Journal of Alzheimer's Disease - Volume 70, issue 4

Authors: Mendes, Tiago | Cardoso, Sandra | Guerreiro, Manuela | Maroco, João | Silva, Dina | Alves, Luísa | Schmand, Ben | Gerardo, Bianca | Lima, Marisa | Santana, Isabel | de Mendonça, Alexandre

Article Type: Research Article

Abstract: Background: The use of biomarkers, in particular amyloid-β (Aβ) changes, has allowed the possibility to identify patients with subjective memory complaints (SMCs) and amnestic mild cognitive impairment (aMCI) who suffer from Alzheimer’s disease (AD). Since it is unfeasible that all patients with aMCI could presently undergo biomarkers assessment, it would be important that SMCs might contribute to identify the aMCI patients who have AD amyloid pathology. Objectives: To know whether aMCI patients with amyloid biomarkers (Aβ+ ) present greater SMCs as compared to those without amyloid biomarkers (Aβ- ). Methods: Participants were selected from a cohort …of nondemented patients with cognitive complaints and a comprehensive neuropsychological evaluation, on the basis of 1) diagnosis of aMCI; 2) detailed assessment of memory difficulties with the SMC Scale; and 3) known amyloid status. The amyloid status was determined on the basis of either CSF Aβ1–42 concentration or amyloid PET imaging. Results: Of the 176 patients with aMCI studied, 90 were Aβ+ and 86 were Aβ- . The two groups did not differ in terms of age, gender, and education. The SMC total score was not significantly different in the Aβ+ aMCI patients (9.48±4.18) when compared to the Aβ- aMCI patients (10.52±4.57). The Aβ+ aMCI patients had lower scores on the MMSE and memory/learning tests, but not on the Geriatric Depression Scale, when comparing to the Aβ- aMCI patients. Conclusions: Evaluating SMCs does not seem helpful to identify, among patients with aMCI, those who have AD. Show more

Keywords: Alzheimer’s disease, amnestic, amyloid-β, anosognosia, depressive symptoms, mild cognitive impairment, subjective memory complaints

DOI: 10.3233/JAD-190414

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1103-1111, 2019

Authors: Pérez-Ros, Pilar | Martínez-Arnau, Francisco Miguel | Baixauli-Alacreu, Susana | Caballero-Pérez, Mireia | García-Gollarte, José Fermín | Tarazona-Santabalbina, Francisco

Article Type: Research Article

Abstract: Background: Delirium is a common geriatric syndrome, with a prevalence of between 15–70% among older long-term care residents. It is associated with adverse outcomes, and its onset may prove imperceptible to health professionals. Few studies in institutionalized older people have analyzed the predictors of delirium. Objective: The aim of the present study was to identify delirium predisposing and triggering factors, and develop a predictive model. Methods: A cohort trial-nested case-control study covering a period of 12 consecutive months (April 2015 – March 2016) was carried out. Predisposing and triggering episodes of delirium were recorded. …Results: A total of 443 older persons were recruited, with a mean age of 85.73 (6.72) years and female predominance (78.3%; n  = 374). The incidence of older people with delirium was 18.7% (n  = 83). Dementia was the predisposing factor with the highest predictive capacity (OR = 2.74 [1.49–5.04]). In the presence of dementia, falls (OR = 2.45 [1.49–3.69]), neuroleptics (OR = 2.39 [1.23–4.65]) and anticholinergic drug use (OR = 1.87 [0.95–3.69]) were identified as triggering factors. The area under the curve (AUC) was 0.72 (95% CI: 0.66–0.78). Conclusions: Our findings suggest that interventions targeted to potentially preventable triggering factors could avoid the onset of delirium in older people with dementia. Knowledge of the predictive factors of delirium facilitates the screening of older people at increased risk, thereby allowing mental health service providers to prevent and identify the onset of a delirium episode. The decrease in delirium predictive factors should lead to a direct reduction in the occurrence of delirium and its consequences. Show more

Keywords: Aged, delirium, incidence, nursing home, risk factors

DOI: 10.3233/JAD-190391

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1113-1122, 2019

Authors: Suh, Seung Wan | Han, Ji Won | Lee, Ju Ri | Byun, Seonjeong | Kwak, Kyung Phil | Kim, Bong Jo | Kim, Shin Gyeom | Kim, Jeong Lan | Kim, Tae Hui | Ryu, Seung-Ho | Moon, Seok Woo | Park, Joon Hyuk | Seo, Jiyeong | Youn, Jong Chul | Lee, Dong Young | Lee, Dong Woo | Lee, Seok Bum | Lee, Jung Jae | Jhoo, Jin Hyeong | Yoon, In Young | Kim, Ki Woong

Article Type: Research Article

Abstract: Prospective studies concerning sleep architecture and cognitive function have focused on individual sleep measures per se , without considering the complementary role of non-REM (NREM) and REM sleep. We explored the association between NREM/REM cycle-related sleep architecture and cognitive decline. Community-dwelling elderly people in Korea from the Korean Longitudinal Study on Cognitive Aging and Dementia were enrolled. They were cognitively normal and underwent overnight polysomnography at baseline. A NREM/REM cycle is a sequence of NREM and REM sleep, uninterrupted by a waking period of >2 min. After 4 years, the development of mild cognitive impairment (MCI) or dementia was related to …the measures of sleep architecture, including NREM/REM cycle parameters by logistic regression analyses. Of 235 participants (mean [SD] age 68 [5] years; 60% female) at baseline, 14 (5.9%) developed MCI/dementia at follow-up. A short average cycle length (OR, 0.97 [95% CI, 0.94–0.99]; p  = 0.02) was significantly associated with cognitive decline. When its substructure and NREM and REM sleep outside of cycles were considered simultaneously, the average REM sleep duration per cycle (OR, 0.87 [95% CI, 0.76–0.98]; p  = 0.03) was significantly related to the outcome. In conclusion, short average duration of NREM/REM cycles, especially average REM sleep duration in each cycle, in cognitively normal elderly might be used as an early marker of cognitive decline. Show more

Keywords: Dementia, mild cognitive impairment, sequential hypothesis, sleep

DOI: 10.3233/JAD-190399

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1123-1132, 2019

Authors: Lv, Xin | Zhou, Dongtao | Ge, Baojin | Chen, Hui | Du, Yue | Liu, Shuai | Ji, Yong | Sun, Changqing | Wang, Guangshun | Gao, Yuxia | Li, Wen | Huang, Guowei

Article Type: Research Article

Abstract: Background: The nutrition state plays an important role in the progress of aging. Folate may play a role in protecting mitochondrial (mt) DNA by reducing oxidative stress. Objective: The primary aim of this study was to examine the association of mitochondrial oxidative damage with risk of Alzheimer’s disease (AD), and to explore the possible role of folate metabolites in this association in a matched case-control study. Methods: Serum folate metabolites and mitochondrial function in peripheral blood cells were determined in 82 AD cases and 82 healthy controls, individually matched by age, gender, and education. …Results: AD patients had lower serum levels of folate and higher homocysteine (Hcy) concentration. AD patients had a reduced mtDNA copy number, higher mtDNA deletions, and increased 8-OHdG content in mtDNA indicative of reduced mitochondrial function. The highest level of mtDNA copy number would decrease the risk of AD (OR  = 0.157, 95% CI : 0.058–0.422) compared to the lowest level, independently of serum folate, and Hcy levels. Serum folate levels correlated with low 8-OHdG content in mtDNA both in AD patients and controls, independently of serum Hcy level. Moreover, serum Hcy levels correlated with low copy number in mtDNA both in AD patients and controls, independently of serum folate levels. Conclusion: In conclusion, mitochondrial function in peripheral blood cells could be associated with risk of AD independent of multiple covariates. AD patients with a folate deficiency or hyperhomocysteinemia had low mitochondrial function in peripheral blood cells. However, further randomized controlled trials are need to determine a causal effect. Show more

Keywords: Alzheimer’s disease, China, folate metabolites, mitochondrial function, peripheral blood cells

DOI: 10.3233/JAD-190477

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1133-1142, 2019

Authors: Menzel, Leoni C. | Kramer, Philipp W. | Groneberg, David A. | Bendels, Michael H.K.

Article Type: Research Article

Abstract: Background: Alzheimer’s disease and dementia are an increasing burden affecting more than 50 million patients worldwide. Hence, research has increased significantly in recent decades. It is recognized that female authors are systematically underrepresented in research in general. Objective: In this article, we examine gender disparities in academic research on dementia and Alzheimer’s disease in the last decade. Methods: 104,858 male and female authorships from 37,961 original research articles were analyzed. The global and country-specific distribution of women across first, co, and last authorships was determined with the inclusion of a citation and productivity analysis. …Results: 42.1% of all authorships and 50.2% of the first, 42.2% of the co, and 32.8% of the last authorships were held by women. Women were less commonly cited, published fewer articles and were also less likely to secure prestigious authorships in articles with multiple authors compared with men. Distinct differences were observed among the countries. Conclusion: Substantial growth in the number of prestigious female authorships has been observed to date and is predicted to continue in the future, with an emphasis on the progressive representation of women and a diminishing gender gap. Show more

Keywords: Citation, gender gap, odds ratio, Prestige Index, productivity

DOI: 10.3233/JAD-190216

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1143-1152, 2019

Authors: Huang, Chuanying | Sun, Shuqin | Wang, Weijing | Li, Yujie | Feng, Wenjing | Wu, Yili

Article Type: Research Article

Abstract: Background/Objective: Gait speed is an important indicator for assessing overall health status. Previous studies have reported the important role of sensory function in gait speed; however, the underlying mechanism is still unclear. This study aimed to examine whether cognition mediates the association of sensory function with gait speed among English older adults. Methods: Gait speed was assessed by “timed walking test”. Hearing was measured by using a hearing screening device. Vision was self-reported. Cognition was assessed by questionnaire. Baron and Kenny’s causal steps method and Sobel test were used to examine the mediating effect. Results: Among …4,197 participants aged 60 years and older, 13.5% had poor hearing and 12.6% had poor vision, 2.6% had both poor hearing and poor vision. Multiple linear regression models suggested that poor hearing (β= – 1.905, p  < 0.001), poor vision (β= – 1.309, p  = 0.004), and poor dual sensory function (β= – 2.442, p  = 0.013) was associated with worse cognition. Cognition was correlated with gait speed (β= 0.004, p  < 0.001). Poor hearing (β= – 0.072, p  < 0.001), poor vision (β= – 0.031, p  = 0.029), and poor dual sensory function (β= – 0.081, p  = 0.011) was associated with slower gait speed. After introducing cognition into the models, regression coefficients between sensory function and gait speed decreased (β= – 0.066, p  < 0.001 for hearing; β= – 0.027, p  = 0.054 for vision; β= – 0.073, p  = 0.020 for combined hearing and vision). Sobel test identified the significant mediating effect of cognition on the association between sensory function and gait speed. Conclusion: Cognition partially mediates the association between sensory function and gait speed. Efforts to maintain mobility performance in older adults should consider protecting both sensory function and cognition. Show more

Keywords: Cognition, gait speed, hearing, mediating effect, vision

DOI: 10.3233/JAD-190364

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1153-1161, 2019

Authors: Guo, Zhiqiang | Ling, Zhenhua | Li, Yunxia

Article Type: Research Article

Abstract: Background: Recently, many studies have been carried out to detect Alzheimer’s disease (AD) from continuous speech by linguistic analysis and modeling. However, few of them utilize language models (LMs) to extract linguistic features and to investigate the lexical-level differences between AD and healthy speech. Objective: Our goals include obtaining state-of-art performance of automatic AD detection, emphasizing N -gram LMs as powerful tools for distinguishing AD patients’ narratives from those of healthy controls, and discovering the differences of lexical usages between AD patients and healthy people. Method: We utilize a subset of the DementiaBank corpus, including 242 …control samples from 99 control participants and 256 AD samples from 169 “PossibleAD” or “ProbableAD” participants. Baseline models are built through area under curve-based feature selection and using five machine learning algorithms for comparison. Perplexity features are extracted using LMs to build enhanced detection models. Finally, the differences of lexical usages between AD patients and healthy people are investigated by a proportion test based on unigram probabilities. Results: Our baseline model obtains a detection accuracy of 80.7%. This accuracy increases to 85.4% after integrating the perplexity features derived from LMs. Further investigations show that AD patients tend to use more general, less informative, and less accurate words to describe characters and actions than healthy controls. Conclusion: The perplexity features extracted by LMs can benefit the automatic AD detection from continuous speech. There exist lexical-level differences between AD and healthy speech that can be captured by statistical N -gram LMs. Show more

Keywords: Geriatric assessment, language, machine learning, statistical

DOI: 10.3233/JAD-190452

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1163-1174, 2019

Authors: Lin, Lin | Liu, Aiyi | Li, Hanqin | Feng, Jian | Yan, Zhen

Article Type: Research Article

Abstract: Emerging evidence suggests that epigenetic dysregulation of gene expression is one of the key molecular mechanisms of neurodegeneration and Alzheimer’s disease (AD). However, little is known about the role of epigenetic dysregulation on synaptic dysfunction in humans, because of the difficulties of obtaining live human neurons. Here we generated mature human cortical neurons differentiated from human embryonic stem cells, and exposed them to amyloid-β (Aβ). We found that the histone methyltransferase, EHMT1, which catalyzes histone lysine 9 dimethylation (H3K9me2, a mark for gene repression), was significantly elevated in Aβ-treated human stem cell-derived neurons. Aβ treatment led to a significant reduction …of AMPAR-mediated whole-cell current and excitatory postsynaptic current. Application of BIX01294, a selective inhibitor of EHMT1/2, restored AMPAR currents and glutamatergic synaptic transmission in Aβ-treated human cortical neurons. These results suggest that inhibition of the aberrant histone methylation is a novel approach to reverse Aβ-induced synaptic deficits in human neurons. Show more

Keywords: Alzheimer’s disease, AMPA receptor, amyloid-β, EHMT1, epigenetics, histone methylation, histone methyltransferase, human stem cell-derived neurons

DOI: 10.3233/JAD-190190

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1175-1185, 2019

Authors: McGrath, Ryan | Robinson-Lane, Sheria G. | Cook, Summer | Clark, Brian C. | Herrmann, Stephen | O’Connor, Melissa Lunsman | Hackney, Kyle J.

Article Type: Research Article

Abstract: Background: Measures of handgrip strength may show promise for detecting cognitive erosion during aging. Objective: To determine the associations between lower handgrip strength and poorer cognitive functioning for aging Americans. Methods: There were 13,828 participants aged at least 50 years from the 2006 wave of the Health and Retirement Study included and followed biennially for 8 years. Handgrip strength was assessed with a hand-held dynamometer and cognitive functioning was assessed with a modified version of the Mini-Mental State Examination. Participants aged <65 years with scores 7– 11 had a mild cognitive impairment, ≤6 had a severe …cognitive impairment, and ≤11 had any cognitive impairment. Respondents aged ≥65 years with scores 8– 10 had a mild cognitive impairment, ≤7 had a severe cognitive impairment, and ≤10 had any cognitive impairment. Separate covariate-adjusted multilevel logistic models examined the associations between lower handgrip strength and any or severe cognitive impairment. A multilevel ordered logit model analyzed the association between lower handgrip strength and poorer cognitive functioning. Results: Every 5-kg lower handgrip strength was associated with 1.10 (95% confidence interval (CI): 1.04, 1.15) and 1.18 (CI: 1.04, 1.32) greater odds for any and severe cognitive impairment, respectively. Similarly, every 5-kg lower handgrip strength was associated with 1.10 (CI: 1.05, 1.14) greater odds for poorer cognitive functioning. Conclusions: Measurement of handgrip strength is a simple, risk-stratifying method for helping healthcare providers determine poorer cognitive functioning. Interventions aiming to prevent or delay cognitive dysfunction should also implement measures of handgrip strength as an assessment tool for determining efficacy. Show more

Keywords: Alzheimer’s disease, cognition, dementia, frailty, geriatrics, muscle strength, muscle weakness

DOI: 10.3233/JAD-190042

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1187-1196, 2019

Authors: Khosravi, Mohsen | Peter, Jonah | Wintering, Nancy A. | Serruya, Mijail | Shamchi, Sara Pourhassan | Werner, Thomas J. | Alavi, Abass | Newberg, Andrew B.

Article Type: Research Article

Abstract: Background: 18 F-Fluorodeoxyglucose (18 F-FDG) positron emission tomography (PET) and 18 F-florbetapir PET are approved neuroimaging biomarkers for the Alzheimer’s disease (AD) and mild cognitive impairment (MCI). Objectives: This study aims to compare the efficacy of 18 F-FDG and 18 F-florbetapir PET at evaluating the cognitive performance of patients with AD, MCI, and normal controls (NC). Methods: 63 subjects (36 male/27 female, mean age = 68.3) including 19 AD, 23 MCI, and 21 NC underwent 18 F-FDG and 18 F-florbetapir PET imaging. A global quantification approach was applied on supra-tentorial, frontal, parieto-occipital, temporal, and cerebellar brain regions by …calculating the global SUVmean ratios (GSUVr) as the weighted average of all regional SUVmean. 18 F-FDG and 18 F-florbetapir GSUVr of each region were subsequently correlated with the Mini-Mental State Examination (MMSE). Results: Subjects were studied in five categories as NC, MCI patients, AD patients, MCI and AD patients grouped together (MCI/AD), and a group including all the subjects (NC/MCI/AD). Both 18 F-FDG and 18 F-florbetapir could successfully detect subjects with dementia (p  < 0.001). Studied in all regions and groups, the correlation analysis of 18 F-FDG GSUVr with MMSE scores was significant in more regions and groups compared to that of 18 F-florbetapir. We also demonstrated that the correlation of 18 F-FDG GSUVr with MMSE is stronger than that of 18 F-florbetapir in the supra-tentorial and temporal regions. Conclusions: This study reveals how 18 F-FDG-PET global quantification is a superior indicator of cognitive performance in AD and MCI patients compared to 18 F-florbetapir PET. Accordingly, we still recommend 18 F-FDG-PET over amyloid imaging in the evaluation for AD and MCI. Show more

Keywords: Alzheimer’s disease, amyloid-β protein, 18F-FDG, florbetapir, mild cognitive impairment, Mini-Mental State Examination, positron emission tomography

DOI: 10.3233/JAD-190220

Citation: Journal of Alzheimer's Disease, vol. 70, no. 4, pp. 1197-1207, 2019