Epilepsies and Mirror Movements: An Underrecognized Association?

Mirror movements (MMs) are related to structural alterations of the pyramidal tract or transcallosal pathways, as well as functional impairment of the interhemispheric inhibitory effects on motor planning skills, leading to the inability to perform limb movements independently. On the other hand, white matter bundles that connect distant cortical regions are thought to be the anatomical substrate of seizure propagation in epileptic subjects, and the spread of excitation through intracortical and transcallosal pathways is a well-recognized pathophysiological abnormality in epilepsies. To investigate this possible association, we searched the MEDLINE and Embase electronic databases, and only original articles were considered eligible for inclusion; we found thirteen patients from eleven articles, all of them case study reports. Therefore, epilepsy and MM co-morbidity has rarely been reported in the same subjects, even if changes in interhemispheric modulation are shared by both conditions. However, the study of this co-morbidity may help in elucidating the exact pathophysiological mechanisms of MMs and to better understand the pathological interhemispheric connections in epilepsy patients.