Synchronized Sound and Motion Offer New Insight Into Autism

Toddlers with autism spectrum disorders (ASDs) are frequently preoccupied with synchronized sound and motion, such as the precise matching of audiovisual presentation that occurs during the act of speaking. Children with ASDs tend to focus on a person’s mouth when they are speaking, whereas children unaffected by ASDs focus on socially meaningful movements of the human body, such as gestures and facial expressions.

Autism spectrum disorders (ASDs) affect social interaction and communication, which can cause delays or difficulties in developing fundamental skills from infancy to adulthood. Autism is the most common form of ASD with an estimated three to six children out of each group of 1,000 being diagnosed with the condition. In addition, males have a four times greater likelihood of being autistic than females. Unusual, repetitive, or severely limited activities and interests, in addition to having impaired social interaction and difficulties with verbal and nonverbal communication, characterize autism. Other ASDs include Asperger syndrome, Rett syndrome, childhood disintegrative disorder, and pervasive developmental disorder not otherwise specified.

According to Ami Klin, Ph.D., and colleagues at Yale University School of Medicine, the surprising discovery that children with ASDs are attracted to the synchronization of sound and motion may lead to earlier diagnosis of autism as well as a better understanding of the origin and development of the condition. The report can be found in the online journal Nature.

In a statement, Dr. Klin said, “Typically developing children pay special attention to human movement from very early in life, within days of being born.” However, children with autism don’t follow human movement, which causes them to miss social information that is communicated through motion, which is “likely to adversely affect the course of their development.”

The Yale team studied reactions of a group of toddlers that included 21 who had ASDs, 16 who were developmentally delayed but non-autistic, and 39 who were typically developing children. Using a technique known as motion capture, in which a video figure wears lights on parts of its body that capture the path of the figure’s movement, the researchers observed the children’s focus of attention on light patterns in conjunction to the figure’s voice. The image was played normally on one side of the screen while it was played upside-down and in reverse on the opposite side of the screen. A total of four light patterns were played to the children. The results showed that those with autism spent approximately 50 percent of their time watching both the upright figure and the inverted one while the other two groups of children spent about 60 percent of their time watching the upright figure.

When a fifth pattern was played, depicting the figure playing the common childhood game of pat-a-cake that included the sound of a clap as the hands of the figure came together, the autistic children showed a significant preference for it by watching it almost 66 percent of the time. The synchronous sound and motion only occurred on the upright side of the screen since the motion was both backward and upside-down on the opposite side. The reaction to this new pattern by the two control groups was unchanged at around 60 percent.

In a second analysis, the researchers introduced two new patterns to 10 children with autism that confirmed their theory that toddlers with autism would prefer the patterns having synchronous motion and sound. Regarding the results of the studies, co-author Warren Jones, Ph.D. stated, “Audio-visual synchronies accounted for about 90 percent of the preferred viewing patterns of toddlers with ASD and none of unaffected toddlers.” He then added, “Typically-developing children focused instead on the most socially relevant information.”

The researchers concluded that the results developmentally “mark an important, early point along an alternative path of neural and behavioral specialization.” The finding could lead to educational practices that may help young autistic children to build social referencing skills.