To date, several studies have shown the relationship between the prefrontal cerebral cortex and some subcortical structures and the skills that bilingual people present to change language or to use one of the languages, without the other language interfering. These same areas are involved in the mechanisms controlling task switching, i.e. all the skills that oversee our actions as we move from one task to another.

According to Albert Costa, "this suggests that there is a close relationship between the general mechanisms in cognitive control, and those used by bilingual people to control the two languages."

A paper published in the advanced online edition of the journal Neuropsychologia which was coordinated by Albert Costa, ICREA researcher at the DTIC and head of the research group on Language Production and Bilingualism (SPB) at the Center of Brain and Cognition at UPF, has studied how an illness may affect cognitive control mechanisms.

More specifically, the researchers focused on a degenerative condition of the central nervous system, Parkinson's disease, which affects precisely the same brain structures with the consequent loss of control skills.

"We thought that studying the extent to which the control of languages is affected in these patients would tell us about its relationship with general cognitive control," said Albert Costa, coordinator of the study.

To carry out the study, Costa and his team studied how people affected by Parkinson's disease perform language control and general executive control, in comparison with healthy individuals.

The results obtained suggest that Parkinson's disease, from its earliest stages, affects the ability to manage languages, hindering changes and the management of the interference of the language not being used.

These results provide interesting evidence about the role of some subcortical structures in the production of language, and in the ability to control two languages in cases of bilingualism.  At the same time, it also shows that only some general cognitive control deficits are related to the loss of control of skills in both languages. Specifically, these are the more sustained control mechanisms that enable bilingual people to control both languages when speaking.

For further reference, see:

Gabriele Cattaneo, Marco Calabria, Paula Marne, Alexandre Gironell, Jubin Abutalebi, Albert Costa (2014), " The role of executive control in bilingual language production: A study with Parkinson's disease individuals", Neuropsychologia, volum 66, January 2015, pp. 99-110. doi:10.1016/j.neuropsychologia.2014.11.006.