Treatment of Abdominal Distension by Biofeedback - a Randomized Controlled Trial

• Bloating sensation [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  Bloating sensation will be assessed by means of a graphic rating scale graded from 0 (no perception) to 6 (very intense perception).
• Reduction of internal oblique electromyography activity [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
  Electromyographic activity of the abdominal wall (external oblique, internal oblique, upper rectus, lower rectus) will be continuously measured using 4 pairs of surface electrodes. The outcome measurement takes place after 30 minutes of treatment session.
• Decrease of abdominal girth [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
  Abdominal girth will be continuously measured using a nonstretch belt (48mm wide) that is placed over the umbilicus and fixed to the skin on the back to prevent slipping. The overlapping ends of the belt will be adjusted carefully with two elastic bands to adapt constantly to the abdominal wall. The outcome measurement takes place after 30 minutes of treatment session.

• Bloating sensation [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]
  Bloating sensation will be assessed by means of a graphic rating scale graded from 0 (no perception) to 6 (very intense perception).
• Reduction of internal oblique EMG activity [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
  Electromyographic activity of the abdominal wall (external oblique, internal oblique, upper rectus, lower rectus) will be continuously measured using 4 pairs of surface electrodes. The outcome measurement takes place after 30 mintues of treatment session.
• Decrease of abdominal girth [ Time Frame: 30 minutes ] [ Designated as safety issue: No ]
  Abdominal girth will be continuously measured using a nonstretch belt (48mm wide) that is placed over the umbilicus and fixed to the skin on the back to prevent slipping. The overlapping ends of the belt will be adjusted carefully with two elastic bands to adapt constantly to the abdominal wall. The outcome measurement takes place after 30 mintues of treatment session.

Background: Abdominal bloating is a frequent and bothersome complaint in patients with functional gut disorders without satisfactory treatment to date. Recent data from our laboratory indicate that abdominal distention in these patients is produced by abdomino-phrenic dyssynergia: diaphragmatic contraction associated with abdominal wall relaxation (particularly the internal oblique). In analogy to other clinical situations (e.g. functional outlet obstruction, rumination or aerophagia) behavioral treatment by means of biofeedback might be equally effective in these patients. The investigators hypothesized that abdomino-phrenic coordination and abdominal distention can be controlled by biofeedback techniques.

Aims: Based on the investigators hypothesis, the investigators plan the following milestones: a) to prove the efficacy of behavioural treatment using biofeedback techniques for abdominal distension, and b) identify biological markers that may predict the response to treatment.

Randomization: Patients will be randomized by a 2:1 (Feedback : Placebo) randomization, stratified by gender.

Intervention: Feedback: Patients will be taught thoracic inspiration with bio-feedback using online electromyography information. The training session will last 15 min. Placebo: Patients will be given a pill containing Dimeticon-Siliciumdioxid (Simethicon).

Measurements: In the erect position, electromyographic activity of the diaphragm, the anterior abdominal wall, and the intercostal muscles will be continuously recorded. Abdominal distension will be measured by a metric tape fixed to a non-stretch belt placed over the umbilicus. Conscious perception will be assessed by means of graphic rating scales graded from 0 (no perception) to 6 (very intense sensation).

Outcomes: Primary outcome: Reduction of electromyographic muscle activity of the diaphragm and the internal oblique Secondary outcome: Reduction of bloating sensation.

Follow-up: Patients will be followed for 3 months after the initial treatment session.

• Abdominal Distention
• Irritable Bowel Syndrome
• Functional Bloating

• Behavioral: Bio-feedback assisted respiratory maneuvers
  By providing on-line electromyography information of muscle activity, patients will be able to control and actively correct their muscle activity during the 15 min treatment session. Each patients will attend 3 treatment sessions.
• Drug: Placebo medication
  Patients will take a pill that contains Dimetico-Siliciumdioxid (Simethicon). Dimetico-Siliciumdioxid is an anti-foaming agent that decreases surface tension of gas bubbles and is used as a gold-standard in the treatment of patients with abdominal bloating and distension. However, recent studies have shown that the amount of intestinal gas does not change during spontaneous bloating in patients with irritable bowel syndrome and functional bloating. Therefore, we do not expect the drug to have any effect. Respiratory maneuvers will not be performed and no electromyography information will be provided.

• Active Comparator: Feedback
  Patients will be taught to control abdominal and diaphragmatic muscles by bio-feedback.
  Intervention: Behavioral: Bio-feedback assisted respiratory maneuvers
• Placebo Comparator: Placebo
  Patients will be given a pill containing Dimeticon-Siliciumdioxid (Simethicon).
  Intervention: Drug: Placebo medication

• Tremolaterra F, Villoria A, Azpiroz F, Serra J, Aguadé S, Malagelada JR. Impaired viscerosomatic reflexes and abdominal-wall dystony associated with bloating. Gastroenterology. 2006 Apr;130(4):1062-8.
• Villoria A, Azpiroz F, Soldevilla A, Perez F, Malagelada JR. Abdominal accommodation: a coordinated adaptation of the abdominal wall to its content. Am J Gastroenterol. 2008 Nov;103(11):2807-15. Epub 2008 Sep 10.

Inclusion Criteria:

• Abdominal distension in irritable bowel syndrome or functional bloating (according to Rome III criteria)

Exclusion Criteria:

• Age 18 over younger
• Gastrointestinal motility disorder
• Not meeting Rome III criteria