Beyond the Snapshot: Overcoming GES Limitations to Characterize Gastric Phenotypes and Therapeutic Responses Using a 6‐Day Ambulatory Wearable Monitor

BACKGROUND: Gastric emptying scintigraphy (GES) is considered the standard for differentiating gastroparesis from functional dyspepsia and other foregut disorders characterized by nausea and vomiting but provides only a brief physiologic snapshot that may not accurately reflect daily function. We utilized a non-invasive wireless patch system (WPS) to characterize multiday gastric myoelectrical activity, evaluate its relationship with GES, and assess changes following a therapeutic intervention. METHODS: Adults referred for GES for symptoms thought to represent gastroparesis were enrolled in a prospective study. Patients wore a WPS for up to 6 days, starting on the day of scintigraphy. Gastric myoelectrical activity was analyzed and categorized into relatively weak, relatively moderate, and relatively strong activity phenotypes. A subset of patients underwent repeat monitoring following individualized therapeutic interventions (e.g., anti-emetics, proton pump inhibitors, lifestyle changes). RESULTS: Forty-eight patients (mean age 44; 79% female) completed the study. GES identified delayed gastric emptying in 18%, rapid in 22%, and normal in 60% of subjects. During the 4-h concurrent GES window, gastric activity in patients with delayed emptying was lower, but this difference did not reach statistical significance (p = 0.08). When compared to the full multiday recording period, GES results showed no correlation with the myoelectric readings. Significant day-to-day variability was observed, both random and systemic. In the latter category, a "Test-Day" dip was observed with gastric activity lowest on Day 1 (GES test day) and increasing significantly on subsequent days, stabilizing by Day 4 (p < 0.001). Healthy control subjects recorded during normal daily routines showed no such day-to-day variation. In the retesting cohort, anti-emetics produced robust increases in gastric amplitude, whereas PPIs showed minimal impact. CONCLUSIONS: The WPS effectively captures distinct gastric phenotypes and quantifies physiologic responses to therapy in both gastric and intestinal regions, demonstrating its clinical utility as a robust tool for evaluating and managing foregut symptoms in real-world settings. Importantly, the multiday WPS highlights significant day-to-day physiologic variability in gastric activity that extends beyond the single-day GES 'snapshot'.