Hearing loss typically produces a decrease in the detection and understanding of sound, particularly under challenging listening conditions such as background noise. The perception of both simple and complex sounds (e.g. speech and music) can be affected. Hearing loss may be associated with different types of health problems. There are two basic types of hearing loss:
Conductive Hearing Loss – occurs when sound cannot travel efficiently through the ear canal, ear drum or middle ear. Some of the primary, or common causes of conductive hearing loss include:
- Obstruction of the ear canal by ear wax or a foreign object
- Perforation or other damage to the ear drum
- Acute or chronic middle ear infections
- Injury/diseases affecting the small bones inside the middle ear
Conductive hearing loss is often reversible with medical or surgical treatment. If the hearing loss cannot be corrected then hearing aids are usually appropriate.
Sensorineural Hearing Loss – occurs when there is damage to the inner ear (cochlea) or auditory nervous system in the brain. Some of the common causes of sensorineural hearing loss are:
- Excessive exposure to loud noise
- Viral or bacterial infections
- Medications such as certain types ofantibiotics (gentamycin, streptomycin, erythromycin and vancomycin), ASA, and certain drugs given for the treatment of cancer (cisplatinum)
- Meniere’s Disease – an inner ear disorder which produces fluctuating hearing loss, periods/attacks of vertigo (dizziness), full feeling in the ears and tinnitus (ringing/buzzing in the ears)
- Gradual age-related hearing loss called presbycusis (affects 30% of persons over the age of 65)
- Acoustic Neuroma a tumor located between the ear and the brain and which usually affects balance as well as hearing.
Sensorineural hearing loss is a permanent type of hearing loss that usually can be helped with a hearing aid or other type of assistive listening device.
A Mixed Hearing Loss occurs when someone has a combination of a conductive and a sensorineural hearing loss.