Language deterioration in bilingual Alzheimer's disease patients: A longitudinal study

Abstract

In the context of bilingual research, little is known about the effects of neurodegenerative disorders (NDs) on the processing of two languages in a bilingual. In a recent cross-sectional study, we showed that Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD) had similar effects on lexico-semantic processes in the two languages of highly proficient bilinguals (Costa et al., Neuropsychologia, 2012, 50, 740-53). In the present longitudinal study, we extend this finding by looking at the pattern of language deterioration over time in the same population of Catalan-Spanish bilingual patients. All the participants completed three language-processing tasks (picture naming, word translation and word comprehension), both in their dominant (L1) and non-dominant (L2) language. At one year, the final group was made up of 50 patients: 15 with MCI and 35 with AD. For AD but not MCI, the language deterioration over time was the same in both languages, as previously reported in the cross-sectional study. The results are discussed in the frame of the hypothesis of shared lexico-semantic processing in highly proficient bilinguals and the influence of executive control deficits in language production.

Bilingualism in Primary Progressive Aphasia

“…The general pattern of language impairment does appear to agree with the shared bilingual neural substrate hypothesis, as at least at the whole-group level, as there was a tendency for parallel deterioration in both languages, in agreement with recent works on AD 9,27,28 . However, the results must be interpreted with caution given the methodological limitations of the study, particularly its limited sample size and lack of control over important linguistic mediating factors.…”

Ageing with bilingualism: benefits and challenges

“…For example, Manchon et al (2015) found that a group of 13 late proficient bilinguals with Alzheimer's type dementia were equally impaired relative to matched controls in both of their languages suggesting parallel decline. Gollan, Salmon, Montoya, & da Pena (2010) found the same pattern of parallel decline in balanced bilinguals (see also Calabria et al, 2017;Costa et al, 2012;and, for comprehension, Nanchen et al, 2017).…”

“…In their study, caregivers of a group of 51 people with dementia (of various types) reported decreased conversation in L2, a greater preference for the patients' original languages, intrusions from L1 into L2 conversational speech and asymmetrical language impairment with preferential preservation and use of L1. Many recent experimental cross-sectional studies have also found that the non-dominant language is more affected (see Calabria et al, 2017, Table 1).…”

AThEME: Advancing the European Multilingual Experience

“…Furthermore, Calabria et al (2017) investigate early and highly proficient bilinguals with Mild Cognitive Impairment (MCI) and with Alzheimer's disease (AD) in language production tasks, in particular, picture naming and word translation tasks. They followed the progression of bilingual individuals with MCI and AD for one year.…”