There are a number of disorders that co-occur (when multiple disorders manifest in the same person) with autism spectrum disorders (ASD). Co-occurrence of disorders can make it difficult to diagnose certain disorders and can even hamper access to appropriate treatment and interventions. Researchers from Atlanta have found that ASD have a significant rate of co-occurrence with both visual and hearing impairments. They also discovered that children who have both an autism spectrum disorder and a visual or auditory impairment tend to be diagnosed later than other children with ASD.

The researchers used data from the Metropolitan Atlanta Developmental Disabilities Surveillance Program (MADDSP), a part of a data monitoring network established by the Centers for Disease Control and Prevention. The sample included 230,000 children in Atlanta who reached age eight between 2000 and 2008. The researchers extracted data on children with poor vision (defined as trouble seeing below the third line on an eye chart) or hearing loss (being unable to follow a conversation without directly observing the speaker).

They found that six percent of the children with hearing problems (18 of 308) and seven percent of the children with visual impairments (20 of 278) also had and autism spectrum disorder. Only one percent of the general population has ASD. They also discovered several trends: more boys have hearing loss and ASD (15 total) than girls (three total); children with co-occurring ASD and sensory impairments were more likely to be born early and have a low birth weight; and children with both hearing loss and autism were more likely to have cerebral palsy and intellectual disability.

Notably, the evidence indicated that children with visual impairments are diagnosed two years later on average than normally sighted peers. Many tests for ASD rely on skills like making eye contact, which is problematic for children with visual impairments. Late diagnosis leaves children without appropriate early interventions. Part of the problem for diagnosis may stem from the fact that some behaviors that are typically considered the hallmarks of ASD, like rocking, are also associated with visual impairments in children. Doctors may be attributing such behaviors to a sensory impairment, rather than autism, leading to mis- or late diagnosis.

This study may have implications for how children with visual or hearing impairments are diagnosed and treated. According to the study’s principal investigator, Kim Van Naarden Braun, “[the study] underscores the need for the development of additional tools and awareness for the co-occurrence.”

This research is published in Disability and Health Journal.

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