Clinical and electrophysiological features in a large cohort of myotonic dystrophy patients
Mailin Oliva1, Miguel Chuquilin Arista1
1University of Florida
To describe clinical and electrophysiological characteristics of patients with myotonic dystrophy type I (DM1) and type II (DM2).



Myotonic dystrophy is characterized by different symptoms including cardiomyopathy, weakness, peripheral neuropathy, and myalgia. We reviewed the disease course of patients with DM1 and DM2 seen at our institution.


Retrospective chart review of DM patients seen at the University of Florida between 1995 and 2017. Clinical and electrophysiological features were analyzed. Chi-Square test was used for statistical analysis.

A total of 166 patients who had DM1 (n=143) or DM2 (n=23) were found. Symptom onset occurred on average earlier in DM1 (28.5 years) than DM2 (52 years). Most patients (n=165) presented with weakness (99.4%), and 80 had myalgia (48.2%). Prevalence of myalgia was significantly different between DM1 (44.8%) and DM2 (69.5%) patients (p=0.026). Neuropathy symptoms (numbness and tingling of the extremities) were more prevalent in DM2 (34.7%) than DM1 (12.6%) (p=0.0065). There was no significant difference in prevalence of sleep (excessive daytime somnolence, poor sleep) or cardiac (angina, palpitations, arrhythmia and/or EKG conduction disturbances) symptoms between DM1 (74.78% for sleep, 55.2% for cardiac) and DM2 (73.9% for sleep and 39.1% for cardiac) (p=0.926 and 0.15 respectively). Pulmonary function testing (n=64 patients) showed a restrictive pattern in 55.2% and 50% of those tested with DM1 and DM2 respectively. Electromyography was performed on 64 patients, and all 16 with DM2 had myotonic discharges compared to 87.5% of 48 with DM1.

Disease onset occurs later and sensory neuropathy symptoms and myalgia are more prevalent in patients with DM2 than DM1. Up to a half of myotonic dystrophy patients can exhibit restrictive pulmonary pattern. This study provides a stronger understanding of the DM disease presentation and course in a large patient population.