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Deafness can be caused by a wide range of factors. While genes can cause deafness (and can make deafness hereditary), they are thought to cause only a small number of people to become deaf. To get information on some of the causes of deafness, scroll down, or click on one of the following links.
For a more complete list, visit this page from Gallaudet University.
Diseases (Click one for more information)
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Prenatal exposure to disease and toxins
Babies can lose their hearing if they are exposed to certain diseases in utero, including rubella (German measles), influenza, herpes, syphilis and mumps.
Consuming alcohol, medications, or other toxins while pregnant may also cause deafness.
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Genetics
Genetic mutations may also cause deafness. Each person is born with 100,000 genes. For most people these are all nearly the same. Differences in the gene sequence are called genetic mutations. Sometimes these have no effect on someone's health. Mutations on certain genes can cause deafness.
Genes are inherited from a child's parents. This is usually due to the existence of one dominant mutated gene or two recessive mutated genes. Sometimes genetic deafness becomes present even though there is no history of family deafness. This can be due to recessive genes, or a genetic mutation in the father's sperm cell or the mother's egg cell.
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Physical malformations
If any of the physical structures necessary for the transmission of sound is not properly formed, some degree of deafness may result. These structures include the ear canal, ear drum, ear bones, as well as the inner ear.
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Trauma
Perforation of the eardrum, fractured skull or severe changes in air pressure can cause deafness.
The auditory nerve can also be damaged from injuries, such as auto accidents or falls. The result of nerve damage is that the electrical signals of sounds do not get transmitted from the ear to the brain.
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Age-related Hearing loss
Age-related hearing loss normally starts with the loss of higher frequencies of sound. This can cause some words to sound very similar. This means the older person can hear, but not always understand what is being said.
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Drugs
Certain drugs have side effects that can cause temporary deafness in susceptible people.
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Foreign objects
A foreign object stuck inside the ear canal (such as the tip of a cotton bud) can cause deafness.
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References:
Frangulov, Anna, Heidi Rehm, and Margaret Kenna. Common Causes of Hearing Loss: For Parents and Families. Harvard Medical School Center for Hereditary Deafness: 2004.
Rehm, Heidi, et. al. Understanding the Genetics of Deafness: A Guide for Patients and Families. Harvard Medical School Center for Hereditary Deafness: 2003.
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