Vagus nerve ultrasound

Study Purpose

The purpose of the study is to measure the size of the nerve called Vagus nerve in patients with PD and MSA who have symptoms of autonomic dysfunction (feeling of fainting when standing up from sitting, constipation, decreased sweating, urinary incontinence or frequency) using a procedure that uses high-energy sound waves to look at tissues and organs inside the body called ultrasound. We aim to compare the size of the nerve with regular autonomic testing by measuring change in heart rate with deep breathing and Valsalva maneuver. We will also compare the change in size of the pupil and compare it with the other tests measuring parasympathetic function. We also want to see if the bedside ultrasound can be used along with our regular autonomic tests to look directly at the Vagus nerve and study heart rhythms controlled by the parasympathetic nervous system and compare it with the change in pupil size.

Who Can Participate

Healthy Volunteer: Age: 18 years and older Neuromuscular Disease: Age: 40-89 years old