[Hemispheric dominance for language and functional magnetic resonance: a comparison of three tasks]

The object of this study to analyse and compare the efficacy of the classic language tasks (repetition, phonological fluency and lexical decision), for the purpose of identifying the dominant hemisphere for language by means of functional magnetic resonance.

The three tasks were performance with a groups of 10 right handed subjects with ages of 22 to 40 years. The examination was carried out using a 1,5 T MRI apparatus. An eight sequence of planar echo gradient (BOLD technique) was used, making the oblique axial plane coincide with the line between the anterior and posterior commissures (CA CP line) and covering the entire brain.

Dominance was calculated by means of the lateralization index, comparing the activation in each hemisphere in two locations: first, taking account the temporal lobe together with the right and left frontal lobes, and second, taking into account only the right and left frontal lobes.

The result indicate that the most effective test for obtaining the dominant hemisphere was the one for phonological fluency, this task activated the frontal areas, which showed greater participation in the left hemisphere.