Dissociating semantic and phonological verbal fluency

Abstract: Semantic and phonological verbal fluency tasks, that require the examinee to produce words to a given semantic (i.e. category) or phonological (i.e. letter) cue, are often used in clinical and experimental neuropsychology to assess language abilities and executive functioning. As in the two task variants word generation is believed to involve different types of search processes, it is also implicitly assumed that semantic and phonological verbal fluency differ both in their underlying cognitive processes and neural correlates involved for successful retrieval. However, in previously published factor analyses, semantic and phonological verbal fluency loaded on only one common factor. Moreover, the often assumed double dissociation between lesions in temporal vs. frontal brain regions and impairments in semantic vs. phonological verbal fluency was neither explicitly tested nor shown.
By using exploratory factor analyses in healthy participants and further confirmatory factor analyses in chronic stroke patients with measures of semantic and phonological verbal fluency only, the first study of this thesis showed that inter-individual differences in semantic and phonological verbal fluency are represented by two factors. These two factors show both common and distinct shares of variance and can therefore be interpreted as evidence for the involvement of both distinct and common cognitive processes.
The second study of this thesis used voxel-based lesion-behavior mapping analyses in chronic stroke patients and results revealed that a specific impairment in semantic vs. phonological verbal fluency resulted from lesions in temporal vs. frontal brain regions, respectively. Further analyses showed that a specific impairment depends on the exact localization, especially for lesions in frontal brain areas and that semantic and phonological verbal fluency may be impaired to a similar extent.
In order to confirm the clinical utility of the German version of the verbal fluency task, applied in the previous studies, the third study was concerned with its psychometric properties by taking particularly the impact of item difficulty into account. Results indicate good test-score reliability, criterion-related concurrent validity, and test-retest reliability, and reliability clearly benefits from aggregation across multiple items.
Overall results demonstrate that semantic and phonological fluency are based on clearly distinct but also common sets of cognitive processes and that they are differentially mediated by temporal and frontal brain areas, respectively. Furthermore, for a reliable assessment of verbal fluency, item difficulty should be considered. Taken together, this thesis contributes to a more comprehensive understanding of verbal fluency and its underlying cognitive and neural correlates

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Universität Freiburg, Dissertation, 2018

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2018
• Urheber: Schmidt, Charlotte Sophie
• Beteiligte Personen und Organisationen: Kaller, Christoph ; Heinrichs, Markus ; Albert-Ludwigs-Universität Freiburg. Wirtschafts- und Verhaltenswissenschaftliche Fakultät

Weitere Informationen

• DOI: 10.6094/UNIFR/17039
• URN: urn:nbn:de:bsz:25-freidok-170394
• Rechteinformation: Kein Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 2025-03-25T13:42:57+0100