"We are most excited about the frequent lack of differences shown between autistic and non-autistic participants in our study," Dr. Gavin Buckingham of the University of Exeter, in the U.K., told Reuters Health by email. "If predictive control was broadly impaired in autism, as suggested by the extant literature, then we would expect to see clear autism-related differences across multiple eye-tracking and motor control variables. But this didn't happen!"
Atypicalities in how predictions and sensory information are processed in the brain are characteristic features of autism spectrum disorder (ASD). Some research has shown that prediction-dependent features are not always impaired in autistic individuals, suggesting that predictive processing atypicalities might be driven by task- or context-specific mechanisms.
Dr. Buckingham and colleagues assessed prediction-related measures of cognition, perception, gaze and motor functioning in 92 neurotypical individuals and compared the measures with those of 29 individuals with a clinical diagnosis of ASD.
Perception and action were strongly driven by prior expectations in both groups, and the predictive models were employed comparably at a sensorimotor level in both autistic and neurotypical individuals with varying levels of autistic-like traits, the researchers report in Brain.
Individuals with ASD appeared to display reduced uncertainty-related increases in gaze search rate, suggesting that there is a reduced distinction between stable and uncertain environmental conditions in ASD.
Contrary to previous studies, the authors found no chronic autism-related attenuations in the use of prior information; rather, autistic participants appeared to make typical predictions and then use those computations to control their actions.
"Overall, our results suggest that the mechanisms underpinning sensorimotor differences in autism are complex and context-sensitive," Dr. Buckingham said. "So, while autistic people may excel at a motor skill under some task environments, they may struggle performing the same skill under a different set of conditions."
"This is promising from an applied perspective, as environmental conditions can often be adjusted by practitioners to suit individual needs," he said. "We hope that future research will begin to shed light on how task conditions can be optimized in this way to reduce sensorimotor difficulties in autism."
"Our research team has already started examining the implications of these results using Immersive Virtual Reality, which allows us to precisely control and manipulate the user's environment," Dr. Buckingham said. "By adding this technology to our existing eye-tracking and motion capture analysis, it is hoped that we can better understand the specific mechanisms that underpin sensorimotor difficulties in autism. This further investigation will facilitate the development of specific learning tools and coaching techniques for practitioners within the autism community."
Dr. Cristina Becchio of the University of Turin, Italy, who has researched prospective sensory control in children with autism, told Reuters Health by email, "Context-independent sensorimotor predictions are not attenuated in ASD. The problem is volatility (uncertainty), not prediction."
"The study was not designed to examine volatility, and the finding of differences in gaze patterns must be interpreted with caution," she said. "Future studies are needed to experimentally manipulate and statistically compute the effect of uncertainty on sensorimotor integration."
"These findings may have significant clinical implications, as various motor interventions rest on expectation-driven action and sampling behaviors," said Dr. Becchio, who was not involved in the new work. "These findings may be important for a better understanding of existing therapies and for designing new interventions."
By Will Boggs MD
SOURCE: https://bit.ly/3naaE72 Brain, online September 24, 2020.
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