Using Motion Capture Technology to Characterize Motor Atypicalities in Infants at Risk for Autism Spectrum Disorder
Atypical motor behaviors have been reported in infant siblings of children with autism spectrum disorder (ASD) (Leonard et al., 2014). However, studies reporting motor impairments in this population often rely on retrospective data or performance on unspecific standardized tests. In this study, we investigated movements in infants at risk for ASD using motion capture technology, which provides an objective measure of kinematic profiles with high spatiotemporal resolution.
The aim of the study was to investigate kinematic variables linked to motor planning and execution in infants at risk for ASD during an interceptive action task (catching a moving object).
Our sample consisted of 58 ten-month-old infant siblings at high familial risk for ASD (HR group, n = 39) and low risk infants without familial history of ASD (LR group, n = 19), participating in an ongoing longitudinal study. Using a design by Ekberg et al. (2016), we assessed the ability to catch a ball, which was rolling towards the infant on a curvilinear path. Movements of the infant and the object were recorded with an eight-camera 3D motion-capture system (Qualisys) using passive reflexive markers. Statistical analysis was performed using linear mixed models.
The groups did not differ in terms of successful catches. However, using velocity profile analysis and dividing a movement into movement units (acceleration followed by deceleration), we found a group difference implicating atypical planning. The HR group initiated the reach (onset of transport unit, i.e. the movement’s largest subunit) later (M = 284.91 mm (distance to object), SE = 5.50) than the LR group (M = 296.16 mm, SE = 5.53), F(1, 375) = 4.18, p = .42. Regarding motor execution, peak velocity of the transport unit was significantly lower in the HR group (M = 1.77 mm/sample, SE = 0.08) than in the LR group (M = 1.94 mm/sample, SE = 0.08), F(1, 392) = 5.19, p = .023. Congruently, the distance traveled during the transport unit was significantly lower in the HR group (M = 177.89 mm, SE = 7.13) than in the LR group (M = 196.85 mm, SE = 7.15), F(1, 392) = 7.06, p = .008.
Using detailed motion capture technology, this study was the first to investigate motor function in early development in infants at risk for ASD. Our findings reveal a complex pattern of both later initiation and differences in motor execution, but also intact ability to catch a moving object. The observed movement patterns highlight the importance of fine-grained measures of motor control in addition to more general measures from standardized scales.