ABSTRACT
Sensory impairment primarily involves vision and hearing, also in combination with each other. Milder impairments of vision and hearing can be difficult to detect, especially as children have no way of knowing how other children see and hear. Early diagnosis is important for the creation of an environment that provides the children with access to experiences that allow them to establish social relations and create meaning based on their own perceptual abilities. An important distinction is that between prelingual and acquired hearing loss. Hearing loss after children have developed spoken language has other developmental consequences than hearing loss that is congenital or occurs before speech has evolved. The cause is often unknown and may be related to genetic factors, prenatal infections, substance abuse by the mother or a number of different syndromes. About 5 percent of all children with profound hearing loss have Usher syndrome, which leads to the eye disorder retinitis pigmentosa as well as problems with balance.
