Brazilian Literacy Program Improves Executive Function in Low-Educated Population, Reducing Dementia Risk
Improvements were observed in both the intervention and control group, with those who had self-reported learning difficulties showing the least improvement.
Image credit: AnnaStills | stock.adobe.com
A literacy program in Brazil positively impacted executive function in low-educated participants at a risk for dementia or Alzheimer disease, explained Clarisse Vasconcelos Friedlaender, a PhD candidate, neuropsychologist, and researcher at Universidade Federal de Minas Gerais, Belo Horizonte, Brazil, during a featured research session at the 2024 Alzheimer’s Association International Conference (AAIC), which was held in Philadelphia, Pennsylvania. The findings were particularly encouraging, noted Friedlaender, because those with lower initial executive function levels had also experienced greater improvements following participation in the literacy program.1
At the beginning of the presentation, Friedlaender explained that the prevalence of dementia in Latin America is twice as high in those who are considered illiterate, and according to a 2022 study, the incidence is 5 times higher in Brazil.1 Prior research had demonstrated that early-life education is a well-established risk factor for the prevention of dementia,2 and in order to properly boost cognitive reserve and reduce the risk of dementia within vulnerable populations in Brazil, Friedlaender and her fellow researchers created a literacy program that specifically targets adults who have limited schooling. Their study analyzed how executive function and cognitive heterogeneity may interfere in the efficacy of their literacy and memory program: Programa de Alfabetização e Memória (PROAME).1
“These populations are comprised of individuals who don't know how to write or how to read, so they really didn't go to school up until that point in their lives when we recruited them for our study,” said Friedlaender during the AAIC presentation. “This is a special condition that is hard to explain sometimes to people who don't come from low- and middle-income countries. Sometimes I get the feeling that [some individuals] don't believe that they don't know how to write and how to read, so this is important to stress here.”1
PROAME was created to assess whether literacy training—even if it is later in life—can improve cognitive reserve and therefore lower the risk of dementia in this population. A total of 130 individuals enrolled, but 108 met eligibility for the program. Of these 108 participants, 77 completed all procedures (control group: n = 26; intervention group: n = 36; and those who failed to complete all executive function tasks: n = 15).1,2
Participants in the control group attended regular classes that taught Portuguese, math, geography, history, and sciences, whereas those in the intervention group attended regular classes that were specifically focused on improving participants’ reading and writing skills. To assess the efficacy of the program, subjects underwent a comprehensive neuropsychological assessment that covered global cognition, executive function, memory, and language at baseline and after 6 months. At these 2 screenings, MRIs and blood sample (NFL) tests were also conducted.1,2
Of the total enrolled population (N = 108), the majority of participants were women (71.3%) and Black (57%), with a mean age and education level of 58.4 ± 7.9 and 1.9 ± 2.1, respectively. Additionally, approximately 91% of participants were of a low socioeconomic status.2 Friedlaender also noted that the most frequent self-reported reason for illiteracy was dropping out of school as a child to support family (41.2%), with other reasons being growing up in rural areas (24.7%), lack of family support (17.6%), and learning difficulties (16.6%).1,2
According to the findings, the researchers observed that the baseline executive function composite score was significantly correlated with the functional connectivity of the frontoparietal network. There was also an observed improvement in the connectivity between the left frontal pole and the precuneus cortex, with the improvement being significantly higher in the intervention group compared with the control group. Friedlaender also emphasized that there were different executive function improvements according to the self-reported reason for illiteracy during childhood; however, a poor executive performance at baseline was correlated with a greater change in executive function after intervention, regardless of the group participants were placed in.1,2
“The first thing we saw is that the sessions in literacy training were only effective if they were combined with attendance in adult education courses. We also could see that the self-reported reason for illiteracy in childhood influenced how much one could benefit from the intervention,” said Friedlaender. “[For example,] the group who reported living in rural areas showed a greater executive function improvement, and the group who told us they had learning disabilities [as the reason] they left school when they were children had less improvements in executive function.”1
Those who had a reported learning disability showed a poorer performance on a composite score of baseline tasks to assess executive function (F = 3.814, p = 0.021). Additionally, executive function levels at baseline correlated with reading abilities both at baseline (Spearman’s rho = 0.659, p < .001) and follow-up (Spearman’s rho = 0.703, p < .001). The researchers speculated that the observation of poor executive function and little improvement in this subpopulation may indicate potential undiagnosed neurodevelopmental disorders, such as dyslexia or attention deficit hyperactivity disorder, and may still be uncared for. In this subpopulation, there is a greater risk of developing dementia, according to the investigators.2
Further, serum NFL levels at baseline were positively correlated with age (n = 74). These individuals were more sensitive to the intervention, suggesting a need to implement prevention strategies earlier.2
Friedlaender stressed that with literacy and memory programs such as PROAME, it is important to implement them into communities immediately so older adults can benefit from them as much as possible. Additionally, she said that individual differences, such as personality traits and social and economic backgrounds, should be considered to effectively design specific interventions that are adapted to the population.1,2
“I like to think of executive function as a bridge that enables our relationship with the environment, so it's very important that we take good care of this cognitive function, and a very good way to do so is through incentive to promote [this] training in our vulnerable populations and prevent cognitive decline and dementia,” said Friedlaender.1
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