Case Report Multimodal functional mapping of sensorimotor cortex prior to resection of an epileptogenic perirolandic lesion Heidi E. Kirsch, a, * Jehuda P. Sepkuty, b and Nathan E. Crone b a UCSF Epilepsy Center, Department of Neurology, University of California San Francisco School of Medicine, San Francisco, CA, USA b Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA Received 15 January 2004; revised 5 February 2004; accepted 10 February 2004 Available online 19 March 2004 Abstract The effects of chronic epileptogenic lesions on functional anatomy are under debate. Our recent experience during mapping and resection of a lesion in sensorimotor cortex supports the idea that epileptogenic lesions may prompt development of alternate cortical motor representations. Multimodal mapping may uncover alternate areas of functionality that make surgery feasible even when conventional neuroanatomy suggests otherwise. Newer methods such as electrocorticographic spectral analysis may com- plement traditional electrical cortical stimulation mapping. Ó 2004 Elsevier Inc. All rights reserved. Keywords: Functional mapping; Epilepsy surgery; Electrocorticography; Electrocorticographic spectral analysis; Cortical plasticity; Motor cortex 1. Introduction Evidence from electrical cortical stimulation (ECS) mapping suggests that sensorimotor topography may vary widely [1,2]. In addition, chronic cortical lesions may lead to reorganization of functional anatomy, as demonstrated in primates and in humans [for a re- view, see 3]. This reorganization presumably occurs by compensatory cortical synaptic reorganization like that observed after experimental manipulation of af- ferent pathways in animals. With slow-growing lesions of sensorimotor cortex, intraoperative ECS has been used to guide excision to spare function. In some cases, multiple representations for the upper extremity have been identified that were not apparent with ECS before resection, but were demonstrated immediately afterward, suggesting that alternate cortical represen- tations were available [e.g., 4]. Before resection near essential cortical regions, identification of alternate cortical representations might mitigate postoperative deficits. This principle is illustrated by a patient with intrac- table epilepsy from a chronic perirolandic lesion. Pro- longed EEG monitoring showed ictal onset in sensorimotor cortex, complicating surgical planning. Ictal electrocorticographic (ECoG) recordings located the epileptogenic zone in sensorimotor regions identified through extraoperative ECS mapping. However, func- tional mapping with multiple complementary methods revealed additional surrounding cortical regions that had similar motor function. This allowed us to postulate that alternate cortical representations might minimize the risk of postlesionectomy deficits. 2. Case Our subject was an 18-year-old right handed man with multiple cavernous angiomas (Fig. 1) and intractable simple partial seizures of the right arm, onset at C1/C3/ CP3 scalp electrodes. He also had rare complex partial seizures without lateralizing features (presumably from another source). He underwent implantation of subdural electrodes (platinum–iridium; 2.3-mm-diameter exposed surface; 1-cm center-to-center spacing; Ad-Tech, Racine, WI, USA) to better define his seizure focus (Fig. 2). * Corresponding author. Fax: 1-415-252-2837. E-mail address: heidi@itsa.ucsf.edu (H.E. Kirsch). 1525-5050/$ - see front matter Ó 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2004.02.001 Epilepsy & Behavior 5 (2004) 407–410 Epilepsy & Behavior www.elsevier.com/locate/yebeh