid automatically adjusts itself to the sound level in the environment so that the user seamlessly adjusts to the varying sound waves arriving at the external ear. This way, the user is able to take part in conversations even when some participants are barely audible while others are speaking at the top of their voices.


Digital technology now makes it possible for modern hearing aids to be worn discretely. Some are so tiny they are barely visible because they sit far enough within the ear canal no one will notice them. The most advanced ones offer a wide range of personalisation options and they can deliver higher quality sounds with more natural listening experience. They can be enhanced to connect wirelessly to devices such as mobile phone, tablet, TV or stereo system. 

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