Search Results (11,039)

Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique that utilizes magnetic fields to induce cortical electric currents, enabling both the measurement and modulation of neuronal activity. Initially developed as a diagnostic tool, TMS now serves dual roles in clinical neurology, offering insight into neurophysiological dysfunctions and the therapeutic modulation of abnormal cortical excitability. This review examines key TMS outcome measures, including motor thresholds (MT), input–output (I/O) curves, cortical silent periods (CSP), and paired-pulse paradigms such as short-interval intracortical inhibition (SICI), short-interval intracortical facilitation (SICF), intracortical facilitation (ICF), long interval cortical inhibition (LICI), interhemispheric inhibition (IHI), and short-latency afferent inhibition (SAI). These biomarkers reflect underlying neurotransmitter systems and can aid in differentiating neurological conditions. Diagnostic applications of TMS are explored in Parkinson’s disease (PD), dystonia, essential tremor (ET), Alzheimer’s disease (AD), and mild cognitive impairment (MCI). Each condition displays characteristic neurophysiological profiles, highlighting the potential for TMS-derived biomarkers in early or differential diagnosis. Therapeutically, repetitive TMS (rTMS) has shown promise in modulating cortical circuits and improving motor and cognitive symptoms. High- and low-frequency stimulation protocols have demonstrated efficacy in PD, dystonia, ET, AD, and MCI, targeting the specific cortical regions implicated in each disorder. Moreover, the successful application of TMS in differentiating and treating AD and MCI underscores its clinical utility and translational potential across all neurodegenerative conditions. As research advances, increased attention and investment in TMS could facilitate similar diagnostic and therapeutic breakthroughs for other neurological disorders that currently lack robust tools for early detection and effective intervention. Moreover, this review also aims to underscore the importance of maintaining standardized TMS protocols. By highlighting inconsistencies and variability in outcomes across studies, we emphasize that careful methodological design is critical for ensuring the reproducibility, comparability, and reliable interpretation of TMS findings. In summary, this review emphasizes the value of TMS as a distinctive, non-invasive approach to probing brain function and highlights its considerable promise as both a diagnostic and therapeutic modality in neurology—roles that are often considered separately. Full article

Background: Cholinesterase inhibitors (ChEIs) are commonly prescribed for the treatment of Alzheimer’s disease (AD) and achieve long-term benefits for cognition and survival in real-world settings. However, the discontinuation rate is high due to their side effects, with gastrointestinal (GI) symptoms hampering long-term prescriptions. The risk of side effects associated with rivastigmine was previously shown to be lower with transdermal delivery than with oral capsules; however, this has yet to be examined in detail for donepezil, the most widely used ChEI. The daily application of a donepezil transdermal patch was officially approved in Japan in 2023. The incidence of side effects was lower with the donepezil transdermal patch than with oral donepezil in healthy volunteers, but has not yet been assessed in clinical settings. Results: We herein report three AD patients in two different memory clinics who developed GI symptoms with oral ChEIs that were attenuated by switching to the donepezil transdermal patch. Conclusions: The donepezil transdermal patch may improve tolerability and adherence in patients who develop gastrointestinal adverse effects with oral donepezil. Full article

Alzheimer’s disease (AD) is a prevalent neurodegenerative condition that progressively impairs cognitive processes, particularly learning and memory. A key pathological feature of AD involves senile plaques mainly composed of β-amyloid (Aβ) peptides, generated via the amyloidogenic pathway from amyloid precursor protein (APP) through sequential β-secretase (BACE1) and γ-secretase cleavage, positioning BACE1 inhibition as a prime therapeutic target. In this study, we applied bioassay-guided fractionation of the butanol-soluble fraction from Dryopteris crassirhizoma rhizomes, previously reported to inhibit Aβ production, to isolate and characterize Aβ-lowering constituents. Through successive chromatographic steps, nine compounds were isolated and structurally classified into flavonoids, chromones, and phloroglucinols, including epicatechin (1), β-carboxymethyl-(-)-epicatechin (2), 7-methoxy-isobiflorin (3), biflorin (4), eriodictyol (5), noreugenin (6), phloroglucinols (butyrylphloroglucinol (7), 2-propionyl-4-methylphloroglucinol (8), and 2-butyryl-4-methylphloroglucinol (9) by comprehensive spectroscopic analysis (NMR, MS, UV, IR). These compounds were assessed for effects on sAPPβ and BACE1 (β-secretase) levels by Western blot, with Aβ production quantified via ELISA in a cellular AD model (APP-CHO cells). Compounds 5–9 significantly reduced sAPPβ and BACE1 expression while potently suppressing Aβ generation. These results demonstrate that diverse constituents from D. crassirhizoma rhizomes inhibited Aβ production through BACE1 suppression, highlighting their potential as natural lead compounds for AD prevention or therapy. Full article

Neurodegenerative diseases (NDDs), including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), are becoming more prevalent and still lack effective disease-modifying therapies (DMTs). However, translational efficiency remains critically low. For example, a ClinicalTrials.gov analysis of AD programs (2002–2012) estimated ~99.6% attrition, while PD programs (1999–2019) achieved an overall success rate of ~14.9%. In vitro platforms are assessed, ranging from immortalized neuronal lines and primary cultures to human-induced pluripotent stem cell (iPSC)-derived neurons/glia, neuron–glia co-cultures (including neuroinflammation paradigms), 3D spheroids, organoids, and blood–brain barrier (BBB)-on-chip systems. Complementary in vivo toxin, pharmacological, and genetic models are discussed for systems-level validation and central nervous system (CNS) exposure realism. The therapeutic synthesis focuses on AD, covering symptomatic drugs, anti-amyloid immunotherapies, tau-directed approaches, and repurposed drug classes that target metabolism, neuroinflammation, and network dysfunction. This review links experimental models to translational decision-making, focusing primarily on AD and providing a brief comparative context from other NDDs. It also covers emerging targeted protein degradation (PROTACs). Key priorities include neuroimmune/neurovascular human models, biomarker-anchored adaptive trials, mechanism-guided combination DMTs, and CNS PK/PD-driven development for brain-directed degraders. Full article

Type 2 Diabetes Mellitus (T2DM) is a recognized risk factor for Alzheimer’s Disease (AD), as epidemiological research indicates that those with T2DM have a markedly increased risk of experiencing cognitive decline and dementia. Chronic hyperglycemia and insulin resistance in T2DM hinder cerebral glucose metabolism, reducing the primary energy source for neurons and compromising synaptic function. Insulin resistance impairs signaling pathways crucial for neuronal survival and plasticity, while high insulin levels compete with amyloid-β (Aβ) for breakdown by insulin-degrading enzyme, promoting Aβ buildup. Additionally, vascular issues linked to T2DM impair blood–brain barrier functionality, decrease cerebral blood flow, and worsen neuroinflammation. Elevated oxidative stress and advanced glycation end-products (AGEs) in diabetes exacerbate tau hyperphosphorylation and mitochondrial dysfunction, worsening neurodegeneration. Collectively, these processes create a robust biological connection between T2DM and AD, emphasizing the significance of metabolic regulation as a possible treatment approach for preventing or reducing cognitive decline. Here, we review the relationship between T2DM and AD and discuss the roles insulin, hyperglycemia, and inflammation therapeutic strategies have in successful development of AD therapies. Additionally evaluated are recent therapeutic advances, especially involving the polyflavonoid anthocyanin, against T2DM-mediated AD pathology. Full article

Background: Alzheimer’s disease (AD) features progressive cognitive decline and amyloid-beta (Aβ) accumulation. Insulin resistance in type 2 diabetes mellitus (T2DM) is increasingly recognised as a mechanistic link between metabolic dysfunction and neurodegeneration. Although sodium–glucose cotransporter-2 inhibitors (SGLT2is) have established glycaemic and cardioprotective benefits, their neuroprotective role remains less well defined. Objectives: This systematic review examines animal studies on the neuroprotective effects of SGLT2i in T2DM and AD models. Methods: A literature search was conducted across the Web of Science, Scopus, and PubMed databases, covering January 2014 to November 2024. Heterogeneity was assessed with I², and data were pooled using fixed-effects models, reported as standardised mean differences with 95% confidence intervals. We focus on spatial memory performance as measured by the Morris Water Maze (MWM) test, including escape latency and time spent in the target quadrant, as the primary endpoints. The secondary endpoints of Aβ accumulation, oxidative stress, and inflammatory markers were also analysed and summarised. Results: Twelve studies met the inclusion criteria for this review. A meta-analysis showed that SGLT2i treatment significantly improved spatial memory by reducing the escape latency in both T2DM and AD models. In addition, SGLT2i yielded a significant improvement in spatial memory, as indicated by an increased target quadrant time for both T2DM and AD. Furthermore, SGLT2i reduced Aβ accumulation in the hippocampus and cortex, which met the secondary endpoint; the treatment also lessened oxidative stress and inflammatory markers in animal brains. Conclusions: Our findings indicate that SGLT2is confer consistent neuroprotective benefits in experimental T2DM and AD models. Full article

This review summarizes the role of nuclear factor erythroid 2–related factor 2 (Nrf2) as a common link between aging, neurodegeneration, and neuropathic pain. Aging is characterized by oxidative stress and constant inflammation, which coincides with reduced Nrf2 activity and weaker antioxidant responses, increasing vulnerability to diseases. In neurodegenerative disorders—including Alzheimer’s, Parkinson’s, Huntington’s disease, and amyotrophic lateral sclerosis—evidence indicates that impaired Nrf2 signaling contributes to oxidative damage, neuroinflammation, and mitochondrial dysfunction. Furthermore, in neuropathic pain, similar mechanisms are involved, and Nrf2 could play a role as a potential analgesic target because of its role in regulating cellular defense pathways. We also review natural Nrf2 modulators (e.g., flavonoids, other polyphenols, terpenoids, alkaloids), discussing their benefits alongside common translational limitations such as poor solubility, low oral bioavailability, rapid metabolism, and potential safety issues, including possible pro-oxidant effects and chemoresistance. We also outline future directions that should prioritize improving delivery systems, addressing NRF2/KEAP1 gene variations, evaluating combinations with standard therapies, exploring preventive applications, and defining dosing, treatment duration, and long-term safety. Overall, current evidence indicates that Nrf2 modulation is a practical, cross-cutting approach relevant to healthy aging and disease management. Full article

Objective: Alzheimer’s disease (AD) and other forms of dementia are a heterogeneous group of neurodegenerative diseases characterized by progressive cognitive decline. Differential diagnosis between AD and other dementias is crucial for choosing the optimal treatment strategy. Currently, cerebrospinal fluid (CSF) analysis remains the most accurate diagnostic method, but its invasiveness limits its use. In this regard, the search for reliable biomarkers in the blood is an urgent task. Methods: The study included 31 dementia patients (23 women and 8 men) diagnosed via interdisciplinary consultations and neuropsychological testing (MMSE ≤ 24). CSF and blood plasma samples were collected and analyzed using Luminex technology. Biomarker concentrations were measured, and statistical analyses (ANOVA, Kruskal–Wallis, and Pearson correlation) were performed to compare groups and assess correlations. Results: Levels of Aβ40 and Aβ42 in CSF were significantly lower in patients with AD compared with non-AD dementia (p = 0.02 and p < 0.001, respectively). The Aβ42/40 ratio in CSF was higher in patients with non-AD dementia (p = 0.048). The concentration of Aβ42 in blood plasma was increased in patients with AD (p = 0.001). Positive correlations were found between Aβ42 in CSF and TDP-43 in plasma in non-AD dementia (r = 0.97, p < 0.001), as well as between neurogranin and TDP-43 in plasma in AD (r = 0.845, p < 0.001). Conclusions: The study demonstrates the potential of blood biomarkers, in particular Aβ42, for the differential diagnosis of AD and other forms of dementia. The discovered correlations between CSF and plasma biomarkers deepen the understanding of neurodegenerative processes and contribute to the development of noninvasive diagnostic methods. Full article

The blood–brain barrier (BBB) restricts therapeutic delivery to the central nervous system (CNS), hindering the treatment of neurological disorders, such as Alzheimer’s disease, Parkinson’s disease, brain cancers, and stroke. Aptamers, short single-stranded DNA or RNA oligonucleotides that can fold into unique 3D shapes and bind to specific target molecules, offer high affinity and specificity, low immunogenicity, and promising BBB penetration via receptor-mediated transcytosis targeting receptors such as the transferrin receptor (TfR) and low-density lipoprotein receptor-related protein 1 (LRP1). This review examines aptamer design through the Systematic Evolution of Ligands by Exponential Enrichment (SELEX) and its variants, mechanisms of BBB crossing, and applications in CNS disorders. Recent advances, including in silico optimization, in vivo SELEX, BBB chip-based MPS-SELEX, and nanoparticle–aptamer hybrids, have identified brain-penetrating aptamers and enhanced the brain delivery efficiency. This review highlights the potential of aptamers to transform CNS-targeted therapies. Full article

This work was inspired by quercetin, a natural bioflavonoid with well-known neuroprotective properties. We synthesized a new functional monomer, 3-acryloxy-3′,4′,5,7-tetramethylquercetin 1, and used it to prepare, for the first time, a molecularly imprinted polymer (MIP) selective for donepezil, the main drug used in Alzheimer’s disease therapy. The polymer was designed to be fluorescent and responsive to pH changes, aiming for controlled drug release. The optimized MIP-4, produced from a 1:1 mixture of the monomer 1 and acrylic acid, was characterized by FTIR-ATR, fluorescence spectroscopy, SEM, and DLS, confirming its chemical composition, morphology, particle size distribution and zeta potential. Adsorption studies showed higher donepezil binding capacity for MIP than for NIP, highlighting the polymer’s selective recognition. In vitro release experiments at pH 3, 5.5, and 7 revealed a pH-dependent behaviour, with nearly 98% cumulative donepezil release at pH 7. The polymer was non-cytotoxic and successfully released donepezil in in vitro assays, enabling effective inhibition of eeAChE. These results provide a proof of concept supporting the potential of quercetin-derived fluorescent molecularly imprinted polymers as selective and stimuli-responsive platforms for donepezil delivery. Full article

Background/Objectives: Dementia represents a growing public health challenge. The WHO Global Action Plan on the Public Health Response to Dementia emphasizes early detection, risk reduction, and innovation as key priorities. Mild Behavioral Impairment (MBI), defined as the emergence of persistent neuropsychiatric symptoms in older individuals, represents a potential marker of early neurodegeneration and possible window for early intervention. This review explores the role of MBI in dementia prevention, mapping current evidence within the WHO Global Action Plan framework. Methods: A comprehensive search was performed in PubMed, Scopus, and the official WHO website, during 1 September 2025–10 November 2025, without time restrictions. Eligible sources included original clinical studies, reviews, and policy documents addressing MBI, dementia prevention, and public health. Data were thematically synthesized according to the seven objectives of WHO: (1) dementia as a public health priority, (2) dementia awareness and friendliness, (3) dementia risk reduction, (4) dementia diagnosis, treatment, care and support, (5) support for dementia carers, (6) information systems for dementia, and (7) dementia research and innovation. Results: Accumulating evidence indicates that MBI assessment can capture early behavioral manifestations of neurodegenerative and other forms of dementia, correlating with fluid, neuroimaging and genetic biomarkers. Integrating MBI screening through the easy-to-administer MBI Checklist (MBI-C) into clinical and community-based care, including telemedicine pathways and research, may enhance early identification and personalized interventions, enrich the pool for clinical trials, and facilitate research in biomarker and therapy. MBI-related research further supports its integration in remote digital monitoring and population-based prevention. Conclusions: Embedding MBI-informed screening and interventions into national dementia strategies aligns with WHO objectives for early, equitable and scalable prevention and brain health. Full article

Background/Objectives: Dementia, characterised by cognitive decline, significantly impacts language abilities. While the risk of dementia increases with age, it often manifests years before clinical diagnosis. Identifying early warning signs is crucial for timely intervention. Previous research has demonstrated that changes in language, such as reduced vocabulary diversity and simpler sentence structures, may be observed in individuals with dementia. This study investigates the potential of linguistic analysis to detect early signs of cognitive decline by examining the writing of Sir Terry Pratchett, a renowned author diagnosed with Posterior Cortical Atrophy (PCA), typically a form of dementia caused by Alzheimer’s disease. Methods: This study analysed 33 Discworld novels by Terry Pratchett, comparing linguistic features before and after a potential turning point identified through analysis of adjective type-token ratios (TTR). Results: A significant decrease in lexical diversity (TTR) was observed for nouns and adjectives in later works. Total wordcount increased, while lexical diversity decreased, suggesting a shift towards simpler language. This shift coincided with a decrease in adjective TTR below a defined threshold, occurring approximately ten years before Pratchett’s formal diagnosis. Conclusions: These findings suggest that subtle changes in linguistic patterns, such as decreased lexical diversity, may precede clinical diagnosis of dementia by a considerable margin. This research highlights the potential of linguistic analysis as a valuable tool for early detection of cognitive decline. Further research is needed to validate these findings in larger cohorts and explore the specific linguistic markers associated with different types of dementia. Full article

Neurodegenerative disorders are characterized by progressive neuronal loss and dysfunction, yet increasing evidence indicates that glial cells are central mediators of both disease initiation and progression. Astrocytes, microglia, and oligodendrocyte lineage cells modulate neuronal survival by regulating neuroinflammation, metabolic support, synaptic maintenance, and proteostasis. However, dysregulated glial responses, including chronic microglial activation, impaired phagocytosis, altered cytokine production, and mitochondrial dysfunction, contribute to persistent inflammation and structural degeneration observed across Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, Huntington’s disease and multiple sclerosis. Recent advances in single-cell and spatial omics have revealed extensive glial heterogeneity and dynamic shifts between neuroprotective and neurotoxic phenotypes, emphasizing the context-dependent nature of glial activity. This review summarizes current knowledge regarding the multifaceted involvement of glial cells in neurodegenerative disorders. Full article

Alzheimer’s Disease (AD) is an advanced brain illness that affects millions of individuals across the world. It causes gradual damage to the brain cells, leading to memory loss and cognitive dysfunction. Although Magnetic Resonance Imaging (MRI) is widely used in AD diagnosis, the existing studies rely solely on the visual representations, leaving alternative features unexplored. The objective of this study is to explore whether MRI sonification can provide complementary diagnostic information when combined with conventional image-based methods. In this study, we propose a novel dual-stream multimodal framework that integrates 2D MRI slices with their corresponding audio representations. MRI images are transformed into audio signals using a multi-scale, multi-orientation Gabor filtering, followed by a Hilbert space-filling curve to preserve spatial locality. The image and sound modalities are processed using a lightweight CNN and YAMNet, respectively, then fused via logistic regression. The experimental results of the multimodal achieved the highest accuracy in distinguishing AD from Cognitively Normal (CN) subjects at 98.2%, 94% for AD vs. Mild Cognitive Impairment (MCI), and 93.2% for MCI vs. CN. This work provides a new perspective and highlights the potential of audio transformation of imaging data for feature extraction and classification. Full article

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder marked by decreased amyloid-beta (Aβ) clearance, enhanced Aβ aggregation, an increased risk of amyloid-related imaging abnormalities (ARIA), and blood–brain barrier (BBB) dysfunction. The APOE4 allele, being the leading genetic risk factor for AD, contributes strongly to these symptoms. This review covers the relationship between APOE4 status and the efficacy of FDA-approved monoclonal antibody (mAb) therapies, namely aducanumab, lecanemab, and donanemab. Across several clinical trials, APOE4 carriers exhibited higher rates of ARIA-E and ARIA-H compared to non-carriers. While the therapies did often meet biomarker endpoints (i.e., reduced amyloid), benefits were only observed in early and mild AD, and cognitive benefits were often marginal. Going forward, experimental apoE4-targeted immunotherapies may ease the burden of APOE4-related pathology. The field is shifting towards a more integrated approach, focusing on earlier interventions, biomarker-driven precision treatment, and improved drug delivery systems, such as subcutaneous injections, receptor-mediated transport, and antibodies with enhanced BBB penetration. As it stands, high treatment costs, limited accessibility, and strict eligibility criteria all stand as barriers to treatment. By integrating the APOE4 genotype into treatment planning and focusing on disease-stage-specific approaches, a safer and more effective means of treating AD could be achieved. Full article