INVESTIGATIONS ON A PATIENT SUBJECT TO MYOCLONIC SEIZURES AFTER SENSORY STIMULATION

THE discharges which occur in the electroencephalogram (EEG) during myoclonic seizures have been described by Grinker, Serota, and Stein (1938), by Gibbs and Gibbs (1941), and by Jasper (1941a). None of these workers reported any effects of sensory stimulation on -the course of the seizures or on the characters of the disturbances in the EEG. Two patients have been described (Dawson, 1946) in whom sensory stimulation under favourable conditions would provoke a myoclonic seizure. During the seizure which followed a stimulus such as a tap on a tendon, the discharges in the EEG seemied to be larger on the side of the head opposite to the limb stimulated. The evidence that this difference in the size of the discharge on the two sides.of the head was related to the side of the body Stimulated was not considered to be satisfactory. The' purpose of this paper is to describe experiments carried out on a single subject inwhom sensory stimuli provoke myoclonic seizures. These seizures are, preceded by electrical disturbances which are ,'detectable on the scalp and whose characters suggest that they are of cerebral origin. The disturbances appear largest on the side opposite to that stimulated; they appear near to the midline when the -stimulus is applied to a leg and more laterally when itis applied to an arm. Studies have been made of the characters of these discharges and of the afferent systems, concerned in their production.