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Martyr A, Nelis SM, Morris RG, Marková IS, Roth I, Woods RT, Clare L. Exploring longitudinal changes in implicit awareness of dementia: An investigation of the emotional Stroop effect in healthy ageing and mild dementia. J Neuropsychol 2024; 18:226-238. [PMID: 37658549 DOI: 10.1111/jnp.12344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 09/03/2023]
Abstract
The aim of the study was to investigate responses to dementia-relevant words in healthy older people and to investigate changes in response over 20-months in people with early-stage dementia. An emotional Stroop task, using colour-naming dementia-relevant words, was used as an indicator of implicit awareness of dementia. Overall, 24 people with dementia and 24 healthy older people completed an emotional Stroop task (T1). People with dementia completed the same task again after 12 (T2) and 20 (T3) months. For people with dementia emotional Stroop performance was contrasted with ratings of explicit awareness based on a detailed interview at T1 and at T2. For healthy older people and people with dementia response times to dementia-relevant words were significantly longer than those for neutral words. The effect was absent for people with dementia at T3. This decline in the emotional Stroop effect was not associated with cognitive decline as measured by the MMSE. Ratings of explicit awareness showed no significant change over time. There was no association between explicit awareness and implicit awareness. Implicit awareness of the condition is evident in early-stage dementia and can be elicited even where there is reduced explicit awareness. The emotional Stroop effect for dementia-relevant words in people with dementia appears to decline over time, independently of changes in MMSE score, suggesting that implicit awareness fades as time progresses.
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Affiliation(s)
- Anthony Martyr
- Centre for Research in Ageing and Cognitive Health, University of Exeter Medical School, Exeter, UK
| | - Sharon M Nelis
- Centre for Research in Ageing and Cognitive Health, University of Exeter Medical School, Exeter, UK
| | - Robin G Morris
- Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Ivana S Marková
- Hull York Medical School, Allam Medical Building University of Hull, Hull, UK
| | - Ilona Roth
- School of Life, Health and Chemical Sciences, STEM Faculty, The Open University, Milton Keynes, UK
| | - Robert T Woods
- Dementia Services Development Centre (DSDC) Wales, School of Medical & Health Sciences, Bangor University, Bangor, UK
| | - Linda Clare
- Centre for Research in Ageing and Cognitive Health, University of Exeter Medical School, Exeter, UK
- NIHR Applied Research Collaboration South-West Peninsula, Exeter, UK
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2
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Zhao C, Huang WJ, Feng F, Zhou B, Yao HX, Guo YE, Wang P, Wang LN, Shu N, Zhang X. Abnormal characterization of dynamic functional connectivity in Alzheimer's disease. Neural Regen Res 2022; 17:2014-2021. [PMID: 35142691 PMCID: PMC8848607 DOI: 10.4103/1673-5374.332161] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Numerous studies have shown abnormal brain functional connectivity in individuals with Alzheimer's disease (AD) or amnestic mild cognitive impairment (aMCI). However, most studies examined traditional resting state functional connections, ignoring the instantaneous connection mode of the whole brain. In this case-control study, we used a new method called dynamic functional connectivity (DFC) to look for abnormalities in patients with AD and aMCI. We calculated dynamic functional connectivity strength from functional magnetic resonance imaging data for each participant, and then used a support vector machine to classify AD patients and normal controls. Finally, we highlighted brain regions and brain networks that made the largest contributions to the classification. We found differences in dynamic function connectivity strength in the left precuneus, default mode network, and dorsal attention network among normal controls, aMCI patients, and AD patients. These abnormalities are potential imaging markers for the early diagnosis of AD.
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Affiliation(s)
- Cui Zhao
- Department of Neurology, Second Medical Center, National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing; Department of Geriatrics, Affiliated Hospital of Chengde Medical University, Chengde, Hebei Province, China
| | - Wei-Jie Huang
- State Key Laboratory of Cognitive Neuroscience and Learning; Center for Collaboration and Innovation in Brain and Learning Sciences; Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
| | - Feng Feng
- Department of Neurology, First Medical Center, Chinese PLA General Hospital; Department of Neurology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Bo Zhou
- Department of Neurology, Second Medical Center, National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Hong-Xiang Yao
- Department of Radiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Yan-E Guo
- Department of Neurology, Second Medical Center, National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Pan Wang
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, China
| | - Lu-Ning Wang
- Department of Neurology, Second Medical Center, National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Ni Shu
- State Key Laboratory of Cognitive Neuroscience and Learning; Center for Collaboration and Innovation in Brain and Learning Sciences; Beijing Key Laboratory of Brain Imaging and Connectomics, Beijing Normal University, Beijing, China
| | - Xi Zhang
- Department of Neurology, Second Medical Center, National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
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3
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das Neves SP, Delivanoglou N, Da Mesquita S. CNS-Draining Meningeal Lymphatic Vasculature: Roles, Conundrums and Future Challenges. Front Pharmacol 2021; 12:655052. [PMID: 33995074 PMCID: PMC8113819 DOI: 10.3389/fphar.2021.655052] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/13/2021] [Indexed: 12/11/2022] Open
Abstract
A genuine and functional lymphatic vascular system is found in the meninges that sheath the central nervous system (CNS). This unexpected (re)discovery led to a reevaluation of CNS fluid and solute drainage mechanisms, neuroimmune interactions and the involvement of meningeal lymphatics in the initiation and progression of neurological disorders. In this manuscript, we provide an overview of the development, morphology and unique functional features of meningeal lymphatics. An outline of the different factors that affect meningeal lymphatic function, such as growth factor signaling and aging, and their impact on the continuous drainage of brain-derived molecules and meningeal immune cells into the cervical lymph nodes is also provided. We also highlight the most recent discoveries about the roles of the CNS-draining lymphatic vasculature in different pathologies that have a strong neuroinflammatory component, including brain trauma, tumors, and aging-associated neurodegenerative diseases like Alzheimer's and Parkinson's. Lastly, we provide a critical appraisal of the conundrums, challenges and exciting questions involving the meningeal lymphatic system that ought to be investigated in years to come.
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Affiliation(s)
| | | | - Sandro Da Mesquita
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
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4
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Wayfinding in People with Alzheimer’s Disease: Perspective Taking and Architectural Cognition—A Vision Paper on Future Dementia Care Research Opportunities. SUSTAINABILITY 2021. [DOI: 10.3390/su13031084] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Based on a targeted literature review, this vision paper emphasizes the importance of dementia-sensitive built space. The article specifically focuses on supporting spatial orientation and wayfinding for people living with dementia. First, we discuss types of wayfinding challenges, underlying processes, and consequences of spatial disorientation in the context of dementia of the Alzheimer’s type. Second, we focus on current efforts aimed at planning and evaluating dementia-sensitive built space, i.e., environmental design principles, interventions, evaluation tools, strategies, and planning processes. Third, we use our findings as a starting point for developing an interdisciplinary research vision aimed at encouraging further debates and research about: (1) the perspective of a person with dementia, specifically in the context of wayfinding and spatial orientation, and (2) how this perspective supplements planning and design processes of dementia-sensitive built space. We conclude that more closely considering the perspective of people with dementia supports the development of demographically sustainable future cities and care institutions.
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5
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Lam J, Lee J, Liu CY, Lozano AM, Lee DJ. Deep Brain Stimulation for Alzheimer's Disease: Tackling Circuit Dysfunction. Neuromodulation 2020; 24:171-186. [PMID: 33377280 DOI: 10.1111/ner.13305] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/07/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Treatments for Alzheimer's disease are urgently needed given its enormous human and economic costs and disappointing results of clinical trials targeting the primary amyloid and tau pathology. On the other hand, deep brain stimulation (DBS) has demonstrated success in other neurological and psychiatric disorders leading to great interest in DBS as a treatment for Alzheimer's disease. MATERIALS AND METHODS We review the literature on 1) circuit dysfunction in Alzheimer's disease and 2) DBS for Alzheimer's disease. Human and animal studies are reviewed individually. RESULTS There is accumulating evidence of neural circuit dysfunction at the structural, functional, electrophysiological, and neurotransmitter level. Recent evidence from humans and animals indicate that DBS has the potential to restore circuit dysfunction in Alzheimer's disease, similarly to other movement and psychiatric disorders, and may even slow or reverse the underlying disease pathophysiology. CONCLUSIONS DBS is an intriguing potential treatment for Alzheimer's disease, targeting circuit dysfunction as a novel therapeutic target. However, further exploration of the basic disease pathology and underlying mechanisms of DBS is necessary to better understand how circuit dysfunction can be restored. Additionally, robust clinical data in the form of ongoing phase III clinical trials are needed to validate the efficacy of DBS as a viable treatment.
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Affiliation(s)
- Jordan Lam
- USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA.,Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA
| | - Justin Lee
- USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA.,Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA
| | - Charles Y Liu
- USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA.,Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA
| | - Andres M Lozano
- Division of Neurological Surgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, ON, M5T 2S8, Canada
| | - Darrin J Lee
- USC Neurorestoration Center, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA.,Department of Neurological Surgery, Keck School of Medicine of USC, Los Angeles, CA, 90033, USA
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6
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Meade ME, Ahmad M, Fernandes MA. Drawing pictures at encoding enhances memory in healthy older adults and in individuals with probable dementia. AGING NEUROPSYCHOLOGY AND COGNITION 2019; 27:880-901. [PMID: 31833456 DOI: 10.1080/13825585.2019.1700899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
We explored the efficacy of drawing pictures as an encoding strategy to enhance memory performance in healthy older adults and individuals with probable dementia. In an incidental encoding phase, participants were asked to either draw a picture or write out each word from a set of 30 common nouns for 40 seconds each. Episodic memory for the target words was compared in a group of healthy older adults to individuals with probable dementia (MMSE/MOCA range 4 to 25). In two experiments we showed that recall and recognition performance was higher for words that were drawn than written out during encoding, for both participant groups. We suggest that incorporating visuo-perceptual information into memory enhanced performance by increasing reliance on visual-sensory brain regions, which are relatively intact in these populations. Our findings demonstrate that drawing is a valuable technique leading to measurable gains in memory performance for individuals with probable dementia.
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Affiliation(s)
- Melissa E Meade
- Department of Psychology, University of Waterloo , Waterloo, Canada
| | - Maahum Ahmad
- Department of Psychology, University of Waterloo , Waterloo, Canada
| | - Myra A Fernandes
- Department of Psychology, University of Waterloo , Waterloo, Canada
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7
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Liu CF, Padhy S, Ramachandran S, Wang VX, Efimov A, Bernal A, Shi L, Vaillant M, Ratnanather JT, Faria AV, Caffo B, Albert M, Miller MI. Using deep Siamese neural networks for detection of brain asymmetries associated with Alzheimer's Disease and Mild Cognitive Impairment. Magn Reson Imaging 2019; 64:190-199. [PMID: 31319126 PMCID: PMC6874905 DOI: 10.1016/j.mri.2019.07.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 07/01/2019] [Accepted: 07/02/2019] [Indexed: 01/12/2023]
Abstract
In recent studies, neuroanatomical volume and shape asymmetries have been seen during the course of Alzheimer's Disease (AD) and could potentially be used as preclinical imaging biomarkers for the prediction of Mild Cognitive Impairment (MCI) and AD dementia. In this study, a deep learning framework utilizing Siamese neural networks trained on paired lateral inter-hemispheric regions is used to harness the discriminative power of whole-brain volumetric asymmetry. The method uses the MRICloud pipeline to yield low-dimensional volumetric features of pre-defined atlas brain structures, and a novel non-linear kernel trick to normalize these features to reduce batch effects across datasets and populations. By working with the low-dimensional features, Siamese networks were shown to yield comparable performance to studies that utilize whole-brain MR images, with the advantage of reduced complexity and computational time, while preserving the biological information density. Experimental results also show that Siamese networks perform better in certain metrics by explicitly encoding the asymmetry in brain volumes, compared to traditional prediction methods that do not use the asymmetry, on the ADNI and BIOCARD datasets.
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Affiliation(s)
- Chin-Fu Liu
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Shreyas Padhy
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.
| | - Sandhya Ramachandran
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Victor X Wang
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Andrew Efimov
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Alonso Bernal
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Linyuan Shi
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Neuroscience, Johns Hopkins University, Baltimore, MD, USA
| | | | - J Tilak Ratnanather
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Andreia V Faria
- Department of Radiology, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Brian Caffo
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Marilyn Albert
- Department of Neurology, Johns Hopkins University, Baltimore, MD, USA
| | - Michael I Miller
- Center for Imaging Science, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
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8
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Ramzaoui H, Faure S, Spotorno S. Alzheimer's Disease, Visual Search, and Instrumental Activities of Daily Living: A Review and a New Perspective on Attention and Eye Movements. J Alzheimers Dis 2019; 66:901-925. [PMID: 30400086 DOI: 10.3233/jad-180043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Many instrumental activities of daily living (IADLs), like cooking and managing finances and medications, involve finding efficiently and in a timely manner one or several objects within complex environments. They may thus be disrupted by visual search deficits. These deficits, present in Alzheimer's disease (AD) from its early stages, arise from impairments in multiple attentional and memory mechanisms. A growing body of research on visual search in AD has examined several factors underlying search impairments in simple arrays. Little is known about how AD patients search in real-world scenes and in real settings, and about how such impairments affect patients' functional autonomy. Here, we review studies on visuospatial attention and visual search in AD. We then consider why analysis of patients' oculomotor behavior is promising to improve understanding of the specific search deficits in AD, and of their role in impairing IADL performance. We also highlight why paradigms developed in research on real-world scenes and real settings in healthy individuals are valuable to investigate visual search in AD. Finally, we indicate future research directions that may offer new insights to improve visual search abilities and autonomy in AD patients.
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Affiliation(s)
- Hanane Ramzaoui
- Laboratoire d'Anthropologie et de Psychologie Cliniques, Cognitives et Sociales, Université Côte d'Azur, France
| | - Sylvane Faure
- Laboratoire d'Anthropologie et de Psychologie Cliniques, Cognitives et Sociales, Université Côte d'Azur, France
| | - Sara Spotorno
- School of Psychology, University of Aberdeen, UK.,Institute of Neuroscience and Psychology, University of Glasgow, UK
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9
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Jeon SG, Hong SB, Nam Y, Tae J, Yoo A, Song EJ, Kim KI, Lee D, Park J, Lee SM, Kim JI, Moon M. Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications. Ageing Res Rev 2019; 55:100945. [PMID: 31434007 DOI: 10.1016/j.arr.2019.100945] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022]
Abstract
Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.
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10
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He H, Xu P, Wu T, Chen Y, Wang J, Qiu Y, Fan J, Guan Q, Luo Y. Reduced Capacity of Cognitive Control in Older Adults with Mild Cognitive Impairment. J Alzheimers Dis 2019; 71:185-200. [PMID: 31356201 DOI: 10.3233/jad-181006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cognitive control for the coordination of mental operations is essential in normal cognitive functioning of daily life. Although the decline of cognitive control in older adults with mild cognitive impairment (MCI) has been demonstrated, whether this decline is a core deficit in MCI remains unclear. In this study, we employed a perceptual decision-making task to estimate the capacity of cognitive control (CCC) in older adults with MCI (n = 55) and the age-, sex-, and education-matched healthy controls (HC, n = 55) selected based on a commonly used battery of ten neuropsychological tests in five cognitive domains. We found that the CCC was significantly correlated to the neuropsychological measures of the battery. The mean CCC was significantly lower in the MCI group (3.06 bps) than in the HC group (3.59 bps) and significantly lower in the amnestic MCI subgroup (2.90 bps) than in the nonamnestic MCI subgroup (3.22 bps). In detecting and classifying MCI using machine learning, the classifier with the CCC as the input feature outperformed the overall classification with neuropsychological measures in a single cognitive domain. The classification performance was significantly increased when the CCC was included as a feature in addition to measures in a single domain, and the CCC served as a key feature in optimal classifiers with inputs from multiple domains. These results support the hypothesis that the decline in cognitive control is a core deficit in MCI and suggest that the CCC may serve as a key index in the diagnosis of MCI.
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Affiliation(s)
- Hao He
- School of Psychology, Shenzhen University, Shenzhen, China.,Shenzhen Key Laboratory of Affective and Social Cognitive Science, Shenzhen University, Shenzhen, China.,Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China.,Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
| | - Pengfei Xu
- School of Psychology, Shenzhen University, Shenzhen, China.,Shenzhen Key Laboratory of Affective and Social Cognitive Science, Shenzhen University, Shenzhen, China.,Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China.,Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
| | - Tingting Wu
- Department of Psychology, Queens College, The City University of New York, Queens, NY, USA
| | - Yiqi Chen
- School of Psychology, Shenzhen University, Shenzhen, China
| | - Jing Wang
- School of Psychology, Shenzhen University, Shenzhen, China
| | - Yuehong Qiu
- School of Psychology, Shenzhen University, Shenzhen, China
| | - Jin Fan
- Department of Psychology, Queens College, The City University of New York, Queens, NY, USA
| | - Qing Guan
- School of Psychology, Shenzhen University, Shenzhen, China.,Shenzhen Key Laboratory of Affective and Social Cognitive Science, Shenzhen University, Shenzhen, China.,Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China.,Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
| | - Yuejia Luo
- School of Psychology, Shenzhen University, Shenzhen, China.,Shenzhen Key Laboratory of Affective and Social Cognitive Science, Shenzhen University, Shenzhen, China.,Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China.,Center for Brain Disorders and Cognitive Sciences, Shenzhen University, Shenzhen, China
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11
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Vila-Castelar C, Ly JJ, Kaplan L, Van Dyk K, Berger JT, Macina LO, Stewart JL, Foldi NS. Attention Measures of Accuracy, Variability, and Fatigue Detect Early Response to Donepezil in Alzheimer's Disease: A Randomized, Double-blind, Placebo-Controlled Pilot Trial. Arch Clin Neuropsychol 2019; 34:277-289. [PMID: 29635383 PMCID: PMC6487534 DOI: 10.1093/arclin/acy032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 03/03/2018] [Accepted: 03/20/2018] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE Donepezil is widely used to treat Alzheimer's disease (AD), but detecting early response remains challenging for clinicians. Acetylcholine is known to directly modulate attention, particularly under high cognitive conditions, but no studies to date test whether measures of attention under high load can detect early effects of donepezil. We hypothesized that load-dependent attention tasks are sensitive to short-term treatment effects of donepezil, while global and other domain-specific cognitive measures are not. METHOD This longitudinal, randomized, double-blind, placebo-controlled pilot trial (ClinicalTrials.gov Identifier: NCT03073876) evaluated 23 participants newly diagnosed with AD initiating de novo donepezil treatment (5 mg). After baseline assessment, participants were randomized into Drug (n = 12) or Placebo (n = 11) groups, and retested after approximately 6 weeks. Cognitive assessment included: (a) attention tasks (Foreperiod Effect, Attentional Blink, and Covert Orienting tasks) measuring processing speed, top-down accuracy, orienting, intra-individual variability, and fatigue; (b) global measures (Alzheimer's Disease Assessment Scale-Cognitive Subscale, Mini-Mental Status Examination, Dementia Rating Scale); and (c) domain-specific measures (memory, language, visuospatial, and executive function). RESULTS The Drug but not the Placebo group showed benefits of treatment at high-load measures by preserving top-down accuracy, improving intra-individual variability, and averting fatigue. In contrast, other global or cognitive domain-specific measures could not detect treatment effects over the same treatment interval. CONCLUSIONS The pilot-study suggests that attention measures targeting accuracy, variability, and fatigue under high-load conditions could be sensitive to short-term cholinergic treatment. Given the central role of acetylcholine in attentional function, load-dependent attentional measures may be valuable cognitive markers of early treatment response.
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Affiliation(s)
- Clara Vila-Castelar
- Department of Psychology, Queens College and The Graduate Center, City University of New York, New York, NY, USA
- Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jenny J Ly
- eResearch Technology, Inc., Boston, MA, USA
| | - Lillian Kaplan
- Department of Occupational Therapy, York College, City University of New York, New York, NY, USA
| | - Kathleen Van Dyk
- Department of Psychiatry, UCLA - Semel Institute for Neuroscience & Human Behavior and Jonsson Comprehensive Cancer Center, Los Angeles, CA, USA
| | - Jeffrey T Berger
- Division of Palliative Medicine and Bioethics, Department of Medicine, NYU Winthrop Hospital, Mineola, NY, USA
| | - Lucy O Macina
- Division of Geriatrics, Department of Medicine, NYU Winthrop Hospital, Mineola, NY, USA
| | - Jennifer L Stewart
- Department of Psychology, Queens College and The Graduate Center, City University of New York, New York, NY, USA
| | - Nancy S Foldi
- Department of Psychology, Queens College and The Graduate Center, City University of New York, New York, NY, USA
- Division of Geriatrics, Department of Medicine, NYU Winthrop Hospital, Mineola, NY, USA
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12
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Sacco G, Ben-Sadoun G, Bourgeois J, Fabre R, Manera V, Robert P. Comparison between a Paper-Pencil Version and Computerized Version for the Realization of a Neuropsychological Test: The Example of the Trail Making Test. J Alzheimers Dis 2019; 68:1657-1666. [DOI: 10.3233/jad-180396] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Guillaume Sacco
- Université Côte d’Azur, CoBTeK lab IA, France
- Université Côte d’Azur, CHU Pôle Réhabilitation Autonomie Vieillissement, CMRR, France
| | | | | | | | | | - Philippe Robert
- Université Côte d’Azur, CoBTeK lab IA, France
- Université Côte d’Azur, CHU Pôle Réhabilitation Autonomie Vieillissement, CMRR, France
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13
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Rivera O, McHan L, Konadu B, Patel S, Sint Jago S, Talbert ME. A high-fat diet impacts memory and gene expression of the head in mated female Drosophila melanogaster. J Comp Physiol B 2019; 189:179-198. [PMID: 30810797 PMCID: PMC6711602 DOI: 10.1007/s00360-019-01209-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 02/12/2019] [Accepted: 02/17/2019] [Indexed: 12/25/2022]
Abstract
Obesity predisposes humans to a range of life-threatening comorbidities, including type 2 diabetes and cardiovascular disease. Obesity also aggravates neural pathologies, such as Alzheimer's disease, but this class of comorbidity is less understood. When Drosophila melanogaster (flies) are exposed to high-fat diet (HFD) by supplementing a standard medium with coconut oil, they adopt an obese phenotype of decreased lifespan, increased triglyceride storage, and hindered climbing ability. The latter development has been previously regarded as a potential indicator of neurological decline in fly models of neurodegenerative disease. Our objective was to establish the obesity phenotype in Drosophila and identify a potential correlation, if any, between obesity and neurological decline through behavioral assays and gene expression microarray. We found that mated female w1118 flies exposed to HFD maintained an obese phenotype throughout adult life starting at 7 days, evidenced by increased triglyceride stores, diminished life span, and impeded climbing ability. While climbing ability worsened cumulatively between 7 and 14 days of exposure to HFD, there was no corresponding alteration in triglyceride content. Microarray analysis of the mated female w1118 fly head revealed HFD-induced changes in expression of genes with functions in memory, metabolism, olfaction, mitosis, cell signaling, and motor function. Meanwhile, an Aversive Phototaxis Suppression assay in mated female flies indicated reduced ability to recall an entrained memory 6 h after training. Overall, our results support the suitability of mated female flies for examining connections between diet-induced obesity and nervous or neurobehavioral pathology, and provide many directions for further investigation.
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Affiliation(s)
- Osvaldo Rivera
- Program in Biology, School of Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA, 71209, USA
| | - Lara McHan
- Program in Biology, School of Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA, 71209, USA
| | - Bridget Konadu
- Program in Biology, School of Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA, 71209, USA
| | - Sumitkumar Patel
- Program in Biology, School of Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA, 71209, USA
| | - Silvienne Sint Jago
- Program in Biology, School of Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA, 71209, USA
| | - Matthew E Talbert
- Program in Biology, School of Sciences, University of Louisiana at Monroe, 700 University Avenue, Monroe, LA, 71209, USA.
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Mueller SM, Arias MG, Mejuto Vázquez G, Schiebener J, Brand M, Wegmann E. Decision support in patients with mild Alzheimer's disease. J Clin Exp Neuropsychol 2019; 41:484-496. [PMID: 30835634 DOI: 10.1080/13803395.2019.1585517] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Making advantageous decisions is a key competence of individuals of all ages. However, previous studies reported a reduction of this competence in patients with neurodegenerative diseases such as Alzheimer's disease, which is explained by impairments of executive functions such as cognitive flexibility or working memory. While previous findings from healthy participants with reduced executive functions showed that support can improve decision making under risk, the study at hand aimed to investigate this effect in patients with mild Alzheimer's disease (mAD). METHOD A group of elderly individuals diagnosed with mAD (n = 14; mean Mini-Mental State Examination, MMSE = 24.14, SD = 3.18) and a group of healthy age-matched controls (n = 14; mean MMSE = 29.29, SD = 1.98) performed the Game of Dice Task (GDT) three times (t0, t1, t2) with intervals of five to nine days between each: The standard GDT plus other neurocognitive tasks (t0), the GDT with decision support (t1), and again the standard GDT (t2). RESULTS At any time, mAD patients made more disadvantageous decisions than controls. However, the decision-making performance of mAD patients improved significantly with decision support. Interestingly, when the standard GDT was played again (t2), mAD patients' performance remained similar to the performance in the GDT with decision support (t1). GDT performance correlated consistently with executive function measures in the control group, but only at t0 in the mAD group. CONCLUSIONS The findings indicate that supportive information about the riskiness of options can compensate for mAD-related deficits in decision making under risk. Thus, decision support can improve the quality of mAD patients' decisions. Further, it may prevent mAD patients from making highly risky decisions in similar situations in the future. The persistence of decision support should be further investigated as it has relevant implications for everyday decisions that include risks.
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Affiliation(s)
- Silke M Mueller
- a General Psychology: Cognition and Center for Behavioral Addiction Research (CeBAR) , University of Duisburg-Essen , Duisburg , Germany
| | - María García Arias
- b Gabinete de Orientación Educativa , University Francisco de Vitoria , Madrid , Spain
| | - Gema Mejuto Vázquez
- c Fundación Vianorte-Laguna , Hospital Centro de Cuidados Laguna , Madrid , Spain
| | - Johannes Schiebener
- a General Psychology: Cognition and Center for Behavioral Addiction Research (CeBAR) , University of Duisburg-Essen , Duisburg , Germany
| | - Matthias Brand
- a General Psychology: Cognition and Center for Behavioral Addiction Research (CeBAR) , University of Duisburg-Essen , Duisburg , Germany.,d Erwin L. Hahn Institute for Magnetic Resonance Imaging , Essen , Germany
| | - Elisa Wegmann
- a General Psychology: Cognition and Center for Behavioral Addiction Research (CeBAR) , University of Duisburg-Essen , Duisburg , Germany
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15
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Wei EX, Oh ES, Harun A, Ehrenburg M, Xue QL, Simonsick E, Agrawal Y. Increased Prevalence of Vestibular Loss in Mild Cognitive Impairment and Alzheimer's Disease. Curr Alzheimer Res 2019; 16:1143-1150. [PMID: 31418661 PMCID: PMC10696591 DOI: 10.2174/1567205016666190816114838] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/29/2019] [Accepted: 05/17/2019] [Indexed: 01/20/2023]
Abstract
BACKGROUND/AIMS Recent evidence has shown that Alzheimer's Disease (AD) patients have reduced vestibular function relative to healthy controls. In this study, we evaluated whether patients with Mild Cognitive Impairment (MCI) also have reduced vestibular function relative to controls, and compared the level of vestibular impairment between MCI and AD patients. METHODS Vestibular physiologic function was assessed in 77 patients (26 MCI, 51 AD) and 295 matched controls using 3 clinical vestibular tests. The association between vestibular loss and cognitive impairment was evaluated using conditional logistic regression models. RESULTS Individuals with vestibular impairment had a 3 to 4-fold increased odds of being in the MCI vs. control group (p-values < 0.05). MCI patients had a level of vestibular impairment that was intermediate between controls and AD. CONCLUSION These findings suggest a dose-response relationship between vestibular loss and cognitive status, and support the hypothesis that vestibular loss contributes to cognitive decline.
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Affiliation(s)
- Eric X. Wei
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA
| | - Esther S. Oh
- Department of Medicine, Johns Hopkins University, School of Medicine, 5200 Eastern Ave, Seventh Floor, Baltimore, MD 21224, USA
| | - Aisha Harun
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA
| | - Matthew Ehrenburg
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA
| | - Qian-Li Xue
- Division of Geriatric Medicine and Gerontology, Department of Medicine, Johns Hopkins University, School of Medicine, 2024 E. Monument Street, Suite 2-722, Baltimore, MD 21205, USA
| | - Eleanor Simonsick
- National Institute on Aging, National Institutes of Health, 3001 S. Hanover Street, 5th Floor, Baltimore, MD 21225, USA
| | - Yuri Agrawal
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins University, School of Medicine, 601 N. Caroline Street, Baltimore, MD 21287, USA
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Yu Q, Guo P, Li D, Zuo L, Lian T, Yu S, Hu Y, Liu L, Jin Z, Wang R, Piao Y, Li L, Wang X, Zhang W. Olfactory Dysfunction and Its Relationship with Clinical Symptoms of Alzheimer Disease. Aging Dis 2018; 9:1084-1095. [PMID: 30574420 PMCID: PMC6284764 DOI: 10.14336/ad.2018.0819] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 08/19/2018] [Indexed: 11/04/2022] Open
Abstract
Our study aimed to analyse the olfactory dysfunction (OD) evaluations between self-report, the Hyposmia Rating Scale (HRS) and the Sniffin’ Sticks test, and the relationship between OD and clinical features of AD. Sixty patients with AD dementia, 37 patients with mild cognitive impairment (MCI) due to AD and 30 healthy controls were consecutively recruited. Olfactory function was evaluated by self-report, HRS and Sniffin’ Sticks test. Patients were divided into AD with OD (AD-OD) and AD with no OD (AD-NOD) groups based on the results of the Sniffin’ Sticks test. Cognitive symptoms and neuropsychiatric symptoms were assessed by corresponding scales, and activities of daily living (ADL) were assessed by the ADL scale. In the control, MCI due to AD and AD dementia groups, the frequency of OD was 10.0%, 13.5% and 18.3%, respectively, by self-report; 6.7%, 24.3% and 48.3%, respectively, by HRS; and 3.3%, 13.5% and 65.0%, respectively, by the Sniffin’ Sticks test. Compared to the results of the Sniffin’ Sticks test, the diagnostic coincidence rates of OD by HRS in patients with MCI due to AD and AD dementia were 89.2% and 66.7%, respectively. Compared to the AD-NOD group, the scores of global cognition and memory, visuospatial ability and attention were all decreased (P<0.05), the apathy score was increased (P<0.05), and the ADL score was elevated (P<0.01). The frequency and accuracy of OD by self-report is relatively low. HRS can be used for screening olfaction in patients with MCI due to AD. The Sniffin’ Sticks test can be used for validating OD in AD patients. AD-OD patients have severe impairments in global cognition and multiple cognitive domains of memory, visuospatial ability and attention, as well as neuropsychiatric symptoms of apathy, and thus have seriously compromised ADL.
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Affiliation(s)
- Qiujin Yu
- 1Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Peng Guo
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Danning Li
- 1Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Lijun Zuo
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Tenghong Lian
- 1Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Shuyang Yu
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Yang Hu
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Li Liu
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Zhao Jin
- 1Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Ruidan Wang
- 1Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Yingshan Piao
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Lixia Li
- 2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Xiaomin Wang
- 3Department of Physiology, Capital Medical University, Beijing, 100069, China.,4Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing, 100069, China.,5Center of Parkinson Disease, Beijing Institute for Brain Disorders, Beijing, 100069, China.,6Beijing Key Laboratory on Parkinson Disease, Beijing, 100053, China
| | - Wei Zhang
- 1Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China.,2Department of Geriatrics, Beijing Tiantan Hospital, Capital Medical University, Beijing, 100050, China.,4Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing, 100069, China.,5Center of Parkinson Disease, Beijing Institute for Brain Disorders, Beijing, 100069, China.,6Beijing Key Laboratory on Parkinson Disease, Beijing, 100053, China.,7China National Clinical Research Center for Neurological Diseases, Beijing, 100050, China
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17
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Shah C, Liu J, Lv P, Sun H, Xiao Y, Liu J, Zhao Y, Zhang W, Yao L, Gong Q, Lui S. Age Related Changes in Topological Properties of Brain Functional Network and Structural Connectivity. Front Neurosci 2018; 12:318. [PMID: 29867329 PMCID: PMC5962656 DOI: 10.3389/fnins.2018.00318] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 04/24/2018] [Indexed: 02/05/2023] Open
Abstract
Introduction: There are still uncertainties about the true nature of age related changes in topological properties of the brain functional network and its structural connectivity during various developmental stages. In this cross- sectional study, we investigated the effects of age and its relationship with regional nodal properties of the functional brain network and white matter integrity. Method: DTI and fMRI data were acquired from 458 healthy Chinese participants ranging from age 8 to 81 years. Tractography was conducted on the DTI data using FSL. Graph Theory analyses were conducted on the functional data yielding topological properties of the functional network using SPM and GRETNA toolbox. Two multiple regressions were performed to investigate the effects of age on nodal topological properties of the functional brain network and white matter integrity. Result: For the functional studies, we observed that regional nodal characteristics such as node betweenness were decreased while node degree and node efficiency was increased in relation to increasing age. Perversely, we observed that the relationship between nodal topological properties and fasciculus structures were primarily positive for nodal betweenness but negative for nodal degree and nodal efficiency. Decrease in functional nodal betweenness was primarily located in superior frontal lobe, right occipital lobe and the global hubs. These brain regions also had both direct and indirect anatomical relationships with the 14 fiber bundles. A linear age related decreases in the Fractional anisotropy (FA) value was found in the callosum forceps minor. Conclusion: These results suggests that age related differences were more pronounced in the functional than in structural measure indicating these measures do not have direct one-to-one mapping. Our study also indicates that the fiber bundles with longer fibers exhibited a more pronounced effect on the properties of functional network.
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Affiliation(s)
- Chandan Shah
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Jia Liu
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Peilin Lv
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Huaiqiang Sun
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Yuan Xiao
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Jieke Liu
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Youjin Zhao
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Wenjing Zhang
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Li Yao
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Qiyong Gong
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
| | - Su Lui
- Huaxi MR Research Center, Department of Radiology, West China Hospital of Sichuan University, Chengdu, China
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Wei EX, Oh ES, Harun A, Ehrenburg M, Agrawal Y. Vestibular Loss Predicts Poorer Spatial Cognition in Patients with Alzheimer’s Disease. J Alzheimers Dis 2018; 61:995-1003. [DOI: 10.3233/jad-170751] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Eric X. Wei
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Esther S. Oh
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Aisha Harun
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Matthew Ehrenburg
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuri Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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19
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Lee ACH, Barense MD, Graham KS. The Contribution of the Human Medial Temporal Lobe to Perception: Bridging the Gap between Animal and Human Studies. ACTA ACUST UNITED AC 2018; 58:300-25. [PMID: 16194971 DOI: 10.1080/02724990444000168] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The medial temporal lobe (MTL) has been considered traditionally to subserve declarative memory processes only. Recent studies in nonhuman primates suggest, however, that the MTL may also be critical to higher order perceptual processes, with the hippocampus and perirhinal cortex being involved in scene and object perception, respectively. The current article reviews the human neuropsychological literature to determine whether there is any evidence to suggest that these same views may apply to the human MTL. Although the majority of existing studies report intact perception following MTL damage in human amnesics, there have been recent studies that suggest that when scene and object perception are assessed systematically, signifi-cant impairments in perception become apparent. These findings have important implications for current mnemonic theories of human MTL function and our understanding of human amnesia as a result of MTL lesions.
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Affiliation(s)
- Andy C H Lee
- MRC Cognition and Brain Sciences Unit, Cambridge, UK.
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20
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McCarthy F, Burns WJ, Sellers AH. Discrepancies between Premorbid and Current IQ as a Function of Progressive Mental Deterioration. Percept Mot Skills 2016; 100:69-76. [PMID: 15773695 DOI: 10.2466/pms.100.1.69-76] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The declining cognitive functioning typically found in patients with Alzheimer's disease presents an opportunity to study that decline. The changing magnitude of ever widening discrepancies between premorbid estimators of IQ and observed IQ increases as severity of the disease increases. Premorbid IQs estimated by these scores (the National Adult Reading Test–Revised, the reading tests of the Revised and Third Editions of the Wide Range Achievement Test, and a demographically based regression index for the Wechsler Adult Intelligence Scale–Revised) had relatively similar discrepancies from obtained WAIS–R Full Scale IQs in samples of normal elderly ( n = 30), and elderly patients diagnosed with mild ( n = 30) and moderate Alzheimer's disease ( n = 30) dementia. The discrepancies became larger, regardless of premorbid estimator, as disease severity progressed from none to mild to moderate across the samples.
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21
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Wachinger C, Salat DH, Weiner M, Reuter M. Whole-brain analysis reveals increased neuroanatomical asymmetries in dementia for hippocampus and amygdala. Brain 2016; 139:3253-3266. [PMID: 27913407 PMCID: PMC5840883 DOI: 10.1093/brain/aww243] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/05/2016] [Accepted: 08/12/2016] [Indexed: 01/18/2023] Open
Abstract
Structural magnetic resonance imaging data are frequently analysed to reveal morphological changes of the human brain in dementia. Most contemporary imaging biomarkers are scalar values, such as the volume of a structure, and may miss the localized morphological variation of early presymptomatic disease progression. Neuroanatomical shape descriptors, however, can represent complex geometric information of individual anatomical regions and may demonstrate increased sensitivity in association studies. Yet, they remain largely unexplored. In this article, we introduce a novel technique to study shape asymmetries of neuroanatomical structures across subcortical and cortical brain regions. We demonstrate that neurodegeneration of subcortical structures in Alzheimer's disease is not symmetric. The hippocampus shows a significant increase in asymmetry longitudinally and both hippocampus and amygdala show a significantly higher asymmetry cross-sectionally concurrent with disease severity above and beyond an ageing effect. Our results further suggest that the asymmetry in these structures is undirectional and that primarily the anterior hippocampus becomes asymmetric. Based on longitudinal asymmetry measures we subsequently study the progression from mild cognitive impairment to dementia, demonstrating that shape asymmetry in hippocampus, amygdala, caudate and cortex is predictive of disease onset. The same analyses on scalar volume measurements did not produce any significant results, indicating that shape asymmetries, potentially induced by morphometric changes in subnuclei, rather than size asymmetries are associated with disease progression and can yield a powerful imaging biomarker for the early presymptomatic classification and prediction of Alzheimer's disease. Because literature has focused on contralateral volume differences, subcortical disease lateralization may have been overlooked thus far.
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Affiliation(s)
- Christian Wachinger
- 1 A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA
- 2 Department of Child and Adolescent Psychiatry, Psychosomatic and Psychotherapy, Ludwig-Maximilian-University, Munich, Germany
- 3 Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David H Salat
- 1 A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA
- 4 Department of Radiology, Harvard Medical School, Boston MA, USA
| | - Michael Weiner
- 5 University of California, San Francisco, San Francisco VA Medical Center, San Francisco CA, 94121 USA
| | - Martin Reuter
- 1 A.A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA
- 3 Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, Cambridge, MA, USA
- 4 Department of Radiology, Harvard Medical School, Boston MA, USA
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22
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Noroozian M. Alzheimer's Disease: Prototype of Cognitive Deterioration, Valuable Lessons to Understand Human Cognition. Neurol Clin 2016; 34:69-131. [PMID: 26613996 DOI: 10.1016/j.ncl.2015.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
It is important for neurologists to become more familiar with neuropsychological evaluation for Alzheimer disease. The growth of this method in research, as an available, inexpensive, and noninvasive diagnostic approach, which can be administered even by non-specialist-trained examiners, makes this knowledge more necessary than ever. Such knowledge has a basic role in planning national programs in primary health care systems for prevention and early detection of Alzheimer disease. This is more crucial in developing countries, which have higher rates of dementia prevalence along with cardiovascular risk factors, lack of public knowledge about dementia, and limited social support. In addition compared to the neurological hard signs which are tangible and measurable, the concept of cognition seems to be more difficult for the neurologists to evaluate and for the students to understand. Dementia in general and Alzheimer's disease as the prototype of cognitive disorders specifically, play an important role to explore all domains of human cognition through its symptomatology and neuropsychological deficits.
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Affiliation(s)
- Maryam Noroozian
- Memory and Behavioral Neurology Division, Department of Psychiatry, Roozbeh Hospital, Tehran University of Medical Sciences, 606 South Kargar Avenue, Tehran 1333795914, Iran.
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23
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Kazim SF, Iqbal K. Neurotrophic factor small-molecule mimetics mediated neuroregeneration and synaptic repair: emerging therapeutic modality for Alzheimer's disease. Mol Neurodegener 2016; 11:50. [PMID: 27400746 PMCID: PMC4940708 DOI: 10.1186/s13024-016-0119-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Accepted: 07/02/2016] [Indexed: 11/10/2022] Open
Abstract
Alzheimer's disease (AD) is an incurable and debilitating chronic progressive neurodegenerative disorder which is the leading cause of dementia worldwide. AD is a heterogeneous and multifactorial disorder, histopathologically characterized by the presence of amyloid β (Aβ) plaques and neurofibrillary tangles composed of Aβ peptides and abnormally hyperphosphorylated tau protein, respectively. Independent of the various etiopathogenic mechanisms, neurodegeneration is a final common outcome of AD neuropathology. Synaptic loss is a better correlate of cognitive impairment in AD than Aβ or tau pathologies. Thus a highly promising therapeutic strategy for AD is to shift the balance from neurodegeneration to neuroregeneration and synaptic repair. Neurotrophic factors, by virtue of their neurogenic and neurotrophic activities, have potential for the treatment of AD. However, the clinical therapeutic usage of recombinant neurotrophic factors is limited because of the insurmountable hurdles of unfavorable pharmacokinetic properties, poor blood-brain barrier (BBB) permeability, and severe adverse effects. Neurotrophic factor small-molecule mimetics, in this context, represent a potential strategy to overcome these short comings, and have shown promise in preclinical studies. Neurotrophic factor small-molecule mimetics have been the focus of intense research in recent years for AD drug development. Here, we review the relevant literature regarding the therapeutic beneficial effect of neurotrophic factors in AD, and then discuss the recent status of research regarding the neurotrophic factor small-molecule mimetics as therapeutic candidates for AD. Lastly, we summarize the preclinical studies with a ciliary neurotrophic factor (CNTF) small-molecule peptide mimetic, Peptide 021 (P021). P021 is a neurogenic and neurotrophic compound which enhances dentate gyrus neurogenesis and memory processes via inhibiting leukemia inhibitory factor (LIF) signaling pathway and increasing brain-derived neurotrophic factor (BDNF) expression. It robustly inhibits tau abnormal hyperphosphorylation via increased BDNF mediated decrease in glycogen synthase kinase-3β (GSK-3β, major tau kinase) activity. P021 is a small molecular weight, BBB permeable compound with suitable pharmacokinetics for oral administration, and without adverse effects associated with native CNTF or BDNF molecule. P021 has shown beneficial therapeutic effect in several preclinical studies and has emerged as a highly promising compound for AD drug development.
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Affiliation(s)
- Syed Faraz Kazim
- />Department of Neurochemistry, and SUNY Downstate/NYSIBR Program in Developmental Neuroscience, New York State Institute for Basic Research (NYSIBR), 1050 Forest Hill Road, Staten Island, NY 10314 USA
- />Graduate Program in Neural and Behavioral Science, and Department of Physiology and Pharmacology, State University of New York (SUNY) Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203 USA
| | - Khalid Iqbal
- />Department of Neurochemistry, and SUNY Downstate/NYSIBR Program in Developmental Neuroscience, New York State Institute for Basic Research (NYSIBR), 1050 Forest Hill Road, Staten Island, NY 10314 USA
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Lin YC, Hsu WC, Wu CK, Chang WH, Wu KPH, Wong AMK. Comparison of motor performance of upper and lower extremities in dual-task tests in patients with mild Alzheimer's dementia. Aging Clin Exp Res 2016; 28:491-6. [PMID: 26341489 DOI: 10.1007/s40520-015-0441-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 08/12/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Alzheimer's dementia (AD) is a progressive disease that threatens the self-care and quality of life of elderly people. Early diagnosis and early treatment are crucial. AIM To examine the difference in executive function of patients with AD by analyzing their performance in gait analysis (Vicon MX system) and a trial making test (TMT) while counting forward or backward. METHODS Ten elderly persons who had been diagnosed by neurological specialists with mild AD were selected as study participants. Of these patients, 2 were men and 8 were women, and the average age was 74.0 ± 8.6 years. An additional group of 10 elderly persons without AD and matched according to age and sex constituted a control group. RESULTS The average Mini-Mental State Examination score was 17.7 ± 4.1, and the average clinical dementia rating scale score was 0.8 ± 0.3. We found that backward counting of 3 digits during gait performance in mild AD patients elicited substantial changes in velocity, cadence, coefficient of variation of the stride length, and stride time compared with those of the control group. Regarding upper extremity performance, all TMT tasks were highly sensitive in revealing differences in reaction time between the mild AD group and the control group. DISCUSSION Dual-task challenges for examining gait parameters and TMT performance can reveal obvious impairment of executive motor function in patients with very mild AD. CONCLUSION Dual-task motor tests of the upper extremities can be used as screening tools for detecting AD at an early stage.
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Affiliation(s)
- Yin-Chou Lin
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
| | - Wen-Chuin Hsu
- Department of Neurology and Dementia Center, Chang Gung Memorial Hospital, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
- School of Medicine, Chang Gung University, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
| | - Chih-Kuan Wu
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
| | - Wei-Han Chang
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taipei, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
| | - Katie Pei-Hsuan Wu
- School of Medicine, Chang Gung University, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China
| | - Alice M K Wong
- Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taoyuan, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China.
- School of Medicine, Chang Gung University, 5, Fu-Hsin St., Kwei-Shan, Tao-Yuan, 333, Taiwan, Republic of China.
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Impaired Cholinergic Excitation of Prefrontal Attention Circuitry in the TgCRND8 Model of Alzheimer's Disease. J Neurosci 2016; 35:12779-91. [PMID: 26377466 DOI: 10.1523/jneurosci.4501-14.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Attention deficits in Alzheimer's disease can exacerbate its other cognitive symptoms, yet relevant disruptions of key prefrontal circuitry are not well understood. Here, in the TgCRND8 mouse model of this neurological disorder, we demonstrate and characterize a disruption of cholinergic excitation in the major corticothalamic layer of the prefrontal cortex, in which modulation by acetylcholine is essential for optimal attentional function. Using electrophysiology with concurrent multiphoton imaging, we show that layer 6 pyramidal cells are unable to sustain cholinergic excitation to the same extent as their nontransgenic littermate controls, as a result of the excessive activation of calcium-activated hyperpolarizing conductances. We report that cholinergic excitation can be improved in TgCRND8 cortex by pharmacological blockade of SK channels, suggesting a novel target for the treatment of cognitive dysfunction in Alzheimer's disease. SIGNIFICANCE STATEMENT Alzheimer's disease is accompanied by attention deficits that exacerbate its other cognitive symptoms. In brain slices of a mouse model of this neurological disorder, we demonstrate, characterize, and rescue impaired cholinergic excitation of neurons essential for optimal attentional performance. In particular, we show that the excessive activation of a calcium-activated potassium conductance disrupts the acetylcholine excitation of prefrontal layer 6 pyramidal neurons and that its blockade normalizes responses. These findings point to a novel potential target for the treatment of cognitive dysfunction in Alzheimer's disease.
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Sun YH, Nfor ON, Huang JY, Liaw YP. Association between dental amalgam fillings and Alzheimer's disease: a population-based cross-sectional study in Taiwan. ALZHEIMERS RESEARCH & THERAPY 2015; 7:65. [PMID: 26560125 PMCID: PMC4642684 DOI: 10.1186/s13195-015-0150-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/28/2015] [Indexed: 11/26/2022]
Abstract
Introduction The potential effects of amalgam fillings on the development of Alzheimer’s disease (AD) are not well understood. The aim of the study was to evaluate the association between dental amalgam fillings and Alzheimer’s disease in Taiwanese population aged 65 and older. Methods Data were retrieved from the Longitudinal Health Insurance Database (LHID 2005 and 2010). The study enrolled 1,943,702 beneficiaries from the LHID database. After excluding death cases and individuals aged 65 and under, 207,587 enrollees were finally involved in the study. Dental amalgam fillings are coded as 89001C, 89002C, 89003C, 89101C, 89102C, or 89103C in the national health insurance research database (NHIRD). Alzheimer’s disease was diagnosed using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes 331.0. Results Individuals exposed to amalgam fillings had higher risk of Alzheimer’s disease (odds ratio, OR = 1.105, 95 % confidence interval, CI = 1.025-1.190) than their non-exposed counterparts. Further analysis showed that the odds ratio of Ahlzheimer's disease was 1.07 (95 % CI = 0.962-1.196) in men and 1.132 (95 % CI = 1.022-1.254) in women. Conclusions Women who were exposed to amalgam fillings were 1.132 times more likely to have Alzheimer’s disease than were their non-exposed counterparts.
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Affiliation(s)
- Yi-Hua Sun
- School of Dentistry, Chung Shan Medical University, Taichung City, 40201, Taiwan.
| | - Oswald Ndi Nfor
- Department of Public Health and Institute of Public Health, Chung Shan Medical University, No. 110 Sec. 1 Jianguo N. Road, Taichung City, 40201, Taiwan.
| | - Jing-Yang Huang
- Department of Public Health and Institute of Public Health, Chung Shan Medical University, No. 110 Sec. 1 Jianguo N. Road, Taichung City, 40201, Taiwan.
| | - Yung-Po Liaw
- Department of Public Health and Institute of Public Health, Chung Shan Medical University, No. 110 Sec. 1 Jianguo N. Road, Taichung City, 40201, Taiwan. .,Department of Family and Community Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan.
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Cross-validation of a Shortened Battery for the Assessment of Dysexecutive Disorders in Alzheimer Disease. Alzheimer Dis Assoc Disord 2015; 30:140-4. [PMID: 26485496 DOI: 10.1097/wad.0000000000000112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The frequency of executive disorders in mild-to-moderate Alzheimer disease (AD) has been demonstrated by the application of a comprehensive battery. The present study analyzed data from 2 recent multicenter studies based on the same executive battery. The objective was to derive a shortened battery by using the GREFEX population as a training dataset and by cross-validating the results in the REFLEX population. A total of 102 AD patients of the GREFEX study (MMSE=23.2±2.9) and 72 patients of the REFLEX study (MMSE=20.8±3.5) were included. Tests were selected and receiver operating characteristic curves were generated relative to the performance of 780 controls from the GREFEX study. Stepwise logistic regression identified 3 cognitive tests (Six Elements Task, categorical fluency and Trail Making Test B error) and behavioral disorders globally referred as global hypoactivity (P=0.0001, all). This shortened battery was as accurate as the entire GREFEX battery in diagnosing dysexecutive disorders in both training group and the validation group. Bootstrap procedure confirmed the stability of AUC. A shortened battery based on 3 cognitive tests and 3 behavioral domains provides a high diagnosis accuracy of executive disorders in mild-to-moderate AD.
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Marques IB, Tábuas-Pereira M, Milheiro M, Santana I. Biparietal variant of Alzheimer's disease: a rare presentation of a common disease. BMJ Case Rep 2015; 2015:bcr-2014-207011. [PMID: 25564588 DOI: 10.1136/bcr-2014-207011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Alzheimer's disease (AD) is a clinically heterogeneous disease that may have atypical presentations with focal cortical syndromes and relatively preserved episodic memory. The posterior variant of AD has two subtypes: occipitotemporal, presenting with visuoperceptive impairment, and biparietal, presenting with visuospatial dysfunction and apraxia. We report a case of a 51-year-old woman with progressive limb apraxia and choreiform movements. Her neuropsychological evaluation was compatible with dementia, and revealed ideomotor and ideational limb apraxia, severe visuoconstructive ability impairment, dyscalculia and posterior aphasia. Workup excluded metabolic, infectious, inflammatory or neoplastic causes, and hereditary conditions as Huntington's disease and familial AD. Cerebrospinal fluid biomarkers revealed β-amyloid reduction and τ protein increase. Brain imaging showed marked biparietal atrophy and hypoperfusion, and widespread cortical β-amyloid deposition. Biparietal variant of AD was diagnosed and acetylcholinesterase inhibitor treatment induced clinical stabilisation. AD may present with atypical features and a high clinical suspicion is necessary for an early diagnosis.
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Affiliation(s)
- Inês B Marques
- Department of Neurology, Coimbra University Hospital, Coimbra, Portugal
| | | | | | - Isabel Santana
- Department of Neurology, Coimbra University Hospital, Coimbra, Portugal
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29
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Pfefferbaum A, Rogosa DA, Rosenbloom MJ, Chu W, Sassoon SA, Kemper CA, Deresinski S, Rohlfing T, Zahr NM, Sullivan EV. Accelerated aging of selective brain structures in human immunodeficiency virus infection: a controlled, longitudinal magnetic resonance imaging study. Neurobiol Aging 2014; 35:1755-68. [PMID: 24508219 PMCID: PMC3980003 DOI: 10.1016/j.neurobiolaging.2014.01.008] [Citation(s) in RCA: 95] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 12/17/2013] [Accepted: 01/08/2014] [Indexed: 12/20/2022]
Abstract
Advances in treatment have transformed human immunodeficiency virus (HIV) infection from an inexorable march to severe morbidity and premature death to a manageable chronic condition, often marked by good health. Thus, infected individuals are living long enough that there is a potential for interaction with normal senescence effects on various organ systems, including the brain. To examine this interaction, the brains of 51 individuals with HIV infection and 65 uninfected controls were studied using 351 magnetic resonance imaging and a battery of neuropsychological tests collected 2 or more times over follow-up periods ranging from 6 months to 8 years. Brain tissue regions of interest showed expected age-related decrease in volume; cerebrospinal fluid-filled spaces showed increase in volume for both groups. Although HIV-infected individuals were in good general health, and free of clinically-detectable dementia, several brain regions supporting higher-order cognition and integration of functions showed acceleration of the normal aging trajectory, including neocortex, which extended from the frontal and temporal poles to the parietal lobe, and the thalamus. Beyond an anticipated increase in lateral ventricle and Sylvian fissure volumes and decrease in tissue volumes (specifically, the frontal and sensorimotor neocortices, thalamus, and hippocampus) with longer duration of illness, most regions also showed accelerated disease progression. This accelerated loss of cortical tissue may represent a risk factor for premature cognitive and motor compromise if not dementia. On a more promising note, HIV-infected patients with increasing CD4 counts exhibited slower expansion of Sylvian fissure volume and slower declines of frontal and temporoparietal cortices, insula, and hippocampus tissue volumes. Thus, attenuated shrinkage of these brain regions, likely with adequate pharmacologic treatment and control of further infection, has the potential of abating decline in associated higher-order functions, notably, explicit memory, executive functions, self-regulation, and visuospatial abilities.
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Affiliation(s)
- Adolf Pfefferbaum
- Biosciences Division, Neuroscience Program, SRI International, Menlo Park, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - David A Rogosa
- Department of Education, Stanford University, Stanford, CA, USA; Department of Biostatistics, Stanford University, Stanford, CA, USA
| | - Margaret J Rosenbloom
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Weiwei Chu
- Biosciences Division, Neuroscience Program, SRI International, Menlo Park, CA, USA
| | - Stephanie A Sassoon
- Biosciences Division, Neuroscience Program, SRI International, Menlo Park, CA, USA
| | - Carol A Kemper
- Division of Infectious Diseases, Santa Clara Valley Medical Center, Santa Clara, CA, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Stanley Deresinski
- Division of Infectious Diseases, Santa Clara Valley Medical Center, Santa Clara, CA, USA; Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Torsten Rohlfing
- Biosciences Division, Neuroscience Program, SRI International, Menlo Park, CA, USA
| | - Natalie M Zahr
- Biosciences Division, Neuroscience Program, SRI International, Menlo Park, CA, USA; Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Edith V Sullivan
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA.
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Uittenhove K, Burger L, Taconnat L, Lemaire P. Sequential difficulty effects during execution of memory strategies in young and older adults. Memory 2014; 23:806-16. [DOI: 10.1080/09658211.2014.928730] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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32
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Executive functions in clinical and preclinical Alzheimer's disease. Rev Neurol (Paris) 2013; 169:695-708. [DOI: 10.1016/j.neurol.2013.07.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 07/23/2013] [Accepted: 07/23/2013] [Indexed: 01/18/2023]
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Daulatzai MA. Neurotoxic Saboteurs: Straws that Break the Hippo’s (Hippocampus) Back Drive Cognitive Impairment and Alzheimer’s Disease. Neurotox Res 2013; 24:407-59. [DOI: 10.1007/s12640-013-9407-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 06/06/2013] [Accepted: 06/17/2013] [Indexed: 12/29/2022]
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Spironelli C, Bergamaschi S, Mondini S, Villani D, Angrilli A. Functional plasticity in Alzheimer's disease: Effect of cognitive training on language-related ERP components. Neuropsychologia 2013; 51:1638-48. [DOI: 10.1016/j.neuropsychologia.2013.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 02/14/2013] [Accepted: 05/07/2013] [Indexed: 10/26/2022]
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Abstract
In this article, cognitive measures in the screening of individuals at risk for Alzheimer disease (AD) are reviewed. Use of cognitive tasks in identifying clinical cases of AD is considered, as well as methods for detecting those in the prodromal stages of the disease, including cognitive screening instruments. Traditional assessments, such as the mini-mental state examination, as well as contemporary computerized screening instruments, are examined. Areas of cognition for investigation in the detection of prodromal AD are recommended. The prospects for general cognitive screening are reviewed, and more engaging technologies to tests individuals at risk for developing AD are recommended.
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Affiliation(s)
- John Harrison
- Department of Medicine, Imperial College, London & Metis Cognition Ltd, Park House, Kilmington Common, Wiltshire, UK.
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Henry MS, Passmore AP, Todd S, McGuinness B, Craig D, Johnston JA. The development of effective biomarkers for Alzheimer's disease: a review. Int J Geriatr Psychiatry 2013; 28:331-40. [PMID: 22674539 DOI: 10.1002/gps.3829] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 04/11/2012] [Indexed: 12/29/2022]
Abstract
OBJECTIVE There is a widely recognised need to develop effective Alzheimer's disease (AD) biomarkers to aid the development of disease-modifying treatments, to facilitate early diagnosis and to improve clinical care. This overview aims to summarise the utility of key neuroimaging and cerebrospinal fluid (CSF) biomarkers for AD, before focusing on the latest efforts to identify informative blood biomarkers. DESIGN A literature search was performed using PubMed up to September 2011 for reviews and primary research studies of neuroimaging (magnetic resonance imaging, magnetic resonance spectroscopy, positron emission tomography and amyloid imaging), CSF and blood-based (plasma, serum and platelet) biomarkers in AD and mild cognitive impairment. Citations within individual articles were examined to identify additional studies relevant to this review. RESULTS Evidence of AD biomarker potential was available for imaging techniques reflecting amyloid burden and neurodegeneration. Several CSF measures are promising, including 42 amino acid β-amyloid peptide (Aβ42 ); total tau (T-tau) protein, reflecting axonal damage; and phosphorylated tau (P-tau), reflecting neurofibrillary tangle pathology. Studies of plasma Aβ have produced inferior diagnostic discrimination. Alternative plasma and platelet measures are described, which represent potential avenues for future research. CONCLUSIONS Several imaging and CSF markers demonstrate utility in predicting AD progression and determining aetiology. These require standardisation before forming core elements of diagnostic criteria. The enormous potential available for identifying a minimally-invasive, easily-accessible blood measure as an effective AD biomarker currently remains unfulfilled.
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Affiliation(s)
- Mark S Henry
- Centre for Public Health, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
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Structural and functional bases of visuospatial associative memory in older adults. Neurobiol Aging 2013; 34:961-72. [DOI: 10.1016/j.neurobiolaging.2012.07.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 06/29/2012] [Accepted: 07/11/2012] [Indexed: 11/22/2022]
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Abstract
Late-onset Alzheimer's disease (AD) is the most prevalent cause of dementia among older adults, yet more than a century of research has not determined why this disease develops. One prevailing hypothesis is that late-onset AD is caused by infectious pathogens, an idea widely studied in both humans and experimental animal models. This review examines the infectious AD etiology hypothesis and summarizes existing evidence associating infectious agents with AD in humans. The various mechanisms through which different clinical and subclinical infections could cause or promote the progression of AD are considered, as is the concordance between putative infectious agents and the epidemiology of AD. We searched the PubMed, Web of Science, and EBSCO databases for research articles pertaining to infections and AD and systematically reviewed the evidence linking specific infectious pathogens to AD. The evidence compiled from the literature linking AD to an infectious cause is inconclusive, but the amount of evidence suggestive of an association is too substantial to ignore. Epidemiologic, clinical, and basic science studies that could improve on current understanding of the associations between AD and infections and possibly uncover ways to control this highly prevalent and debilitating disease are suggested.
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Affiliation(s)
| | - Robert Wallace
- Correspondence to Dr. Robert Wallace, Department of Epidemiology, College of Public Health, The University of Iowa, 105 River St. Iowa City, IA 52242 (e-mail: )
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Van Dam NT, Sano M, Mitsis EM, Grossman HT, Gu X, Park Y, Hof PR, Fan J. Functional neural correlates of attentional deficits in amnestic mild cognitive impairment. PLoS One 2013; 8:e54035. [PMID: 23326568 PMCID: PMC3543395 DOI: 10.1371/journal.pone.0054035] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 12/07/2012] [Indexed: 11/29/2022] Open
Abstract
Although amnestic mild cognitive impairment (aMCI; often considered a prodromal phase of Alzheimer's disease, AD) is most recognized by its implications for decline in memory function, research suggests that deficits in attention are present early in aMCI and may be predictive of progression to AD. The present study used functional magnetic resonance imaging to examine differences in the brain during the attention network test between 8 individuals with aMCI and 8 neurologically healthy, demographically matched controls. While there were no significant behavioral differences between groups for the alerting and orienting functions, patients with aMCI showed more activity in neural regions typically associated with the networks subserving these functions (e.g., temporoparietal junction and posterior parietal regions, respectively). More importantly, there were both behavioral (i.e., greater conflict effect) and corresponding neural deficits in executive control (e.g., less activation in the prefrontal and anterior cingulate cortices). Although based on a small number of patients, our findings suggest that deficits of attention, especially the executive control of attention, may significantly contribute to the behavioral and cognitive deficits of aMCI.
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Affiliation(s)
- Nicholas T. Van Dam
- Department of Psychology, Queens College, City University of New York, Flushing, New York, United States of America
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Mary Sano
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
- Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Effie M. Mitsis
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
- Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Hillel T. Grossman
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neurology, Mount Sinai School of Medicine, New York, New York, United States of America
- Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Xiaosi Gu
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Yunsoo Park
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Patrick R. Hof
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
- Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York, United States of America
- Friedman Brain Institute, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Jin Fan
- Department of Psychology, Queens College, City University of New York, Flushing, New York, United States of America
- Department of Psychiatry, Mount Sinai School of Medicine, New York, New York, United States of America
- Department of Neuroscience, Mount Sinai School of Medicine, New York, New York, United States of America
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Li S, Okonkwo O, Albert M, Wang MC. Variation in Variables that Predict Progression from MCI to AD Dementia over Duration of Follow-up. ACTA ACUST UNITED AC 2013; 2:12-28. [PMID: 24524014 DOI: 10.7726/ajad.2013.1002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The purpose of this paper is to investigate the relative utility of using neuroimaging, genetic, cerebrospinal fluid (CSF), and cognitive measures to predict progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD) dementia over a follow-up period. The studied subjects were 139 persons with MCI enrolled in the Alzheimer's Disease Neuroimaging Initiative. Predictors of progression to AD included brain volume, ventricular volume, hippocampal volume, APOE ε4 two alleles, Aβ42, p-tau181, p-tau181/Aβ42, memory, language, and executive function. We employ a combination of Cox regression analyses and time-dependent receiver operating characteristic (ROC) methods to assess the prognostic utility and performance stability of candidate biomarkers. In a demographic-adjusted multivariable Cox model, seven measures- brain volume, hippocampal volume, ventricular volume, APOE ε4 two alleles, Aβ42, Memory composite, Executive function composite - predicted progression to AD. Time-dependent ROC revealed that this multivariable model had an area under the curve of 0.832, 0.788, 0.794, and 0.757 at 12, 18, 24, and 36 months respectively. Supplemental Cox models with time of origin set differentially at 12, 18, 24 and 36 months showed that six measures were significant predictors at 12 months whereas only memory and executive function predicted progression to AD at 18 and 24 months. The authors concluded that baseline volumetric MRI and cognitive measures selectively predict progression from MCI to AD, with cognitive measures remaining predictive even late in the follow-up period. These findings may inform case selection for AD clinical trials.
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Affiliation(s)
- Shanshan Li
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Ozioma Okonkwo
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
| | - Marilyn Albert
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Mei-Cheng Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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Behavioral effects of Rho GTPase modulation in a model of Alzheimer's disease. Behav Brain Res 2012; 237:223-9. [PMID: 23026376 DOI: 10.1016/j.bbr.2012.09.043] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 09/18/2012] [Accepted: 09/23/2012] [Indexed: 12/19/2022]
Abstract
Small GTPases of the Rho family, including Rho, Rac and CDC42 subfamilies, play key role in neural connectivity and cognition. The pharmacological modulation of these regulatory proteins is associated with enhancement of learning and memory. We sought to determine whether the modulation of cerebral Rho GTPases may correct behavioral disturbances in a mouse model of Alzheimer's disease (AD). TgCRND8 mice show early-onset Abeta amyloid deposits associated with deficits in several cognitive tasks. We report that four-month old TgCRND8 mice display (a) increased locomotor activity in an open field, (b) mild deficits in the learning of a fixed platform position in a water maze task. More markedly, after displacement of the escape platform, TgCRND8 mice exhibit impairment in the learning of the novel position (reversal learning), as they perseverate searching in the familiar position. The administration of the Rho GTPase activator Cytotoxic Necrotizing Factor 1 (CNF1, 1.0 fmol kg(-1) intracerebroventricularly) reduces locomotor hyperactivity and corrects the deficits in reversal learning, thus re-establishing normal behavioral plasticity. We conclude that the pharmacological modulation of Rho GTPase signaling might be beneficial for the treatment of AD. Reversal learning in TgCRND8 mice may represent a convenient pre-clinical assay for the efficacy of therapeutic interventions in AD.
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Romberg C, Horner AE, Bussey TJ, Saksida LM. A touch screen-automated cognitive test battery reveals impaired attention, memory abnormalities, and increased response inhibition in the TgCRND8 mouse model of Alzheimer's disease. Neurobiol Aging 2012; 34:731-44. [PMID: 22959727 PMCID: PMC3532594 DOI: 10.1016/j.neurobiolaging.2012.08.006] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 06/21/2012] [Accepted: 08/09/2012] [Indexed: 12/12/2022]
Abstract
Transgenic mouse models of Alzheimer's disease (AD) with abundant β-amyloid develop memory impairments. However, multiple nonmnemonic cognitive domains such as attention and executive control are also compromised early in AD individuals, but have not been routinely assessed in animal models. Here, we assessed the cognitive abilities of TgCRND8 mice—a widely used model of β-amyloid pathology—with a touch screen-based automated test battery. The test battery comprises highly translatable tests of multiple cognitive constructs impaired in human AD, such as memory, attention, and response control, as well as appropriate control tasks. We found that familial AD mutations affect not only memory, but also cause significant alterations of sustained attention and behavioral flexibility. Because changes in attention and response inhibition may affect performance on tests of other cognitive abilities including memory, our findings have important consequences for the assessment of disease mechanisms and therapeutics in animal models of AD. A more comprehensive phenotyping with specialized, multicomponent cognitive test batteries for mice might significantly advance translation from preclinical mouse studies to the clinic.
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Affiliation(s)
- Carola Romberg
- Department of Experimental Psychology, University of Cambridge, Cambridge, UK.
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Abstract
The availability of neuroimaging technology has spurred a marked increase in the human cognitive neuroscience literature, including the study of cognitive ageing. Although there is a growing consensus that the ageing brain retains considerable plasticity of function, currently measured primarily by means of functional MRI, it is less clear how age differences in brain activity relate to cognitive performance. The field is also hampered by the complexity of the ageing process itself and the large number of factors that are influenced by age. In this Review, current trends and unresolved issues in the cognitive neuroscience of ageing are discussed.
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Affiliation(s)
- Cheryl Grady
- The Rotman Research Institute at Baycrest, 3560 Bathurst Street, Toronto, Ontario M6A 2E1, Canada.
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Cerebrospinal fluid markers for Alzheimer's disease in a cognitively healthy cohort of young and old adults. Alzheimers Dement 2012; 8:520-7. [PMID: 22677492 DOI: 10.1016/j.jalz.2011.10.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 09/15/2011] [Accepted: 10/10/2011] [Indexed: 11/23/2022]
Abstract
BACKGROUND Low amyloid β42 (Aβ42) and high total tau and phosphorylated tau (p-tau) concentrations in the cerebrospinal fluid (CSF) are biomarkers of Alzheimer's disease (AD), reflecting brain deposition of amyloid plaques and tangles. Age and apolipoprotein E allele E4 are two strong risk factors for AD, but few data are still available on their effect on CSF markers in normal aging. OBJECTIVE To study the effect of age on CSF Aβ42, total tau, and p-tau levels in a well-characterized group of cognitively normal subjects. METHODS CSF Aβ42 levels of 81 subjects (27% female, 53 ± 15.3 years, range: 21-88) were determined with sandwich enzyme-linked immunosorbent assay; of these, total tau and p-tau levels were measured in 61 (75%) and 42 (52%) cases, respectively. A linear regression analysis between age and CSF markers was carried out on the whole sample and separately in apolipoprotein E allele ɛ4 carriers and noncarriers. RESULTS The median levels of all markers were significantly different between young (<65 years) and old (≥65 years) subjects (Aβ42: P = .03; tau: P = .02; p-tau: P = .002; tau/Aβ42: P = .004; p-tau/Aβ42: P = .03). The association of marker levels with age was confirmed in linear regression models, where a positive relationship with age was observed for total tau (B = 2.3; 95% confidence interval [CI]: 0.89 to 3.7; P = .002), p-tau (B = 0.5; 95% CI: 0.1 to 0.9; P = .02), and tau/Aβ42 ratio (B = 0.006; 95% CI: 0.002 to 0.01; P = .002). No subjects showed abnormal tau, whereas 19% showed abnormal CSF Aβ42 concentrations. CONCLUSION In cognitively normal subjects, the concentrations of CSF biomarkers of AD are associated with age. Further longitudinal studies could clarify whether Aβ42 low levels represent a preclinical AD biomarker.
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Abstract
Neuropsychological assessment has featured prominently over the past 30 years in the characterization of dementia associated with Alzheimer disease (AD). Clinical neuropsychological methods have identified the earliest, most definitive cognitive and behavioral symptoms of illness, contributing to the identification, staging, and tracking of disease. With increasing public awareness of dementia, disease detection has moved to earlier stages of illness, at a time when deficits are both behaviorally and pathologically selective. For reasons that are not well understood, early AD pathology frequently targets large-scale neuroanatomical networks for episodic memory before other networks that subserve language, attention, executive functions, and visuospatial abilities. This chapter reviews the pathognomonic neuropsychological features of AD dementia and how these differ from "normal," age-related cognitive decline and from other neurodegenerative diseases that cause dementia, including cortical Lewy body disease, frontotemporal lobar degeneration, and cerebrovascular disease.
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Affiliation(s)
- Sandra Weintraub
- Cognitive Neurology and Alzheimer's Disease Center (CNADC), Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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46
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Dual task abilities as a possible preclinical marker of Alzheimer's disease in carriers of the E280A presenilin-1 mutation. J Int Neuropsychol Soc 2012; 18:234-41. [PMID: 22133015 DOI: 10.1017/s1355617711001561] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Previous dual task studies have demonstrated that patients with sporadic Alzheimer's disease (AD) are impaired in their ability to perform two tasks simultaneously compared with healthy controls, despite being able to successfully perform the tasks alone relatively well. Yet, it remains unclear what the earliest clinical manifestation of this dual task coordination deficit is. This study examined dual task abilities in individuals who are at risk of early-onset familial AD due to an E280A presenilin-1 mutation. Thirty-nine carriers of the gene mutation who did not meet the criteria for AD and 29 non-carrier healthy controls were asked to perform digit recall accompanied by a secondary tracking task. Individuals who were carriers of the genetic mutation demonstrated significantly higher dual task costs than healthy non-carriers. Dual task performance was found to be more sensitive to this very early stage of FAD than episodic memory measures. The findings support the notion that a deficit in the coordination mechanism of the central executive may be a pre-clinical marker for the early detection of AD due to the E280A presenilin-1 gene mutation.
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Abstract
The clinical hallmark of Alzheimer's disease (AD) is a gradual decline in cognitive function. For the majority of patients the initial symptom is an impairment in episodic memory, i.e., the ability to learn and retain new information. This is followed by impairments in other cognitive domains (e.g., executive function, language, spatial ability). This impairment in episodic memory is evident among individuals with mild cognitive impairment (MCI) and can be used to predict likelihood of progression to dementia, particularly in association with AD biomarkers. Additionally, cognitively normal individuals who are likely to progress to mild impairment tend to perform more poorly on tests of episodic memory than do those who remain stable. This cognitive presentation is consistent with the pathology of AD, showing neuronal loss in medial temporal lobe structures essential for normal memory. Similarly, there are correlations between magnetic resonance imaging (MRI) measures of medial temporal lobe structures and memory performance among individuals with mild cognitive impairment. There are recent reports that amyloid accumulation may also be associated with memory performance in cognitively normal individuals.
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Affiliation(s)
- Marilyn S Albert
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Pritchard SM, Dolan PJ, Vitkus A, Johnson GVW. The toxicity of tau in Alzheimer disease: turnover, targets and potential therapeutics. J Cell Mol Med 2011; 15:1621-35. [PMID: 21348938 PMCID: PMC4373356 DOI: 10.1111/j.1582-4934.2011.01273.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 02/08/2011] [Indexed: 11/28/2022] Open
Abstract
It has been almost 25 years since the initial discovery that tau was the primary component of the neurofibrillary tangles (NFTs) in Alzheimer disease (AD) brain. Although AD is defined by both β-amyloid (Aβ) pathology (Aβ plaques) and tau pathology (NFTs), whether or not tau played a critical role in disease pathogenesis was a subject of discussion for many years. However, given the increasing evidence that pathological forms of tau can compromise neuronal function and that tau is likely an important mediator of Aβ toxicity, there is a growing awareness that tau is a central player in AD pathogenesis. In this review we begin with a brief history of tau, then provide an overview of pathological forms of tau, followed by a discussion of the differential degradation of tau by either the proteasome or autophagy and possible mechanisms by which pathological forms of tau may exert their toxicity. We conclude by discussing possible avenues for therapeutic intervention based on these emerging themes of tau's role in AD.
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Affiliation(s)
- Susanne M Pritchard
- Gail V.W. JOHNSON, Ph.D., Department of Anesthesiology, 601 Elmwood Ave., Box 604, Rm. 4–6314, University of Rochester, Rochester, NY 14642, USA. Tel.: 585-276-3740 Fax: 585-276-2418 E-mail:
| | | | - Alisa Vitkus
- Department of Anesthesiology and the Interdepartmental Graduate Program in Neuroscience, University of RochesterRochester, NY, USA
| | - Gail VW Johnson
- Department of Anesthesiology and the Interdepartmental Graduate Program in Neuroscience, University of RochesterRochester, NY, USA
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Abstract
Brain regions and their highly neuroplastic long axonal connections that expanded rapidly during hominid evolution are preferentially affected by Alzheimer disease. There is no natural animal model with full disease pathology (neurofibrillary tangles and neuritic amyloid plaques of a severity seen in Alzheimer's disease brains). Biomarkers such as reduced glucose metabolism in association neocortex, defects in long white matter tracts, RNA neurochemical changes, and high CSF levels of total and phosphorylated tau protein, which are helpful to identify MCI and preclinical Alzheimer disease patients, may also provide insights into what brain changes led to this disease being introduced during hominid evolution.
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Hutchison KA, Balota DA, Duchek JM, Ducheck JM. The utility of Stroop task switching as a marker for early-stage Alzheimer's disease. Psychol Aging 2011; 25:545-59. [PMID: 20853964 DOI: 10.1037/a0018498] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Past studies have suggested attentional control tasks such as the Stroop task and the task-switching paradigm may be sensitive for the early detection of dementia of the Alzheimer's type (DAT). The authors of the current study combined these tasks to create a Stroop switching task. Performance was compared across young adults, older adults, and individuals diagnosed with very mild dementia. Results indicated that this task strongly discriminated individuals with healthy aging from those with early-stage DAT. In a logistic regression analysis, incongruent error rates from the Stroop switching task discriminated healthy aging from DAT better than any of the other 18 cognitive tasks given in a psychometric battery.
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Affiliation(s)
- Keith A Hutchison
- Department of Psychology, Montana State University, Bozeman, MT 59717-3340, USA.
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