Deafness (hearing impairment)

Deafness is a condition wherein the ability to detect certain frequencies of sound is completely or partially impaired. When applied to humans, the term hearing impaired is rejected by the deaf culture movement, where the terms deaf and hard-of-hearing are preferred. Pre-lingual deafness Prelingual deafness is hearing impairment that is sustained prior to the acquisition of language, which can occur as a result of a congenital condition or through hearing loss in early infancy. Prelingual deafness impairs an individual's ability to acquire a spoken language, but children born into signing families rarely have delays in language development. Most pre-lingual hearing impairment is acquired via either disease or trauma rather than genetically inherited, so families with deaf children nearly always lack previous experience with sign language. Post-lingual deafness Post-lingual deafness is hearing impairment that is sustained after the acquisition of language, which can occur as a result of disease, trauma, or as a side-effect of a medicine. Typically, hearing loss is gradual and often detected by family and friends of affected individuals long before the patients themselves will acknowledge the disability.[citation needed] Common treatments include hearing aids and learning lip reading. Post-lingual deafness is far more common than pre-lingual deafness. Unilateral and bilateral hearing impairment People with unilateral hearing impairment (single sided deafness/SSD) have an impairment in only one ear. This can impair a person's ability to localize sounds (e.g., determining where traffic is coming from) and distinguish sounds from background noise in noisy environments. A similar effect can result from King-Kopetzky syndrome (also known as Auditory disability with normal hearing and obscure auditory dysfunction), which is characterized by an inability to process out background noise in noisy environments despite normal performance on traditional hearing tests. See also: "cocktail party effect", House Ear Institute's Hearing In Noise Test.


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607371 dystonia juvenile-onset (DYTJ) ACTB deafness (hearing impairment) chromatin remodeling
604717 deafness autosomal dominant type 20 (DFNA20) ACTG1 deafness (hearing impairment) Deafness, autosomal dominant 20/26
dominant deafness type 26
chromatin remodeling
613398 Warsaw breakage syndrome (WBRS) helicase DDX11 (CHLR1) microcephaly, skin problem, chromosomal instability, facial anomalies, growth retardation, deafness (hearing impairment) WBR syndrome
WBRS syndrome
WBRS DNA replication
610131 progressive external ophthalmoplegia with mitochondrial DNA deletions autosomal dominant type 4 (PEOA4) POLG2 deafness (hearing impairment), eye or vision problem PEOA4 DNA replication

Last modification date: Aug. 17, 2011