Gray matter abnormalities in autism spectrum disorder revealed by T2 relaxation - Reply

Department of Psychology, University of Washington Seattle, Seattle, Washington, United States
Neurology (Impact Factor: 8.29). 09/2006; 67(4):632-6. DOI: 10.1212/01.wnl.0000229923.08213.1e
Source: PubMed

ABSTRACT To perform quantitative T2 relaxation measurements to evaluate cerebral water content in children with autism.
Sixty 2- to 4-year-old children with autism spectrum disorder (ASD), 16 age-matched children with idiopathic developmental delay (DD), and 10 children with typical development (TD) were scanned on a 1.5 T GE MRI scanner to obtain dual-echo fast spin echo images (2.5 mm thick, 0-mm gap). Images were segmented into gray and white matter and used to mask regions of interest for calculating T2 for each tissue type. Analysis of variance, covarying for age and sex, was used to compare T2 between groups, and correlations were used to compare T2 to IQ measures.
Children with ASD had prolonged cortical gray matter T2, but white matter T2 was not significantly different, compared with the children with TD. T2 was prolonged in cortical gray matter and white matter in children with DD compared with children with ASD or TD. Significant interactions between T2 measures and IQ were not observed.
Prolonged gray and white matter T2 in the children with developmental delay likely represents a delay in neuronal development and maturation. Prolonged T2 in gray matter, but not white matter, observed in children with autism spectrum disorder may signify abnormal developmental processes specific to autism.

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Available from: Dennis W W Shaw, Sep 29, 2015
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    • "Abnormal growth was most pronounced in temporal grey matter volumes consistent with earlier findings in children with ASD under the age of two [114] and over [95, 106]. Therefore, abnormal early development of grey matter is linked with ASD (i.e., [115]) in children between two and four years old. Numerous conditions of atypical development can lead to autism, in particular fragile X syndrome (FXS), which is considered to be the most commonly known single-gene cause of autism. "
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    • "In previously reported work (Sparks et al., 2002), cerebral and cerebellum volumes were obtained using a stereotaxic grid (Gunderson & Jensen, 1987). In the current study, cerebral and cerebellar measurements were obtained using a semiautomated histogram approach to improve measurement sensitivity for small volume differences (Friedman et al., 2006; Petropoulos et al., 2006). Cerebral volume included the basal ganglia and corpus callosum, and excluded the ventricles, brain stem and cerebellum. "
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