Effects of incorporating memory confidence ratings and language handicap modifications on intracarotid amobarbital procedure (Wada test) memory asymmetry scores

Purpose: Intracarotid amobarbital procedure (IAP) memory asymmetry scores a re often considered in determining lateralization of temporal lobe seizure foci. Additionally, these scores sometimes influence treatment plans for ep ilepsy surgery candidates. We examined the effects of two scoring modificat ions on IAP asymmetry scores: incorporating memory confidence ratings (MC), and use of a language handicap (LH) (i.e., adding a point to the memory sc ore with anesthetization of the language-dominant hemisphere), both of whic h could be applied to most IAP protocols despite variations in testings met hods among epilepsy surgery programs. Methods: Sixty-nine consecutive unilateral temporal lobe epilepsy (TLE) pat ients with subsequent good surgical outcomes (Engel I or II) underwent bila teral IAP testing. Confidence ratings were obtained for all memory response s. The incorporation of confidence ratings and the application of a languag e handicap for dominant-hemisphere injections were applied to memory asymme try scores in all combinations, resulting in four scoring methods. Results of the four methods were compared with respect to the proportion of patient s lateralized accurately by each method, Results: No patients were falsely lateralized with any method. percentage o f patients correctly lateralized with each scoring method is shown in Table 2, The results obtained with MC and with MC + LH (67% and 64% of patients accurately lateralized, respectively) were significantly better than result s obtained with LH (55%, p < 0.05). No other differences were significant. Conclusions: Although not statistically superior to standard methods, these results suggest that incorporating memory confidence ratings into IAP prot ocols may increase the likelihood of obtaining asymmetry scores that accura tely lateralize to the hemisphere of seizure onset. In contrast, inclusion of a language handicap for scores obtained with the language-dominant ICA i njection were not helpful and may even decrease the probability of obtainin g clinically useful lateralizing data. These scoring modifications can be a pplied to most IAP protocols.