Bilingualism as a strategy to delay the onset of Alzheimer’s disease

Abstract

The purpose of this study is to explore original studies which provide evidence about the effects of bilingualism on the delay of the onset of dementia, specifically Alzheimer’s disease (AD). A literature review was conducted in the world’s acknowledged databases: Web of Science, Scopus, and MEDLINE. Altogether, 14 original studies focusing on the research topic were detected. These included six prospective cohort studies and eight retrospective studies. Both types of studies suggest different conclusions. The findings from the prospective cohort studies state that there is no association between bilingualism and the delay of the onset of AD, while the retrospective studies claim the opposite. Despite the negative results of the prospective cohort studies, more research should be conducted on bilingualism and its impact on the delay of the onset of AD, since the brain studies have brought positive findings as far as the enhancement of cognitive reserve is concerned.

Bilingualism Delays Expression of Alzheimer’s Clinical Syndrome

“…In 2007, Bialystok et al [13] reported that bilingual patients with probable AD were diagnosed about 4 years later than monolinguals with probable AD. Since then, investigators and most retrospective studies from around the world have suggested that bilingualism delays clinical symptoms of dementia by 4-5 years [3][4][5][6][7] (Table 4). In addition, pervasive multilingualism could be a factor in the low prevalence of cognitive complaints and dementia among older adults in Luxembourg [40], and, in the Lothian Birth Cohort (Scotland), those who learned a second language manifested better cognition in late life [41].…”

“…Elderly bilinguals, or those who can use two languages in everyday life and are at risk for AD, can clarify whether there is a "bilingual advantage" in the onset of dementia symptoms. Some, but not all, studies suggest that bilingualism promotes cognitive and neural resilience and delays the onset of the symptoms of dementia [3][4][5][6][7]. If learning or knowing a second language could postpone dementia symptoms even for a few years, this could mean major benefits, not only for quality of life in later years but also for decreasing related healthcare costs [8].…”

Organic Foods in Diets of Patients with Alzheimer’s Disease

“…The disease is progressive and its duration ranges from 8 to 20 years. As the disease advances, patients can lose their abilities of communication, suffer from urinary incontinence and require round-the-clock care [62,63].…”

“…In 2040, this number can even reach 81 million. Demographic tendencies show that an increase in the population of people over 65 years can be expected in this period, consequently leading to the increase in the number of cases of Alzheimer's disease [62,63].…”

Enhancement of posterior brain functional networks in bilingual older adults

“…Nevertheless, several studies have failed to identify such benefits among the bilingual population (Cox et al, 2016;Zahodne, Schofield, Farrell & Manly, 2014;Zatorre et al, 2001). In this regard, Klimova, Valis and Kuca (2017) concluded that, while prospective studies, in general, do not replicate the finding that bilinguals develop AD later in life, most retrospective studies come to that conclusion. Bilingualism is a complex skill, and differences in its conceptualization and measurement could be behind these discrepancies (Bialystok, 2017).…”