There is evidence to suggest that hearing and listening difficulties often co-exist with other neurodevelopmental conditions. This means that if a child has challenges with the growth and development of their brain or central nervous system, they may also have hearing impairment. Understand the correlation between autism and deafness.
This suggests that autism and deafness can be a dual diagnosis in a substantial number of cases. Putting an exact figure on this is difficult.
The deafness would generally be the first medical condition to be diagnosed. All babies are routinely tested for hearing abilities, so genetic and birth defects are identified early. Childhood illnesses and infections that result in deafness would also be noticeable.
Hearing impairment at any level in childhood would bring with it communication problems and development delays. This makes finding sufficient evidence for a diagnosis of autism may take some years.
This situation is further complicated by the fact autism is not always easy to identify, even in children with no hearing deficit. There are no blood tests or scans that can detect the traits that suggest a child has this medical condition.
There is also no known cause and its impact can vary hugely from child to child. The medical professional generally maintains that autism becomes more tangible from the age of three years.
All children develop at their own pace and in their own way. Many children display behavior issues or specific development delays during those early years. The challenge for physicians and parents is to know when these symptoms and delays are at a level to attach a diagnosis of autism to the child.
All three of these would have to be present – at a clearly discernible level - for a diagnosis of autism.
The child’s ability to carry out tasks, their fine motor skills, coordination, and intellect are not factors. A child or an adult with autism may well be functioning at a high level, and may even be intellectually advanced.
Autistic spectrum disorder is the diagnosis given to a child whose assessment shows evidence of one or two of the above criteria, or tendency towards all three.
In recent times, Asperger's Syndrome has been added to autistic spectrum. This is a developmental disorder in the way children see the world and their abilities to form relationships.
Children with autism sometimes find sound challenging and too much noise confusing and distressing. Children with severe autism will also find it difficult to respond appropriately to audio tests for hearing ability. This means that if deafness is not picked up early, in some cases a delayed diagnosis may only be possible by physical examinations.
Children with hearing and speaking problems may not develop as quickly as their peers. They will certainly have difficulties with both communication and social interaction. If they are profoundly deaf, the world could seem a bewildering place, and they may seek solace in repetitive behaviors.
This means that they may well tick all the boxes for autism, when in fact it is their deafness, not this neurological condition that is affecting their behavior and development.
That said, there does appear to be a higher incidence of autism spectrum disorder in deaf children than in hearing children.
The connection between autism and deafness becomes even more pronounced when hearing impairment results from damage to brain tissue, for example, due to meningitis, rubella or prematurity. This is a logical correlation. Though the cause of autism is not known, it does appear to be a deficit in neurology (brain function).
Receiving a dual diagnosis can mean that parents and other caregivers have a particularly difficult road ahead of them. Support systems to cope with such a profound communications void are in their infancy.
Teaching a child sign language when they are unresponsive, or even when they have poor social interaction, is never going to be straightforward. However, it is possible.
In one study, children with both autism and deafness were observed. One of the interesting findings was that they signed in a reverse direction. It appears to show that the altered perceptions of someone with autism could lead them to mirror actions, rather than interpreting them appropriately.
There was another interesting thing to emerge from this study. Just as verbal autistic children avoid pronouns (such as you, he and she) deaf autistic children signed proper names and avoided signs for pronouns. This supports the theory that many autistic children find comfort and structure in having a distinct separate name for all things.
The correlation between autism and deafness requires more research. Methodology to support children with a dual diagnosis is also needed.
This work may also shed some light on the mystery that surrounds why some autistic children never develop the ability to speak. It's estimated that as many as 30% of children with autism can hear, but never talk.
Research into the connection between autism and deafness may also uncover important insights.
Studies in this field may also add to efforts to encourage more hearing children with autism to become fully converse in American sign language to overcome their speech deficit.