Multimodal evoked potentials, EEG and electroretinography in patients with dystrophia myotonica.

EEG, somatosensory (SEP) and visual evoked potentials (VEP) and electroretinography (ERG) were recorded from 16 patients with clinical and electromyographically verified dystrophia myotonica. The results were compared to an age- and sex- matched control group and revealed statistically significant differences between the group mean values for almost all records. Furthermore, abnormal individual electrophysiological tests were relatively frequent in the patient group. No correlation was found between abnormalities in one test compared to abnormalities in the other tests. Furthermore, no correlation was found between the number of electrophysiological abnormalities and the frequency of the disease in the nearest family. The number of abnormal electrophysiological tests increased, however, with age of the patients and duration of the disease.