Investigational Use of Neuromuscular Ultrasound

Background: Current techniques used to measure the health and function of a person s nerves and muscles are generally effective, but they do have limits. Researchers are looking for ways to improve the ability to observe nerves and muscles and how they function in this natural history protocol. Objective: To study the use of ultrasound (sound waves) to learn more about nerves and muscles. Eligibility: Healthy adults, aged 18 and older, with no history of stroke, nerve or muscular disorders, or spine surgery are also needed. A smaller population of adults aged 18 and older who have a neuromuscular disorder or show symptoms of nerve or muscle disorder will also be evaluated. Design: Participants will be screened with a medical record review. Participants will have up to 5 outpatient clinic visits. Most participants will have 1 or 2 visits. Visits will last for less than 3-4 hours each. During each visit, participants will give a brief medical history and have a physical exam. Participants will have ultrasounds to get pictures and measurements of their nerves and muscles. Gel will be applied to their skin. A probe will be placed on the skin surface. Sound waves sent through the probe will be used to create pictures. Participants may have nerve conduction studies. Wires will be taped to the skin surface near a muscle or nerve in the arm or leg. The nerve will be stimulated with a small electric current that feels like a rubber band flick. The response will be recorded through the wires.