Causes of hearing loss
There are many possible causes of hearing loss, which can be divided into two main groups 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. Below are some possible causes of conductive hearing loss.
- Middle ear infections (otitis media).
- Collection of fluid in the middle ear (“glue ear” in children)..
- Blockage of the outer ear, most commonly caused by wax.
- Otosclerosis, a condition in which the ossicles (tiny bones)of the middle ear lose mobility.
- Perforated eardrum, which can be caused by an untreated ear infection, head injury or trauma to the ear.
Sensorineural Hearing Loss (sometimes called nerve deafness) usually means that there is a problem in the part of the inner ear called the cochlea, impairing the transmission of sound impulses to the auditory nerve and the brain. Below are some possible causes.
- Age-related hearing loss (presbyacusis). This is the natural decline in hearing that many people experience as they get older. It’s partly due to the loss of hair cells in the cochlea.
- Acoustic trauma (injury caused by loud noise) can damage hair cells.
- Certain viral or bacterial infections such as mumps or meningitis can lead to loss of hair cells or other damage to the auditory nerve.
- Ménière’s disease, which causes dizziness, tinnitus, and hearing loss.
- Certain drugs, such as some powerful antibiotics, can cause permanent hearing loss. At high doses, aspirin is thought to cause temporary tinnitus – a persistent ringing in the ears. The antimalarial drug quinine can also cause tinnitus, but it’s not thought to cause permanent damage.
- Acoustic neuroma. This is a benign (non-cancerous) tumour affecting the auditory nerve. It needs to be observed and is sometimes treated with surgery.
- Other neurological (affecting the brain or nervous system) conditions such as multiple sclerosis, stroke, or a brain tumour.
Mixed hearing loss is a combination of conductive and sensorineural hearing loss.