How is Usher syndrome diagnosed?
Usher syndrome is diagnosed based on hearing, vision and balance tests. Testing for the Usher gene can confirm the diagnosis but usually is not necessary. Genetic testing for the different types of Usher syndrome is available at several laboratories nationwide.
- Virtually all infants born in the United States have a hearing screen at birth.
- Babies who do not pass the newborn hearing screening should have a follow up hearing test to evaluate for hearing loss. Based on additional signs and symptoms, genetic testing may be done to find out if they have an Usher syndrome gene.
- Older children, teens or young adults with hearing loss should undergo an audiology evaluation. This exam measures how loud a sound needs to be before it is heard.
- Usher syndrome may go undiagnosed until the child (or the parents) notice night vision loss. This loss:
- Occurs before age 10 in type 1.
- Occurs during teenage years in type 2.
- Testing includes:
- Physical examination of the retina. The exam can detect changes in blood vessels, a waxy look to the retina surface, and clumps of dead retinal cells (bone spicules).
- Visual field testing. This test measures peripheral (side) vision.
- Electroretinogram (ERG). This exam confirms the diagnosis of retinitis pigmentosa and also the retina's response to light. Because the test requires the insertion of a contact lens, general anesthesia is used with young children.
- Electronystagmogram (ENG) measures involuntary eye movement, which can detect balance problems.