Neuromuscular transmission abnormalities in myotonic dystrophy type 1: A neurophysiological study

Objectives: Weakness and fatigue are frequent symptoms in myotonic dystrophy type 1 (DM1), mainly as a result of muscle impairment. However, neuromuscular junction (NMJ) abnormalities could play an additional role in determining these manifestations. We aimed to document the possible NMJ involvement in DM1. Patients and methods: In order to substantiate this hypothesis we performed low rate repetitive nerve stimulation (RNS) and single fiber electromyography (SFEMG), in 14 DM1 subjects. Results: RNS resulted abnormal in four patients while SFEMG revealed a pathological jitter in ten. A significative correlation was found between jitter values and decrementing response (p < 0.000311; r= 0.822). Conclusion: These results suggest a possible involvement of NMJ in DM1. (C) 2016 Elsevier B.V. All rights reserved.