UOC investigates what type of bilingualism could prevent dementia

Speaking more than one language, especially in the case of people who use two languages daily, can represent a protective factor against the onset of dementia, according to some studies. However, bilingualism has many variables, for example the age of language acquisition, level of fluency, frequency of use, and it is not clear which of them represent an advantage when it comes to preventing or delaying the symptoms of this disease.

Research led by the Universitat Oberta de Catalunya (UOC) will study different types of bilingualism in Catalan and Spanish speakers and determine which of the variables are most beneficial for the brain. The project, entitled Bilingualism in disorders associated with ageing: from cognition to neural networks (BILiARD), will be led by Marco Calabria, member of the Faculty of Health Sciences and researcher at the NeuroAdaS Lab, with the collaboration of Laia Subirats, a researcher from the same group.

Speaking more than one language, especially in the case of people who use two languages daily, can represent a protective factor against the onset of dementia, according to some studies. However, bilingualism has many variables, for example the age of language acquisition, level of fluency, frequency of use, and it is not clear which of them represent an advantage when it comes to preventing or delaying the symptoms of this disease.

Research led by the Universitat Oberta de Catalunya (UOC) will study different types of bilingualism in Catalan and Spanish speakers and determine which of the variables are most beneficial for the brain. The project, entitled Bilingualism in disorders associated with ageing: from cognition to neural networks (BILiARD), will be led by Marco Calabria, member of the Faculty of Health Sciences and researcher at the NeuroAdaS Lab, with the collaboration of Laia Subirats, a researcher from the same group.

"Some studies have shown that speaking more than one language provides benefits that can delay the appearance of cognitive symptoms of dementia by up to four or five years. In our research we'll compare different types of bilingualism and, based on cognitive tests and neuroimaging data, we'll determine if there really are advantages, and in which areas", explained Calabria, who has a long history of studying the role of bilingualism in cognition and ageing.

The researchers will analyse a sample of data from 2,700 healthy individuals obtained from theALFA project, carried out by the Pasqual Maragall Foundation'sBarcelonaβeta Research Center. Most of the individuals, aged between 45 and 74, are children of Alzheimer's patients – the most common type of dementia. They were evaluated in terms of cognitive level, lifestyle habits, and using brain imaging techniques. Thirty-two per cent of the participants are carriers of the APOE4 genetic variant, which significantly increases the risk of developing the disease, and the researchers will analyse whether bilingualism also has beneficial effects in their case. The Barcelonaβeta Research Center monitored the carriers of this variant every three years from 2016 to 2022, so data are available on their evolution during this period.

ALFA study: a huge volume of high-value data

The researchers will work with two types of data: cognition data and neuroimaging data. They will analyse various aspects of bilingualism: how it influences memory and executive control; what impact it has on brain structure and metabolism; how it affects cognition and neuronal connections in dementia risk – especially in people carrying the APOE4 gene – and what changes there were in cognitive and brain reserve over time.

The cognition data collected in the ALFA study include domains such as memory, attention, executive functions and verbal fluency, which are parameters used in the diagnosis of cognitive impairment. Structural and functional (metabolism) neuroimaging data of brain activity will be used to study brain structure and the impact of bilingualism. In this part of the project, advanced data analysis techniques will be applied, including an innovative method used by the UOC called multilayer analysis, which allows different types of magnetic resonance imaging data (morphological, structural, and functional) to be connected and shown together. This method makes it possible to analyse really big data to detect subtle changes in the brain that it would otherwise not be possible to perceive. This multilayer analysis has been successfully used previously by the NeuroADas Lab with multiple sclerosis patients.

The main challenge in the analysis and interpretation of the results is the enormous complexity of the brain. In addition to studying its different areas, it is necessary to analyse the neural networks and the correlation of activities between areas: "Taking scientific results that show greater involvement of some brain areas than others and interpreting their significance in dementia prevention is a stimulating challenge, but not always an easy one", said Calabria.

The value of the Catalan case: an almost unique model of bilingualism 

For Calabria, one of the added values of the study is that "it'san opportunity to study a population with a linguistic experience that's almost unique in the world. In the field of bilingualism, there are few studies with large samples of participants. Thanks to the collaboration with the Barcelonaβeta Research Center, we have the opportunity to explore a sample of individuals with different bilingual profiles, and this will make it easier for us to identify which variables are most relevant when determining a cognitive and neural benefit. The social bilingualism that exists in Catalonia is found in few other countries in the world, with exceptions such as India or part of Canada."

The project will last three years and during that period work will be carried out to present the results at international conferences and during Brain Awareness Week. The final results will be announced in a workshop that will be organized by Universitat Oberta de Catalunya with the participation of international experts in the field.

Being able to confirm the benefits of bilingualism for cognition and brain efficiency will be a powerful tool to take into account in public health strategies for dementia prevention at a time when the prevalence of neurodegenerative diseases continues to rise in line with increasing life expectancy. "The message that will need to be delivered, therefore, is that speaking more than one language is beneficial as people get older and that this needs to be fostered from an early age," said Calabria.

This research contributes to UN Sustainable Development Goal (SDG) 3, Good health and well-being.

UOC R&I

The UOC's research and innovation (R&I) is helping overcome pressing challenges faced by global societies in the 21st century by studying interactions between technology and human & social sciences with a specific focus on the network society, e-learning and e-health.

Over 500 researchers and more than 50 research groups work in the UOC's seven faculties, its eLearning Research programme and its two research centres: the Internet Interdisciplinary Institute (IN3) and the eHealth Center (eHC).

The university also develops online learning innovations at its eLearning Innovation Center (eLinC), as well as UOC community entrepreneurship and knowledge transfer via the Hubbik platform.

Open knowledge and the goals of the United Nations 2030 Agenda for Sustainable Development serve as strategic pillars for the UOC's teaching, research and innovation. More information: research.uoc.edu.