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Parkinson’s Disease
Volume 2015, Article ID 943572, 10 pages
Research Article

Cognitive Reserve in Parkinson’s Disease: The Effects of Welsh-English Bilingualism on Executive Function

1Bangor University, Gwynedd, Bangor LL57 2DG, UK
2Betsi Cadwaladr University Health Board, Llandudno Hospital, Conwy LL30 1LB, UK
3NISCHR CRC North Wales Research Network, Bangor University, Gwynedd, Bangor LL57 2PZ, UK
4University of Exeter, Devon, Exeter EX4 4QG, UK
5Rotman Research Institute, Toronto, ON, Canada M6A 2E1
6York University, Toronto, ON, Canada M3J 1P3
7Florida International University, Miami, FL 33199, USA

Received 29 September 2014; Revised 3 March 2015; Accepted 11 March 2015

Academic Editor: Francisco Grandas

Copyright © 2015 John V. Hindle 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.


Objective. Bilingualism has been shown to benefit executive function (EF) and delay the onset of Alzheimer’s disease. This study aims at examining whether a bilingual advantage applies to EF in Parkinson’s disease (PD). Method. In a cross-sectional outpatient cohort of monolingual English () and bilingual Welsh/English () speakers with PD we evaluated the effects of bilingualism compared with monolingualism on performance on EF tasks. In bilinguals we also assessed the effects of the degree of daily usage of each language and the degree of bilingualism. Results. Monolinguals showed an advantage in performance of language tests. There were no differences in performance of EF tests in monolinguals and bilinguals. Those who used Welsh less in daily life had better performance on one test of English vocabulary. The degree of bilingualism correlated with one test of nonverbal reasoning and one of working memory but with no other tests of EF. Discussion. The reasons why the expected benefit in EF in Welsh-English bilinguals with PD was not found require further study. Future studies in PD should include other language pairs, analysis of the effects of the degree of bilingualism, and longitudinal analysis of cognitive decline or dementia together with structural or functional neuroimaging.