Minute Movements a Biomarker for Autism Severity?

Megan Brooks

December 08, 2014

WASHINGTON ― Movement patterns that are imperceptible to the human eye but that are present in children with autism spectrum disorder (ASD) and their parents may provide a clue to the disorder's severity, new research suggest.

"We found speed fluctuations at millisecond time scale that could serve as a quantitative biomarker for ASD," study investigator Di Wu, a PhD graduate student at Indiana University Bloomington, told Medscape Medical News.

The researchers have developed a quantitative way to assess these otherwise ignored variations in movement.

These movements "not only separate subjects with ASD from typical adults but also provide a separation within ASD groups that agree with their abilities to speak," Wu said.

"This is important because it may enable us in the near future to better understand impairments in acquiring spoken language in ASD. Many individuals in the spectrum cannot talk but can comprehend us and have cognitive abilities that we cannot appreciate due to the lack of spoken language," co–principal investigator Elizabeth Torres, PhD, of Rutgers University, New Brunswick, New Jersey, told Medscape Medical News.

The similarity in movement patterns between children with ASD and some of their parents supports a potential genetic link in ASD, Wu noted.

The study was presented here at the Society for Neuroscience 2014 Annual Meeting.

Motor Deficits

Individuals with ASD are known to have problems with motor skills. In earlier studies, the researchers observed that people with autism have more random and disorganized movements than do healthy individuals. This latest study builds on this idea and suggests that micromovement patterns may have a genetic component.

They used motion sensors to record the hand speed of 30 children and adults with autism, eight healthy adults, and 21 parents of children with autism as they extended and retracted their hand to touch a specific spot on a touch screen. They each did this about 100 times in a row, and the sensors recorded 240 movements per second. They measured the continuity of the speed of pointing behaviors.

"In healthy adults, the minute fluctuations in the speed of their movements, which we call peripheral spikes, or p-spikes, normally occur at the onset or at the end of the arm extension exercise," Wu explains in a news release. "They show very few p-spikes during the actual action, as the hand speeds up or slows down en route to the target. However, healthy children in the 3- to 5-year-old range have random patterns of p-spikes, as do adults and children with autism spectrum disorder."

This suggests that p-spikes normally become more organized with age in typically developing individuals. However, in children and adults with autism, the p-spikes remained random, the researchers observed.

Unexpected Findings

"ASD subjects do not mature like typically developing subjects but remain with the same lack of movement controls they had while being young children," said co–principal investigator Jorge José, PhD, of Indiana University Bloomington.

The study also suggests that p-spike patterns may be useful in determining severity of ASD.

"Normally, children get more coordinated as they age, but we found that the young children with autism and the adults with autism all produced random p-spikes, showing that they do not transition as they develop," Dr José said in the release.

"We also found a correlation between the randomness of the p-spikes and the severity of the autism disorder. Among those with autism, the more random their p-spikes, the lower spoken language ability they had overall," Dr José said.

Unexpectedly, some of the parents of the children with autism had random p-spikes clustering in the graph in a manner similar to that of their children. "This finding suggests that genetics may play a role in p-spike patterns," Wu said. "We will need to further explore this result in other populations with neurodevelopmental disorders of known genetic origins and their families to better understand the surprising findings."

The study was funded in part by the National Science Foundation. The authors have disclosed no relevant financial relationships.

Society for Neuroscience 2014 Annual Meeting: Poster 140.21. Presented November 16, 2014.

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