Theory of Mind in Myotonic Dystrophy Type 1 Is Associated With Cortical Gyrification and White Matter...

Theory of Mind (ToM) Refers to the ability to infer other people's thoughts (Cognitive ToM) and emotions (Affective ToM). Myotonic Dystrophy Type 1 (DM1) Patients Showed an impairment of ToM capacities, but the underlying neural mechanisms remain poorly understood.

We included 58 adult non-congenital DM1 patients from the DMVASCOG cohort, who underwent a ToM evaluation using the Movie for the Assessment of Social Cognition and a brain MRI. Association of ToM scores with cortical thickness and gyrification was assessed using FreeSurfer software, and associations with white matter hyperintensities were assessed using SVR-LSM. Finally, we included all the significantly associated parameters in a multivariate model.

The ToM total score and cognitive subscore were both associated with the local gyrification in the right superior parietal gyrus and with the hyperintensities in the bilateral temporopolar white matter. The ToM total score was also associated with hyperintensities in the bilateral temporo-parietal and left frontal white matter. Multivariate models based on these parameters allowed a better prediction of the ToM total score (R² = 0.49) and cognitive subscore (R² = 0.52) than univariate models. There was no association between ToM measures and cortical thickness, nor between brain MRI measures and affective subscore/error types.

The ToM cognitive involvement in DM1 is associated with both the gyrification in the right superior parietal gyrus and the volume of hyperintensities in the anterior-temporal white matter, suggesting the possible joint implication of a neurodevelopmental phenomenon and disconnections arising from white matter changes.