Abstract
BACKGROUND: Neurofibromatosis Type 1 is a genetic condition diagnosed in infancy that substantially increases the likelihood of a child experiencing cognitive and developmental difficulties, including Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD). Children with NF1 show clear differences in attention, but whether these differences emerge in early development and how they relate to broader difficulties with cognitive and learning skills is unclear. To address this question requires longitudinal prospective studies from infancy, where the relation between domains of visual attention (including exogenous and endogenous shifting) and cognitive development can be mapped over time. METHODS: We report data from 28 infants with NF1 tested longitudinally at 5, 10 and 14 months compared to cohorts of 29 typical likelihood infants (with no history of NF1 or ASD and/or ADHD), and 123 infants with a family history of ASD and/or ADHD. We used an eyetracking battery to measure both exogenous and endogenous control of visual attention. RESULTS: Infants with NF1 demonstrated intact social orienting, but slower development of endogenous visual foraging. This slower development presented as prolonged engagement with a salient stimulus in a static display relative to typically developing infants. In terms of exogenous attention shifting, NF1 infants showed faster saccadic reaction times than typical likelihood infants. However, the NF1 group demonstrated a slower developmental improvement from 5 to 14 months of age. Individual differences in foraging and saccade times were concurrently related to visual reception abilities within the full infant cohort (NF1, typical likelihood and those with a family history of ASD/ADHD). CONCLUSIONS: Our results provide preliminary evidence that alterations in saccadic reaction time and visual foraging may contribute to learning difficulties in infants with NF1.