Alterations in microarchitecture and network integrity in diffusion tensor images of children with marginal intelligence or intellectual disabilities.

Purpose: To investigate damage to fiber bundles and brain networks in children with marginal intelligence (MI) or intellectual disability (ID) by using Diffusion Tensor Imaging (DTI) sequences.

Methods: Thirty healthy children, 25 with MI, 35 with ID, and 32 with both ID and attention deficit hyperactivity disorder (ADHD) underwent 3.0 T MRI scans, including DTI sequences. Analysis of the DTI data yielded correlation tractography, network measures, and graph visualizations.

Results: Children with MI, ID or both ID and ADHD have damage in the bilateral arcuate fasciculi, bilateral superior longitudinal fasciculi and thalamic radiations, corpus callosum's body, and right corticostriatal tracts. Furthermore, both the MI and ID-ADHD groups were affected in the right parietal aslant tract, bilateral corticospinal tracts, and bilateral medial lemnisci, which were not affected in patients with ID alone. The MI, ID and ID-ADHD groups exhibited a significantly lower density, global efficiency, and rich club coefficient than the controls. Patients with MI, ID, or both ID and ADHD had no nodes in the bilateral middle and inferior frontal gyri. Moreover, individuals with ID, alone or combined with ADHD, also lacked nodes in the bilateral temporal lobes.

Conclusion: Children with MI, ID, or comorbid ID and ADHD exhibited significant morphological abnormalities in fiber tracts, substantial reductions in fiber bundle volumes, and disrupted neural network connectivity. Furthermore, graph visualizations of the connectome reveal a progressive increase in the defect of hub nodes, worsening from MI to ID, whether alone or in conjunction with ADHD, when compared to normal controls.