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Open Access Highly Accessed Research article

White matter connectivity in children with autism spectrum disorders: a tract-based spatial statistics study

Lucia Billeci1, Sara Calderoni2, Michela Tosetti2, Marco Catani3 and Filippo Muratori24*

Author Affiliations

1 Institute of Clinical Physiology, National Council of Research (CNR), Pisa, Italy

2 IRCCS Stella Maris Foundation, Pisa, Italy

3 NatBrainLab, Institute of Psychiatry, King’s College London, London, UK

4 Department of Developmental Medicine, University of Pisa, Pisa, Italy

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BMC Neurology 2012, 12:148  doi:10.1186/1471-2377-12-148

Published: 29 November 2012

Abstract

Background

Autism spectrum disorders (ASD) are associated with widespread alterations in white matter (WM) integrity. However, while a growing body of studies is shedding light on microstructural WM alterations in high-functioning adolescents and adults with ASD, literature is still lacking in information about whole brain structural connectivity in children and low-functioning patients with ASD. This research aims to investigate WM connectivity in ASD children with and without mental retardation compared to typically developing controls (TD).

Methods

Diffusion tensor imaging (DTI) was performed in 22 young children with ASD (mean age: 5.54 years) and 10 controls (mean age: 5.25 years). Data were analysed both using the tract-based spatial statistics (TBSS) and the tractography. Correlations were investigated between the WM microstructure in the identified altered regions and the productive language level.

Results

The TBSS analysis revealed widespread increase of fractional anisotropy (FA) in major WM pathways. The tractographic approach showed an increased fiber length and FA in the cingulum and in the corpus callosum and an increased mean diffusivity in the indirect segments of the right arcuate and the left cingulum. Mean diffusivity was also correlated with expressive language functioning in the left indirect segments of the arcuate fasciculus.

Conclusions

Our study confirmed the presence of several structural connectivity abnormalities in young ASD children. In particular, the TBSS profile of increased FA that characterized the ASD patients extends to children a finding previously detected in ASD toddlers only. The WM integrity abnormalities detected may be relevant to the pathophysiology of ASD, since the structures involved participate in some core atypical characteristics of the disorder.

Keywords:
ASD; TBSS; Tractography; Arcuate fasciculs; Language