Researchers using fMRI to study neural activity in IBS patients report that the processing and perception of visceral stimuli can be modulated by psychological and cognitive treatment.
Some studies have shown that gut-directed hypnotherapy can help improve symptoms when incorporated into the treatment of irritable bowel syndrome (IBS). However, according to the authors of “Effect of Hypnotherapy and Educational Intervention on Brain Response to Visceral Stimulus in the Irritable Bowel Syndrome,” published in Alimentary Pharmacology and Therapeutics, despite the successful use of hypnotherapy for the treatment of IBS symptoms, “the neurobiological mechanisms underlying this mind-based therapy remain largely unknown.”
To assess the role of these neurobiological mechanisms, researchers used fMRI to measure brain response to both expected and delivered visceral stimuli (in this case, rectal balloon distension) in IBS patients who had undergone successful hypnotherapy, patients who had completed an IBS-focused educational intervention, and healthy controls. They sought to test whether:
For the study, investigators recruited a cohort of 44 female patients who had a diagnosis of IBS that fulfilled Rome III criteria (29 with IBS-M, 10 with IBS-D, and 5 with IBS-C) whose symptoms had not improved following conventional IBS treatment, and 20 healthy controls. Patients were assigned to undergo hypnotherapy (seven weeks of one-hour sessions delivered by an experienced hypnotherapist) or an IBS educational intervention (seven individual 45-minute sessions delivered by gastroenterologists).
Participants also completed the IBS severity scoring system (IBS SSS), visceral sensitivity index (VSI), Hospital Anxiety and Depression Scale, and a 0-10 scale used to assess the current intensity of gastrointestinal symptoms. Patients also kept gastrointestinal symptom diaries for two weeks pre- and post-treatment.
All participants also completed a fMRI session during which they were monitored “while 18 low- (15 mmHg) and 20 high-intensity (45 mmHg) rectal distension (duration 15 s) were delivered in a pseudorandomised order.”
Following discontinuations for various reasons, investigators obtained complete data from 16 patients who underwent hypnotherapy (HYP), nine patients who completed the educational intervention (EDU), and 18 healthy controls (HC).
The researchers reported that subjects who completed HYP reduced their IBS-SSS score from 342 to 233 (P < 0.0001), and their VSI score from 48 to 34 (P < 0.0001). Subjects who completed EDU reduced their IBS-SSS score from 340 to 256 (P = 0.02) and their VSI score from 48 to 36 (P = 0.005). Thirteen HYP subjects and seven EDU responded to therapy, demonstrating significant decreases in VSI score and GI-symptom intensity and unpleasantness.
In their discussion of the study results, the authors reported:
Based on these results, the investigators concluded that “Gut-directed hypotherapy as well as disease-related education resulted in a clinically significant level of symptom improvement and decreased GI-related anxiety,” which correlated with a reduction in BOLD responses in the ventral and dorsal anterior insula to a high-intensity visceral stimulus. This “demonstrates that the processing and perception of visceral stimuli can be modulated by psychological and cognitive treatment.”