Hearing Loss

According to The Royal National Institute for Deaf People, there are nearly 9 million deaf and hard of hearing people in the UK, 2 million of them between 16 and 60.

There are many reasons for loss of hearing, some are directly linked with medical conditions, some are caused due to our lifestyle choices and some are age related, but what can we do to ease or prevent them?

There are many different types of hearing loss, depending on which part of the hearing pathway is affected. An otologist (ear specialist) will locate the source of the hearing loss, in order to classify it into one of the following groups:

Conductive hearing loss

Any condition that interferes with the transmission of sound through the outer and middle ear to the inner ear. This can be anything from fluid in the Eustachian tube, leading to lessened mobility of the eardrum, the tiny bones inside the middle ear or a blockage in the middle-ear cavity.

Common causes are:

• Ear Wax
• Infections which swell or produce fluids
• Foreign bodies in the ear
• An injury, such as a sports injury
• ·Birth defects
• Otosclerosis, where new bone is deposited around one of the tiny bones in the middle ear, preventing transmission of sound. This can cured by a surgical procedure called stapedectomy, in which the bone is replaced by an artificial bone.

Conductive hearing loss can be cured medically or surgically, often using a procedure called myringotomy, which pierces a small hole in the ear drum, and patients can greatly benefit from hearing aids as what is needed most is amplification.

Sensorineural hearing loss
The damage lies inside the inner ear, the acoustic nerve, or both. With over 30, 000 nerve endings the cochlea is susceptible to damage from a variety of causes. This form of hearing loss is the most challenging to correct, but some people experience dramatic improvements.

There are many conditions that cause the delicate inner portion of the ear to function abnormally.

They include:
Otosclerosis
Infections
Presbycusis, the natural aging process, causing damage to both the inner ear, the acoustic nerve, or both. Shortly after birth, we begin to lose hair cells and nerve endings within the cochlea, and the stiffening of the cochlea and loss of nerve endings is also detrimental.
Trauma, such as a blow to the ear or a head injury, can cause a fistula, or opening, to develop. The inner ear is filled with fluid, and the middle ear is filled with air, causing hearing loss and dizziness if fluid leaks through. This kind of hearing loss often is cured by surgically repairing the fistula.

One of the biggest, and most discussed, causes of sensorineural hearing loss is noise. Whether that be through industrial noise or recreational, it can cause significant damage to hearing. While loud rock music through headphones is most frequently blamed, gunfire, power tools and classical musical instruments such as the violin can all damage hearing. Continuous exposure to loud noise damages the structure of hair cells, resulting in hearing loss and tinnitus, although the process occurs more gradually than for impulse noise, where a unexpected extreme noise, such as an explosion, causes immediate hearing loss. In most cases there is very little that can be done after impulse noise damage, as the damage is so extensive.

Central hearing loss
An inability to filter out competing sounds, such as hearing a conversation in a busy room, or missing the beginning of a sentence because you are not looking at the person and therefore your brain cannot fill in the gaps. In this instance physical ‘hearing' is not the issue, it is understanding what is being said that is the problem due to an issue with the central nervous system. This has previously led to miss-diagnosis, but now it is recognised by otologists, and whilst treatment is limited a lot can be achieved by educating the person, their family and friends.

Functional hearing loss
Again there is no physical damage to the hearing process, however the hearing loss is due to a psychological or emotional problem: they do not seem to hear or respond. This poses a challenge for otologists not only in terms of diagnosis but also treatment: which can result in further emotional trauma.

Mixed hearing loss
Occurs when both conductive and sensorineural hearing losses are present in the same ear, making treatment complicated but not impossible.

In most cases of mild to moderate hearing loss your GP or otologist will recommend a hearing aid. Over two million people in the UK use hearing aids, which are in essence micro-computers which suppress background noise, and come in a variety of models. See panal for a guide to hearing aids.Guide to hearing Aids

Four main models exist and the suitability of each type will depend on factors such as degree of hearing loss and physical dexterity.

1) Behind-the-ear (BTE)
This device is housed in a small case behind the ear and the sound is delivered into the ear canal via a custom-made earmould or tubing system. BTE designs have become smaller and smaller over the years, and the introduction of receiver into the canal has been a recent development.

2) In-the-ear (ITE)
ITEs are completely contained in a custom-made casing that fits into the pinna. They are easy to handle, give reasonable easy access to controls, but they are sometimes visible when standing face to face with someone.

3) In-the-canal (ITC)
ITC aids are smaller, filling only the bottom half of the external ear, giving them a cosmetic appeal.

4) Completely-in-the-canal (CIC)
CICs are considered to be modern and cosmetically appealing as they fit so deep in the ear canal that they are practically invisible.

With thanks to www.nidcd.nih.gov, www.ehealthmd.com, Baby boomers and hearing loss: a guide to prevention and care by John M. Burkey and Joan McKechnie at Hearing Direct,
www.hearingdirect.com.