Unsuspected atypical hemispheric dominance for language as determined by fMRI

Purpose: We sought to illustrate the value of functional magnetic resonance imaging (fMRI) in the presurgical assessment of hemispheric dominance for language by means of an illustrative case report. Methods: fMRI with two language paradigms was performed in a right-handed patient without familial sinistrality suffering from a left frontal focal epilepsy. Results: Both fMRI paradigms revealed unequivocally lateralized right hemispheric activation. Atypical language representation was confirmed by Wada test. The further presurgical workup could be restricted to subdural strip recordings instead of the initially intended grid implantation. After resective surgery, no language deficits were apparent. Conclusions: Hemispheric dominance for language should be assessed by fMRI in all patients before surgery in areas potentially relevant for language in either cerebral hemisphere. fMRI may influence the further diagnostic workup and should be performed before other invasive diagnostic procedures.