Study Of Brain Morphometry Characteristics And Their Association With ADOS Scores Of Social Behavior Subtypes In Early Ages Of Autism Spectrum Disorder

Autism spectrum disorder(ASD)is a neurodevelopmental disorder characterized by impaired social communication as well as restrictive and repetitive behaviors.In recent years,a large number of studies have reported certain brain morphological changes,such as brain volume,density,cortical thickness,cortical surface area,local gyrification index,in ASD compared to typically developing(TD)individuals based on structural magnetic resonance imaging.It has been reported that the ASD symptoms usually appear in early childhood and continue into adulthood,and the morphological changes of ASD subjects vary across different ages.In particular,the age of 4-5 years old is the pivotal stage for the development of key functional brain circuits and networks,and the most obvious stage of exhibiting ASD symptoms as well.It is therefore beneficial to unveil the brain charateristics affected by ASD at an early stage by means of studying the brain morphological characteristics of young ASD children(especially 4-5 years old).However,to date there are few studies on the latter aspect.In addition,since ASD is a spectrum disorder with complicated etiology and variable behaviors,it is challenging to accurately distinguish among different subtypes of ASD,and to further characterize potential morphological differences as well as their relationship with ASD symptoms among different subtypes.In order to address the above mentioned two challenges,the present study investigated the brain morphological characteristics of different social subtypes of ASD at the age of 4-5 years old,and further analyzed the correlation between morphological characteristics and symptom severity scores measured using the Autism Diagnostic Observation Schedule(ADOS).We adopted the T1-weighted structural magnetic resonance imaging(MRI)brain data collected by our collaborator Associate Professor Rong Zhang from School of Medicine,Peking University.There were 128 subjects including 98 4-5 years old ASD and age-matched 30 TD children.The 98 ASD children were further categorized into three social subtypes(27 Aloof,46 Passive,25 Active-but-Odd(AbO))determined by the scores of Beijing Autism Subtyping Questionnaire(BASQ).By combining both the voxel-based morphometry(VBM)and surface-based morphometry(SBM)methods which focus on the brain volume and cortical surface characteristics respectively,we systematically analyzed the potential changes in gray matter,white matter,and cortical gyrificiation measurements(cortical thickness,cortical surface area,cortical volume,and cortical gyrification)between ASD and TD groups,as well as their correlation with ADOS scores in the three different ASD social subtypes.Results showed that the gray matter volume of certain brain regions(including temporal lobe,superior and middle frontal lobe,right superior and middle orbital frontal lobe,left superior parietal gyrus,right posterior central gyrus,left middle temporal gyrus,right middle frontal gyrus,left middle temporal pole)significantly increased in ASD compared with TD at 4-5 years old,while no differences in other measurements or among the three social subtypes were found.Moreover,there was a different correlation relationship between the increased gray matter volume in these brain regions in ASD and the ADOS scores(both sub-scale and total score)among the three social subtypes.This study identified potential brain imaging markers from a brain morphological perspective in order to distinguish ASD children and their social subtypes from TD children thereby providing novel insights for the early diagnosis and intervention treatment of ASD.