Determination of language dominance: Wada test and fMRI compared using a novel sentence task

This study aimed to develop a new linguistic based functional magnetic resonance imaging (fMRI)-sentence decision task that reliably detects hemispheric language dominance.

FMRI was performed in 13 healthy right-handed controls and 20 patients at 1.5 T prior to neurosurgery. The main components of language were assessed with different paradigms (rhyme, synonym, and sentence). In controls, activations were quantified by a 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.

In healthy 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 in 55% by the rhyme task. In the patients group, interrater agreement was .90 for activations in the inferior frontal and .97 in the superior temporal gyrus. Correlation between the WADA test and fMRI was .86 for the sentence, and .89 for the synonym task.

The sentence task provides robust activations in putative essential language areas and can be used for visual analysis of predefined areas to facilitate interpretation of clinical fMRI.