Abstract

Background . Even though mild cognitive impairments are common in patients with attention deficit hyperactivity disorder (ADHD), there are no studies of morphometric brain parameters in children with ADHD and comorbid mild cognitive impairments. Objective. The aim of the study is to determine and perform comparative analysis of MR-morphometric brain parameters in children with ADHD depending on the presence or absence of comorbid mild cognitive impairments. Methods. Participants are children aged from 7 to 8 years with ADHD without comorbid pathology (CP), ADHD with mild cognitive impairment (MCI), MCI without ADHD, and healthy children. All participants underwent brain magnetic resonance imaging followed by morphometry to obtain quantitative parameters of large brain structures, cerebral cortex gyri, basal ganglia, cerebellum, and lateral ventricles. Results . 90 children were examined. ADHD with MCI group has shown significant decrease in the volumes of caudate nuclei bilaterally and hippocampus on the right, as well as decrease in the volumes of right superior parietal gyrus, supramarginal gyrus, and frontal cortex. ADHD without CP group has shown different changes: decrease in the volume of putamen on both sides and thalamus on the left, increase in the volume of six and decrease in the volume of the cortex of four gyri, cortex thinning of four gyri with cortex thickening of one gyrus, volume increase of four cerebellar lobules. MCI without ADHD group has shown bilateral enlargement of lateral ventricles, decrease in the volume of right pallidum and seven gyri cortex, mostly on the right side, as well as decrease in the volume of four cerebellar lobules. Direct comparison between the two ADHD groups has shown significant differences up to lower total cortex volume with 5 gyri of left hemisphere and 7 gyri of right hemisphere in the ADHD with MCI group. Participants of ADHD groups compared to healthy individuals and the MCI without ADHD group did not show any age-related dynamic decrease in the volumes of cerebral cortex. Conclusion. ADHD is characterized by parallel presence of two pathogenetic processes: cerebral cortex hypoplasia and delayed age-related changes in other areas. Significant differences in morphometric parameters were revealed between ADHD without CP and ADHD with MCI. It suggests individual treatment for such patients and revision of approaches to morphometric brain studies in patients with ADHD. Enlargement of lateral ventricles in MCI may indicate the effect of perinatal pathology on these conditions’ etiology.