Abdominothoracic Muscular Tone in Functional Dyspepsia

Background. Patients with functional dyspepsia report symptoms after eating without detectable cause. A recent proof-of-concept study demonstrated that in healthy subjects, the activity of the abdominal walls influences perception of digestive sensations, specifically, intentional abdominal distension (by a maneuver of diaphragmatic contraction) increased bloating sensation in response to a probe meal. Aim. To determine the role of the abdominothoracic muscular activity on symptoms of functional dyspepsia. Design. Parallel study in dyspeptic patients who have an abnormal somatic response to a probe meal (experimental group), and patients who do not (control group), comparing the effect of abdominophrenic biofeedback on dyspeptic symptoms. The probe meal will consist in stepwise ingestion of a comfort meal (hot ham and cheese sandwich plus orange juice) up to maximal satiation. Intervention. A standard biofeedback technique (3 sessions over a 4-week period) directed at controlling the muscular activity (postural tone) of the abdominal walls, will serve as active intervention in the experimental group, and as a sham intervention in the control (active comparator) group. The study outcomes will be measured before, immediately after and at 6 months after biofeedback: 1) Clinical symptoms measured by scales during 7 consecutive days. 2) Responses to the probe meal: (a) sensations measured by scales; (b) changes in girth by adaptive belts; (c) diaphragmatic position by abdominal ultrasound. Relevance. The identification of a pathophysiological mechanism of dyspeptic symptoms could serve as an objective marker for diagnosis and as a target for the development of mechanistic treatments.

Adaptive design: a sample size calculation based on the primary outcome will be performed after 30 patients complete the post-intervention evaluation.

A standard biofeedback technique (3 sessions over a 4-week period) directed at controlling the muscular activity (postural tone) of the abdominal walls, will serve as active intervention in the experimental group, and as a sham intervention in the active comparator group.

Change in postprandial fullness (measured on daily postprandial fullness scales graded from 0, i.e., not at all, to 10, i.e., extremely severe) during 7 consecutive days before and immediately after intervention.

Change in digestive well-being after a probe meal (measured on a scale graded from -5, i.e., extremely negative, to +5, i.e., extremely positive) before and after intervention

Change in postprandial fullness after a probe meal (measured on a scale graded from 0, i.e., not at all, to 10, i.e., extremely severe) before and after intervention

Changes in the girth response to a probe meal (measured by adaptive belts) before and after intervention.

Changes in the diaphragmatic response to a probe meal (measured by ultrasound) before and after intervention.

Inclusion Criteria: Rome IV Criteria for functional dyspepsia Exclusion Criteria: organic gastrointestinal diseases obesity history of anosmia and ageusia alcohol abuse eating disorders Age- and-sex-matched healthy subjects will be included in parallel to the 30 first patients, to determine the normal values of the response to the probe meal. Healthy subjects will not undergo the intervention.

Livovsky DM, Barber C, Barba E, Accarino A, Azpiroz F. Abdominothoracic Postural Tone Influences the Sensations Induced by Meal Ingestion. Nutrients. 2021 Feb 18;13(2):658. doi: 10.3390/nu13020658.