Tom Shea and Ben Szaro
In Memoriam: Harish Chandra Pant
John Paul Ross, Stephen G. Post, Laurel Scheinfeld
Lucidity in the Deeply Forgetful: A Scoping Review
Abstract: Background: Even in severe states of Alzheimer’s disease and related dementias (ADRD), accounts of an unexpected or paradoxical return of awareness and lucidity have been reported in some patients, documented formally, and studied. Objective: A scoping review was undertaken to survey the literature on the topic. Methods: Five databases were searched using pertinent search terms. Results were deduplicated and subsequently screened by title and abstract for relevance. Remaining reports were read and included or excluded using specific inclusion criteria. 30 results consisted of a mix of perspective papers, case reports, qualitative surveys of caregivers, law journal comments, and mechanistic speculation. Results: An equal mix of primary and secondary research was identified. Conclusions: The papers collected in this review provide a valuable methodological outline for researching the topic of lucid episodes in ADRD. The verified legitimacy and simultaneous inexplicability of these events promote philosophical discussion, mechanistic investigations, and sorely needed research in the field of ADRD.
Zhirui Li, Zixuan Fan, Qian Zhang
The Associations of Phosphorylated Tau 181 and Tau 231 Levels in Plasma and Cerebrospinal Fluid with Cognitive Function in Alzheimer’s Disease: A Systematic Review and Meta-Analysis
Abstract: Background: Cerebrospinal fluid (CSF) or blood biomarkers like phosphorylated tau proteins (p-tau) are used to detect Alzheimer's disease (AD) early. Increasing studies on cognitive function and blood or CSF p-tau levels are controversial. Objective: Our study examined the potential of p-tau as a biomarker of cognitive status in normal control (NC), mild cognitive impairment (MCI), and AD patients. Methods: We searched PubMed, Cochrane, Embase, and Web of Science for relevant material through 12 January 2023. 5,017 participants from 20 studies—1,033 AD, 2,077 MCI, and 1,907 NC—were evaluated. Quantitative analysis provided continuous outcomes as SMDs with 95% CIs. Begg tested publication bias. Results: MCI patients had lower CSF p-tau181 levels than AD patients (SMD = -0.60, 95% CI (-0.85, -0.36)) but higher than healthy controls (SMD = 0.67). AD/MCI patients had greater plasma p-tau181 levels than healthy people (SMD = -0.73, 95% CI (-1.04, -0.43)). MCI patients had significantly lower p-tau231 levels than AD patients in plasma and CSF (SMD = -0.90, 95% CI (-0.82, -0.45)). MCI patients showed greater CSF and plasma p-tau231 than healthy controls (SMD = 1.34, 95% CI (0.89, 1.79) and 0.43, (0.23, 0.64)). Plasma p-tau181/231 levels also distinguished the three categories. MCI patients had higher levels than healthy people, while AD patients had higher levels than MCI patients. Conclusions: CSF p-tau181 and p-tau231 biomarkers distinguished AD, MCI, and healthy populations. Plasma-based p-tau181 and p-tau231 biomarkers for AD and MCI need further study.
Eleonora Rossi, Francesco Marrosu, Luca Saba
Music Therapy as a Complementary Treatment in Patients with Dementia Associated to Alzheimer’s Disease: A Systematic Review
Abstract: Background: Alzheimer's disease (AD) is a complex condition that affects various aspects of a patient's life. Music therapy may be considered a beneficial supplementary tool to traditional therapies, that not fully address the range of AD manifestations. Objective: The purpose of this systematic review is to investigate whether music therapy can have a positive impact on AD patients and on which symptoms. Methods: The main research databases employed have been PubMed and Cochrane, using the keywords “dementia”, “music therapy”, “Alzheimer”, "fMRI", "music", and "EEG". Results: After removing duplicates and irrelevant studies, 23 were screened using set criteria, resulting in the final inclusion of 15 studies. The total number of participants included in these studies has been of 1,196 patients. For the fMRI analysis the search resulted in 28 studies on PubMed, two of which were included in the research; the total number of participants was of 124 individuals. The studies conducted with EEG were found using PubMed. The initial search resulted in 15 studies, but after a more accurate evaluation only 2 have been included in the analysis. Conclusions: Even though the data currently available is not sufficient to draw conclusions supported by robust statistical power, the impact of music therapy on AD neuropsychiatric symptoms deserves great interest. Further research should be ushered, possibly multicentric studies, led with neuroimaging and other recent techniques, which can eventually open views on the music role in improving the cognitive status in AD.
Matteo Cotta Ramusino, Lucia Scanu, Linda Gritti, Camillo Imbimbo, Lisa Maria Farina, Giuseppe Cosentino, Giulia Perini, Alfredo Costa
Neurophysiological Alterations of the Visual Pathway in Posterior Cortical Atrophy: Systematic Review and a Case Series
Abstract: Background: The clinical features of posterior cortical atrophy (PCA), a rare condition often caused by Alzheimer’s disease, have been recently defined, while little is known about its neurophysiological correlates. Objective: To describe neurophysiological alterations of the visual pathway as assessed using visual field test (VF), visual evoked potentials (VEP), and electroretinogram (ERG) in PCA patients. Methods: Studies reporting VF, VEPs, and ERG in PCA patients were selected according PRISMA method. Of the 323 articles that emerged from the literature, 17 included the outcomes of interest. To these data, we added those derived from a patient cohort enrolled at our clinic. Results: The literature review included 140 patients, half of them (50%) presented with homonymous hemianopia or quadrantanopia. VEPs were available in 4 patients (2 normal findings, 1 decreased amplitude, and 1 increased latency) and ERG in 3 patients (substantially normal findings). Our case series included 6 patients, presenting with homonymous lateral hemianopia in 50% and contralateral cortical atrophy. VEPs showed normal amplitude in 66-83% according to the stimulation check, and increased latency in 67% in absence of myelin damage on MRI. Latency was increased in both eyes in 50% and only on one side in the other 50%. Such alterations were observed in patients with more severe and symmetric atrophy. ERG showed normal findings. Conclusions: Neurophysiological investigations of the visual pathway in PCA are almost absent in literature. Alterations involve both amplitude and latency and can be also monocular. A multiple-point involvement of the optical pathway can be hypothesized.
Joshua L. Gills, Omonigho Michael Bubu
Obstructive Sleep Apnea and Alzheimer’s Disease Pathology: Is Sleep Architecture the Missing Key?
Abstract: Impairments of the sleep architecture due to disrupted sleep in individuals with obstructive sleep apnea (OSA) may result in reduced slow wave sleep (SWS), intermittent hypoxemia, and excessive day time sleepiness—all factors that have been shown to impact Alzheimer’s disease (AD) risk. In this commentary, we comment on the work by Cavuoto and colleagues in which they examine the associations between nocturnal hypoxemia or sleep disruptions (during SWS) and amyloid-β burden in individuals with OSA. We review the findings in the context of other similar studies and highlight the strengths and weaknesses of these published studies. We note the importance of examining these relationships longitudinally with a large sample size, including considering sleep health disparities, vascular components, and multiple cognitive domain tests.
Neuropsychiatric and Cognitive Symptoms: Two Sides of the Same Coin?
Abstract: Neuropsychiatric symptoms (NPS) are increasingly being recognized as clinical markers for incipient dementia in Alzheimer’s disease (AD dementia). NPS may reinforce cognitive impairment or decline and vice versa. Although NPS are frequent already in mild cognitive impairment, their mechanisms are poorly understood. It is unclear if they share biological mechanisms with cognitive symptoms and how they are associated to structural brain changes, but evidence suggests associations of NPS to cerebral atrophy. An additional NPS dimension in AD dementia concepts might add valuable information to detect patients at risk for AD dementia.
Up Close and Personal with Adult-Onset Leukoencephalopathy
Divya Prabhakaran*, Caroline Grant*, Otto Pedraza, Richard Caselli, Arjun P. Athreya, Melanie Chandler *These authors contributed equally to this work.
Machine Learning Predicts Conversion from Normal Aging to Mild Cognitive Impairment Using Medical History, APOE Genotype, and Neuropsychological Assessment
Abstract: Background: Identifying individuals at risk for mild cognitive impairment (MCI) is of urgent clinical need. Objective: This study aimed to determine whether machine learning approaches could harness longitudinal neuropsychology measures, medical data, and APOE ε4 genotype to identify individuals at risk of MCI 1 to 2 years prior to diagnosis. Methods: Data from 676 individuals who participated in the ‘APOE in the Predisposition to, Protection from and Prevention of Alzheimer's Disease’ longitudinal study (N=66 who converted to MCI) were utilized in supervised machine learning algorithms to predict conversion to MCI. Results: A random forest algorithm predicted conversion 1-2 years prior to diagnosis with 97% accuracy (p=0.0026). The global minima (each individual’s lowest score) of memory measures from the ‘Rey Auditory Verbal Learning Test’ and the ‘Selective Reminding Test’ were the strongest predictors. Conclusions: This study demonstrates the feasibility of using machine learning to identify individuals likely to convert from normal cognition to MCI.
Jingjing Yang, Xizhu Liu, Shahram Oveisgharan, Andrea R. Zammit, Sukriti Nag, David A. Bennett, Aron S. Buchman (Handling Associate Editor: Qu (Teresa) Tian)
Inferring Alzheimer’s Disease Pathologic Traits from Clinical Measures in Living Adults
Abstract: Background: Alzheimer’s disease neuropathologic changes (AD-NC) are important to identify people with high risk for AD dementia (ADD) and subtyping ADD. Objective: Develop imputation models based on clinical measures to infer AD-NC. Methods: We used penalized generalized linear regression to train imputation models for four AD-NC traits (amyloid-β, tangles, global AD pathology, and pathologic AD) in Rush Memory and Aging Project decedents, using clinical measures at the last visit prior to death as predictors. We validated these models by inferring AD-NC traits with clinical measures at the last visit prior to death for independent Religious Orders Study (ROS) decedents. We inferred baseline AD-NC traits for all ROS participants at study entry, and then tested if inferred AD-NC traits at study entry predicted incident ADD and postmortem pathologic AD. Results: Inferred AD-NC traits at the last visit prior to death were related to postmortem measures with R2=(0.188,0.316,0.262) respectively for amyloid-β, tangles, and global AD pathology, and prediction Area Under the receiver operating characteristic Curve (AUC) 0.765 for pathologic AD. Inferred baseline levels of all four AD-NC traits predicted ADD. The strongest prediction was obtained by the inferred baseline probabilities of pathologic AD with AUC=(0.919,0.896) for predicting the development of ADD in 3 and 5 years from baseline. The inferred baseline levels of all four AD-NC traits significantly discriminated pathologic AD profiled eight years later with p-values<1.4×10^(-10). Conclusions: Inferred AD-NC traits based on clinical measures may provide effective AD biomarkers that can estimate the burden of AD-NC traits in aging adults.
Wenlong Su, Hui Li, Hui Dang, Kaiyue Han, Jiajie Liu, Tianhao Liu, Ying Liu, Zhiqing Tang, Haitao Lu, Hao Zhang (Handling Associate Editor: Jianping Jia)
Predictors of Cognitive Functions After Stroke Assessed Using the Wechsler Adult Intelligence Scale: A Retrospective Study
Abstract: Background: The mechanism(s) of cognitive impairment remains complex, making it difficult to confirm the factors influencing post stroke cognitive impairment (PSCI). Objective: This study quantitatively investigated the degree of influence and interactions of clinical indicators of PSCI. Methods: Information from 270 patients with PSCI and their Wechsler Adult Intelligence Scale (WAIS-RC) scores, totaling 18 indicators, were retrospectively collected. Correlations between the indicators and WAIS scores were calculated. Multiple linear regression model (MLR), genetic algorithm modified Back-Propagation neural network (GA-BP), logistic regression model (LR), XGBoost model (XGB), and structural equation model were used to analyze the degree of influence of factors on the WAIS and their mediating effects. Results: Seven indicators were significantly correlated with the WAIS scores: education, lesion side, aphasia, frontal lobe, temporal lobe, diffuse lesions, and disease course. The MLR showed significant effect of education, lesion side, aphasia, diffuse lesions, and frontal lobe on the WAIS. The GA-BP included five factors: education, aphasia, frontal lobe, temporal lobe, and diffuse lesions. LR predicted that the lesion side contributed more to mild cognitive impairment, while education, lesion side, aphasia, and course of the disease contributed more to severe cognitive impairment. XGB showed that education, side of the lesion, aphasia, and diffuse lesions contributed the most to PSCI. Aphasia plays a significant mediating role in patients with severe PSCI. Conclusions: Education, lesion side, aphasia, frontal lobe, and diffuse lesions significantly affected PSCI. Aphasia is a mediating variable between clinical information and the WAIS in patients with severe PSCI.
In Gyoung Ju, Seungmin Lee, Seong Hye Kim, Hyeri Im, Hyeyoon Eo, Myung Sook Oh
Trichosanthis Semen Exerts Neuroprotective Effects in Alzheimer’s Disease Models by Inhibiting Amyloid-β Accumulation and Regulating the Akt and ERK Signaling Pathways
Abstract: Background: Alzheimer’s disease (AD), the most common form of dementia, is characterized by memory loss and the abnormal accumulation of senile plaques composed of amyloid-β (Aβ) protein. Trichosanthis semen (TS) is a traditional herbal medicine used to treat phlegm-related conditions. While TS is recognized for various bioactivities, including anti-neuroinflammatory effects, its ability to attenuate AD remains unknown. Objective: To evaluate the effects of TS extract (TSE) on neuronal damage, Aβ accumulation, and neuroinflammation in AD models. Methods: Thioflavin T and western blot assays were used to assess effects on Aβ aggregation in vitro. TS was treated to PC12 cells with Aβ to assess the neuroprotective effects. Memory functions and histological brain features were investigated in TSE-treated 5×FAD transgenic mice and mice with intracerebroventricularly injected Aβ. Results: TSE disrupted Aβ aggregation and increased the viability of cells and phosphorylation of both protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) in vitro. TSE treatment also suppressed the accumulation of Aβ plaques in the brain of 5×FAD mice, protected neuronal cells in both the subiculum and medial septum, and upregulated Akt/ERK phosphorylation in the hippocampus. Moreover, TSE ameliorated the memory decline and glial overactivation observed in 5×FAD mice. As assessing whether TS affect Aβ-induced neurotoxicity in the Aβ-injected mice, the effects of TS on memory improvement and neuroinflammatory inhibition were confirmed. Conclusions: TSE disrupted Aβ aggregation, protected neurons against Aβ-induced toxicity, and suppressed neuroinflammation, suggesting that it can suppress the development of AD.
Daniele Altomare, Jasmine Rivolta, Ilenia Libri, Irene Mattioli, Valentina Cantoni, Alessandro Padovani, Barbara Borroni
Neuropsychiatric Symptoms in Frontotemporal Dementia: More Than Just Noise?
Abstract: Background: Neuropsychiatric symptoms cause significant suffering and poor quality of life for patients and their caregivers. They are not considered specific to frontotemporal dementia (FTD); therefore, their clinical role and impact might be underestimated. Objective: The aims of the present study are to: 1) describe the prevalence of neuropsychiatric symptoms in FTD starting from the prodromal stage, 2) define their association with disease severity, 3) identify symptoms which are unrelated to FTD-specific symptoms, and 4) assess their association with clinical features and outcomes. Methods: In this retrospective study, we analyzed data of 461 FTD patients, including behavioral variant of FTD (bvFTD, n=318) and primary progressive aphasia (PPA, n=143). Neuropsychiatric symptoms were assessed using the Neuropsychiatric Inventory, and patients’ staging and global disease severity were estimated using the Clinical Dementia Rating plus NACC FTLD. Results: The most common neuropsychiatric symptoms in prodromal FTD were irritability (48%), depression (35%), and anxiety (34%); delusions were reported in 6% of prodromal bvFTD cases. The severity of most neuropsychiatric symptoms increased with global disease severity. Psychosis (delusions and hallucinations) and mood symptoms (depression and anxiety) were mostly independent from FTD-specific symptoms. Psychosis was associated with older age, higher disease severity, shorter survival rate, and was higher in bvFTD than in PPA. Conclusions: Neuropsychiatric symptoms are common in patients with FTD, also in the prodromal phase. Psychosis might be unrelated to FTD pathology, and be associated with worse clinical outcomes. The prompt detection and treatment of these symptoms might improve patient’s management and quality of life.
Salvatore Putignano, Luigi Forgione, Mariano Fusco, Attilio Giacummo, Elisa Magli, Saverio Marino, Raffaele Marzano, Daria Putignano, Francesco Santamaria, Micaela Spatarella, Vincenzo Santagada
Early Detection Screening of Cognitive Decline in Patients Over 60 Years: ELDERCARE Study
Abstract Background: Dementia is the fourth leading cause of death in people >65 years old in western countries. Objective: This cross-sectional assisted survey aimed to evaluate a multidisciplinary team approach of specialists of the Associazione Geriatri Extraospedalieri a favore di Anziani Svantaggiati and pharmacists to facilitate progress in the early identification and management of cognitive decline in patients >60 years. Methods: A multidisciplinary team conducted this cross-sectional assisted survey. Patients (>60 years) with independent and/or assisted walking, subjective memory impairment, mild cognitive impairment or mild Alzheimer’s disease (AD) who regularly attended pharmacies underwent the survey. An internal medical examination, a cardiovascular visit, and a short neuropsychological evaluation were conducted for each patient. Demographic, anamnestic, and clinical data were collected anonymously. Results: 279 eligible patients underwent the screening phase. 44% were overweight, 23% obese and 29% hypertensive. 62% of cases showed alterations of supra-aortic trunk with different percentages of stenosis. The neuropsychological evaluation highlighted that 67% of cases were normal according to age and education level, while 18% were in a state condition of cognitive frailty. Mild/moderate cognitive decline, or probably AD, was identified in 14% of cases. Conclusions: A multidisciplinary collaboration between pharmacists and specialist medical doctors is essential in early identification of prodromal symptoms of cognitive impairment and AD. The Prompt detection of the condition in this group of patients allowed the specialists to recommend in-depth diagnostic tests and follow-up procedures to slow the course of the disease. This would give time to carry out adequate caregiver training.
Stanisław J. Czuczwar, Janusz Kocki, Barbara Miziak, Jacek Bogucki, Anna Bogucka-Kocka, Ryszard Pluta
Alpha-, Beta-, and Gamma-Secretase, Amyloid Precursor Protein, and Tau Protein Genes in the Hippocampal CA3 Subfield in an Ischemic Model of Alzheimer’s Disease with Survival up to 2 Years
Abstract: Background: Understanding the phenomena underlying the non-selective susceptibility to ischemia of pyramidal neurons in the CA3 is important from the point of view of elucidating the mechanisms of memory loss and the development dementia. Objective: The aim of the study was to investigate changes in genes expression of amyloid precursor protein, its cleaving enzymes and tau protein in CA3 post-ischemia with survival of 12-24 months. Methods: We used an ischemic model of Alzheimer's disease to study the above genes using an RT-PCR protocol. Results: The expression of the amyloid precursor protein gene was above the control values at all times post-ischemia. The expression of the α-secretase gene also exceeded the control values post-ischemia. The expression of the β-secretase gene increased 12 and 24 months post-ischemia, and 18 months was below control values. Presenilin 1 and 2 genes expression was significantly elevated at all times post-ischemia. Also, tau protein gene expression was significantly elevated throughout the observation period, and peak gene expression was present 12 months post-ischemia. Conclusions: The study suggests that the genes studied are involved in the non-amyloidogenic processing of amyloid precursor protein. Additionally data indicate that brain ischemia with long-term survival causes damage and death of pyramidal neurons in the CA3 area of the hippocampus in a modified tau protein-dependent manner. Thus defining a new and important mechanism of pyramidal neuronal death in the CA3 area post-ischemia. In addition expression of tau protein gene modification after brain ischemia is useful in identifying ischemic mechanisms occurring in Alzheimer's disease.
Nimish K. Acharya*, Henya C. Grossman*, Peter M. Clifford, Eli C. Levin, Kenneth R. Light, Hana Choi, Randel L. Swanson II, Mary C. Kosciuk, Venkat Venkataraman, David J. Libon, Louis D. Matzel, Robert G. Nagele (Handling Associate Editor: David Loewenstein) *These authors contributed equally to this work.
A Chronic Increase in Blood-Brain Barrier Permeability Facilitates Intraneuronal Deposition of Exogenous Bloodborne Amyloid-Beta1-42 Peptide in the Brain and Leads to Alzheimer’s Disease-Relevant Cognitive Changes in a Mouse Model
Abstract: Background: Increased blood-brain barrier (BBB) permeability and amyloid-β (Aβ) peptides (especially Aβ1-42) (Aβ42) have been linked to Alzheimer’s disease (AD) pathogenesis, but the nature of their involvement in AD-related neuropathological changes leading to cognitive changes remains poorly understood. Objective: To test the hypothesis that chronic extravasation of bloodborne Aβ42 peptide and brain-reactive autoantibodies and their entry into the brain parenchyma via a permeable BBB contribute to AD-related pathological changes and cognitive changes in a mouse model. Methods: The BBB was rendered chronically permeable through repeated injections of Pertussis toxin (PT), and soluble monomeric, fluorescein isothiocyanate (FITC)-labeled or unlabeled Aβ42 was injected into the tail-vein of 10-month-old male CD1 mice at designated intervals spanning ~3 months. Acquisition of learned behaviors and long-term retention were assessed via a battery of cognitive and behavioral tests and linked to neuropathological changes. Results: Mice injected with both PT and Aβ42 demonstrated a preferential deficit in the capacity for long-term retention and an increased susceptibility to interference in selective attention compared to mice exposed to PT or saline only. Immunohistochemical analyses revealed increased BBB permeability and entry of bloodborne Aβ42 and immunoglobulin G (IgG) into the brain parenchyma, selective neuronal binding of IgG and neuronal accumulation of Aβ42 in animals injected with both PT and Aβ42 compared to controls. Conclusions: Results highlight the potential synergistic role of BBB compromise and the influx of bloodborne Aβ42 into the brain in both the initiation and progression of neuropathologic and cognitive changes associated with AD.
Neil Vaishnav, Rosa Gonzalez, Krystal Karunungan, Ana Tyler, William Zheng, Jalayne J. Arias
Creating an Unprotected Class: Addressing Legal Risks in the Era of Biologically-Defined Alzheimer’s Disease
Abstract: Background: Documentation of preclinical biomarker tests for Alzheimer’s disease (AD) in the medical record may expose patients to employment and insurance discrimination risks. There is a gap in research describing clinicians’ approaches to documenting biomarker results. Objective: To evaluate discrimination risks faced by patients undergoing biomarker testing for AD through a qualitative analysis of clinician documentation practices. Methods: Semi-structured interviews using hypothetical patient scenarios. The qualitative analysis focused on interviewees’ responses related to documentation and disclosure of results. Results: We collected and analyzed 17 interviews with dementia experts; and identified three approaches to documenting biomarkers as: an association with active AD, noninformative, and an increased susceptibility for AD. Those who associated biomarkers with active disease were more likely to favor disclosure to employers and insurers, which could increase discrimination risks. Conclusions: This study demonstrates the variety of documentation and disclosure practices likely to emerge for preclinical AD biomarker tests and highlights a need for guidelines in this area.
Sung-a Kim, Megumi Maeda, Fumiko Murata, Takayuki Fujii, Emi Ueda, Rei Ono, Haruhisa Fukuda
Impact of Concurrent Visual and Hearing Impairment on Incident Alzheimer’s Disease: The LIFE Study
Abstract: Background: The prevalence of Alzheimer's disease (AD) is increasing in Japan due to population aging. The association between sensory impairment and incident AD remains unclear. Objective: This study aimed to investigate the impact of sensory impairment on incident AD. Methods: We analyzed residents of five municipalities participating in the Longevity Improvement & Fair Evidence (LIFE) Study. The participants comprised individuals who had newly applied for long-term care needs certification between 2017 and 2022 and had no cognitive impairment upon application or AD diagnosis within the preceding six months. Participants were classified according to sensory impairment status: visual impairment (VI), hearing impairment (HI), neither sensory impairment (NSI), and dual sensory impairment (DSI). The month succeeding the certification application was set as the index month, and the interval from that month until AD onset was assessed. Multivariable Cox proportional hazards analysis was performed to calculate the risk of AD onset according to sensory impairment status while adjusting for sex, age, dependence level, self-reliance level, and comorbidities. Results: Among 14,186 participants, we identified 1,194 (8.4%) who developed AD over a median follow-up period of 22.6 months. VI and HI only were not associated with incident AD. However, DSI conferred a significantly higher risk (HR: 1.6, CI: 1.1-2.2, p=0.008) of AD onset than NSI. Conclusions: Individuals with concurrent DSI have a higher risk of developing AD than those with single or NSI. Preventing and treating sensory impairment may not only improve functional outcomes, but could also help to reduce the future risk of AD.
Haoqi Sun*, Peng Li*, Lei Gao, Jingyun Yang, Lei Yu, Aron S. Buchman, David A. Bennett, M. Brandon Westover, Kun Hu (Handling Associate Editor: Sheng Luo) *These authors contributed equally to this work.
Altered Motor Activity Patterns within 10-Minute Timescale Predict Incident Clinical Alzheimer’s Disease
Abstract: Background: Fractal motor activity regulation (FMAR), characterized by self-similar temporal patterns in motor activity across timescales, is robust in healthy young humans but degrades with aging and in Alzheimer’s disease (AD). Objective: To determine the timescales where alterations of FMAR can best predict the clinical onset of AD. Methods: FMAR was assessed from actigraphy at baseline in 1,077 participants who had annual follow-up clinical assessments for up to 15 years. Survival analysis combined with deep learning (DeepSurv) was used to examine how baseline FMAR at different timescales from 3 minutes up to 6 hours contributed differently to the risk for incident clinical AD. Results: Clinical AD occurred in 270 participants during the follow-up. DeepSurv identified three potential regions of timescales in which FMAR alterations were significantly linked to the risk for clinical AD: <10, 20-40, and 100-200 minutes. Confirmed by the Cox and random survival forest models, the effect of FMAR alterations in the timescale of <10 minutes was the strongest, after adjusting for covariates. Conclusions: Subtle changes in motor activity fluctuations predicted the clinical onset of AD, with the strongest association observed in activity fluctuations at timescales <10 minutes. These findings suggest that short actigraphy recordings may be used to assess the risk of AD.
Farid Rajabli, Azizi A. Seixas, Bilcag Akgun, Larry D. Adams, Jovita Inciute, Kara L. Hamilton, Patrice G. Whithead, Ioanna Konidari, Tianjie Gu, Jamie Arvizu, Charles G. Golightly, Takiyah D. Starks, Renee Laux, Goldie S. Byrd, Jonathan L. Haines, Gary W. Beecham, Anthony J. Griswold, Jeffery M. Vance, Michael L. Cuccaro, Margaret A. Pericak-Vance
African Ancestry Individuals with Higher Educational Attainment Are Resilient to Alzheimer’s Disease Measured by pTau181
Abstract: Background: Cognitive and functional abilities in individuals with Alzheimer’s disease (AD) pathology (ADP) are highly variable. Factors contributing to this variability are not well understood. Previous research indicates that higher educational attainment (EA) correlates with reduced cognitive impairments among those with ADP. While cognitive and functional impairments are correlated, they are distinguishable in their manifestations. Objective: To investigate whether levels of education are associated with functional impairments among those with ADP. Methods: This research involved 410 African American (AA) individuals (Institutional Review Boards 20070307, 01/27/2023) to ascertain whether EA correlates with functional resilience and if this effect varies between APOE ε4 carriers and non-carriers. Utilizing EA as a cognitive reserve proxy, CDR-FUNC as a functional difficulties measure, and blood pTau181 as an ADP proxy, the non-parametric Mann-Whitney U test assessed the relationship between EA and CDR-FUNC in individuals with advanced pTau181 levels. Results: The results showed that EA correlated with functional difficulties in AA individuals with high levels of pTau181, such that individuals with high EA are more likely to have better functional ability compared to those with lower EA (W=730.5, p=0.0007). Additionally, we found that the effect of high EA on functional resilience was stronger in ε4 non-carriers compared to ε4 carriers (W=555.5, p=0.022). Conclusions: This study extends the role of cognitive reserve and EA to functional performance showing that cognitive reserve influences the association between ADP burden and functional difficulties. Interestingly, this protective effect seems less pronounced in carriers of the strong genetic risk allele ε4.
Bhargav T. Nallapu, Kellen K. Petersen, Richard B. Lipton, Christos Davatzikos, Ali Ezzati, for the Alzheimer’s Disease Neuroimaging Initiative
Plasma Biomarkers as Predictors of Progression to Dementia in Individuals with Mild Cognitive Impairment
Abstract: Background: Blood-based biomarkers (BBMs) are of growing interest in the field of Alzheimer's disease (AD) and related dementias. Objective: This study aimed to assess the ability of plasma biomarkers to 1) predict disease progression from mild cognitive impairment (MCI) to dementia and 2) improve the predictive ability of magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) measures when combined. Methods: We used data from the Alzheimer's Disease Neuroimaging Initiative. Machine learning models were trained using the data from participants who remained cognitively stable (CN-s) and with Dementia diagnosis at 2-year follow-up visit. The models were used to predict progression to dementia in MCI individuals. We assessed the performance of models with plasma biomarkers against those with CSF and MRI measures, and also in combination with them. Results: Our models with plasma biomarkers classified CN-s individuals from AD with an AUC of 0.75±0.03 and could predict conversion to dementia in MCI individuals with an AUC of 0.64±0.03 (17.1% BP, base prevalence). Models with plasma biomarkers performed better when combined with CSF and MRI measures (CN versus AD: AUC of 0.89±0.02; MCI-to-AD: AUC of 0.76±0.03, 21.5% BP). Conclusions: Our results highlight the potential of plasma biomarkers in predicting conversion to dementia in MCI individuals. While plasma biomarkers could improve the predictive ability of CSF and MRI measures when combined, they also show the potential to predict non-progression to AD when considered alone. The predictive ability of plasma biomarkers is crucially linked to reducing the costly and effortful collection of CSF and MRI measures.
Mohammad Golam Sabbir
Cholinergic Receptor Muscarinic 1 Co-Localized with Mitochondria in Cultured Dorsal Root Ganglion Neurons, and Its Deletion Disrupted Mitochondrial Ultrastructure in Peripheral Neurons: Implications in Alzheimer’s Disease
Background: Loss of Cholinergic Receptor Muscarinic 1 (CHRM1) has been linked to the pathogenesis of Alzheimer's disease (AD). Our recent study found significantly lower CHRM1 protein levels in AD patient cortices, linked to reduced survival. Furthermore, using knockout mice (Chrm1-/-) we demonstrated that deletion of Chrm1 alters cortical mitochondrial structure and function, directly establishing a connection between its loss and mitochondrial dysfunction in the context of AD. While CHRM1's role in the brain has been extensively investigated, its impact on peripheral neurons in AD remains a crucial area of research, especially considering reported declines in peripheral nerve conduction among AD patients. Objective: The objective was to characterize Chrm1 localization and mitochondrial deficits in Chrm1-/- dorsal root ganglion (DRG) neurons. Methods: Recombinant proteins tagged with Green or Red Fluorescent Protein (GFP/RFP) were transiently expressed to investigate the localization of Chrm1 and mitochondria, as well as mitochondrial movement in the neurites of cultured primary mouse DRG neurons, using confocal time-lapse live cell imaging. Transmission electron microscopy was performed to examine the ultrastructure of mitochondria in both wild-type and Chrm1-/- DRGs. Results: Fluorescence imaging revealed colocalization and comigration of N-terminal GFP-tagged Chrm1 and mitochondrial localization signal peptide-tagged RFP-labelled mitochondria in the DRGs neurons. A spectrum of mitochondrial structural abnormalities, including disruption and loss of cristae was observed in 87% neurons in Chrm1-/- DRGs. Conclusions: This study suggests that Chrm1 may be localized in the neuronal mitochondria and loss of Chrm1 in peripheral neurons causes sever mitochondrial structural aberrations resembling AD pathology.
Gus Alva, Wiesław J. Cubała, Ana Berrio, Bruce Coate, Victor Abler, Sanjeev Pathak
Safety Profile of Pimavanserin Therapy in Elderly Patients with Neurodegenerative Disease-Related Neuropsychiatric Symptoms: A Phase 3B Study
Abstract: Background: Pimavanserin, a 5-HT2A receptor inverse agonist/antagonist, is the only medication approved by the FDA for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis (PDP). Further expanding knowledge of the safety profile of pimavanserin in PDP and neurodegenerative diseases (NDD) such as Alzheimer’s disease is of great interest for informing its use in patients with PDP (with or without dementia), given this population is highly sensitive to adverse effects following antipsychotic use. Objective: This trial evaluated the effects of pimavanserin compared to placebo in frail older adults and elderly patients with neuropsychiatric symptoms related to NDD, such as hallucinations and delusions, to better understand the safety of pimavanserin in this population. Methods: This was a phase 3b, 8-week treatment (study duration of up to 16 weeks), multicenter, randomized, double-blind, placebo-controlled, two-arm parallel-group trial (NCT03575052). The primary endpoint was safety and tolerability, measured by treatment-emergent adverse events (TEAEs). Secondary safety endpoints were change from baseline in motor and cognitive function; exploratory endpoints included suicidality, sleep quality, and neuropsychiatric symptoms. Results: Incidence of TEAEs were similar between treatment groups; 29.8% reported ≥1 TEAE (pimavanserin: 30.4%; placebo: 29.3%) and 1.8% reported serious TEAEs (pimavanserin: 2.0%; placebo: 1.5%). Pimavanserin did not impact motor- or cognitive-related function. Conclusions: Pimavanserin was well-tolerated and not associated with motor or cognitive impairment. Together these findings highlight the manageable and generally favorable safety profile of pimavanserin in patients with NDD, contributing to our knowledge on the safety of pimavanserin as it generalizes to patients with PDP.
Kosuke Matsuzono, Takafumi Mashiko, Reiji Koide, Hiroaki Yoshizumi, Shigeru Fujimoto
Comparison of Prognosis and Cognitive Function of Holistic Neurological Disease: Tochigi Neurological Disease Cohort Study
Abstract: Background: While many studies focus on the prognosis of individual neurological diseases, very few comprehensively compare and analyze real-world data of these diseases. Objective: To address this gap in knowledge, in this study, we comprehensively analyzed the real-life data of patients with neurological diseases. Methods: We prospectively enrolled patients with neurological diseases at three hospitals from December 1, 2016 to September 30, 2020. Neurological diseases were classified into nine groups: Dementia, Cerebrovascular disease, Parkinson’s and related, Functional, Spinocerebellar degeneration, Neuroimmune, Epilepsy, Muscle dystrophy disease, and Hypertension. Patients were followed up for three years, and their prognosis and evaluation of their cognitive function served as the endpoint. Results: A total of 426 patients were finally enrolled. Both mortality and cognitive function differed among the neurological disease categories. After 3 years, mortality was highest in the Dementia (25.5%), Parkinson’s and related (21.6%), and Spinocerebellar degeneration (35.3%) groups while the cognitive function of patients in these three groups was significantly lowest. Conclusions: When the neurological diseases were holistically observed, both mortality and cognitive function of the Dementia, Parkinson’s and related, and Spinocerebellar degeneration groups were significantly worse than the remaining diseases.
Ivonne Torres-Atencio*, Maria B. Carreira*, Alondra Méndez, Maryonelly Quintero, Adriana Broce, Diana C. Oviedo, Giselle Rangel, Alcibiades E. Villarreal, Adam E. Tratner, Sofía Rodríguez-Araña, Gabrielle B. Britton for the Panama Aging Research Initiative-Health Disparities (PARI-HD) Study (Handling Associate Editor: Emily Reeve) *These authors contributed equally to this work.
Polypharmacy and Associated Health Outcomes in the PARI-HD Study
Abstract: Background: A growing body of evidence points to potential risks associated with polypharmacy (using ≥5 medications) in older adults, but most evidence is derived from studies where racial and ethnic minorities remain underrepresented among research participants. Objective: Investigate the association between polypharmacy and cognitive function, subjective health state, frailty, and falls in Hispanic older adults. Methods: Panama Aging Research Initiative–Health Disparities (PARI-HD) is a community-based cohort study of older adults free of dementia at baseline. Cognitive function was measured with a neuropsychological test battery. Frailty assessment was based on the Fried criteria. Subjective health state and falls were self-reported. Linear and multinomial logistic regression analyses were used to examine association. Results: Baseline evaluations of 468 individuals with a mean age of 69.9 years (SD = 6.8) were included. The median number of medications was 2 (IQR: 1–4); the rate of polypharmacy was 19.7% (95% confidence interval [CI] = 16.1-23.3). Polypharmacy was inversely associated with self-rated overall health (b = -5.89, p < 0.01). Polypharmacy users had 2.3 times higher odds of reporting two or more falls in the previous 12 months (odds ratio [OR] = 2.31, 95% CI = 1.06-5.04). Polypharmacy was independently associated with Fried’s criteria for pre-frailty (OR = 2.90, 95% CI = 1.36-5.96) and frailty (OR = 5.14, 95% CI = 1.83-14.42). Polypharmacy was not associated with cognitive impairment. Conclusions: These findings illustrate the potential risks associated with polypharmacy among older adults in Panama and may inform interventions to improve health outcomes in this population.
Robert A. Culibrk, Katherine A. Ebbert, Daniel J. Yeisley, Rui Chen, Fatir A. Qureshi, Juergen Hahn, Mariah S. Hahn
Impact of Suramin on Key Pathological Features of Sporadic Alzheimer’s Disease-Derived Forebrain Neurons
Abstract: Background: Alzheimer’s disease (AD) is characterized by disrupted proteostasis and macroautophagy (hereafter “autophagy”). The pharmacological agent suramin has known autophagy modulation properties with potential efficacy in mitigating AD neuronal pathology. Objective: In the present work, we investigate the impact of forebrain neuron exposure to suramin on the Akt/mTOR signaling pathway, a major regulator of autophagy, in comparison with rapamycin and chloroquine. We further investigate the effect of suramin on several AD-related biomarkers in sporadic AD (sAD)-derived forebrain neurons. Methods: Neurons differentiated from ReNcell neural progenitors were used to assess the impact of suramin on the Akt/mTOR signaling pathway relative to the autophagy inducer rapamycin and autophagy inhibitor chloroquine. Mature forebrain neurons were differentiated from induced pluripotent stem cells (iPSCs) sourced from a late-onset sAD patient and treated with 100 µM suramin for 72 h, followed by assessments for amyloid-β, phosphorylated tau, oxidative/nitrosative stress, and synaptic puncta density. Results: Suramin treatment of sAD-derived neurons partially ameliorated the increased p-Tau(S199)/Tau ratio, and fully remediated the increased glutathione to oxidized nitric oxide ratio, observed in untreated sAD-derived neurons relative to healthy controls. These positive results may be due in part to the distinct increases in Akt/mTOR pathway mediator p-p70S6K noted with suramin treatment of both ReNcell-derived and iPSC-derived neurons. Longer term neuronal markers, such as synaptic puncta density, were unaffected by suramin treatment. Conclusions: These findings provide initial evidence supporting the potential of suramin to reduce the degree of dysregulation in sAD-derived forebrain neurons in part via the modulation of autophagy.
Caroline O. Nester, Qi Gao, Mindy J. Katz, Jacqueline A. Mogle, Cuiling Wang, Carol A. Derby, Richard B. Lipton, Andrew J. Saykin, Laura A. Rabin
Does the Cognitive Change Index Predict Future Cognitive and Clinical Decline? Longitudinal Analysis in a Demographically Diverse Cohort
Abstract: Background: The Cognitive Change Index (CCI) is a widely-used measure of self-perceived cognitive ability and change. Unfortunately, it is unclear if the CCI predicts future cognitive and clinical decline. Objective: We evaluated baseline CCI to predict transition from normal cognition to cognitive impairment in nondemented older adults and in predementia groups including, subjective cognitive decline, motoric cognitive risk syndrome, and mild cognitive impairment. Different versions of the CCI were assessed to uncover any differential risk sensitivity. We also examined the effect of ethnicity/race on CCI. Methods: Einstein Aging Study participants (N=322, Mage=77.57±4.96, %female=67.1, Meducation=15.06±3.54, %non-Hispanic white=46.3) completed an expanded 40-item CCI version (CCI-40) and neuropsychological evaluation (including Clinical Dementia Rating Scale [CDR], Montreal Cognitive Assessment, and Craft Story) at baseline and annual follow-up (Mfollow-up=3.4 years). CCI-40 includes the original 20 items (CCI-20) and the first 12 memory items (CCI-12). Linear mixed effects models (LME) and generalized LME assessed the association of CCI total scores at baseline with rate of decline in neuropsychological tests and CDR. Results: In the overall sample and across predementia groups, the CCI was associated with rate of change in log odds on CDR, with higher CCI at baseline predicting faster increase in the odds of being impaired on CDR. The predictive validity of the CCI broadly held across versions (CCI-12, 20, 40) and ethnic/racial groups (non-Hispanic black and white). Conclusions: Self-perception of cognitive change on the CCI is a useful marker of dementia risk in demographically/clinically diverse nondemented samples. All CCI versions successfully predicted decline.
Patricia Cogram, B. Maximiliano Garduño, Bing Ren, Xiangmin Xu
First International Conference on Unconventional Animal Models of Alzheimer’s Disease and Aging
Abstract: The first International Conference on Unconventional Animal Models of Alzheimer’s Disease and Aging (UAMAA) took place on December 13–16, 2023, in Santiago, Chile. The Alzheimer’s disease (AD) research field currently search for new and unconventional models that could hold greater translational potential than transgenic mouse models. Thus this UAMAA conference is timely and significant. The event consisted of 6 sessions with talks from 28 world-class scientists from all over the world. These animal models of interest include the degu (Octodon degu), the dog (Canis familiaris), and certain species of nonhuman primates that may better recapitulate neuropathology and cognitive impairments in human AD. Our conference has provided a formal forum to discuss and highlight new research directions, alternative animal models, and innovative approaches for the AD and aging research field.
Living Up to the Promise of Preventing Dementia. A review of Dementia Does Not Start in the Brain: A New Paradigm in the Prevention of Cognitive Decline: Prevention is the New Cure by Patrick Scott Smith, 2023, 224 pp. ISBN 9781916787858. Reviewed by George Perry, PhD