Journal of Alzheimer's Disease - Volume 95, issue 3

Authors: Schork, Nicholas J. | Elman, Jeremy A.

Article Type: Research Article

Abstract: Background: APOE is the largest genetic risk factor for Alzheimer’s disease (AD), but there is a substantial polygenic component. Polygenic risk scores (PRS) can summarize small effects across the genome but may obscure differential risk across molecular processes and pathways that contribute to heterogeneity of disease presentation. Objective: We examined polygenic risk impacting specific AD-associated pathways and its relationship with clinical status and biomarkers of amyloid, tau, and neurodegeneration (A/T/N). Methods: We analyzed data from 1,411 participants from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). We applied pathway analysis and clustering to identify AD-associated “pathway clusters” …and construct pathway-specific PRSs (excluding the APOE region). We tested associations with diagnostic status, abnormal levels of amyloid and ptau, and hippocampal volume. Results: Thirteen pathway clusters were identified, and eight pathway-specific PRSs were significantly associated with AD diagnosis. Amyloid-positivity was associated with endocytosis and fibril formation, response misfolded protein, and regulation protein tyrosine PRSs. Ptau positivity and hippocampal volume were both related to protein localization and mitophagy PRS, and ptau-positivity was also associated with an immune signaling PRS. A global AD PRS showed stronger associations with diagnosis and all biomarkers compared to pathway PRSs. Conclusions: Pathway PRS may contribute to understanding separable disease processes, but do not add significant power for predictive purposes. These findings demonstrate that AD-phenotypes may be preferentially associated with risk in specific pathways, and defining genetic risk along multiple dimensions may clarify etiological heterogeneity in AD. This approach to delineate pathway-specific PRS can be used to study other complex diseases. Show more

Keywords: Alzheimer’s disease, amyloid, dementia, genetic risk score, hippocampal volume, tau

DOI: 10.3233/JAD-230548

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 915-929, 2023

Authors: Vassilaki, Maria | Fu, Sunyang | Christenson, Luke R. | Garg, Muskan | Petersen, Ronald C. | St. Sauver, Jennifer | Sohn, Sunghwan

Article Type: Research Article

Abstract: Background: Multiple algorithms with variable performance have been developed to identify dementia using combinations of billing codes and medication data that are widely available from electronic health records (EHR). If the characteristics of misclassified patients are clearly identified, modifying existing algorithms to improve performance may be possible. Objective: To examine the performance of a code-based algorithm to identify dementia cases in the population-based Mayo Clinic Study of Aging (MCSA) where dementia diagnosis (i.e., reference standard) is actively assessed through routine follow-up and describe the characteristics of persons incorrectly categorized. Methods: There were 5,316 participants (age at …baseline (mean (SD)): 73.3 (9.68) years; 50.7% male) without dementia at baseline and available EHR data. ICD-9/10 codes and prescription medications for dementia were extracted between baseline and one year after an MCSA dementia diagnosis or last follow-up. Fisher’s exact or Kruskal-Wallis tests were used to compare characteristics between groups. Results: Algorithm sensitivity and specificity were 0.70 (95% CI: 0.67, 0.74) and 0.95 (95% CI: 0.95, 0.96). False positives (i.e., participants falsely diagnosed with dementia by the algorithm) were older, with higher Charlson comorbidity index, more likely to have mild cognitive impairment (MCI), and longer follow-up (versus true negatives). False negatives (versus true positives) were older, more likely to have MCI, or have more functional limitations. Conclusions: We observed a moderate-high performance of the code-based diagnosis method against the population-based MCSA reference standard dementia diagnosis. Older participants and those with MCI at baseline were more likely to be misclassified. Show more

Keywords: Alzheimer’s disease, dementia, electronic health records, sensitivity, specificity

DOI: 10.3233/JAD-230344

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 931-940, 2023

Authors: Chen, Shanquan | Wang, Yuqi | Mueller, Christoph

Article Type: Article Commentary

Abstract: Code-based algorithms are crucial tools in the detection of dementia using electronic health record data, with broad applications in medical research and healthcare. Vassilaki et al.’s study explores the efficacy of code-based algorithms in dementia detection using electronic health record data, achieving approximately 70% sensitivity and positive predictive value. Despite the promising results, the algorithms fail to detect around 30% of dementia cases, highlighting challenges in distinguishing cognitive decline factors. The study emphasizes the need for algorithmic improvements and further exploration across diverse healthcare systems and populations, serving as a critical step toward bridging gaps in dementia care and understanding.

Keywords: Alzheimer’s disease, code-based algorithm, dementia, electronic health record

DOI: 10.3233/JAD-230887

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 941-943, 2023

Authors: Wang, Yaqi | Yang, Kai | Fu, Pengrui | Zheng, Xiaolei | Yang, Hui | Zhou, Qingbo | Ma, Wen | Wang, Ping

Article Type: Research Article

Abstract: Background: The ability to understand and make use of object-scene relationships are critical for object and scene recognition. Objective: The current study assessed whether patients with mild cognitive impairment (MCI), possibly in the preclinical phase of Alzheimer’s disease, exhibited impairment in processing contextual information in scene and object recognition. Methods: In Experiment 1, subjects viewed images of foreground objects in either semantic consistent or inconsistent scenes under no time pressure, and they verbally reported the names of foreground objects and backgrounds. Experiment 2 replicated Experiment 1, except that subjects were required to name scene first. Experiment …3 examined object and scene recognition accuracy baselines, recognition difficulty, familiarity with objects/scenes, and object-scene consistency judgements. Results: There were contextual consistency effects on scene recognition for MCI and healthy subjects, regardless of response sequence. Scenes were recognized more accurately under the consistent condition than the inconsistent condition. Additionally, MCI patients were more susceptible to incongruent contextual information, possibly due to inhibitory deficits or over-dependence on semantic knowledge. However, no significant differences between MCI and healthy subjects were observed in consistency judgement, recognition accuracy, recognition difficulty and familiarity rating, suggesting no significant impairment in object and scene knowledge among MCI subjects. Conclusions: The study indicates that MCI patients retain relatively intact contextual processing ability but may exhibit inhibitory deficits or over-reliance on semantic knowledge. Show more

Keywords: Alzheimer’s disease, contextual consistency, inhibitory deficits, mild cognitive impairment, object and scene recognition, over-reliance on semantic knowledge

DOI: 10.3233/JAD-221132

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 945-963, 2023

Authors: de Oliveira Otto, Marcia C. | Wu, Jason H.Y. | Thacker, Evan L. | Lai, Heidi Tsz Mung | Lemaitre, Rozenn N. | Padhye, Nikhil | Song, Xiaoling | King, Irena B. | Lopez, Oscar | Siscovick, David S. | Mozaffarian, Dariush

Article Type: Research Article

Abstract: Background: Comprising nearly 35% of brain lipids, polyunsaturated fatty acids (PUFA) are essential for optimal brain function. However, the role of PUFA on cognitive health outcomes later in life is largely unknown. Objective: We investigated prospective associations of plasma phospholipid omega-3 (ALA [18 : 3], EPA [20 : 5], DPA [22 : 5], DHA [22 : 6]) and omega-6 (LA [18 : 2], AA [20 : 4]) PUFA with cognitive decline, risk of cognitive impairment and dementia among adults aged≥65 years in the Cardiovascular Health Study. Methods: Circulating fatty acid concentrations were measured serially at baseline (1992/1993), 6 years, and 13 years later. Cognitive decline …and impairment were assessed using the 100-point Modified Mini-Mental State Examination (3MSE) up to 7 times. Clinical dementia was identified using adjudicated neuropsychological tests, and ICD-9 codes. Results: Among 3,564 older adults free of stroke and dementia at baseline, cognitive function declined annually by approximately -0.5 3MSE points; 507 participants developed cognitive impairment and 499 dementia over up to 23 years of follow-up. In multivariable models, higher circulating arachidonic acid (AA) concentrations were associated with slower cognitive decline and lower dementia risk, with associations growing stronger with greater length of follow-up (hazard ratio [HR,95% CI] of dementia per interquintile range, 0.74 [0.56-0.97] at 5 years, and 0.53 [0.37-0.77] at 15 years). Circulating docosapentaenoic (DPA) concentrations were associated with slower cognitive decline and lower risk of cognitive impairment (extreme-quintile HR, 0.72 [95% CI: 0.55, 0.95]). Findings were generally null or inconsistent for other omega-3 or omega-6 PUFA. Conclusion: Circulating AA and DPA, but not other PUFA, are associated with slower rate of cognitive decline and lower risk of dementia or cognitive impairment later in life. Show more

Keywords: Aging, Alzheimer’s disease, cognition, dementia, diet, fatty acids

DOI: 10.3233/JAD-230083

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 965-979, 2023

Authors: Jiang, Jiwei | Wang, Anxin | Liu, Yaou | Yao, Zeshan | Sun, Mengfan | Jiang, Tianlin | Li, Wenyi | Jiang, Shirui | Zhang, Xiaoli | Wang, Yanli | Zhang, Yuan | Jia, Ziyan | Zou, Xinying | Xu, Jun

Article Type: Research Article

Abstract: Background: Current technology for exploring neuroimaging markers and neural circuits of neuropsychiatric symptoms (NPS) in patients with Alzheimer’s disease (AD) is expensive and usually invasive, limiting its use in clinical practice. Objective: To investigate the cerebral morphology and perfusion characteristics of NPS and identify the spatiotemporal perfusion circuits of NPS sub-symptoms. Methods: This nested case-control study included 102 AD patients with NPS and 51 age- and sex-matched AD patients without NPS. Gray matter volume, cerebral blood flow (CBF), and arterial transit time (ATT) were measured and generated using time-encoded 7-delay pseudo-continuous arterial spin …labeling (pCASL). Multiple conditional logistic regression analysis was used to identify neuroimaging markers of NPS. The associations between the CBF or ATT of affected brain areas and NPS sub-symptoms were evaluated after adjusting for confounding factors. The neural circuits of sub-symptoms were identified based on spatiotemporal perfusion sequencing. Results: Lower Mini-Mental State Examination scores (p  < 0.001), higher Caregiver Burden Inventory scores (p  < 0.001), and higher CBF (p  = 0.001) and ATT values (p  < 0.003) of the right anteroventral thalamic nucleus (ATN) were risk factors for NPS in patients with AD. Six spatiotemporal perfusion circuits were found from 12 sub-symptoms, including the anterior cingulate gyri-temporal pole/subcortical thalamus-cerebellum circuit, insula-limbic-cortex circuit, subcortical thalamus-temporal pole-cortex circuit, subcortical thalamus-cerebellum circuit, frontal cortex-cerebellum-occipital cortex circuit, and subcortical thalamus-hippocampus-dorsal raphe nucleus circuit. Conclusions: Prolonged ATT and increased CBF of the right ATN may be neuroimaging markers for detecting NPS in patients with AD. Time-encoded pCASL could be a reliable technique to explore the neural perfusional circuits of NPS. Show more

Keywords: Alzheimer’s disease, neuroimaging, neuropsychiatric symptoms, perfusion

DOI: 10.3233/JAD-230499

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 981-993, 2023

Authors: Abyadeh, Morteza | Yadav, Vijay K. | Kaya, Alaattin

Article Type: Research Article

Abstract: Background: Cognitive decline is a common consequence of COVID-19, and studies suggest a link between COVID-19 and Alzheimer’s disease (AD). However, the molecular mechanisms underlying this association remain unclear. Objective: To understand the potential molecular mechanisms underlying the association between COVID-19 and AD development, and identify the potential genetic targets for pharmaceutical approaches to reduce the risk or delay the development of COVID-19-related neurological pathologies. Methods: We analyzed transcriptome datasets of 638 brain samples using a novel Robust Rank Aggregation method, followed by functional enrichment, protein-protein, hub genes, gene-miRNA, and gene-transcription factor (TF) …interaction analyses to identify molecular markers altered in AD and COVID-19 infected brains. Results: Our analyses of frontal cortex from COVID-19 and AD patients identified commonly altered genes, miRNAs and TFs. Functional enrichment and hub gene analysis of these molecular changes revealed commonly altered pathways, including downregulation of the cyclic adenosine monophosphate (cAMP) signaling and taurine and hypotaurine metabolism, alongside upregulation of neuroinflammatory pathways. Furthermore, gene-miRNA and gene-TF network analyses provided potential up- and downstream regulators of identified pathways. Conclusion: We found that downregulation of cAMP signaling pathway, taurine metabolisms, and upregulation of neuroinflammatory related pathways are commonly altered in AD and COVID-19 pathogenesis, and may make COVID-19 patients more susceptible to cognitive decline and AD. We also identified genetic targets, regulating these pathways that can be targeted pharmaceutically to reduce the risk or delay the development of COVID-19-related neurological pathologies and AD. Show more

Keywords: Alzheimer’s disease, cAMP signaling pathway, COVID-19, inflammation, omics, taurine and hypotaurine metabolism

DOI: 10.3233/JAD-230684

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 995-1011, 2023

Authors: Daamen, Marcel | Scheef, Lukas | Li, Shumei | Grothe, Michel J. | Gaertner, Florian C. | Buchert, Ralph | Buerger, Katharina | Dobisch, Laura | Drzezga, Alexander | Essler, Markus | Ewers, Michael | Fliessbach, Klaus | Herrera Melendez, Ana Lucia | Hetzer, Stefan | Janowitz, Daniel | Kilimann, Ingo | Krause, Bernd Joachim | Lange, Catharina | Laske, Christoph | Munk, Matthias H. | Peters, Oliver | Priller, Josef | Ramirez, Alfredo | Reimold, Matthias | Rominger, Axel | Rostamzadeh, Ayda | Roeske, Sandra | Roy, Nina | Scheffler, Klaus | Schneider, Anja | Spottke, Annika | Spruth, Eike Jakob | Teipel, Stefan J. | Wagner, Michael | Düzel, Emrah | Jessen, Frank | Boecker, Henning

Article Type: Research Article

Abstract: Background: Atrophy of cholinergic basal forebrain (BF) nuclei is a frequent finding in magnetic resonance imaging (MRI) volumetry studies that examined patients with prodromal or clinical Alzheimer’s disease (AD), but less clear for individuals in earlier stages of the clinical AD continuum. Objective: To examine BF volume reductions in subjective cognitive decline (SCD) participants with AD pathologic changes. Methods: The present study compared MRI-based BF volume measurements in age- and sex-matched samples of N = 24 amyloid-positive and N = 24 amyloid-negative SCD individuals, based on binary visual ratings of Florbetaben positron emission tomography (PET) measurements. Additionally, …we assessed associations of BF volume with cortical amyloid burden, based on semiquantitative Centiloid (CL) analyses. Results: Group differences approached significance for BF total volume (p  = 0.061) and the Ch4 subregion (p  = 0.059) only, showing the expected relative volume reductions for the amyloid-positive subgroup. There were also significant inverse correlations between BF volumes and CL values, which again were most robust for BF total volume and the Ch4 subregion. Conclusions: The results are consistent with the hypothesis that amyloid-positive SCD individuals, which are considered to represent a transitional stage on the clinical AD continuum, already show incipient alterations of BF integrity. The negative association with a continuous measure of cortical amyloid burden also suggests that this may reflect an incremental process. Yet, further research is needed to evaluate whether BF changes already emerge at “grey zone” levels of amyloid accumulation, before amyloidosis is reliably detected by PET visual readings. Show more

Keywords: Acetylcholine, Alzheimer’s disease, amyloid, atrophy, basal forebrain, cognitive decline

DOI: 10.3233/JAD-230141

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1013-1028, 2023

Authors: Camarillo, Joe | Villarreal Rizzo, Alan | Cabrero Castro, Jose Eduardo | Downer, Brian

Article Type: Research Article

Abstract: Background: The prevalence of type 2 diabetes in Mexico has nearly doubled for adults aged ≥60. Increases in education and healthcare resources to manage chronic conditions have contributed to population-level increases in the cognitive functioning of older adults. However, research has not focused on older adults with chronic conditions such as diabetes. Objective: Our objective was to compare the cognitive functioning of Mexican adults aged ≥60 with diabetes in 2001 and 2018. Methods: Data came from Mexican Health and Aging Study. Our study used a cross-sectional design and included participants aged ≥60 with …self-reported diabetes during the 2001 (n  = 1,052, mean age = 68.4, female = 59.6%) and 2018 (n  = 2,469, mean age = 70.6, female = 62.0%) observation waves. Five cognitive tests were used to create a score of global cognition. Generalized estimating equations were used to compare global cognition in 2001 to 2018. Results: Older adults in 2018 had more education and were more likely than older adults in 2001 to take oral medication for diabetes, insulin, and to check blood sugar weekly. Older adults in 2018 had higher global cognition than in 2001 when adjusting for age, gender, education, and health insurance coverage (b  = 0.38, SE = 0.02). This statistically significant difference remained after adjusting for health conditions, health behaviors, and diabetes management behaviors. Conclusions: Older adults in Mexico with self-reported diabetes in 2018 had higher cognitive function than in 2001. Future research is needed to investigate causes of the cohort differences in cognitive functioning among Mexican older adults with self-reported diabetes. Show more

Keywords: Alzheimer’s disease, cognition, diabetes mellitus, epidemiology, Mexico

DOI: 10.3233/JAD-230286

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1029-1039, 2023

Authors: Al-Lahham, Rabab | Mendez, Nicolas

Article Type: Research Article

Abstract: Background: Several epidemiological data revealed an association between Alzheimer’s disease (AD) and type 2 diabetes. Researchers concentrated on brain insulin resistance with little emphasis on the link between systemic insulin resistance and AD, despite the fact that the incidence of type 2 diabetes is higher in AD patients and that impairment in insulin signaling is a risk factor for AD. Objective: The goal of this study is to determine the role of systemic insulin resistance in the pathogenesis of Alzheimer’s disease by evaluating the consequences of tau loss-of-function on peripheral insulin sensitivity. Methods: …Primary hepatocytes isolated from transgenic mouse models (Tau KO, P301 L) and wild type mice (C57BL/6) were evaluated for their insulin sensitivity using glucose uptake assays as well as biochemical analysis of insulin signaling markers. Results: Our data show that tau deletion or loss of function promotes peripheral insulin resistance as seen in primary hepatocytes isolated from Tau KO and P301 L mice, respectively. Furthermore, exposure of wild-type primary hepatocytes to sub-toxic concentrations of tau oligomers results in a dose-dependent inhibition of glucose uptake, associated with downregulation of insulin signaling. Tau oligomers-induced inactivation of insulin signaling proteins was rescued by inhibition of p38 MAPK, suggesting the involvement of p38 MAPK. Conclusions: This is the first study testing tau role in peripheral insulin resistance at the cellular level using multiple transgenic mouse models. Moreover, this study suggests that tau should be functional for insulin sensitivity, therefore, any loss of function by deletion or aggregation would result in insulin resistance. Show more

Keywords: Alzheimer’s disease, AKT, GLUT4, GSK3β , insulin resistance, IRS1, p38 MAPK, tau oligomers

DOI: 10.3233/JAD-230392

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1041-1058, 2023

Authors: Costa, Tommaso | Premi, Enrico | Liloia, Donato | Cauda, Franco | Manuello, Jordi

Article Type: Research Article

Abstract: Background: Clinical trials targeting Alzheimer’s disease (AD) aim to alleviate clinical symptoms and alter the course of this complex neurodegenerative disorder. However, the conventional approach of null hypothesis significance testing (NHST) commonly employed in such trials has inherent limitations in assessing clinical significance and capturing nuanced evidence of effectiveness on a continuous scale. Objective: In this study, we conducted a re-analysis of the phase III trial of lecanemab, a recently proposed humanized IgG1 monoclonal antibody with high affinity for Aβ soluble protofibrils, using a Bayesian approach with informed t-test priors. Methods: To achieve …this, we carefully selected trial data and derived effect size estimates for the primary endpoint, the Clinical Dementia Rating Scale-Sum of Boxes (CDR-SB). Subsequently, a series of Bayes Factor analyses were performed to compare evidence supporting the null hypothesis (no treatment effect) versus the alternative hypothesis (presence of an effect). Drawing on relevant literature and the lecanemab phase III trial, we incorporated different minimal clinically important difference (MCID) values for the primary endpoint CDR-SB as prior information. Results: Our findings, based on a standard prior, revealed anecdotal evidence favoring the null hypothesis. Additional robustness checks yielded consistent results. However, when employing informed priors, we observed varying evidence across different MCID values, ultimately indicating no support for the effectiveness of lecanemab over placebo. Conclusion: Our study underscores the value of Bayesian analysis in clinical trials while emphasizing the importance of incorporating MCID and effect size granularity to accurately assess treatment efficacy. Show more

Keywords: Alzheimer’s disease, Bayes Factor, Clarity AD, clinical trial, drug development, informed t priors

DOI: 10.3233/JAD-230589

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1059-1065, 2023

Authors: Di Gioia, Claudia | Santonico, Marco | Zompanti, Alessandro | Sabatini, Anna | Grasso, Simone | Ursini, Francesca | Pedone, Claudio | Galdi, Flavia | Antonelli Incalzi, Raffaele | Pennazza, Giorgio

Article Type: Research Article

Abstract: Background: Recent studies have shown that oxidative stress plays a relevant role in Alzheimer’s disease (AD), and in the pathogenesis of vascular dementia (VaD). New diagnostic methods look for biological samples with non-invasive sampling methods. Among these, saliva shows an increase in oxidative stress products, thus a corresponding reduction in antioxidant products were found in dementia cases compared to healthy controls. Compounds identified in saliva include some hydrocarbons whose production has been related to the presence of reactive oxygen species. Objective: The hypothesis is that the voltammetric analysis performed on saliva could be a useful test for diagnosing …dementia, potentially discriminating between AD and VaD. Methods: A single-center observational study was conducted on patients referred to the dementia clinic in the Neurology area and healthy controls recruited in the Orthopedics area of the Campus Bio-Medico Hospital in Rome. The study was aimed at evaluating the discriminative properties of salivary voltammetric analysis between healthy subjects and patients with dementia and, as a secondary outcome, between AD and VaD. A total of 69 subjects were enrolled, including 29 healthy controls, 20 patients with AD, and 20 patients with VaD. The degree of cognitive impairment was classified on the basis of the Mini-Mental State Examination score. Results: The results obtained are promising, with an accuracy of 79.7%, a sensitivity of 82.5%, and a specificity of 75.8%, in the discrimination of dementia versus controls. Conclusions: The methods tested demonstrate to be relevant in the discrimination between dementia and controls. A confirmatory study is already running. Show more

Keywords: Alzheimer’s disease, cyclic voltammetry, dementia, multivariate data analysis, saliva fingerprint, vascular dementia

DOI: 10.3233/JAD-230330

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1067-1075, 2023

Authors: Li, Jinghang | Mountz, Elizabeth J. | Mizuno, Akiko | Shah, Ashti M. | Weinstein, Andrea | Cohen, Ann D. | Klunk, William E. | Snitz, Beth E. | Aizenstein, Howard J. | Karim, Helmet T.

Article Type: Research Article

Abstract: Background: Amyloid-β (Aβ) deposits asymmetrically early in Alzheimer’s disease (AD). This process is variable and has been associated with asymmetric hypometabolism. Objective: We investigated whether neural asymmetry during working memory and executive function processing was associated with AD genetic risk and markers of AD as well as other brain neuropathology biomarkers, cognitive function, and cognitive reserve in cognitively normal older adults. Methods: We analyzed data from 77 cognitively healthy, older adults who completed functional magnetic resonance imaging, positron emission tomography, and cognitive testing. We identified regions of significant activation and asymmetry during the Digital Symbol Substitution …Task (DSST). We examined associations between regions with significant hemispheric asymmetry (directional and absolute) and global cerebral Aβ, cerebral glucose metabolism, white matter hyperintensities, APOE ɛ4 allele status, DSST reaction time, age, sex, education, and cognitive function. Results: Asymmetry was not associated with several factors including cognitive function, Aβ, and white matter hyperintensities. The presence of at least one ɛ4 APOE allele in participants was associated with less asymmetric activation in the angular gyrus (right dominant activation). Greater education was associated with less asymmetric activation in mediodorsal thalamus (left dominant activation). Conclusions: Genetic risk of AD was associated with lower asymmetry in angular gyrus activation, while greater education was associated with lower asymmetry in mediodorsal thalamus activation. Changes in asymmetry may reflect components of compensation or cognitive reserve. Asymmetric neural recruitment during working memory may be related to maintenance of cognitive function in cognitively normal older adults. Show more

Keywords: Alzheimer’s disease, amyloid, asymmetry, functional brain activation, preclinical Alzheimer’s disease, working memory

DOI: 10.3233/JAD-230379

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1077-1089, 2023

Authors: Ramos, Claudia | Madrigal, Claudia | Aguirre-Acevedo, Daniel Camilo | Giraldo-Chica, Margarita | Acosta-Baena, Natalia | Aponte, Claudia | Aguillón, David | Gómez, Manuela | Espinosa, Alejandro | Madrigal, Lucia | Uribe, Claramonika | Saldarriaga, Amanda | Alzate, Diana | Ruiz, Alejandra | Andrade, Angela | Lopez, Hugo | Langbaum, Jessica B. | Sink, Kaycee M. | Reiman, Eric M. | Tariot, Pierre N. | Ríos-Romenets, Silvia | Lopera, Francisco

Article Type: Research Article

Abstract: Background: The SARS-CoV2 global pandemic impacted participants in the Alzheimer’s Prevention Initiative (API) Autosomal Dominant Alzheimer’s Disease (ADAD) clinical trial, who faced three stressors: 1) fear of developing dementia; 2) concerns about missing treatment; and 3) risk of SARS-CoV2 infection. Objective: To describe the frequency of psychological disorders among the participants of the API ADAD Colombia clinical study, treated by a holistic mental health team during the COVID-19 pandemic. The extent of use of mental health team services was explored considering different risk factors, and users and non-users of these services were compared. Methods: Participants had …free and optional access to psychology and psychiatry services, outside of the study protocol. Descriptive statistics was used to analyze the frequency of the mental health difficulties. A multivariable logistic regression model has been used to assess associations with using this program. Results: 66 participants were treated by the Mental Health Team from March 1, 2020, to December 31, 2020. Before and after the start of the pandemic, the most common psychological problems were anxiety (36.4% before, 63.6% after) and depression (34.8% before, 37.9% after). 70% of users assisted by psychology and 81.6% of those assisted by psychiatry felt that the services were useful for them. Female sex, depression, and anxiety before the pandemic were positively associated with being assisted by either psychology or psychiatry, while the association with hyperlipidemia was negative. Conclusions: A holistic mental health program, carried out in the context of a study, could mitigate psychopathology during pandemics such as COVID-19. Show more

Keywords: Alzheimer’s disease, COVID-19, health services and institutions

DOI: 10.3233/JAD-220941

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1091-1106, 2023

Authors: Uchida, Yuto | Onda, Kengo | Hou, Zhipeng | Troncoso, Juan C. | Mori, Susumu | Oishi, Kenichi

Article Type: Research Article

Abstract: Background: Conventional neuroimaging biomarkers for the neurodegeneration of Alzheimer’s disease (AD) are not sensitive enough to detect neurodegenerative alterations during the preclinical stage of AD individuals. Objective: We examined whether neurodegeneration of the entorhinal-hippocampal pathway could be detected along the AD continuum using ultra-high-field diffusion tensor imaging and tractography for ex vivo brain tissues. Methods: Postmortem brain specimens from a cognitively unimpaired individual without AD pathological changes (non-AD), a cognitively unimpaired individual with AD pathological changes (preclinical AD), and a demented individual with AD pathological changes (AD dementia) were scanned with an …11.7T diffusion magnetic resonance imaging. Fractional anisotropy (FA) values of the entorhinal layer II and number of perforant path fibers counted by tractography were compared among the AD continuum. Following the imaging analyses, the status of myelinated fibers and neuronal cells were verified by subsequent serial histological examinations. Results: At 250μm (zipped to 125μm) isotropic resolution, the entorhinal layer II islands and the perforant path fibers could be identified in non-AD and preclinical AD, but not in AD dementia, followed by histological verification. The FA value of the entorhinal layer II was the highest among the entorhinal laminae in non-AD and preclinical AD, whereas the FA values in the entorhinal laminae were homogeneously low in AD dementia. The FA values and number of perforant path fibers decreased along the AD continuum (non-AD>preclinical AD > AD dementia). Conclusion: We successfully detected neurodegenerative alterations of the entorhinal-hippocampal pathway at the preclinical stage of the AD continuum. Show more

Keywords: Alzheimer’s disease, diffusion tensor imaging, entorhinal cortex, fiber tractography, histology, magnetic resonance imaging, neurodegeneration

DOI: 10.3233/JAD-230452

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1107-1117, 2023

Authors: Serra, Laura | Bonarota, Sabrina | Di Domenico, Carlotta | Caruso, Giulia | Giulietti, Giovanni | Caltagirone, Carlo | Cercignani, Mara | Bozzali, Marco

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is the most common form of dementia worldwide. Currently there are no disease modifying treatments available. Detecting subjects with increased risk to develop dementia is essential for future clinical trials. Subjective cognitive decline (SCD) is a condition defining individuals who perceive a decrease in their own cognitive functioning in the absence of any detectable deficit on neuropsychological testing. SCD individuals show AD-related biomarkers abnormalities in cerebrospinal fluid. Objective: The aim of the present study was to assess brain functional connectivity (FC) changes in SCD individuals. Methods: 23 SCD and 33 healthy subjects …(HS) underwent an extensive neuropsychological assessment and 3T-MRI scanning including a T1-w volume and resting-state fMRI (RS-fMRI) to assess brain atrophy and brain FC. Results: No between-group differences in grey matter volumes were detected. SCD subjects compared to HS showed both increased and decreased FC in the executive and parietal networks. Associations between cognitive measures, mainly assessing working memory, and FC within brain networks were found both in SCD and HS separately. Conclusions: SCD individuals showed FC abnormalities in networks involving fronto-parietal areas that may account for their lower visuo-spatial working memory performances. Dysfunctions in executive-frontal networks may be responsible for the cognitive decline subjectively experienced by SCD individuals despite the normal scores observed by formal neuropsychological assessment. The present study contributes to consider SCD individuals in an early AD stage with an increased risk of developing the disease in the long term. Show more

Keywords: Alzheimer’s disease, brain functional connectivity, cognitive functions, magnetic resonance imaging, subjective cognitive decline

DOI: 10.3233/JAD-230536

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1119-1131, 2023

Authors: Ekenze, Oluchi | Pinheiro, Adlin | Demissie, Serkalem | Aparicio, Hugo J. | Charidimou, Andreas | Beiser, Alexa S. | Satizabal, Claudia L. | Kautz, Tiffany | DeCarli, Charles | Greenberg, Steven | Seshadri, Sudha | Romero, Jose R.

Article Type: Research Article

Abstract: Background: Neurofilament light chain (NfL) is a marker of neuronal injury. Perivascular spaces (PVS) visible on magnetic resonance imaging (MRI) represent cerebral small vessel disease (CSVD) but their role as markers of neuronal injury needs further clarification. Objective: To relate PVS burden according to brain topography and plasma NfL. Methods: Framingham Heart Study (FHS) participants with brain MRI and NfL measurements were included. PVS were rated in the basal ganglia (BG) and centrum semiovale (CSO) using validated methods and categorized based on counts. A mixed region variable representing high burden PVS in either BG or CSO …was assessed. Multivariable linear regression analyses were used to relate PVS burden to log-transformed NfL levels in models adjusted for age, sex, FHS cohort, time between MRI and clinic exam, and image view (model 1), vascular risk factors (model 2), and white matter hyperintensity volume, covert brain infarcts, and cerebral microbleeds (model 3). Results: Among 1,457 participants (68.1±8.5 years, 45% males), NfL levels increased with higher PVS burden. Multivariable analysis showed an association of high PVS burden strictly in BG with NfL (β= 0.117, 95% CI 0.014–0.221; p  = 0.027), but attenuated in model 3. The associations were mainly in participants≥65 years (β= 0.122, 95% CI 0.015–0.229, p  = 0.026), women (β= 0.156, 95% CI 0.024–0.288, p  = 0.021), and APOE ɛ4 non-carriers (β= 0.140, 95% CI 0.017–0.263, p  = 0.026). Conclusions: The association of strictly BG high PVS burden with NfL suggests a role for PVS as markers of neuroaxonal injury, but our results are hypothesis generating and require further replication. Show more

Keywords: Alzheimer’s disease, basal ganglia, cerebral small vessel disease, MRI visible perivascular spaces, neurofilament light chain, neuroaxonal injury

DOI: 10.3233/JAD-221260

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1133-1145, 2023

Authors: Hua, Simin | Peters, Brandilyn A. | Lee, Susie | Fitzgerald, Kathryn | Wang, Zheng | Sollecito, Christopher C. | Grassi, Evan | Wiek, Fanua | St Peter, Lauren | D’Souza, Gypsyamber | Weber, Kathleen M. | Kaplan, Robert C. | Gustafson, Deborah | Sharma, Anjali | Burk, Robert D. | Rubin, Leah H. | Qi, Qibin

Article Type: Research Article

Abstract: Background: Altered gut microbiota has been associated with cognitive dysfunction and Alzheimer’s disease, but little is known among people living with HIV. Objective: To examine associations between gut microbiota and cognitive impairment among women with or without HIV. Methods: This is a cross-sectional study of 446 women (302 HIV+) who had completed a neuropsychological test battery and stool sample collected within 1 year. Gut microbiota composition was quantified using 16SV4 rRNA gene sequencing and microbial functional pathways were predicted using PICRUSt. Cognitive domains included attention, executive function, learning, memory, fluency, processing speed, and motor function. Cognitive …impairment was defined as two or more domains with T scores < 1 SD below mean. ANCOM-II was used to identify taxa and functional pathways associated with cognitive impairment, and the associations were further examined by multivariable logistic regression. Results: In overall sample, adjusting for multiple covariates including HIV status, we found that higher abundance of Methanobrevibacter, Odoribacter, Pyramidobacter, Eubacterium, Ruminococcus , and Gemmiger , and lower abundance of Veillonella were associated with cognitive impairment. The associations between these taxa and cognitive impairment were more profound in HIV+ women compared to HIV- women. Most associations with bacterial taxa were observed for learning and memory. We found accompanying microbial functional differences associated with cognitive impairment, including twelve enriched pathways and three depleted pathways. Conclusions: In women with or without HIV infection, this study identified multiple altered gut bacterial taxa and functional pathways associated with cognitive impairment, supporting the potential role of gut microbiota in cognitive dysfunction and Alzheimer’s disease. Show more

Keywords: Alzheimer’s disease, cognitive impairment, gut microbiome, HIV, human, women

DOI: 10.3233/JAD-230117

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1147-1161, 2023

Authors: Makri, Marina | Gkioka, Mara | Moraitou, Despina | Fidani, Liana | Tegos, Thomas | Tsolaki, Magdalini

Article Type: Research Article

Abstract: Background: Pre-symptomatic screening methods for detecting a higher risk of Alzheimer’s disease (AD) are gaining popularity; thus, more people are seeking these tests. However, to date, not much is known about the attitudes toward pre-symptomatic AD screening. Objective: The goal of this study is to examine the psychometric properties of a tool for assessing the attitudes, barriers, and motivations to pre-symptomatic AD screening. Methods: This is a cross-sectional study performed on 208 Greek participants (189 students and 19 caregivers) provided with an online questionnaire. Psychometric properties were assessed through the examination of its construct validity (principal …component analysis) and internal consistency. Results: Exploratory factor analysis revealed the presence of four factors. The first factor is labeled as “Perceived harms of testing” (10 items), the second “Acceptance of testing” (5 items), the third “Perceived benefits of testing” (6 items), and the fourth factor “Need for knowledge” (4 items). The reliability (internal consistency) of each factor separately was acceptable to good (0.70–0.87) while the internal consistency of the overall questionnaire (25 items) was good (Cronbach’s α =0.82). Conclusion: PRE-ADS is a valid questionnaire that might help in the research of peoples’ attitudes related to the pros and cons of pre-symptomatic screening for AD, and the development of effective counseling programs and prevention strategies. However, future research is required in the target population. Show more

Keywords: Alzheimer’s disease, attitudes, benefits, perceived harms, pre-symptomatic testing, psychometrics, screening, screening acceptance, validation

DOI: 10.3233/JAD-220954

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1163-1174, 2023

Authors: Li, Zhigang | Wu, Hao | Ji, Yong | Shi, Zhihong | Liu, Shuai | Bao, Xinran | Shan, Peng | Hu, Dean | Li, Meimei

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease. The detection of early-stage AD is particularly desirable because it would allow early intervention. However, a minimally invasive, low-cost, and accurate discrimination or diagnostic method for AD is especially difficult in the earliest stage of AD. Objective: The aim of this research is to discover blood plasma spectral digital biomarkers of AD, develop a novel intelligent method for the discrimination of AD and accelerate the translation of Fourier transform infrared (FTIR) spectral-based disease discrimination methods from the laboratory to clinical practice. Methods: Since vibration spectroscopy can …provide the structure and chemical composition information of biological samples at the molecular level, we investigated the potential of FTIR spectral biomarkers of blood plasma to differentiate between AD patients and healthy controls. Combined with machine learning technology, we designed a hierarchical discrimination system that provides reagent-free and accurate AD discrimination based on blood plasma spectral digital biomarkers of AD. Results: Accurate segregation between AD patients and healthy controls was achieved with 89.3% sensitivity and 85.7% specificity for early-stage AD patients, 92.8% sensitivity and 87.5% specificity for middle-stage AD patients, and 100% sensitivity and 100% specificity for late-stage AD patients. Conclusions: Our results show that blood plasma spectral digital biomarkers hold great promise as discrimination markers of AD, indicating the potential for the development of an inexpensive, reagent-free, and less laborious clinical test. As a result, our research outcome will accelerate the clinical application of spectral digital biomarkers and machine learning. Show more

Keywords: Alzheimer’s disease, blood plasma, discrimination, machine learning, reagent-free, spectral digital biomarkers

DOI: 10.3233/JAD-230248

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1175-1188, 2023

Authors: Creavin, Samuel Thomas | Fish, Mark | Lawton, Michael | Cullum, Sarah | Bayer, Antony | Purdy, Sarah | Ben-Shlomo, Yoav

Article Type: Research Article

Abstract: Background: Many health systems are interested in increasing the number of uncomplicated and typical dementia diagnoses that are made in primary care, but the comparative accuracy of tests is unknown. Objective: Calculate diagnostic accuracy of brief cognitive tests in primary care. Methods: We did a diagnostic test accuracy study in general practice, in people over 70 years who had consulted their GP with cognitive symptoms but had no prior diagnosis of dementia. The reference standard was specialist assessment, adjudicated for difficult cases, according to ICD-10. We assessed 16 index tests at a research clinic, and additionally …analyzed referring GPs clinical judgement. Results: 240 participants had a median age of 80 years, of whom 126 were men and 132 had dementia. Sensitivity of individual tests at the recommended thresholds ranged from 56% for GP judgement (specificity 89%) to 100% for MoCA (specificity 16%). Specificity of individual tests ranged from 4% for Sniffin’ sticks (sensitivity 100%) to 91% for Timed Up and Go (sensitivity 23%). The 95% centile of test duration in people with dementia ranged from 3 minutes for 6CIT and Time and Change, to 16 minutes for MoCA. Combining tests with GP judgement increased test specificity and decreased sensitivity: e.g., MoCA with GP Judgement had specificity 87% and sensitivity 55%. Conclusions: Using GP judgement to inform selection of tests was an efficient strategy. Using IQCODE in people who GPs judge as having dementia and 6CIT in people who GPs judge as having no dementia, would be a time-efficient and accurate diagnostic assessment. The original protocol for the study is available at https://bmcfampract.biomedcentral.com/articles/10.1186/s12875-016-0475-2 Show more

Keywords: Alzheimer’s disease, dementia, general practice, sensitivity and specificity, symptom assessment

DOI: 10.3233/JAD-230320

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1189-1200, 2023

Authors: Zhang, Jingwen | Liu, Qing | Zhang, Haorui | Dai, Michelle | Song, Qianqian | Yang, Defu | Wu, Guorong | Chen, Minghan

Article Type: Research Article

Abstract: Background: Despite the striking efforts in investigating neurobiological factors behind the acquisition of amyloid-β (A), protein tau (T), and neurodegeneration ([N]) biomarkers, the mechanistic pathways of how AT[N] biomarkers spreading throughout the brain remain elusive. Objective: To disentangle the massive heterogeneities in Alzheimer’s disease (AD) progressions and identify vulnerable/critical brain regions to AD pathology. Methods: In this work, we characterized the interaction of AT[N] biomarkers and their propagation across brain networks using a novel bistable reaction-diffusion model, which allows us to establish a new systems biology underpinning of AD progression. We applied our model to large-scale …longitudinal neuroimages from the ADNI database and studied the systematic vulnerability and criticality of brains. Results: Our model yields long term prediction that is statistically significant linear correlated with temporal imaging data, produces clinically consistent risk prediction, and captures the Braak-like spreading pattern of AT[N] biomarkers in AD development. Conclusions: Our major findings include (i) tau is a stronger indicator of regional risk compared to amyloid, (ii) temporal lobe exhibits higher vulnerability to AD-related pathologies, (iii) proposed critical brain regions outperform hub nodes in transmitting disease factors across the brain, and (iv) comparing the spread of neuropathological burdens caused by amyloid-β and tau diffusions, disruption of metabolic balance is the most determinant factor contributing to the initiation and progression of AD. Show more

Keywords: Alzheimer’s disease, AT[N] biomarkers, brain network, reaction-diffusion model, vulnerable and critical regions

DOI: 10.3233/JAD-230027

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1201-1219, 2023

Authors: Oyarzún-González, Ximena | Abner, Erin L. | Toro, Pablo | Ferreccio, Catterina

Article Type: Research Article

Abstract: Background: Subjective memory complaints (SMC) are commonly studied in older adults and have been identified as potentially prodromal to dementia and Alzheimer’s disease. Studies among younger adults from South America are lacking. Objective: To estimate the prevalence of SMC and the factors associated with it among Maule Cohort (MAUCO) participants. Methods: We performed a cross-sectional analysis to estimate the prevalence of SMC and investigated its associated factors from MAUCO baseline data (N = 6,687). Within groups defined by age (38–59, 60–74) and global cognition (Mini-Mental State Examination: ≥26, 25-22, ≤21), multinomial logistic regression models evaluated risk factors for …SMC (Yes, Sometimes, No). Results: Overall, SMC prevalence was 16.4%; 15.9% (95% CI 14.9–16.9%) among younger and 17.6% (15.8–19.4%) among older participants. Female sex, comorbidities, and bad/fair self-reported health status (SRHS) were generally associated with higher odds of SMC. Conclusion: Overall prevalence of SMC was 16%. Different factors were associated with the odds of SMC depending on age and global cognitive status. Future SMC studies should include sex-specific assessments, evaluate SRHS as a moderator of SMC reporting, and the influence of the SARS-CoV-2 pandemic on SMC reporting. Show more

Keywords: Alzheimer’s disease, cohort, MAUCO, memory, multinomial, subjective memory complaint

DOI: 10.3233/JAD-230541

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1221-1231, 2023

Authors: Koppelmans, Vincent | Ruitenberg, Marit F.L. | Schaefer, Sydney Y. | King, Jace B. | Hoffman, John M. | Mejia, Amanda F. | Tasdizen, Tolga | Duff, Kevin

Article Type: Research Article

Abstract: Background: Despite reports of gross motor problems in mild cognitive impairment (MCI) and Alzheimer’s disease (AD), fine motor function has been relatively understudied. Objective: We examined if finger tapping is affected in AD, related to AD biomarkers, and able to classify MCI or AD. Methods: Forty-seven cognitively normal, 27 amnestic MCI, and 26 AD subjects completed unimanual and bimanual computerized tapping tests. We tested 1) group differences in tapping with permutation models; 2) associations between tapping and biomarkers (PET amyloid-β, hippocampal volume, and APOE ɛ 4 alleles) with linear regression; and 3) the predictive value …of tapping for group classification using machine learning. Results: AD subjects had slower reaction time and larger speed variability than controls during all tapping conditions, except for dual tapping. MCI subjects performed worse than controls on reaction time and speed variability for dual and non-dominant hand tapping. Tapping speed and variability were related to hippocampal volume, but not to amyloid-β deposition or APOE ɛ 4 alleles. Random forest classification (overall accuracy = 70%) discriminated control and AD subjects, but poorly discriminated MCI from controls or AD. Conclusions: MCI and AD are linked to more variable finger tapping with slower reaction time. Associations between finger tapping and hippocampal volume, but not amyloidosis, suggest that tapping deficits are related to neuropathology that presents later during the disease. Considering that tapping performance is able to differentiate between control and AD subjects, it can offer a cost-efficient tool for augmenting existing AD biomarkers. Show more

Keywords: Alzheimer’s disease, biomarkers, finger tapping, manual dexterity, motor function

DOI: 10.3233/JAD-221297

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1233-1252, 2023

Authors: Fazlollahi, Amir | Lee, Soohyun | Coleman, Felicia | McCann, Emily | Cloos, Martijn A. | Bourgeat, Pierrick | Nestor, Peter J.

Article Type: Research Article

Abstract: Background: Objective measurement of regional cortical atrophy in individual patients would be a highly desirable adjunct for diagnosis of degenerative dementias. Objective: We hypothesized that increasing the resolution of magnetic resonance scans would improve the sensitivity of cortical atrophy detection for individual patients. Methods: 46 participants including 8 semantic-variant primary progressive aphasia (svPPA), seven posterior cortical atrophy (PCA), and 31 cognitively unimpaired participants underwent clinical assessment and 3.0T brain scans. SvPPA and PCA were chosen because there is overwhelming prior knowledge of the expected atrophy pattern. Two sets of T1-weighted images with 0.8 mm3 (HighRes) …and conventional 1.0 mm3 (ConvRes) resolution were acquired. The cortical ribbon was segmented using FreeSurfer software to obtain surface-based thickness maps. Inter-sequence performance was assessed in terms of cortical thickness and sub-cortical volume reproducibility, signal-to-noise and contrast-to-noise ratios. For clinical cases, diagnostic effect size (Cohen’s d) and lesion distribution (z-score and t-value maps) were compared between HighRes and ConvRes scans. Results: The HighRes scans produced higher image quality scores at 90 seconds extra scan time. The effect size of cortical thickness differences between patients and cognitively unimpaired participants was 15–20% larger for HighRes scans. HighRes scans showed more robust patterns of atrophy in expected regions in each and every individual patient. Conclusions: HighRes T1-weighted scans showed superior precision for identifying the severity of cortical atrophy in individual patients, offering a proof-of-concept for clinical translation. Studying svPPA and PCA, two syndromes with well-defined focal atrophy patterns, offers a method to clinically validate and contrast automated algorithms. Show more

Keywords: Alzheimer’s disease, atrophy, cortical thickness, degeneration, dementia, dementia diagnosis, MPRAGE

DOI: 10.3233/JAD-230030

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1253-1262, 2023

Authors: Kim, Dong-Yun | Kim, Jae Sik | Seo, Young-Seok | Park, Woo-Yoon | Kim, Byoung Hyuck | Hong, Eun-Hee | Kim, Ji Young | Cho, Seong-Jun | Rhee, Hak Young | Kim, Aryun | Kim, Keun You | Oh, Dae Jong | Chung, Weon Kuu

Article Type: Research Article

Abstract: Background: Alzheimer’s disease (AD), the most common cause of dementia, is a neurodegenerative disease resulting from extracellular and intracellular deposits of amyloid-β (Aβ) and neurofibrillary tangles in the brain. Although many clinical studies evaluating pharmacological approaches have been conducted, most have shown disappointing results; thus, innovative strategies other than drugs have been actively attempted. Objective: This study aims to explore low-dose radiation therapy (LDRT) for the treatment of patients with AD based on preclinical evidence, case reports, and a small pilot trial in humans. Methods: This study is a phase II, multicenter, prospective, …single-blinded, randomized controlled trial that will evaluate the efficacy and safety of LDRT to the whole brain using a linear accelerator in patients with mild AD. Sixty participants will be randomly assigned to three groups: experimental I (24 cGy/6 fractions), experimental II (300 cGy/6 fractions), or sham RT group (0 cGy/6 fractions). During LDRT and follow-up visits after LDRT, possible adverse events will be assessed by the physician’s interview and neurological examinations. Furthermore, the effectiveness of LDRT will be measured using neurocognitive function tests and imaging tools at 6 and 12 months after LDRT. We will also monitor the alterations in cytokines, Aβ42 /Aβ40 ratio, and tau levels in plasma. Our primary endpoint is the change in cognitive function test scores estimated by the Alzheimer’s Disease Assessment Scale-Korea compared to baseline after 6 months of LDRT. Conclusions: This study is registered at ClinicalTrials.gov [NCT05635968] and is currently recruiting patients. This study will provide evidence that LDRT is a new treatment strategy for AD. Show more

Keywords: Alzheimer’s disease, low-dose radiation therapy, protocol, randomized controlled trial

DOI: 10.3233/JAD-230241

Citation: Journal of Alzheimer's Disease, vol. 95, no. 3, pp. 1263-1272, 2023