Aphasia in Bilinguals

Summary

The neurophysiological and the neurolinguistic basis of multilingualism is not yet fully elucidated. A study of the occurrence of aphasia in multilingual patients and the pattern of recovery may help to clarify some unsolved problems. For e.g. is the ability to use a second language stored in a different area of the left hemisphere and what is the extent of involvement of the right hemisphere in language skills? When recovery from aphasia occurs, what factors determine the rate of recovery of different languages and the priorities of recovery?

To understand some of the problems, a study of aphasia in multilinguals was conducted in Madras, South India, where multilingualism is common. 88 patients were studied with 40 healthy controls, using standard protocols. It was found that the pattern of recovery was dispersed widely in time, rate, level, degree and between the languages known. No support was obtained for the notion that the patients’ mother tongue recovers first, nor was support found for the importance of language proficiency viewed globally. Evidence was found that the languages in which routine thinking, mental calculations and praying were carried out were the ones most resistant to damage in brain insults. It is interesting that these functions are all highly overlearned, acquired early in life and used frequently over the course of many years.

Another observation made was that the incidence of crossed aphasia was fairly high, in both uni- and multi-linguals, with the latter showing a slightly higher incidence. The more than expected higher incidence of crossed aphasia in unilinguals suggests that the language capacities of the right hemisphere in unilinguals may have been underestimated in earlier literature.

There are many aspects of language function in multilingual aphasics which have to be elucidated and further extensive neurolinguistic research is necessary, before positive conclusions can be arrived at.