Instantaneous Measures of Autonomic Nervous System Responses to Gastrointestinal Challenges

Impaired function of the vagus nerve has been documented in many chronic diseases such as diabetes, heart disease, and chronic pain, as well as gastrointestinal diseases such as irritable bowel syndrome, inflammatory bowel disease, and delayed stomach emptying (gastroparesis).

Current technology only allows for measurement of vagal nerve activity that regulates the heart and diagnostic tests focus specifically on cardiac vagal activity. Measuring vagal nerve activity as it pertains to the gastrointestinal system is an unmet medical need. Its importance will continue to grow since vagal nerve stimulation is being used increasingly in a myriad of different diseases, and currently there is no way of knowing if patients are getting too little or too much stimulation.

In this study, the gastrointestinal vagus nerve will be activated using normal stimulants like food ingestion and vagal activity will be measured using current non-invasive technology. Patients with gastroparesis and healthy controls will be asked to come in fasting, fill out surveys, and complete eating challenges while being connected to an autonomic function testing machine. Exploratory outcomes will also be measured - Participants will be connected to a Peripheral Intravenous Line in order to collect four vials of blood throughout the two hour clinic visit so that hormonal changes can be studied. Also, exploratory non-invasive electrogastrograms will be recorded remotely both during the autonomic function test and for three consecutive days as participants go about their daily lives.

The investigators' goal is to establish a protocol for measuring gastrointestinal evoked vagal activity and correlating activity with digestive function in both healthy people and gastroparesis patients.