Monika Turčanová Koprušáková, Egon Kurča, Kamil Javorka, Vladimír Nosáľ
Hemispheric dominance is most often joined with the speech lateralization and hand preference. It is estimated that approximately 90 % of population are right-handers. Speech is localized in left hemisphere in 98 % of them. Excluding strong right-handers most people have only partial hemispheric dominance. In left-handers and ambidextrous is hemispheric dominance less expressed, but speech functions are more often localized to the left hemisphere (60-70 %), 30 % to the right one and 10 % to both hemispheres. The most of these results have come from invasive methods (Wada test, direct cortical stimulation) realized in patients with brain damage, what is often connected to secondary transformation of brain functions to the intact hemisphere. Therefore these results can not be automatically extrapolated to healthy people.