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Quantitative myotonia assessment with a commercially available dynamometer in myotonic dystrophy types 1 and 2 |
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| Authors: | Magda Horáková MD Tomáš Horák MD Olesja Parmová MD Josef Bednařík MD CSc Stanislav Voháňka MD CSc |
| Affiliation: | 1. Department of Neurology, University Hospital Brno, Jihlavská 20, Brno, 625 00, Czech Republic;2. Department of Neurology, University Hospital Brno, Jihlavská 20, Brno, 625 00, Czech Republic Faculty of Medicine, Masaryk University, Brno, Czech Republic |
| Abstract: | Introduction: The objective of this study was to develop a simple method for quantitative assessment of myotonia in patients with myotonic dystrophy type 1 (DM1) and DM2, to compare the myotonia severity, and to correlate this objective outcome with a subjective scale, the Myotonia Behaviour Scale (MBS). Methods: A commercially available dynamometer was used for all measurements. The relaxation time after voluntary contraction was measured in 20 patients with DM1, 25 patients with DM2, and 35 healthy controls. Results: The average relaxation time was 0.17 s in controls, 2.96 s in patients with DM1, and 0.4 s in patients with DM2. The correlation between relaxation time and MBS score was significant, 0.627 in patients with DM1 and 0.581 in patients with DM2. Discussion: Our method provides a valid and reliable quantitative measure of grip myotonia suitable as an outcome measure in clinical trials and as part of routine examinations to gather data on the natural history of myotonic disorders. Muscle Nerve 59:431–435, 2019 |
| Keywords: | muscle relaxation muscle strength dynamometer myotonia myotonic dystrophy outcome measure warm-up |