Cut-off Value of Wada Memory Score in Verbal and Visual Memory Domain

ABSTRACT

BACKGROUND: The cut-off value which determine pass or fail in Wada memory test has not been thoroughly studied, especially in regard to modality-specific memory domains. To investigate the optimal cut-off value, we tried to know what value is appropriate to forecast good postoperative memory outcome in verbal and visual memory domains. METHODS: Eighteen temporal lobe epilepsy patients underwent preoperative Wada test and pre- and postoperative neuropsychological evaluation. Corrected Wada memory score (cWMS) was calculated by ipsilateral Wada retention score divided by pre-Wada score. As a measure of postoperative memory outcome, neuropsycholgical asymmetry index (NPAI) was defined as [(postoperative memory score ? Preoperative memory score) / their mean] and analyzed in verbal and visual memory domains respectively. We made six arbitrary cut-off cWMS values (40, 50, 60, 70, 80, and 90%) and dichotomized the patients into pass or fail group at each arbitrary cut-off value. Verbal and visual NPAIs were compared statistically between two groups. RESULTS: Verbal NPAIs were significantly different between pass and fail groups at 80% cut-off value (p=0.044). Visual NPAIs were significantly different between two groups at 50% (p=0.043) and 60% (p=0.003) cut-off values. CONCLUSIONS: Higher cut-off values may be better for differentiating good and poor postoperative memory outcomes in verbal memory domain, and, in contrast, lower cut-off values may be better in visual memory domain. The verbal and visual memory in Wada test should be analyzed with different cut-off values.