High Resolution, Noninvasive Measurement and Functional Classification of Vagal Nerve Response Patterns in Relation to Gastroparesis Symptom Management Using Gastric Electrical Stimulation Therapy

During Phase

1, in a small cohort of 5-10 gastroparetic patients receiving GES therapy, we will determine the optimal multielectrode array (MEA) recording electrode configuration (e.g., surface area covered and electrode density) for the noninvasive measurement of gastric electrical stimulation (GES) evoked compound nerve action potentials (CNAP) from the skin surface over the left and right cervical vagus nerve. During Phase 2, a study of 15-30 gastroparetic patients receiving GES therapy, we will use the optimal MEA configuration identified in Task 1 to measure and classify the vagal CNAP response signature (including the direction of travel and anatomical location of the strongest signal (e.g., to infer the anatomical course of the cervical vagus in each subject) with respect to subject-reported symptom scores via the 9-item Gastroparesis Cardinal Symptom Index (GCSI) survey. We will cross-reference these results with the preliminary results obtained with bipolar ECG electrodes.

Phase 1:

Subjects will complete a symptom survey questionnaire and Gastric Cardinal Symptom Index (GCSI) questionnaire. Two electrocardiography (ECG) electrodes will be placed on both sides of the neck overlying the area near the carotid pulse (which overlies the carotid artery in the neck on the side of your neck) where the vagus nerve is located.This is done in order to measure the vagal nerve electrical impulses in the neck (electrical signal travelling in the nerve).

Two ECG electrodes will be placed on each of the arms and one on the chest for measurement of electrocardiogram (ECG) ( a test to measure the electrical activity of your heart). Three ECG electrodes may be placed on the stomach to measure the electrical activity of the stomach.