Abstracts

Presurgical evaluation of language and memory using the internal carotid WADA (ICAW) procedure is a standard approach for patients with medically intractable epilepsy. However, ICAW results often provide equivocal memory data, especially in cases with a dominant hemisphere seizure focus, as a result of aphasia with amytal injection. Therefore, selective preoperative intracarotid amytal procedures (IAP) have been developed to target hippocampal functions. Several variations of the selective IAP have been reported and include selective injections of amytal into: (1) anterior choroidal artery (AChA) and (2) posterior cerebral artery (PCA). This report focuses on a clinical series of patients who had selective amytal injections through the internal carotid artery (ICA) with temporary balloon catheter occlusion of the distal ICA beyond the AchA origin., Twenty-seven patients with intractable epilepsy were evaluated using the distal ICA occlusion approach. Three patients underwent selective procedures for both hemispheres while the remaining 24 had selective injections targeting the hippocampus in the affected hemisphere along with a standard IAP of the contralateral hemisphere. Of these patients, 7 (26%) had previously [apos]failed[apos] standard IAP injections given generalized anesthetic effects on the dominant hemisphere. Memory and language were evaluated in all patients using a modified McGill protocol that required learning of 3 visual objects and 3 verbal items after selective amytal injection. Subsequent free and cued recall of these items along with recognition was completed after resolution of the patient[apos]s homonymous hemianopsia., All patients demonstrated homonymous hemianopsia with the selective injection and 78% showed brief temporal slowing on EEG ipsilateral to the injected hemisphere. Evaluation of memory showed encoding specific effects on memory items for 78% of cases where selective left-sided injection resulted in proportionally poorer recall of verbally encoded items. In the 3 right-sided selective IAPs, no memory encoding effects were observed. This [apos]selective[apos] memory effect was independent of the presence of temporal slowing on EEG., Selective WADA procedures targeting the hippocampus through temporary occlusion of the supra-clinoidal ICA and injection through the AchA can be an effective tool in the presurgical evaluation of patients when evaluating information on memory preservation post surgical resection of a seizure focus. Further, selective WADA procedures generally show memory effects that are consistent with the verbal or visual presentation mode of the memory items used in IAP assessments.,