HEARING LOSS
Hearing loss can occur at any age with serious consequences.
Hearing loss can be a blessing in certain cases but in the mainstay, it is a curse. Hearing is a vital special sense that many people take for granted, but for those that have had it and then start to lose it, the consequences can be quite significant.
Explaining hearing loss: 1. The conducting system of pressure wave on three bones:
It is important to understand how the hearing works. So, hearing commences with a noise, which is a pressure wave. This wave of pressure is caught by our external ear and it funnels the energy down the ear canal. At the end of that canal is the ear drum, which vibrates when the sound hits it. The bone connected on the inside of the ear drum moves as the sound hits the ear drum. This movement in turn leads to the bone moving another bone which then moves a third bone which amplifies the signal. The third bone has a small base that comfortably sits inside a small oval shaped window of the inner ear. The movement from sound from the outside to the small oval shaped window is called the ‘conducting system’.
2. The sensorineural component electrical current to the brain:
At the inner ear level, there is an amazing piece of biological engineering that transforms the movement of the third ear bone back into a pressure wave and then into an electrical current. This electrical current sends a message from the inner ear to the brain. The inner ear is where the actual sense of hearing is facilitated, and the nerves then carry this sensation to the brain. So, this part of the hearing system is the ‘sensorineural component’.
By understanding these two divisions of the hearing mechanism, we can understand the causes of hearing loss.
3. Five causes of conductive hearing loss:
• This is where there is a problem with either catching the sound, because the outer ear is absent which could be from birth, trauma, or surgical removal because of cancer.
• There may be an issue with the ear canal, such as being too narrow, or being blocked by wax or a foreign body of some sort.
• There could be a hole in the eardrum, so instead of the sound pressure wave meeting the intact drum, it just passes straight through the hole in the ear drum and the ear drum does not move.
• There could be fluid behind the ear drum, from an ear infection, and if this is the case, the sound waves hitting the ear drum are not able to make the ear drum move.
• The bones of hearing may have been dislocated or fractured or eroded by certain diseases and hence no longer form a connection as a chain, or one of these bones is stuck and cannot move properly.
4. Six reasons for sensorineural hearing loss:
• There could be a developmental problem in the inner ear, where the intricate system of engineering is defective from birth.
• Alternatively, it would be worn out over time simply from the aging process.
• More commonly, excessive noise damages this fragile system.
• Other things that can cause damage are viral infections and toxic chemicals from middle ear infections seeping into the inner ear. The fluid within the inner ear can leak out and this is like a leaking battery – it no longer works.
• The fluid in the inner ear causes the pressure level can go too high and this then damages the delicate structures within.
• There can be a problem with the nerve or the brain itself. This could be a tumour, or trauma that damages the nerve, or the whole range of brain problems such as a stroke or multiple sclerosis, to name two examples.
With all these potential scenarios, it is important to first identify the type of hearing loss and to investigate the different causes for such loss. This will commonly involve having a hearing test in a sound-proof booth, and potentially seeing an ENT Specialist who will then decide on further tests such as scans or blood tests. Treatments vary as to the cause and can include watchful waiting, medication and surgery, all dependant on the underlying issue.
Hearing loss can occur in any age group with serious effects.
• In children, it may affect speech and language development.
• In adults, hearing loss has been associated with increasing the risk of dementia.
Regardless of the cause, a final word of advice is not to ignore hearing loss.
The three bones in the ear are the smallest bones in the body.
Dr David McIntosh is a Paediatric ENT Specialist with a particular interest in airway obstruction, facial and dental development and its relationship to ENT airway problems and middle ear disease. He also specialises in sinus disease and provides opinions on the benefit of revision of previous sinus operations. Dr McIntosh can be contacted via this website.