Gestörter Wortabruf im kognitiven Modell und im Gehirn – eine Therapiestudie mit 3 Einzelfällen

Zusammenfassung

In unserer Therapiestudie wurden erstmals kognitive und neuronale Untersuchungsverfahren in einem modellgeleiteten Behandlungsansatz bei 3 Personen mit aphasischen Wortabrufstörungen zusammengeführt: Ausgehend von einer computerunterstützten Feststellung der Störung im Dell-Modell erfolgten störungsspezifische und -unspezifische Therapie zum Vergleich. Durch die Anwendung eines Bild/Wort-Interferenzparadigmas im Magnetresonanztomografen (fMRT) vor und nach Therapie konnten die Veränderungen der Hirnaktivierung durch die Behandlung, das Funktionieren von linguistischen Verarbeitungsschritten und kognitiver Kontrolle (Monitoring), sowie das Ansprechen auf Voraktivierung (Priming) überprüft werden.

Abstract

In the present therapy study, we have for the first time combined cognitive and neural methods of examination in a model-oriented treatment setting for 3 subjects with aphasic word retrieval deficits. Based on a computer-assisted determination of the cognitive lesion in the Dell model, we applied lesion-specific and -unspecific therapies to compare their differential effectiveness. We used a picture/word interference fMRI-paradigm before and after therapy in order to assess therapy-induced changes in brain activation, the functioning of linguistic steps of processing and cognitive control, and the response to priming. As a result, all 3 subjects presented with a lexical-semantic lesion in the Dell model. In 2 subjects, the effectiveness of the lesion-specific semantic therapy was significantly stronger than that of the more unspecific phonological therapy. Due to therapy, brain activations were focused on language regions of the left or both hemispheres. Moreover, all patients recruited parts of the neural network that we had previously found in healthy speakers using the fMRI-paradigm (Abel et al., 2009, NeuroImage). A neural correlate of phonological processing was consistently located in the left superior temporal gyrus. In accordance with the cognitive lesion type, the neural correlate of semantic processing was less pronounced. Furthermore, we detected neural priming for phonological word distractors in all subjects and an additional decrease of cognitive control (monitoring) in 2 subjects. Over and above cognitive-linguistic observations, the individual pattern of brain activations therefore has the potential to indicate the type of disorder, the response to treatment techniques and the optimal therapy procedures.

Schlüsselwörter

Lexikon - Bildgebung - Therapie - Aphasie - Konnektionismus

Key words

word production - brain imaging - therapy - aphasia - connectionism

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