The purpose of this study is to find out if we can gain access to the vagus nerve which is largely an internal nerve that controls stomach function. We hope to gain access to the internal vagus nerve by electrically stimulating the nerve around the external ear. If we can do this then we hope that this will help our treatment of patients with nausea and vomiting and disordered stomach function
Subjects will undergo transcutaneous stimulation of the auricular branch of the vagus nerve and also undergo blood draw before, after stimulation and later a third draw after a period of no stimulation. Healthy subjects will also undergo vagal maneuver using the Multi Array Electrodes (MEA). Gastroparetic subjects will also undergo vagal maneuver using either the regular EKG electrodes or the MEA electrodes. Subjects will also complete health history questionnaires.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
120
Electrical stimulation electrodes will be placed on the ear with the intensity of the current being increased by 10 percent every 60 seconds, the subject will grade the intensity of the current on a scale of 0-10. Increasing of the current will occur until the subject reports a comfortable level. Once the target level has been achieved the stimulation will be delivered for 2 minutes.
Subjects will undergo the following procedures to stimulate the vagus nerve. * Cough: 6 to 8 forceful coughs * Cold stimulus: a washcloth soaked in ice water will be placed on the face for 10 seconds. * Carotid massage * Gagging: a tongue depressor will be inserted for 10 seconds into the mouth touching the back of the mouth. * Valsalva maneuver: subjects will will be asked to bear down as if they were having a bowel movement. They will be asked to blow through a mouthpiece that is hooked to a machine that measures how hard they are blowing. * Eating: Subjects will be asked to drink water ( 8oz or 1 cup) or/ and Ensure Original ( 8 oz or 1 cup) that has 220 calories after fasting overnight to see that effect on vagal activity during eating.
Indiana University
Indianapolis, Indiana, United States
RECRUITINGAmplitude of vagal nerve compound action
To measure the amplitude of vagal nerve compound action potentials during stimulation of the auricular branch of the vagal nerve and during vagal maneuvers.
Time frame: 3 hours
Respiratory Changes in heart rate during stimulation
To measure respiratory changes in heart rate during stimulation of the auricular branch of the vagal nerve and also during the vagal maneuvers phase.
Time frame: 3 hours
Changes in amplitude of the surface electrogastrogram
To measure the changes of surface electrogastogram during stimulation of the auricular branch of the vagal nerve and also during the vagal maneuvers phase.
Time frame: 3 hours.
Changes in gastric hormones
To measure the effect of stimulation of the auricular branch of the vagal nerve and/or of vagal maneuvers on gastric hormones.
Time frame: 3 hours.
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