July 2011

Early research characterizes gait associated with autism

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Results could have clinical implications

By Larry Hand

Little research has been published about gait patterns in children with autism, but that could be changing. One recently published study, although small, appears to lay the foundation for more focused research and could have clinical implications as well.

In the February issue of Clinical Biomechanics, researchers at the University of New Brunswick in Fredericton, New Brunswick, Canada, published what they describe as the first comprehensive analysis of 3-D joint and muscle gait patterns in children with autism. The study found that a group of autistic children, compared to controls, had a significantly higher cadence, increased upper flexion of the ankle in swing phase, decreased peak ankle joint angles, and significantly smaller peak plantar reflex moments.

The study included 12 children with autism, ages 5 to 9, plus 22 age-matched control participants. However, the researchers excluded toe-walkers and children with Asperger syndrome or pervasive developmental disorder not otherwise specified (who typically would fall under the definition of full autism spectrum disorder [ASD]). Many children with ASD have sensory sensitivities that make them behave less than ideally when researchers use markers, tape, and Velcro to capture patterns for wave form analysis, explained senior author Victoria Chester, PhD, associate professor of kinesiology at UNB’s Andrew and Marjorie McCain Human Performance Laboratory.

“We were successful in getting them through,” she added, probably because of the exclusion of some children from the study.

The researchers used an eight-camera motion capture system to track 3-D trajectories of reflective markers placed on the children’s skin. They used custom software to compute cadence, velocity, and percent cycle spent in single limb stance for every gait cycle. They used parameterization techniques and principal component analysis to analyze their data and then compared the two sets.

“We actually managed to get kinematic and kinetic data sets for a group of kids with autism,” Chester said. “And you really need both sets of data to get a better understanding of what their gait patterns are like. I was surprised that the children could actually be grouped this way for a study. They often appear to the naked eye to be very different from one another.”

So what do the study results mean to practitioners?

“Given our small sample size, we remain fairly conservative in terms of our clinical relevance,” Chester said. “However, the findings may be important in terms of treatment planning for children with autism [plantar flexor strength training, stretching, and orthotics]. Gait analysis can provide clarification in terms of identifying gait deviations and treatment planning. The effects of treatment on gait can also be monitored. Practitioners should know that children with autism may benefit from the objective data made available from gait analyses for treatment planning. We still need to learn more about the autism spectrum and associated gait disorders, and this paper is a start in that direction.”

Whether gait pattern analysis could be used to screen for possible autism disorders is a “huge topic, very controversial,” Chester said. And while some people are looking into that possibility, it was not a focus of the UNB research, she said.

Dawn-Marie Ickes, PT, a physical therapist at Core Conditioning PT in Studio City and Burbank, CA, agreed that gait analysis screening is not close to being ready for prime time.

“I wouldn’t say it is something that is a clinically objectifiable screening program for autism. Symptoms do overlap, but not all children with sensory integration dysfunction have autism. However, it could be a predictor of other things that look like autism but aren’t,” Ickes said. “The best takeaway from this study for practitioners is that these abnormalities can pose value for predicting ASD if they’re coupled with sensory integration screening.”

Although other symptoms and aspects often are given priority when managing autism, Chester encouraged practitioners to remember that there is a physical component to autism as well, making it necessary to treat the whole child.

“A child who can’t keep up with others on the playground from a motor perspective is also affected socially,” she said.

Larger studies are now needed that include children from all autistic-related groups, Chester said, to facilitate an understanding of how gait differs across the autism spectrum.

Larry Hand is a writer based in Massa­chusetts.

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