Visible Abdominal Distension

Three sessions of biofeedback intervention will be performed during the first 3 weeks of the intervention period. Patients will be taught to control abdominal and thoracic muscular activity by providing instructions using an original video support. Patients will be instructed to perform the same exercises before and after breakfast, lunch and dinner during the 4-week intervention period

Three sessions of placebo intervention will be performed during the first 3 weeks of the intervention period. Sham measurements of abdominal and thoracic motion will be performed, and a pill of placebo containing 0.21 g glucose will be administered; patients will be instructed to take a pill of placebo before breakfast, lunch and dinner during the 4-week intervention period.