High frequency bursting during rapid finger movements in an unusual case of epilepsia partialis continua

Myoclonic activity was analyzed in a 25-year-old male patient suffering from epilepsia partialis continua in his right finger and hand extensors and flexors. The involuntary tremorlike regular muscle jerks occurred at an average rate 7.7/s under resting conditions. Bursting frequency did not change during smooth ramp movements but increased up to 25/s during rapid extensions of the fingers. The EEG showed trains of sharp waves over the left temporoparietal and the midcentral regions but backaveraging did not yield reproducible jerk-related potentials. Somatosensory evoked potentials were not enhanced. It is suggested that the observed pattern of muscle jerks resulted from a spontaneous bursting behaviour of motor cortical neurones.