Application of blood-based biomarkers of Alzheimer's disease in clinical practice: Recommendations from Taiwan Dementia Society

Blood-based biomarkers (BBM) are potentially powerful tools that assist in the biological diagnosis of Alzheimer's disease (AD) in vivo with minimal invasiveness, relatively low cost, and good accessibility. This review summarizes current evidence for using BBMs in AD, focusing on amyloid, tau, and biomarkers for neurodegeneration. Blood-based phosphorylated tau and the Aβ42/Aβ40 ratio showed consistent concordance with brain pathology measured by CSF or PET in the research setting. In addition, glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) are neurodegenerative biomarkers that show the potential to assist in the differential diagnosis of AD. Other pathology-specific biomarkers, such as α-synuclein and TAR DNA-binding protein 43 (TDP-43), can potentially detect AD concurrent pathology. Based on current evidence, the working group from the Taiwan Dementia Society (TDS) achieved consensus recommendations on the appropriate use of BBMs for AD in clinical practice. BBMs may assist clinical diagnosis and prognosis in AD subjects with cognitive symptoms; however, the results should be interpreted by dementia specialists and combining biochemical, neuropsychological, and neuroimaging information. Further studies are needed to evaluate BBMs' real-world performance and potential impact on clinical decision-making.

Interactive Healthcare Robot Using Attention-Based Question-Answer Retrieval and Medical Entity Extraction Models

In healthcare facilities, answering the questions from the patients and their companions about the health problems is regarded as an essential task. With the current shortage of medical personnel resources and an increase in the patient-to-clinician ratio, staff in the medical field have consequently devoted less time to answering questions for each patient. However, studies have shown that correct healthcare information can positively improve patients' knowledge, attitudes, and behaviors. Therefore, delivering correct healthcare knowledge through a question-answering system is crucial. In this article, we develop an interactive healthcare question-answering system that uses attention-based models to answer healthcare-related questions. Attention-based transformer models are utilized to efficiently encode semantic meanings and extract the medical entities inside the user query individually. These two features are integrated through our designed fusion module to match against the pre-collected healthcare knowledge set, so that our system will finally give the most accurate response to the user in real-time. To improve the interactivity, we further introduce a recommendation module and an online web search module to provide potential questions and out-of-scope answers. Experimental results for question-answer retrieval show that the proposed method has the ability to retrieve the correct answer from the FAQ pairs in the healthcare domain. Thus, we believe that this application can bring more benefits to human beings.

Oral microbiome and serological analyses on association of Alzheimer's disease and periodontitis

OBJECTIVE

To investigate the association between Alzheimer's disease (AD) and periodontitis in the aspects of periodontal status, serological markers, and oral microbiome.

MATERIALS AND METHODS

Twenty AD and 20 healthy subjects were enrolled in this age- and gender-matched case-control study. Clinical periodontal parameters and serum biomarkers, including amyloid β42 (Aβ42 ), Tau, phosphorylated Tau (pTau), triglyceride, pro-inflammatory cytokines, and anti-Porphyromonas gingivalis lipopolysaccharide (LPS) antibody were examined. The saliva samples were analyzed for oral microbiome composition.

RESULTS

Alzheimer's disease patients with Clinical Dementia Rating (CDR) ≥1 exhibited significantly more clinical attachment loss (CAL) than those with lower CDR. The levels of serum Tau protein, hsCRP and anti-P. gingivalis LPS antibody were markedly elevated in the AD group compared with the control group. Serum pTau protein level was positively correlated with anti-P. gingivalis LPS antibody titer. Moreover, the increased abundances of Capnocytophaga sp ora clone DZ074, Eubacterium infirmum, Prevotella buccae, and Selenomonas artemidis were detected in the AD group. Interestingly, serum levels of Aβ42, pTau, and anti-P. gingivalis LPS antibody were strongly related to the gene upregulation in human pathogen septicemia.

CONCLUSIONS

Our study suggested the association of periodontal infection and oral microbiome with AD. Further large-scale studies with longitudinal follow-up are warranted.

Safety, tolerability, immunogenicity, and efficacy of UB-311 in participants with mild Alzheimer's disease: a randomised, double-blind, placebo-controlled, phase 2a study

BACKGROUND

Anti-amyloid vaccines may offer a convenient, affordable, and accessible means of preventing and treating Alzheimer's disease. UB-311 is an anti-amyloid-β active immunotherapeutic vaccine shown to be well-tolerated and to have a durable antibody response in a phase 1 trial. This phase 2a study assessed the safety, immunogenicity, and preliminary efficacy of UB-311 in participants with mild Alzheimer's disease.

METHODS

A 78-week, randomised, double-blind, placebo-controlled, parallel-group, multicentre, phase 2a study was conducted in Taiwan. Participants were randomised in a 1:1:1 ratio to receive seven intramuscular injections of UB-311 (Q3M arm), or five doses of U311 with two doses of placebo (Q6M arm), or seven doses of placebo (placebo arm). The primary endpoints were safety, tolerability, and immunogenicity of UB-311. Safety was assessed in all participants who received at least one dose of investigational product. This study was registered at ClinicalTrials.gov (NCT02551809).

FINDINGS

Between 7 December 2015 and 28 August 2018, 43 participants were randomised. UB-311 was safe, well-tolerated, and generated a robust immune response. The three treatment-emergent adverse events (TEAEs) with the highest incidence were injection-site pain (14 TEAEs in seven [16%] participants), amyloid-related imaging abnormality with microhaemorrhages and haemosiderin deposits (12 TEAEs in six [14%] participants), and diarrhoea (five TEAEs in five [12%] participants). A 97% antibody response rate was observed and maintained at 93% by the end of the study across both UB-311 arms.

INTERPRETATION

These results support the continued development of UB-311.

FUNDING

Vaxxinity, Inc. (Formerly United Neuroscience Ltd.).

Substantia nigra nigrosome-1 imaging correlates with the severity of motor symptoms in Parkinson's disease

BACKGROUND

Nigrosome-1 imaging has been used for assisting the diagnosis of Parkinson's disease (PD). We aimed to examine the diagnostic performance of loss of nigrosome-1 in PD and the correlation between the size of the nigrosome-1 and motor severity of PD.

METHODS

We included 237 patients with PD and 165 controls. The motor severity of PD was assessed with the Unified Parkinson's Disease Rating Scale (UPDRS) part III score and Hoehn-Yahr staging. The 3 or 1.5 Tesla susceptibility-weighted imaging combined with a deep-learning algorithm was applied for detecting the loss and the size of nigrosome-1. Clinical correlations and diagnostic performance of size of nigrosome-1 were also investigated.

RESULTS

The mean nigrosome-1 size was significantly smaller in PD patients than in controls (0.06 ± 0.07 cm² vs. 0.20 ± 0.05 cm², P < 0.001). The area under the receiver operating characteristic curve (AUC) of the established model showed 0.94 accuracy (95% confidence interval [CI]: 0.87, 1.01, P < 0.01) in differentiating between the PD and control groups. Moreover, the partial loss of nigrosome-1 detected with SWI had an AUC of 0.96 in discriminating early-stage PD from controls (95% CI: 0.88, 1.02, P < 0.001). After adjusting for age, sex, disease duration, and levodopa equivalent daily dose, the estimated size of nigrosome-1 was negatively associated with the UPDRS part III motor score (ρ = -0.433, P < 0.001), but not with Mini-Mental State Examination scores (ρ = 0.006, P = 0.894).

CONCLUSIONS

The extent of loss and the size of nigrosome-1 may potentially assist in the diagnosis of PD. Nigrosome-1 size reflects the motor severity of PD.

A Multicomponent Cognitive Intervention May Improve Self-Reported Daily Function of Adults With Subjective Cognitive Decline

IMPORTANCE

Limited evidence exists to support cognitive intervention improving the daily function of adults with subjective cognitive decline (SCD).

OBJECTIVE

To examine the preliminary efficacy of a group-based multicomponent cognitive intervention that integrates Lifestyle Redesign® (LR) techniques.

DESIGN

Single-arm two-period crossover trial; 16-wk waiting period, 16-wk intervention, and 16-wk follow-up.

SETTING

Memory clinic in a medical center, Taiwan.

PARTICIPANTS

Purposive sample of adults ages >55 yr with SCD.

INTERVENTION

Sixteen 1.5-hr weekly multicomponent sessions of cognitive training, cognitive rehabilitation, psychological intervention, and lifestyle intervention.

OUTCOMES AND MEASURES

Primary outcomes were (1) self-reported daily function, measured with the Activities of Daily Living Questionnaire (ADLQ) and Cognitive Failure Questionnaire; (2) performance-based daily function, measured with the Brief University of California San Diego Performance-Based Skills Assessment-Traditional Chinese Version; and (3) functional cognition, measured with the Contextual Memory Test (CMT) and Miami Prospective Memory Test. Secondary outcomes included cognitive functions, anxiety, and depression.

RESULTS

Seventeen participants completed the intervention; 4 missed the follow-up. The generalized estimating equations model showed significant changes from baseline to pretest (control) and pretest to posttest (intervention) on the ADLQ (p = .014) and CMT-delayed (p = .003). Effects remained at the 16-wk follow-up. After adjusting for the effects of covariates, the self-reported daily function of participants ages ≤ 63 yr improved more than that of other participants (p = .003).

CONCLUSIONS AND RELEVANCE

Multicomponent cognitive interventions integrating LR techniques may improve self-reported daily function and context-dependent memory function of adults with SCD, with efficacy sustained at follow-up. What This Article Adds: A group-based multicomponent cognitive intervention consisting of cognitive training, cognitive rehabilitation, psychoeducation, and lifestyle intervention may provide benefits for the daily function and cognitive function of adults with SCD.

Machine Learning-Based Classification of Subjective Cognitive Decline, Mild Cognitive Impairment, and Alzheimer's Dementia Using Neuroimage and Plasma Biomarkers

Alzheimer's disease (AD) progresses relentlessly from the preclinical to the dementia stage. The process begins decades before the diagnosis of dementia. Therefore, it is crucial to detect early manifestations to prevent cognitive decline. Recent advances in artificial intelligence help tackle the complex high-dimensional data encountered in clinical decision-making. In total, we recruited 206 subjects, including 69 cognitively unimpaired, 40 subjective cognitive decline (SCD), 34 mild cognitive impairment (MCI), and 63 AD dementia (ADD). We included 3 demographic, 1 clinical, 18 brain-image, and 3 plasma biomarker (Aß_1-42, Aß_1-40, and tau protein) features. We employed the linear discriminant analysis method for feature extraction to make data more distinguishable after dimension reduction. The sequential forward selection method was used for feature selection to identify the 12 best features for machine learning classifiers. We used both random forest and support vector machine as classifiers. The area under the receiver operative curve (AUROC) was close to 0.9 between diseased (combining ADD and MCI) and the controls. AUROC was higher than 0.85 between SCD and controls, 0.90 between MCI and SCD, and above 0.85 between ADD and MCI. We can differentiate between adjacent phases of the AD spectrum with blood biomarkers and brain MR images with the help of machine learning algorithms.

Relevance of plasma biomarkers to pathologies in Alzheimer's disease, Parkinson's disease and frontotemporal dementia

Amyloid plaques and tau tangles are pathological hallmarks of Alzheimer's disease (AD). Parkinson's disease (PD) results from the accumulation of α-synuclein. TAR DNA-binding protein (TDP-43) and total tau protein (T-Tau) play roles in FTD pathology. All of the pathological evidence was found in the biopsy. However, it is impossible to perform stein examinations in clinical practice. Assays of biomarkers in plasma would be convenient. It would be better to investigate the combinations of various biomarkers in AD, PD and FTD. Ninety-one subjects without neurodegenerative diseases, 76 patients with amnesic mild cognitive impairment (aMCI) or AD dementia, combined as AD family, were enrolled. One hundred and nine PD patients with normal cognition (PD-NC) or dementia (PDD), combined as PD family, were enrolled. Twenty-five FTD patients were enrolled for assays of plasma amyloid β 1-40 (Aβ_1-40), Aβ_1-42, T-Tau, α-synuclein and TDP-43 using immunomagnetic reduction (IMR). The results show that Aβs and T-Tau are major domains in AD family. α-synuclein is highly dominant in PD family. FTD is closely associated with TDP-43 and T-Tau. The dominant plasma biomarkers in AD family, PD family and FTD are consistent with pathology. This implies that plasma biomarkers are promising for precise and differential assessments of AD, PD and FTD in clinical practice.

Distinct brain lipid signatures in response to low-level PM2.5 exposure in a 3xTg-Alzheimer's disease mouse inhalation model

Fine particulate matter (PM_2.5) poses a significant risk to human health. The molecular mechanisms underlying low-level PM_2.5-induced neurotoxicity in the central nervous system remain unclear. In addition, changes in lipids in response to PM_2.5 exposure have not yet been fully elucidated. In this study, 3xTg-Alzheimer's disease (AD) mice experienced continuous whole-body exposure to non-concentrated PM_2.5 for three consecutive months, while control mice inhaled particulate matter-filtered air over the same time span. A liquid chromatography-mass spectrometry-based lipidomic platform was used to determine the distinct lipid profiles of various brain regions. The average PM_2.5 concentration during the exposure was 11.38 μg/m³, which was close to the regulation limits of USA and Taiwan. The partial least squares discriminant analysis model showed distinct lipid profiles in the cortex, hippocampus, and olfactory bulb, but not the cerebellum, of mice in the exposure group. Increased levels of fatty acyls, glycerolipids, and sterol lipids, as well as the decreased levels of glycerophospholipids and sphingolipids in PM_2.5-exposed mouse brains may be responsible for the increased energy demand, membrane conformation, neuronal loss, antioxidation, myelin function, and cellular signaling pathways associated with AD development. Our research suggests that subchronic exposure to low levels of PM_2.5 may cause neurotoxicity by changing the lipid profiles in a susceptible model. Lipidomics is a powerful tool to study the early effects of PM_2.5-induced AD toxicity.

White matter pathology in alzheimer's transgenic mice with chronic exposure to low-level ambient fine particulate matter

Background

Air pollution, especially fine particulate matter (PM), can cause brain damage, cognitive decline, and an increased risk of neurodegenerative disease, especially alzheimer’s disease (AD). Typical pathological findings of amyloid and tau protein accumulation have been detected in the brain after exposure in animal studies. However, these observations were based on high levels of PM exposure, which were far from the WHO guidelines and those present in our environment. In addition, white matter involvement by air pollution has been less reported. Thus, this experiment was designed to simulate the true human world and to discuss the possible white matter pathology caused by air pollution.

Results

6 month-old female 3xTg-AD mice were divided into exposure and control groups and housed in the Taipei Air Pollutant Exposure System (TAPES) for 5 months. The mice were subjected to the Morris water maze test after exposure and were then sacrificed with brain dissection for further analyses. The mean mass concentration of PM_2.5 during the exposure period was 13.85 μg/m³. After exposure, there was no difference in spatial learning function between the two groups, but there was significant decay of memory in the exposure group. Significantly decreased total brain volume and more neuronal death in the cerebral and entorhinal cortex and demyelination of the corpus callosum were noted by histopathological staining after exposure. However, there was no difference in the accumulation of amyloid or tau on immunohistochemistry staining. For the protein analysis, amyloid was detected at significantly higher levels in the cerebral cortex, with lower expression of myelin basic protein in the white matter. A diffuse tensor image study also revealed insults in multiple white matter tracts, including the optic tract.

Conclusions

In conclusion, this pilot study showed that even chronic exposure to low PM_2.5 concentrations still caused brain damage, such as gross brain atrophy, cortical neuron damage, and multiple white matter tract damage. Typical amyloid cascade pathology did not appear prominently in the vulnerable brain region after exposure. These findings imply that multiple pathogenic pathways induce brain injury by air pollution, and the optic nerve may be another direct invasion route in addition to olfactory nerve.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00485-8.

Assessment of High Risk for Alzheimer's Disease Using Plasma Biomarkers in Subjects with Normal Cognition in Taiwan: A Preliminary Study

Background

In Alzheimer's disease (AD), cognitive impairment begins 10-15 years later than neurodegeneration in the brain. Plasma biomarkers are promising candidates for assessing neurodegeneration in people with normal cognition. It has been reported that subjects with the concentration of plasma amyloid-β 1-42×total tau protein higher than 455 pg²/ml² are assessed as having a high risk of amnesic mild impairment or AD, denoted as high risk of AD (HRAD).

Objective

The prevalence of high-risk for dementia in cognitively normal controls is explored by assaying plasma biomarkers.

Methods

422 subjects with normal cognition were enrolled around Taiwan. Plasma Aβ_1-40, Aβ_1-42, and T-Tau levels were assayed using immunomagnetic reduction to assess the risk of dementia.

Results

The results showed that 4.6% of young adults (age: 20-44 years), 8.5% of middle-aged adults (age: 45-64 years), and 7.3% of elderly adults (age: 65-90 years) had HRAD. The percentage of individuals with HRAD dramatically increased in middle-aged and elderly adults compared to young adults.

Conclusion

The percentage of HRAD in cognitively normal subjects are approximately 10%, which reveals that the potentially public-health problem of AD in normal population. Although the subject having abnormal levels of Aβ or tau is not definitely going on to develop cognitive declines or AD, the risk of suffering cognitive impairment in future is relatively high. Suitable managements are suggested for these high-risk cognitively normal population. Worth noting, attention should be paid to preventing cognitive impairment due to AD, not only in elderly adults but also middle-aged adults.

Investigation of the Number of Tests Required for Assaying Plasma Biomarkers Associated with Alzheimer's Disease Using Immunomagnetic Reduction

INTRODUCTION

Concentrations of plasma biomarkers associated with Alzheimer's disease have been reported to be as low as several tens of picograms/milliliter (pg/ml). However, in assays measuring these biomarkers, it is likely that repeated measurements are necessary to obtain reliable values.

METHODS

We performed assays as a single test or as duplicate, quadruplicate, fivefold and tenfold repeated tests, on samples spiked with different concentrations of amyloid β 1-40 (Aβ_1-40; 1-1000 pg/ml), Aβ_1-42 (1-30,000 pg/ml) and total Tau protein (T-Tau; 0.1-1000 pg/ml), with the aim to to calculate the coefficients of variation (CVs).

RESULTS

The results demonstrated common changes in the CVs with changes in the number of tests for a given sample: the CVs decreased with increases in the number of tests from one to ten. All CV values were distributed within the range of 0.35 to 15.5%; as such, the CV values were all lower than the acceptable value of 20%.

CONCLUSION

Based on this study, a single assay of Aβ_1-40, Aβ_1-42 and T-Tau, respectively, provides reliable results in terms of the measurement of that plasma biomarker.

An Exploration of the Own-Age Effect on Facial Emotion Recognition in Normal Elderly People and Individuals with the Preclinical and Demented Alzheimer's Disease

BACKGROUND

The issue of whether there exists an own-effect on facial recognition in the elderly remains equivocal. Moreover, currently the literature of this issue in pathological aging is little.

OBJECTIVE

Our study was thus to explore the issue in both of healthy older people and patients with ADMethods:In study 1, 27 older and 31 younger healthy adults were recruited; in study 2, 27 healthy older adults and 80 patients (including subjective cognitive decline (SCD), mild cognitive impairment (MCI), and Alzheimer's disease (AD) groups) were recruited. Participants received the Taiwan Facial Emotion Recognition Task (FER Task), and a clinical neuropsychological assessment.

RESULTS

No significant differences on the FER test were found among our groups, except for sadness recognition in which our MCI and AD patients' scores were remarkably lower than their healthy counterparts. The own-age effect was not significantly evident in healthy younger and older adults, except for recognizing neutral photos. Our patients with MCI and AD tended to have the effect, particularly for the sad recognition in which the effect was significantly evident in terms of error features (mislabeling it as anger in younger-face and neutral in older-face photos).

CONCLUSION

Our results displayed no remarkable own-age effect on facial emotional recognition in the healthy elderly (including SCD). However, it did not appear the case for MCI and AD patients, especially their recognizing those sadness items, suggesting that an inclusion of the FER task particularly involving those items of low-intensity emotion in clinical neuropsychological assessment might be contributory to the early detection of AD-related pathological individuals.

Prognostic Features of Sporadic Creutzfeldt-Jakob Disease: An Analysis of Taiwan's Nationwide Surveillance

OBJECTIVES

To study the prognostic features of Creutzfeldt-Jakob disease (CJD) and shed light on its future therapy.

DESIGN

Retrospective cohort study of a longitudinal national cohort of the Taiwan Centers for Disease Control.

SETTING AND PARTICIPANTS

All patients with suspected CJD are reported to the CJD surveillance unit of the Taiwan Centers for Disease Control. An expert committee discussed the reported cases and designated a consensus-based diagnosis. From 1996 to 2020, a total of 809 cases were referred to the CJD surveillance unit for confirmation; of these, 441 cases (women, n = 230) were determined to be sporadic CJD.

METHODS

We investigated the clinical manifestations and laboratory findings for 400 patients diagnosed with definite or probable sporadic CJD. We used Kaplan-Meier analyses and Cox proportional hazards model to identify prognostic factors.

RESULTS

The mean age of onset was 67 ± 9.9 years. The mean survival duration was 13.3 ± 14.2 (median 10) months. The leading clinical symptoms were myoclonus (73%) and akinetic mutism (54%). For PRNP polymorphism, 99% of patients (195/197) showed a methionine homozygous genotype at codon 129 (M129M). The sensitivity of periodic sharp wave complexes (PSWCs) on electroencephalograms (EEGs) was 59.7%. The sensitivity of cerebrospinal fluid 14-3-3 protein and total tau protein (>1200 pg/mL) were 69.7% and 75.6%, respectively. Younger patients lived longer than those aged ≥65 years [hazard ratio (HR) 0.466, P < .001]. Women had a better survival probability in the first 3 years than their male counterparts (HR 0.712, P = .005). PSWCs had a persistent negative effect on survival (HR 0.788, P < .05). Although uncommon, epileptic seizures were the only clinical prognostic factor for survival time (HR 0.768, P < .05). PSWCs can be used as an EEG biomarker for prognosis. Epileptic seizures, though not common, are the only clinical prognostic factor for a short survival.

CONCLUSIONS AND IMPLICATIONS

We found that a lower age of onset and female gender favor the survival of patients with sCJD. PSWCs are EEG biomarkers unfavorable for survival, and so are epileptic seizures.

Synergistic Association between Plasma Aβ1-42 and p-tau in Alzheimer's Disease but Not in Parkinson's Disease or Frontotemporal Dementia

Beta-amyloid (Aβ_1–42) triggers the phosphorylation of tau protein in Alzheimer’s disease (AD), but the relationship between phosphorylated tau (p-tau) and Aβ_1–42 in the blood is not elucidated. We investigated the association in individuals with AD (n = 62, including amnesic mild cognitive impairment and dementia), Parkinson’s disease (n = 30), frontotemporal dementia (n = 25), and cognitively unimpaired controls (n = 41) using immunomagnetic reduction assays to measure plasma Aβ_1–42 and p-tau181 concentrations. Correlation and regression analyses were performed to examine the relation between plasma levels, demographic factors, and clinical severity. Both plasma Aβ_1–42 and p-tau concentrations were significantly higher in AD and frontotemporal dementia than in the controls and Parkinson’s disease. A significant positive association was found between plasma p-tau and Aβ_1–42 in controls (r = 0.579, P < 0.001) and AD (r = 0.699, P < 0.001) but not in frontotemporal dementia or Parkinson’s disease. Plasma p-tau was significantly associated with clinical severity in the AD in terms of scores of clinical dementia rating (r = 0.288, P = 0.025) and mini-mental state examination (r = −0.253, P = 0.049). Regression analysis showed that plasma Aβ_1–42 levels explain approximately 47.7% of the plasma p-tau levels in the AD after controlling age, gender, and clinical severity. While in non-AD participants, the clinical dementia rating explained about 47.5% of the plasma p-tau levels. The disease-specific association between plasma Aβ_1–42 and p-tau levels in AD implies a possible synergic effect in mechanisms involving these two pathological proteins’ genesis.

Rural-urban disparities in the prevalence of mild cognitive impairment and dementia in Taiwan: A door-to-door nationwide study

BACKGROUND

Screening or diagnosis for the elderly with dementia in rural regions might be delayed and underestimated due to limited utilization of healthcare resources. This study aimed to evaluate the disparities of prevalence and risk factors of mild cognitive impairment (MCI) and dementia between urban and rural residence.

METHODS

In this nationwide door-to-door survey, 10,432 participants aged 65 years and more were selected by computerized random sampling from all administrative districts in Taiwan and were assessed by an in-person interview. We calculated the prevalence of MCI and dementia with their risk factors examined by multivariable logistic regression.

RESULTS

The prevalence of dementia in rural, suburban, and urban areas among the elderly was 8.69% (95% CI, 8.68-8.69), 6.63% (95% CI, 6.62-6.63), and 4.46% (95% CI, 4.46-4.47), respectively. A similar rural-suburban-urban gradient relationship on the dementia prevalence was observed in any age and sex group. The rural/urban ratio was higher in women than in men for both MCI and dementia. Urbanization remained to be an independent factor for both MCI and dementia after adjustment for age, gender, education, lifestyle, and health status. The beneficial effects of exercise on dementia were more evident in rural areas than in urban ones.

CONCLUSIONS

Significantly higher prevalence of MCI and dementia were found in rural areas than in urban ones, especially for women. The odds of risk factors for MCI and dementia varied between urbanization statuses. Focus on the rural-urban inequality and the modification of associated factors specifically for different urbanization levels are needed.

Integrated 18F-T807 Tau PET, Structural MRI, and Plasma Tau in Tauopathy Neurodegenerative Disorders

Background and Objective: Tau-specific positron emission topography (PET) imaging enables in vivo assessment of Alzheimer's disease (AD). We aimed to investigate its performance in combination with plasma tau levels in patients with non-AD tauopathy.

Methods: A total of 47 participants were enrolled, including 10 healthy controls, 16 with tauopathy parkinsonism syndromes (9 with corticobasal syndrome [CBS], 7 with progressive supranuclear palsy [PSP]), 9 with frontotemporal dementia (FTD), 4 with AD, and 8 with Parkinson's disease (PD). All participants underwent clinical assessments, ¹⁸F-T807 tau PET, brain MRI, and plasma tau assay.

Results: The global cortical standard uptake value ratio (SUVR) of ¹⁸F-T807 PET was comparable between PD and control (p = 0.088). The cortical SUVR was significantly higher in AD group (p = 0.002) but was modestly increased in PSP group compared to the PD group (p = 0.044), especially in parietal and pallidal regions. Asymmetric ¹⁸F-T807 uptake at the pallidum was noted in patients with CBS and FTD. Cortical tau tracer uptake was associated with increased plasma total tau level (p = 0.016), especially in frontal and parietal regions. Regional tracer uptake was correlated with cortical thinning in patients with CBS and PSP (CBS: r = −0.092, p = 0.025; PSP: r = −0.114, p = 0.015).

Conclusions: The ¹⁸F-T807 tau tracer uptake was only modestly increased in patients with PSP. Although the cortical tau tracer uptake correlated with regional cortical atrophy and plasma tau levels, a four-repeated tau-specific tracer is needed for future classifying tauopathy parkinsonism syndromes.

Incidence of and Mortality Due to Human Prion Diseases in Taiwan: A Prospective 20-Year Nationwide Surveillance Study from 1998 to 2017

Introduction

Epidemiologic studies of Creutzfeldt-Jakob disease (CJD) have been undertaken worldwide since the new variant CJD outbreak in 1996 in the United Kingdom. A nationwide report system, the Creutzfeldt-Jakob Disease Surveillance Unit (CJDSU), directed by the Centers for Disease Control of Taiwan, was established in 1997 to identify human prion diseases.

Methods

From 1998 to 2017, 647 cases were referred to the committee for confirmation. The report to CJDSU included a structured questionnaire recording the clinical, demographic data, and potential iatrogenic exposure, and the results of the clinical and laboratory examination, including tests of blood and cerebrospinal fluid, electroencephalography, and brain magnetic resonance imaging.

Results

In total, 356 cases (women, n=178) were ascertained to be human prion diseases, and 97.4% (n=347) were sporadic CJD, including three definite, 314 probable, and 30 possible cases; one probable variant CJD and 8 cases of the genetic form human prion diseases. The age- and gender-specific average annual incidence were also significantly higher in the second decade (0.95/1,000,000) than in the first decade (0.63/1,000,000), with an incidence rate ratio of 1.51. The incidences increased with increasing age, reaching a peak at the age of 70-79 years. The 10-year survival curve for sCJD patients showed that the 1-, 5-, and 10-year cumulative survival rate were 52%, 5%, and 1%, respectively. PRNP polymorphisms in 170 patients showed that 98.8% were M129M and 97.6% E219E.

Discussion

The significant increase in incidence after 2008 suggests the increase in the awareness of this rare disease among physicians. The longer disease duration in patients with sCJD in Taiwan than in other countries indicates that the comprehensive support of the health care system, as well as the end-of-life care culture in Taiwan, may prolong survival time in patients with such a progressive and fatal disease.

Classifications of Neurodegenerative Disorders Using a Multiplex Blood Biomarkers-Based Machine Learning Model

Easily accessible biomarkers for Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal dementia (FTD), and related neurodegenerative disorders are urgently needed in an aging society to assist early-stage diagnoses. In this study, we aimed to develop machine learning algorithms using the multiplex blood-based biomarkers to identify patients with different neurodegenerative diseases. Plasma samples (n = 377) were obtained from healthy controls, patients with AD spectrum (including mild cognitive impairment (MCI)), PD spectrum with variable cognitive severity (including PD with dementia (PDD)), and FTD. We measured plasma levels of amyloid-beta 42 (Aβ42), Aβ40, total Tau, p-Tau181, and α-synuclein using an immunomagnetic reduction-based immunoassay. We observed increased levels of all biomarkers except Aβ40 in the AD group when compared to the MCI and controls. The plasma α-synuclein levels increased in PDD when compared to PD with normal cognition. We applied machine learning-based frameworks, including a linear discriminant analysis (LDA), for feature extraction and several classifiers, using features from these blood-based biomarkers to classify these neurodegenerative disorders. We found that the random forest (RF) was the best classifier to separate different dementia syndromes. Using RF, the established LDA model had an average accuracy of 76% when classifying AD, PD spectrum, and FTD. Moreover, we found 83% and 63% accuracies when differentiating the individual disease severity of subgroups in the AD and PD spectrum, respectively. The developed LDA model with the RF classifier can assist clinicians in distinguishing variable neurodegenerative disorders.

The contribution of vascular risk factors in neurodegenerative disorders: from mild cognitive impairment to Alzheimer's disease

Background

Optimization of vascular risk factor control is emerging as an alternative approach to improve cognitive outcomes in Alzheimer’s disease, although its efficacy is still under debate. We aimed to investigate the contribution of vascular risk factors on Alzheimer’s biomarkers and conversion rate to dementia in subjects with mild cognitive impairment (MCI) with low cerebral small vessel disease burden.

Methods

Two hundred ninety-five newly diagnosed MCI subjects were enrolled from March 2005 to May 2017 for a cross-sectional assessment of vascular risk factors and Alzheimer’s plasma and imaging biomarkers, followed by a cognitive outcome assessment 24 months after enrollment. The association between vascular risk factors and Alzheimer’s biomarkers were tested using multivariable linear regression models adjusted with age, gender, education, and APOE ε4 allele. The association between vascular risk factors and conversion to dementia was tested using multivariable logistic regression models adjusted with age, gender, education, and baseline Mini-Mental State Examination (MMSE) score.

Results

At baseline, higher low-density lipoprotein (LDL) cholesterol level was associated with more advanced plasma biomarkers, including Aβ42/Aβ40 ratio (P = 0.012) and tau level (P = 0.001). A history of hypertension was associated with more advanced white matter hyperintensity (P = 0.011), while statin therapy for dyslipidemia was associated with less advanced white matter hyperintensity (P = 0.002). At 24 months, individual vascular risk factor was not significantly associated with cognitive outcome. By contrast, statin therapy for dyslipidemia was associated with reduced conversion to dementia (adjusted OR = 0.191, 95% CI = 0.062~0.586, P = 0.004).

Conclusions

For MCI subjects, dyslipidemia may contribute to AD-related neurodegeneration while hypertension may contribute to vascular pathology. The association between statin therapy for dyslipidemia and reduced conversion to dementia supports further interventional study to evaluate the potential beneficial effect of statin in MCI subjects.

Development of an assay of plasma neurofilament light chain utilizing immunomagnetic reduction technology

Axonal damage leads to the release of neurofilament light chain (NFL), which enters the CSF or blood. In this work, an assay kit for plasma NFL utilizing immunomagnetic reduction (IMR) was developed. Antibodies against NFL were immobilized on magnetic nanoparticles to develop an IMR NFL kit. The preclinical properties, such as the standard curve, limit of detection (LoD), and dynamic range, were characterized. Thirty-one normal controls (NC), fifty-two patients with Parkinson's disease (PD) or PD dementia (PDD) and thirty-one patients with Alzheimer's disease (AD) were enrolled in the study evaluating the plasma NFL assay using an IMR kit. T-tests and receiver operating characteristic (ROC) curve analysis were performed to investigate the capability for discrimination among the clinical groups according to plasma NFL levels. The LoD of the NFL assay using the IMR kit was found to be 0.18 fg/ml. The dynamic range of the NFL assay reached 1000 pg/ml. The NC group showed a plasma NFL level of 7.70 ± 4.00 pg/ml, which is significantly lower than that of the PD/PDD (15.85 ± 7.82 pg/ml, p < 0.001) and AD (19.24 ± 8.99 pg/ml, p < 0.001) groups. A significant difference in plasma NFL levels was determined between the PD and AD groups (p < 0.01). Through ROC curve analysis, the cut-off value of the plasma NFL concentration for differentiating NCs from dementia patients (AD and PD/PDD) was found to be 12.71 pg/ml, with a clinical sensitivity and specificity of 73.5% and 90.3%, respectively. The AUC was 0.868. Furthermore, the cut-off value of the plasma NFL concentration for discriminating AD from PD/PDD was found to be 18.02 pg/ml, with a clinical sensitivity and specificity of 61.3% and 65.4%, respectively. The AUC was 0.630. An ultrasensitive assay for measuring plasma NFL utilizing IMR technology was developed. Clear differences in plasma NFL concentrations were observed among NCs and PD and AD patients. These results imply that the determination of plasma NFL is promising not only for screening dementia but also for differential diagnosis.

Stability of Plasma Amyloid-β 1-40, Amyloid-β 1-42, and Total Tau Protein over Repeated Freeze/Thaw Cycles

Introduction

Blood biomarkers of Alzheimer's disease (AD) have attracted much attention of researchers in recent years. In clinical studies, repeated freeze/thaw cycles often occur and may influence the stability of biomarkers. This study aims to investigate the stability of amyloid-β 1–40 (Aβ_1–40), amyloid-β 1–42 (Aβ_1–42), and total tau protein (T-tau) in plasma over freeze/thaw cycles.

Methods

Plasma samples from healthy controls (n = 2), AD patients (AD, n =3) and Parkinson's disease patients (PD, n = 3) were collected by standardized procedure and immediately frozen at −80°C. Samples underwent 5 freeze/thaw (−80°C/room temperature) cycles. The concentrations of Aβ_1–40, Aβ_1–42, and T-tau were monitored during the freeze/thaw tests using an immunomagnetic reduction (IMR) assay. The relative percentage of concentrations after every freeze/thaw cycle was calculated for each biomarker.

Results

A tendency of decrease in the averaged relative percentages over samples through the freeze and thaw cycles for Aβ_1–40 (100 to 97.11%), Aβ_1–42 (100 to 94.99%), and T-tau (100 to 95.65%) was found. However, the decreases were less than 6%. For all three biomarkers, no statistical significance was found between the levels of fresh plasma and those of the plasma experiencing 5 freeze/thaw cycles (p > 0.1).

Conclusions

Plasma Aβ_1–40, Aβ_1–42, and T-tau are stable through 5 freeze/thaw cycles measured with IMR.

Nanoparticle-based immunomagnetic assay of plasma biomarkers for differentiating dementia and prodromal states of Alzheimer's disease - A cross-validation study

Blood-based biomarker assays of plasma β-amyloid (Aβ) and tau have the advantages of cost-effective and less invasive for the diagnosis of Alzheimer's disease (AD). We used two independent cohorts to cross-validate the clinical use of the nanoparticle-based immunomagnetic assay of plasma biomarkers to assist in the differential diagnosis of early AD. There were in total 160 subjects in the derivation cohort, and 242 in the validation cohort both containing controls, mild cognitive impairment due to AD and AD dementia diagnosed according to the 2011 NIA-AA guidelines. The cutoff value for plasma Aβ_1-42 (16.4 pg/ml) performed the best in differentiating between controls and patients with prodromal or clinical AD, with 92.5% for positive percent agreement (PPA), negative percent agreement (NPA), and overall rate of agreement (ORA). Aβ_1-42 × tau (642.58) was useful for separating patients with dementia and prodromal states of AD, with 84.9% PPA, 78.8% NPA and 83% ORA.

Predictors and associating factors of nasogastric tube removal: Clinical and brain imaging data analysis in post-stroke dysphagia

BACKGROUND/PURPOSE

Post-stroke dysphagia is a frequent complication. Although most patients with dysphagia recover after the acute phase, some patients require long-term enteral feeding, either through a nasogastric (NG) or gastrostomy tube; the effectiveness of using either tube is still under debate. This study elucidated the natural course of NG tube installation and removal and examined the predictors and associating factors based on clinical and brain imaging data.

METHODS

This retrospective cohort study with medical record reviews recruited patients received NG tube installation after their acute stroke events between January 1, 2016, and December 31, 2016. Inclusion criteria were subjects above 20 years of age and with a diagnosis of a newly onset stroke except SAH whose comprehensive clinical and imaging data were available. Survival analysis was performed for the right-censored data because some patients were lost to follow-up after discharge or transferal.

RESULTS

In total we recruited 135 patients. Among these patients, the timing of their NG tube removal reached a plateau at 12-16 weeks after stroke. The modified Rankin score on discharge, representing the overall subacute disease status, was the most significant factor. Other clinical variables could be divided into 2 categories: baseline patient characteristics and stroke event severity. Moreover, semi-quantitative brain imaging scores corresponding to the aforementioned 3 categories were correlated significantly.

CONCLUSION

In Taiwan, the NG tube removal rate reached a plateau at around 12-16 weeks after stroke onset. Variables related to long-term NG tube use were divided into baseline characteristics of patient and stroke event severity.