Bilingual Aphasia with Parallel Recovery

Bilingualism has been commonly used in scientific and common nomenclature to refer to the knowledge and/or use of two languages, though the specifics of the definition have been widely debated (e.g. Altarriba & Heredia, 2008; De Groot & Kroll, 1997; Grosjean, 2010). In fact, one half (Grosjean, 2010) to two-thirds (Walraff, 2000) of all people in the world have been estimated to routinely use more than one language in everyday communicative contexts. Given this global linguistic profile, it has been suggested that an increasing number of people with communication difficulties post-brain injury are likely to be bilingual (Ansaldo, Marchotte, Scherer, & Raboyeau, 2008; Centeno, 2009). Bilingual aphasia refers to difficulties in comprehension and/or production of language in one or more modalities in the presence of intact intellect, observed in speakers of two or more languages. The projected incidence of bilingual aphasia is at least 45,000 new cases per year in just the United States (Paradis, 2001).

One of the most fascinating aspects of bilingualism is the ability of bilingual speakers (particularly those with high proficiency in their constituent languages) to effectively communicate in one language without interference from the non-target language. The cognitive process underlying this ability is often referred to as cross-language control (e.g., Green, 1998; Calabria, Hernandez, Branzi & Costa, in press; Costa and Santesteban, 2004; Crinion et al., 2006; Abutalebi and Green, 2007). External cues such as language environment and linguistic knowledge of the communicative partner have been found to impose some constraints on non-target language interference (e.g., Hoshino & Kroll, 2008). But the underlying cognitive-linguisti...

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...and Sabatini (2009) also report the absence of any language switching errors in a highly proficient bilingual who recovered both languages equally post-stroke. Similar findings have also been reported in English-Japanese (Watamori & Sasanuma, 1978), Mandarin-English (McCann, Lee, Purdy and Paulin, in press) and German-English-Spanish (Green et al., 2011) highly proficient speakers with parallel recovery using language assessments and conversational speech tasks.

Taken together, these findings indicate that evidence for cross-language control failure in bilingual aphasia with parallel recovery is inconclusive at best. Given that cross-language control is not always impaired in individuals with parallel recovery of bilingual aphasia, it is not clear what role, if any, impaired cross-linguistic control plays in lexical retrieval failure in this clinical population.