The general types of hearing loss can be described as congenital or acquired. A congenital hearing loss is one that is present at, or soon after, birth. An acquired hearing loss is one that occurs later on in life. Depending on which part of the hearing system is affected, hearing loss is categorised as conductive, sensorineural or a mixture of both.
Conductive hearing loss
Conductive hearing loss is caused by blockage or damage in the outer ear, middle ear or both. It leads to a loss of loudness. Some of the causes of a conductive hearing loss include ear infections, perforated eardrum or blockage of the ear canal by wax or foreign objects. The degree of a conductive hearing loss varies, but you cannot go completely deaf. A conductive hearing loss can often be treated by medical or surgical means.
Sensorineural hearing loss
This is a result of damage to, or a malfunction of, the cochlea (the sensory part) or the hearing nerve (the neural part). It results in a loss of loudness as well as a lack of clarity. It can be caused by the ageing process, excessive noise exposure, diseases such as meningitis or Meniere’s disease, and viruses such as mumps or measles. There is rarely any medical treatment for sensorineural hearing loss, so it is permanent and hearing devices are often recommended.
Mixed hearing loss
A mixed hearing loss is caused by problems in both the conductive pathway (in the outer or middle ear) and in the nerve pathway (the inner ear). An example of a mixed hearing loss is a conductive loss due to a middle-ear infection combined with a sensorineural loss caused by ageing.