EEG observations in dystrophia myotonica (Curschmann-Steinert).

An investigation has been carried out in a group of 84 (+2) patients suffering from myotonic dystrophia (Curschmann-Steinert). Manual measurements show that in these patients: (1) the alpha rhythms have low frequencies, related to the age of the patient and to the duration and severity of the disease; (2) the alpha rhythms are regular, monotonous; (3) the alpha rhythms have small amplitudes; there appears to be no relation between alpha frequency and amplitude; (4) the alpha indices are high during eyes closed as well as during eyes open. The computer measurements generally appear to concur with the above and in addition show that the bilateral and longitudinal coherences are high, indicating considerable synchrony of the alpha rhythm over large areas on both sides of the head. The possible significance of these observations is discussed.