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Wharton SB, Simpson JE, Ince PG, Richardson CD, Merrick R, Matthews FE, Brayne C. Insights into the pathological basis of dementia from population-based neuropathology studies. Neuropathol Appl Neurobiol 2023; 49:e12923. [PMID: 37462105 PMCID: PMC10946587 DOI: 10.1111/nan.12923] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/13/2023] [Accepted: 06/29/2023] [Indexed: 08/17/2023]
Abstract
The epidemiological neuropathology perspective of population and community-based studies allows unbiased assessment of the prevalence of various pathologies and their relationships to late-life dementia. In addition, this approach provides complementary insights to conventional case-control studies, which tend to be more representative of a younger clinical cohort. The Cognitive Function and Ageing Study (CFAS) is a longitudinal study of cognitive impairment and frailty in the general United Kingdom population. In this review, we provide an overview of the major findings from CFAS, alongside other studies, which have demonstrated a high prevalence of pathology in the ageing brain, particularly Alzheimer's disease neuropathological change and vascular pathology. Increasing burdens of these pathologies are the major correlates of dementia, especially neurofibrillary tangles, but there is substantial overlap in pathology between those with and without dementia, particularly at intermediate burdens of pathology and also at the oldest ages. Furthermore, additional pathologies such as limbic-predominant age-related TDP-43 encephalopathy, ageing-related tau astrogliopathy and primary age-related tauopathies contribute to late-life dementia. Findings from ageing population-representative studies have implications for the understanding of dementia pathology in the community. The high prevalence of pathology and variable relationship to dementia status has implications for disease definition and indicate a role for modulating factors on cognitive outcome. The complexity of late-life dementia, with mixed pathologies, indicates a need for a better understanding of these processes across the life-course to direct the best research for reducing risk in later life of avoidable clinical dementia syndromes.
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Affiliation(s)
- Stephen B. Wharton
- Sheffield Institute for Translational NeuroscienceUniversity of SheffieldSheffieldUK
| | - Julie E. Simpson
- Sheffield Institute for Translational NeuroscienceUniversity of SheffieldSheffieldUK
| | - Paul G. Ince
- Sheffield Institute for Translational NeuroscienceUniversity of SheffieldSheffieldUK
| | | | - Richard Merrick
- Cambridge Public Health, School of Clinical MedicineUniversity of CambridgeSheffieldUK
| | | | - Carol Brayne
- Cambridge Public Health, School of Clinical MedicineUniversity of CambridgeSheffieldUK
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Berres M, Monsch AU, Spiegel R. Using historical data to facilitate clinical prevention trials in Alzheimer disease? An analysis of longitudinal MCI (mild cognitive impairment) data sets. Alzheimers Res Ther 2021; 13:97. [PMID: 33962665 PMCID: PMC8106156 DOI: 10.1186/s13195-021-00832-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 04/19/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The Placebo Group Simulation Approach (PGSA) aims at partially replacing randomized placebo-controlled trials (RPCTs), making use of data from historical control groups in order to decrease the needed number of study participants exposed to lengthy placebo treatment. PGSA algorithms to create virtual control groups were originally derived from mild cognitive impairment (MCI) data of the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. To produce more generalizable algorithms, we aimed to compile five different MCI databases in a heuristic manner to create a "standard control algorithm" for use in future clinical trials. METHODS We compared data from two North American cohort studies (n=395 and 4328, respectively), one company-sponsored international clinical drug trial (n=831) and two convenience patient samples, one from Germany (n=726), and one from Switzerland (n=1558). RESULTS Despite differences between the five MCI samples regarding inclusion and exclusion criteria, their baseline demographic and cognitive performance data varied less than expected. However, the five samples differed markedly with regard to their subsequent cognitive performance and clinical development: (1) MCI patients from the drug trial did not deteriorate on verbal fluency over 3 years, whereas patients in the other samples did; (2) relatively few patients from the drug trial progressed from MCI to dementia (about 10% after 4 years), in contrast to the other four samples with progression rates over 30%. CONCLUSION Conventional MCI criteria were insufficient to allow for the creation of well-defined and internationally comparable samples of MCI patients. More recently published criteria for MCI or "MCI due to AD" are unlikely to remedy this situation. The Alzheimer scientific community needs to agree on a standard set of neuropsychological tests including appropriate selection criteria to make MCI a scientifically more useful concept. Patient data from different sources would then be comparable, and the scientific merits of algorithm-based study designs such as the PGSA could be properly assessed.
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Affiliation(s)
- Manfred Berres
- University of Applied Sciences Koblenz, Koblenz, Germany
- University Department of Geriatric Medicine FELIX PLATTER, Basel, Switzerland
| | - Andreas U. Monsch
- University Department of Geriatric Medicine FELIX PLATTER, Basel, Switzerland
| | - René Spiegel
- University Department of Geriatric Medicine FELIX PLATTER, Basel, Switzerland
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Waller R, Narramore R, Simpson JE, Heath PR, Verma N, Tinsley M, Barnes JR, Haris HT, Henderson FE, Matthews FE, Richardson CD, Brayne C, Ince PG, Kalaria RN, Wharton SB. Heterogeneity of cellular inflammatory responses in ageing white matter and relationship to Alzheimer's and small vessel disease pathologies. Brain Pathol 2021; 31:e12928. [PMID: 33336479 PMCID: PMC8412112 DOI: 10.1111/bpa.12928] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022] Open
Abstract
White matter lesions (WML) are common in the ageing brain, often arising in a field effect of diffuse white matter abnormality. Although WML are associated with cerebral small vessel disease (SVD) and Alzheimer’s disease (AD), their cause and pathogenesis remain unclear. The current study tested the hypothesis that different patterns of neuroinflammation are associated with SVD compared to AD neuropathology by assessing the immunoreactive profile of the microglial (CD68, IBA1 and MHC‐II) and astrocyte (GFAP) markers in ageing parietal white matter (PARWM) obtained from the Cognitive Function and Ageing Study (CFAS), an ageing population‐representative neuropathology cohort. Glial responses varied extensively across the PARWM with microglial markers significantly higher in the subventricular region compared to either the middle‐zone (CD68 p = 0.028, IBA1 p < 0.001, MHC‐II p < 0.001) or subcortical region (CD68 p = 0.002, IBA1 p < 0.001, MHC‐II p < 0.001). Clasmatodendritic (CD) GFAP+ astrocytes significantly increased from the subcortical to the subventricular region (p < 0.001), whilst GFAP+ stellate astrocytes significantly decreased (p < 0.001). Cellular reactions could be grouped into two distinct patterns: an immune response associated with MHC‐II/IBA1 expression and CD astrocytes; and a more innate response characterised by CD68 expression associated with WML. White matter neuroinflammation showed weak relationships to the measures of SVD, but not to the measures of AD neuropathology. In conclusion, glial responses vary extensively across the PARWM with diverse patterns of white matter neuroinflammation. Although these findings support a role for vascular factors in the pathogenesis of age‐related white matter neuroinflammation, additional factors other than SVD and AD pathology may drive this. Understanding the heterogeneity in white matter neuroinflammation will be important for the therapeutic targeting of age‐associated white matter damage.
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Affiliation(s)
- Rachel Waller
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Ruth Narramore
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Julie E Simpson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Nikita Verma
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Megan Tinsley
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Jordan R Barnes
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Hanna T Haris
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Frances E Henderson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Fiona E Matthews
- Translational and Clinical Research Institute, University of Newcastle, Newcastle upon Tyne, UK
| | - Connor D Richardson
- Translational and Clinical Research Institute, University of Newcastle, Newcastle upon Tyne, UK
| | - Carol Brayne
- Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Paul G Ince
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Raj N Kalaria
- Translational and Clinical Research Institute, University of Newcastle, Newcastle upon Tyne, UK
| | - Stephen B Wharton
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
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Blazhenets G, Frings L, Ma Y, Sörensen A, Eidelberg D, Wiltfang J, Meyer PT. Validation of the Alzheimer Disease Dementia Conversion-Related Pattern as an ATN Biomarker of Neurodegeneration. Neurology 2021; 96:e1358-e1368. [PMID: 33408150 DOI: 10.1212/wnl.0000000000011521] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 11/09/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether the Alzheimer disease (AD) dementia conversion-related pattern (ADCRP) on [18F]FDG PET can serve as a valid predictor for the development of AD dementia, the individual expression of the ADCRP (subject score) and its prognostic value were examined in patients with mild cognitive impairment (MCI) and biologically defined AD. METHODS A total of 269 patients with available [18F]FDG PET, [18F]AV-45 PET, phosphorylated and total tau in CSF, and neurofilament light chain in plasma were included. Following the AT(N) classification scheme, where AD is defined biologically by in vivo biomarkers of β-amyloid (Aβ) deposition ("A") and pathologic tau ("T"), patients were categorized to the A-T-, A+T-, A+T+ (AD), and A-T+ groups. RESULTS The mean subject score of the ADCRP was significantly higher in the A+T+ group compared to each of the other group (all p < 0.05) but was similar among the latter (all p > 0.1). Within the A+T+ group, the subject score of ADCRP was a significant predictor of conversion to dementia (hazard ratio, 2.02 per z score increase; p < 0.001), with higher predictive value than of alternative biomarkers of neurodegeneration (total tau and neurofilament light chain). Stratification of A+T+ patients by the subject score of ADCRP yielded well-separated groups of high, medium, and low conversion risks. CONCLUSIONS The ADCRP is a valuable biomarker of neurodegeneration in patients with MCI and biologically defined AD. It shows great potential for stratifying the risk and estimating the time to conversion to dementia in patients with MCI and underlying AD (A+T+). CLASSIFICATION OF EVIDENCE This study provides Class I evidence that [18F]FDG PET predicts the development of AD dementia in individuals with MCI and underlying AD as defined by the AT(N) framework.
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Affiliation(s)
- Ganna Blazhenets
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany.
| | - Lars Frings
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany
| | - Yilong Ma
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany
| | - Arnd Sörensen
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany
| | - David Eidelberg
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany
| | - Jens Wiltfang
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany
| | - Philipp T Meyer
- From the Department of Nuclear Medicine (G.B., L.F., A.S., P.T.M.), Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg; Center for Neurosciences (Y.M., D.E.), Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY; and Department of Psychiatry and Psychotherapy (J.W.), University Medical Center, Georg-August-University, Göttingen, Germany
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Wilson RS, Yang J, Yu L, Leurgans SE, Capuano AW, Schneider JA, Bennett DA, Boyle PA. Postmortem neurodegenerative markers and trajectories of decline in cognitive systems. Neurology 2019; 92:e831-e840. [PMID: 30674595 PMCID: PMC6396970 DOI: 10.1212/wnl.0000000000006949] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE To assess whether neurodegenerative pathologies are differentially related to trajectories of change in different cognitive abilities. METHODS At annual intervals for up to 21 years, 915 older participants in a longitudinal clinical-pathologic cohort study completed a battery of 15 tests from which previously established composite measures of episodic memory, semantic memory, working memory, and perceptual speed were derived. At death, they underwent a neuropathologic examination to quantify Alzheimer disease pathology, Lewy bodies, transactive response DNA-binding protein 43 (TDP-43) pathology, and hippocampal sclerosis plus multiple markers of cerebrovascular disease. Time-varying effect models were used to assess change over time in the relation of neuropathologic markers to cognitive trajectories. RESULTS Controlling for pathology, decline in perceptual speed was evident about 15 years before death; modest decline in semantic and working memory occurred later; and there was little change in episodic memory. Each neurodegenerative marker was associated with lower episodic memory function beginning about 10 to 16 years before death. As time before death decreased, Alzheimer disease pathology, Lewy bodies, and hippocampal sclerosis were associated with impairment in other cognitive domains but the association of TDP-43 pathology with cognition continued to be mainly confined to episodic memory. CONCLUSIONS The results suggest that episodic memory impairment is an early sign of multiple neurodegenerative conditions, which primarily differ in their associations with other cognitive systems.
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Affiliation(s)
- Robert S Wilson
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL.
| | - Jingyun Yang
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
| | - Lei Yu
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
| | - Sue E Leurgans
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
| | - Ana W Capuano
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
| | - Julie A Schneider
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
| | - David A Bennett
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
| | - Patricia A Boyle
- From the Departments of Neurological Sciences (R.S.W., J.Y., L.Y., S.E.L., A.W.C., J.A.S., D.A.B.), Behavioral Sciences (R.S.W., P.A.B.), and Pathology (J.A.S.), Rush University Medical Center, Rush Alzheimer's Disease Center, Chicago, IL
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Hunter S, Smailagic N, Brayne C. Dementia Research: Populations, Progress, Problems, and Predictions. J Alzheimers Dis 2018; 64:S119-S143. [DOI: 10.3233/jad-179927] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Sally Hunter
- Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Nadja Smailagic
- Institute of Public Health, University of Cambridge, Cambridge, UK
| | - Carol Brayne
- Institute of Public Health, University of Cambridge, Cambridge, UK
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Winblad B, Amouyel P, Andrieu S, Ballard C, Brayne C, Brodaty H, Cedazo-Minguez A, Dubois B, Edvardsson D, Feldman H, Fratiglioni L, Frisoni GB, Gauthier S, Georges J, Graff C, Iqbal K, Jessen F, Johansson G, Jönsson L, Kivipelto M, Knapp M, Mangialasche F, Melis R, Nordberg A, Rikkert MO, Qiu C, Sakmar TP, Scheltens P, Schneider LS, Sperling R, Tjernberg LO, Waldemar G, Wimo A, Zetterberg H. Defeating Alzheimer's disease and other dementias: a priority for European science and society. Lancet Neurol 2016; 15:455-532. [DOI: 10.1016/s1474-4422(16)00062-4] [Citation(s) in RCA: 1001] [Impact Index Per Article: 125.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/06/2015] [Accepted: 02/09/2016] [Indexed: 12/15/2022]
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Goldman JG, Williams-Gray C, Barker RA, Duda JE, Galvin JE. The spectrum of cognitive impairment in Lewy body diseases. Mov Disord 2014; 29:608-21. [PMID: 24757110 PMCID: PMC4126402 DOI: 10.1002/mds.25866] [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: 12/20/2013] [Revised: 02/15/2014] [Accepted: 02/20/2014] [Indexed: 12/17/2022] Open
Abstract
Cognitive impairment represents an important and often defining component of the clinical syndromes of Lewy body disorders: Parkinson's disease and dementia with Lewy bodies. The spectrum of cognitive deficits in these Lewy body diseases encompasses a broad range of clinical features, severity of impairment, and timing of presentation. It is now recognized that cognitive dysfunction occurs not only in more advanced Parkinson's disease but also in early, untreated patients and even in those patients with pre-motor syndromes, such as rapid eye movement behavior disorder and hyposmia. In recent years, the concept of mild cognitive impairment as a transitional or pre-dementia state in Parkinson's disease has emerged. This has led to much research regarding the diagnosis, prognosis, and underlying neurobiology of mild cognitive impairment in Parkinson's disease, but has also raised questions regarding the usefulness of this concept and its application in clinical and research settings. In addition, the conundrum of whether Parkinson's disease dementia and dementia with Lewy bodies represent the same or different entities remains unresolved. Although these disorders overlap in many aspects of their presentations and pathophysiology, they differ in other elements, such as timing of cognitive, behavioral, and motor symptoms; medication responses; and neuropathological contributions. This article examines the spectrum and evolution of cognitive impairment in Lewy body disorders and debates these controversial issues in the field using point-counterpoint approaches.
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Affiliation(s)
| | - Caroline Williams-Gray
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Roger A. Barker
- John Van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - John E. Duda
- Department of Neurology, University of Pennsylvania Perelman School of Medicine and the Parkinson’s Disease Research, Education and Clinical Center, Philadelphia Veterans Affairs Medical Center, Philadelphia, PA
| | - James E. Galvin
- Departments of Neurology, Psychiatry and Population Health, New York University School of Medicine, New York, NY
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Abstract
SummaryThis systematic review, with meta-analyses conducted where data were available, aimed to investigate the prevalence of symptoms of depression and anxiety in mild cognitive impairment (MCI), and to establish how symptoms of depression and anxiety relate to the progression from no cognitive impairment to MCI, and from MCI to dementia. Sixty studies were included in the review. Meta-analyses indicated that symptoms of depression and anxiety were more prevalent in people with MCI than in people with normal cognitive function, and increased the risk of progression from no cognitive impairment to MCI. There were mixed results regarding the effect of such symptoms on progression from MCI to dementia. The findings highlight the need for more research in this area, which can inform attempts to slow or halt the progression of cognitive impairment in later life, with resulting benefits for quality of life.
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10
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Abstract
Education, occupation, premorbid intelligence, and brain size are surrogate markers for cognitive reserve. Whether these markers have biological influence on Alzheimer disease (AD) pathology is not known. We thus aimed to investigate the effect of cognitive reserve proxies on longitudinal change of AD biomarkers. A total of 819 participants with normal cognition, mild cognitive impairment, and mild AD were enrolled in the Alzheimer's Disease Neuroimaging Initiative and followed up with repeated measures of cerebrospinal fluid, positron emission tomography, and magnetic resonance imaging biomarkers. Generalized estimating equations were used to assess whether biomarker rates of change were modified by reserve proxies. Cerebrospinal fluid Aβ42 decline was slower in normal cognition participants with higher cognitive reserve indexed by education, occupation, and American National Adult Reading Test (ANART). The decline of [F] fluorodeoxyglucose positron emission tomography uptake was slower in AD participants with better performance on the ANART. Education, occupation, and ANART did not modify the rates of magnetic resonance imaging hippocampal atrophy in any group. These findings remained unchanged after accounting for APOE 4, longitudinal missing data, and baseline cognitive performance. Higher levels of reserve markers may slow the rate of amyloid deposition before cognitive impairment and preserve glucose metabolism at the dementia stage over the course of AD pathologic progression.
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Affiliation(s)
- Raymond Y. Lo
- Department of Neurology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
- College of Medicine, Tzu Chi University, Hualien, Taiwan
- Division of Epidemiology, School of Public Health, University of California, Berkeley, CA, USA
| | - William J. Jagust
- Division of Epidemiology, School of Public Health, University of California, Berkeley, CA, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Alichniewicz KK, Brunner F, Klünemann HH, Greenlee MW. Neural correlates of saccadic inhibition in healthy elderly and patients with amnestic mild cognitive impairment. Front Psychol 2013; 4:467. [PMID: 23898312 PMCID: PMC3721022 DOI: 10.3389/fpsyg.2013.00467] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 07/04/2013] [Indexed: 11/25/2022] Open
Abstract
Performance on tasks that require saccadic inhibition declines with age and altered inhibitory functioning has also been reported in patients with Alzheimer's disease. Although mild cognitive impairment (MCI) is assumed to be a high-risk factor for conversion to AD, little is known about changes in saccadic inhibition and its neural correlates in this condition. Our study determined whether the neural activation associated with saccadic inhibition is altered in persons with amnestic mild cognitive impairment (aMCI). Functional magnetic resonance imaging (fMRI) revealed decreased activation in parietal lobe in healthy elderly persons compared to young persons and decreased activation in frontal eye fields in aMCI patients compared to healthy elderly persons during the execution of anti-saccades. These results illustrate that the decline in inhibitory functions is associated with impaired frontal activation in aMCI. This alteration in function might reflect early manifestations of AD and provide new insights in the neural activation changes that occur in pathological ageing.
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Affiliation(s)
- K K Alichniewicz
- Institute of Experimental Psychology, University of Regensburg Regensburg, Germany
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12
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Wang PN, Chou KH, Chang NJ, Lin KN, Chen WT, Lan GY, Lin CP, Lirng JF. Callosal degeneration topographically correlated with cognitive function in amnestic mild cognitive impairment and Alzheimer's disease dementia. Hum Brain Mapp 2013; 35:1529-43. [PMID: 23670960 DOI: 10.1002/hbm.22271] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 09/30/2012] [Accepted: 01/17/2012] [Indexed: 11/09/2022] Open
Abstract
Degeneration of the corpus callosum (CC) is evident in the pathogenesis of Alzheimer's disease (AD). However, the correlation of microstructural damage in the CC on the cognitive performance of patients with amnestic mild cognitive impairment (aMCI) and AD dementia is undetermined. We enrolled 26 normal controls, 24 patients with AD dementia, and 40 single-domain aMCI patients with at least grade 1 hippocampal atrophy and isolated memory impairment. Diffusion tensor imaging (DTI) with fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (DA), and radial diffusivity (DR) were measured. The entire CC was parcellated based on fiber trajectories to specific cortical Brodmann areas using a probabilistic tractography method. The relationship between the DTI measures in the subregions of the CC and cognitive performance was examined. Although the callosal degeneration in the patients with aMCI was less extended than in the patients with AD dementia, degeneration was already exhibited in several subregions of the CC at the aMCI stage. Scores of various neuropsychological tests were correlated to the severity of microstructural changes in the subregional CC connecting to functionally corresponding cortical regions. Our results confirm that CC degeneration is noticeable as early as the aMCI stage of AD and the disconnection of the CC subregional fibers to the corresponding Brodmann areas has an apparent impact on the related cognitive performance.
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Affiliation(s)
- Pei-Ning Wang
- Department of Neurology, National Yang-Ming University, School of Medicine, Taipei, Taiwan; Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan; Brain Research Center, National Yang-Ming University, Taipei, Taiwan
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Stephan BCM, Wharton SB, Simpson J, Matthews FE, Ince P, Brayne C. The epidemiological neuropathology of dementia and the implications for drug development. Neurodegener Dis Manag 2012. [DOI: 10.2217/nmt.12.51] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SUMMARY Identification of the determinants and risk factors for dementia, in addition to the underlying brain changes associated with disease, is fundamental to the development of dementia therapeutics. The gold standard to achieving this is through population-based (epidemiological) studies of the biology of aging, cognitive decline and dementia. In this paper, the main findings from epidemiological cohorts on dementia pathology are compared to case–control and convenience samples, and findings on the different neuropathological features of dementia, its risk factors and clinical course are summarized. The strengths and weakness of different research designs, the keys aspects of disease these have identified and the targets that have been subsequently developed will be discussed. It is highlighted that dementia within epidemiological frameworks is found to be a heterogeneous disease. For treatment to be effective it will therefore need to reflect not only population variation in patterns of pathology, but also intra-individual reactions to these treatments.
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Affiliation(s)
| | - Stephen B Wharton
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Julie Simpson
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | | | - Paul Ince
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Carol Brayne
- Department of Public Health & Primary Care, Forvie Site, Robinson Way, University of Cambridge, CB2 0SR, UK
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Haller S, Missonnier P, Herrmann FR, Rodriguez C, Deiber MP, Nguyen D, Gold G, Lovblad KO, Giannakopoulos P. Individual classification of mild cognitive impairment subtypes by support vector machine analysis of white matter DTI. AJNR Am J Neuroradiol 2012; 34:283-91. [PMID: 22976235 DOI: 10.3174/ajnr.a3223] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND AND PURPOSE MCI was recently subdivided into sd-aMCI, sd-fMCI, and md-aMCI. The current investigation aimed to discriminate between MCI subtypes by using DTI. MATERIALS AND METHODS Sixty-six prospective participants were included: 18 with sd-aMCI, 13 with sd-fMCI, and 35 with md-aMCI. Statistics included group comparisons using TBSS and individual classification using SVMs. RESULTS The group-level analysis revealed a decrease in FA in md-aMCI versus sd-aMCI in an extensive bilateral, right-dominant network, and a more pronounced reduction of FA in md-aMCI compared with sd-fMCI in right inferior fronto-occipital fasciculus and inferior longitudinal fasciculus. The comparison between sd-fMCI and sd-aMCI, as well as the analysis of the other diffusion parameters, yielded no significant group differences. The individual-level SVM analysis provided discrimination between the MCI subtypes with accuracies around 97%. The major limitation is the relatively small number of cases of MCI. CONCLUSIONS Our data show that, at the group level, the md-aMCI subgroup has the most pronounced damage in white matter integrity. Individually, SVM analysis of white matter FA provided highly accurate classification of MCI subtypes.
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Affiliation(s)
- S Haller
- Service neuro-diagnostique et neuro-interventionnel DISIM, Hôpitaux Universitaires de Genève, Rue GabriellePerret-Gentil 4, 1211 Genève 14, Switzerland.
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