Hearing loss is categorized into Conductive, Sensorineural, and Mixed, based on the affected ear area.
Conductive Hearing Loss
Conductive hearing loss occurs when there is a problem transferring of sounds from outer ear to inner ear. The effects of this condition makes the sounds quieter and sometimes muffled. This condition can be temporary or permanent, and often can be corrected medically or surgically.
Conductive hearing loss can be caused by following:
- Fluid in the middle ear from colds or allergies
- Ear infection (otitis media)
- Poor eustachian tube function
- Hole in the eardrum
- Too much earwax (cerumen)
- Swimmer’s ear (external otitis)
- Foreign body in the ear canal
- Malformation of the outer ear, ear canal, or middle ear
Sensorineural Hearing Loss
Sensorineural hearing loss occurs when there is damage to hair cells in the inner ear or damage to auditory nerve (or both). Most of the time, sensorineural hearing loss cannot be medically or surgically corrected
Sensorineural hearing loss can be caused by the following:
- Malformation of the cochlea or auditory nerve in the inner ear
- Exposure to loud noises, especially sudden or prolonged period of time
- Ototoxic drugs used for treatment of serious illnesses.
- Bacterial infection such as meningitis and Viral infections such as mumps
- Congenital infection such as cytomegalo virus and rubella at time of birth
- Taruma to the head
- Benign tumours such as acoustic neuroma
- Genetic factors such as connexon 26 genes
Mixed Hearing Loss
Mixed hearing loss contains elements of both Conductive and Sensorineural hearing loss, affecting the outer, middle and inner ear.