Sergi Valero

Abstract Blood biomarkers have emerged as accurate tools for detecting Alzheimer’s disease (AD) pathology, offering a minimally invasive alternative to traditional diagnostic methods such as imaging and cerebrospinal fluid (CSF) analysis. Yet, the logistics surrounding venipuncture for blood collection, although considerably simpler than the acquisition of imaging and CSF, require precise processing and storage specific to AD biomarkers that are still guided by medical personnel. Consequently, limitations in their widescale use in research and broader clinical implementation exist. The DROP-AD project investigates the potential of dried plasma spot (DPS) and dried blood spot (DBS) analysis, derived from capillary blood, for detecting AD biomarkers, including phosphorylated tau at amino acid 217 (p-tau217), glial fibrillary acidic protein and neurofilament light. Here, 337 participants from 7 centers were included, with 304 participants providing paired capillary DPS or DBS and venous plasma samples. We observed strong correlations between DPS p-tau217 and venous plasma p-tau217 ( r S = 0.74, P < 0.001). DPS p-tau217 progressively increased with increasing disease severity, and showed good accuracy in predicting CSF biomarker positivity (area under the curve = 0.864). Similarly, we demonstrated the successful detection of glial fibrillary acidic protein and neurofilament light with strong correlations between DBS and DPS, respectively, using paired venous plasma samples. Notably, the method was also effective in individuals with Down syndrome, a population at high genetic risk for AD but in whom standard blood sampling by venipuncture may be more complicated, revealing elevated biomarkers in those with dementia compared with asymptomatic individuals. The study also explored unsupervised blood collection, finding high concordance between supervised and self-collected samples. These findings underscore the potential of dried blood collection and capillary blood as a minimally invasive, scalable approach for AD biomarker testing in research settings. Yet, further refinement of collection and analytical protocols is needed to fully translate this approach to be viable and useful as a clinical tool.

Introduction: Ageing is accompanied by gradual biological and cognitive changes that increase vulnerability to chronic diseases and neurodegenerative conditions. As populations age, dementia prevalence continues to rise, highlighting the need for earlier detection and personalised prevention strategies. Against this background, the COMFORTage project, funded by Horizon Europe, brings together a multidisciplinary consortium across 12 countries to advance innovative, scalable solutions for dementia care. By integrating digital platforms, biomarker research, and precision medicine, COMFORTage seeks to develop artificial intelligence (AI)-driven tools that support more precise and adaptive interventions. Central to this effort are the Virtualized AI-Based Healthcare Platform and Patient Digital Twins, which enable personalised monitoring and decision support. Within this framework, Pilot 3 at Ace Alzheimer Center Barcelona focuses on individuals with mild cognitive impairment and mild Alzheimer's disease dementia, evaluating the effects of cognitive and functional stimulation and contributing multimodal data to optimise the AI platform. Methods: Pilot 3 is a randomised, open-label study involving retrospective and prospective datasets. Participants undergo clinical, genetic, neuropsychological, cerebrospinal fluid (CSF) and plasma biomarker assessments, magnetic resonance imaging (MRI), and spontaneous speech analysis. The primary outcomes assess cognitive decline using composite scores from the Neuropsychological Battery used in Ace (NBACE), targeting attention, memory, visuospatial/perceptual functions, executive functions, and language, over a two-year follow-up. Three digital platforms provided by the consortium will be used as cognitive and functional stimulation tools for participants. The intervention's effects on cognitive decline will be evaluated through changes in NBACE composite scores. Secondary objectives include assessing impacts on physical, psychological, social, and functional well-being; examining associations between biological variables and cognitive changes; and analyzing spontaneous speech as a remote, scalable proxy for cognitive status. Discussion: Findings from Pilot 3 will contribute to COMFORTage's broader mission, offering critical insights into the scalability and real-world implementation of AI-powered dementia care solutions. This integrated approach highlights the potential of precision medicine and advanced digital tools to elevate global standards in dementia management. Clinical Trial Registration: identifier NCT07031167.

Isolated word meanings are inherently uncertain. This uncertainty reduces when they are combined and anchored in context. We propose that grammar compresses meaning uncertainty cross-linguistically, which is reflected in brain and selectively disrupted in disorders. Compression was operationalized as the relative difference between non-contextual surprisal estimated from lexical frequency, and contextual surprisal from grammar-sensitive models. In narratives from 20 languages, contextual surprisal reduced frequency-based surprisal. This reduction closely tracked the surprisal cost of reversing word order, and scaled with richer, non-redundant lexis as organized by more complex but optimal dependency structure. During fMRI, surprisal and its reduction explained BOLD activity for comprehension and production in overlapping but distinct regions. Uncertainty reduction was significantly attenuated in aphasia, dementia, and schizophrenia, but remained intact where primary deficit is not language. These findings position uncertainty reduction via grammar as a foundational concept that illuminates principles, brain basis, and disruptions of language.

Abstract Background Recent studies suggest that copy number variants (CNVs) may contribute to the missing heritability of complex diseases such as Alzheimer’s disease (AD) and related dementias (ADRD). Methods We performed a CNV analysis using genotyping data (Axiom 815K Spanish biobank array) from the GR@ACE/DEGESCO dementia dataset (n=20,067) of the Spanish population. Applying PennCNV and extensive quality control, 8,275 controls and 7,818 dementia cases were selected for gene-level case/control associations. Results We identified 43,833 CNVs with deletions (47%) and duplications (53%). No genome-wide significant associations were found, but nominal associations were observed in PKP3 - SIGIRR and FBRSL1 loci. CNVs in 2,970 genes were exclusive to dementia cases, enriched in vascular-related pathways. Notable findings included 14q11.2 duplication and VPS13B deletions in ADRD cases, the latter confirmed by optical genome mapping. Conclusion Our findings suggest potential novel genes associated with ADRD in the Spanish population. However, the limited resolution of array-based technologies in detecting CNVs warrants further investigation.

BACKGROUND: The apolipoprotein E (APOE) ε4 allele remains the strongest genetic risk factor for late-onset Alzheimer's disease (AD), yet the marked variability in its pathogenicity suggests underlying genetic complexity. Historically, efforts to resolve the intragenic architecture of APOE have been hampered by the limitations of conventional genotyping and short-read sequencing, as well as the presence of homoplasy in common intragenic markers-misleading similarities arising from convergent variants. OBJECTIVE: We leveraged Oxford Nanopore Technology (ONT) to phase intragenic APOE variants, resolve homoplasy, and examine the impact of phased haplotypes on cerebrospinal fluid (CSF) APOE protein levels and AD progression. METHODS: Using long-read sequencing in a Spanish memory clinic cohort (n = 1,267), we reconstructed full-length 4 kb APOE haplotypes, identifying 59 unique configurations grouped into five major haplogroups. Common intragenic variants defined ancestral ε4 (4A, 4B) and ε3 (3A, 3B) haplogroups. These were analyzed for associations with CSF APOE levels (Olink platform) and progression from mild cognitive impairment (MCI) to dementia using adjusted Cox regression models. RESULTS: ONT sequencing successfully resolved homoplasy between the APOE promoter region-particularly at rs405509-and the canonical protein isoforms, uncovering common but functionally distinct ε3A/B and ε4A/B intragenic sub-haplotypes with independent biological effects. Carriers of the ε4A haplotype exhibited significantly lower CSF APOE protein levels (p = 0.004), whereas the ε3B haplotype was associated with elevated CSF APOE protein levels (p = 0.025). Notably, both haplotypes were linked to a slower progression from MCI to AD, independent of APOE genotype, age, sex and core CSF biomarkers. CONCLUSION: This study redefines the human APOE ε3 and ε4 alleles as genetically heterogeneous entities. Using ONT long-read sequencing, we achieved high-resolution mapping of intragenic haplotypic structure and regulatory variation previously obscured by conventional approaches. This enabled the identification of ancestral haplotypes with distinct functional profiles and potential relevance to Alzheimer's disease pathogenesis. These findings highlight the importance of incorporating haplotype-level resolution into Alzheimer's risk assessment, therapeutic targeting, and precision medicine strategies.