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

PublishedJournal ArticleObjective. 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 (n = 57) and bilingual Welsh/English (n = 46) 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.This study was funded by Economic and Social Research Council Grant RES-062-23-1931 awarded to Linda Clare (PI), John V. Hindle, Virginia C. Mueller Gathercole, Enlli M. Thomas, Ellen Bialystok, Fergus I. M. Craik, and Christopher J. Whitaker

Explaining children’s over-use of definites in partitive contexts

Partitive contexts are those in which a set of similar individuals has been introduced, and the speaker needs to refer to one of them. If that referent has not yet been individualized in the context, the only adult-like option is to refer to it with an indefinite. But in such contexts, children have been shown to often produce (illicit) definites. In comprehension, if children are made to identify a referent in a partitive context, they do not always interpret correctly the definiteness clues in the input, and tend to interpret definites as if they were indefinite. This article reviews production and comprehension studies in light of new experimental data, and argues that children’s errors in this type of context are due to processing limitations