Because we included measures of visceral sensitivity and pain during rectal stimulation in the study above (22) using the barostat method, this paper explores bidirectional gut-brain interactions by means of a top-down (i.e., brain initiated) intervention in subjects with IBS.
The aim of the present pilot study was to elucidate whether or not a cognitive-behavioral intervention for IBS affects (1) visceral sensitivity and pain during rectal stimuli using the barostat method in subjects with IBS and (2) self-rated visceral sensitivity and fear and worry about symptoms, as well as gastrointestinal symptoms in patients with IBS.
The study included 18 subjects with IBS whose ratings of visceral pain, urge, and discomfort as well as the induced visceral pressure (mmHg) during rectal distensions with the barostat method were measured four weeks before the CBT intervention (t1, n = 8) and/or just before the CBT intervention (t2, N = 15) as well as after the intervention (t3, N = 15).
Twelve participants performed a four-week baseline and six participants started treatment directly within a week from the first barostat assessment.
The pressure (mmHg) of the barostat was measured but in order to achieve better comparability across subjects it was normalized based on 20, 40, 60, and 80% of the largest fitted VAS score using fits of logistic functions with intercept (see below).
For the barostat analysis, data from three subjects could not be analyzed because of technical limitations during the barostat assessment; this left a total of 15 participants for the barostat analysis.
The present study used for the first time the barostat technique to assess a biological marker of visceral pain and indicated that CBT effects arise primarily via psychological coping of IBS symptoms rather than visceral-afferent signaling of decreased symptoms.
Although we found a significant effect of CBT on IBS symptomatology in another report with these same participants, our sample size may be too small for physiological measures, for example, barostat assessment of visceral pain.
The present study investigated for the first time whether CBT for IBS alters visceral sensitivity, pain, and the maximal tolerable pressure during rectal stimuli using the barostat method.
Kilkens et al., "Alternative procedure to shorten rectal barostat procedure for the assessment of rectal compliance and visceral perception: a feasibility study," Journal of Gastroenterology, vol.