Age-related hearing loss
One in three people over 60 are affected by hearing loss. This can be very frustrating for sufferers, but more importantly very dangerous. The gradual loss of hearing with age is known as presbycusis, and it's causes are greatly unknown. Presbycusis is usually a sensorineural disorder, that is a disorder affecting the inner ear or the auditory nerve. It is most commonly caused by a cumulative effect of loud noises over many years leading to the loss of hair cells in the cochlea. This loss of hair cells has also been shown to have some hereditary links.
Presbycusis may also be caused by a change in blood pressure in the inner ear as a consequence of heart disease or hypertension.
Another possible cause of presbycusis may not be sensorineural at all, but infact a conductive disorder in the external or inner ear by a decrease in function of the tympanic membrane and the auditory ossicles.
The most common treatment of age-related hearing loss are hearing aids, which are worn in or behind the ear to make sounds louder.
Meniere's Disease is a disorder of the inner ear characterised by dizziness, vertigo, tinnitus and hearing loss. The cause of this disease is thought to be a change in fluid volume in the cochlea, and is named after Prosper Meniere, the French physician who first desribed the syndrome in 1861.
Speculation surrounding the exact cause of this disease suggest that an increase in endolymph inside the membranous labyrinth causes it to rupture, allowing the endolymph and the perilymph inside the bony labyrinth to mix. Scientists believe that it is this mixing which causes the symptoms described by patients, and are currently researching possible causes of this initial increase in the endolymph volume, such as environmental factors and viral infections. There is no cure for Meniere's Disease, however the symptoms can be controlled by reducing the body's fluid retention.
This is the abnormal growth of bone in the middle ear, which prevents the auditory ossicles from working effectively, sometimes leading to severe hearing loss. The type of hearing loss caused by otosclerosis depends on the particular bone affected by the disorder - it is most commonly the last bone in the series, the stapes. It causes the stapes to get stuck inside the oval window, hindering its ability to transduce sound properly to the inner ear. The main cause is thought to be hereditaty, although there has been some speculation about the involvement of some viruses such as measles. The main symptom of otosclerosis is hearing loss, which may be gradual and not recognised initally. In addition to hearing loss, some people experience dizziness and tinnitus. It is mostly treated by surgery known as a stapedectomy, which allows a prosthetic device to bypass the disease bone and allow sound waves to get to the inner ear.
As the name suggests, sudden deafness is characterised by a rapid loss of hearing, either all at once or over the course of three days. It is diagnosed if a loss of 30 dB (half the level of normal conversation) is detected in three consecutive frequencies. 9 out of 10 people are affecting in one ear only.
Some patients notice a loud "pop" just before their hearing disappears and others only realise there is a problem when they try to use that ear. Spontaneous recovery without medical intervention is very common in the first 3 days after the hearing loss, although 15% of people find that their condition worsens and the treatment they receive depends largely on the cause of hearing loss. Possible causes of hearing loss include: