Orofacial strength, dysarthria, and dysphagia in congenital myotonic dystrophy.

INTRODUCTION: Herein we present an exploratory study of orofacial function in children with congenital myotonic dystrophy (CDM) vs. healthy controls. METHODS: We evaluated 41 children with CDM and 29 healthy controls for speech and swallow function and for lingual and labial strength. RESULTS: The Iowa Oral Performance Instrument (IOPI), measuring tongue strength, and a lip force meter (LFM), measuring lip strength, had excellent interrater reliability with intraclass correlation coefficients (ICCs) of 0.75 (n = 19, P < 0.001) and 0.96 (n = 20, P < 0.001), respectively. Mean overall lingual strength was 3.5-fold less and labial strength was about 7-fold less in CDM patients than in healthy controls. Eighteen of 24 children with CDM demonstrated dysarthria and an additional 11 participants were nonverbal. Dysarthria correlated moderately with lingual strength, age, and dysphagia. Strength measures correlated moderately with dysphagia. DISCUSSION: Children with CDM have impaired orofacial functioning that affects communication and swallowing. Reliability of strength measures may be useful for future therapeutic trials. Muscle Nerve 58: 413-417, 2018.

Physical function and mobility in children with congenital myotonic dystrophy.

INTRODUCTION: Congenital myotonic dystrophy (CDM) occurs when symptoms of myotonic dystrophy present at birth. In this study we evaluated the relationship between physical function, muscle mass, and age to provide an assessment of the disease and help prepare for therapeutic trials. METHODS: CDM participants performed timed functional tests (TFTs), the first 2 minutes of 6-minute walk tests (2/6MWTs), and myometry tests, and also performed dual-energy X-ray absorption (DEXA) scans. Healthy controls (HCs) performed TFTs, 6MWTs, and myometry. RESULTS: Thirty-seven children with CDM and 27 HCs (age range 3-13 years) participated in the study. There were significant differences in the 10-meter walk (11.3 seconds in CDM vs. 6.8 seconds in HC) and 2MWT (91 meters in CDM vs. 193 meters in HCs). DEXA lean mass of the right arm correlated with grip strength (r = 0.91), and lean mass of the right leg correlated with 6MWT (r = 0.62). CONCLUSION: Children with CDM have significant limitations in strength and mobility. The tests performed were reliable, and lean muscle mass may serve as a useful biomarker. Muscle Nerve 56: 224-229, 2017.