5 causes of sensorineural hearing loss

Sensorineural (or nerve-related) hearing loss, is due to interference with the conversion of sound waves into an electrical signal in the inner ear, or the transmission of this signal to the brain, and the most common cause of hearing loss in adults. Here are five likely causes.

A sudden burst of intense noise, such as a gunshot, can cause transient deafness by damaging the hair cells in the cochlea. In severe cases, an acoustic trauma can lead to permanent deafness.

The most common hearing diagnosis is age-related hearing loss, known medically as presbyacusis. Here are some of the underlying factors that are thought to be linked to the problem:

• Genes. Some people seem more likely to develop hearing impairment with age than others. This could be an inherited genetic weakness, or they may be more vulnerable to other sources of hearing damage.
• Atherosclerosis. Clogged and narrowed arteries in the body mean that less blood and oxygen reach the cochlea; the resulting increase in free-radical formation damages hair cells responsible for sound detection.
• Poor diet, lack of exercise, obesity. Overeating, eating too much saturated fat or sugar, or too many junk foods causes obesity, which is linked to atherosclerosis. Lack of exercise exacerbates the problem.
• Diabetes. Atherosclerosis is accelerated in people with diabetes, who have other vascular changes that may cut blood flow to the cochlea.
• Noise. Long-term exposure to noisy environments is thought to lead to an accumulation of inner-ear damage and eventual hearing loss.
• Drugs and toxins. Many drugs can damage hearing and the chance of this increases the older we get and the more medications we are prescribed. Exposure to toxins can cause similar harm.

If a head injury, surgery or infection, such as measles, affects the inner ear, it can damage the hair cells or the auditory nerve conveying sound information to the brain, sometimes leading to a permanent hearing impairment.

• This condition can affect one or both ears. Its main symptom is sudden attacks of severe vertigo — a horrible sense of spinning and loss of balance.
• There may also be tinnitus, hearing loss and a feeling of pressure in the ear.
• Sometimes the condition runs in families, and it seems to be more common in people who suffer from migraines.
• Although the cause of Ménière's disease is not directly related to excessive salt intake, a drastic cut in salt from the diet may help symptoms to subside in some sufferers.

• Sometimes a non-cancerous tumour, known as an acoustic neuroma, grows on the auditory nerve conveying sound signals to the brain.
• This leads to hearing loss and tinnitus, headaches, dizziness and numb feelings in the face.
• Such a tumour can remain small, and its size can be monitored by regular scanning. It can be treated by surgery or radiation therapy if it shows signs of enlargement.