Hippocampal memory function as reflected by the intracarotid sodium methohexital Wada test Fani Andelman a, * , Svetlana Kipervasser b,c , Irith I. Reider-Groswasser c,d , Itzhak Fried a,c,e , Miri Y. Neufeld b,c a Functional Neurosurgery Unit, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel b EEG and Epilepsy Unit, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel c Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel d Section of Neuroradiology, Department of Imaging, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel e Division of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, USA Received 26 May 2006; revised 29 July 2006; accepted 2 August 2006 Available online 30 August 2006 Abstract The intracarotid amobarbital procedure (IAP) determines lateralization of memory function for predicting the risk of amnesia after epilepsy surgery. Shortages of amobarbital led to its substitution with sodium methohexital in the intracarotid methohexital procedure (IMP). We compared IAP scores (32 patients) with IMP scores (20 patients). Wada ipsilateral and contralateral memory scores were analyzed and compared, as was the relationship of these scores to the results of standard neuropsychological memory tests. There was no significant difference in Wada contralateral memory scores (first injection) between the IAP and IMP. Differences between the IAP and IMP in memory scores for the hemisphere ipsilateral to the epileptogenic focus (second injection) were significant (P = 0.01), patients who underwent the IMP manifesting a higher ipsilateral memory reserve. IAP scores related better to standard neu- ropsychological memory test scores than did IMP scores. The anesthetic drug used in Wada testing may affect lateralized memory assess- ment and prediction of postsurgical memory changes. Ó 2006 Elsevier Inc. All rights reserved. Keywords: Wada test; Methohexital; Amobarbital; Brevital; Epilepsy surgery; Memory 1. Introduction During the last two decades, surgical resection of epilep- togenic brain tissue has become an efficient treatment option for carefully selected patients with intractable sei- zures of focal origin [1]. About 80% of individuals with complex partial seizure disorder, particularly of temporal origin, either become seizure-free or enjoy a significant reduction in seizure frequency following surgery [1]. Suc- cess of surgery depends to a great extent on the selection of appropriate patients, which is based on a comprehensive preoperative evaluation to delineate the epileptogenic zone by means of video/EEG monitoring, structural and func- tional neuroimaging, neuropsychological assessment, and Wada testing. The most important use of neuropsychological assess- ment in the context of epilepsy surgery is as an aid in the lateralization of hemispheric dysfunction that may be asso- ciated with the epileptogenic lesion. Because of the associ- ation between temporal lobe epilepsy (TLE) and memory deficits, the assessment of memory has become the most important part of the neuropsychological evaluation of surgical candidates who have TLE. The unique contribu- tion made by each temporal lobe to the support of memory function can, however, be difficult to define with the stan- dard neuropsychological assessment. It has been estab- lished that the degree of accuracy in predicting the 1525-5050/$ - see front matter Ó 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.yebeh.2006.08.001 * Corresponding author. Fax: +9723 697 3992. E-mail address: fani@hermes.tau.ac.il (F. Andelman). www.elsevier.com/locate/yebeh Epilepsy & Behavior 9 (2006) 579–586