Abstract
Abstract: :
Purpose: We previously reported preschool visual, visuomotor and spatial deficits and delays, related to parietal and frontal lobe function in children born prematurely (ARVO 2002) and similar but lesser deficits in a subgroup of children, identified in the Cambridge Infant Screening Programmes, with significant hyperopia and poor accommodation (Atkinson et al, Strabismus, 10, 187, 2002). Here we measure attentional deficits and compare form with motion coherence thresholds in these cohorts at age 6 years, using new tests selective for visual cortical 'dorsal ' and 'ventral' streams and compare outcome to early abnormalities (including those found on neonatal structural MRI). Methods: The two cohorts were (a) H–group: 76 children with significant infant hyperopia (+4D or more in at least one axis at 11 months), matched to 95 emmetropic controls; (b) P–group: 43 premature infants (gestational age < 30 weeks, <1500gm), both tested at 6–7 years. We measured (a) 4 subtests of TEACh (Test of Everyday Attention in Children, and new adaptations for younger children) covering selective visual search, sustained attention, inhibitory frontal function; (b) form and motion coherence thresholds (Gunn et al, NeuroReport, 13, 843, 2002). Children wore spectacles for testing to fully correct any refractive errors. Results: Both cohorts showed lower mean scores compared to controls on attention tests, the P–group being significantly different on all 4 measures, while the H–group showed poorer selective search and frontal inhibition but were not significantly different on auditory sustained attention. H–group showed normal form and motion coherence thresholds, while the P–group showed higher thresholds, with a subset having elevated motion thresholds compared to form (dorsal vulnerability). Conclusions: An association between specific perinatal abnormalities seen on structural MRI and dorsal stream deficits, identified by raised motion coherence thresholds and attention deficits, has been found in children born prematurely. The use of accommodative and refractive measures in infant screening of normally developing children to predict risk of attentional disorders (ADHD) at school will be considered.
Keywords: visual development: infancy and childhood • hyperopia