Often, children with autism have difficulties developing motor skills, such as throwing a ball, learning how to write, or running. However, a study published in the journal Autism, suggests that autism itself, not genetics, may be to blame. The research was conducted at Washington University School of Medicine in St. Louis.
Claudia List Hilton, Ph.D., lead researcher of the study, assistant professor in occupational therapy and an instructor in psychiatry, explained:
"From our results, it looks like motor impairments may be part of the autism diagnosis, rather than a trait genetically carried in the family. That suggests that motor impairments are a core characteristic of the diagnosis."
144 children from 67 families, in which at least one child had a diagnosis of autism spectrum disorder, in addition to at least one biological sibling in the same age group, were enrolled to participate in the study. 48 of the families had only one child with the disorder, and 29 had two children with the disorder, including six identical twins.
The study is the first to assess motor impairments in children with autism, and their siblings without the disorder, as well as the association between motor impairment and the severity of the disorder.
Using a standardized measure of motor proficiency, commonly used in children with disabilities that measures strength, agility, fine manual control, body coordination, and manual control, the researchers asked participants to perform a variety of motor skills, including, push-ups, cutting with scissors, running, imitating movements, placing pegs in a pegboard, copying forms and throwing a ball.
The team, including co-author John Constantino, M.D., found that 83% of children with the disorder scored below average in motor skills, compared with only 6% of their siblings without the disorder. Siblings without the disorder generally scored in the normal range.
Furthermore, the researchers found:
- The scores for siblings in which one child had autism and other did not, were very different.
- Identical twins had very similar scores.
- Scores were very similar among siblings who each had the disorder.
"The data suggests that genes play a role in the motor impairments observed in those with autism spectrum disorder. This is further evidence that autism spectrum disorder is a largely genetic disorder."
Co-author Constantino, the Blanche F. Ittleson Professor of Psychiatry and Pediatrics and director of the William Greenleaf Eliot Division of Child and Adolescent Psychiatry at Washington University, said:
"It's possible that developmental processes in the brain which give rise to motor coordination and social responsiveness are shared by both systems. This could explain their association in autism and provide new ideas about intervention strategies to help affected children, such as innovative methods for promoting motor development."
Results from the study indicated that the lower the motor proficiency score in children with the disorder, the greater the severity of the disorder and the degree of social impairment.
"Kids who have difficulty with motor skills might have trouble with what we think are simple things like brushing their teeth, buttoning, snapping or starting a zipper - things that are so basic to being independent, but would cause other problems at school. They would need to have an aide or someone helping them, and that would set them off as different from the other kids."
According to Hilton, these impairments can result in larger problems in the future.
"Some kids aren't socially aware enough that it bothers them, but others are aware, and they feel bad about themselves. They may have love self-esteem, so even if they have delays only in the motor skills, there is a lot of impact on their wellbeing into adulthood."
Written by Grace Ratue