Abstract
<jats:p>Background: Dementia is a progressive neurodegenerative disorder characterized by cognitive decline and its incidence in Brazil is 5 times higher in illiterates. Early life education is a well-established modifiable risk factor for dementia prevention. However, whether learning to read and write in adulthood contributes to brain health is still unknown. Objective: To elucidate the effects of a late-life literacy intervention on cognitive reserve and brain connectivity in illiterate adults. We conducted a longitudinal clinical trial within an adult-literacy program targeting low-educated adults which is called PROAME (“Programa de Alfabetização e Memória”) Methods: First, 130 illiterate adults were screened at the basic education program for adults called EJA (“Educação de Jovens e Adultos”). After applying the exclusion criteria, 108 were recruited. Participants were divided into two groups: the control group (50 participants) attended the regular classes (literature, math, geography, history and sciences) and the intervention group (58 participants) attended part of the regular classes plus a specific training focused on learning how to read and write. Both groups attended their activities 4 days a week for 6 months. At the 6 month follow up visit, 77 participants successfully completed all required clinical assessments and interviews. Interviews were conducted to gather basic socio-demographic information, past and current medical history, use of tobacco, alcohol and illicit substances, physical activity levels and the presence of anxiety and depression. Participants also underwent a comprehensive cognitive assessment, which included executive functions assessment (digit span backwards, rapid number naming and phonemic verbal fluency), a functional brain MRI was performed to assess brain connectivity, especially the frontoparietal network, and a blood sample collection to measure plasma neurofilament levels. Results: We observed a significant increase in the episodic memory and executive functions in all participants, without a significant difference between the groups (control x intervention). When we adjusted the model for age, sex, reason for illiteracy and executive functions at baseline, we saw a significant improvement of executive functions in the intervention group. Factors that influenced in this result were attendance to classes combined with intensive literacy training, previous illiteracy related to rural areas residency, low executive performance at the baseline and lower levels of serum neurofilaments at baseline. In terms of brain connectivity, we saw that the intervention group had an increase in the frontal parietal and in the left hippocampal-temporal connectivity. Conclusion: Late life literacy training seems to improve executive functions, with and underlying rearrangement of the hippocampal and frontal connectivity.</jats:p>