Tag Archives: cognitive reserve

Education promotes cognitive reserve against dementia… but only if you’re white.

A headshot of a young woman smiling at the camera. She has brown hair and is wearing a black and white striped shirt.

Guest author: Justina Avila-Rieger, PhD is a postdoctoral fellow of Neuropsychology in Neurology at the Gertrude H. Sergievsky Center and the Taub Institute for Research in Aging and Alzheimer’s disease at Columbia University. She completed her graduate training in clinical psychology, with an emphasis on neuropsychology and quantitative methodology, at the University of New Mexico and completed her clinical internship at the Baltimore VAMC. Her research examines racial/ethnic and sex/gender disparities in Alzheimer’s disease.

Experts have long suggested that keeping your brain active, especially through continued education, is a great way to protect our brains against dementia as we age. The idea is that education allows our brain to build up a “cognitive reserve,” which acts as a buffer to slow the onset of dementia. However, our recent paper found that this advice may only apply to White people.

Cognitive reserve is the ability to maintain thinking abilities even if the brain is damaged. Many brain functions are flexible and can compensate or change to make added resources available to cope with challenges. The term cognitive reserve is used to describe this disconnect, when cognitive function is not as impaired as would be expected given the level of brain degeneration.1 In other words, for people with a high level of cognitive reserve, their brains can show severe signs of degeneration, yet their dementia symptoms are much milder than would be expected.

A chart with AD neuropathology on the x-axis and cognitive status on hte y-axis. A green line, indicating a person with high cognitive reserve, has higher cognitive status even in the presence of neuropathology. A yellow line, indicating a person with low cognitive reserve, has lower cognitive status with the same level of neuropathology. A horizontal red line indicates incident dementia, showing that the person with higher cognitive reserve does not develop dementia until their neuropathology is much more severe than the person with low cognitive reserve.
This figure illustrates the idea of cognitive reserve. People with high cognitive reserve can have severe Alzheimer’s disease (AD) neuropathology, yet not experience any cognitive symptoms. Image source

Some indicators of life experiences and contexts, including years of education, are often used as proxies for cognitive reserve because they are associated with lower dementia risk and delayed age of dementia onset.2 However, the majority of cognitive reserve studies have been conducted in predominantly non-Latinx White (White) samples and do not consider racial or ethnic differences in educational experiences. (Note: Latinx is the gender-neutral form of Latino/Latina and refers to people originating from Latin America.)

In our recent study, we tracked a community of 1,553 White, Black, and Caribbean-born Latinx  older adults over time.3 We found that White individuals with more years of education had slower cognitive decline compared with White individuals with fewer years of education, despite having the same level of brain degeneration. In other words, greater years of education buffered the effects of brain degeneration for White people. However, for Black and Latinx individuals, years of education did not protect cognitive function against the effects of brain degeneration.

Why might the protective effects of education differ across racial/ethnic groups? My colleagues and I suggest that racism is likely to be the primary underlying reason that having more years of school contributed to cognitive reserve in Whites, but not among Black or Latinx participants. Most Black older adults in the United States were born and raised in the South,4 where Jim Crow laws enforced segregation and limited opportunities within education, health care, housing, and the labor market.5 Across all U.S. states, both before and after Brown v. Board of Education, racist policies and residential segregation forced Black children to attend underfunded schools that had large student/teacher ratios, shorter term length, lower teacher salaries, and inadequate budgets for supplies and school buildings.6 These structural inequalities contribute to lower returns from education among Blacks compared to Whites.7

Similarly, older Caribbean-born Latinx who grew up outside of the United States also had fewer opportunities to attend school and/or received a poor quality of education.8,9 Years of education may not adequately represent the effect of life-course experiences that contribute to cognitive reserve across all racial/ethnic groups. As a result, the contribution of years of education to cognitive reserve is reduced for racial/ethnic minorities.

Even if educational experiences were equivalent across groups, structural racism impacts adult opportunities that might contribute to cognitive reserve across racial/ethnic groups. Racism in the labor market has served to counteract the benefits of schooling for Black Americans. For example, Black men continue to have lower employment rates than White men even if they have the same educational attainment10. It is also possible that the protective effects of education are reduced by stress associated with institutional racism and discrimination.

Do these findings mean that Black and Latinx individuals do not have cognitive reserve? Absolutely not. Rather, these findings suggest that years of education is just not a good indicator of the life-course experiences that contribute to cognitive reserve in Black and Latinx people. Several studies have demonstrated that measures of school quality may be a better indicator of educational experiences in racial/ethnic minorities than years of education.7–9,11,12 There is also evidence that early life educational policies13 influence later life dementia risk and cognitive decline, above and beyond educational attainment. There are also other early life experiences14 (e.g., childhood socioeconomic status, neighborhood factors) that may better indicators of cognitive reserve among Blacks and Latinx.

Overall, our findings provide more evidence that social inequalities across the lifecourse have an impact on racial and ethnic disparities in Alzheimer’s disease. Inequalities in school opportunities, including school segregation and limited governmental investment in schools that served Black and Latinx children, as well as racial discrimination in occupation, housing, criminal justice, and healthcare can help to explain why there are diminished “brain health” returns to educational attainment for Black and Latinx older adults. Considering that Black and Latinx individuals are 2 to 3 times more likely to develop Alzheimer’s disease than White individuals,15 more research is needed to understand the life-course factors that contribute to cognitive reserve. Such work may lead to identification of factors that may narrow racial/ethnic inequalities in the onset and progression of Alzheimer’s disease.

Sources:

  1. Mungas D, Gavett B, Fletcher E, Farias ST, DeCarli C, Reed B. Education amplifies brain atrophy effect on cognitive decline: Implications for cognitive reserve. Neurobiol Aging. 2018;68:142-150. doi:10.1016/j.neurobiolaging.2018.04.002
  2. Amieva H, Mokri H, Le Goff M, et al. Compensatory mechanisms in higher-educated subjects with Alzheimer’s disease: a study of 20 years of cognitive decline. Brain J Neurol. 2014;137(Pt 4):1167-1175. doi:10.1093/brain/awu035
  3. Avila JF, Arce Renteria M, Jones RN, et al. Education differentially contributes to cognitive reserve across racial/ethnic groups. Alzheimers Dement.
  4. Ruggles S, Sobek M, Alexander T. Integrated Public Use Microdata Series: Version 3.0. Minnesota Population Center; 2004.
  5. Barnes LL, Bennett DA. Alzheimer’s disease in African Americans: Risk factors and challenges for the future. Health Aff. 2014;33(4):580-586.
  6. Hedges LV, Laine RD, Greenwald R. Does Money Matter? A Meta-Analysis of Studies of the Effects of Differential School Inputs on Student Outcomes. Educ Res. 1994;23(3):5-14. doi:10.3102/0013189X023003005
  7. Manly JJ, Jacobs DM, Touradji P, Small SA, Stern Y. Reading level attenuates differences in neuropsychological test performance between African American and White elders. J Int Neupsychological Soc. 2002;8:341-348.
  8. Sisco S, Gross AL, Shih RA, et al. The role of early-life educational quality and literacy in explaining racial disparities in cognition in late life. J Gerontol B Psychol Sci Soc Sci. 2013;70(4):557-567.
  9. Manly JJ, Jacobs DM, Sano M, et al. Effect of literacy on neuropsychological test performance in nondemented, education-matched elders. J Int Neupsychological Soc. 1999;5:191-202.
  10. McDaniel A, DiPrete TA, Buchmann C, Shwed U. The black gender gap in educational attainment: historical trends and racial comparisons. Demography. 2011;48(3):889-914. doi:10.1007/s13524-011-0037-0
  11. Manly JJ, Byrd D, Touradji P, Sanchez D, Stern Y. Literacy and cognitive change among ethnically diverse elders. Int J Psychol. 2004;39(1):47-60.
  12. Arce Renteria M, Vonk JMJ, Felix G, et al. Illiteracy, dementia risk, and cognitive trajectories among older adults with low education. Neurology. 2019;93(24):2247-2256.
  13. Dementia risk likely measurable among adolescents, young adults. Accessed August 27, 2020. https://www.healio.com/news/psychiatry/20200730/dementia-risk-likely-measurable-among-adolescents-young-adults
  14. Xu H, Yang R, Qi X, et al. Association of Lifespan Cognitive Reserve Indicator With Dementia Risk in the Presence of Brain Pathologies. JAMA Neurol. Published online July 14, 2019. doi:10.1001/jamaneurol.2019.2455
  15. Facts and Figures. Alzheimer’s Disease and Dementia. Accessed August 27, 2020. https://www.alz.org/alzheimers-dementia/facts-figures

Note: This post was originally titled “Education protects against dementia… but only if you’re white.” This is inaccurate, and the title has been corrected accordingly.

Interview with a Dementia Researcher: Rory Boyle, Cognitive Neuroscience Researcher

What areas of research are you currently pursuing?

My PhD research is focused on using machine learning to identify markers of cognitive ageing. Currently, I am working on a project which uses machine learning and MRI scans to create a model of normal or healthy brain ageing. This model can be used to estimate how well, or poorly, a person’s brain is ageing and this estimation is termed the brain-predicted age difference, or brainPAD.

It has already been shown that people who have high brainPAD scores (which means their brains are ‘older’ relative to their actual age) have a higher risk of early mortality and tend to perform worse on measures of physical functioning (such as grip strength, lung function, walking speed).

However, we don’t yet know whether brainPAD can be used as a measure of cognitive ageing. If people with high brainPAD scores are shown to perform worse on tests of cognitive function, then brainPAD could potentially be used as a way of identifying such people at a very early stage, before cognitive decline is noticed using standard cognitive tests.

The next project in my PhD will look at developing an objective measure of cognitive reserve. Some people whose brains have the hallmarks of Alzheimer’s disease or other dementias seem to be able to maintain normal cognitive function. This has led researchers to try and understand why some people might have a buffer or some form of protection against certain neurodegenerative diseases. One theory is that people who are able to tolerate such neurodegeneration have high levels of what is called ‘cognitive reserve’.

Cognitive reserve refers to an individual’s ability to use their brain irrespective of their brains’ structural health. It is proposed that life experiences, such as education, occupational attainment, engagement in social, leisure, and mentally stimulating activities, and physical activity contribute to cognitive reserve.

However, currently, cognitive reserve is typically measured by questionnaires and interviews which measure these same factors (education, occupational attainment, etc.). This means that we might not have the most accurate measures, as people might not fully remember all the details of their education or social activities and their answers might be affected by response bias!

My goal is to use neuroimaging to develop an objective and standardised measure of cognitive reserve so that people with low cognitive reserve can be identified. This would allow for interventions to be directed at these people and it would also help in studies evaluating strategies to improve cognitive reserve.

What are the big questions or theories currently being debated in your subfield?

There are a couple of big questions which people are trying to answer in relation to cognitive reserve. Can cognitive reserve be objectively measured, and if so, how? What is the neural basis of cognitive reserve? Hopefully my project will help to shed some light on these questions.

What is a common misconception related to dementia that you often encounter?

One common misconception is that there nothing we can do to reduce our risk of dementia. Given our knowledge of cognitive reserve, one way we could reduce our risk of dementia is by increasing cognitive reserve! There is more and more evidence that taking part in mentally stimulating activities, being socially active, and regularly exercising can lower the risk of dementia. More generally, there is evidence that having a healthy diet, particularly a Mediterranean diet, not smoking, and cutting down on alcohol can also reduce the risk of dementia.

What recommendations would you give to people wanting to reduce their risk of Alzheimer’s disease?

Like a lot of things, the best recommendations for reducing risk of Alzheimer’s disease or other dementias are to live a healthy and active life. Specifically, try to exercise three times a week, particularly aerobic exercise like brisk walking, swimming, cycling. As well as that, try to stick to a Mediterranean diet, which is rich in fruits and vegetables, whole grains, beans and nuts, olive oil and fish.

Be socially active, join a group or club. In Ireland, we have a really great initiative called Men’s Sheds were men can meet up and work together on hobbies and meaningful projects. This is a great example of how people can keep socially engaged. As well as that, take part in mentally stimulating activities like puzzles and Sudoku. If you have access to a PC, there are now thousands of free online courses on websites like Coursera or EdX. By signing up for these, you can challenge yourself and learn something new, all while keeping your brain stimulated!

How can non-scientists contribute to the fight against Alzheimer’s?

Non-scientists could help in the fight against Alzheimer’s by taking part in research. Research studies are always on the lookout for participants. People without Alzheimer’s disease are always needed as well to form control groups. Have a look online or at any nearby universities!

On top of that, there are now even easier ways to take part in research. For example, downloading and playing the SeaHero Quest app allows researchers to collect valuable information about how the brain navigates in space, which is a key skill that declines early on in dementia.

When do you believe a viable Alzheimer’s treatment will be available?

I’m not sure, but I am hopeful that with all of the new techniques we will be able to identify people likely to develop Alzheimer’s or other dementias, earlier than ever before. This will allow for any interventions that can help with Alzheimer’s to be implemented at the early stages of the disease, where interventions are likely to be most specific. It will also help researchers test and monitor the effects of new interventions and treatments.

Is there any other information you’d like to add?

My PhD research is funded by the Irish Research Council, in partnership with Altoida AG. I am very grateful for the support of both of these organisations. Altoida AG has developed an app that uses computerised and gamefied tests of cognitive performance to evaluate perceptual and memory function in older adults. This app may ultimately allow for early screening of mild cognitive impairment and identification of people who are at risk of developing Alzheimer’s disease. We have tested this app on a number of older adults here in Trinity College, and hopefully we will have some interesting data from these tests in the next year!

 

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Rory Boyle is a PhD candidate in the Whelan Lab in Trinity College Dublin. He graduated with a BSc in Psychology from Dublin City University in 2014, and an MSc in Brain Sciences from the University of Glasgow in 2016. His BSc research project compared the effects of aerobic exercise and caffeine consumption on measures of mood and cognitive performance. His MSc research project used EEG to investigate the age-related differences in the visual processing of faces. Specifically, his project examined whether there were differences in the information content of brain activity during the visual processing of faces.

 

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Do Brain-Training Games Really Prevent Alzheimer’s?

In January 2016, Luminosity was forced to pay $2 million dollars after being sued for false advertising. Ads for the popular “brain-training” game suggested that the mental exercises could improve cognition and even reduce the effects of dementia. However, these claims have not stood up to scientific examination. In this article I’ll break down the science of neuroplasticity that brain-training games are based on, review the evidence of their inefficacy, and finally provide a few scientifically valid alternatives to brain games.

The Plastic Brain

What exactly is the “science of neuroplasticity” that ads for Lumunosity and other brain-training games keep talking about? In this context, plastic means changeable. Thus, the field of neuroplasticity examines the ways our brains can change over time. For much of the history of neuroscience, it was believed that only infants and children had plastic brains. The popular theory was that children’s brains were in a critical period of rapid change that allowed them to quickly learn new things such as language. This critical period was thought to end around the age of five, at which point our brain structure would remain static for the rest of our lives.

However, within the past few decades, evidence has emerged to suggest that the adult brain is also plastic, albeit to a lesser extent than children’s brains. You may have heard stories of blind people who possess a seemingly-superhuman sense of hearing. These are more than just anecdotes. Multiple studies have demonstrated this phenomenon to be true, even when vision loss occurs during adulthood. The brain space that had once been devoted to vision is taken over by the other senses. Similarly, many adults are able to partially recover from neurological injuries such as a stroke or traumatic brain injury by utilizing their brains’ capacity for change, creating new neural connections to make up for those that were damaged.

A simple dogma has emerged from studies of adult neuroplasticity: “neurons that fire together, wire together.” This basically means that the more a particular neural circuit is activated, the stronger the connections between those neurons become. It’s kind of as if your brain were a muscle, and activating neural pathways were like a “workout” for your brain. This is a bit of an oversimplification, but it illustrates the fact that we tend to become better at cognitive tasks the more we practice them. These improvements correspond to physical changes that occur inside our brains, just like a muscle growing larger and stronger.

This is the basis for brain-training games like Luminosity. Based on what we currently know about neuroplasticity, it makes sense that playing games that involve memory, logic, or problem-solving should improve the relevant neural circuits and result in better cognitive function overall. So then, what’s the problem?

Why Brain-Training Games Don’t Work

Let’s say you’re playing a card-matching game that’s designed to improve memory. Each game is randomly-generated so the cards are never in the same spots each time. The first time you play, it might take you five minutes to complete the puzzle. The next time, you’re a little faster. You play this game every day for a month. By the end of the month, you can complete the task in half your original time. It’s reasonable to think that your memory is now far better compared to when you first played the game.

However, just because you’re better at this particular game doesn’t mean that your overall memory has improved. To date there has been little evidence that playing these games can improve practical memory skills such as remembering where you left your keys or recalling a friend’s phone number. In fact, cognitive improvements due to brain-training games are often very narrow in scope, only applying tasks that are very similar to the game itself. Additionally, while some studies have suggested that these gains are lasting, others report that the effects of brain training dissipate over time. Most importantly, there has been zero evidence to suggest that these games can reduce the risk or symptoms of Alzheimer’s or other dementias.

The problems with brain-training games were highlighted in a consensus report published in 2014. The report was signed by 70 experts in cognitive science, neuroscience, and gerontology. It argued that advertisements promising broad cognitive enhancement by brain-training games were highly exaggerated and lacked solid scientific support.

So, Now What?

You might be thinking: okay, maybe these games aren’t the magic dementia cure they claim to be, but surely there’s no harm in playing them? After all, it’s likely that these games do produce some small improvement to cognitive function, albeit narrow and probably temporary. But if there’s even a small chance of making our brains healthier, shouldn’t we take it?

The question here isn’t whether brain-training games produce any beneficial effects, but whether the beneficial outweigh the opportunity cost. This was a key point of the consensus report that I mentioned earlier:

“Time spent playing the games is time not spent reading, socializing, gardening, exercising, or engaging in many other activities that may benefit cognitive and physical health of older adults.”

So it’s not that brain-training games do nothing for cognition, but that their effects are minuscule compared to other scientifically-validated approaches for reducing the risk of dementia. These include incorporating more fruits and vegetables into your diet, maintaining an active social life, and keeping your mind active through a variety of intellectually stimulating tasks. Check out the Alzheimer’s Association’s brain health website for some great tips on reducing your risk for dementia.

When presented with the choice of improving our brain health through fun activities like socializing with friends, gardening, or learning a new language, compared to doing so through a series of monotonous computer games, to me the choice seems obvious. If you want your brain to be healthier, why not make the process enjoyable too?

 

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