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Zhao A, Fang F, Li B, Chen Y, Qiu Y, Wu Y, Xu W, Deng Y. Visual Abnormalities Associate With Hippocampus in Mild Cognitive Impairment and Early Alzheimer's Disease. Front Aging Neurosci 2021; 12:597491. [PMID: 33551787 PMCID: PMC7862343 DOI: 10.3389/fnagi.2020.597491] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 12/28/2020] [Indexed: 01/29/2023] Open
Abstract
Background and Objective: Alzheimer's disease (AD) has been shown to affect vision in human patients and animal models. This study was conducted to explore ocular abnormalities in the primary visual pathway and their relationship with hippocampal atrophy in patients with AD and mild cognitive impairment (MCI). The aim of this study was to investigate the potential value of ocular examinations as a biomarker during the AD progression. Methods: Patients with MCI (n = 23) or AD (n = 17) and age-matched cognitively normal controls (NC; n = 19) were enrolled. Pattern visual-evoked potentials (PVEP), flash electroretinogram (FERG) recordings and optical coherence tomography (OCT) were performed for all participants. Hippocampal volumes were measured by 3T magnetic resonance imaging. Cognitive function was assessed by Mini Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA) and Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog). Pearson correlation was employed to analyze the potential associations between ocular abnormalities and hippocampal volumes. Hierarchical regression models were conducted to determine associations between cognitive performances and ocular abnormalities as well as hippocampal volumes after adjusting for confounding factors including age, sex, cognitive reserve, and APOE4 status. Results: PVEP amplitude of P100 waveform was significantly decreased in AD patients compared to MCI and normal individuals. In FERG test, delayed latencies of rod response, rod cone response and 3.0 flicker time were found in cognitively impaired groups, indicating dysfunctions of both the rod and cone systems in the disease progression. OCT test revealed reduced macular retinal nerve fiber layer (m-RNFL) thickness in MCI and AD patients, which significantly correlated with brain structure of hippocampus particularly vulnerable during the progression of AD. Interestingly, P100 amplitude showed a significant association with hippocampal volumes even after adjusting confounding factors including age, sex, and cognitive reserve. Hierarchical regression analysis further demonstrated that m-RNFL thickness, as well as hippocampal volumes, significantly associated with ADAS-cog scores. Conclusion: P100 amplitude and m-RNFL thickness showed significant correlations with brain structure involved in AD-related neurodegeneration, and therefore proved to be potential indicators of brain imaging pathologies.
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Affiliation(s)
- Aonan Zhao
- Department of Neurology, Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fang Fang
- Department of Geriatrics, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Binyin Li
- Department of Neurology, Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Chen
- Department of Ophthalmology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yinghui Qiu
- Department of Neurology, Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yanli Wu
- Department of Ophthalmology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei Xu
- Department of Neurology, Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yulei Deng
- Department of Neurology, Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Neurology, Ruijin Hospital, Luwan Branch, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Lombardi G, Crescioli G, Cavedo E, Lucenteforte E, Casazza G, Bellatorre A, Lista C, Costantino G, Frisoni G, Virgili G, Filippini G. Structural magnetic resonance imaging for the early diagnosis of dementia due to Alzheimer's disease in people with mild cognitive impairment. Cochrane Database Syst Rev 2020; 3:CD009628. [PMID: 32119112 PMCID: PMC7059964 DOI: 10.1002/14651858.cd009628.pub2] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Mild cognitive impairment (MCI) due to Alzheimer's disease is the symptomatic predementia phase of Alzheimer's disease dementia, characterised by cognitive and functional impairment not severe enough to fulfil the criteria for dementia. In clinical samples, people with amnestic MCI are at high risk of developing Alzheimer's disease dementia, with annual rates of progression from MCI to Alzheimer's disease estimated at approximately 10% to 15% compared with the base incidence rates of Alzheimer's disease dementia of 1% to 2% per year. OBJECTIVES To assess the diagnostic accuracy of structural magnetic resonance imaging (MRI) for the early diagnosis of dementia due to Alzheimer's disease in people with MCI versus the clinical follow-up diagnosis of Alzheimer's disease dementia as a reference standard (delayed verification). To investigate sources of heterogeneity in accuracy, such as the use of qualitative visual assessment or quantitative volumetric measurements, including manual or automatic (MRI) techniques, or the length of follow-up, and age of participants. MRI was evaluated as an add-on test in addition to clinical diagnosis of MCI to improve early diagnosis of dementia due to Alzheimer's disease in people with MCI. SEARCH METHODS On 29 January 2019 we searched Cochrane Dementia and Cognitive Improvement's Specialised Register and the databases, MEDLINE, Embase, BIOSIS Previews, Science Citation Index, PsycINFO, and LILACS. We also searched the reference lists of all eligible studies identified by the electronic searches. SELECTION CRITERIA We considered cohort studies of any size that included prospectively recruited people of any age with a diagnosis of MCI. We included studies that compared the diagnostic test accuracy of baseline structural MRI versus the clinical follow-up diagnosis of Alzheimer's disease dementia (delayed verification). We did not exclude studies on the basis of length of follow-up. We included studies that used either qualitative visual assessment or quantitative volumetric measurements of MRI to detect atrophy in the whole brain or in specific brain regions, such as the hippocampus, medial temporal lobe, lateral ventricles, entorhinal cortex, medial temporal gyrus, lateral temporal lobe, amygdala, and cortical grey matter. DATA COLLECTION AND ANALYSIS Four teams of two review authors each independently reviewed titles and abstracts of articles identified by the search strategy. Two teams of two review authors each independently assessed the selected full-text articles for eligibility, extracted data and solved disagreements by consensus. Two review authors independently assessed the quality of studies using the QUADAS-2 tool. We used the hierarchical summary receiver operating characteristic (HSROC) model to fit summary ROC curves and to obtain overall measures of relative accuracy in subgroup analyses. We also used these models to obtain pooled estimates of sensitivity and specificity when sufficient data sets were available. MAIN RESULTS We included 33 studies, published from 1999 to 2019, with 3935 participants of whom 1341 (34%) progressed to Alzheimer's disease dementia and 2594 (66%) did not. Of the participants who did not progress to Alzheimer's disease dementia, 2561 (99%) remained stable MCI and 33 (1%) progressed to other types of dementia. The median proportion of women was 53% and the mean age of participants ranged from 63 to 87 years (median 73 years). The mean length of clinical follow-up ranged from 1 to 7.6 years (median 2 years). Most studies were of poor methodological quality due to risk of bias for participant selection or the index test, or both. Most of the included studies reported data on the volume of the total hippocampus (pooled mean sensitivity 0.73 (95% confidence interval (CI) 0.64 to 0.80); pooled mean specificity 0.71 (95% CI 0.65 to 0.77); 22 studies, 2209 participants). This evidence was of low certainty due to risk of bias and inconsistency. Seven studies reported data on the atrophy of the medial temporal lobe (mean sensitivity 0.64 (95% CI 0.53 to 0.73); mean specificity 0.65 (95% CI 0.51 to 0.76); 1077 participants) and five studies on the volume of the lateral ventricles (mean sensitivity 0.57 (95% CI 0.49 to 0.65); mean specificity 0.64 (95% CI 0.59 to 0.70); 1077 participants). This evidence was of moderate certainty due to risk of bias. Four studies with 529 participants analysed the volume of the total entorhinal cortex and four studies with 424 participants analysed the volume of the whole brain. We did not estimate pooled sensitivity and specificity for the volume of these two regions because available data were sparse and heterogeneous. We could not statistically evaluate the volumes of the lateral temporal lobe, amygdala, medial temporal gyrus, or cortical grey matter assessed in small individual studies. We found no evidence of a difference between studies in the accuracy of the total hippocampal volume with regards to duration of follow-up or age of participants, but the manual MRI technique was superior to automatic techniques in mixed (mostly indirect) comparisons. We did not assess the relative accuracy of the volumes of different brain regions measured by MRI because only indirect comparisons were available, studies were heterogeneous, and the overall accuracy of all regions was moderate. AUTHORS' CONCLUSIONS The volume of hippocampus or medial temporal lobe, the most studied brain regions, showed low sensitivity and specificity and did not qualify structural MRI as a stand-alone add-on test for an early diagnosis of dementia due to Alzheimer's disease in people with MCI. This is consistent with international guidelines, which recommend imaging to exclude non-degenerative or surgical causes of cognitive impairment and not to diagnose dementia due to Alzheimer's disease. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Future research should not focus on a single biomarker, but rather on combinations of biomarkers to improve an early diagnosis of Alzheimer's disease dementia.
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Affiliation(s)
- Gemma Lombardi
- University of FlorenceDepartment of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA)Largo Brambilla, 3FlorenceItaly50134
| | - Giada Crescioli
- University of FlorenceDepartment of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA)Largo Brambilla, 3FlorenceItaly50134
| | - Enrica Cavedo
- Pitie‐Salpetriere Hospital, Sorbonne UniversityAlzheimer Precision Medicine (APM), AP‐HP47 boulevard de l'HopitalParisFrance75013
| | - Ersilia Lucenteforte
- University of PisaDepartment of Clinical and Experimental MedicineVia Savi 10PisaItaly56126
| | - Giovanni Casazza
- Università degli Studi di MilanoDipartimento di Scienze Biomediche e Cliniche "L. Sacco"via GB Grassi 74MilanItaly20157
| | | | - Chiara Lista
- Fondazione I.R.C.C.S. Istituto Neurologico Carlo BestaNeuroepidemiology UnitVia Celoria, 11MilanoItaly20133
| | - Giorgio Costantino
- Ospedale Maggiore Policlinico, Università degli Studi di MilanoUOC Pronto Soccorso e Medicina D'Urgenza, Fondazione IRCCS Ca' GrandaMilanItaly
| | | | - Gianni Virgili
- University of FlorenceDepartment of Neurosciences, Psychology, Drug Research and Child Health (NEUROFARBA)Largo Brambilla, 3FlorenceItaly50134
| | - Graziella Filippini
- Carlo Besta Foundation and Neurological InstituteScientific Director’s Officevia Celoria, 11MilanItaly20133
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Tao R, Lu Z, Ding D, Fu S, Hong Z, Liang X, Zheng L, Xiao Y, Zhao Q. Perifovea retinal thickness as an ophthalmic biomarker for mild cognitive impairment and early Alzheimer's disease. ALZHEIMER'S & DEMENTIA: DIAGNOSIS, ASSESSMENT & DISEASE MONITORING 2019; 11:405-414. [PMID: 31206006 PMCID: PMC6558027 DOI: 10.1016/j.dadm.2019.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Introduction The aim of this study was to investigate retinal thickness as a biomarker for identifying patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Methods The retinal thickness, utilizing the spectral domain optical coherence tomography, was compared among 73 patients with AD, 51 patients with MCI, 67 cognitive normal control (NC) subjects. Results The retinal thickness of ganglion cell complex and peripapillary retinal nerve fiber layer decreased in both AD and MCI patients, in comparison with NC subjects (AD vs. NC, P < .01; MCI vs. NC, P < .01). The inner retinal layers in macular area in MCI exhibited significant thinning compared with NC (P < .001). Remarkable association was found between the retinal thickness and brain volume (P < .05). Better correlation was seen between the inner perifovea retinal thickness and the hippocampal and entorhinal cortex volume (r: 0.427–0.644, P < .01). Discussion The retinal thickness, especially the inner retinal layer thickness, is a potentially early AD marker indicating neurodegeneration.
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Affiliation(s)
- Rui Tao
- Department of Ophthalmology, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhaozeng Lu
- Department of Ophthalmology, Huashan Hospital, Fudan University, Shanghai, China
| | - Ding Ding
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Shuhao Fu
- Department of Ophthalmology, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhen Hong
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaoniu Liang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Li Zheng
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yiqin Xiao
- Department of Ophthalmology, Huashan Hospital, Fudan University, Shanghai, China
| | - Qianhua Zhao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
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Teipel SJ, Cavedo E, Hampel H, Grothe MJ. Basal Forebrain Volume, but Not Hippocampal Volume, Is a Predictor of Global Cognitive Decline in Patients With Alzheimer's Disease Treated With Cholinesterase Inhibitors. Front Neurol 2018; 9:642. [PMID: 30158893 PMCID: PMC6104491 DOI: 10.3389/fneur.2018.00642] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Background: Predicting the progression of cognitive decline in Alzheimer's disease (AD) is important for treatment selection and patient counseling. Structural MRI markers such as hippocampus or basal forebrain volumes might represent useful instruments for the prediction of cognitive decline. The primary objective was to determine the predictive value of hippocampus and basal forebrain volumes for global and domain specific cognitive decline in AD dementia during cholinergic treatment. Methods: We used MRI and cognitive data from 124 patients with the clinical diagnosis of AD dementia, derived from the ADNI-1 cohort, who were on standard of care cholinesterase inhibitor treatment during a follow-up period between 0.4 and 3.1 years. We used linear mixed effects models with cognitive function as outcome to assess the main effects as well as two-way interactions between baseline volumes and time controlling for age, sex, and total intracranial volume. This model accounts for individual variation in follow-up times. Results: Basal forebrain volume, but not hippocampus volume, was a significant predictor of rates of global cognitive decline. Larger volumes were associated with smaller rates of cognitive decline. Left hippocampus volume had a modest association with rates of episodic memory decline. Baseline performance in global cognition and memory was significantly associated with hippocampus and basal forebrain volumes; in addition, basal forebrain volume was associated with baseline performance in executive function. Conclusions: Our findings indicate that in AD dementia patients, basal forebrain volume may be a useful marker to predict subsequent cognitive decline during cholinergic treatment.
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Affiliation(s)
- Stefan J Teipel
- German Center for Neurodegenerative Diseases-Rostock/Greifswald, Rostock, Germany.,Department of Psychosomatic Medicine, University of Rostock, Rostock, Germany
| | - Enrica Cavedo
- AXA Research Fund and Sorbonne University Chair, Paris, France.,Sorbonne University, GRC n° 21, Alzheimer Precision Medicine, AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'Hôpital, Paris, France.,Brain and Spine Institute (ICM), INSERM U 1127, CNRS UMR 7225, Boulevard de l'Hôpital, Paris, France.,Department of Neurology, Institute of Memory and Alzheimer's Disease (IM2A), Pitié-Salpêtrière Hospital, AP-HP, Boulevard de l'Hôpital, Paris, France.,IRCCS Istituto Centro San Giovanni di Dio-Fatebenefratelli, Brescia, Italy
| | - Harald Hampel
- AXA Research Fund and Sorbonne University Chair, Paris, France.,Sorbonne University, GRC n° 21, Alzheimer Precision Medicine, AP-HP, Pitié-Salpêtrière Hospital, Boulevard de l'Hôpital, Paris, France.,Brain and Spine Institute (ICM), INSERM U 1127, CNRS UMR 7225, Boulevard de l'Hôpital, Paris, France.,Department of Neurology, Institute of Memory and Alzheimer's Disease (IM2A), Pitié-Salpêtrière Hospital, AP-HP, Boulevard de l'Hôpital, Paris, France
| | - Michel J Grothe
- German Center for Neurodegenerative Diseases-Rostock/Greifswald, Rostock, Germany
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Abstract
OBJECTIVES Mild cognitive impairments (MCI) is a transitional state in aging associated with increased risk of incident dementia. The current study investigated whether MCI status moderated the effect of time on word generation during verbal fluency tasks. Specifically, the objective was to determine whether MCI status had differential effects on initial automatic or latter more effortful retrieval processes of fluency tasks. METHODS Participants were community residing older adults enrolled in a longitudinal cohort study. Of the 408 participants, 353 were normal (age=76.06±6.61; %female=57.8) and 55 were diagnosed with MCI (age=78.62±7.00; %female=52.7). Phonemic and category fluency were each administered for 60 s, but performance was recorded at three consecutive 20-s intervals (0-20 s [T1], 21-40 s [T2], 41-60 s [T3]. Separate linear mixed effects models for each fluency task were used to determine the effects of group, time, and their interaction on word generation. RESULTS In both fluency tasks, word generation declined as a function of time. Individuals with MCI generated fewer words compared to controls during the first 20 s of phonemic (beta=-1.56; p<.001; d=0.28) and category fluency (beta=-1.85; p<.001; d=0.37). Group by time interactions revealed that individuals with MCI demonstrated attenuated declines in word generation from the first to the second and third time intervals of both phonemic ([T1 vs. T2] beta=2.17, p=.001; d=0.41; [T1 vs. T3]beta=2.28, p=.001; d=0.45) and category ([T1 vs. T2] beta= 2.22, p=.002; d=0.50; [T1 vs. T3]beta=3.16, p<.001; d=0.71) fluency. CONCLUSIONS Early automatic retrieval processes in verbal fluency tasks are compromised in MCI. (JINS, 2017, 23, 44-55).
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Affiliation(s)
- Eleni Demetriou
- 1Ferkauf Graduate School of Psychology,Yeshiva University,New York,New York
| | - Roee Holtzer
- 1Ferkauf Graduate School of Psychology,Yeshiva University,New York,New York
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Fayed N, Modrego PJ, García-Martí G, Sanz-Requena R, Marti-Bonmatí L. Magnetic resonance spectroscopy and brain volumetry in mild cognitive impairment. A prospective study. Magn Reson Imaging 2016; 38:27-32. [PMID: 27964994 DOI: 10.1016/j.mri.2016.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 12/08/2016] [Accepted: 12/08/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE To assess the accuracy of magnetic resonance spectroscopy (1H-MRS) and brain volumetry in mild cognitive impairment (MCI) to predict conversion to probable Alzheimer's disease (AD). METHODS Forty-eight patients fulfilling the criteria of amnestic MCI who underwent a conventional magnetic resonance imaging (MRI) followed by MRS, and T1-3D on 1.5 Tesla MR unit. At baseline the patients underwent neuropsychological examination. 1H-MRS of the brain was carried out by exploring the left medial occipital lobe and ventral posterior cingulated cortex (vPCC) using the LCModel software. A high resolution T1-3D sequence was acquired to carry out the volumetric measurement. A cortical and subcortical parcellation strategy was used to obtain the volumes of each area within the brain. The patients were followed up to detect conversion to probable AD. RESULTS After a 3-year follow-up, 15 (31.2%) patients converted to AD. The myo-inositol in the occipital cortex and glutamate+glutamine (Glx) in the posterior cingulate cortex predicted conversion to probable AD at 46.1% sensitivity and 90.6% specificity. The positive predictive value was 66.7%, and the negative predictive value was 80.6%, with an overall cross-validated classification accuracy of 77.8%. The volume of the third ventricle, the total white matter and entorhinal cortex predict conversion to probable AD at 46.7% sensitivity and 90.9% specificity. The positive predictive value was 70%, and the negative predictive value was 78.9%, with an overall cross-validated classification accuracy of 77.1%. Combining volumetric measures in addition to the MRS measures the prediction to probable AD has a 38.5% sensitivity and 87.5% specificity, with a positive predictive value of 55.6%, a negative predictive value of 77.8% and an overall accuracy of 73.3%. CONCLUSION Either MRS or brain volumetric measures are markers separately of cognitive decline and may serve as a noninvasive tool to monitor cognitive changes and progression to dementia in patients with amnestic MCI, but the results do not support the routine use in the clinical settings.
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Affiliation(s)
- Nicolás Fayed
- Radiology Department, Quirón Hospital, Zaragoza 50009, Spain
| | - Pedro J Modrego
- Department of Neurology, Miguel Servet Hospital, Zaragoza 50009, Spain.
| | - Gracián García-Martí
- Biomedical Engineering, Quirón Hospital, Valencia, Spain; CIBERSAM, Mental Research Network, Valencia, Spain
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Teipel SJ, Cavedo E, Grothe MJ, Lista S, Galluzzi S, Colliot O, Chupin M, Bakardjian H, Dormont D, Dubois B, Hampel H. Predictors of cognitive decline and treatment response in a clinical trial on suspected prodromal Alzheimer's disease. Neuropharmacology 2016; 108:128-35. [PMID: 26876309 DOI: 10.1016/j.neuropharm.2016.02.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 02/01/2016] [Accepted: 02/05/2016] [Indexed: 11/28/2022]
Abstract
UNLABELLED We determined the value of hippocampus (Hp) and basal forebrain (BF) volumes for predicting cognitive decline and treatment response in a double-blind, randomized, placebo-controlled phase 4 trial at 28 academic centers (France) in patients with amnestic mild cognitive impairment (MCI) receiving Donepezil 10 mg daily or placebo over 12 months, and 6 months open label follow-up. Outcome measures were the rates of global and domain specific cognitive decline as non-primary efficacy endpoint. The intention-to-treat (ITT) sample analyzed comprised 215 cases. Baseline Hp volume was a significant predictor of rates of change in global cognitive function in linear mixed effects models. This effect was independent of treatment. BF volume was not associated with rates of global or domain specific cognitive decline. Rates of delayed free recall decline were higher in MCI cases treated with donepezil compared to placebo. Only Hp, but not BF volume was a useful predictor of cognitive decline in suspected prodromal AD patients. Both Hp and BF volumes were poor predictors of treatment response, questioning previous approaches on predicting treatment response without placebo control. TRIAL REGISTRATION clinicalTrials.gov Identifier NCT00403520.
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Affiliation(s)
- Stefan J Teipel
- German Center for Neurodegenerative Diseases (DZNE) - Rostock/Greifswald, Rostock, Germany; Department of Psychosomatic Medicine, University of Rostock, Rostock, Germany.
| | - Enrica Cavedo
- Institut de la Memoire et de la Maladie d'Alzheimer (IM2A), Departement de Neurologie, Hôpital de la Pitie-Salpêtriere, AP-HP, Paris, France; INSERM U1127, Institut du Cerveau et de la Moelle Epiniere (ICM), Paris, France; Sorbonne Universites, Universite Pierre et Marie Curie-Paris 6, Paris, France; CATI Multicenter Neuroimaging Platform, France; IRCCS Istituto Centro San Giovanni di Dio-Fatebenefratelli, Italy
| | - Michel J Grothe
- German Center for Neurodegenerative Diseases (DZNE) - Rostock/Greifswald, Rostock, Germany; Department of Psychosomatic Medicine, University of Rostock, Rostock, Germany
| | - Simone Lista
- Institut de la Memoire et de la Maladie d'Alzheimer (IM2A), Departement de Neurologie, Hôpital de la Pitie-Salpêtriere, AP-HP, Paris, France; INSERM U1127, Institut du Cerveau et de la Moelle Epiniere (ICM), Paris, France; Sorbonne Universites, Universite Pierre et Marie Curie-Paris 6, Paris, France; AXA Research Fund & UPMC Chair, Paris, France
| | | | - Olivier Colliot
- Inserm, U1127, F-75013, Paris, France; CNRS, UMR 7225 ICM, 75013, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013, Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France; Inria, Aramis Project-team, Centre de Recherche Paris-Rocquencourt, France
| | - Marie Chupin
- Inserm, U1127, F-75013, Paris, France; CNRS, UMR 7225 ICM, 75013, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013, Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France; Inria, Aramis Project-team, Centre de Recherche Paris-Rocquencourt, France
| | - Hovagim Bakardjian
- Institut de la Memoire et de la Maladie d'Alzheimer (IM2A), Departement de Neurologie, Hôpital de la Pitie-Salpêtriere, AP-HP, Paris, France; IHU-A-ICM - Paris Institute of Translational Neurosciences, Paris, France
| | - Didier Dormont
- Inserm, U1127, F-75013, Paris, France; CNRS, UMR 7225 ICM, 75013, Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR S 1127, F-75013, Paris, France; Institut du Cerveau et de la Moelle épinière, ICM, F-75013, Paris, France; Neuroradiology Department, Hôpital de la Salpêtriere, Paris, France
| | - Bruno Dubois
- Institut de la Memoire et de la Maladie d'Alzheimer (IM2A), Departement de Neurologie, Hôpital de la Pitie-Salpêtriere, AP-HP, Paris, France; INSERM U1127, Institut du Cerveau et de la Moelle Epiniere (ICM), Paris, France; Sorbonne Universites, Universite Pierre et Marie Curie-Paris 6, Paris, France
| | - Harald Hampel
- Institut de la Memoire et de la Maladie d'Alzheimer (IM2A), Departement de Neurologie, Hôpital de la Pitie-Salpêtriere, AP-HP, Paris, France; INSERM U1127, Institut du Cerveau et de la Moelle Epiniere (ICM), Paris, France; Sorbonne Universites, Universite Pierre et Marie Curie-Paris 6, Paris, France; AXA Research Fund & UPMC Chair, Paris, France
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Xiang J, Guo H, Cao R, Liang H, Chen J. An abnormal resting-state functional brain network indicates progression towards Alzheimer's disease. Neural Regen Res 2014; 8:2789-99. [PMID: 25206600 PMCID: PMC4146017 DOI: 10.3969/j.issn.1673-5374.2013.30.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 08/28/2013] [Indexed: 11/18/2022] Open
Abstract
Brain structure and cognitive function change in the temporal lobe, hippocampus, and prefrontal cortex of patients with mild cognitive impairment and Alzheimer's disease, and brain network-connection strength, network efficiency, and nodal attributes are abnormal. However, existing research has only analyzed the differences between these patients and normal controls. In this study, we constructed brain networks using resting-state functional MRI data that was extracted from four populations (normal controls, patients with early mild cognitive impairment, patients with late mild cognitive impairment, and patients with Alzheimer's disease) using the Alzheimer's Disease Neuroimaging Initiative data set. The aim was to analyze the characteristics of resting-state functional neural networks, and to observe mild cognitive impairment at different stages before the transformation to Alzheimer's disease. Results showed that as cognitive deficits increased across the four groups, the shortest path in the resting-state functional network gradually increased, while clustering coefficients gradually decreased. This evidence indicates that dementia is associated with a decline of brain network efficiency. In addition, the changes in functional networks revealed the progressive deterioration of network function across brain regions from healthy elderly adults to those with mild cognitive impairment and Alzheimer's disease. The alterations of node attributes in brain regions may reflect the cognitive functions in brain regions, and we speculate that early impairments in memory, hearing, and language function can eventually lead to diffuse brain injury and other cognitive impairments.
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Affiliation(s)
- Jie Xiang
- College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi Province, China ; International WIC Institute, Beijing University of Technology, Beijing 100022, China
| | - Hao Guo
- College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi Province, China
| | - Rui Cao
- College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi Province, China
| | - Hong Liang
- College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi Province, China
| | - Junjie Chen
- College of Computer Science and Technology, Taiyuan University of Technology, Taiyuan 030024, Shanxi Province, China
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9
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The value of hippocampal and temporal horn volumes and rates of change in predicting future conversion to AD. Alzheimer Dis Assoc Disord 2013; 27:168-73. [PMID: 22760170 PMCID: PMC4154837 DOI: 10.1097/wad.0b013e318260a79a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hippocampal pathology occurs early in Alzheimer disease (AD), and atrophy, measured by volumes and volume changes, may predict which subjects will develop AD. Measures of the temporal horn (TH), which is situated adjacent to the hippocampus, may also indicate early changes in AD. Previous studies suggest that these metrics can predict conversion from amnestic mild cognitive impairment (MCI) to AD with conversion and volume change measured concurrently. However, the ability of these metrics to predict future conversion has not been investigated. We compared the abilities of hippocampal, TH, and global measures to predict future conversion from MCI to AD. TH, hippocampi, whole brain, and ventricles were measured using baseline and 12-month scans. Boundary shift integral was used to measure the rate of change. We investigated the prediction of conversion between 12 and 24 months in subjects classified as MCI from baseline to 12 months. All measures were predictive of future conversion. Local and global rates of change were similarly predictive of conversion. There was evidence that the TH expansion rate is more predictive than the hippocampal atrophy rate (P=0.023) and that the TH expansion rate is more predictive than the TH volume (P=0.036). Prodromal atrophy rates may be useful predictors of future conversion to sporadic AD from amnestic MCI.
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10
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James BD, Caffo B, Stewart WF, Yousem D, Davatzikos C, Schwartz BS. Genetic risk factors for longitudinal changes in structural MRI in former organolead workers. J Aging Res 2011; 2011:362189. [PMID: 22028967 PMCID: PMC3199062 DOI: 10.4061/2011/362189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 07/31/2011] [Indexed: 11/20/2022] Open
Abstract
This study examined associations between polymorphisms in three genes, apolipoprotein E (APOE), angiotensin converting enzyme (ACE), and vitamin D receptor (VDR), and longitudinal change in brain volumes and white matter lesions (WML) as well as effect modification by cardiovascular factors and tibia lead concentrations. Two MRIs, an average of 5 years apart, were obtained for 317 former organolead workers and 45 population-based controls. Both regions-of-interest and voxel-wise analyses were conducted. APOE ε3/ε4 and ε4/ε4 genotypes were associated with less decline in white matter volumes. There was some evidence of interaction between genetic polymorphisms and cardiovascular risk factors (ACE and high-density lipoprotein; VDR and diabetes) on brain volume decline. The VDR FokI ff genotype was associated with an increase in WML (no association for APOE or ACE). This study expands our understanding of how genetic precursors of dementia and cardiovascular diseases are related to changes in brain structure.
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Affiliation(s)
- Bryan D. James
- Rush University Alzheimer's Disease Center, Rush University Medical Center, Room 1038, Chicago, IL 60612, USA
- Department of Internal Medicine, Rush University Medical Center, Chicago, IL 60612, USA
| | - Brian Caffo
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Walter F. Stewart
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Center for Health Research and Rural Advocacy, Geisinger Clinic, Danville, PA 17822, USA
| | - David Yousem
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21278, USA
| | - Christos Davatzikos
- Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Brian S. Schwartz
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21278, USA
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11
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Risacher SL, Shen L, West JD, Kim S, McDonald BC, Beckett LA, Harvey DJ, Jack CR, Weiner MW, Saykin AJ. Longitudinal MRI atrophy biomarkers: relationship to conversion in the ADNI cohort. Neurobiol Aging 2011; 31:1401-18. [PMID: 20620664 DOI: 10.1016/j.neurobiolaging.2010.04.029] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 04/25/2010] [Accepted: 04/27/2010] [Indexed: 10/19/2022]
Abstract
Atrophic changes in early Alzheimer's disease (AD) and amnestic mild cognitive impairment (MCI) have been proposed as biomarkers for detection and monitoring. We analyzed magnetic resonance imaging (MRI) atrophy rate from baseline to 1 year in 4 groups of participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI): AD (n = 152), converters from MCI to probable AD (MCI-C, n = 60), stable MCI (MCI-S, n = 261), and healthy controls (HC, n = 200). Scans were analyzed using multiple methods, including voxel-based morphometry (VBM), regions of interest (ROIs), and automated parcellation, permitting comparison of annual percent change (APC) in neurodegeneration markers. Effect sizes and the sample required to detect 25% reduction in atrophy rates were calculated. The influence of APOE genotype on APC was also evaluated. AD patients and converters from MCI to probable AD demonstrated high atrophy APCs across regions compared with minimal change in healthy controls. Stable MCI subjects showed intermediate atrophy rates. APOE genotype was associated with APC in key regions. In sum, APC rates are influenced by APOE genotype, imminent MCI to AD conversion, and AD-related neurodegeneration.
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Affiliation(s)
- Shannon L Risacher
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University, School of Medicine, 950 W Walnut St., Indianapolis, IN 46202, United States
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12
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Clément F, Belleville S, Mellah S. Functional neuroanatomy of the encoding and retrieval processes of verbal episodic memory in MCI. Cortex 2010; 46:1005-15. [DOI: 10.1016/j.cortex.2009.07.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 04/16/2009] [Accepted: 07/06/2009] [Indexed: 11/28/2022]
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He J, Farias S, Martinez O, Reed B, Mungas D, Decarli C. Differences in brain volume, hippocampal volume, cerebrovascular risk factors, and apolipoprotein E4 among mild cognitive impairment subtypes. ACTA ACUST UNITED AC 2009; 66:1393-9. [PMID: 19901172 DOI: 10.1001/archneurol.2009.252] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVES To evaluate demographics, magnetic resonance imaging (MRI) measures, and vascular risk among mild cognitive impairment (MCI) subtypes. DESIGN Cross-sectional study. SETTING Both clinics and the community. PARTICIPANTS A total of 153 subjects with MCI, 218 cognitively normal older individuals (controls), and 68 patients with Alzheimer disease. MAIN OUTCOME MEASURES Classification of subjects with MCI according to current subtype diagnostic convention based on neuropsychological performance, estimates of vascular risk based on medical history, research MRI unless there was a specific contraindication, and apolipoprotein E genotype. RESULTS Of the 153 subjects with MCI, 65 were diagnosed with amnestic single-domain, 46 with amnestic multiple-domain, 27 with nonamnestic single-domain, and 15 with nonamnestic multiple-domain MCI. Analyses of control, MCI, and Alzheimer disease cases revealed significant differences in brain and hippocampal volumes between each group. Post hoc analyses of MRI measures among the MCI subtypes found that patients with amnestic single-domain MCI had significantly less brain atrophy and that hippocampal volume differed significantly from controls for the 2 amnestic forms of MCI. Apolipoprotein E genotype prevalence was significantly greater in the amnestic and nonamnestic subtypes of MCI. Conversely, the nonamnestic subtypes were more likely to have increased vascular risk and to be African American. CONCLUSIONS Amnestic forms of MCI appear to have demographic, genetic, and MRI findings suggestive of Alzheimer disease pathology, whereas the nonamnestic forms of MCI have findings suggestive of vascular disease. Importantly, however, all subjects with MCI showed evidence of brain injury, and the biological differences among subtypes are relatively subtle beyond the memory vs nonmemory groupings.
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Affiliation(s)
- Jing He
- Department of Neurology, and the Imaging of Dementia and Aging Laboratory, Center for Neuroscience Preventive Medicine, University of California at Davis, Sacramento, CA 95817, USA
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14
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Mitchell AJ, Shiri-Feshki M. Rate of progression of mild cognitive impairment to dementia--meta-analysis of 41 robust inception cohort studies. Acta Psychiatr Scand 2009; 119:252-65. [PMID: 19236314 DOI: 10.1111/j.1600-0447.2008.01326.x] [Citation(s) in RCA: 1002] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To quantify the risk of developing dementia in those with mild cognitive impairment (MCI). METHOD Meta-analysis of inception cohort studies. RESULTS Forty-one robust cohort studies were identified. To avoid heterogeneity clinical studies, population studies and clinical trials were analysed separately. Using Mayo defined MCI at baseline and adjusting for sample size, the cumulative proportion who progressed to dementia, to Alzheimer's disease (AD) and to vascular dementia (VaD) was 39.2%, 33.6% and 6.2%, respectively in specialist settings and 21.9%, 28.9% and 5.2%, respectively in population studies. The adjusted annual conversion rate (ACR) from Mayo defined MCI to dementia, AD and VaD was 9.6%, 8.1% and 1.9%, respectively in specialist clinical settings and 4.9%, 6.8% and 1.6% in community studies. Figures from non-Mayo defined MCI and clinical trials are also reported. CONCLUSION The ACR is approximately 5-10% and most people with MCI will not progress to dementia even after 10 years of follow-up.
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Affiliation(s)
- A J Mitchell
- Liaison Psychiatry, Leicester Partnership Trust and University of Leicester, Leicester, UK.
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15
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Sluimer JD, Bouwman FH, Vrenken H, Blankenstein MA, Barkhof F, van der Flier WM, Scheltens P. Whole-brain atrophy rate and CSF biomarker levels in MCI and AD: a longitudinal study. Neurobiol Aging 2008; 31:758-64. [PMID: 18692273 DOI: 10.1016/j.neurobiolaging.2008.06.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2007] [Revised: 06/17/2008] [Accepted: 06/29/2008] [Indexed: 01/08/2023]
Abstract
OBJECTIVES To assess associations between cerebrospinal fluid (CSF) biomarker levels and MRI-based whole-brain atrophy rate in mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS We included 99 patients (47 AD, 29 MCI, 23 controls) who underwent lumbar puncture at baseline and repeat MRI. A subgroup of 48 patients underwent a second lumbar puncture. CSF levels of beta-amyloid(1-42) (A beta(1-42)), tau and tau phosphorylated at threonine-181 (P-tau(181)), and whole-brain atrophy rate were measured. RESULTS Across groups, baseline A beta(1-42) and tau were modestly associated with whole-brain atrophy rate. Adjusted for age, sex and diagnosis, we found no association between A beta(1-42) or tau, and whole-brain atrophy rate. By contrast, high CSF levels of P-tau(181) showed a mild association with a lower whole-brain atrophy rate in AD but not in controls or MCI patients. Finally, whole-brain atrophy rate was associated with change in MMSE, but change in CSF biomarker levels was not. CONCLUSIONS Whole-brain atrophy rate and CSF levels of A beta(1-42,) tau or P-tau(181) provide complementary information in patients with MCI and AD.
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Affiliation(s)
- Jasper D Sluimer
- Alzheimer Centre and Department of Diagnostic Radiology, VU University Medical Center, Amsterdam, The Netherlands.
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16
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Ikram MA, Vrooman HA, Vernooij MW, den Heijer T, Hofman A, Niessen WJ, van der Lugt A, Koudstaal PJ, Breteler MMB. Brain tissue volumes in relation to cognitive function and risk of dementia. Neurobiol Aging 2008; 31:378-86. [PMID: 18501994 DOI: 10.1016/j.neurobiolaging.2008.04.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 03/25/2008] [Accepted: 04/09/2008] [Indexed: 12/14/2022]
Abstract
We investigated in a population-based cohort study the association of global and lobar brain tissue volumes with specific cognitive domains and risk of dementia. Participants (n=490; 60-90 years) were non-demented at baseline (1995-1996). From baseline brain MRI-scans we obtained global and lobar volumes of CSF, GM, normal WM, white matter lesions and hippocampus. We performed neuropsychological testing at baseline to assess information processing speed, executive function, memory function and global cognitive function. Participants were followed for incident dementia until January 1, 2005. Larger volumes of CSF and WML were associated with worse performance on all neuropsychological tests, and an increased risk of dementia. Smaller WM volume was related to poorer information processing speed and executive function. In contrast, smaller GM volume was associated with worse memory function and increased risk of dementia. When investigating lobar GM volumes, we found that hippocampal volume and temporal GM volume were most strongly associated with risk of dementia, even in persons without objective and subjective cognitive deficits at baseline, followed by frontal and parietal GM volumes.
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Affiliation(s)
- M Arfan Ikram
- Department of Epidemiology, Erasmus MC University Medical Center, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands
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Llewellyn DJ, Lang IA, Xie J, Huppert FA, Melzer D, Langa KM. Framingham Stroke Risk Profile and poor cognitive function: a population-based study. BMC Neurol 2008; 8:12. [PMID: 18430227 PMCID: PMC2386808 DOI: 10.1186/1471-2377-8-12] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Accepted: 04/22/2008] [Indexed: 11/10/2022] Open
Abstract
Background The relationship between stroke risk and cognitive function has not previously been examined in a large community living sample other than the Framingham cohort. The objective of this study was to examine the relationship between 10-year risk for incident stroke and cognitive function in a large population-based sample. Methods Participants were 7377 adults aged 50 years and over of the 2002 wave of the English Longitudinal Study of Ageing, a prospective cohort study. A modified version of the Framingham Stroke Risk Profile (incorporating age, sex, systolic blood pressure, antihypertensive medication, diabetes, smoking status, cardiovascular disease, and atrial fibrillation) was used to assess 10-year risk of stroke. Linear regression models were used to determine the cross-sectional relationship of stroke risk to global cognitive function and performance in multiple cognitive domains. Results In unadjusted models 10 percentage point increments of 10-year stroke risk were associated with poor global cognitive function (-0.40 SD units, 95% CI -0.43 – -0.38), and lowered performance in all cognitive domains. After statistical adjustment for age, sex, testing interval and other correlates of cognitive function the association with stroke risk was attenuated though remained significant for global cognitive function (-0.06 SD units, 95% CI -0.09 – -0.03), immediate and delayed verbal memory, semantic verbal fluency and processing speed. Conclusion In individuals free from a history of stroke or dementia, high subclinical cerebrovascular disease burden was associated with worse cognitive function in multiple domains.
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Affiliation(s)
- David J Llewellyn
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
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18
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Ries ML, Carlsson CM, Rowley HA, Sager MA, Gleason CE, Asthana S, Johnson SC. Magnetic resonance imaging characterization of brain structure and function in mild cognitive impairment: a review. J Am Geriatr Soc 2008; 56:920-34. [PMID: 18410325 DOI: 10.1111/j.1532-5415.2008.01684.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Given the predicted increase in prevalence of Alzheimer's disease (AD) in the coming decades, early detection and intervention in persons with the predementia condition known as mild cognitive impairment (MCI) is of paramount importance. Recent years have seen remarkable advances in the application of neuroimaging and other biomarkers to the study of MCI. This article reviews the most recent developments in the use of magnetic resonance imaging (MRI) to characterize brain changes and to prognosticate clinical outcomes of patients with MCI. The review begins with description of methods and findings in structural MRI research, delineating findings regarding both gross atrophy and microstructural brain changes in MCI. Second, we describe the most recent findings regarding brain function in MCI, enumerating findings from functional MRI and brain perfusion studies. Third, we will make recommendations regarding the current clinical use of MRI in identification of MCI. As a conclusion, we will look to the future of neuroimaging as a tool in early AD detection.
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Affiliation(s)
- Michele L Ries
- William S. Middleton Memorial Veterans Hospital Geriatric Research Education and Clinical Center, Madison, Wisconsin 53705, USA.
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19
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Henry-Feugeas MC. Alzheimer’s disease in late-life dementia: A minor toxic consequence of devastating cerebrovascular dysfunction. Med Hypotheses 2008; 70:866-75. [PMID: 17825499 DOI: 10.1016/j.mehy.2007.07.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Accepted: 07/16/2007] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease (AD) is thought to be the most common cause of late-life dementia. But pure AD is infrequent whereas AD pathology is often insufficient to explain dementia in the elderly. Conversely, cerebrovascular disease is omnipresent and the crucial role of microvascular alterations increasingly recognized in late dementia or "Alzheimer syndrome". Pathomechanisms of vascular cognitive impairment are still debated but recent data indicate that the initial concept of chronic low grade cerebral hypoxia should not have been abandoned. Thus, it is proposed that windkessel dysfunction is the missing link between vascular and craniospinal senescence on the one hand, and chronic low grade cerebral hypoxia, "senile brain degeneration" and "Alzheimer syndrome" on the other hand. An age-related decrease in the buffering capacity of both the vessels and the craniospinal cavity favours cerebral hypoxia; due to increased capillary pulsatility with disturbances in capillary exchanges or due to a marked reduction in craniospinal compliance with a mechanical reduction in cerebral arterial inflow. "Invisible" windkessel dysfunction, most often related to "hardening of the arteries" may be the most frequent pathomechanism of late-onset dementia whereas associated mild or moderate AD may be merely a toxic manifestation of a primarily hypoxic disease. Structural patterns of arteriosclerotic dementia fit well with an underlying arterial windkessel dysfunction: with secondary mechanical damage to the cerebral small vessels and the brain and predominantly deep hypoxia. The clinical significance of leukoaraïosis, small foci of necrosis, ventricular dilatation, hippocampal and cortical atrophy is in good agreement with their value as indirect markers of windkessel dysfunction. An age-related "invisible" reduction in craniospinal compliance may also contribute to the associations between heart failure, arterial hypotension and cognitive impairment in the elderly and to the high percentage of dementia of unknown origin in the very old. Both neuropathological and clinical overlap between AD and windkessel dysfunction can explain that cerebrovascular dysfunction remains misdiagnosed for AD in the elderly. Evidence of the key role of cerebrovascular dysfunction should markedly facilitate and widen therapeutic research in late-life dementia. Routine MRI including direct assessment of intracranial dynamics should be increasingly used to define etiological subtypes of the "Alzheimer syndrome" and develop a well-targeted therapeutic strategy.
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Affiliation(s)
- M C Henry-Feugeas
- Department of Radiology, Bichat-Claude Bernard University Hospital, AP-HP, Paris Cedex 18, France.
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Whitwell JL, Przybelski SA, Weigand SD, Knopman DS, Boeve BF, Petersen RC, Jack CR. 3D maps from multiple MRI illustrate changing atrophy patterns as subjects progress from mild cognitive impairment to Alzheimer's disease. Brain 2007; 130:1777-86. [PMID: 17533169 PMCID: PMC2752411 DOI: 10.1093/brain/awm112] [Citation(s) in RCA: 405] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mild cognitive impairment (MCI), particularly the amnestic subtype (aMCI), is considered as a transitional stage between normal aging and a diagnosis of clinically probable Alzheimer's disease (AD). The aMCI construct is particularly useful as it provides an opportunity to assess a clinical stage which in most subjects represents prodromal AD. The aim of this study was to assess the progression of cerebral atrophy over multiple serial MRI during the period from aMCI to progression to AD. Thirty-three subjects were selected that fulfilled clinical criteria for aMCI and had three serial MRI scans: the first scan approximately 3 years before the diagnosis of AD, the second scan approximately 1 year before, and the third scan at the time of the diagnosis of AD. A group of 33 healthy controls were age and gender-matched to the study cohort. Voxel-based morphometry (VBM) was used to assess patterns of grey matter atrophy in the aMCI subjects at each time-point compared to the control group. Customized templates and prior probability maps were used to avoid normalization and segmentation bias. The pattern of grey matter loss in the aMCI subject scans that were 3 years before the diagnosis of AD was focused primarily on the medial temporal lobes, including the amygdala, anterior hippocampus and entorhinal cortex, with some additional involvement of the fusiform gyrus, compared to controls. The extent and magnitude of the cerebral atrophy further progressed by the time the subjects were 1 year before the diagnosis of AD. At this point atrophy in the temporal lobes spread to include the middle temporal gyrus, and extended into more posterior regions of the temporal lobe to include the entire extent of the hippocampus. The parietal lobe also started to become involved. By the time the subjects had progressed to a clinical diagnosis of AD the pattern of grey matter atrophy had become still more widespread with more severe involvement of the medial temporal lobes and the temporoparietal association cortices and, for the first time, substantial involvement of the frontal lobes. This pattern of progression fits well with the Braak and Braak neurofibrillary pathological staging scheme in AD. It suggests that the earliest changes occur in the anterior medial temporal lobe and fusiform gyrus, and that these changes occur at least 3 years before progression to the diagnosis of AD. These results also suggest that 3D patterns of grey matter atrophy may help to predict the time to the first diagnosis of AD in subjects with aMCI.
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Affiliation(s)
- Jennifer L Whitwell
- Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA
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Anderson VC, Litvack ZN, Kaye JA. Magnetic resonance approaches to brain aging and Alzheimer disease-associated neuropathology. Top Magn Reson Imaging 2007; 16:439-52. [PMID: 17088693 DOI: 10.1097/01.rmr.0000245458.05654.d0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The noninvasive, nonradioactive, quantitative nature of magnetic resonance techniques has propelled them to the forefront of neuroscience and neuropsychiatric research. In particular, recent advances have confirmed their enormous potential in patients with Alzheimer disease (AD). Structural and functional magnetic resonance (MR) imaging have demonstrated significant correlation with clinical outcomes and underlying pathology and are used increasingly in the AD clinic. This review will highlight the role of high-resolution structural MR imaging and functional magnetic resonance imaging in the identification of atrophic and hemodynamic changes in AD and their potential as diagnostic biomarkers and surrogates of therapeutic response. Advanced MR techniques based on diffusion, perfusion, and neurochemical abnormalities in the aging brain will be presented briefly. These newer techniques continue to expand our understanding of neuropathology in the aging brain and are likely to play an important clinical role in the future.
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Affiliation(s)
- Valerie C Anderson
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR 97239, USA.
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