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.