The Ways Hearing Can Go South

The annual National Audiology Awareness Month is recognized each October. One of the many things hearing health professionals do is examine people who have realized that their hearing is not functioning at the level they expect. At this preliminary stage, it is required to broadly diagnose what kind of hearing loss is being manifested.

The field uses four comprehensive classes of hearing loss when treating someone. These are sensorineural, auditory processing, conductive, and mixed hearing loss.

The first type, sensorineural, is due to damage to the inner ear or the nerve transmitters that send electrical signals to the brain. The performance of either the cochlea (which is the part of the ear that creates nerve impulses from the sound waves that have been processed by other parts of the ear) or the vestibulocochlear nerve (the communication conduit between the ears and the brain) — or both — have degraded in some way. Aging and long-term exposure to excessive sound are the most likely culprits in adults and hearing aids are the most common treatment.

When there is a breakdown between ears that are functioning correctly and the part of the brain that receives electrical inputs via the vestibulocochlear nerve, it is known as an auditory processing disorder. More common in children — about 5 percent of school-age kids suffer from it — it is not completely understood but has been linked to ear infections, head trauma, and premature birth. A wide range of treatments are combined to deal with individual situations.

The simplest type is conductive hearing loss; something’s just gotten in the way. It could be earwax, swelling of the ear’s walls or other organs, or an infection or allergies that have filled the ear canal with fluid. In rare circumstances, a benign tumor (fibrous dysplasia) or injured eardrum is the culprit. Depending on the issue, medical treatment usually solves the problem, but in some cases hearing aids are needed as a work-around.

Finally, the aptly-named mixed hearing loss is the category for some combination of the above three classifications.