Effects of incorporating memory confidence ratings and language handicap modifications on intracarotid amobarbital procedure (Wada test) memory asymmetry scores.
OBJECTIVE
Intracarotid amobarbital procedure (IAP) memory asymmetry scores are often considered in determining lateralization of temporal lobe seizure foci. Additionally, these scores sometimes influence treatment plans for epilepsy surgery candidates. We examined the effects of two scoring modifications on IAP asymmetry scores: incorporating memory confidence ratings (MC), and use of a language handicap (LH) (i.e., adding a point to the memory score with anesthetization of the language-dominant hemisphere), both of which could be applied to most IAP protocols despite variations in testing methods among epilepsy surgery programs.


METHODS
Sixty-nine consecutive unilateral temporal lobe epilepsy (TLE) patients with subsequent good surgical outcomes (Engel I or II) underwent bilateral IAP testing. Confidence ratings were obtained for all memory responses. The incorporation of confidence ratings and the application of a language handicap for dominant-hemisphere injections were applied to memory asymmetry scores in all combinations, resulting in four scoring methods. Results of the four methods were compared with respect to the proportion of patients lateralized accurately by each method.


RESULTS
No patients were falsely lateralized with any method. Percentage of 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 results 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 protocols may increase the likelihood of obtaining asymmetry scores that accurately lateralize to the hemisphere of seizure onset. In contrast, inclusion of a language handicap for scores obtained with the language-dominant ICA injection were not helpful and may even decrease the probability of obtaining clinically useful lateralizing data. These scoring modifications can be applied to most IAP protocols.
Hamberger
M J
MJ
Department of Neurology, College of Physicians and Surgeons of Columbia University, Columbia-Presbyterian Medical Center, New York, New York, USA. mh61@columbia.edu
Hirsch
L J
LJ
D000328:Adult; D000654:Amobarbital / Q000008:administration & dosage / Q000494:pharmacology; D002343:Carotid Artery, Internal; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis* / Q000503:physiopathology; D007839:Functional Laterality / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007269:Injections, Intra-Arterial; D007802:Language; D008568:Memory / Q000187:drug effects* / Q000502:physiology; D013702:Temporal Lobe / Q000187:drug effects / Q000503:physiopathology*
D000654:Amobarbital