Cognitive reserve in Down syndrome: a new opportunity to understand resilience in Alzheimer’s disease
Lídia Vaqué‐Alcázar, Maria Carmona‐Iragui, Laura Videla, Isabel Barroeta, Bessy Benejam, Íñigo Rodríguez‐Baz, Javier Arranz, Jordi Pegueroles, Alberto Lleó, Juan Fortea, David Bartrés‐Faz- Psychiatry and Mental health
- Cellular and Molecular Neuroscience
- Geriatrics and Gerontology
- Neurology (clinical)
- Developmental Neuroscience
- Health Policy
- Epidemiology
Abstract
Background
Traditionally, cognitive reserve (CR) and other related concepts underlying resilience, have been studied in the context of aging and Alzheimer’s disease (AD; Stern et al., 2020). Despite the increasing interest in elucidating how CR measures influence brain and cognitive development through a lifespan perspective (Kremen et al., 2019), its study in developmental diseases such as Down syndrome (DS) remains unexplored. Understanding the role of CR and its neurobiological mechanisms in DS is critical, since this population is genetically determined to develop AD (Fortea et al., 2021). During the last decades, people with DS have experienced an improvement in the number and quality of stimulating activities due to the higher inversions in disability services and community support resources. In this regard, our goal was to test whether this enriched environment would result in a generational effect showing a lower intellectual disability (ID) level and a higher intellectual profile as function of the birth year in DS.
Method
We selected a cross‐sectional subsample from the cohort study of adults with DS recruited at the Alzheimer‐Down Unit from the Catalan Down Syndrome Foundation and Hospital of Sant Pau. We included 528 participants with DS without clinical symptoms of AD born between 1955‐1995 (age: 39.25±9.27 years; 46.02% females). Participants with profound ID (as these individuals perform at floor scores) were excluded for Kaufman Brief Intelligence Test (K‐BIT) analyses (N = 379; age: 39.03±9.10 years; 48.02% females).
Result
Results evidenced a generational increase in the proportion of individuals with mild or moderate ID and a decrease in those with profound or severe ID level (Fig1). Similarly, a higher proportion of individuals acquired intellectual milestones (i.e., language, literacy, calculation; Fig2). Furthermore, our analyses revealed an increase in mean K‐BIT scores as function of the birth year (P<.001; Fig3).
Conclusion
There have been major changes in CR proxies in individuals with DS. Given the near full penetrance of AD in this population, characterizing the effect of these factors on AD presentation and pathophysiology could signify an important advance in the design of primary prevention plans in this particularly vulnerable population, which could probably be transferred to the general population.