What is it about?

What’s known? • Autistic children have been found to exhibit differences in their frequency of head movement while watching dynamic stimuli compared to neurotypical children. • A smaller study suggested that computer vision analysis can help in accurately and automatically estimating these head movement patterns. What’s new? • Based on a larger sample, this study confirmed that computer vision analysis can be used to objectively and automatically extract measures of head movement dynamics exhibited by autistic and neurotypical toddlers recorded via a digital app during a well-child checkup in primary care. • We found that the rate, acceleration and complexity of the head movements are significantly higher in autistic toddlers compared to neurotypical toddlers. What’s relevant? • Combining head movement features with other digital behavioral biomarkers can open avenues to develop a multimodal computer vision and machine learning based digital phenotyping tool, capable of offering a quantitative and objective characterization of early behavioral features of autism.

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Why is it important?

Background: Early differences in sensorimotor functioning have been documented in young autistic children and infants who are later diagnosed with autism. Previous research has demonstrated that autistic toddlers exhibit more frequent head movement when viewing dynamic audiovisual stimuli, compared to neurotypical toddlers. To further explore this behavioral characteristic, in this study, computer vision (CV) analysis was used to measure several aspects of head movement dynamics of autistic and neurotypical toddlers while they watched a set of brief movies with social and nonsocial content presented on a tablet. Methods: Data were collected from 457 toddlers, 17-36 months old, during their well-child visit to four pediatric primary care clinics. Forty-one toddlers were subsequently diagnosed with autism. An application (app) displayed several brief movies on a tablet, and the toddlers watched these movies while sitting on their caregiver’s lap. The front-facing camera in the tablet recorded the toddlers’ behavioral responses. CV was used to measure the participants’ head movement rate, movement acceleration and complexity using multiscale entropy. Results: Autistic toddlers exhibited significantly higher rate, acceleration and complexity in their head movements while watching the movies compared to neurotypical toddlers, regardless of the type of movie content (social versus nonsocial). The combined features of head movement acceleration and complexity reliably distinguished the autistic and neurotypical toddlers. Conclusions: Autistic toddlers exhibit differences in their head movement dynamics when viewing audiovisual stimuli. Higher complexity of their head movements suggests that their movements were less predictable and less stable compared to neurotypical toddlers. CV offers a scalable means of detecting subtle differences in head movement dynamics, which may be helpful in identifying early behaviors associated with autism and providing insight into the nature of sensorimotor differences associated with autism.


The findings suggest that the rate and acceleration of the head movements are higher for the autistic individuals. In addition, the time-series analysis via multiscale entropy suggests that these individuals have higher complexity in head movements. Thus, both the higher acceleration and complexity in autistic toddlers indicates this was caused due to instability and their difficulty in holding a static posture that are in contrast with other studies suggesting it was repetitive head movements. Also, such a unstable head movements can be related to sensory motor integration differences in autistic toddlers.

Pradeep Raj Krishnappa Babu
Duke University

Read the Original

This page is a summary of: Complexity analysis of head movements in autistic toddlers, Journal of Child Psychology and Psychiatry, August 2022, Wiley,
DOI: 10.1111/jcpp.13681.
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