Effective Memory Stimulus Type and Score Measurement of Wada Memory Test in Lateralization of Temporal Lobe Epilepsy

Kim, Keun Ho; Kim, Ji Eun; Yi, Sang Doe

Abstract

BACKGROUND: The Wada test is not yet standardized among epilepsy surgery centers, which makes it difficult to dis-cern the differences between its results. The objectives of this study were to examine the effects of memory stimulus types in the Wada test and the methods of score measurement of results.
METHODS
We examined the Wada test in 59 patients with temporal lobe epilepsy who had language dominancy in left hemispheres. They underwent surgical treat-ment and were seizure-free for at least until the 1-year follow up. The Wada test was done on the patients using three different protocols during the presurgical evaluations: 1) protocol A; sixteen cards displaying eight line drawings of common objects and eight words, 13 patients, 2) protocol B; eight line drawings of abstract figures, 14 patients, and 3) protocol C; four line drawings of common objects and four line drawings of abstract figures, 32 patients.
RESULTS
Thirty-three patients with RTL (right temporal lobectomy) and 26 patients with LTL (left temporal lobectomy) were not significantly different in demographic and disease characteristics such as age and sex, age at onset, risk factors before 2 years old, epilepsy duration, and Korean Wechsler Adult Intelligence Scale- IQ scores. Patients with RTL rec-ognized significantly more words and line drawings of common objects with a right injection than those with a left injection. Patients with LTL recognized significantly more line drawings of abstract figures and common objects fol-lowing a left injection versus a right injection. Correct rates obtained through discriminant function analysis (100% (A), 64% (B) and 84% (C) were higher than that obtained through cutoff criteria (memory asymmetry scores (3)25%: 82% (A), 62% (B) and 56% (C) ).
CONCLUSIONS
Our study shows that line drawings of common objects as Wada memory stimuli are more useful for the lateralization of the epileptogenic hemisphere than line drawings of abstract figures and words. Discriminant function analysis is also a more effective score measurement than cutoff criteria.