title: Investigating language lateralization during phonological and semantic fluency tasks using functional transcranial Doppler sonography.
abstract: Although there is consensus that the left hemisphere plays a critical role in language processing, some questions remain. Here we examine the influence of overt versus covert speech production on lateralization, the relationship between lateralization and behavioural measures of language performance and the strength of lateralization across the subcomponents of language. The present study used functional transcranial Doppler sonography (fTCD) to investigate lateralization of phonological and semantic fluency during both overt and covert word generation in right-handed adults. The laterality index (LI) was left lateralized in all conditions, and there was no difference in the strength of LI between overt and covert speech. This supports the validity of using overt speech in fTCD studies, another benefit of which is a reliable measure of speech production.
authors.affiliation: a ESRC Deafness, Cognition and Language Research Centre , University College London , London , UK.
authors.forename: Eva
authors.initials: E
authors.lastname: Gutierrez-Sigut
authors.forename: Heather
authors.initials: H
authors.lastname: Payne
authors.forename: Mairéad
authors.initials: M
authors.lastname: MacSweeney
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D012660:Semantics; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult
keywords: Language lateralization; Phonological fluency; Semantic fluency; Word generation; fTCD