Understanding Hyper Motor Seizures

Introduction: Hyper Motor Seizures [HMS] are characterized by complex high amplitude movements involving proximal segments of the body resulting violent and inappropriate to the context. Objective: To review the possible ictal onset zones related to HMS and the cortical areas that would be covered if invasive recording are needed. Development: Semiology can predict the localization of ictal onset zone. Two subtypes of HMS [type 1 and 2] have been described. HMS1 is associated with an epileptogenic zone on the ventromedial frontal cortex and HMS2 has been associated with a more dorsal epileptogenic zone than those resulting in HSM1. However, HMS can also be originated in temporal lobe [mesial, neocortical or in the pole], in insular cortex or even in parietal lobe. The origin of HMS can be suspected by the associated signs. Thus, HMS originating in the insula–operculum regions can be associated with various somatosensory auras; in parietal seizures, propioceptive sensations may precede hyper motor behavior [HM], whereas autonomic and emotional auras prompt to think in the temporal lobe origin. Conclusion: Except in cases of lesional temporal lobe epilepsy with concordant prersurgical results, all patients with HMS should be evaluated through intracranial recordings. The auras, the HMS subtype, the hypometabolic areas showed by PET study, and the localization and lesion type seeing on MRI can help to decide what structures should be covered with depth electrodes during invasive recordings.