Subtle cognitive dysfunction in adult onset myotonic dystrophy type 1 (DM1) and type 2 (DM2).

The authors performed neuropsychological testing in 21 patients with myotonic dystrophy type 1 (DM1) and 21 with type 2 (DM2) and healthy controls. They detected no general cognitive deficit in either DM1 or DM2, but compared to controls, both groups of patients were inferior in tests of prefrontal functioning. Patient groups did not differ in any measure. Mood status was not related to neuropsychological performance. This is consistent with findings of executive dysfunction in both DM1 and DM2.