S49. Repetitive nerve stimulation in myotonic dystrophy type I

Abstract

Analysis of repetitive nerve stimulation in myotonic dystrophy type I (DM1). Retrospective analysis of DM1 patients in Peking Union Medical College Hospital from January 2015 to October 2016. The clinical data including age of onset, course of disease, family history, symptoms and signs, other system performance, peripheral nerve physiological data includes the upper and lower limbs Motor Conduction Velocity Sensory Conduction Velocity, muscle needle Electromyography and low frequency and high frequency repetitive nerve stimulation; gene information including CTG repeat sequence number. A total of 12 cases were collected, including 11 males and 1 females. The age of onset was 12 years and 54 years old. The course of disease was 2–20 years. All the patients had myotonic phenomenon, not easy to relax hands after hanging on. CTG repeats were detected in all cases, >50 times in 7 cases, and >100 in 5 cases. All patients underwent repetitive nerve stimulation, and no amplitude reduction was found in low frequency stimulation. High frequency stimulation showed that 5 cases of amplitude decreased >30%, 2 cases decreased 20–30%, and 5 cases showed no amplitude decrease. A decrease in amplitude of high frequency repetitive nerve stimulation found in DM1, suggesting that there may be a neuromuscular junction disorder in myotonic dystrophy.