This is a clinical trial of a non-invasive BSGM medical device (Gastric Alimetry) in patients with medical refractory GORD and healthy controls to determine the differences in gastric electrical activity, and correlate with adjacent measurements of gastro-esophageal function.~Patients referred to the Functional Gut Clinic for standard care investigation of GORD with HRM and pH-impedance monitoring will be recruited. Healthy volunteers will be recruited via advertisement.~All patients and healthy volunteers will undergo BSGM at the research site, which lasts around 4.5 hours. After a 0.5 hour baseline, subjects will undergo HRM and pH-impedance monitoring concomitantly. A test meal of porridge with C13 labelled octanoic acid will be consumed with BSGM and breath samples recorded for 4.0 hours after meal completion. The HRM catheter will be removed after 1.0 hour from finishing the test meal whist the pH-impedance monitoring will continue for the remainder of the site visit and for the remainder of the 24-hour study period whilst the subject is at home to quantify reflux.
Bodysurface gastric mapping (BSGM) will be used to assess gastric neuromuscular function in healthy controls and patients with medical refractory gastroesophageal reflux disease (GERD).~Participants will undergo BSGM for 4-hours in addition to high resolution manometry (HRM), pH-impedance monitoring, and gastric emptying breath test.