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Neural Plasticity
Volume 2016, Article ID 8797086, 22 pages
http://dx.doi.org/10.1155/2016/8797086
Research Article

The Role of the Cognitive Control System in Recovery from Bilingual Aphasia: A Multiple Single-Case fMRI Study

1Neurology Unit, Department of Medicine, Faculty of Sciences, University of Fribourg, Fribourg, Switzerland
2Neurorehabilitation Department, University Hospital, University of Geneva, Geneva, Switzerland
3Neuropsychology Unit, Fribourg Cantonal Hospital, Fribourg, Switzerland
4Center for Neurolinguistics and Psycholinguistics, San Raffaele University and Scientific Institute San Raffaele, Milan, Italy

Received 13 June 2016; Revised 15 September 2016; Accepted 12 October 2016

Academic Editor: Swathi Kiran

Copyright © 2016 Narges Radman et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Aphasia in bilingual patients is a therapeutic challenge since both languages can be impacted by the same lesion. Language control has been suggested to play an important role in the recovery of first (L1) and second (L2) language in bilingual aphasia following stroke. To test this hypothesis, we collected behavioral measures of language production (general aphasia evaluation and picture naming) in each language and language control (linguistic and nonlinguistic switching tasks), as well as fMRI during a naming task at one and four months following stroke in five bilingual patients suffering from poststroke aphasia. We further applied dynamic causal modelling (DCM) analyses to the connections between language and control brain areas. Three patients showed parallel recovery in language production, one patient improved in L1, and one improved in L2 only. Language-control functions improved in two patients. Consistent with the dynamic view of language recovery, DCM analyses showed a higher connectedness between language and control areas in the language with the better recovery. Moreover, similar degrees of connectedness between language and control areas were found in the patients who recovered in both languages. Our data suggest that engagement of the interconnected language-control network is crucial in the recovery of languages.