Remote effects of cerebrovascular accidents: visual evoked potentials and electrophysiological coupling

Performance on two electrophysiological tasks, EEG and VEP, of patients who had sustained either a right or left middle cerebral artery CVA was examined. The occurrence of a stroke disrupted electrophysiological functioning of brain regions beyond the ischemic focus of the CVA, and these remote effects persisted beyond the period of transient diaschisis. CVA reduced the electrophysiological concordance between brain regions as reflected in EEG coupling and VEP intercorrelation procedures, and the disruption was more severe if the CVA affected the right as opposed to left middle cerebral artery. Techniques for characterizing the abnormal event-related potentials of CVA subjects are reviewed, and some possible theoretical explanations of the functional communication and remote effects are offered.