Eye Movement Control as a Functional Biomarker of Brain Development in the Child Welfare Population
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Background: Prenatal Alcohol Exposure (PAE) can result in a continuum of neurological, behavioural, physical and learning deficits collectively referred to as fetal alcohol spectrum disorder (FASD). Eye movement tasks have been shown to be a promising approach to assessing brain dysfunction in children with FASD. However, these studies were limited to school-aged children because of the nature of the structured tasks. Our objectives were to investigate whether (i) a set of standardized screening tools (Ages and Stages Questionnaires (ASQ)) were able to identify specific patterns of developmental delay in young children who have a history of PAE, and (ii) the pattern of eye movement behaviours obtained from watching video clips could be used to differentiate young children 10-78 months with a history of PAE from control participants. Methods: Sixteen children with a history of PAE and twenty-one control participants watched 6-16 minutes of video clips comprised of 2-4 second clipets that were semantically unrelated. Eye movements were recorded using the Eyelink 1000. Results: The overall gaze distributions of children with a history of PAE did not differ from controls. Data were analyzed for both developmental and group effects. The average amplitude of saccades increased with age in the control, but not the PAE, group. Both groups exhibited developmental effects of age on fixation duration and the number of saccades per movie. Group differences were also observed; children with a history of PAE exhibited smaller amplitude saccades. Further analysis revealed that in typically developing children, the frequency of smaller amplitude saccades decreased with age. This developmental change was absent in children with PAE. Results from the ASQ indicate that children who scored poorly across one domain tended to score poorly across multiple domains. Conclusions: The results of this study extend previous findings that eye tracking has the potential to quantify brain damage associated with PAE. Future studies should continue to explore free viewing as a means to identify children with PAE who would benefit from further diagnostic assessment.