Dementia clinical trial implications of mild behavioral impairment

Tau-PET in early cortical Alzheimer brain regions in relation to mild behavioral impairment in older adults with either normal cognition or mild cognitive impairment

Mild Behavioral Impairment (MBI) leverages later-life emergent and persistent neuropsychiatric symptoms (NPS) to identify a high-risk group for incident dementia. Phosphorylated tau (p-tau) is a hallmark biological manifestation of Alzheimer disease (AD). We investigated associations between MBI and tau accumulation in early-stage AD cortical regions. In 442 Alzheimer's Disease Neuroimaging Initiative participants with normal cognition or mild cognitive impairment, MBI status was determined alongside corresponding p-tau and Aβ. Two meta-regions of interest were generated to represent Braak I and III neuropathological stages. Multivariable linear regression modelled the association between MBI as independent variable and tau tracer uptake as dependent variable. Among Aβ positive individuals, MBI was associated with tau uptake in Braak I (β=0.45(0.15), p<.01) and Braak III (β=0.24(0.07), p<.01) regions. In Aβ negative individuals, MBI was not associated with tau in the Braak I region (p=0.11) with a negative association in Braak III (p=.01). These findings suggest MBI may be a sequela of neurodegeneration, and can be implemented as a cost-effective framework to help improve screening efficiency for AD.

Tau-PET in early cortical Alzheimer brain regions in relation to mild behavioral impairment in older adults with either normal cognition or mild cognitive impairment

Mild Behavioral Impairment (MBI) leverages later-life emergent and persistent neuropsychiatric symptoms (NPS) to identify a high-risk group for incident dementia. Phosphorylated tau (p-tau) is a hallmark biological manifestation of Alzheimer disease (AD). We investigated associations between MBI and tau accumulation in early-stage AD cortical regions. In 442 Alzheimer's Disease Neuroimaging Initiative participants with normal cognition or mild cognitive impairment, MBI status was determined alongside corresponding p-tau and Aβ. Two meta-regions of interest were generated to represent Braak I and III neuropathological stages. Multivariable linear regression modelled the association between MBI as independent variable and tau tracer uptake as dependent variable. Among Aβ positive individuals, MBI was associated with tau uptake in Braak I (β =0.45(0.15), p<.01) and Braak III (β =0.24(0.07), p<.01) regions. In Aβ negative individuals, MBI was not associated with tau in the Braak I region (p=.11) with a negative association in Braak III (p=.01). These findings suggest MBI may be a sequela of neurodegeneration, and can be implemented as a cost-effective framework to help improve screening efficiency for AD.

Neuropsychiatric Manifestations in Alzheimer's Disease Patients: Genetics and Treatment Options

BACKGROUND

Alzheimer's disease (AD) is characterized by neuropsychiatric symptoms (NPS), which cause great misery to those with dementia and those who care for them and may lead to early institutionalization.

OBJECTIVE

The present systematic review aims to discuss the various aspects of Alzheimer's, including treatment options.

METHODS

The databases Embase, PubMed, and Web of Science were searched to collect data.

RESULTS

Incipient cognitive deterioration is commonly accompanied by these early warning signals of neurocognitive diseases. The neurobiology of NPSs in Alzheimer's disease, as well as particular symptoms, including psychosis, agitation, apathy, sadness, and sleep disorders, will be examined in this review. For NPSs in Alzheimer's disease, clinical trial designs, as well as regulatory issues, were also addressed. A fresh wave of research, however, is helping to push the discipline ahead. For medication development and repurposing, we highlight the most recent results in genetics, neuroimaging, and neurobiology. Even though identifying and treating psychosis in adults with dementia is still a challenging endeavor, new options are coming up that give the field fresh focus and hope. Conclsuion: It can be concluded from the complete literature survey that Alzheimer's-related psychosis as well as other symptoms that are not psychotic, have made significant progress in the last decade. These milestones in the development of safer, more effective treatments have been achieved as a consequence of great focus on non-pharmacological interventions like DICE or WHELD; the investigation into ways to improve existing drugs like aripiprazole, risperidone, amisulpride, and Escitalopram for safer precision-based treatment; and the development of a clinical trial program for pimavanserin.

Cognitive profile of people with mild behavioral impairment in Brain Health Registry participants

OBJECTIVES

Dementia assessment includes cognitive and behavioral testing with informant verification. Conventional testing is resource-intensive, with uneven access. Online unsupervised assessments could reduce barriers to risk assessment. The aim of this study was to assess the relationship between informant-rated behavioral changes and participant-completed neuropsychological test performance in older adults, both measured remotely via an online unsupervised platform, the Brain Health Registry (BHR).

DESIGN

Observational cohort study.

SETTING

Community-dwelling older adults participating in the online BHR. Informant reports were obtained using the BHR Study Partner Portal.

PARTICIPANTS

The final sample included 499 participant-informant dyads.

MEASUREMENTS

Participants completed online unsupervised neuropsychological assessment including Forward Memory Span, Reverse Memory Span, Trail Making B, and Go/No-Go tests. Informants completed the Mild Behavioral Impairment Checklist (MBI-C) via the BHR Study Partner portal. Cognitive performance was evaluated in MBI+/- individuals, as was the association between cognitive scores and MBI symptom severity.

RESULTS

Mean age of the 499 participants was 67, of which 308/499 were females (61%). MBI + status was associated with significantly lower memory and executive function test scores, measured using Forward and Reverse Memory Span, Trail Making Errors and Trail Making Speed. Further, significant associations were found between poorer objectively measured cognitive performance, in the domains of memory and executive function, and MBI symptom severity.

CONCLUSION

These findings support the feasibility of remote, informant-reported behavioral assessment utilizing the MBI-C, supporting its validity by demonstrating a relationship to online unsupervised neuropsychological test performance, using a previously validated platform capable of assessing early dementia risk markers.

Persistence of neuropsychiatric symptoms and dementia prognostication: A comparison of three operational case definitions of mild behavioral impairment

INTRODUCTION

We compared three operational case definitions of mild behavioral impairment (MBI) in the context of MBI prevalence estimates and dementia risk modeling.

METHODS

Participants were dementia-free older adults (n = 13701) from the National Alzheimer's Coordinating Center. Operational case definitions of MBI were generated based on neuropsychiatric symptoms at one (OV), two-consecutive (TCV), or more than two-thirds (TTV) of dementia-free study visits. Definitions were compared in prevalence and in Cox regressions using MBI to predict incident dementia.

RESULTS

OV MBI was the most prevalent (54.4%), followed by TCV (32.3%) and TTV (26.7%) MBI. However, OV MBI had the lowest rate of incident dementia (hazard ratio [HR] = 2.54, 95% confidence interval [CI]: 2.33-2.78) and generated poorer model metrics than TCV MBI (HR = 4.06, 95% CI: 3.74-4.40) and TTV MBI (HR = 5.77, 95% CI: 5.32-6.26).

DISCUSSION

Case ascertainment with longer timeframe MBI operational case definitions may more accurately define groups at risk of dementia in datasets lacking tools designed to detect MBI.Highlights: Mild behavioral impairment (MBI) can identify older adults at risk of dementia.Neuropsychiatric symptom (NPS) assessment tools can be proxy measures for MBI.Hazard for dementia was highest for MBI defined by NPS presence at more than two-thirds of visits.

Effects of race, baseline cognition, and APOE on the association of affective dysregulation with incident dementia: A longitudinal study of dementia-free older adults

BACKGROUND

Affective symptoms are dementia risk factors. Mild behavioral impairment (MBI) is a neurobehavioral syndrome that refines incorporation of psychiatric symptomatology into dementia prognostication by stipulating symptoms must emerge de novo in later life and persist for ≥6 months. Here, we investigated the longitudinal association of MBI-affective dysregulation with incident dementia.

METHODS

National Alzheimer Coordinating Centre participants with normal cognition (NC) or mild cognitive impairment (MCI) were included. MBI-affective dysregulation was operationalized as Neuropsychiatric Inventory Questionnaire-measured depression, anxiety, and elation at two consecutive visits. Comparators had no neuropsychiatric symptoms (no NPS) in advance of dementia. Cox proportional hazard models were implemented to assess the risk of dementia, adjusted for age, sex, years of education, race, cognitive diagnosis, and APOE-ε4 status, with interaction terms as appropriate.

RESULTS

The final sample included 3698 no-NPS (age:72.8; 62.7 % female), and 1286 MBI-affective dysregulation participants (age:75; 54.5 % female). MBI-affective dysregulation had lower dementia-free survival (p < 0.0001) and greater incidence of dementia (HR = 1.76, CI:1.48-2.08, p < 0.001) versus no NPS. Interaction analyses revealed that MBI-affective dysregulation was associated with higher dementia incidence in Black participants than White (HR = 1.70, CI:1.00-2.87, p = 0.046), NC than MCI (HR = 1.73, CI:1.21-2.48, p = 0.0028), and APOE-ε4 noncarriers than carriers (HR = 1.47, CI:1.06-2.02, p = 0.0195). Of MBI-affective dysregulation converters to dementia, 85.5 % developed Alzheimer's disease, which increased to 91.4 % in those with amnestic MCI.

LIMITATIONS

MBI-affective dysregulation was not stratified by symptom to further examine dementia risk.

CONCLUSIONS

Emergent and persistent affective dysregulation in dementia-free older adults is associated with substantial risk for dementia and should be considered in clinical assessments.

Therapeutic potential of natural molecules against Alzheimer's disease via SIRT1 modulation

Alzheimer's disease (AD) is a neurodegenerative disease mainly characterized by progressive cognitive dysfunction and memory impairment. Recent studies have shown that regulating silent information regulator 1 (SIRT1) expression has a significant neuroprotective effect, and SIRT1 may become a new therapeutic target for AD. Natural molecules are an important source of drug development for use in AD therapy and may regulate a wide range of biological events by regulating SIRT1 as well as other SIRT1-mediated signaling pathways. This review aims to summarize the correlation between SIRT1 and AD and to identify in vivo and in vitro studies investigating the anti-AD properties of natural molecules as modulators of SIRT1 and SIRT1-mediated signaling pathways. A literature search was conducted for studies published between January 2000 and October 2022 using various literature databases, including Web of Science, PubMed, Google Scholar, Science Direct, and EMBASE. Natural molecules, such as resveratrol, quercetin, icariin, bisdemethoxycurcumin, dihydromyricetin, salidroside, patchouli, sesamin, rhein, ligustilide, tetramethoxyflavanone, 1-theanine, schisandrin, curcumin, betaine, pterostilbene, ampelopsin, schisanhenol, and eriodictyol, have the potential to modulate SIRT1 and SIRT1 signaling pathways, thereby combating AD. The natural molecules modulating SIRT1 discussed in this review provide a potentially novel multi-mechanistic therapeutic strategy for AD. However, future clinical trials need to be conducted to further investigate their beneficial properties and to determine the safety and efficacy of SIRT1 natural activators against AD.

Validating the Mild Behavioral Impairment Checklist in a Cognitive Clinic: Comparisons With the Neuropsychiatric Inventory Questionnaire

OBJECTIVE

To compare the utility of the Mild Behavioral Impairment-Checklist (MBI-C) and Neuropsychiatric Inventory Questionnaire (NPI-Q) to capture NPS in subjective cognitive decline (SCD), mild cognitive impairment (MCI), and dementia.

METHODS

In this cross-sectional memory clinic study, linear regression models compared MBI-C (n = 474) and NPI-Q (n = 1040) scores in relation to Montreal Cognitive Assessment (MoCA) score.

RESULTS

MBI prevalence was 37% in subjective cognitive decline, 54% in mild cognitive impairment, and 62% in dementia. Worse diagnostic status was associated with higher MBI-C and NPI-Q score (P < .001), lower MoCA (P < .001), and greater age (P < .001). Higher MBI-C (β -.09; 95% CI -.13, -.05) and NPI-Q (β -.17; 95% CI -.23, -.10) scores were associated with lower MoCA scores, with psychosis most strongly associated (β -1.11; 95% CI -1.56, -.65 vs β -1.14; 95% CI -1.55, -.73).

CONCLUSIONS

The MBI-C captures global and domain-specific NPS across cognitive stages. Both the MBI-C and NPI-Q have utility in characterizing NPS.

Preliminary Validation Study of the French-Quebec Version of the Mild Behavioral Impairment Checklist

BACKGROUND

Alzheimer disease dementia may be preceded by cognitive stages during which behavioral and psychological changes can occur. More precisely, behavioral symptoms may be observed during the subjective cognitive decline (SCD) or the mild cognitive impairment (MCI) stages; these symptoms can be measured using the Mild Behavioral Impairment Checklist (MBI-C).

OBJECTIVE

To validate the French-Quebec version of the MBI-C in individuals ages 60-85 years.

METHOD

The sample included 60 participants (20 MCI, 20 SCD, 20 cognitively healthy) and their informants. To assess the discriminant validity of the MBI-C, a Kruskal-Wallis analysis with a multiple comparisons test was performed on the MBI-C Total score. To determine convergent validity, Spearman correlations were calculated between the MBI-C subscales and a set of validation tools. Finally, test-retest reliability was assessed with Spearman correlations of MBI-C scores between two test sessions.

RESULTS

All of the analyses indicated satisfactory psychometric properties for the French-Quebec version of the MBI-C.

CONCLUSION

This validation study reveals that the MBI-C can be used successfully in dementia risk assessments. From now on, the use of a validated MBI-C will be possible in the French-Quebec population.

Whey Protein Hydrolysate Renovates Age-Related and Scopolamine-Induced Cognitive Impairment

Whey protein and its hydrolysates are ubiquitously applied in the food system. However, their effect on cognitive impairment remains unclear. This study aimed to investigate the potential ability of whey protein hydrolysate (WPH) to ameliorate cognitive degeneration. WPH intervention in Crl:CD1 (ICR, Institute for cancer research) mice and aged C57BL/6J mice in a scopolamine-induced cognitive impairment model for 10 days were evaluated. Behavioral tests indicated that WPH intervention improved the cognitive abilities in ICR and aged C57BL/6J mice (p < 0.05). Scopolamine enhanced the Aβ_1-42 level in the brain tissue, and the WPH intervention exhibited a similar therapeutic effect to donepezil in ICR mice. A noticeable reduction occurred in serum Aβ_1-42 level of aged mice treated with WPH. The histopathological study of the hippocampus showed that WPH intervention alleviates neuronal damage. Hippocampus proteomic analysis suggested possible mechanisms of WPH action. The relative abundance of Christensenellaceae, a gut microbe related to Alzheimer's disease, was altered by WPH intervention. This study demonstrated that short-term WPH intake protected against memory impairment induced by scopolamine and aging.

Plasma Phosphorylated Tau at Threonine 181 and Neuropsychiatric Symptoms in Preclinical and Prodromal Alzheimer Disease

BACKGROUND AND OBJECTIVES

Plasma phosphorylated tau at threonine 181 (p-tau181), a well-validated marker of Alzheimer disease (AD) pathologic change, could be a more efficient way to diagnose AD than invasive or expensive biomarkers requiring CSF or PET. In some individuals, neuropsychiatric symptoms (NPS) are the earliest manifestation of AD, observed in advance of clear cognitive decline. However, the few studies assessing AD biomarkers in association with NPS have often had imprecision in capturing behavioral symptoms that represent sequelae of neurodegenerative disease. Thus, the mild behavioral impairment (MBI) construct was developed, framing NPS in a way to improve the precision of risk estimates for disease. MBI core criteria stipulate that NPS emerge de novo in later life and persist for at least 6 months. Here, cross-sectionally and longitudinally, we investigated associations of MBI with p-tau181, neuropsychological test performance, and incident AD.

METHODS

Cognitively unimpaired and mild cognitive impairment (MCI) Alzheimer's Disease Neuroimaging Initiative participants were selected. MBI status was derived from the Neuropsychiatric Inventory (NPI) using a published algorithm. NPI total scores at baseline and year 1 visits were used to operationalize MBI (score >0 at both visits), NPS not meeting the MBI criteria (NPS-not-MBI, score >0 at only 1 visit), and no NPS (score = 0 at both visits). Linear regressions were fitted for cross-sectional analyses; multilevel linear mixed-effects and Cox proportional hazards models were implemented to examine the longitudinal associations of MBI with changes in p-tau181 and cognition and incident dementia.

RESULTS

The sample included 571 participants (age 72.2 years, 46.8% female, 64.8% MCI). Cross-sectionally (β = 8.1%, 95% CI 1.4%-15.2%, p = 0.02), MBI was associated with higher plasma p-tau181 levels compared with no NPS; NPS-not-MBI was not. Longitudinally, MBI was associated with higher p-tau181 (β = 0.014%, 95% CI 0.003-0.026, p = 0.02), in addition to a decline in memory and executive function. Survival analyses demonstrated a 3.92-fold greater dementia incidence in MBI, with no significant differences between NPS-not-MBI and no NPS.

DISCUSSION

These findings extend the evidence base that MBI is associated with elevated risk of cognitive decline and dementia and a sequela of emerging Alzheimer-related proteinopathies. MBI offers a substantial improvement over current approaches that explore behavior as a proxy marker for Alzheimer-related proteinopathies, with both clinical and AD trial enrichment implications.

Serious Games for Learning Among Older Adults With Cognitive Impairment: Systematic Review and Meta-analysis (Preprint).. [DOI: 10.2196/preprints.43607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

BACKGROUND

Learning disabilities are among the major cognitive impairments caused by aging. Among the interventions used to improve learning among older adults are serious games, which are participative electronic games designed for purposes other than entertainment. Although some systematic reviews have examined the effectiveness of serious games on learning, they are undermined by some limitations, such as focusing on older adults without cognitive impairments, focusing on particular types of serious games, and not considering the comparator type in the analysis.

OBJECTIVE

This review aimed to evaluate the effectiveness of serious games on verbal and nonverbal learning among older adults with cognitive impairment.

METHODS

Eight electronic databases were searched to retrieve studies relevant to this systematic review and meta-analysis. Furthermore, we went through the studies that cited the included studies and screened the reference lists of the included studies and relevant reviews. Two reviewers independently checked the eligibility of the identified studies, extracted data from the included studies, and appraised their risk of bias and the quality of the evidence. The results of the included studies were summarized using a narrative synthesis or meta-analysis, as appropriate.

RESULTS

Of the 559 citations retrieved, 11 (2%) randomized controlled trials (RCTs) ultimately met all eligibility criteria for this review. A meta-analysis of 45% (5/11) of the RCTs revealed that serious games are effective in improving verbal learning among older adults with cognitive impairment in comparison with no or sham interventions (<i>P</i>=.04), and serious games do not have a different effect on verbal learning between patients with mild cognitive impairment and those with Alzheimer disease (<i>P</i>=.89). A meta-analysis of 18% (2/11) of the RCTs revealed that serious games are as effective as conventional exercises in promoting verbal learning (<i>P</i>=.98). We also found that serious games outperformed no or sham interventions (4/11, 36%; <i>P</i>=.03) and conventional cognitive training (2/11, 18%; <i>P</i>&lt;.001) in enhancing nonverbal learning.

CONCLUSIONS

Serious games have the potential to enhance verbal and nonverbal learning among older adults with cognitive impairment. However, our findings remain inconclusive because of the low quality of evidence, the small sample size in most of the meta-analyzed studies (6/8, 75%), and the paucity of studies included in the meta-analyses. Thus, until further convincing proof of their effectiveness is offered, serious games should be used to supplement current interventions for verbal and nonverbal learning rather than replace them entirely. Further studies are needed to compare serious games with conventional cognitive training and conventional exercises, as well as different types of serious games, different platforms, different intervention periods, and different follow-up periods.

CLINICALTRIAL

PROSPERO CRD42022348849; https://tinyurl.com/y6yewwfa

Plasma β-Amyloid in Mild Behavioural Impairment - Neuropsychiatric Symptoms on the Alzheimer's Continuum

INTRODUCTION

Simple markers are required to recognize older adults at higher risk for neurodegenerative disease. Mild behavioural impairment (MBI) and plasma β-amyloid (Aβ) have been independently implicated in the development of incident cognitive decline and dementia. Here we studied the associations between MBI and plasma Aβ₄₂/Aβ₄₀.

METHODS

Participants with normal cognition (n = 86) or mild cognitive impairment (n = 53) were selected from the Alzheimer's Disease Neuroimaging Initiative. MBI scores were derived from Neuropsychiatric Inventory items. Plasma Aβ₄₂/Aβ₄₀ ratios were assayed using mass spectrometry. Linear regressions were fitted to assess the association between MBI total score as well as MBI domain scores with plasma Aβ₄₂/Aβ₄₀.

RESULTS

Lower plasma Aβ₄₂/Aβ₄₀ was associated with higher MBI total score (p = 0.04) and greater affective dysregulation (p = 0.04), but not with impaired drive/motivation (p = 0.095) or impulse dyscontrol (p = 0.29) MBI domains.

CONCLUSION

In persons with normal cognition or mild cognitive impairment, MBI was associated with low plasma Aβ₄₂/Aβ₄₀. Incorporating MBI into case detection may help capture preclinical and prodromal Alzheimer's disease.

Psychosis in Alzheimer disease - mechanisms, genetics and therapeutic opportunities

Psychosis is a common and distressing symptom in people with Alzheimer disease, and few safe and effective treatments are available. However, new approaches to symptom assessment and treatment are beginning to drive the field forward. New nosological perspectives have been provided by incorporating the emergence of psychotic symptoms in older adults - even in advance of dementia - into epidemiological and neurobiological frameworks as well as into diagnostic and research criteria such as the International Psychogeriatric Association criteria for psychosis in neurocognitive disorders, the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment (ISTAART) research criteria for psychosis in neurodegenerative disease, and the ISTAART criteria for mild behavioural impairment. Here, we highlight the latest findings in genomics, neuroimaging and neurobiology that are informing approaches to drug discovery and repurposing. Current pharmacological and non-pharmacological treatment options are discussed, with a focus on safety and precision medicine. We also explore trial data for pimavanserin, a novel agent that shows promise for the treatment of psychosis in people with dementia, and discuss existing agents that might be useful but need further exploration such as escitalopram, lithium, cholinesterase inhibitors and vitamin D. Although the assessment and management of psychosis in people with dementia remain challenging, new opportunities are providing direction and hope to the field.

Apathy as a Treatment Target in Alzheimer's Disease: Implications for Clinical Trials

Apathy is one of the most prevalent, stable and persistent neuropsychiatric symptom across the neurocognitive disorders spectrum. Recent advances in understanding of phenomenology, neurobiology and intervention trials highlight apathy as an important target for clinical intervention. We conducted a comprehensive review and critical evaluation of recent advances to determine the evidence-based suggestions for future trial designs. This review focused on 4 key areas: 1) pre-dementia states; 2) assessment; 3) mechanisms/biomarkers and 4) treatment/intervention efficacy. Considerable progress has been made in understanding apathy as a treatment target and appreciating pharmacological and non-pharmacological apathy treatment interventions. Areas requiring greater investigation include: diagnostic procedures, symptom measurement, understanding the biological mechanisms/biomarkers of apathy, and a well-formed approach to the development of treatment strategies. A better understanding of the subdomains and biological mechanisms of apathy will advance apathy as a treatment target for clinical trials.

Diagnosing Alzheimer's Disease from Circulating Blood Leukocytes Using a Fluorescent Amyloid Probe

BACKGROUND

Toxic amyloid-β (Aβ) peptides aggregate into higher molecular weight assemblies and accumulate not only in the extracellular space, but also in the walls of blood vessels in the brain, increasing their permeability, and promoting immune cell migration and activation. Given the prominent role of the immune system, phagocytic blood cells may contact pathological brain materials.

OBJECTIVE

To develop a novel method for early Alzheimer's disease (AD) detection, we used blood leukocytes, that could act as "sentinels" after trafficking through the brain microvasculature, to detect pathological amyloid by labelling with a conformationally-sensitive fluorescent amyloid probe and imaging with confocal spectral microscopy.

METHODS

Formalin-fixed peripheral blood mononuclear cells (PBMCs) from cognitively healthy control (HC) subjects, mild cognitive impairment (MCI) and AD patients were stained with the fluorescent amyloid probe K114, and imaged. Results were validated against cerebrospinal fluid (CSF) biomarkers and clinical diagnosis.

RESULTS

K114-labeled leukocytes exhibited distinctive fluorescent spectral signatures in MCI/AD subjects. Comparing subjects with single CSF biomarker-positive AD/MCI to negative controls, our technique yielded modest AUCs, which improved to the 0.90 range when only MCI subjects were included in order to measure performance in an early disease state. Combining CSF Aβ 42 and t-Tau metrics further improved the AUC to 0.93.

CONCLUSION

Our method holds promise for sensitive detection of AD-related protein misfolding in circulating leukocytes, particularly in the early stages of disease.

The Efficacy and Safety of Alzheimer's Disease Therapies: An Updated Umbrella Review

BACKGROUND

Evidence summaries for efficacy and safety of frequently employed treatments of Alzheimer's disease (AD) are sparse.

OBJECTIVE

We aimed to perform an updated umbrella review to identify an efficacious and safe treatment for AD patients.

METHODS

We conducted a search for meta-analyses and systematic reviews on the Embase, PubMed, The Cochrane Library, and Web of Science to address this knowledge gap. We examined the cognitive functions, behavioral symptoms, global clinical assessment, and Activities of Daily Living as efficacy endpoints, and the incidence of adverse events as safety profiles.

RESULTS

Sixteen eligible papers including 149 studies were included in the umbrella review. The results showed that AChE inhibitors (donepezil, galantamine, rivastigmine, Huperzine A), Ginkgo biloba, and cerebrolysin appear to be beneficial for cognitive, global performances, and activities of daily living in patients with AD. Furthermore, anti-Aβ agents are unlikely to have an important effect on slowing cognitive or functional impairment in mild to moderate AD.

CONCLUSION

Our study demonstrated that AChE inhibitors, Ginkgo biloba, and cerebrolysin are the optimum cognitive and activities of daily living medication for patients with AD.

Neural correlates of the impulse dyscontrol domain of mild behavioral impairment

OBJECTIVES

Agitation and aggression are common in dementia and pre-dementia. The dementia risk syndrome mild behavioral impairment (MBI) includes these symptoms in the impulse dyscontrol domain. However, the neural circuitry associated with impulse dyscontrol in neurodegenerative disease is not well understood. The objective of this work was to investigate if regional micro- and macro-structural brain properties were associated with impulse dyscontrol symptoms in older adults with normal cognition, mild cognitive impairment, and Alzheimer's disease (AD).

METHODS

Clinical, neuropsychiatric, and T1-weighted and diffusion-tensor magnetic resonance imaging (DTI) data from 80 individuals with and 123 individuals without impulse dyscontrol were obtained from the AD Neuroimaging Initiative. Linear mixed effect models were used to assess if impulse dyscontrol was related to regional DTI and volumetric parameters.

RESULTS

Impulse dyscontrol was present in 17% of participants with NC, 43% with MCI, and 66% with AD. Impulse dyscontrol was associated with: (1) lower fractional anisotropy (FA), and greater mean, axial, and radial diffusivity in the fornix; (2) lesser FA and greater radial diffusivity in the superior fronto-occipital fasciculus; (3) greater axial diffusivity in the cingulum; (4) greater axial and radial diffusivity in the uncinate fasciculus; (5) gray matter atrophy, specifically, lower cortical thickness in the parahippocampal gyrus.

CONCLUSION

Our findings provide evidence that well-established atrophy patterns of AD are prominent in the presence of impulse dyscontrol, even when disease status is controlled for, and possibly in advance of dementia. Our findings support the growing evidence for impulse dyscontrol symptoms as an early manifestation of AD.

Reliability and Validity of the Chinese Version of Mild Behavioral Impairment Checklist in Mild Cognitive Impairment and Mild Alzheimer's Disease

BACKGROUND

Mild behavioral impairment (MBI) has been proposed as an early manifestation of dementia. The Mild Behavioral Impairment Checklist (MBI-C) may help identify MBI in prodromal and preclinical dementia.

OBJECTIVE

The study aimed to evaluate the reliability and validity of the Chinese version of MBI-C in mild cognitive impairment (MCI) and mild Alzheimer's disease (AD), and to explore the structure of the five factors of the MBI-C in Chinese culture.

METHODS

Sixty dyads of MCI and mild AD (MCI, n = 33; mild AD, n = 35) were recruited. The informants completed the MBI-C and Neuropsychiatric Inventory Questionnaire (NPI-Q) and were interviewed for clinician rating of the NPI. The Cronbach's coefficient was used to measure the structural reliability of the MBI-C. The criterion-validity was evaluated with the correlation coefficient between the MBI-C and the total scores of NPI-Q and NPI. Exploratory factor analysis was conducted to investigate the structure of the MBI-C.

RESULTS

The Cronbach's α coefficient was 0.895. The MBI-C total score was positively correlated with all five domains (r = 0.577∼0.840). The total score of MBI-C was significantly correlated with the total scores of NPI-Q (r = 0.714) and NPI (r = 0.749). Similarly, the five domain scores of MBI-C were significantly correlated with the factor and total scores of NPI-Q (r = 0.312∼0.673) and NPI (r = 0.389∼0.673). The components of each factor in Chinese version of MBI-C were slightly different from those of the a priori defined domains (χ2 = 1818.202, df = 496, p < 0.001).

CONCLUSION

The Chinese version of MBI-C has good reliability and validity, and can be used to evaluate the psychological and behavioral changes in MCI and mild AD.

Associations of Anxiety with Amyloid, Tau, and Neurodegeneration in Older Adults without Dementia: A Longitudinal Study

BACKGROUND

The pathophysiological process of amyloid-β, tau deposition, and neurodegeneration of Alzheimer's disease (AD) begin in a preclinical phase, while anxiety is associated with an increased risk of AD in preclinical phase.

OBJECTIVE

To examine the relationships between anxiety and amyloid-β, tau deposition, and neurodegeneration. To test the hypothesis that anxiety could predict clinical progression in the elderly without dementia.

METHODS

1,400 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database were included in the study and were studied over a median period of 3 years. In multivariable models, the cross-sectional and longitudinal associations between anxiety and amyloid-β PET, tau PET, and FDG PET SUVRs in participants without dementia were explored using Spearman rank correlation, logistic regression model, multiple linear regression model, Kaplan-Meier survival curves, and Cox proportional hazards model. The association between baseline anxiety and clinical progression was also explored.

RESULTS

There was a positive correlation between anxiety and amyloid-β deposition (r = 0.11, p = 0.0017) and a negative correlation between anxiety and neurodegeneration (r = -0.13, p = 0.00022). MCI participants with anxiety showed a faster clinical progression of dementia (HR = 1.56, p = 0.04). Non-anxious participants with more amyloid-β deposition or more severe neurodegeneration displayed accelerated development into anxiety (HR = 2.352, p < 0.0001; HR = 2.254, p < 0.0001).

CONCLUSION

Anxiety was associated with amyloid-β deposition and neurodegeneration in non-dementia elderly. Anxiety in MCI predicted conversion to dementia. Anxiety may play a selective role and prediction of disease progression in the early phase of AD.

Associations of AT(N) biomarkers with neuropsychiatric symptoms in preclinical Alzheimer's disease and cognitively unimpaired individuals

The development of in vivo biomarkers of Alzheimer's disease (AD) has advanced the diagnosis of AD from a clinical syndrome to a biological construct. The preclinical stage of AD continuum is defined by the identification of AD biomarkers crossing the pathological threshold in cognitively unimpaired individuals. While neuropsychiatric symptoms (NPS) are non-cognitive symptoms that are increasingly recognized as early manifestations of AD, the associations of NPS with AD pathophysiology in preclinical AD remain unclear. Here, we review the associations between NPS and AD biomarkers amyloid-β (Aβ), tau and neurodegeneration in preclinical AD and cognitively-unimpaired individuals in 19 eligible English-language publications (8 cross-sectional studies, 10 longitudinal, 1 both cross-sectional and longitudinal). The cross-sectional studies have consistently shown that NPS, particularly depressive and anxiety symptoms, are associated with higher Aβ. The longitudinal studies have suggested that greater NPS are associated with higher Aβ and cognitive decline in cognitively unimpaired subjects over time. However, most of the studies have either cross-sectionally or longitudinally shown no association between NPS and tau pathology. For the association of NPS and neurodegeneration, two studies have shown that the cerebrospinal fluid total-tau is linked to longitudinal increase in NPS and that the NPS may predict longitudinal metabolic decline in preclinical AD, respectively. However, evidence for the association between atrophy and NPS in preclinical AD is less consistent. Therefore, future longitudinal studies with well-designed methodologies and NPS measurements are required not only to determine the relationship among AT(N) biomarkers, NPS and cognitive decline, but also to elucidate the contribution of comorbid pathology to preclinical AD.

Association Between BDNF Val66Met Polymorphism and Mild Behavioral Impairment in Patients With Parkinson's Disease

Neuropsychiatric symptoms (NPS) are common in Parkinson's disease (PD) and have demonstrated an association with the p. Val66Met, a polymorphism in the BDNF gene. Mild behavioral impairment (MBI) is a validated syndrome describing emergent and persistent NPS in older adults as a marker of potential cognitive decline and dementia. This study investigated if PD patients with the Met allele were more likely to have MBI and whether they had impairments in specific domains of MBI using the Mild Behavioral Impairment Checklist (MBI-C) as the MBI ascertainment tool. One hundred forty-six PD patients were screened for neuropsychiatric and cognitive impairments with the MBI-C and the Montreal Cognitive Assessment (MoCA). All participants were genotyped for the BDNF p.Val66Met single-nucleotide polymorphism (SNP) using TaqMan Genotyping Assay. Statistical analysis was performed using multiple linear and logistic regression models. Met carriers had a 2 times higher likelihood of being MBI positive (MBI-C total score ≥8) than Val carriers. Met carriers had significantly higher MBI-C total scores and significantly greater impairments in the mood/anxiety and the psychotic domains of MBI-C compared to Val carriers. These findings indicate that the BDNF Met allele is associated with a higher neuropsychiatric burden in PD.

Mild Behavioral Impairment and Subjective Cognitive Decline Predict Cognitive and Functional Decline

BACKGROUND

Mild behavioral impairment (MBI) and subjective cognitive decline (SCD) are dementia risk states, and potentially represent neurobehavioral and neurocognitive manifestations, respectively, of early stage neurodegeneration. Both MBI and SCD predict incident cognitive decline and dementia, are associated with known dementia biomarkers, and are both represented in the NIA-AA research framework for AD in Stage 2 (preclinical disease).

OBJECTIVE

To assess the associations of MBI and SCD, alone and in combination, with incident cognitive and functional decline in a population of older adults. We tested the hypothesis that MBI and SCD confer additive risk for decline.

METHODS

Cognitively normal participants were followed up annually at Alzheimer's Disease Centers. Logistic regression assessed the relationship between baseline classification (MBI-SCD-, MBI-SCD+, MBI+SCD-, or MBI+SCD+) and 3-year outcome.

RESULTS

Of 2,769 participants (mean age=76), 1,536 were MBI-SCD-, 254 MBI-SCD+, 743 MBI+SCD-, and 236 MBI+SCD+. At 3 years, 349 (12.6%) declined to CDR >0, including 23.1% of the MBI+group, 23.5% of the SCD+group, and 30.9% of the intersection group of both MBI+and SCD+participants. Compared to SCD-MBI-, we observed an ordinal progression in risk (ORs [95% CI]): 3.61 [2.42-5.38] for MBI-SCD+ (16.5% progression), 4.76 [3.57-6.34] for MBI+SCD- (20.7%), and 8.15 [5.71-11.64] for MBI+SCD+(30.9%).

CONCLUSION

MBI and SCD together were associated with the greatest risk of decline. These complementary dementia risk syndromes can be used as simple and scalable methods to identify high-risk patients for workup or for clinical trial enrichment.

Prevalence of mild behavioural impairment: a systematic review and meta-analysis

AIM

Mild behavioural impairment (MBI) is a neurobehavioural syndrome characterized by emergent neuropsychiatric symptoms in later life. There has been no systematic review or meta-analysis on the prevalence of MBI. The main aim of the study is to calculate the pooled prevalence of MBI.

METHODS

A search of the literature on MBI in mild cognitive impairment (MCI), cognitively normal (CN), and subjective cognitive impairment (SCI) and CN but at risk (CN-AR) subjects published between 1 January 2003 and 28 September 2020 was conducted. Meta-analysis using a random effects model was performed to determine the pooled estimate of the prevalence of MBI. Meta-regression was performed to identify factors contributing to the variance of prevalence rate. A systematic review was also performed to study the impact of MBI in cognitive outcomes and its correlation to the pathology and genetics of Alzheimer's disease.

RESULTS

Eleven studies conducted among 15 689 subjects underwent meta-analysis, revealing the pooled prevalence of MBI to be 33.5% (95% confidence interval (CI): 22.6%-46.6%). Seven studies conducted among 1358 MCI subjects underwent meta-analysis, revealing the pooled prevalence to be 45.5% (95%CI: 36.1%-55.3%). Four studies conducted among 13 153 CN subjects underwent meta-analysis, revealing the pooled prevalence to be 17.0% (95%CI: 7.2%-34.9%). Five studies conducted among 1158 SCI or CN-AR subjects underwent meta-analysis, revealing the pooled prevalence to be 35.8% (95%CI: 21.4%-53.2%). A systematic review of 13 studies showed that MBI has a significant impact on cognitive deterioration and is associated with the pathology and genetics of Alzheimer's disease.

CONCLUSIONS

In MCI, CN, and SCI and CN-AR subjects, MBI is common. Our finding is potentially useful in planning future clinical trials.

Mild behavioral impairment is associated with β-amyloid but not tau or neurodegeneration in cognitively intact elderly individuals

INTRODUCTION

Mild behavioral impairment (MBI) is characterized by the emergence of neuropsychiatric symptoms in elderly persons. Here, we examine the associations between MBI and Alzheimer's disease (AD) biomarkers in asymptomatic elderly individuals.

METHODS

Ninety-six cognitively normal elderly individuals underwent MRI, [¹⁸ F]AZD4694 β-amyloid-PET, and [¹⁸ F]MK6240 tau-PET. MBI was assessed using the MBI Checklist (MBI-C). Pearson's correlations and voxel-based regressions were used to evaluate the relationship between MBI-C score and [¹⁸ F]AZD4694 retention, [¹⁸ F]MK6240 retention, and gray matter (GM) volume.

RESULTS

Pearson correlations revealed a positive relationship between MBI-C score and global and striatal [¹⁸ F]AZD4694 standardized uptake value ratios (SUVRs). Voxel-based regression analyses revealed a positive correlation between MBI-C score and [¹⁸ F]AZD4694 retention. No significant correlations were found between MBI-C score and [¹⁸ F]MK6240 retention or GM volume.

CONCLUSION

We demonstrate for the first time a link between MBI and early AD pathology in a cognitively intact elderly population, supporting the use of the MBI-C as a metric to enhance clinical trial enrolment.

CCCDTD5 recommendations on early non cognitive markers of dementia: A Canadian consensus

Introduction

Cognitive impairment is the hallmark of Alzheimer's disease (AD) and related dementias. However, motor decline has been recently described as a prodromal state that can help to detect at‐risk individuals. Similarly, sensory changes, sleep and behavior disturbances, and frailty have been associated with higher risk of developing dementia. These clinical findings, together with the recognition that AD pathology precedes the diagnosis by many years, raises the possibility that non‐cognitive changes may be early and non‐invasive markers for AD or, even more provocatively, that treating non‐cognitive aspects may help to prevent or treat AD and related dementias.

Methods

A subcommittee of the Canadian Consensus Conference on Diagnosis and Treatment of Dementia reviewed areas of emerging evidence for non‐cognitive markers of dementia. We examined the literature for five non‐cognitive domains associated with future dementia: motor, sensory (hearing, vision, olfaction), neuro‐behavioral, frailty, and sleep. The Grading of Recommendations Assessment, Development, and Evaluation system was used to assign the strength of the evidence and quality of the recommendations. We provide recommendations to primary care clinics and to specialized memory clinics, answering the following main questions: (1) What are the non‐cognitive and functional changes associated with risk of developing dementia? and (2) What is the evidence that sensory, motor, behavioral, sleep, and frailty markers can serve as potential predictors of dementia?

Results

Evidence supported that gait speed, dual‐task gait speed, grip strength, frailty, neuropsychiatric symptoms, sleep measures, and hearing loss are predictors of dementia. There was insufficient evidence for recommending assessing olfactory and vision impairments as a predictor of dementia.

Conclusions

Non‐cognitive markers can assist in identifying people at risk for cognitive decline or dementia. These non‐cognitive markers may represent prodromal symptoms and several of them are potentially amenable to treatment that might delay the onset of cognitive decline.

Agitation and impulsivity in mid and late life as possible risk markers for incident dementia

To identify knowledge gaps regarding new-onset agitation and impulsivity prior to onset of cognitive impairment or dementia the International Society to Advance Alzheimer's Research and Treatment Neuropsychiatric Syndromes (NPS) Professional Interest Area conducted a scoping review. Extending a series of reviews exploring the pre-dementia risk syndrome Mild Behavioral Impairment (MBI), we focused on late-onset agitation and impulsivity (the MBI impulse dyscontrol domain) and risk of incident cognitive decline and dementia. This scoping review of agitation and impulsivity pre-dementia syndromes summarizes the current biomedical literature in terms of epidemiology, diagnosis and measurement, neurobiology, neuroimaging, biomarkers, course and prognosis, treatment, and ongoing clinical trials. Validations for pre-dementia scales such as the MBI Checklist, and incorporation into longitudinal and intervention trials, are needed to better understand impulse dyscontrol as a risk factor for mild cognitive impairment and dementia.

Profile of mild behavioral impairment and factor structure of the Mild Behavioral Impairment Checklist in cognitively normal older adults

OBJECTIVES

In this large population study, we set out to examine the profile of mild behavioral impairment (MBI) by using the Mild Behavioral Impairment Checklist (MBI-C) and to explore its factor structure when employed as a self-reported and informant-rated tool.

DESIGN

This was a population-based cohort study.

SETTING

Participants were recruited from the Platform for Research Online to Investigate Genetics and Cognition in Aging study (https://www.protect-exeter.org.uk).

PARTICIPANTS

A total of 5,742 participant-informant dyads participated in the study.

MEASUREMENTS

Both participants and informants completed the MBI-C. The factor structure of the MBI-C was evaluated by exploratory factor analysis.

RESULTS

The most common MBI-C items, as rated by self-reported and informants, related to affective dysregulation (mood/anxiety symptoms), being present in 34% and 38% of the sample, respectively. The least common items were those relating to abnormal thoughts and perception (psychotic symptoms) (present in 3% and 6% of the sample, respectively). Only weak correlations were observed between self-reported and informant-reported MBI-C responses. Exploratory factor analysis for both sets of respondent answers indicated that a five-factor solution for the MBI-C was appropriate, reflecting the hypothesized structure of the MBI-C.

CONCLUSION

This is the largest and most detailed report on the frequency of MBI symptoms in a nondementia sample. The full spectrum of MBI symptoms was present in our sample, whether rated by self-reported or informant report. However, we show that the MBI-C performs differently in self-reported versus informant-reported situations, which may have important implications for the use of the questionnaire in clinic and research.

Recent Studies on Design and Development of Drugs Against Alzheimer's Disease (AD) Based on Inhibition of BACE-1 and Other AD-causative Agents

BACKGROUND

Alzheimer's disease (AD) is one of the neurodegenerative diseases and has been hypothesized to be a protein misfolding disease. In the generation of AD, β-secretase, γ-secretase, and tau protein play an important role. A literature search reflects ever increasing interest in the design and development of anti-AD drugs targeting β-secretase, γ-secretase, and tau protein.

OBJECTIVE

The objective is to explore the structural aspects and role of β-secretase, γ-secretase, and tau protein in AD and the efforts made to exploit them for the design of effective anti-AD drugs.

METHODS

The manuscript covers the recent studies on design and development of anti-AD drugs exploiting amyloid and cholinergic hypotheses.

RESULTS

Based on amyloid and cholinergic hypotheses, effective anti-AD drugs have been searched out in which non-peptidic BACE1 inhibitors have been most prominent.

CONCLUSION

Further exploitation of the structural aspects and the inhibition mechanism for β-secretase, γ-secretase, and tau protein and the use of cholinergic hypothesis may lead still more potent anti-AD drugs.

Using Machine Learning to Predict Dementia from Neuropsychiatric Symptom and Neuroimaging Data

BACKGROUND

Machine learning (ML) is a promising technique for patient-specific prediction of mild cognitive impairment (MCI) and dementia development. Neuropsychiatric symptoms (NPS) might improve the accuracy of ML models but have barely been used for this purpose.

OBJECTIVES

To investigate if baseline mild behavioral impairment (MBI) status used for NPS quantification along with brain morphology features are predictive of follow-up diagnosis, median 40 months later in patients with normal cognition (NC) or MCI.

METHOD

Baseline neuroimaging, neuropsychiatric, and clinical data from 102 individuals with NC and 239 with MCI were extracted from the Alzheimer's Disease Neuroimaging Initiative database. Neuropsychiatric inventory questionnaire items were transformed to MBI domains using a published algorithm. Diagnosis at latest follow-up was used as the outcome variable and ground truth classification. A logistic model tree classifier combined with information gain feature selection was trained to predict follow-up diagnosis.

RESULTS

In the binary classification (NC versus MCI/AD), the optimal ML model required only two features from over 200, MBI total score and left hippocampal volume. These features correctly classified participants as remaining normal or developing cognitive impairment with 84.4% accuracy (area under the receiver operating characteristics curve [ROC-AUC] = 0.86). Seven features were selected for the three-class model (NC versus MCI versus dementia) achieving an accuracy of 58.8% (ROC-AUC=0.73).

CONCLUSION

Baseline NPS, categorized for MBI domain and duration, have prognostic utility in addition to brain morphology measures for predicting diagnosis change using ML. MBI total score, followed by impulse dyscontrol and affective dysregulation were most predictive of future diagnosis.

Plasma Neurofilament Light: A Marker of Neurodegeneration in Mild Behavioral Impairment

BACKGROUND

Assessing neuropsychiatric symptoms (NPS) in older adults is important for determining dementia risk. Mild behavioral impairment (MBI) is an at-risk state for cognitive decline and dementia, characterized by emergent NPS in later life. MBI has significantly higher dementia incidence than late life psychiatric conditions. However, its utility as a proxy for neurodegeneration has not been demonstrated. Plasma neurofilament light (NfL) is a validated biomarker of axonal damage, and has been shown to associate with hallmarks of neurodegeneration.

OBJECTIVE

The purpose of this investigation was to identify associations between NfL rate of change and the presence of MBI symptomatology.

METHODS

We evaluated the association of MBI with changes in NfL in a cohort (n = 584; MBI + n = 190, MBI- n = 394) of non-demented participants from the Alzheimer's Disease Neuroimaging Initiative. MBI was determined by transforming Neuropsychiatric Inventory Questionnaire items using a published algorithm. Change in NfL was calculated over 2 years.

RESULTS

Time*MBI status was the only significant interaction to predict change in NfL concentrations (F(1,574) = 4.59, p = 0.032), even after controlling for age, mild cognitive impairment, and demographics. Analyses reclassifying 64 participants with new onset MBI over 2 years similarly demonstrated greater increases in NfL (F(1,574) = 5.82, p = 0.016).

CONCLUSION

These findings suggest MBI is a clinical proxy of early phase neurodegeneration with putative utility in identifying those at dementia risk. MBI can be used as a case ascertainment approach to capture those at high risk for cognitive decline and dementia, and is an important construct for clinicians dealing with cognitive and neuropsychiatric symptomatology in older adults.

Time course of neuropsychiatric symptoms and cognitive diagnosis in National Alzheimer's Coordinating Centers volunteers

INTRODUCTION

Neuropsychiatric symptoms (NPSs) are nearly universal in cognitive disorders. The mild behavioral impairment construct postulates that NPS may be the first symptom of impending dementia.

METHODS

Participants were cognitively normal volunteers followed up approximately annually at Alzheimer's Disease Centers, who were assessed on the Neuropsychiatric Inventory and had at least one follow-up visit during which they were diagnosed with mild cognitive impairment (MCI) or dementia. Descriptive statistics were used to determine sequencing of NPS presence with cognitive diagnoses.

RESULTS

Data were available for 1998 participants who progressed to MCI or dementia. Over 59% developed NPS before the diagnosis of any cognitive disorder. Depression and irritability were the most common NPSs to precede cognitive diagnoses (24 and 21%, respectively).

DISCUSSION

NPSs precede a cognitive diagnosis in most people who develop cognitive decline, both MCI and dementia. These individuals are an important group to focus clinical and research efforts.

Non-pharmacological therapeutic strategy options for patients with dementia based on cognitive function-A Bayesian network meta-analysis of randomized controlled trials

Dementia represents one of the most common neurodegenerative disorders in older adults. However, it is still unclear whether non-pharmacological therapies (NPTs) are effective or not and which treatment should be preferred. We applied a series of search strategies to identify eligible randomized controlled trials on 1st October, 2018, investigating the effects of NPTs of dementia in the older persons. Pairwise and network meta-analyses were sequentially performed. A total of 31 trials were included, which enrolled 1895 participants and 7 NPTs. Compared with control group, all the NPTs included were statistically beneficial to cognitive function, and our study indicated Comprehensive Therapy(CT) [the surface under the cumulative ranking curve (SUCRA = 92.42%)] might be the best choice for dementia patients. Our study suggests CT might be the optimal NPT for improving the cognitive function of dementia patients. However, the above conclusions need to be further analyzed.

Brain Metabolic Dysfunction in Early Neuropsychiatric Symptoms of Dementia

Neuropsychiatric symptoms (NPS) including behavioral and psychiatric symptoms are common in the dementia stages of Alzheimer's disease (AD) and are associated with poorer outcomes in cognition, functional states, quality of life, and accelerated progression to severe dementia or death. NPS are also increasingly observed in the mild cognitive impairment stage of AD and may predict incipient dementia. As such, there is an emerging conceptual framework, which support NPS as early non-cognitive symptoms of dementia. [18F]fluorodeoxyglucosepositron emission tomography is a technique that is sensitive in detecting resting metabolism associated with NPS in neuropsychiatric conditions, and there is a growing body of literature evaluating the role of NPS as early indicators of brain metabolic dysfunctions in AD. In this mini-review, we examine the frequency and associations of NPS with metabolic dysfunction in the AD continuum, including preclinical, prodromal, and dementia stages of AD. We will also present the validated neurobehavioral syndrome, mild behavioral impairment describes the later life emergence of sustained NPS as an at-risk state for incident cognitive decline and dementia, and an early presentation of neurodegenerative diseases in some. Lastly, we will discuss future directions in the field so as to better understand the neurobiological basis of NPS in the early stages of the AD continuum, and their role in predicting AD pathophysiological progression and incident dementia.

Mild Behavioral Impairment as a Marker of Cognitive Decline in Cognitively Normal Older Adults

OBJECTIVE

Mild behavioral impairment (MBI) is a neurobehavioral syndrome characterized by later life emergent neuropsychiatric symptoms (NPS) that represent an at-risk state for incident cognitive decline and dementia in people with mild cognitive impairment (MCI). We undertook a study to determine whether MBI was associated with progressive changes in neuropsychological performance in people without significant cognitive impairment.

METHODS

A total of 9,931 older adults enrolled in the PROTECT study who did not have MCI or dementia undertook a comprehensive neuropsychological battery measuring attention, reasoning, executive function, and working memory at baseline and 1 year. MBI was ascertained using self-administration of the Mild Behavioral Impairment Checklist at 1 year, and participants were grouped according to MBI status: No Symptoms, Intermediate NPS and MBI. All assessments were completed online, and data analyzed using mixed-effects model repeated measures analysis of covariance.

RESULTS

A total of 949 (10%) people had MBI. These individuals had significantly worse cognitive performance at baseline and significantly greater decline over 1 year in the four composite cognitive scores measuring attentional intensity (F [2,8578] = 3.97; p = 0.019), sustained attention (F [2,8578] = 18.63; p <0.0001), attentional fluctuation (F [2,8578] = 10.13; p <0.0001) and working memory (F [2,9895] = 13.1; p <0.0001).

CONCLUSION

Our novel findings show that MBI is associated with faster decline in attention and working memory in this cognitively normal sample. MBI may be an earlier marker of neurodegenerative disease than MCI, captured at the stage of subjective cognitive decline or before, raising the possibility that MBI represents a novel target for dementia clinical trials or prevention strategies.

The optimal treatment for improving cognitive function in elder people with mild cognitive impairment incorporating Bayesian network meta-analysis and systematic review

It's widely acknowledged that, as a neurodegenerative aging disease representing an intermediate stage between cognitive intactness and Alzheimer's disease (AD), Mild cognitive impairment (MCI) poses an excessive burden on patients' well-being, family members, health-care providers as well as the whole society. This study focuses on three cognitive interventions proposed by Clare and Woods, which are, Cognitive stimulation (CS), Cognitive training (CT) and Cognitive rehabilitation (CR). Our Network meta-analysis (NMA) aims to compar them with one another to determine the optimal cognitive intervention for elderly adults with MCI in improving their cognitive function. We applied extensive strategies to preliminary literature retrieval to identify relevant randomized controlled trials (RCTs) which scrupulously compared any two of the three cognitive interventions with one another or any one of the three with a control group as the placebo or non-active group in treating elder patients with MCI in accordance with Petersen's criteria. Our NMA of cognitive interventions for patients diagnosed with MCI appraised the relative effectiveness of cognitive interventions across trials simultaneously. Our study attempts to summarize available data to suggest that CS (Mean difference [MD] = 0.95, 95% confidence interval [CI]:0.27, 1.70) and CT (MD = 0.70, [CI]:0.11,1.30) were significantly beneficial to MCI patients for improving their cognition status while CR (MD = 0.59, [CI]:-0.30,1.50) scored lowest. Our study suggested CS was most likely to be the best intervention for improving the cognitive function of MCI patients.

Assessing mild behavioral impairment with the mild behavioral impairment checklist in people with subjective cognitive decline

ABSTRACTObjectives:To estimate the prevalence of Mild Behavioral Impairment (MBI) in people with Subjective Cognitive Decline (SCD), and validate the Mild Behavioral Impairment Checklist (MBI-C) with respect to score distribution, sensitivity, specificity, and utility for MBI diagnosis, as well as correlation with other neuropsychological tests.

DESIGN

Correlational study with a convenience sampling. Descriptive, logistic regression, ROC curve, and bivariate correlations analyses were performed.

SETTING

Primary care health centers.

PARTICIPANTS

127 patients with SCD.

MEASUREMENTS

An extensive evaluation, including Questionnaire for Subjective Memory Complaints, Mini-Mental State Examination, Cambridge Cognitive Assessment-Revised, Neuropsychiatric Inventory-Questionnaire (NPI-Q), the Geriatric Depression Scale-15 items (GDS-15), the Lawton and Brody Index and the MBI-C, which was administered by phone to participants' informants.

RESULTS

MBI prevalence was 5.8% in those with SCD. The total MBI-C scoring was low and differentiated people with MBI at a cut-off point of 8.5 (optimizing sensitivity and specificity). MBI-C total scoring correlated positively with NPI-Q, Questionnaire for Subjective Cognitive Complaints (QSCC) from the informant and GDS-15.

CONCLUSIONS

The phone administration of the MBI-C is useful for detecting MBI in people with SCD. The prevalence of MBI in SCD was low. The MBI-C detected subtle Neuropsychiatric symptoms (NPS) that were correlated with scores on the NPI-Q, depressive symptomatology (GDS-15), and memory performance perceived by their relatives (QSCC). Next steps are to determine the predictive utility of MBI in SCD, and its relation to incident cognitive decline over time.

Association of Alzheimer's genetic loci with mild behavioral impairment

Mild behavioral impairment (MBI) describes the emergence of later-life neuropsychiatric symptoms (NPS) as an at-risk state for incident cognitive decline and dementia, and for some as a potential manifestation of prodromal dementia. How NPS mechanistically link to the development of mild cognitive impairment and Alzheimer's disease (AD) is not fully understood, with potential mechanisms including shared risk factors related to both NPS and cognitive impairment, or AD pathology promoting NPS. This is the first exploratory study to examine whether AD genetic loci as a genetic risk score (GRS), or individually, are a shared risk factor with MBI. Participants were 1,226 older adults (aged 72-79; 738 males; 763 normal cognition) from the Personality and Total Health Through Life project. MBI was approximated in accordance with Criterion 1 of the ISTAART-AA diagnostic criteria using a transformation algorithm for the neuropsychiatric inventory. A GRS was constructed from 25 AD risk loci. Binomial logistic regression adjusting for age, gender, and education examined the association between GRS and MBI. A higher GRS and APOE*ε4 were associated with increased likelihood of affective dysregulation. Nominally significant associations were observed between MS4A4A-rs4938933*C and MS4A6A-rs610932*G with a reduced likelihood of affective dysregulation; ZCWPW1-rs1476679*C with a reduced likelihood of social inappropriateness and abnormal perception/thought content; BIN1-rs744373*G and EPHA1-rs11767557*C with higher likelihood of abnormal perception/thought content; NME8-rs2718058*G with a reduced likelihood of decreased motivation. These preliminary findings suggest a common genetic etiology between MBI and traditionally recognized cognitive problems observed in AD and improve our understanding of the pathophysiological features underlying MBI.

Comparison of Cognitive Intervention Strategies for Older Adults With Mild to Moderate Alzheimer's Disease: A Bayesian Meta-analytic Review

OBJECTIVES

We aimed to identify the best form of cognitive therapy among 3 main cognitive interventions of Alzheimer's disease (AD) including cognitive training (CT), cognitive stimulation (CS), and cognitive rehabilitation (CR).

DESIGN

Systematic review and Bayesian network meta-analysis.

SETTING AND PARTICIPANTS

An exhaustive literature search was conducted based on PubMed, Embase, the Cochrane Central Register of Controlled Trials, PsycINFO, the China National Knowledge Infrastructure database, the Chinese Biomedical Literature database, the Wan Fang database, and Web of Science and other database and randomized controlled trials were identified from their inception to May 1, 2018. Older adult participants diagnosed with AD were recruited.

MEASURES

We conducted a Bayesian network meta-analysis (NMA) to rank the included treatments. Cognitive functions were measured based on the Mini-Mental State Examination (MMSE). A series of analyses and assessments, such as the Pairwise meta-analysis and the risk of bias, were performed concurrently.

RESULTS

Only 22 studies were included in our analysis based on a series of rigorous screenings, which comprised 1368 participants. No obvious heterogeneities were found in NMA (I² = 32.7%, P = .07) after the data were pooled. The mean difference (MD) of CT [MD = 2.1, confidence interval [CI]: 1.0, 3.2), CS (MD = 0.92, CI: -0.20, 2.0), and CR (MD = 2.0, CI: 0.73, 3.4) showed that CT and CR could significantly improve cognitive function as measured by MMSE in the treatment group whereas the CS was less effective. CT had the highest probability among the 3 cognitive interventions [the surface under the cumulative ranking curve (SUCRA) = 84.7%], followed by CR (SUCRA = 50.0%) and CS (SUCRA = 47.4%).

CONCLUSIONS/RELEVANCE

Our study indicated that the CT might be the best method for improving the cognitive function of AD patients. The findings from our study may be useful for policy makers and service commissioners when they make choices among different alternatives.

Identification of the optimal cognitive drugs among Alzheimer's disease: a Bayesian meta-analytic review

PURPOSE

The increasing prevalence of Alzheimer's disease (AD) demands more effective drugs, which are still unclear. The aim of this study is to compare the effectiveness of six drugs, such as donepezil, rivastigmine, galantamine, memantine, huperzine-A, and tacrine, in senior AD patients and identify the most effective one to improve patients' cognitive function.

METHODS

A system of search strategies was used to identify relevant studies including randomized controlled trials and clinical controlled trials evaluating the efficacy of six drugs in patients with AD. We updated relevant studies that were published before March 2018 as full-text articles. Using Bayesian network meta-analysis (NMA), we ranked cognitive ability objectively based on Mini-Mental State Examination (MMSE). Pairwise and NMAs were sequentially performed for the efficacy of drugs compared to each drug or control group through the trials included.

RESULTS

Among the 35 trials included, no obvious heterogeneity (I 2=0.0%, P=0.583) was revealed according to the pooled data for cognition in NMA and the mean difference (MD) of memantine (MD=1.7, 95% CI: 0.73, 2.8) showed that the memantine was significantly efficacious in the treatment group in terms of MMSE. Followed by galantamine, huperzine-A, rivastigmine, tacrine, and donepezil.

CONCLUSION

As the first NMA comparing the major drugs in market for AD, our study suggests that memantine might have a more significant benefit on cognition than other five drugs available.

Association of Apathy With Risk of Incident Dementia: A Systematic Review and Meta-analysis

IMPORTANCE

Fear of dementia is pervasive in older people with cognitive concerns. Much research is devoted to finding prognostic markers for dementia risk. Studies suggest apathy in older people may be prodromal to dementia and could be a relevant, easily measurable predictor of increased dementia risk. However, evidence is fragmented and methods vary greatly between studies.

OBJECTIVE

To systematically review and quantitatively synthesize the evidence for an association between apathy in dementia-free older individuals and incident dementia.

DATA SOURCES

Two reviewers conducted a systematic search of Medline, Embase, and PsychINFO databases.

STUDY SELECTION

Inclusion criteria were (1) prospective cohort studies, (2) in general populations or memory clinic patients without dementia, (3) with clear definitions of apathy and dementia, and (4) reporting on the association between apathy and incident dementia.

DATA EXTRACTION AND SYNTHESIS

PRISMA and MOOSE guidelines were followed. Data were extracted by 1 reviewer and checked by a second.

MAIN OUTCOMES AND MEASURES

Main outcomes were pooled crude risk ratios, maximally adjusted reported hazard ratios (HR), and odds ratios (OR) using DerSimonian-Laird random effects models.

RESULTS

The mean age of the study populations ranged from 69.2 to 81.9 years (median, 71.6 years) and the percentage of women ranged from 35% to 70% (median, 53%). After screening 2031 titles and abstracts, 16 studies comprising 7365 participants were included. Apathy status was available for 7299 participants. Studies included populations with subjective cognitive concerns (n = 2), mild cognitive impairment (n = 11), cognitive impairment no dementia (n = 1), or mixed cognitive and no cognitive impairment (n = 2). Apathy was present in 1470 of 7299 participants (20.1%). Follow-up ranged from 1.2 to 5.4 years. In studies using validated apathy definitions (n = 12), the combined risk ratio of dementia for patients with apathy was 1.81 (95% CI, 1.32-2.50; I2 = 76%; n = 12), the hazard ratio was 2.39 (95% CI, 1.27-4.51; I2 = 90%; n = 7), and the odds ratio was 17.14 (95% CI, 1.91-154.0; I2 = 60%; n = 2). Subgroup analyses, meta-regression, and individual study results suggested the association between apathy and dementia weakened with increasing follow-up time, age, and cognitive impairment. Meta-regression adjusting for apathy definition and follow-up time explained 95% of heterogeneity in mild cognitive impairment.

CONCLUSIONS AND RELEVANCE

Apathy was associated with an approximately 2-fold increased risk of dementia in memory clinic patients. Moderate publication bias may have inflated some of these estimates. Apathy deserves more attention as a relevant, cheap, noninvasive, and easily measureable marker of increased risk of incident dementia with high clinical relevance, particularly because these vulnerable patients may forgo health care.

BACE1 Inhibitory Meroterpenoids from Aspergillus terreus

Sixteen 3,5-dimethylorsellinic acid-based (DMOA-based) meroterpenoids, including 10 new compounds, asperterpenes D-M (1-10), were obtained from Aspergillus terreus. The structures and absolute configurations of the new compounds were confirmed by extensive spectroscopy, single-crystal X-ray diffraction analysis, and experimental electronic circular dichroism (ECD) measurements. Compounds 2, 3, and 7 are the first 3,5-dimethylorsellinic acid-based meroterpenoids possessing a unique cis-fused A/B ring system. These new compounds were evaluated for their inhibitory activity against β-site amyloid precursor protein-cleaving enzyme 1 (BACE1). Compounds 2, 3, and 7, the first 3,5-dimethylorsellinic acid-based meroterpenoids possessing cis-fused A/B rings, exhibited significant inhibitory activities against BACE1 with IC₅₀ values of 3.3, 5.9, and 31.7 μM, respectively.

Special Issue on mild behavioral impairment and non-cognitive prodromes to dementia

This Special Issue provides a systematic examination of the neuropsychiatric symptoms (NPS) and non-cognitive prodromes of dementia, with an eye toward validating the construct of mild behavioral impairment (MBI).

New 3,5-dimethylorsellinic acid-based meroterpenoids with BACE1 and AchE inhibitory activities from Aspergillus terreus

Chemical investigation of Aspergillus terreus resulted in the identification of terreusterpenes A–D with potential BACE1 and AchE inhibitory activities.