Characteristics of Usher's Syndrome
The Most Common Medical Condition Affecting Both Hearing and Vision
Apr 9, 2009
“Usher Syndrome is the most common condition that affects both hearing and vision. United States, about four babies in every 100,000 births have Usher syndrome,” says JD Eudy and J. Sumegi in the October 15th 1999 Cell Mol Life Science article entitled “Molecular genetics of Usher syndrome.” Also, approximately 3-6% of all deaf children and perhaps another 3-6% of hard-of-hearing children have Usher Syndrome.
Higher than normal numbers of people with Usher's Syndrome have been found among Jewish people in Berlin, Germany; French Canadians of Louisiana; Argentineans of Spanish descent; and Nigerian Africans. (National Institute on Deafness and Other Communication Disorders Population Estimates, 2008).
Symptoms of Usher Syndrome
The major symptoms of Usher syndrome are hearing loss and an eye disorder called retinitis pigmentosa, or RP. RP causes night-blindness and a loss of peripheral vision through the progressive degeneration of the retina.
As RP progresses, the field of vision narrows—a condition known as “tunnel vision”—until only central vision remains. Many people with Usher syndrome also have severe balance problems.
Special tests such as electronystagmography (ENG) to detect balance problems and electroretinography (ERG) to detect retinitis pigmentosa help doctors diagnose Usher Syndrome.
Usher syndrome is inherited as an autosomal recessive trait. The term autosomal means that the mutated gene is not located on either of the chromosomes both males and females can have the disorder and can pass it along to a child. The word recessive means that, to have Usher syndrome, a person must receive a mutated form of the Usher syndrome gene from each parent.
Characteristics of the Three Types of Usher Syndrome
Children with type 1 Usher syndrome are profoundly deaf at birth and have severe balance problems. Many of these children obtain little or no benefit from hearing aids. Intervention should be introduced early, during the first few years of life, so that the child can take advantage of the unique window of time during which the brain is most receptive to learning language, whether spoken or signed.
If a child is diagnosed with type 1 Usher syndrome early on, the child is more likely to benefit from the full spectrum of intervention strategies that can help him or her participate more fully in life's activities.
Due to the balance problems associated with type 1 Usher syndrome, children with this disorder are slow to sit without support and typically don’t walk independently before they are 18 months old(Eudy, Sumegi).
Type I Usher's Syndrome is characterized by vision problems beginning at approximately the age of ten, development of night blindness at approximately twenty years of age, and progressive loss of peripheral vision (Eudy, Sumegi).
On the other hand, children with type 2 Usher syndrome are born with moderate to severe hearing loss and normal balance. Although the severity of hearing loss varies, most of these children can benefit from hearing aids and can communicate orally. The vision problems in type 2 Usher syndrome tend to progress more slowly than those in type 1, with the onset of RP often not apparent until the teens.
Children with type 3 Usher syndrome have normal hearing at birth. Although, hearing and sight worsen over time. A person with type 3 Usher syndrome may develop hearing loss by the teens, and he or she will usually require hearing aids by mid- to late adulthood. Night blindness usually begins sometime during puberty. Blind spots appear by the late teens to early adulthood, and, by mid-adulthood, the person is usually legally blind.
Currently, there is no cure for Usher syndrome. Early diagnosis is important in order to begin special education training programs. Typically, treatment will include hearing aids, assistive listening devices, cochlear implants, or other communication methods such as American Sign Language; orientation and mobility training; and communication training which may include Braille instruction or auditory training.
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