Pooled analysis of brain activity in irritable bowel syndrome and controls during rectal balloon distension

Authors

  • J. Sheehan,

    1. Department of Medicine, GI Unit, Massachusetts General Hospital, Harvard Medical School, Martinos Center for Biomedical Imaging, Boston, MA, USA
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  • A. Gaman,

    1. Department of Medicine, GI Unit, Massachusetts General Hospital, Harvard Medical School, Martinos Center for Biomedical Imaging, Boston, MA, USA
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  • M. Vangel,

    1. Department of Medicine, GI Unit, Massachusetts General Hospital, Harvard Medical School, Martinos Center for Biomedical Imaging, Boston, MA, USA
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  • B. Kuo

    1. Department of Medicine, GI Unit, Massachusetts General Hospital, Harvard Medical School, Martinos Center for Biomedical Imaging, Boston, MA, USA
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Address for Correspondence
Braden Kuo, MD, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
Tel: +617 724 6038; fax: +617 724 1091;
e-mail: bkuo@partners.org

Abstract

Background  Brain-imaging literature of irritable bowel syndrome (IBS) suggests an abnormal brain–gut communication. We analyzed the literature to evaluate and compare the aspects of brain activity in individuals with IBS and control subjects experiencing controlled rectal stimulation.

Methods  PubMed was searched until September 2010. Data from 16 articles reporting brain activity during rectal balloon distensions in IBS compared to control groups was analyzed. Prevalence rates and pairwise activations were assessed using binomial distributions for 11 selected regions of interest. The data were aggregated to adjust for center effect.

Key Results  There was considerable variability in the literature regarding regions and their activity patterns in controls and individuals with IBS. There was no significant difference found in the thalamus, anterior cingulate cortex, posterior cingulate cortex, and prefrontal cortex, however, results show limited evidence of consensus for the anterior insula (AI) (= 0.22). Pairwise activity results suggest that pairs involving the AI tend to have more consistent activity together than pairs which do not involve the AI (posterior insula and AI, = 0.08; posterior cingulate cortex and AI, = 0.16), however, no pairwise evaluation reached significance.

Conclusions & Inferences  Our pooled analysis demonstrates that the literature reports are quite heterogeneous but there is some evidence that there may be patterns of higher activity more common in individuals with IBS than in controls. A consensus, though, regarding study designs, analysis approach and reporting could create a clearer understanding of brain involvement in IBS pathophysiology.

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