Sensory impairments, intellectual disability and psychiatry.

The present review looks at: (1) prevalence studies of sensory impairments in people with intellectual disability (ID); (2) studies looking at psychological and psychiatric disorders in people with sensory impairments; and (3) studies that have examined the association of sensory impairments with autism. Research has indicated that sensory impairments are more common in people with ID. Psychiatric disorders are believed to be more common in children with visual impairment (VI) when associated with other handicaps. Some authors believe that hearing impairment (HI) can result in personality disorders. Studies have also shown a higher prevalence of psychiatric disorders in children with HI and a higher incidence of deaf people in psychiatric hospitals than in the general population. Psychiatric disorders in children with HI are particularly associated with low IQ and low communication ability, especially in those with multiple handicaps. There is little evidence for a higher incidence of schizophrenia in people with HI. Blind people demonstrate many autistic-like features and there has been discussion in the literature as to their cause. Deaf people also demonstrate some similar features to those in autism, but an association with autism has not been conclusively made. Deaf-blind people commonly demonstrate problem behaviour (e.g. self-injury). Usher syndrome, which is the most common cause of deaf-blindness, is associated with psychiatric disorders, particularly psychosis. The need for assessment of sensory functioning in people with ID, the difficulties inherent in this and the need for specialist services is stressed.