Abstracts

Wada Testing is a commonly used procedure to establish the distribution of language and memory, . Wada is associated with angiography complications so some centers limit its use. Many centers use Wadas in all patients while others do not where no evidence of atypical language distribution is found. We retrospectively reviewed the Wada results to determine if handedness was a successful predictor of hemispheric language distribution., We reviewed the evaluations of patients from 1991 to 2001 for the presence of valid Wada Test and an assessment of handedness. Our center performs Wada Tests on all potential surgical candidates. We found 203 patients. The Wada procedure was similar to that described by Loring et al. With the patient in the supine position with arms outstretched, 125 mg of sodium amytal was injected by hand over a 5-second interval into the internal carotid artery with additional 25- or 50-mg bolus were injected till contralateral flaccid hemiplegia occurred. Simultaneous EEG was performed. Counting disruption and ability to follow two simple midline commands just after injection was numerically rated. Numerical ratings were then made on four language tasks: (1) comprehension of three one- and two-step commands of increasing difficulty (the most difficulty including inverted syntax), (2) naming objects or parts of objects depicted in line drawings, (3) phrase repetition, and (4) sentence reading. All ratings used a 0 to 3 scale, with lower scores reflecting poorer performance. Also included in the scoring was a rating of paraphasic errors, based on the total number of errors during each series of language tests (0, more than 5 errors; 1, 3 to 5 errors; 2, 1 to 2 errors; and 3, no errors). Only trials conducted before return of motor functioning were included for a total score of 33 on the language measures was possible.
Wada hemisphere scores are the percent correct divided by total possible score multipled by 100., 167 of the 203 patients were right handed, 29 patients were left handed, and 7 demonstrated mixed handedness. We found evidence of right hemisphere language in 129 of 203 patients. Table One shows the frequency of different degrees of right hemisphere language assessed by Wada testing distributed by handedness., We found in our retrospective assessment that handedness does not provide reliable hemisphere of language prediction. We conclude that Wada testing is essential to determine if an atypical language distribution exists. Wada testing should be performed in all pre-surgical assessments.[table1],