Gastric Focused Ultrasound Stimulation

This randomized, sham-controlled crossover pilot study will evaluate whether noninvasive gastric focused ultrasound stimulation is associated with changes in postprandial gastric electrical activity and gastrointestinal symptoms in adults with gastroparesis or delayed gastric emptying. Participants will complete one active FUS visit and one sham-stimulation visit in randomized order, separated by at least 48 hours. At each visit, electrogastrography will be recorded before and after a standardized liquid nutritional drink, during active or sham stimulation, and during recovery. Gastrointestinal symptoms will be assessed at prespecified time points using the Total Symptom Score questionnaire.

Inclusion Criteria: * Age 18 to 70 years. * Delayed gastric emptying or gastroparesis diagnosed by a clinician and confirmed by gastric emptying scintigraphy or a gastric emptying breath test. * Ability to understand the study procedures, provide informed consent, and complete two study visits. * Ability to consume the two bottles of Ensure or Glucerna nutritional drink used in the study. Exclusion Criteria: * Pregnancy. * Epilepsy. * Cardiac pacemaker or another implanted electronic medical device. * Peritoneal dialysis. * Daily use of narcotic or opioid medications. * Abdominal wall ulcers, open wounds, active infection, or significant skin irritation in the area where the electrogastrography electrodes or focused ultrasound transducer will be placed. * Known allergy or contraindication to the available Ensure or Glucerna nutritional drinks. * Any other medical or safety condition that, in the judgment of the study team, would make participation unsafe. Medication Restrictions: Participants using medications that may significantly affect gastric motility or gastric emptying may be rescheduled if those medications were used within the study-defined restriction period. Relevant medications include opioid analgesics, prokinetic agents, anticholinergic or antispasmodic agents, GLP-1 receptor agonists or related medications, and anti-nausea or antiemetic medications that may affect gastrointestinal function. Participants should not discontinue any medically necessary medication without first consulting their treating physician.