Abstracts

The Wada test is an important component of the presurgical evaluation for epilepsy, and is performed at most epilepsy centers. It is well known to be a very cursory test with many limitations. Occasionally, the results are such that the test is repeated, but there are very little data on the outcome of repeated Wada tests. We reviewed all Wada tests performed by a single epileptologist over a 6 year period, and identified patients who had more than one Wada test. Only patients in whom the entire procedure was repated were included. Tests were performed according to the Loring protocol, using either amobarbital or methohexital. All patients who underwent Wada testing were being considered for a temporal lobectomy. Over the 6 year period, a total of 201 patients underwent a Wada test. Of those, 14(7%) patients had the test twice. Reasons for repeating the test were: 5 invalid results due to confounding factor (excessive sedation in 3, no drug effect in 1, anxiety attck in 1); 9 [quot]reversed[quot] memory scores without obvious cause, thus prohibiting surgery. Of the 5 tests repeated due to an invalid test, all had a successful repeat test allowing for a decision (4 had surgery, one did not). Of the 9 [quot]reversed[quot] Wadas, 8 repeat tests were no longer [quot]reversed[quot] and allowed surgery, and one remained reversed and prohibited surgery. Language representation never changed on repeat testing. Repeating Wada tests is well worthwhile, whether there is an obvious cause for invalid data or the results are [quot]reversed,[quot] as there is significant test-retest variability for memory results.