Wednesday, June 30, 2010

Study: Regional Gray Matter Density Changes in Brains of Patients With Irritable Bowel Syndrome

Written by Anthony Hardie

( – There are visible changes in the gray matter of the brain in patients with Irritable Bowel Syndrome – a presumptive condition for service-connection for veterans with service in the Gulf War – says a new study published this month in Gastroenterology, the official journal of the American Gastroenterology Institute.

Using advanced brain imaging technology, the study found that patients with IBS had common changes in their brains’, with widespread areas of decreased grey matter density.

The areas of the brain affected are involved in cognitive/evaluative functions.

Study subjects were divided between controls without IBS and various subgroups of IBS patients separated based on their  most significant IBS symptoms.

The abstract of the study is below.


Background & Aims

Several studies have examined structural brain changes associated with chronic pain syndromes, including irritable bowel syndrome (IBS), but study sample sizes have been small and heterogeneous.


We used magnetic resonance imaging–based techniques, voxel-based morphometry, and cortical thickness analysis to examine brain anatomical differences in a relatively large, tightly screened sample of IBS patients (n = 55); we compared data with that from healthy persons (controls; n = 48).


IBS was associated with decreased gray matter density (GMD) in widespread areas of the brain, including medial prefrontal and ventrolateral prefrontal cortex, posterior parietal cortex, ventral striatum, and thalamus. Compared with controls, we observed increased GMD in patients with IBS in the pregenual anterior cingulate cortex and the orbitofrontal cortex, as well as trends in the posterior insula/secondary somatosensory cortex, (para)hippocampus, and left dorsolateral prefrontal cortex. In accounting for anxiety and depression, we found that several of the regions involved in affective processing no longer differed between patients with IBS and controls, whereas the differences in prefrontal and posterior parietal cortices remained. The areas of decreased GMD associated with IBS were largely consistent across clinical subgroups, based on predominant bowel habit and pain predominance of symptoms. No overall or regional differences were observed in cortical thickness between patients with IBS and controls.


Changes in density of gray matter among regions involved in cognitive/evaluative functions are specifically observed in patients with IBS, whereas changes in other areas of the brain can be explained by levels of anxiety and depression.

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