Language assessment and therapy for verb-production impairments in multilingual aphasia

Abstract

Aphasia is an acquired language disorder induced by a focal damage to the brain, most commonly caused by a stroke. For all speakers with aphasia word retrieval is difficult, and in particular verbs are challenging. At the same time verbs play a crucial role in communication. Hence, verb retrieval impairments potentially have profound implications on everyday interaction. In multilingual speakers with aphasia, the different languages can be differently affected. Thus, assessment and treatment may be even more challenging than with monolingual speakers. The dissertation, which is the first one on multilingual aphasia in Norway, investigates assessment, clinical practice and treatment, with a focus on cross-linguistic transfer and inhibition of the untreated languages. The results are analysed in light of different models of multilingual language processing. The dissertation shows the importance of assessing all the languages of multilingual speakers with aphasia and of complementing formal assessments with functional assessment tools. It contributes new knowledge on the impact of verb-production treatments for speakers with different aphasia types. The dissertation shows that treatment in one language has positive effects, not only in the treated language, but also in the other, untreated language(s) of the speaker. Importantly, treatment in one language does not harm the other language(s). Furthermore, treatments focusing on production of verbs in sentence contexts result in improvement in discourse production. Finally, the dissertation shows that treatment gains are attainable when treatment is provided in a non-native language of both the client and the clinician. The results corroborate theories on the nature of the verb and its role in sentence production, and provide evidence for a shared conceptual network of the languages in multilingual speakers. With its clinical focus and firm theoretical basis, the dissertation has inter- and multidisciplinary relevance.