Can foreign language learning boost cognitive flexibility in late-life depression?

Background
Given that life expectancy has been increasing, finding ways to promote healthy aging is crucial. Late-Life Depression (LLD) is a highly-prevalent threat to healthy aging, as it interferes with normal cognitive functioning and quality of life. LLD has been consistently linked to impairments in, for example, cognitive flexibility and memory, leading to theories that LLD is a prodromal form of dementia. While the cause of LLD is still being debated, known risk factors are lack of social contact and low cognitive reserve, i.e., the ability to cope with age-related and pathological brain changes. Interestingly, lifelong bilingualism has been proposed to build up cognitive reserve, and some studies found it delays the onset of dementia symptoms. In fact, the cognitive domains negatively affected in LLD overlap considerably with those boosted through bilingualism, such as cognitive flexibility, attention, and working memory.

Objective
This study investigates whether the introduction of a bilingual experience later in life, in the form of a foreign language course, can boost cognitive functioning and well-being in seniors with and without LLD. Recent evidence suggests that acquiring new skills in later life, such as proficiency in a new language, may boost confidence and well-being as well as cognitive functioning. This may be further increased by the inherently social nature of language use.

Design/method
The effects of foreign language learning in healthy seniors and those with LLD are measured using a (neuro)psychological test battery focusing on cognitive flexibility and well-being. To assess how language learning’s effects differ from other cognitively stimulating activities, nondepressed seniors from the language condition will be compared to other neurotypical seniors who took music lessons or attended a lecture series.

Hypotheses
While all participants may benefit from the language course, the LLD group is expected to show greater improvements in cognitive flexibility and well-being than the non-LLD group. Also, by introducing between-language competition and facilitating communication, language learning stimulates cognitive flexibility and interpersonal relationships distinctly from the other courses. Language learners are therefore expected to outperform the other two groups. If this is indeed the case, foreign language learning could be explored as a tool to prevent and/or treat LLD.