Alzheimer\'s disease (AD) presents a significant challenge to global health. It is characterized by progressive cognitive deterioration and increased rates of morbidity and mortality among older adults. Among the various pathophysiologies of AD, mitochondrial dysfunction, encompassing conditions such as increased reactive oxygen production, dysregulated calcium homeostasis, and impaired mitochondrial dynamics, plays a pivotal role. This review comprehensively investigates the mechanisms of mitochondrial dysfunction in AD, focusing on aspects such as glucose metabolism impairment, mitochondrial bioenergetics, calcium signaling, protein tau and amyloid-beta-associated synapse dysfunction, mitophagy, aging, inflammation, mitochondrial DNA, mitochondria-localized microRNAs, genetics, hormones, and the electron transport chain and Krebs cycle. While lecanemab is the only FDA-approved medication to treat AD, we explore various therapeutic modalities for mitigating mitochondrial dysfunction in AD, including antioxidant drugs, antidiabetic agents, acetylcholinesterase inhibitors (FDA-approved to manage symptoms), nutritional supplements, natural products, phenylpropanoids, vaccines, exercise, and other potential treatments.

UNASSIGNED: As the prevalence of Alzheimer\'s disease (AD) grows with an aging population, the need for early diagnosis has led to increased focus on electroencephalography (EEG) as a non-invasive diagnostic tool.
UNASSIGNED: This review assesses advancements in EEG analysis, including the application of machine learning, for detecting AD from 2000 to 2023.
UNASSIGNED: Following PRISMA guidelines, a search across major databases resulted in 25 studies that met the inclusion criteria, focusing on EEG\'s application in AD diagnosis and the use of novel signal processing and machine learning techniques.
UNASSIGNED: Progress in EEG analysis has shown promise for early AD identification, with techniques like Hjorth parameters and signal compressibility enhancing detection capabilities. Machine learning has improved the precision of differential diagnosis between AD and mild cognitive impairment. However, challenges in standardizing EEG methodologies and data privacy remain.
UNASSIGNED: EEG stands out as a valuable tool for early AD detection, with the potential to integrate into multimodal diagnostic approaches. Future research should aim to standardize EEG procedures and explore collaborative, privacy-preserving research methods.

BACKGROUND: Motoric cognitive risk syndrome (MCR) is defined as the presence of slow gait-speed and subjective cognitive decline in older individuals without mobility disability or dementia. While some studies suggest that MCR is a pre-dementia syndrome and may help predict the risk of cognitive impairment and dementia, not all studies concur. The objective of this study is to comprehensively summarize and synthesize evidence to assess the association between MCR and cognitive impairment and dementia.
METHODS: Following a pre-specified protocol, two authors systematically searched PubMed, Embase, and The Cochrane Library from inception to 19 August 2024 for observational or randomized studies pertaining to the association between MCR and cognitive impairment and dementia. We favoured maximally adjusted hazards and odds ratios to determine the longitudinal and cross-sectional risk of cognitive impairment and dementia. We investigated for potential sources of heterogeneity and also conducted sensitivity and subgroup analyses by continent and the type of cognitive outcome. The quality of evidence was assessed using the Newcastle-Ottawa Scale (NOS) and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework.
RESULTS: We included 20 studies comprising a combined cohort of 1,206,782 participants, of which 17 studies were included in the quantitative analysis. The pooled analysis outlined that individuals with MCR exhibited 2.20-fold higher risk of cognitive impairment and dementia, compared to controls (RR=2.20; 95%CI=1.91-2.53). These findings remained robust across all subgroup analyses, sensitivity analyses and assessments of publication bias.
CONCLUSIONS: MCR may be considered a predictive factor for long-term cognitive impairment and dementia. This should be taken into consideration when clinically evaluating the risk of cognitive impairment and dementia but further research is required to lend greater clarity to this association.

Alzheimer\'s disease (AD) is one of the leading causes of dementia and is characterized by memory loss, mental and behavioral abnormalities, and impaired ability to perform daily activities. Even as a global disease that threatens human health, effective treatments to slow the progression of AD have not been found, despite intensive research and significant investment. In recent years, the role of infections in the etiology of AD has sparked intense debate. Pathogens invade the central nervous system through a damaged blood-brain barrier or nerve trunk and disrupt the neuronal structure and function as well as homeostasis of the brain microenvironment through a series of molecular biological events. In this review, we summarize the various pathogens involved in AD pathology, discuss potential interactions between pathogens and AD, and provide an overview of the promising future of anti-pathogenic therapies for AD.

UNASSIGNED: The largest identified kindred worldwide with a single mutation causing autosomal-dominant Alzheimer\'s disease (ADAD) is a family from Antioquia, Colombia, carrying the Presenilin-1 (PSEN1) E280A (Paisa) mutation. The majority of mutation carriers develop dementia, typically commencing in their late 30 s, with a median onset age of 49 years. Cognitive decline is a hallmark feature.
UNASSIGNED: This review synthesizes the existing literature on neuropsychological assessments in PSEN1 E280A mutation carriers throughout their lifespan. We provide a comprehensive overview of cognitive outcomes in this unique population.
UNASSIGNED: We reviewed and integrated the published research, analyzing studies on neuropsychological assessments in PSEN1 E280A carriers. Our focus was on measures of verbal, semantic, episodic, and spatial memory, and encompassed other cognitive domains such as language, attention, visuospatial memory, and executive functioning.
UNASSIGNED: Verbal, semantic, episodic, and spatial memory emerged as the most sensitive indicators of preclinical changes in PSEN1 E280A carriers. Inconsistencies were noted in findings from tests assessing language, attention, visuospatial memory, and executive functioning, suggesting potential limitations in detecting early cognitive changes in PSEN1 mutation carriers. Specific cognitive tasks developed for this population proved effective but underutilized.
UNASSIGNED: The review underscores the importance of continued test development tailored to detect early cognitive changes in PSEN1 E280A carriers, potentially enhancing ADAD screening. Furthermore, investigating ADAD mutations in children may identify early changes in AD and enhance our understanding of neuropsychological functioning across the lifespan. This synthesis provides valuable insights for researchers, clinicians, and policymakers engaged in the study and management of ADAD.

UNASSIGNED: Dementia is a major cause of disability and dependency globally. Mild cognitive impairment (MCI) is considered an early indicator of developing dementia. There are growing efforts to detect and diagnose MCI earlier; consequently, we need to understand the perspectives of individuals and carers regarding the implications of an MCI diagnosis.
UNASSIGNED: To systematically review qualitative literature to understand the impact of a MCI diagnosis on both the individual and their carers, focusing on wellbeing, everyday behaviors, and healthcare utilization.
UNASSIGNED: Key search terms were input into five databases. Studies were included if they were peer-reviewed qualitative research published in English that obtained perspectives of community-dwellers with MCI or carers and focused on either their wellbeing, everyday behaviors and/or healthcare utilization. The protocol was pre-registered on PROSPERO (CRD42021291995). Data was synthesized narratively.
UNASSIGNED: Key findings from 15 eligible articles highlighted the negative impact of an MCI diagnosis on the wellbeing of both individuals and carers, due to stigma and limited understanding regarding diagnosis/prognosis. Changes in everyday behavior varied, particularly regarding motivation to engage with physical activity, hobbies and social opportunities. Both individuals and carers were sometimes dissatisfied with healthcare services; ineffective communication during clinical consolations highlighted as a reason for lack of trust in clinicians.
UNASSIGNED: Results indicate that an MCI diagnosis impacts both people with MCI and their carers across key facets of life. There is a critical need to effectively communicate the diagnosis and prognosis of MCI to support wellbeing and everyday activities and ensure trust in healthcare services.

UNASSIGNED: Neurobiological changes in the hippocampus are a common consequence of aging. However, there are differences in the rate of decline and overall volume loss in people with no cognitive impairment compared to those with mild cognitive impairment (MCI) and Alzheimer\'s disease (AD). This systematic literature review was conducted to determine the relationship between hippocampal atrophy and changes in hippocampal volume in the non-cognitively impaired brain and those with MCI or AD.
UNASSIGNED: This systematic review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. The PubMed database was searched up to September 15, 2022, for longitudinal magnetic resonance imaging studies reporting hippocampal atrophy or volume change in cognitively normal aging individuals and patients with MCI and/or AD. Study selection was divided into two steps: (1) identification and retrieval of relevant studies; (2) screening the studies by (a) title/abstract and (b) full text. Two teams, each consisting of two independent reviewers, determined whether the publications met the inclusion criteria for the systematic review. An evidence table was populated with data extracted from eligible publications and inclusion in the final systematic review was confirmed.
UNASSIGNED: The systematic search identified 357 publications that were initially screened by title/abstract, of which, 115 publications were retrieved and reviewed by full text for eligibility. Seventeen publications met the eligibility criteria; however, during data extraction, two studies were determined to not meet the inclusion criteria and were excluded. The remaining 15 studies were included in the systematic review. Overall, the results of these studies demonstrated that the hippocampus and hippocampal subfields change over time, with both decreased hippocampal volume and increased rate of hippocampal atrophy observed. Hippocampal changes in AD were observed to be greater than hippocampal changes in MCI, and changes in MCI were observed to be greater than those in normal aging populations.
UNASSIGNED: Published literature suggests that the rate of hippocampal decline and extent of loss is on a continuum that begins in people without cognitive impairment and continues to MCI and AD, and that differences between no cognitive impairment, MCI, and AD are quantitative rather than qualitative.

Evidence shows that neurodegenerative and neuropsychiatric disorders are influenced by alterations in the gut microbiome. Various diseases have been linked to microbiome dysbiosis, yet there are inconclusive data regarding which microorganisms are associated with each disorder. The aim of our study is to systematically review the recent literature of the past decade to clarify whether the gut microbiome contributes to the understanding of pathogenesis and progression of neurodegenerative disorders. Most included studies showed a strong correlation between the relative abundance of certain microorganisms, mainly species of the phyla Firmicutes and Bacteroidetes, and disorders such as Parkinson\'s disease (PD) and Alzheimer\'s disease (AD). It is speculated that the microorganisms and their byproducts have a significant role in brain protein accumulation, neuro-inflammation, and gut permeability. The estimation of microbial populations could potentially improve clinical outcomes and hinder the progression of the disease. However, further research is needed to include more diseases and larger patient samples and identify specific species and subspecies associated with these disorders.

Alzheimer\'s disease is a weakening neurodegenerative condition with profound cognitive implications, making early and accurate detection crucial for effective treatment. In recent years, machine learning, particularly deep learning, has shown significant promise in detecting mild cognitive impairment to Alzheimer\'s disease conversion. This review synthesizes research on machine learning approaches for predicting conversion from mild cognitive impairment to Alzheimer\'s disease dementia using magnetic resonance imaging, positron emission tomography, and other biomarkers. Various techniques used in literature such as machine learning, deep learning, and transfer learning were examined in this study. Additionally, data modalities and feature extraction methods analyzed by different researchers are discussed. This review provides a comprehensive overview of the current state of research in Alzheimer\'s disease detection and highlights future research directions.

BACKGROUND: Monogenic Alzheimer\'s disease (AD) has severe health and socioeconomic repercussions. Its rarest cause is presenilin 2 (PSEN2) gene mutations. We present two new cases with presumed PSEN2-AD with unusual clinical and neuroimaging findings in order to provide more information on the pathophysiology and semiology of these patients.
METHODS: Women aged 69 and 62 years at clinical onset, marked by prominent behavioral and language dysfunction, progressing to severe dementia within three years were included. The complete study is depicted. In addition, a systematic review of the PSEN2-AD was performed.
RESULTS: Neuroimaging revealed pronounced frontal white matter hyperintensities (WMH) and frontotemporal atrophy/hypometabolism. The genetic study unveiled PSEN2 variants: c.772G>A (p.Ala258Thr) and c.1073-2_1073-1del. Both cerebrospinal fluid (CSF) and experimental blood biomarkers shouldered AD etiology.
CONCLUSIONS: Prominent behavioral and language dysfunction suggesting frontotemporal dementia (FTD) may be underestimated in the literature as a clinical picture in PSEN2 mutations. Thus, it may be reasonable to include PSEN2 in genetic panels when suspecting FTDL. PSEN2 mutations may cause striking WMH, arguably related to myelin disruption induced by amyloid accumulation.