International Meeting for Autism Research: Longitudinal Surface Morphometry Changes in Children with Autism

Longitudinal Surface Morphometry Changes in Children with Autism

Friday, May 21, 2010
Franklin Hall B Level 4 (Philadelphia Marriott Downtown)
9:00 AM
D. S. Hong , Department of Psychiatry, Stanford University, Stanford, CA
N. J. Minshew , Psychiatry and Neurology--Center for Excellence in Autism Research, University of Pittsburgh School of Medicine, Pittsburgh, PA
M. S. Keshavan , Department of Psychiatry, Harvard Medical School, Boston, MA
A. Y. Hardan , Division of Child and Adolescent Psychiatry, Stanford University School of Medicine/Lucile Packard Children's Hospital, Stanford, CA
Background: Cortical folding and gyrification are closely associated with the establishment of neuronal connections early in brain development. Advances in techniques to measure surface morphometry have shown promise in defining markers of pathological change of this process. Several studies have indicated that this aspect of neural development may be dysregulated in autism, including findings of increased cortical folding in frontal regions and excessive decrease in cortical thickness over a longitudinal course in childhood. However, no previous study has specifically examined the role of sulcal and gyral area and curvature in autism. A surface-based morphometric approach may yield more information, especially in light of data from functional imaging studies implicating frontal and temporal sulcal anatomy in social cognition. Additionally, these measures may provide more insight on the pathophsysiology of autism compared to volumetric analyses..
Objectives: The primary purpose of this longitudinal study was to examine developmental changes in sulcal and gyral anatomy in children with autism, utilizing magnetic resonance imaging (MRI).
Methods: Participants included male children with autism and age- and gender-matched controls, between the ages of 8-12 years at baseline. Diagnosis was confirmed utilizing expert clinical evaluation and through structured research diagnostic instruments, the Autism Diagnostic Interview- Revised and the Autism Diagnostic Observation Schedule. Scans were obtained using the same acquisition protocol at baseline and follow-up. All scans were obtained on the same GE 1.5-Tesla Signa whole-body MRI system. Image processing of MRI scans was done on a SGI workstation, utilizing Brain Research: Analysis of Images, Networks and Systems software (BRAINS2), which was used to generate sulcal and gyral area and curvature measurements. Between-group differences in demographic data were analyzed with two-tailed Student’s t tests. Within-group differences of neurobiological measurements over time were analyzed using paired t-tests.
Results: 18 boys with autism (mean age=10.9, SD=1.2) and 16 healthy control boys (mean age=10.7, SD=1.2) participated in this study. No differences were observed between participants in the autism and the control group on any of the demographic characteristics except for FSIQ. Mean time difference between the baseline and follow-up scans was 2.1 years with no significant difference in the time interval between the two groups (t=1.414, p=0.167). Over time, boys with autism showed a significant increase overall surface area of temporal gyri (t=-.4.519, p=0.000), as well as significant changes in parietal sulci (t=-2.341,p=0.032) and total sulcal curvature (t=-2.279, p=0.036). Controls only demonstrated a longitudinal increase in temporal sulcal (t=-3.105, p=0.006) and gyral (t=-2.325, p=0.032) surface areas.
Conclusions: Abnormal developmental changes in sulcal and gyral area and curvature were found in this sample of children with autism. These preliminary findings are consistent with previous observations that morphological changes at the level of sulci and gyri reflect underlying white matter structural abnormalities. Furthermore, the pattern observed here is suggestive of alterations of short- and long-distance neuronal connections. Additional studies are needed to elucidate this correlation between regional surface morphology with deeper cortical structure and function.
See more of: Brain Imaging
See more of: Brain Imaging
See more of: Brain Structure & Function