Background:Rehabilitation of language disorders in bilinguals is arelatively new field of research, with few studies concerned with the treatment of acquired aphasia in bilingual people having been reported, particularly with respect to the treatment of dysgraphia. Capitalising on successful approaches to diagnosis and treatment of aphasia in both monolinguals and bilinguals, this thesis investigates the effectiveness of model-based therapy following damage to language processing in Welsh-English bilingual individuals. It contributes to discovering the most effective approaches to rehabilitation in bilingual aphasia and informs theories of bilingual language processing.
Objectives: 1) To discover whether cross-linguistic treatment generalisation may occur in Welsh-English bilingual aphasia; 2) To explore generalisation as a function of deficit type, language of treatment, and stimuli used; 3) To inform theories of bilingual word processing using patterns of treatment generalisation.Methods:Bilingual individuals with aphasia took part in studies of model-based language rehabilitation. A phonemic cueing treatment targeting severe anomia, a delayed-copy spelling protocol targeting lexical and graphemic buffer deficits, and a sublexical spelling therapy are described. It was hypothesised that all participants would show treatment-specific gains, and predictions regarding within and between-language generalisation varied according to the language and type of therapy, and the nature of the deficit.
Results:As predicted, within-language improvement in untreated items was observed in all participants. Between-language effects varied according to deficit: cross-language generalisation was observed in treatment of phonological output (cognates only), graphemic buffer, and sublexical deficits.
Conclusions: This is the first research exploring Welsh-English bilingual aphasia therapy, and also includes the first studies of bilingual dysgraphia therapy. It supports previous research in both monolinguals and bilinguals, regarding benefits of therapy to different deficits, but also provides new evidence that cross-language treatment generalisation can occur in bilingual dysgraphia. It also contributes toward developing theories of bilingual language processing, particularly in terms of spelling.