Observational Study of Digital Biomarkers of Myotonia and Gait in Adults and Children With Myotonic Dystrophy

Inclusion Criteria: * Ability to provide informed consent * Age 12-90 years old at the time of informed consent * Genetic confirmation of DM1 or DM2 * Ability to comply with study assessments * Clinically apparent myotonia equivalent to hand opening time of at least 2 seconds, in the opinion of the Investigator * Ambulatory (orthoses allowed, canes and walkers not allowed) and able to walk at least 25 meters at screening Exclusion Criteria: * Ongoing medical condition (e.g. wasting or cachexia, severe anemia) that would, in the opinion of the Investigator, interfere with the conduct or assessments of the study * Significant cognitive impairment, clinical dementia, or unstable psychiatric illness, including psychosis, suicidal ideation, suicide attempt, or untreated major depression ≤ 90 days of screening, which in the opinion of the Investigator may interfere with the study procedures * Treatment with an investigational drug, biologic agent, or device within one month of screening, or 5 half-lives of investigational agent, whichever is longer * Inability to comply with study requirements * Other unspecified reasons that, in the opinion of the Investigator or the Sponsor, make the participant unsuitable for enrolment