Types and Causes of Hearing Loss
The type of hearing loss in any one person depends upon where in the ear the problem occur. The three main types are conducive, sensorineural, and mixed losses.
Conductive: A problem in the outer or middle ear causes conducive hearing loss. A conductive loss prevents sound from reaching the nerves in the inner ear. Common causes include:
- Conditions associated with middle ear pathology such as fluid in the middle ear from colds, allergies, poor eustachian tube function, ear infection, perforated eardrum, benign tumors
- Impacted earwax
- Infection in the ear canal
- Presence of a foreign body
- Absence or malformation of the outer ear, ear canal, or middle ear
Sensorineural: Damaged nerves in the inner ear cause senorineural hearing loss. Sensorineural losses cannot be reduced or eliminated by surgery. There are many causes, differing by age of onset.
Before or During Birth:
- Perinatal infections such as rubella, herpes, toxoplasmosis, syphilis, cytomegalovirus (CMV)
- Asphyxia or lack of oxygen at birth.
- Possible association with birth weight of less than 1500 grams.
- Possible association with defects of the head and neck
- Bacterial meningitis
- Ototoxicity (drug induced)
- Intense or excessive noise
- Physical damage to head or ear
Mixed: Sometimes, people will have problems both in the inner ear and in the outer or middle ear. This type of hearing loss is known as a mixed loss.