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12: Needle Electromyography

DOI:

10.1891/9781617050053.0012

Abstract

Clinical electromyography (EMG) refers to nerve conduction studies and needle electromyography (NEMG) examination. The NEMG examination can be a stressful situation for the patient and for the electromyographer as well. The NEMG starts with proper identification of the muscle to be examined. During NEMG, the process of muscle identification involves correlating the burst of motor unit action potentials (MUAPs) with the voluntary contraction of the appropriate muscle using a combination of visual and auditory analysis. The patients may report severe discomfort when the NEMG is within the end plate zone. Fibrillation Potentials (FPs) are most commonly seen in denervated muscles associated with nerve or motor neuron dysfunction. Myokymia, characterized by wormlike movements of the skin, can be recorded with the NEMG electrode. Myotonic discharge is the electrical counterpart of myotonia.