Preoperative versus postoperative neuropsychological sequelae of arteriovenous malformations.

In a cohort of 14 patients suffering from cerebral arteriovenous malformations (AVM), neuropsychological functioning was examined before and after AVM resection. Improvements after surgery were assumed to be due to enhanced neurocognitive functions associated with the hemisphere ipsilateral to the AVM, and to a lesser extent, with the contralateral hemisphere. Before surgical intervention, the performances of AVM patients were deficient relative to matched normals. Postoperatively, neuropsychological gains were observed particularly in the areas of learning, memory, and higher integrative thought, not only for ipsilateral, but also for contralateral functioning. Contralateral and ipsilateral improvement is consistent with the premise that cerebrovascular steal is lessened; thus, neurosurgical intervention to eliminate arteriovenous shunts was found to result in overall neurobehavioral gains.