The advantageous impact of learning multiple languages is one of the most consistent pillars of neurolinguistics.

The research literature suggests that doing so early in life contributes to improved executive function, emotional intelligence, and even disease prevention, namely Huntington’s disease and Parkinson’s.

A new study published in Neuropsychologia more directly states that those who actively speak more than one language are less likely to suffer from cognitive impairment associated with aging compared to those who do not. The former appears to additionally enjoy boosts to their cognitive reserve.

The cognitive reserve is a measure of one’s resistance to cellular damage. This can be analyzed via behavioral markers alongside histological data (biological tissue).

This development will help physicians detect dementia during its preclinical phase so that patients can receive the best treatment before the condition inflicts irreversible harm.

“Lifelong bilingualism may contribute to cognitive reserve (CR) in neurodegenerative diseases as shown by a delay of the age at symptom onset in bilinguals with Alzheimer’s disease (AD) and Mild Cognitive Impairment (MCI),” the authors wrote in the new paper. “However, some studies have failed to show this bilingual advantage, suggesting that it might depend on the type and degree of bilingualism. In the present study, we tested the hypothesis that active bilingualism, defined as the continuous use of the two languages as opposed to second language exposition only, may protect against cognitive decline. Moreover, we investigated whether bilingualism as a CR factor may be explained by an advantage within the executive control (EC) system.”

Active bilingualism delays the onset of dementia

In order to ascertain each participant’s degree of bilingualism, the authors had them complete a language questionnaire.

A portion of the study pool is passively bilingual, meaning they primarily speak one language but are frequently exposed to another. While the remaining could proficiently oscillate between two different languages on a daily basis without verbal intrusions. Similarly, some of the participants were previously diagnosed with mild cognitive impairment while others expressed more severe manifestations.

The researchers subsequently paired responses with the age of neurological diagnosis and the appearance of instructive symptoms.

In a followup review, it was revealed that respondents who exhibited a higher degree of bilingualism concurrently developed mild forms of neurodegenerative illness, compared to passive bilinguals.

In countries where the majority of the population is bilingual, dementia is 50% less common than in regions where citizens only speak one language.

The mechanisms, at least in part, seemed to correspond with the degree of mental fortitude it takes to habitually alternate between different languages. Over time, this routine multi-tasking strengthens the cognitive reserve, executive function, and delays dementia complications.

It should be noted that bilingualism was not as influential with respect to aggressive presentations of impaired cognitive function.

“Results from multiple regression analyses showed that active bilingualism was a significant predictor of delay in the age at onset for all the clinical measures in MCI, but not AD patients. Second, the effect of active bilingualism was independent of occupation, educational level, and job attainment across the individuals’ lifespan” the author concluded. “Finally, although we did not find an effect of active bilingualism across all EC tasks, we did find an effect for conflict resolution. These results are discussed in the context of CR hypotheses, suggesting that compensatory mechanisms may play a role in protecting against cognitive decline.”