Bilingualism in the ageing population: consequences of language change and language loss in bilingual dementia and aphasia

Bilingualism is prevalent and increasing in Australia, particularly in the ageing population. Over 30% of individuals aged 65 and older speak a language other than English (ABS, 2006). Older individuals are at higher risk of language and communication impairment due to strokes and dementia. Communication and language impairment impact on the individual's independence, daily functioning and psychosocial wellbeing, and on carer stress. For bilingual adults, the extent, type and time-course of impairment often presents differently in each language (Paradis 2008). Accurate diagnosis and management is dependent on thorough assessment in each language, yet detailed cognitive and communicative assessment often continues to be conducted in English only. Given the increasing bilingual aged population, it is important that practitioners and service providers are aware of the impact of communication impairment in bilinguals, and the need for assessment in both languages. This research describes patterns of language change in bilinguals with acquired language impairment (aphasia) and dementia, and the impact on social interaction and independent functioning. Research findings from a recent empirical study show that bilingual individuals previously able to fluently speak English and a community language (Rarotongan Cook Islands Maori, Maltese, French) were impaired in each language and impaired in their ability to switch languages in conversation, a typical part of everyday interaction. Impaired communication skill in each language impacted on their ability to participate in daily community activities (e.g. shopping) and to function independently at home (e.g. use the telephone for social or emergency purposes), and impacted on quality of life and wellbeing for both the individual and carer. The implications of this study and recommendations for future care and management of bilingual aged population with communication impairments are discussed.