Behavioural relevance of atypical language lateralization in healthy subjects

In most humans, language is lateralized to the left side of the brain. It h as been speculated that this hemispheric specialization is a prerequisite f or the full realization of linguistic potential. Using standardized questio nnaires and performance measures, we attempted to determine if there are be havioural correlates of atypical, i.e. right-hemispheric and bilateral, lan guage lateralization. The side and degree of language lateralization were d etermined by measuring the hemispheric perfusion differences by functional transcranial Doppler ultrasonography during a word generation task in healt hy volunteers. Subjects with left (n = 264), bilateral (n = 31) or right (n = 31) hemisphere language representation did not differ significantly with respect to mastery of foreign languages, academic achievement, artistic ta lents, verbal fluency or (as assessed in a representative subgroup) in inte lligence or speed of linguistic processing. These findings suggest that aty pical hemispheric specialization for language, i.e. right-hemisphere or bil ateral specialization, is not associated with major impairments of linguist ic faculties in otherwise healthy subjects.