The Missing Link
Most everyone knows the classic symptoms of autism: poor communication and difficulty interacting with others. Most treatment and research efforts focus on these deficits, but another area of concern is motor skill development. In a new study at Kennedy Krieger Institute, scientists are attempting to better understand the cause of motor deficits in children with autism, which they believe is a critical component in solving the mystery of the neurological basis of autism.
Dr. Stewart Mostofsky is leading the study exploring why children with autism have trouble learning to perform activities like riding a tricycle and putting a key in a lock. "And even when they sit up or walk at the expected time, they tend to reach those milestones in atypical ways," he says. He is interested in learning whether there is any link between these motor deficits and the socialization and communication problems that characterize the disorder.
Dr. Mostofsky's study is based on the understanding that there are two forms of learning: declarative and procedural. Declarative learning centers on memorization of facts; procedural learning refers to the learning of skills through repeated exposure to and practice of behaviors. He believes that the motor deficits linked to autism are caused by problems children with autism have with procedural learning, and that impaired procedural learning may also help to explain the social skill and communication skill deficits that characterize autism.
"There's a clear overlap between the regions of the brain that involve motor imitation and those regions involved in language production," he says. "A large part of communication involves physical gestures, which we probably learn through procedural means tied to imitation. Children with autism typically have problems with communication that include not only problems with language, but also problems with learning nonverbal communicative gestures, such as pointing and waving good-bye. Furthermore, motor imitation is thought to be important in the development of social awareness, because we often learn to guess what other people are thinking and feeling based on how we think and feel when we act the same way."
Funded by a two-year, $120,000 grant from the National Association for Autism Research, the study calls for the recruitment of 25 children between the ages of eight and 12 with high-functioning autism and Asperger's syndrome, as well as 25 typically developing control subjects. The team will observe the children as they perform a battery of motor skill assessments. In addition, the children will receive functional magnetic resonance imaging scans of their brains as they perform additional motor tasks. The scans will show Dr. Mostofsky and his colleagues how activation of brain regions differs in children with autism. "Knowing where abnormalities lie helps us establish the neurological basis of the deficits," Dr. Mostofsky says.
Finding out more about the basis of autism can help direct treatment efforts. "One of the most common therapeutic approaches for children with autism is applied behavior analysis, where a therapist explicitly instructs a child to perform a task, after which the child is rewarded," Dr. Mostofsky says. "This approach appears to rely on declarative instruction to teach skills that most of us learn through observation and imitation of others' behavior. Our study could help explain what approaches to learning work best for children with autism, which would help to guide therapy."