Quantitative myotonia assessment with a commercially available dynamometer in myotonic dystrophy types 1 and 2

Horáková, Magda; Horák, Tomáš; Parmová, Olesja; Bednařík, Josef; Voháňka, Stanislav

doi:10.1002/mus.26401

Cited by 5 publications

(2 citation statements)

References 12 publications

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“…The MBS scale was developed for patients with myotonia congenita, who mostly show a severer grip myotonia in comparison to DM2 (22). In a recently published study, MBS has been adopted also in DM1 and DM2 patients to validate the relaxation time on a dynamometer as measurement of myotonia (23). The results of our study were similar to those recently published by Horakova et al as we found a mean MBS score of 1.5 (vs. Horakova 1.6).…”

Section: Discussionsupporting

confidence: 89%

Validation of Motor Outcome Measures in Myotonic Dystrophy Type 2

Montagnese¹,

Rastelli²,

Khizanishvili³

et al. 2020

Front. Neurol.

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Introduction: Myotonic dystrophy type 2 (DM2) lacks disease-specific, validated, motor outcome measures (OMs), and patients' reported outcomes (PROs). This represents a limit for the monitoring of disease progression and treatment response. Our aim was to identify the most appropriate OMs to be translated in clinical practice and clinical trials on DM2. This study has been registered on clinicaltrials.gov NCT03603171 (https:// clinicaltrials.gov/ct2/show/NCT03603171).Methods: Sixty-six patients with genetically confirmed DM2 underwent a baseline and a follow-up visit after 1 year. The tested OMs included: hand opening time, pressure pain threshold (PPT), manual muscle testing (MMT), hand held dynamometry (HHD), scale for the assessment and rating of ataxia (SARA), quantitative motor function test (QMFT), gait stairs Gowers chair (GSGC), 30-s sit to stand test, functional index 2 (FI-2) and 6MWT. The PROs included DM1-Active-C, Rasch-built Pompe-specific activity scale (R-Pact), fatigue and daytime sleepiness (FDSS), brief pain inventory short form (BPI-sf), myotonia behavior scale (MBS), and the McGill pain questionnaire.Results: All patients completed the MBS and the results correlated well with the handopening time. The PPT showed a low reliability, no correlation with pain questionnaires, and did not differentiate patients with or without myalgia. Both muscle strength assessments, MMT and HHD, showed good construct validity. The QMFT showed an acceptable ceiling effect (14.5%), good convergent and differential validity and performed overall better than GSGC. The SARA score showed high flooring effect and is not useful in DM2. 6MWT proved a valid outcome measure in DM2. The 30-s sit to stand is a feasible test with good convergent validity, showing a flooring effect of 20% as it cannot be used in more severely affected patients. The FI-2 is time-consuming and has a high ceiling effect. At the 1-year visit the only assessments able to detect a worsening of DM2 were HHD, QMFT, and 6MWT, which are the most sensitive to change, and therefore clinically meaningful OMs in DM2. Conclusion:The clinical meaningful motor outcome measures that best depict the multifaceted phenotype of DM2 and its slow progression are MBS, MMT, or HHD (depending on the clinical setting), QMFT, and the 6MWT.

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Section: Discussionsupporting

confidence: 89%

Validation of Motor Outcome Measures in Myotonic Dystrophy Type 2

Montagnese¹,

Rastelli²,

Khizanishvili³

et al. 2020

Front. Neurol.

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“…The software is commercially licensed, specific to the force transducer and does not allow modifications to include other measures for example, audio commands. Other approaches using dynamometry or a sensor glove either showed poor repeatability or did not measure grip force time series and the warm-up typical of myotonia [13][14][15] .…”

Section: Introductionmentioning

confidence: 99%

Simple and economical HandClench Relaxometer device for reliable and sensitive measurement of grip myotonia in myotonic dystrophy

Bulea

Gúth

Sarkar

et al. 2022

Neuromuscular Disorders

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Tissue Doppler ultrasound of arm muscles to assess myotonia in myotonic dystrophies: An exploratory study

Svačina,

Sprenger‐Svačina,

Kohle

et al. 2024

Muscle and Nerve

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Introduction/AimsMyotonia is a key symptom of myotonic dystrophies (DM), and its quantification is challenging. This exploratory study evaluated the utility of tissue Doppler ultrasound (TDU) to assess myotonia in DM.MethodsTwelve DM patients (seven type‐1 DM [DM1] and five type‐2 DM [DM2]) and 20 age‐matched healthy subjects were included in this cross‐sectional study. After measuring cross‐sectional areas of the flexor digitorum superficialis (FDS) and extensor digitorum communis (EDC) muscles in a resting state, muscle contraction/relaxation time, time to peak tissue velocity, peak tissue velocity and velocity gradients of these muscles were measured via TDU while performing forced fist unclenching after fist closure. Additionally, grip strength, Medical Research Council Sum score and patient‐reported myotonia severity scores were assessed.ResultsDM1 and DM2 patients had a lower grip strength than healthy subjects (p = .0001/p = .002). Patient‐reported myotonia did not differ between DM1 and DM2 patients. DM1 patients revealed FDS and EDC atrophy compared to DM2 patients and healthy subjects (p = .003/p = .004). TDU revealed prolonged muscle contraction and relaxation times in both DM subtypes, with prolonged time to reach FDS peak relaxation velocity and altered peak FDS relaxation velocity only in DM1 patients (p = .03/p = .003). Peak FDS relaxation velocity correlated inversely with C(C)TG repeat numbers in DM patients. Sensitivity of TDU parameters to detect myotonic dystrophy varied between 50% and 75%, with a specificity of 95%.DiscussionOur exploratory study suggests that TDU could serve as a novel tool to quantify myotonia in DM patients, but larger follow‐up studies are warranted to validate its diagnostic accuracy.

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Quantitative myotonia assessment with a commercially available dynamometer in myotonic dystrophy types 1 and 2

Cited by 5 publications

References 12 publications

Validation of Motor Outcome Measures in Myotonic Dystrophy Type 2

Validation of Motor Outcome Measures in Myotonic Dystrophy Type 2

Simple and economical HandClench Relaxometer device for reliable and sensitive measurement of grip myotonia in myotonic dystrophy

Tissue Doppler ultrasound of arm muscles to assess myotonia in myotonic dystrophies: An exploratory study

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