Discrepant findings for Wada test and functional magnetic resonance imaging with regard to language function: use of electrocortical stimulation mapping to confirm results. Case report.

Abstract

The Wada test is still considered the gold standard for determining the language-dominant hemisphere prior to brain surgery. The authors report on a 34-year-old right-handed woman whose Wada test results indicated that the right hemisphere was dominant for language. In contrast, functional magnetic resonance (fMR) imaging was indicative of bilaterally represented language functions. Activation in the left hemisphere demonstrated on fMR imaging was most pronounced in the Broca area. Importantly, fMR imaging results in this area were confirmed on electrocortical stimulation mapping. These contradictory findings indicated that a right hemispherre dominance for language according to the Wada test should be questioned and verified using electrocortical stimulation. Nonetheless, the question remains whether involvement of these areas in the left frontal hemisphere is critical for language, as these were spared during surgery.