The Wada test: An analysis of language and memory functioning

Patients with intractable epilepsy (N = 395) underwent the Wada test procedure prior to surgical exicison of damaged tissue. A Factorial Multivariate Analysis of Variance (MANOVA) was conducted on language dominance, side of seizure focus (left versus right hemisphere), and location of seizure focus (temporal versus extratemporal lobe) with relation to Wada test memory scores. Language dominance was examined according to five categories: left only, left > right, left = right, right > left, and right only. This dissertation also compared the pattern of performance on Wada test memory scores with pre-operative Rey Auditory Verbal Learning Test (RAVLT) memory scores. This was in an effort to verify the pattern of Wada test memory scores with a paper-and-pencil measure. Results of the MANOVA analysis revealed that evaluation of the side of seizure focus and language dominance seem more predictive of functioning on the Wada test than location of the focus. The lack of significant results on the RAVLT analysis suggested that the brain was able to compensate for the "damaged" hemisphere through the use of both hemispheres for language and memory functioning.;Findings from this study suggest that Wada memory scores are higher in individuals with right seizure focus and left hemisphere language dominance. Due to the greater incidence and greater statistical reliability of left hemisphere language dominance, clinicians may be more confident in statements concerning language dominance during the Wada test with right hemisphere injection. A less conservative approach may be taken when undergoing surgery in the right temporal lobe with left hemisphere language dominance, since most language and memory functioning will be mediated by the left hemisphere.