Abstracts

Rationale: The intracarotid amobarbitol test (Wada) remains an important tool for predicting postoperative memory decline in individuals with intractable temporal lobe epilepsy. The effects of inadequate hippocampal perfusion of Amobarbitol and sedation on the accuracy of intracaroid artery Wada tests have been raised. The superselective posterior cerebral artery Wada anesthetizes the posterior aspect of the hippocampus without disrupting the patient s primary language areas or frontal lobes. This is thought to improve the prediction of postoperative memory impairment as sedation is reduced relative to the traditional Wada. Historically, visual memory stimuli used for the selective Wada test have been three-dimensional (3-D). Technological developments in tablet computers have sparked interest in replacing 3-D stimuli with two-dimensional (2-D) line drawings. Use of tablet-based stimuli would decrease the time needed to complete the learning portion of the Wada and increase standardization. Methods: Descriptive study of 6 patients with intractable temporal lobe epilepsy who underwent a traditional intracartoid Wada procedure and failed or had paradoxical results and underwent a selective Wada. The procedure included placement of an endovascular micro-catheter in the P1/P2 junction of the posterior circulation with subsequent injection of 75 mg of Amobarbital. Memory test items (8 verbal, 8 visual) were presented for approximately 5 seconds via an iPad in their unaffected visual field immediately following the injection. All patients demonstrated expected visual field deficit that was maintained throughout the procedure without evidence of sedation, or extraoccular or language impairment. Recognition was tested 12-minutes post-injection.Results: All subjects obtained a passing score on the selective Wada test following presumed ipsilateral hemisphere injection (based on video-EEG monitoring and neuroimaging findings) of Amobarbital. The use of the iPad to present 2-D line drawings did not appear to interfere with the ability to learn or recognize visual information.Conclusions: Results support the use of new tablet computer technology such as the iPad for presentation of 2-D visual stimuli during the selective Wada procedure. The increased efficiency and standardization offered by using an iPad based Wada protocol appears to be effective for assessing the potential for postoperative memory decline in individuals with intractable temporal lobe epilepsy.