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. 2020 Mar;61(3):387-390.
doi: 10.1002/mus.26789. Epub 2020 Jan 6.

Spontaneous continuous motor unit single discharges

Andreas Posa  1 , Izabela Niśkiewicz  1 , Valerian Raescu  1 , Alexander Emmer  1 , Alexey Surov  2 , Malte Kornhuber  1   3
Affiliations

Spontaneous continuous motor unit single discharges

Andreas Posa et al. Muscle Nerve. 2020 Mar.

Abstract

Introduction: Motor unit hyperexcitability (MUH) may become manifest in needle electromyography (EMG) recordings as fasciculation potentials, myokymic discharges, or neuromyotonic discharges. Here, we describe a further MUH phenomenon.

Methods: Needle EMG recordings of the Neurology Hospital of Halle (Saale) stored in a video mode as .wav data between 2000 and 2015 were screened for spontaneous continuous motor unit single discharges (SCMUSD).

Results: We identified 23 video needle EMG waveforms from 14 patients with SCMUSD. The corresponding motor units discharged at a rate of about 6 H Z (6.3 ± 4.0; range, 1.3-18.1). The coefficient of variation of the discharge rate was 3.5% ± 1.7%. Neurogenic disorders were diagnosed in 12 patients, limb girdle muscle dystrophy was diagnosed in one patient, and stiff-limb syndrome was diagnosed in one patient.

Discussion: Spontaneous continuous motor unit single discharge, as described here, widens the spectrum of MUH phenomena.

Keywords: axonal sprouting; jitter; motor unit hyperexcitability; needle electromyography; neuromyotonia; spontaneous activity.

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References

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