EEG-EMG polygraphic study of dystonia and myoclonus in a case of Creutzfeldt-Jakob disease

Abstract

We report on a patient with sporadic Creutzfeldt-Jakob disease (CJD) who showed dystonia, periodic myoclonus, and periodic sharp wave complexes (PSWCs) on EEG. The EEG-EMG polygraphic study revealed that dystonia appeared without relation to periodic myoclonus and PSWCs and that dystonia EMGs were strongly suppressed after periodic myoclonus EMGs. These findings suggest that dystonia has a pathogenesis different from that of periodic myoclonus and PSWCs, but dystonia and periodic myoclonus may be generated through the sensorimotor cortex in CJD.

Keywords: Creutzfeldt–Jakob disease; Dystonia; Myoclonus; Periodic sharp wave complexes.

Fig. 1

Photos of the dystonia. There were two patterns of dystonic posture in the left upper extremity: (A) the shoulder abduction, elbow extension, and grasping, and (B) the shoulder flexion and abduction, elbow flexion, forearm pronation, and wrist flexion. The right upper extremity showed elbow flexion and grasping. DWI-MRI revealed hyperintensities involving the bilateral temporooccipital lobes, caudate heads, and anterior parts of the putamen (C). The hyperintensities were more remarkable on the right side of the brain.

Fig. 2

EEG and EMG polygraphs. (A) Record 1 showed PSWCs on EEGs and synchronized myoclonus on EMGs. (B) Record 2 showed PSWCs, but no myoclonus. (C) Record 3 showed PSWCs and dystonia of the left upper extremity. (D) Record 4 showed dystonia without PSWCs in the initial recording part and dystonia and concomitant myoclonus with PSWCs in the later part. In Record 4, the positive myoclonus was superimposed on dystonia, and the dystonic contractions were strongly suppressed in the periods following the positive myoclonus.