- Sensory hearing loss. This occurs when the inner ear is damaged, most commonly from aging, inner ear infection and noise exposure. It is usually not medically or surgically treatable. Most people with a sensory hearing loss find that hearing aids are beneficial.
- Neural hearing loss. This type of loss occurs when the hearing nerve or the nervous system is damaged. Again, this can be caused by aging, in which case hearing aids may help. Or it may be caused by a tumor, such as an acoustic neuroma, pressing on the hearing nerve. This can sometimes be surgically treated.
- Conductive hearing loss. Conductive hearing loss occurs when the outer or middle ear fails to work properly. Sounds become "blocked," often by fluid, wax or problems with the small bones of the middle ear, and are not carried to the inner ear. These losses are often treatable with medicine or surgery. Sometimes conductive hearing loss occurs when the eustachian tube, which opens to the back of the nose, fails to drain fluid properly due to inflammation. This can usually be corrected.
- Unilateral deafness. People with unilateral or single-sided deafness have complete hearing loss in one ear and normal or near-normal hearing in the other ear. Following a medical evaluation to determine if there is a serious underlying cause, people with unilateral hearing loss can often be helped with the contralateral routing of signals (CROS) hearing devices or the bone-anchored hearing aid (Baha system).