Two right-handed patients with large, left-hemisphere arteriovenous malformations (AVM) underwent serial endovascular embolization and neuropsychological testing procedures. One patient presented with hemorrhage, hemiplegia, and aphasia; the other patient presented with a seizure only with multiple cognitive impairments. Case 1 was assessed for motor-sensory skills in the left hand and for visual recall (nondominant hemisphere). Case 2 was administered a more global assessment of cognitive functions. Both patients demonstrated significant improvements in neuropsychological functions 1 month following endovascular embolization with >50% reduction in AVM volume. The nature and extent of these improvements are discussed with respect to intervention-related, reversed impairments.