Neurología Cognitiva

Characterizing circadian rest-activity rhythm patterns across Alzheimer's disease continuum in Down syndrome

Fri, 01 May 2026 00:00:00 GMT

Characterizing circadian rest-activity rhythm patterns across Alzheimer's disease continuum in Down syndrome Giménez, Sandra; Vaqué-Alcázar, Lídia; Clos, Susana; Benejam, Bessy; Carmona-Iragui, María; Maure Blesa, Lucia; Videla, Laura; Zhu, Nuole; Altuna, Miren; Arranz, Javier; Barroeta, Isabel; Rodríguez-Baz, Íñigo; Bejanin, Alexandre; Bueno, Ana; Fernández, Susana; Del Hoyo Soriano, Laura; Pertierra, Lucía; Alcolea, Daniel; Miller, Bruce; Grinberg, Lea T. Introduction: Sleep and circadian rest-activity rhythm (RAR) disruption may bidirectionally relate to Alzheimer's disease (AD). Down syndrome (DS), the most common genetic cause of AD, presents sleep disorders, yet RAR patterns across the DS-associated AD continuum remain uncharacterized. Methods: We analyzed 7-day wrist actigraphy in 140 adults with DS (108 asymptomatic; 32 AD dementia) and 41 unimpaired controls. General linear models, adjusted for age, sex, sleep efficiency, and obstructive sleep apnea (OSA) severity, tested group differences, with interaction terms included to evaluate group-specific associations. Results: DS showed lower relative amplitude and higher nocturnal activity, already in asymptomatic individuals. Rhythm strength declined further with AD progression, while regularity and phase timing remained preserved until dementia. Findings were independent of sleep duration and OSA. Discussion: Adults with DS showed early RAR disturbance that progressed across the AD continuum, paralleling sporadic AD. Circadian RAR features may be scalable biomarkers of AD progression.

Regression-based normative data for neuropsychological assessment in Buenos Aires, Argentina: RAVLT, trail making test, digit span, and verbal fluency

Mon, 11 May 2026 00:00:00 GMT

Regression-based normative data for neuropsychological assessment in Buenos Aires, Argentina: RAVLT, trail making test, digit span, and verbal fluency Corvalán, Nicolás; Morello García, Florentina; Leiva, Samanta; Allegri, Ricardo Francisco; Crivelli, Lucía Objective: To develop regression-based normative data for a set of widely used neuropsychological tests and to provide a freely accessible normative data calculator for use in Buenos Aires, Argentina. Methods: Participants were drawn from a large clinical dataset and selected to reflect preserved global cognition, intact memory performance, and functional independence. Regression-based norms were developed for the Rey Auditory Verbal Learning Test, Verbal Fluency, Trail Making Test, and Digit Span tasks. For each model, predictors included age, sex, and years of education, as well as polynomial terms and interaction effects; final models were obtained via stepwise backward elimination procedures. Model assumptions were evaluated, and predictive performance was estimated using 10-fold cross-validation. Results: 393 participants met inclusion criteria. Age was negatively associated with verbal memory, fluency, and executive function, whereas higher educational attainment was associated with better performance. Women outperformed men in verbal memory and phonological fluency. Demographic variables explained between 2% and 23% of variance across tests. An open-access calculator was developed to facilitate individualized normative estimation in clinical settings. Conclusions: This study provides locally developed, regression-based norms for neuropsychological assessment in Buenos Aires – Argentina, addressing the lack of culturally relevant norms and limitations of traditional methods.

Beyond Genetics: The Influence of Socioeconomic Status on Dominantly Inherited Alzheimer’s Disease Progression

Tue, 23 Dec 2025 00:00:00 GMT

Beyond Genetics: The Influence of Socioeconomic Status on Dominantly Inherited Alzheimer’s Disease Progression Clarens, María Florencia; Fernández, Rodrigo Sebastián; Karch, Celeste M.; McDade, Eric; Llibre Guerra, Jorge J.; Allegri, Ricardo Francisco; Chrem Méndez, Patricio Alexis; Dominantly Inherited Alzheimer Network (DIAN) Background: Social inequalities are key health determinants shaping Alzheimer’s disease (AD) progression. In dominantly inherited Alzheimer’s disease (DIAD), where genetic causes are established, the influence of socioeconomic status (SES) on cognitive and functional outcomes remains underexplored. This study examines how SES impacts DIAD progression, offering insights into the role of social risk factors in a genetically defined AD model. Method: Data from 421 participants in the Dominantly Inherited Alzheimer Network (DIAN) across 10 countries was analyzed, including 158 non‐mutation carriers (nMC), 170 asymptomatic mutation carriers (aMC), and 93 symptomatic mutation carriers (sMC). Using hierarchical linear mixed models, we evaluated the longitudinal effects of SES, measured by the Hollingshead Social Class Index (SC), on cognition (DIAN Cognitive Composite) and function (Clinical Dementia Rating Scale Sum of Boxes, CDR‐SB). We identified an optimal change point (CP) near estimated years from onset (EYO) to detect when mutation carriers diverged from non‐carriers. Interactions among SC, mutation status, time, and proximity to symptomatic onset were modeled. Result: Cognitive trajectories revealed a significant four‐way interaction (Mutation × Time × Baseline EYO × SC, p < 0.020), indicating SES moderates the combined effects of mutation status, time, and proximity to onset. Another interaction (Mutation × Time × CP_EYO_final × SC; p < 0.017) confirmed SES’s role in influencing cognitive decline. Lower SES was consistently associated with greater cognitive decline among mutation carriers, as verified through simple slopes analyses and Johnson‐Neyman intervals (p < 0.05, Figure 1). Analyses of CDR‐SB revealed consistent patterns, indicating that SES similarly affects functional outcomes (Figure 2). Conclusion: SES significantly affects cognitive and functional trajectories in DIAD, highlighting the role of social determinants in disease variability. These findings suggest social inequalities exacerbate DIAD progression, finding that could be extrapolated to sporadic AD. Addressing social determinants of health is critical in genetically defined populations to improve outcomes and mitigate disparities.

Integrating city design into lifestyle trials: urban greenness shapes physical activity levels across 12 cities in the LatAm FINGERS trial.

Tue, 23 Dec 2025 00:00:00 GMT

Integrating city design into lifestyle trials: urban greenness shapes physical activity levels across 12 cities in the LatAm FINGERS trial. Spiousas, Ignacio; Coldeira, María Florencia; Suemoto, Claudia Kimie; Baena, Ana Y.; Salinas Contreras, Rosa María; Caramelli, Paulo; Brucki, Sonia; Nitrini, Ricardo; Sosa, Ana Luisa; Crivelli, Lucía; Sevlever, Gustavo Emilio; Custodio, Nilton; Acosta, Daisy; Charamelo, Ana; Delgado, Carolina; Cusicanqui, María Isabel; Jiménez Velázquez, Ivonne; Duque Peñailillo, Lissette; Calandri, Ismael Luis; LatAm-FINGERS Consortium Background: LatAm FINGERS is a feasibility trial aimed at preventing cognitive decline in individuals at risk through lifestyle changes in Latin America, with its objectives aligned with the RE‐AIM (Reach, Effectiveness, Adoption and Implementation) framework. An essential component of this framework is adoption, which emerges from the interaction between participants, the trial procedures, and their environment. Given that the intervention focuses on lifestyle modifications, it is crucial to consider an often‐overlooked factor: the city where participants live and its influence on behavior. A clear example is the relationship between physical activity and the availability of spaces that support it. Urban greenness refers to the collection of green spaces within a city. We aimed to examine how accessibility to green spaces influences the amount of physical activity performed by participants before starting the LatAm‐FINGERS trial. Method: We geolocated the residences of 1,800 screened individuals from 12 Latin American cities. Using publicly available data, we estimated isochrones, or areas reachable within a 15‐minute walk (3.4 km/h), along city pathways. As a measure of greenness, we calculated the surface area of public green spaces within each isochrone and the distance to the nearest green space. Physical activity was assessed using the International Physical Activity Questionnaire (IPAQ) and converted into metabolic equivalent of task (MET) units. A generalized linear mixed‐effects model assessed whether weekly physical activity levels (in METs/week) were associated with walkable green space availability. The model was adjusted for socioeconomic status, education, sex, mobility assistance needs, depression, smoking, and co‐morbid conditions. Result: Walking was the most common physical activity, with weekly METs averaging 126.5 (SD=108.4), representing 70.2% (SD=10.8%) of total physical activity. While the total green space area had a minimal effect on walking (β=−0.0004, 95%CI=‐0.0017, 0.0001), distance to the nearest green space influenced walking levels (β=‐0.0440, 95%CI=‐0.1874, 0.0982). For each block farther a participant's home was from a green space, weekly walking METs decreased by 3%. Conclusion: These results highlight the importance of green spaces in promoting physical activity. Future steps will explore whether urban greenness also influences intervention adherence to the physical activity program and other measures of wellbeing.