Hearing Impairment
The two most common types of hearing loss are sensorineural and conductive.
A sensorineural loss is hearing loss "caused by damage to some or all of the nerves in the inner ear. Sensorineural losses cannot be reduced or eliminated by surgery." The causes of sensorineural loss range from heredity to infections at birth or intense noise or damage to the ear.
Conductive loss is hearing loss "caused by a problem in the outer or middle ear. A conductive loss prevents sound from reaching the nerves in the inner ear." Common causes can include a ruptured eardrum problem with the outer or middle ear structure or fluid or wax buildup. (Laurent Clerc National Deaf Education Center Gallaudet University)
Statistics
Over thirty-five million people over the age of 18 reportedly have hearing difficulties based on 2004 survey data from the National Center for Health Statistics (Lethbridge-Cejku, Rose & Vickerie, 2006).
Accessibility and Hearing Impairment
The use of sound and multimedia on the Web presents a challenge to individuals with hearing impairments. Processes that are similar for captioning television apply to the captioning of Web video. The National Center for Accessible Media has been very instrumental in supporting the production of accessible Web based video.
Resources
For more information on hearing impairments:
- Lethbridge-Cejku, M., Rose, D. & Vickerie, J. (2006). Summary Health Statistics for U.S. Adults: National Health Interview Survey, 2004. National Center for Health Statistics. Vital and Health Statistics 10 (228). Available at http://www.cdc.gov/nchs/data/series/sr_10/sr10_228.pdf
- WebAim. Auditory Disabilities: at http://www.webaim.org/articles/auditory/
- Laurent Clerc National Deaf Education Center Gallaudet University. Support Services Handout Series Number 5001 Audiology Sheet About Hearing Loss. Available at http://clerccenter.gallaudet.edu/SupportServices/series/5001.html
