Treatment of Abdominal Distension by Biofeedback - a Randomized Controlled Trial

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. Aim: to prove the efficacy of behavioural treatment using biofeedback techniques for abdominal distension. Randomization: Patients will be randomized into biofeedback and placebo groups. Intervention. Biofeedback: patients will be taught to control abdominothoracic muscular activity by bio-feedback using online electromyography information. Placebo: patients will be given a pill containing placebo medication. Interventions will be delivered in 3 sessions (20 min each) over 10-day period . Measurements: Sensation of abdominal distension will be assessed by means of graphic rating scales graded from 0 (no perception) to 6 (very intense sensation). The activity of the abdomino-thoracic muscles will be recorded. Abdominal distension will be measured by a metric tape fixed to a non-stretch belt placed over the umbilicus. Outcomes: Primary outcome: Change in sensation of abdominal sensation. Secondary outcomes: a) changes in thoraco-abdominal activity of the muscular walls; activity of thoraco-abdominal muscles (intercostals, diaphragm, external oblique, internal oblique, upper rectus, lower rectus) will be measured by electromyography; b) changes in girth; abdominal girth will be measured using a nonstretch belt (48mm wide) that is placed over the umbilicus. The overlapping ends of the belt will be adjusted carefully with two elastic bands to adapt constantly to the abdominal wall.

Patients will be taught to control abdominal and diaphragmatic muscles by bio-feedback using EMG recordings.

Electromyography will be recorded but not shown to the patients. Patients will take a pill of placebo.

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.

Sensation score measured by 0-6 scales after each meal (breakfast, lunch, dinner) over a 10-day clinical evaluation period before and after intervention.

Activity of thoraco-abdominal muscles (intercostals, diaphragm, external oblique, internal oblique, upper rectus, lower rectus) will be continuously measured by electromyography.

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. Measurements will be taken before and at the beginning at the end of each intervention session.

Inclusion Criteria: episodes of visible abdominal distension triggered by meal ingestion Exclusion Criteria: organic cause detected by clinical work-up

Tremolaterra F, Villoria A, Azpiroz F, Serra J, Aguade S, Malagelada JR. Impaired viscerosomatic reflexes and abdominal-wall dystony associated with bloating. Gastroenterology. 2006 Apr;130(4):1062-8. doi: 10.1053/j.gastro.2005.12.036.

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. doi: 10.1111/j.1572-0241.2008.02141.x. Epub 2008 Sep 10.

Barba E, Accarino A, Azpiroz F. Correction of Abdominal Distention by Biofeedback-Guided Control of Abdominothoracic Muscular Activity in a Randomized, Placebo-Controlled Trial. Clin Gastroenterol Hepatol. 2017 Dec;15(12):1922-1929. doi: 10.1016/j.cgh.2017.06.052. Epub 2017 Jul 11.