Cognitive event-related potentials and magnetic resonance imaging in myotonic dystrophy

Fourteen patients with myotonic dystrophy (MyD) were studied with means of an auditory "oddball" event-related potential (ERP) paradigm. The results were compared with data from 53 controls. The early components (N1, P2) of the ERP were not affected, whereas later components (N2, P3), which are thought to reflect cognitive processes, were abnormal in eight patients who were the oldest in the sample. Magnetic resonance imaging (MRI) was performed in twelve patients and revealed, in five of them, multiple focal white matter lesions. These findings, however, could not be associated with neurophysiological abnormalities. It is concluded, that cognitive ERP, particularly N2 and P3 components, are abnormal in some patients suffering from MyD. Possible etiologies of the electrophysiological abnormalities are discussed.