Shorter spontaneous fixation durations in infants with later emerging autism

Abstract

Little is known about how spontaneous attentional deployment differs on a millisecond-level scale in the early development of autism spectrum disorders (ASD). We measured fine-grained eye movement patterns in 6-to 9-month-old infants at high or low familial risk (HR/LR) of ASD while they viewed static images. We observed shorter fixation durations (i.e. the time interval between saccades) in HR than LR infants. Preliminary analyses indicate that these results were replicated in a second cohort of infants. Fixation durations were shortest in those infants who went on to receive an ASD diagnosis at 36 months. While these findings demonstrate early-developing atypicality in fine-grained measures of attentional deployment early in the etiology of ASD, the specificity of these effects to ASD remains to be determined.

Figure 1

(a) Median fixation duration data by outcome group (HR-ASD N = 15, HR-no ASD N = 30, LR N = 49). Calculations are weighted as described in the text. Stars show the significance of the analyses reported in the text. Error bars show Standard Error of the Means. (b) Scatterplot showing the relationship observed across all infants between fixation duration during infancy and ADOS scores at 36 months. The linear regression line shows the significant relationship described in the text.