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Quantitative myotonia assessment with a commercially available dynamometer in myotonic dystrophy types 1 and 2
Author(s) -
Horáková Magda,
Horák Tomáš,
Parmová Olesja,
Bednařík Josef,
Voháňka Stanislav
Publication year - 2019
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.26401
Subject(s) - myotonia , myotonic dystrophy , medicine , muscle relaxation , rating scale , physical medicine and rehabilitation , physical therapy , anesthesia , psychology , developmental psychology
: 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