In 2012 Flanagan and colleagues presented evidence that infants’ head lag during a pull-to-sit task at age six months was significantly associated with a diagnosis of autism spectrum disorder at 36 months. The authors acknowledged limitations of the study, including a relatively small sample and the absence of a comparison group of infants with idiopathic developmental delays, and many clinicians were skeptical as to whether a marker for delayed motor development could serve as a useful early indicator of autism spectrum disorder (ASD).

However, it appears that Flanagan and colleagues may have been early proponents of an important development in the literature on the early identification of autism. A new paper offers additional support for the notion that the earliest indicators of autism in infants may be neither social nor language abnormalities, but motor delays.

In a paper recently published on-line by the journal, Child Development, Kelsey West at the University of Pittsburgh presents the results of a meta-analysis examining the relationship of infant motor development and autism spectrum disorder (West, 2018). West’s search of the literature yielded reports of 26 studies that included both a cohort of infants with a confirmed ASD diagnosis and a cohort of age-matched typically developing infants, and that utilized measures of motor ability. The studies collectively presented individual data from 1,953 infants with ASD and 78,473 neurotypical infants. Robust statistically significant group differences indicated that motor ability is less advanced in infants with ASD than in neurotypical peers, a differences which persisted “across all levels of all moderator variables” and led the author to suggest that such “consistency speaks to the pervasiveness of motor disruption.” (p. 12)

In a related study reported in the same paper, West examined the relationship between motor and communicative ability in infants with ASD. Nine studies, including 890 infants with ASD, yielded 13 relevant effect sizes; results indicated a significant relation between motor ability and communication in infants with ASD. West concluded that “communicative development in ASD could be better understood by considering the role of infants’ developing bodies and repertoires for action.” (p. 13)

A second paper, published on-line by the Journal of Autism and Developmental Disorders examined whether “variability in growth of verbal language (i.e., expressive and receptive) and non-verbal communication (i.e., gestures)” in infants was related to “to later functioning and ASD symptomatology.” (Franchini et al., 2018) The sample included 482 High Risk infant siblings of children with ASD, and 178 control infants. These authors were primarily interested in the mapping the trajectories of language development and much of the paper is devoted to that topic. However, the authors also reported that in these High Risk infants, 28% of whom were subsequently diagnosed with ASD, “gross motor skills . . . were positively associated with verbal reception development” and “both fine and gross motor skills were positively related to gesture development.” (p. 10) The authors concluded that motor skills could “affect the development of language and gesture acquisitions” and that “Early intervention plans should hence consider motor skills as a potential contributor to the development of communication abilities.” (p. 11) Finally, they observe that “motor skills may represent an essential target, beyond more obvious language related abilities, in early intervention plans for children at risk.”

Neither of these papers constitutes definitive evidence that very early motor delays can be seen as a reliable screening indicator for autism spectrum disorder. However, they may serve to call the attention of the field to the importance of including differences in motor development in a theoretical formulation of how autism emerges.

References

Flanagan, J. E., Landa, R., Bhat, A., & Bauman, M. (2012). Head Lag in Infants at Risk for Autism: A Preliminary Study. American Journal of Occupational Therapy, 66(5), 577–585. https://doi.org/10.5014/ajot.2012.004192

Franchini, M., Duku, E., Armstrong, V., Brian, J., Bryson, S. E., Garon, N., … Smith, I. M. (2018). Variability in Verbal and Nonverbal Communication in Infants at Risk for Autism Spectrum Disorder: Predictors and Outcomes. Journal of Autism and Developmental Disorders. https://doi.org/10.1007/s10803-018-3607-9

West, K. L. (2018). Infant Motor Development in Autism Spectrum Disorder: A Synthesis and Meta-analysis. Child Development. https://doi.org/10.1111/cdev.13086