Journal article
Prospective Study of Video Hand Opening Time as a Quantitative Measurement of Myotonia in Patients With Myotonic Dystrophy Type 1
Neurology, Vol.106(7), e214747
04/14/2026
DOI: 10.1212/WNL.0000000000214747
PMID: 41747205
Abstract
Delayed grip relaxation is a common symptom of myotonic dystrophy type 1 (DM1), differing from other muscle diseases. Preclinical studies suggest myotonia may reverse quickly with targeted treatment and video hand opening time (vHOT) could be a straightforward method for assessing myotonia in multicenter trials, but few studies have evaluated vHOT in large DM1 cohorts. This study aimed to evaluate how vHOT performs and relates to other disease aspects in a large, well-characterized DM1 population.
The vHOT was conducted in the END-DM1 natural history study across 22 international sites, including adult DM1 patients with a genetic or research criteria diagnosis. The primary outcome involved video-recorded hand opening after a maximum 3-second grip, performed twice at each study visit with 5-minute rest between trials, and blinded scoring at a central site. Muscle strength and function were assessed by myometry, timed functional tests, and patient-reported outcomes. Procedures were repeated after 1 year for a subset of participants. Wilcoxon signed-rank was used to evaluate differences and Spearman correlation for associations.
A total of 591 patients with DM1 (mean age 43.7 ± 12.9 years, 57% female) were included, showing a broad spectrum of vHOT severity (median 3.9 seconds, interquartile range 1.8-7.9 seconds). At a single study visit, there were no systematic difference and good agreement between trials (mean difference 0.1 ± 3.7 seconds [
= 0.05], intraclass correlation coefficient 0.84 [95% CI 0.81-0.86]). vHOT correlated relatively weak with self-reported myotonia (ρ = 0.39), and even lower for other measures of muscle impairments such as grip strength (ρ = -0.21) or 9-hole pegboard (ρ = 0.12). 270 patients completed the 1-year follow-up, with vHOT showing no progression (mean difference 0.4 ± 4.7 seconds,
= 0.34).
The vHOT procedure was performed successfully in a large international study, with grip relaxation delay varying from minimal to highly prolonged in an unselected cohort. The weak correlation with grip weakness supports the notion that myotonia and weakness are mechanistically distinct. Study limitations include underrepresentation of congenital DM1 and lack of other myotonia measures (e.g., handgrip relaxation myometry). It seems that vHOT is not suitable to assess disease progression, but stability over 1 year may support its use to assess improvement.
The END-DM1 observational study is registered with number NCT03981575.
Details
- Title: Subtitle
- Prospective Study of Video Hand Opening Time as a Quantitative Measurement of Myotonia in Patients With Myotonic Dystrophy Type 1
- Creators
- Kristofoor E Leeuwenberg - Radboud University NijmegenValeria A Sansone - Centro Clinico NemoJohanna Hamel - University of Rochester Medical CenterMan Hung - Virginia Commonwealth UniversityJeanne M Dekdebrun - University of Rochester Medical CenterAndrea Lizio - Centro Clinico NemoKaty Eichinger - University of Rochester Medical CenterCynthia Gagnon - Centre Intégré Universitaire de Santé et de Services Sociaux du Saguenay–Lac-Saint-JeanRichard H Roxburgh - University of AucklandSub H Subramony - Florida CollegeJeffrey M Statland - University of Kansas Medical CenterBakri H Elsheikh - The Ohio State University Wexner Medical CenterChris Turner - University College LondonEmma L Matthews - St George’s University Hospitals NHS Foundation TrustThomas E Ragole - University of Colorado Anschutz Medical CampusJacinda B Sampson - Stanford UniversityBenedikt Schoser - Ludwig-Maximilians-Universität MünchenMasanori P Takahashi - The University of OsakaMatthew P Wicklund - The University of Texas Health Science Center at San AntonioAndrea J Swenson - University of IowaChamindra G Laverty - University of California San DiegoPerry B Shieh - University of California, Los AngelesEricka P Greene - Houston MethodistJennifer Raymond - Virginia Commonwealth UniversityErin DeSpain - Virginia Commonwealth UniversityCharles A Thornton - University of Rochester Medical CenterKarlien Mul - Radboud University Medical CenterNicholas E Johnson - Virginia Commonwealth UniversityMyotonic Dystrophy Clinical Research Network
- Resource Type
- Journal article
- Publication Details
- Neurology, Vol.106(7), e214747
- DOI
- 10.1212/WNL.0000000000214747
- PMID
- 41747205
- NLM abbreviation
- Neurology
- ISSN
- 1526-632X
- eISSN
- 1526-632X
- Publisher
- American Academy of Neurology
- Grant note
- US Food and Drug Administration (FDA)Wyck Foundation/Myotonic Dystrophy FoundationTakeda Development Center Americas, Inc.SanofiPfizerFDAFDA Public Access Policy
The END-DM1 study is funded by the US Food and Drug Administration (FDA), Wyck Foundation/Myotonic Dystrophy Foundation, Avidity Biosciences, Dyne Therapeutics, Vertex Therapeutics, Takeda Development Center Americas, Inc., PepGen, Sanofi, and Pfizer. This work was supported by the FDA under award number FD-R-006071. This manuscript is the result of funding in part by the FDA. It is subject to the FDA Public Access Policy. Through acceptance of this federal funding, FDA has been given a right to make this manuscript publicly available in PubMed Central upon the Official Date of Publication, as defined by FDA.
- Language
- English
- Date published
- 04/14/2026
- Academic Unit
- Neurology
- Record Identifier
- 9985139270102771
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