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Types of Electromyographic Abnormalities 

Types of Electromyographic Abnormalities
Types of Electromyographic Abnormalities

Jun Kimura

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date: 28 November 2021

This chapter describes types of electromyographic abnormalities, which include decreased and prolonged insertional activities, insertional positive waves, myotonic discharges, and spontaneous activities such as fibrillation potentials, positive sharp waves, complex repetitive discharges, fasciculation potentials, and myokymic and neuromyotonic discharges. The four steps of electromyography help categorize motor dysfunction into upper and lower motoneuron disorders and myogenic lesions. Isolated discharges of single motor axons induced by voluntary effort give rise to motor unit potentials. Diseases of the nerve or muscle cause structural or functional disturbances of the motor unit, which in turn lead to alterations in the waveform and discharge patterns of their electrical signals. Certain characteristics of such abnormalities suggest a particular pathologic process, providing information useful in elucidating the nature of the disease.

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