OC14.04: Cortical brain morphometry in adults born small for gestational age and its association with ADHD disorder

The association between SGA and ADHD has been described, but the mechanisms and specific neuroanatomical modifications remain poorly documented. Here, we explore adult brain imaging and functional evaluation in patients born SGA. A cohort study in adults born between 1975-1995 (mean age 33.9 y; N = 98, 53 SGA defined as birthweight<10th centile and 45 controls). MRI T1 scans and Adult ADHD Self-Report Scale (ASRS) questionnaires were collected. Freesurfer software was used for cortical and subcortical data processing. Cluster- and voxel-wise analysis were used to assess cortical and subcortical brain morphometry. ADHD using the ASRS was based on a dichotomous method. Association between ASRS and neuroanatomical regions was explored using a Welsh t-test. SGA had a 6% reduction in estimated intracerebral volume. Cortical morphometric changes included symmetrical decreases in surface area in prefrontal and posterior cingulate regions, as well as reduction volume in insulates, prefrontals, postcentrals, lateraloccipitals, and left unilateral fusiform regions. Subcortical structures also showed significant voxel-wise differences: WM cerebellum, thalamus, basal ganglia, posterior corpus callosum. ADHD rates showed no significant differences between SGA and controls (8% vs 7.32%, p-value = 0.9). However, elevated ASRS scores in SGA were linked to a smaller left superior frontal area (Adjusted mean difference [AMD], Δ, 0.113 mm2, 95%CI 0.03-0.2) and reduced bilateral latero-occipital volume (AMD Right Lateraloccipital, Δ, 0.48 mm2, 95%CI 0.26-0.71; AMD Left Lateraloccipital, Δ, 0.28 mm2, 95%CI 0.16-0.4). This study shows long-lasting cortical morphometric changes in adults born SGA. Global volume reduction and regional alterations in surface area and volume might partially explain the reported association between SGA and ADHD.