Implications of bilingualism for neuropsychological evaluation: Insights from a multicentric study from India

Abstract

AbstractBackgroundIn the background of linguistic diversity and a large population of bilinguals in India, it is essential to develop standards of neuropsychological testing in the context of bilingualism. Since bilingualism is known to impact specific cognitive processes, there is also the possibility of the need for separate normative data for bilinguals and monolinguals. Towards addressing these gaps, in this large multicentric study from India, bilinguals and monolinguals were evaluated on a comprehensive neuropsychological test battery: the Indian Council of Medical Research‐Neuro Cognitive Tool Box (ICMR‐NCTB).MethodThe ICMR‐NCTB that was standardized across five Indian languages was administered to 530 participants: 267 monolingual and 263 bilinguals A systematic method of testing cognition in bilinguals was developed, to identify the appropriate language for testing, ensure language proficiency of examiner, and to interpret the bilingual responses. Additionally, the performance of bilinguals on the ICMR‐NCTB was compared with monolinguals matched for age, education, and gender.ResultLinguistic proficiency of both participants and examiners were determined using validated measures. Cognitive testing in the bilingual context was performed in the most proficient language of the participants, by examiners well versed with the language. Results from the language‐based tests suggested language interference i.e. a frequent occurrence of borrowed‐ and language‐mixed words in responses thereby requiring consideration while scoring. The reported bilingual effect on cognitive processes did not reflect as differences in the performance between bilinguals and monolinguals on any of the standard cognitive tests of attention, executive function, language and visuospatial functions.ConclusionObservations from the study provide robust recommendations for neuropsychological testing in the context of bilingualism. These recommendations are consistent with the practice of bilingualism in the Indian context and are more ecologically valid. Results also indicate that separate normative data may not be required for bilinguals and monolinguals, in the Indian context. The study will provide a reference framework for comparison to address similar issues in other bilingual societies.