J Korean Soc Magn Reson Med.  1999 Sep;3(3):225-231.

Determination of Dominant Hemishere for Language: Comparison of fMRI and Wada Test

• Ryoo JW
• Na DG
• Hong SB
• Seo DW
• Hong SC
• Choi DS
• Chung WI
• Byun HS

Abstract

PURPOSE
To evaluate the usefulness of functional MR imaging(fMRI) for determination of language dominance compared with Wada test and to assess the lateralization of activated signals according to stimulation task of activated area.
MATERIALS AND METHODS
Functional maps were obtained during word generation task and reading task in twenty patients(16 epilepsy, 4tumor; 17 right-handed, 1 left-handed, 2 ambidextrous). MR examinations were performed at 1.5T scanner with EPI BOLD technique during word generation and word reading tasks. We used SPM program for the postprocessing of image. The threshold for significance was set at p<0.0001 or p<0.001. A lateralization index(LI) was calculated from the number of activated pixels in three hemispheric areas(whole hemisphere, frontal lobe, and temporoparietal lobe. The LIs of fMRI and Wada test were compared according to stimulation task and area for calculation of LI.
RESULTS
During the Wada test, sixteen patients had the left language dominance and four patients had right dominance. The language dominance determined by LI of fMRI in each hemisphere was concordant with the result of Wada in 19(95%) by word generation task and in 15(75%) by reading task. At word generation task, the concordance rate was higher with LI calculated on whole hemisphere than that on frontal(80%) or temporoparietal lobe(90%). Correlation between the LIs of Wada and fMRI was significant(r=0.74)
CONCLUSION
In fMRI word generation task produced stronger activation of language areas and showed more accurate lateralization reading task. The concordance rate of and Wada test was higher with LI calculated on whole hemisphere than on frontal or temporoparietal lobe.

Keyword

Brain; Functional MRI; Language; Wada test

MeSH Terms

Brain
Epilepsy
Frontal Lobe
Humans
Magnetic Resonance Imaging*