The way we gather and process sound is often taken for granted. In fact, it’s a fascinating, intricate and finely balanced thing, involving a series of complex collectors, transporters and processors. Unfortunately, this means that there are multiple ways that your auditory system (hearing) can become ineffectual.
The causes of hearing loss are often categorised in four ways:
- Auditory Processing Disorders – which is when the brain struggles to interpret sounds.
- Conductive – the main cause of hearing deficiency, explained fully below.
- Sensorineural – which is when there is defect or traumatic damage to the mechanisms inside the ear.
- Mixed – a combination of any of the above!
What is conductive hearing loss?
Millions of people in the UK suffer from conductive hearing loss, and some may be largely unaware of the issue, as it has ‘crept up’ on them gradually!
The common view that hearing loss is ‘going deaf’ is not altogether accurate. It can also be a fall in the quality of the sounds you hear, rather than how quiet or loud they are. It could be certain pitches or types of sound you struggle to hear clearly.
For other people, the main symptom of conductive hearing issues is pain, discomfort or feelings of intense pressure inside one or both ears. Perhaps you find yourself tilting your head to concentrate on gathering sounds or having to turn your TV louder and asking people to repeat things.
The first symptom could even be unpleasant smells coming from your ear or ears!
All these indicate conductive hearing loss, so let’s look at how this happens.
Causes of conductive hearing loss?
“Conduction” means that something invisible is being moved. In relation to your auditory system, it’s sound travelling from your outer ear to your brain. This is a quick, automatic process for anyone with healthy hearing. Conductive hearing loss indicates a blockage or interruption in this process.
Problems in the outer ear are relatively straightforward to diagnose and treat. For example, a build-up on ear wax could block sound. Another common cause of conductive hearing loss at this location is an infection (the source of the bad smell) which has inflamed the external ear canal and reduced its effectiveness.
There can be more serious causes of hearing loss associated with the outer ear, such as tumours or abnormal bone growth in the auditory canal. Some babies are born with a badly formed outer ear structure that struggles to transport sound waves.
One of the most common causes of hearing loss in your middle ear is a build-up of fluid that blocks or distorts sound waves. This is especially common in young children and often referred to as having a ‘glue ear’. For adults or children, this can be alleviated by inserting small temporary tubes (Grommets ) to drain the fluid.
The middle ear largely consists of the Eustachian tube, which is 35 mm long and filled with air. Hearing effectiveness is impacted by the level of pressure in this tube, which enables it to pass vibrations to the membranes of the inner ear. If the pressure is wrong, sound can be dull.
The source of the pressure changes could be allergies and infections, or more seriously some form of tumour.
The Eustachian tube can often be the place where temporary loss of hearing happens, such as when you have a severe cold or you travel in a pressurised airplane cabin. You may need to ‘reset’ the pressure by yawning, swallowing or chewing.
There are other parts of the middle ear that can cause conductive hearing loss, especially your ear drum. This crucial membrane for conducting sound waves can develop a perforation (hole) due to excessive pressure ‘bursting it’ for example. As it heals, scar tissue creates hearing difficulties.
The inner ear takes the vibrations from your eardrum and transports them through three tiny bones. Specialist cells then transform the vibrational energy to electrical impulses, which pass along the auditory nerve to your brain, where the sound is understood.
This all happens in an instant. If something goes wrong in the inner ear, this too leads to hearing loss, but it can be much trickier to diagnose and treat.
It is quite common for inner ear problems to be “sensorineural” hearing loss caused by such things as severe knocks to the head or significant viral infections such as measles, for example.
How can different causes of hearing loss be treated?
Treatment for conductive hearing problems varies according to the location and severity of the problem.
Some issues need surgery to correct damaged or badly functioning auditory ‘equipment’. Other causes of hearing loss can be rectified by medicines, such as antibiotics.
It is not uncommon for conductive hearing loss to have no quick fix solution, requiring the use of a discreet device. With the correct diagnosis and support, modern technology often makes it possible to have hearing restored to a normal level, improving both sound perception and quality of life