2. Spontaneous activity in electromyography – Generators and clinical correlations

Abstract

In this paper different types of spontaneous activity in electromyography are presented. Possible generators of certain types of spontaneous activity (fibrillations, positive denervation potentials, fasciculations, diplets, triplets, multiplets, myokymic discharges, complex repetitive discharges, myotonic discharges, neuromyotonic discharges, cramps) across different parts of the motor units (MU) and clinical entities and syndromes in which it may be registered. There is no unique explanation for the generators of certain types of spontaneous activity in some entities. Thus, the registration of fasciculations in ALS is associated with their multifocal origin along various parts of MU. Recording of spontaneous activity may have diagnostic and prognostic value in certain neuromuscular disorders. Thus, the expression of fibrillations (1+ to 4+) is associated with the number of denervated muscle fibers in different diseases and damage of various parts of MU (motor neuron disease, neuropathy, disorders of the neuromuscular junction, myopathies). We analyzed the possible significance of various parameters of spontaneous activity in the diagnosis and prognosis of certain entities.