Assessing cortical features in early stage ASD children

Abstract

Autism Spectrum Disorder (ASD) is defined as a neurodevelopmental disorder largely investigated in the neurologic field. Recently, neuroimaging studies have been conducted in order to investigate cerebral morphologic alterations in ASD patients, demonstrating an atypical brain development before the clinical manifestations of the disorder. Cortical Thickness (CT) and Local Gyrification Index (LGI) distribution for ASD children were investigated in this study, with the aim to evaluate possible relationship between brain measures and individual characteristics (i.e., IQ and verbal ability). 3D T1-w sequences from 129 ASD and 58 age-matched Healthy Controls (HC) were acquired and processed in order to assess CT and LGI for each subject. Intergroup differences between ASD and HC were investigated, including analyses of 2 ASD subgroups, split according to patient verbal ability and IQ. When compared to HC, ASD showed increased CT and LGI within several brain areas, both as an overall group and as verbal ability an IQ subgroups. Moreover, when comparing language characteristics of the ASD subjects, those patients with verbal ability exhibit significant CT and LGI increase was found within the occipital lobe of right hemisphere. No significant results occurred when comparing ASD patients according to their IQ value. These results support the hypothesis of abnormal brain maturation in ASD since early childhood with differences among clinical subgroups suggesting different anatomical substrates underlying an aberrant connectivity.

Keywords: MRI; autism; cortical thickness; local gyrification index; verbal ability.

Figure 1

Cluster-wise analysis mapped on the inflated common surface. Overall CT (left) and LGI (right) results, where each color is associated with different clusters; CT, cortical thickness; LGI, local gyrification.

Figure 2

Cluster-wise analysis mapped on the inflated common surface. CT (left) and LGI (right) results for VERB1-HC comparison, where each color is associated with different clusters; CT, cortical thickness; LGI, local gyrification; VERB1, verbal ability – health control.

Figure 3

Cluster-wise analysis mapped on the inflated common surface. CT (left) and LGI (right) results for VERB2-HC comparison, where each color is associated with different clusters; CT, cortical thickness; LGI, local gyrification; VERB2, no verbal ability; HC, health control.

Figure 4

Cluster-wise analysis mapped on the inflated common surface. CT (left) and LGI (right) results for IQ1-HC comparison, where each color is associated with different clusters; CT, cortical thickness; LGI, local gyrification; IQ1, intelligence quotient>70; HC, health control.

Figure 5

Cluster-wise analysis mapped on the inflated common surface. CT (left) and LGI (right) results for IQ2-HC comparison, where each color is associated with different clusters; CT, cortical thickness; LGI, local gyrification; IQ2, intelligence quotient<70; HC, health control.