Causes of Deafness
To determine the causes of deafness, one must establish the types of hearing loss. There are two main categories of hearing loss:
- Conductive
- Neural (or nerve deafness)
Conductive Hearing Loss
“Conductive hearing loss occurs when sound vibrations don’t go from the air around a person to the moving bones of the inner ear as well as they should.” This can be caused by earwax buildup, fluid retention such as an ear infection, or calcium buildup.
“Generally, conductive hearing loss doesn’t cause a total inability to hear, but it does cause a loss of loudness and a loss of clarity. In other words, sounds are heard, but they are weak, muffled, and distorted.”
"d-e-a-f" spelled in sign language
Neural Hearing Loss
“Neural hearing loss (Nerve deafness) occurs when the auditory nerve, which goes from the inner ear to the brain, fails to carry the sound information to the brain. Neural hearing loss can cause a loss of loudness or a loss of clarity in sounds.” Some people may also experience a mix of both conductive and neural hearing loss.
Ranges of Hearing Loss
“Deafness can range from mild to profound and the causes of deafness can include a multitude of events including injury, disease, and genetic defects.” Hereditary and Genetic disorders, parental exposure to disease, noise, trauma, and disease are some causes that may lead to permanent hearing loss. Some causes of temporary deafness include wax, foreign object, excess mucus, ear infections, and certain types of drugs such as aminoglycosides and chloroquine.
Age & Noise are the Leading Causes of Deafness
Although age is the most common reason for deafness, some individuals are born with partial and total hearing loss. Deafness at birth is known as congenital deafness, while deafness that occurs after birth is called adventitious deafness. The most common cause of adventitious deafness is noise, which accounts for over one quarter of people affected by hearing loss.
Sources Include
http://library.thinkquest.org/15390/causes.htm
http://library.thinkquest.org/15390/causes.htm
http://library.thinkquest.org/15390/causes.htm
http://www.betterhealth.vic.gov.au/bhcv2/bhcArticles.nsf/pages/Deafness_-_a_range_of_causes?OpenDocument
http://www.betterhealth.vic.gov.au/bhcv2/bhcArticles.nsf/pages/Deafness_-_a_range_of_causes?OpenDocument