Electrical Impedance Myography: Natural History Studies inNeuromuscular Disorders and Healthy Volunteers

* INCLUSION CRITERIA: HEALTHY VOLUNTEERS-ADULTS 1. Healthy adults, male or female, aged 18 years old or older, 2. In good general health as evidenced by medical history 3. Stated willingness to comply with all study procedures and availability for the duration of the study. 4. Ability of subject to understand and the willingness to sign a written informed consent document. HEALTHY VOLUNTEERS-PEDIATRIC 1. Healthy children, male or female, age 7-18, 2. In good general health as evidenced by medical history 3. Stated willingness to comply with all study procedures and availability for the duration of the study 4. Ability of subject or Legally Authorized Representative (LAR)) to understand and the willingness to sign a written informed consent document. SUBJECTS WITH NEUROMUSCULAR DISEASE Adult and pediatric, male or female, patients with a neuromuscular disorder are eligible even if the exact etiology of the disorder is unknown at the time of enrollment into this study. This will include neuropathy, myopathy and motor neuron disorders. It is expected that the subjects are undergoing appropriate standard diagnostic and genetic work-up outside of this protocol that will later clarify the specific etiology of the disorder. Movement disorder will also be included because of the prior research done on dystonia and EIM. Inclusion criteria 1. Suspected motor neuron disease or 2. Suspected myopathy or 3. Suspected neuropathy or 4. Suspected movement disorders that impair intracortical processes 5. Age of 2 years or older 6. Ability of subject to sign a written informed consent document. NIH EMPLOYEES: NIH employees and staff may participate, however EMG Section, OCD, NINDS, employees may not participate. EXCLUSION CRITERIA: HEALTHY VOLUNTEERS-ADULTS 1. Medical conditions that require medications that affects the physiological measures being tested. Some conditions that may be excluded are diabetes, kidney and liver disease. 2. History of stroke, muscle disorders, peripheral neuropathy or spine surgery HEALTHY VOLUNTEERS-PEDIATRIC 1. Medical conditions that require medications that affects the physiological measures being tested. Some conditions that may be excluded are diabetes, kidney and liver disease. 2. History of stroke, muscle disorders, peripheral neuropathy or spine surgery SUBJECTS WITH NEUROMUSCULAR DISEASE: No clinical evidence of a neuromuscular disorder on clinical evaluation.