The origin of spontaneous discharges in acquired neuromyotonia. A Macro EMG study. |
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| Authors: | Kimiyoshi Arimura Yumiko Arimura Arlene Ng Akiko Uehara Megumi Nakae Mitsuhiro Osame Erik St?lberg |
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| Institution: | Department of Neurology and Geriatrics, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, 8-35-1 Kagoshima, Japan. ari@m2.kufm.kagoshima-u.ac.jp |
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| Abstract: | OBJECTIVE: To study the generator sites of spontaneous discharges in patients with immune-mediated neuromyotonia. METHODS: Macro EMGs triggered by both spontaneously and voluntarily activated single action potentials were recorded and the mean peak-to-peak amplitude and area of the macro motor unit potentials were compared in two patients with typical acquired neuromyotonia having positive antibodies against voltage-gated potassium channels. RESULTS: Mean peak-to-peak amplitude and area of Macro EMG motor unit potentials (macro MUPs) triggered by spontaneous discharges were significantly smaller than those triggered by voluntary activation in both patients. However, a few macro MUPs triggered by spontaneous discharges resembled those triggered by voluntary activation. CONCLUSIONS: Spontaneous discharges in two patients with immune-mediated neuromyotonia seem to be mostly generated at sites distal to the terminal axon branching points. SIGNIFICANCE: This finding may provide a new insight in the understanding of spontaneous discharges in immune-mediated neuromyotonia. |
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