FOCAL ACTION MYOCLONUS DUE TO LOCALIZED H EMISPHERIC LESION - A POLYGRAPHIC AND PHARMACOLOGICAL STUDY

Authors report a case of focal action myoclonus due to a localized hem ispheric lesion. The woman had cardiac arrest complicated by ischemic stroke involving the left parietal region. Action myoclonus of the inf erior right limb was the sole residual complaint, provoked by movement and maintenance of posture. Patient noted that myoclonus was worsened by carbamazepine and vigabatrin. EEG-EMG polygraphic study demonstrat ed action myoclonus and showed a particular EEG activity consisting in a volley of spikes on the vertex region during the right inferior lim b movements. Contralateral movements did not elicit this activity. Pha rmacological response to clonazepam, piracetam and alcohol was studied . A marked improvement of myoclonus was obtained with alcohol. Pathoph ysiology of this exceptional form of cortical action myoclonus is disc ussed.