Cortical thinning and white matter alterations in myotonic dystrophy type 2 over a 10-year period

Cortical thinning and microstructural white matter alterations have been shown to occur in myotonic dystrophy type 2 (DM2). So far, longitudinal investigations are scarce and no significant differences of changes over 5 years were found between patients and healthy controls (HC). We hypothesized that DM2 might develop stronger brain alterations after long time periods of 10 years and that cortical thickness might be a representative biomarker for tracking cerebral changes in DM2.

Ten DM2 patients and seven HC were included in this study who received two brain MRI examinations over 10 years. Brain images were segmented to obtain cortical thickness (CT) by use of CAT12. CT alterations were investigated with surface-based morphometry in CAT12. Diffusion tensor imaging data were pre-processed using MRtrix and fractional anisotropy (FA) maps were obtained by FSL's dtifit, which were analyzed with tract-based-spatial statistics.

CT was significantly reduced over time in several brain areas in DM2 patients, but in only few regions in HC. DM2 patients showed decreased FA values in different brain regions, and larger differences from baseline to follow-up were obtained for DM2 patients than for HC.

In this longitudinal study, distinct local patterns of cortical thinning and microstructural white matter alterations in DM2 over a 10-year period could be identified. These might serve as biomarkers for tracking long-term brain changes in DM2.