Multilingual Aphasia

Abstract

Multilingual aphasia is synonymous with polyglot aphasia and is often indistinguishable from bilingual aphasia. Multilingual aphasia, including bilingual aphasia, has been of interest from the perspectives of impairment and recovery patterns in each language, factors involved in recovery, and variations in cerebral lateralization of language function in each language. Early premorbid language proficiency and language use have been shown to play a crucial role in the manifestation of bilingual aphasia. Paradis (1989) classified the recovery pattern from bilingual aphasia into nine patterns and demonstrated that multiple variables, including age of language acquisition and language proficiency are involved in multiple dimensions. Previous studies on crossed aphasia have suggested the involvement of the right hemisphere in the cerebral lateralization of language function. However, a subsequent meta-analysis demonstrated that early bilingual individuals who acquired both languages by the age of 6 years had a bilateral organization of both languages. In contrast, late bilingual and monolingual individuals who acquired a second language after the age of 6 years had the lateralization of language function in the left hemisphere for both languages.