Longitudinal Examination of Head Control in Infants at High- and Low-Risk for Autism Spectrum Disorder from Two to Six Months

Background: Toddlers with autism spectrum disorder (ASD) show atypical motor and cognitive development in the first two years of life (Landa et al., 2013). Recently, motor delays have been documented in infants at high-risk for ASD as young as 6-months of age, specifically highlighting head control as an area of concern (Bhat et al., 2012, Flanagan et al., 2012). Prospective, longitudinal measurement of motor milestones, beginning as early as 2-months, will inform early detection methods and support the development of novel interventions for ASD.

Objectives: The goal of this study is to explore differences in the emergence of head control abilities, coordinated with visual and auditory attention, in 2- to 6-month-old infants at high- and low-risk for ASD.

Methods: The Bayley Scales of Infant and Toddler Development was administered monthly to infants enrolled in a large, longitudinal, federally funded study at high-risk (HR, N=23) and low-risk (LR, N=15) for ASD at five time points between 2- and 6-months of age. Four items specifically measuring head control were selected from the Bayley and included in the current analysis: follows-ring, turns-to-sound, shifts-attention, and follows-ball. Each item was administered with the infant sitting in the caregiver’s lap and required head control in conjunction with visual and/or auditory attention. Chi-square analyses were used to identify differences in reaching each of these milestones at monthly time points from 2- to 6-months of age. Data collection for this study is ongoing and we anticipate an additional 25 participants to be added to the current sample before May, 2017.

Results: Overall, HR infants appeared to meet each milestone later than LR infants. Milestones were considered to be met when 100% of infants within a group demonstrated the behavior. LR infants met the follows-ring milestone at 3-months while HR infants met this milestone at 5-months. There was a marginally significant between-group difference at 3-months (p=0.07). The turns-to-sound milestone was achieved at 4-months for LR infants and 5-months for HR infants. No significant differences were observed at a single time point for this item. The shifts-attention milestone was achieved at 4-months for LR infants and 5-months for HR infants, with no observed significant differences between groups at any time point. Finally, results revealed that LR infants met the follows-ball milestone at 4-months, while HR infants met this milestone at 5-months. A marginally significant between-group difference for this item was observed at 2-months (p=0.1) and a significant difference was observed at 4-months (p=0.01).

Conclusions: This preliminary study is one of the first to provide evidence for very early delays (starting at 2-months) in HR infants’ use of head control while attending to visual and auditory stimuli. Identification of early differences in head control, especially when paired with measures of attention, can contribute to our understanding of motor ability within the cascade of developmental and social abnormalities observed in children with ASD. These results could have significant implications for early detection of ASD and the development of early intervention.