Abstracts

Objective: At the end of this activity the participants should be able to discuss the relationships between baseline neuropsychological memory testing, Wada memory results, and memory outcome following left ATL
Decline in recent memory function is a risk following left anterior temporal lobectomy (ATL). A variety of approaches have been used to predict risk to memory function following surgery, although most studies have not simultaneously included multiple behavioral measures to determine the relative contribution of each in assessing risk. In the present study, we report both baseline memory performance and Wada memory scores and assess their ability to forecast memory chance following left ATL.
METHODS: 44 patients who had undergone left ATL were retrospectively identified after meeting the criteria of having undergone successful bilateral Wada memory testing preoperatively and having completed the WMS-R Logical Memory paragraph recall preoperatively and again during follow-up neuropsychological assessment. Wada memory was tested by presenting 8 real objects begining approximately 45 seconds post-injection of 100-125 amobarbital and assessing object recognition after return to baseline. The predictor variables for Logical Memory II change included the interhemispheric Wada memory asymmetry and baseline Logical Memory II performance.
RESULTS: The average Wada memory asymmetry was 2.45 objects (SD=3.2). Baseline Logical Memory II was 14.4 (SD=8.5) and the average Logical Memory II decline was 4.2 (SD=9.1). Data were analyzed using a simple linear regression model using baseline Logical Memory II and Wada memory asymmetris as predictors of pre- to post-operative LM II change. Baseline Logical Memory II was highly related to LM II decline following ATL (p=.000002; R-squared =.418). The inclusion of the Wada asymmetry score produced a significant increase in post-operative memory change prediction (incremental R-squared = .110; p=.002), resulting in a total R-squared with both variables in the model of .537.
CONCLUSIONS: These results confirm previous reports that patients with higher baseline memory performance are more likely to display a greater memory decline following left ATL and that Wada memory scores are also related to post-operative memory decline. By itself, baseline Logical Memory II accounted for approximately 40% of the post-operative memory change. Including Wada memory in the prediction model, however, increased the predictive ability of the model by over 10%. Thus, both measures are not completely redundant in their predictive ability, and each provides some independent measure of outcome prediction of memory change.