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01-09-2012 | Original Paper

1H-MRS in autism spectrum disorders: a systematic meta-analysis

Authors: Jonathan C. Ipser, Supriya Syal, Judy Bentley, Colleen M. Adnams, Bennie Steyn, Dan J. Stein

Published in: Metabolic Brain Disease | Issue 3/2012

Abstract

We conducted a systematic review and meta-analysis of proton magnetic resonance spectroscopy (1H-MRS) studies comparing autism spectrum disorder (ASD) patients with healthy controls, with the aim of profiling ASD-associated changes in the metabolites N-acetyl-aspartate (NAA) and Creatine (Cr). Meta-regression models of NAA and Cr levels were employed, using data from 20 eligible studies (N = 852), to investigate age-dependent differences in both global brain and region-specific metabolite levels, while controlling for measurement method (Cr-ratio versus absolute concentrations). Decreased NAA concentrations that were specific to children were found for whole-brain grey and white matter. In addition, a significant decrease in NAA was evident across age categories in the parietal cortex, the cerebellum, and the anterior cingulate cortex. Higher levels of Cr were observed for ASD adults than children in global grey matter, with specific increases for adults in the temporal lobe and decreased Cr in the occipital lobe in children. No differences were found for either NAA or Cr in the frontal lobes. These data provide some evidence that ASD is characterized by age-dependent fluctuations in metabolite levels across the whole brain and at the level of specific regions thought to underlie ASD-associated behavioural and affective deficits. Differences in Cr as a function of age and brain region suggests caution in the interpretation of Cr-based ratio measures of metabolites. Despite efforts to control for sources of heterogeneity, considerable variability in metabolite levels was observed in frontal and temporal regions, warranting further investigation.

Although this metabolite is referred to in the literature as creatine (a convention adopted in this review), studies typically assay mixtures of the metabolites creatine and phosphocreatine. Likewise, the mixture of choline-containing compounds that are commonly measured is referred throughout the text as choline.

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Title: 1H-MRS in autism spectrum disorders: a systematic meta-analysis
Authors: Jonathan C. Ipser
Supriya Syal
Judy Bentley
Colleen M. Adnams
Bennie Steyn
Dan J. Stein
Publication date: 01-09-2012
Publisher: Springer US
Published in: Metabolic Brain Disease / Issue 3/2012
Print ISSN: 0885-7490
Electronic ISSN: 1573-7365
DOI: https://doi.org/10.1007/s11011-012-9293-y

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1H-MRS in autism spectrum disorders: a systematic meta-analysis

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