Objective: To identify a central hub of visceral pain in IBS-D and elucidate the mechanism by which repetitive transcranial magnetic stimulation (rTMS) confers analgesic effects. Design: Combined functional magnetic resonance imaging (fMRI) with visceral sensitivity assessments were used to pinpoint hyperactive brain regions of IBS-D patients. Therefore, a clinical trial was performed to validate the therapeutic potential of rTMS in IBS-D patients.
Background:Chronic visceral pain in irritable bowel syndrome with diarrhea (IBS-D) is a profound therapeutic challenge. While aberrant central processing is implicated, the key brain regions driving this visceral pain and their suitability as neuromodulatory targets remain undefined. Methods:Participants were randomly assigned (1:1) to the sham rTMS or rTMS group using a computer-generated randomization sequence created by an independent researcher who was not involved in recruitment, treatment, or outcome assessment. Allocation concealment was ensured using sequentially numbered, opaque, sealed envelopes, which were opened only after baseline evaluations were completed. Both participants and outcome assessors were blinded to treatment allocation. The rTMS operators were not involved in data collection or analysis. For the sham condition, the coil was positioned identically over the mPFC with magnetic output disabled, and prerecorded clicking sounds were delivered to mimic the acoustic sensation of stimulation. Participants were asked not to discuss treatment sensations with assessors. Scale raters and fMRI analysts remained blinded until all analyses were finalized. For the nested fMRI cohort, randomization and blinding procedures were identical, with group allocation revealed only after preprocessing and statistical analysis had been completed.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
42
Patients with IBS-D received repetitive transcranial magnetic stimulation at 1 Hz/s for 20 minutes for 2 week.
For the sham rTMS group, the coil was placed over the mPFC with the rTMS function disabled, and pre-recorded acoustic artifacts were played to mimic the auditory experience of the rTMS group.
The First Affiliated Hospital of Soochow University
Suzhou, Jiangsu, China
IBS-symptom severity score
The criteria were based on the IBS Symptom Severity Score (IBS-SSS), a hierarchical efficacy assessment method.The IBS-SSS consists of five entries assessing the degree of abdominal pain and discomfort, frequency of abdominal pain episodes, the degree of abdominal distension and discomfort, the degree of satisfaction with bowel habits and behaviors, and the degree of impact of intestinal symptoms on life,with a total score of 500 points. A score of 75-175 is considered mild, 176-300 is moderate, and over 300 is severe. Cure was defined as a total IBS symptom severity of less than 75; efficacy was defined as 2-level improvement in total score(e.g., symptoms improved from severe to mild); validity was defined as a 1-level improvement in tatal(e.g., symptoms improved from severe to moderate or symptoms from moderate to mild); and invalidity was defined as no improvement or deterioration in total score.
Time frame: Assessment time points were: baseline (1 week pre-treatment), end of the 2-week treatment, and post-treatment weeks 1, 2, 4, and 8.
anorectal manometry
Anorectal manometry was performed on the subjects before and after treatment and the subjects' rectal primary sensory thresholds were recorded. Rectal initial sensory thresholds between 20-90ml were considered normal , less than 20ml was considered as sensitivity rectal sensory, and cure meant that the IBS patients had their rectal initial sensory recordings restored to between 20-90ml.
Time frame: Assessment time points were: baseline (1 week pre-treatment), end of the 2-week treatment, and post-treatment weeks 4 and 8.
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