John Libbey Eurotext

Electrical Wada for pre-surgical memory testing: a case report Volume 24, issue 2, April 2022

Figures

  • Figure 1

Tables

Authors
1 Center for Multimodal Imaging and Genetics, University of California, San Diego, CA, USA
2 Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
3 Department of Biomedical Engineering, Georgia Tech, Atlanta, GA, USA
4 Department of Radiology, Emory University, GA, USA
5 Department of Psychiatry, University of California, San Diego, CA, USA
6 San Diego State University/University of California San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA
7 Department of Neurosurgery, Emory University, Atlanta, GA, USA
8 Department of Pediatrics, Emory University School of Medicine, Atlanta, GA, USA
9 Department of Neurology, University of Washington, Seattle, WA, USA
* Correspondence: Daniel L. Drane Departments of Neurology and Pediatrics, Emory University School of Medicine, Woodruff Memorial Research Building, 101 Woodruff Circle, Suite 6111, Atlanta, GA 30322, USA

We report a case study of a surgical candidate, a 51-year-old woman with left temporal lobe epilepsy, who failed a left injection intracarotid amobarbital procedure (e.g., Wada test), scoring 0 of 8 items. This raised concerns for postoperative memory decline. However, the patient was uninterested in a neuromodulatory approach and wished to be reconsidered for surgery. A stereotactic laser amygdalohippocampotomy (SLAH) was considered, encouraging the need for an alternative test to evaluate risk of memory decline. We developed a novel approach to testing memory during stimulation of a depth electrode implanted in the hippocampus, i.e., an electric Wada. During multiple stimulation trials across a range of amplitudes, the patient scored up to 8 of 8 items, which suggested strong contralateral memory support. The surgical team proceeded with a radiofrequency ablation and a subsequent SLAH. The patient remains seizure-free at 12 months post SLAH with no evidence of verbal or visuospatial memory decline based on a post-surgical neuropsychological battery. We believe that this case study provides a proof of concept for the feasibility and possible utility of an electric version of the Wada procedure. Future studies are needed to develop an optimal paradigm and to validate this approach.