Causes of hearing loss

There are many possible causes of hearing loss. These can be divided into two basic types, called conductive and sensorineural hearing loss.

Conductive hearing loss is caused by anything that interferes with the transmission of sound from the outer to the inner ear. Possible causes include:

Middle ear infections (otitis media)
Collection of fluid in the middle ear ("glue ear" in children)
Blockage of the outer ear (by wax)
Damage to the eardrum by infection or an injury
Otosclerosis, a condition in which the ossicles of the middle ear become immobile because of growth of the surrounding bone
Sensorineural hearing loss is due to damage to the pathway for sound impulses from the hair cells of the inner ear to the auditory nerve and the brain. Possible causes include:
Age or genetic inheritance.
Trauma to the ears from noise or head injury.
Viral infections as mumps or measles
Ménière's disease (abnormal pressure in the inner ear)
Certain drugs
Acoustic neuroma, a benign (non-cancerous) tumour affecting the auditory nerve
Viral infections of the auditory nerve (such as mumps and rubella)
Infections or inflammation of the brain or brain covering - e.g. meningitis
Multiple sclerosis
A brain tumour
A stroke

Treating hearing loss

The treatment of hearing loss depends on the cause. A bacterial infection of the middle ear can be treated with antibiotics; blockages of the outer and middle ears can be cleared; damaged eardrums can be repaired surgically. Some causes of sensorineural hearing loss can also be improved.

If there is no cure for the hearing loss (as with age-related hearing loss), a hearing aid for one or both ears usually helps most people, whether the hearing loss is the result of conductive or sensorineural problems. Many different types of hearing aid are available and the audiologist will advise as to which type best suits your needs.

When a hearing aid does not give sufficient amplification, as with profound deafness, a cochlear implant may help. This device transmits sound directly into the auditory nerve via electrodes surgically implanted into the cochlea.