Gagnon C, et al. - Experts attempted to document muscle strength changes in eight muscle groups among adults with myotonic dystrophy type 1 (DM1) over a 9-year period as well as to compare this progression between phenotypes (adult and late-onset) and sex. They recruited patients with a genetic diagnosis of DM1 with the late-onset or the adult phenotype at baseline through the clinical registry of the Saguenay Neuromuscular Clinic. As compared to women, men were stronger and showed a significantly greater rate of decline of muscle strength. In addition, the adult and late-onset phenotypes taken separately displayed a significant and similar decline over the 9-year period, except for the wrist and knee extensors where muscle strength of participants with the adult phenotype decreased faster than in the late-onset phenotype. They reported that the similar rate of decline of muscle strength loss seen between phenotypes highlights the need to develop interventions to prevent this decline, even for patients with the late-onset phenotype who were often considered as mildly impaired, and therefore neglected by the rehabilitation services.