Abstracts

Rationale: The Wada test is a standard method used to predict and avoid possible post-surgical memory deficit in patients with temporal lobe epilepsy. However, there are a number of patients who remain unresolved. We can extend certain ambiguous Wada outcomes by intra-operative thermal inactivation (hippocampal cooling) during surgery. The research examines the probable predictive validity of hippocampal cooling on protection of post-surgical memory in patients who underwent anterior temporal lobectomy. Methods: We examined a group of 70 patients by the Wada test. Fifty one of them were in risk of post-surgery memory deficit. 55.7 percent of patients had a seizures onset zone in the dominant hemisphere. These patients were divided into groups according to the Wada test results. Per-operative hippocampal cooling was indicated in 22 of these patients (mean age = 35.0 ± 9.36) (For frequency of groups see results.). The memory functions were assessed by the Wechsler Memory Test - III 3 to 6 months before the surgery and approximately 1 year after it. Results: We have compared pre-surgical / post-surgical memory quotients (MQ) changes and percentages of Engel I outcomes (%) in four groups. A - 19 patients with successful Wada results 100.0/96.8 (89.4 %) B - 17 patients with unsuccessful Wada tests and successful hippocampal cooling 98.7/97.8 (76,4%) C - 5 patients with unsuccessful Wada and failed cooling 90.2/90.5 (100 %) D - 29 patients with unsuccessful Wada and with no cooling 97.8/96.6 (75.8%). The groups did not differ significantly in both pre-surgical [Kruskal-Wallis WChi-square(d.f.=3)=1.47; p=n.s.] and post-surgical [K-W Chi-square(d.f.=3)=0,755; p=n.s.], MQ evaluations and frequency of the Engel’s #1 outcome [Chi-square(d.f.=2)=1,47;p=n.s.]. The results of pre- and post-surgical examinations did not differentiate significantly between groups [K-W Chi-square(d.f.=3)=0,896; p=n.s.] We did not find any significant differences among subgroups restricted to the patients who underwent dominant hemisphere surgery. Conclusions: In general, despite the low frequency, the MQ and successfulness of surgery did not decrease after per-surgical cooling in patients at risk of mnestic deficit indicated by the Wada test. Possible problematic co-operation with a patient in the course of awake surgery should be taken into consideration. The restlessness of a patient and necessary pharmacological sedation made testing impossible in approximately one quarter of our patients.