NEUROANATOMICAL CORRELATES OF AUTISM SPECTRUM DISORDER AND THEIR CORRELATION WITH CLINICAL FEATURES A MULTICENTRIC MRI STUDY.

Background: Autism Spectrum Disorder (ASD) represents an highly prevalent neurodevelopmental disorder, defined as a constellation of early-onset social communication deficits and repetitive sensory-motor behaviors, with a multifactorial and poorly understood ethiology .The aim of the present study was to investigate and describe the brain morphologic characteristics (surface area SA, cortical thickness CT and volume) in children and adolescents with ASD and control subjects, in order to determine neuroanatomical correlates that underline ASD. Methods: an observational multicenter study was conducted across five Italian centers. 256 patients with ASD and 165 control group subjects were recruited from participant centers. Both autistic patients and controls underwent an MRI session. Clinical assessment was evaluated by a comprehensive battery of psychometric tools (Autism Diagnostic Observation Schedule, ADOS; Child Behavior Checklist, CBCL). Descriptive and inferential statistical techniques were applied, specifically, General Linear Model (GLM) analyses, using in-house Matlab scripts, were performed to compare regional morphological measures between ASD group and controls. Results: Four hundred and twenty-one subjects, of which 256 patients with ASD (196 males, 6,64 ± 3,80 years) and 165 controls (107 males, 6,54 ± 3,18 years), were recruited. ASD patients showed significantly increased area in the left medial orbitofrontal cortex than control group, whereas no significant cortical volume (CV) differences between ASD patients and controls were observed. ASD patients were characterized by significantly increased cortical thickness in the left superior temporal cortex. A secondary analysis set on subsamples of patients with available behavioral information highlighted the following findings: a negative correlation between CT in the right insula and CBCL total and CBCL internalizing problem score, a positive correlation between SA in the left posterior cingulate cortex (PCC) and CBCL M 6 (conduct problems) scores. Concerning the correlation analysis focused on ADOS, a negative correlation between SA in the left medial OFC and ADOS “Repetitive behaviors” score has been described, as well as a negative correlation between CT in the right precentral gyrus (PCG) and ADOS-2 “Social Affect” score, CV in the left PCG and the “Total Score” and CV in the right superior frontal cortex (SFC) and the “Comparison Score”. Finally, positive correlations between SA and CV in the right pericalcarine cortex and ADOS “Restricted and Repetitive Behaviors” scores were found. Conclusion: Study results showed that potential clinical-neuroanatomical correlations of the ASD disease with the most common clinical scales used in daily practice such as CBCL and ADOS. The use of neuroimaging techniques could play a key role in clarifying the impact of structural and functional changes on the pathogenesis of ASD. To understand the possible relationship between neuroanatomical parameters and the scales items it is important since it could facilitate the diagnostic process and therefore promote targeted intervention strategies.