So how can we prevent dementia?
There are many risk factors and protective factors against dementia. Risk factors such as age, excessive use of alcohol, poor diet, high blood pressure, high blood glucose and cholesterol levels, high body mass index (BMI), inactivity, depression, social isolation, low educational attainment, brain injury, and family history of dementia to name a few (Centres for Disease and Prevention (CDC), 2019; World Health Organization (WHO), 2021). Protective factors are those that can help prevent dementia such as being physically, mentally, and socially active, healthy BMI, and healthy diet (think Canada food guide) (WHO, 2021; Anderson et al., 2020, p. 953). For physical activity, the Canadian Society for Exercise Physiology (2021) recommends at least 150 minutes of moderate to vigorous aerobic physical activity in a week coupled with muscle strengthening.
One area that is of particular interest for me is how speaking a second language can help delay the symptoms of dementia (Anderson et al., 2020, p. 953). Many studies have suggested that being bilingual can delay the onset of symptoms on average by 4-4.5 years compared to monolinguals (Perani et al., 2017, p.1690; Anderson et al., 2020, p. 953). A bilingual is somebody who speaks two languages; and a monolingual is somebody who only speaks one language (Klimova et al., 2017, p. 1732). Why do bilinguals have this advantage? This could be due to cognitive reserves allowing the brain to compensate for areas that are degenerating due to the disease (Klimova et al, 2017, p. 1732; Perani et al., 2017, p. 1690; Anderson et al., 2020, p. 953).
This cognitive reserve is also “defined as the resilience to neuropathological damage of the brain” (Klimova et al, 2017; p. 1732). It allows the brain to reorganize itself and allow other parts to take over which is why bilingual individuals do not exhibit symptoms of dementia until roughly 4 years after initial diagnosis (Kilmova et al., 2017, p. 1732; Perani et al., 2017, p. 1682). It is believed that due to the brain having to switch between different languages, each language with their own rules and structures, has made the brain flexible and more efficient (more synapsing of neurons) (Anderson et al., 2020, p. 962; Kilmova et al., 2017, p. 1732). The switching between languages allows the brain to reroute when it is damage hence the delay of observable symptoms in bilinguals (Anderson et al., 2020, p. 962).
From Canva. (2022, February 24). Untitled.
However, there have been studies that have shown no difference in the development of dementia when observing bilingual and monolingual individuals (Klimova et al., 2017, p. 1734). They have found no advantage and have noted those other studies often used immigrants which most likely already have a higher attainment of education contributing to cognitive reserves (Klimova et al., 2017, p. 1734). Although most of the studies include immigrants, there have been studies done with individuals who are bilingual and non-immigrants producing this advantage (Anderson et al., 2020, p. 953). This indicates that more research in this field is needed to further solidify the advantage or lack thereof.
References
Anderson, J.A.E., Hawrylewicz, K., Grundy, J.G. (2020). Does bilingualism protect against dementia? A meta-analysis. Psychonomic bulletin & review, 27, 952-965. https://doi.org/10.3758/s13423-020-01736-5
Canadian Society for Exercise Physiology. (2021). Canadian 24-hour movement guidelines: An integration of physical activity, sedentary behaviour, and sleep. https://csepguidelines.ca/
Canva. (n.d.). https://www.canva.com/
Centres for Disease Control and Prevention. (2019, April 5). What is Dementia? Alzheimer’s disease and healthy aging. https://www.cdc.gov/aging/dementia/index.html#:~:text=Dementia%20is%20not%20a%20specific,a%20part%20of%20normal%20aging.
Klimova, B., Valis, M., Kuca, K. (2017). Bilingualism as a strategy to delay the onset of Alzheimer’s disease. Clinical interventions in aging, 12, 1721-1737. https://doi.org/10.2147/CIA.S145397.
Perani, D., Farsad, M., Ballarini, T., Lubian, F., Malpetti, M., Fracchetti, A., Magnani, G., March, A., Abutalebi, J. (2017). The impact of bilingualism on brain reserve and metabolic connectivity in Alzheimer’s demntia. Proceedings of the national academy of sciences of the united states of America, 114I(7), 1690-1695. https://doi.org/10.1073/pnas.1610909114
World Health Organization. (2021, September 2). Dementia. https://www.who.int/news-room/fact-sheets/detail/dementia