Background: \- Electrical impedance myography (EIM) is a new technique being studied to see if it is helpful in evaluating muscle disorders and nerve disorders. EIM looks at how a mild, painless electrical current travels through muscles. Researchers want to gain experience in using the EIM device. They will collect information on the results of using it on people with and without nerve and muscle diseases, and compare that with information from other standard tests. First, they will test the device on healthy people. Then they will test people with a variety of neuromuscular diseases. Because the test is noninvasive and not painful, researchers will test both children and adults. Objectives: \- To gain experience using the EIM muscle testing device. Eligibility: * Healthy volunteers at least 2 years old. * Individuals at least 2 years old who have neuromuscular disease. Design: * Participants will be screened with a medical history and physical exam. * Participants will have one 2-3 hour clinic visit. Researchers may request follow-up visits. * Participants will be tested with the EIM device. The device and small electrodes will be placed on their skin. An electric current will pass through the device, but the participants will not feel this. * Participants may have an ultrasound test. A gel will be put on their skin, and a device will be moved over the skin. * Participants may have a nerve test. Electrodes will be placed on their skin, and they will feel a small shock. * Participants may have a test where a thin needle is inserted in their muscle.
Study Description: This is a natural history study examining the utility of electrical impedance myography (EIM) device in the evaluation of neuromuscular disorders. This is a novel device so the initial step was to establish reproducibility of the data and expected normative values using the EIM device on healthy volunteers. In neuromuscular disorders, the EIM device will be used to understand the results in different types of neuromuscular disorders. A subset of subjects with neuromuscular disorders are studied serially as preliminary evaluation of its utility as a biomarker in clinical studies. The protocol includes both adult and pediatric subjects. Objectives: Primary objective: For subjects with neuromuscular disease, we aim to understand if EIM has utility in differentiating neuromuscular disorders in adult and pediatric subjects. Also, to perform preliminary serial studies to understand the EIM device potential use as biomarker in clinical studies. For healthy volunteers, the primary objective is reproducibility of results and the range of normative values in adult and pediatric subjects. Secondary objectives: The three parameters, phase, reactance, resistance will be followed serially as measures of change in pediatric population. As exploratory outcome measures, we will explore correlations between EIM and ultrasound and other electrodiagnostic methods. Endpoints: Primary endpoint: For healthy volunteers, intra and interrater reliability will be evaluated to determine the utility of EIM as a reproducible biomarker. Normative values will be developed using a range of ages, mixed gender, and race to be used as a basis of comparison with subjects with neuromuscular disorders. For subjects with neuromuscular disorders, patterns of phase, resistance and reactance in different types of neuromuscular disorders will be evaluated and examined for patterns specific to type of neuromuscular disorder. Secondary endpoint: The three parameters, phase, reactance, resistance will be followed serially as measures of change. This will be evaluated in small groups of neuromuscular disorders that are referred to this protocol. A cohort of pediatric healthy volunteers will be followed for two years for comparative data with pediatric subjects with neuromuscular disorders. Exploratory endpoint: The EIM phase, muscle ultrasound and possibly MUNIX will be compared in healthy volunteers.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
275
EIM device is placed on the muscle and a high frequency current is delivered to the skin.
Ultrasound waves to examine the muscles and nerves
Small metal disk electrodes attached to wires onto skin to measure how fast nerves conduct electrical impulses and the strength of the connection between nerves and muscles.
Thin needle placed into muscles to record electrical activity-adults only
National Institutes of Health Clinical Center
Bethesda, Maryland, United States
RECRUITINGPatients - EIM measures for a selection of muscles
Obtaining measures using EIM device in different types of neuromuscular disorders.
Time frame: End of study
Healthy Volunteers - EIM measures for a selection of muscles with the aim of developing normative values for the NIH EMG lab
Obtaining measures using EIM device- reproducibility and normative data
Time frame: End of study
Serial studies in pediatric patients
Serial measures of EIM in patients with neuromuscular disorders
Time frame: End of study
Healthy Volunteers - exploratory correlations of ultrasound and electrodiagnostic methods such nerve conduction studies and less likely, EMG
Obtaining measures using EIM device and comparing with ultrasound and motor unit number estimation techniques.
Time frame: End of study
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