Neurología

Longitudinal subcortical volume changes and their correlations with multiple PET and fluid biomarkers in dominantly inherited Alzheimer's disease

Wed, 01 Apr 2026 00:00:00 GMT

Longitudinal subcortical volume changes and their correlations with multiple PET and fluid biomarkers in dominantly inherited Alzheimer's disease Choo, Il Han; Park, Hoyoung; Gordon, Brian A.; Bateman, Randall J.; Dominantly Inherited Alzheimer Network; Daniels, Alisha; Courtney, Laura; Ziegemeier, Angela; Skrbec, Karina; Hellm, Cortaiga; Martin, Mariana; Ziegemeier, Ellen; Bartzel, Jamie; McDade, Eric; Libre-Guerra, Jorge J.; Supnet Bell, Charlene; Xiong, Chengie; Chrem Méndez, Patricio Alexis; Surace, Ezequiel Ignacio; Vázquez, Silvia; Allegri, Ricardo Francisco Background: Alzheimer's disease postmortem studies demonstrate that amyloid plaques and neurofibrillary tangles are present in subcortical regions. Objective: To investigate longitudinal subcortical structural changes in autosomal dominant Alzheimer's disease in relation to multiple PET and fluid biomarkers. Design: Dominantly Inherited Alzheimer's Network (DIAN) Observational study SETTING: Multicenter study PARTICIPANTS: Participants were identified as mutation-carriers of pathologic variants in presenilin-1, presenilin-2, or amyloid precursor protein and as non-carriers from the same families as the mutation-carriers. They underwent baseline and 2 and more times longitudinal follow-up assessments of multiple biomarkers MEASUREMENTS: Participants underwent structural MRI, ¹¹C-Pittsburgh Compound B PET, ¹⁸F-fluorodeoxyglucose PET, and CSF and plasma assessments. Rates of biomarker change as a function of estimated years to symptom onset were estimated using multivariate linear mixed-effects models, and longitudinal associations between subcortical atrophy and multiple biomarkers were evaluated. Results: A total of 601 participants completed one or more clinical evaluations, with up to eight annual visits. Mutation carriers showed significantly greater longitudinal atrophy in the left amygdala, bilateral thalamus, putamen, nucleus accumbens, and hippocampus compared with non-carriers (Bonferroni-corrected p < 0.05). The earliest divergence was observed 13.2 years before the expected symptom onset in the right nucleus accumbens, following amyloid-β (Aβ) accumulation in the right thalamus that began 23.8 years before onset. Among carriers, atrophy in the right thalamus, bilateral putamen, and bilateral nucleus accumbens was significantly associated with region-specific or cortical Aβ accumulation, as well as with CSF Aβ42, Aβ42/Aβ40 ratio, total tau, and phosphorylated tau (Bonferroni-corrected p < 0.05). Conclusions: The present findings may provide a unique and well-characterized model for investigating the temporal ordering of Alzheimer's disease biomarkers.

Levodopa-Induced dyskinesia in Latin America : Prevalence and associated clinical factors in the LARGE-PD cohort

Fri, 17 Apr 2026 00:00:00 GMT

Levodopa-Induced dyskinesia in Latin America : Prevalence and associated clinical factors in the LARGE-PD cohort Chaparro-Solano, Henry Mauricio; Teixeira-Dos-Santos, Daniel; Waldo, Emily; Leal, Thiago P.; Inca-Martinez, Miguel; Alcauter, Sarael; Medina-Rivera, Alejandra; Ruiz-Contreras, Alejandra E.; Cornejo Olivas, Mario; Mejia-Rojas, Koni; Armas, Cintia; Chaná Cuevas, Pedro; Rojas, Natalia; Orozco, Jorge L.; Muñoz Ospina, Beatriz; Aguillón, David; Buritica, Omar; Moreno Masmela, Sonia; Merello, Marcelo BackgroundAlthough levodopa is the gold standard treatment for Parkinson's disease (PD), its chronic use is associated with levodopa-induced dyskinesia (LID), a motor complication that impacts prognosis, quality of life, and treatment costs. Most known LID-associated factors have been identified in European-descendant populations.ObjectivesTo describe the epidemiology of LID in Latin American and Caribbean (LATAM) countries and assess the relevance of known and novel LID-associated factors in this population.MethodsWe conducted a cross-sectional study using data from the Latin American Research consortium on the Genetics of Parkinson's Disease (LARGE-PD). We included PD patients with information on LID status and levodopa use from eight LATAM countries. LID prevalence was calculated overall and by country. Countries were compared on demographic and clinical variables. Logistic regression was used to identify associations with LID.ResultsA total of 3695 PD patients (58.8% male) were included. Overall LID prevalence was 25.4% [95% CI: 24.06-26.87], ranging from 9.3% in Colombia to 45.1% in Puerto Rico. Prevalence increased progressively with longer disease duration. Country comparisons showed that not all known LID-associated factors explained prevalence differences. In logistic regression, fast disease progression was significantly associated with LID (OR: 1.55, 95%CI: 1.16-2.07), while sex was not (OR: 1.02, 95%CI: 0.87-1.18).ConclusionsThis is the largest study on LID epidemiology in LATAM. While some known risk factors remain relevant, others, like sex, do not, underscoring the need for population-specific studies. Future work should integrate environmental, clinical, and genetic data to better understand LID mechanisms.

Brief Cognitive Screening Tools for Dementia in Low-Educated Population from South America : A Systematic Review

Mon, 29 Sep 2025 00:00:00 GMT

Brief Cognitive Screening Tools for Dementia in Low-Educated Population from South America : A Systematic Review Chambergo Michilot, Diego; Custodio, Nilton; Montesinos, Rosa; Custodio, Belen; Cahuapaza Gutierrez, Nelson Luis; Caramelli, Paulo; Calandri, Ismael Luis; Dozzi Brucki, Sonia María; Suemoto, Claudia Kimie; Allegri, Ricardo Francisco; Slachevsky, Andrea; Parodi, Jose F. Introduction: Despite less education being common in Latin America, there is no systematic review on the use of brief cognitive screening (BCS) tools in illiterate and low-educated adults in the region. We systematically reviewed brief cognitive tests used to identify dementia in illiterate or low-educated adults from South America (SA). Methods: A systematic review was conducted according to the PRISMA and Cochrane guidelines. We searched four major databases: PubMed, Scopus, Web of Science, and Embase, for studies up to September 2023, and included observational studies that reported at least sensitivity, specificity, area under the receiver operating characteristic (ROC) curve, positive predictive value, or negative predictive value of dementia screening tools in illiterate or low-educated (less than 6 years of education) adults from SA. Results: Most studies in samples with illiteracy or low education across SA used BCS tools adapted to the local population's language. Seventeen tests were identified; among them, the Mini-Mental State Examination (MMSE) and Rowland Universal Dementia Assessment Scale (RUDAS) were the more common tools with good diagnostic accuracy in people with dementia. The sensitivity and specificity of reported BCS tools were at least 90%, and the area under the ROC curve was higher than 0.95. Conclusions: The cutoff points for detecting dementia in illiterates and the low-educated adult population of SA should be adjusted for most brief cognitive tests. Developing specific and sensitive cognitive batteries for our region for cognitive evaluation in low-educated/illiterate participants is mandatory, including specific functionality evaluation.

Collaborative Latin American Imaging Network In Neuroimmunology Research (BRAIMS) : Rationale, Structure, Challenges, and Future Directions

Mon, 01 Jun 2026 00:00:00 GMT

Collaborative Latin American Imaging Network In Neuroimmunology Research (BRAIMS) : Rationale, Structure, Challenges, and Future Directions Carnero Contentti, Edgar; Alonso, Ricardo; Boldrini, Vinícius; Cárcamo, Claudia A.; Casas, Magdalena; Ciampi, Ethel; Damasceno, Alfredo; dos Santos Silva, Jonadab; de Medeiros Rimkus, Carolina; Marrodán, Mariano; Navas, Carlos; Patrucco, Liliana; Pitombeira, Milena; Ramari, Cintia; Sato, Henry Koiti; Soler, Bernardita; Treviño Frenk, Irene; Wagner, Mario; Ontaneda, Daniel; Becker, Jefferson Magnetic resonance imaging (MRI) plays a central role in the diagnosis, differential diagnosis, and monitoring of neuroimmunological disorders, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). However, in Latin America (LATAM), variability in healthcare systems, imaging infrastructure, technical protocols, and subspecialized expertise limits the implementation of standardized MRI-based approaches and contributes to heterogeneity in diagnostic pathways and clinical decision-making. In this context, the Collaborative Latin American Imaging Network in Neuroimmunology Research (BRAIMS) was established as a regional initiative to strengthen MRI research and clinical practice in neuroimmunological diseases. BRAIMS emerged from a collaborative effort among neuroimmunologists, neuroradiologists, and researchers across multiple LATAM countries, with the aim of promoting methodological alignment, facilitating multicenter research, and generating region-specific real-world evidence. The network is structured to integrate core and collaborating centers under a coordinated governance model, enabling the development of shared research agendas and collaborative projects. Initial priorities include mapping MRI availability and practices across the region, standardizing acquisition protocols and reporting frameworks, identifying imaging-related sources of diagnostic variability, and developing consensus-based recommendations adapted to resource-variable settings. Despite sustained growth in neuroimmunology expertise in LATAM, important challenges persist, including unequal access to MRI technology, limited availability of advanced imaging techniques, variability in interpretation, and diagnostic complexity in populations with diverse clinical and epidemiological characteristics. By fostering regional collaboration and strengthening integration with international initiatives, BRAIMS aims to generate context-specific evidence, improve diagnostic accuracy, and enhance research capacity. This initiative represents a shift toward the production of regionally driven data, with the potential to contribute meaningfully to global neuroimmunology research and reduce disparities in access to high-quality neuroimaging.