Functional MRI Evaluation of Language Dominance Compared with the Wada Test: a Review and a Novel Sentence Task

Numerous studies tested whether functional magnetic resonance imaging (fMRI) is capable of replacing the Wada test for determination of language dominance. We reviewed 24 studies with 486 patients. The overall mean concordance rate is only about 90%. Furthermore, atypical language dominance is not reliably detected. The objectives of the present study were to develop and validate a new linguistic based fMRI task that specifically activates all putative essential language areas and reliably detects language dominance. The main components of language were assessed with three different tasks (rhyme, synonym, and sentence). It was hypothesized, that the novel sentence task would fulfil the objectives of the present study best because it contained all the main components of language processing, that is phonology, semantic, and syntax. FMRI was performed in healthy right(n=13) and left-handed controls (n=8), and 20 patients at 1.5 T prior to neurosurgery. In controls, activations were quantified by an individual volume of interest analysis. Four neuroimagers tested a visual rating score in the patients group. Interrater agreement and concordance between fMRI and Wada test were calculated. As expected, the sentence task showed high sensitivity and specificity to activate all putative essential language areas. In healthy right-handed controls, the frontal language area was activated by the sentence and synonym task in 100%, and in 73% by the rhyme task. The temporal language area was activated in 100% by the sentence-, in 64% by the synonym-, and 55% by the rhyme task. The sentence task also reliably detected atypical language dominance. Because of low sensitivity and specificity, the rhyme task was not used in patients. In patients, interrater agreement was 0.90 for activations Klemens Gutbrod, Dominik Spring, Nadia Degonda, Dörthe Heinemann, Arto Nirkko, Martinus Hauf, Christoph Ozdoba, Armin Schnider, Gerhard Schroth and Roland Wiest 1 Department of Neurology, Inselspital, Berne University Hospital, and University of Berne 2 Institute of Diagnostic and Interventional Neuroradiology, Inselspital, Berne University Hospital, and University of Berne Departement of Neuropsychology, Swiss Center for Epilepsy, Zurich Division of Neurorehabilitation, University Hospital, Geneva