Hearability Limited

“We only hear what we want to hear” - True or False?

Well actually it is more true than it is false. The brain plays a very important part in the way we interpret and process sound.

Most of us hear well and so don’t give much thought to how we hear but hearing starts with a very complex set of actions within the outer, middle and inner ear. These actions allow our brain to understand sounds. For example the ears are two separate organs but the brain allows us to hear in stereo and at precise synchronicity. If you put one ear close to a speaker or turn your head to concentrate a sound to one ear, despite the fact one ear is much closer to the sound than the other ear, the brain ensures we hear the sound in unison. Furthermore the ability to hear in stereo allows the brain to understand in which direction a sound is coming from.

This partially explains why an audiologist will often recommend two hearing instruments although a hearing loss maybe concentrated to one ear more than the other. With the two hearing aids sharing the same technology and capability the brain can more easily process sound in the way it is used to. The medical or scientific term for hearing is Auditory Processing.

The degree to which the brain is involved in the hearing process has been the subject of research by the Hearing Research Unit of the Medical Research Council that have concluded that people do suffer Auditory Processing Disorder (APD). This is when people’s ears are working well but they cannot understand the sound they hear.

Typical indications are difficulties listening in noise, understanding and following verbal instructions and poor auditory memory. The majority of the research to date has been focused around children where it is believed the condition is most prevalent. Whilst the research is in its very early stages and far from anything conclusive but early indications suggest there maybe a links between ‘glue ear’, (APD) and the diagnosis of Dyslexia.

Hearing what you want to hear

Without question the brain learns to ignore sounds it is not interested in despite the ears being able to pick up the sound. Someone living by a railway line for instance is a prime example. Over a period of time the brain chooses to ignore the sounds of the trains and in contrast how often do you find yourself in a busy place yet still able to overhear your name being mentioned. The fact is the brain learns what is called ‘Selective hearing’ – it learns to disregard the sounds the mind is not interested in.

Learning to hear again

During the progression of hearing loss, the brain loses its ability to be ‘Selective’. So when hearing is restored with the aid of hearing instruments the brain has to relearn how to interpret the restored sounds. In the early days of using hearing instruments the discovery of sound again can be quite disorientating but it is essential the user perseveres to restore ‘Selective hearing’. The medical term for this period of time is called ‘Rehabilitation’ and it may require more than one return visit to the hearing aid dispenser to ‘tweak’ and gradually readjust the instruments to ones personal expectation and lifestyle. Indeed the more sophisticated hearing instruments have ‘Data Logging’- this is where the instrument records the sounds and environments it has been subject to and how long the instrument has been in use.

This aftercare should be included in the purchase price of instruments from a qualified hearing aid dispenser and should be limitless.