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Elias-Sonnenschein L.S.,Maastricht University | Bertram L.,Max Planck Institute for Molecular Genetics | Visser P.J.,Maastricht University | Visser P.J.,Alzheimer Center
Biomarkers in Medicine | Year: 2012

Alzheimers disease (AD) is a neurodegenerative disorder characterized by neuritic plaques (main constituent: -amyloid [A]) and neurofibrillary tangles (hyperphosphorylated tau protein) in the brain. Abnormalities in A and tau can be measured upon neuropathological examination, in cerebrospinal fluid or by PET. Etiologically, a growing body of evidence suggests that susceptibility to AD is genetically controlled. However, the precise nature of the underlying risk genes and their relation to AD biomarkers remains largely elusive. To this end, we performed a qualitative review of 17 studies (covering 47 polymorphisms in 26 genes) and investigated the potential relation between the most compelling AD risk genes and markers for A and tau in cerebrospinal fluid, PET imaging and neuropathological examination. Of all covered genes, only APOE and PICALM showed consistent effects on A but not on tau, while no obvious effects were observed for CLU, CR1, ACE, SORL and MAPT. © 2012 Future Medicine Ltd. Source

Passafiume D.,University of LAquila | De Federicis L.S.,University of LAquila | Carbone G.,Alzheimer Center | Giacomo D.D.,University of LAquila
Applied Neuropsychology | Year: 2012

Deterioration of semantic memory is one of the primary neuropsychological deficits caused by Alzheimer's disease (AD). In this study, we hypothesize that the breakdown of semantic memory in the mild-to-moderate stage of AD is due to the disruption of the semantic network that links the concepts. Furthermore, the loss of these links is not homogeneous through the semantic association categories (i.e., Superordinate, Contiguity, Part/Whole, Attribute, Function). Twenty-two subjects (11 patients with mild-to-moderate dementia and 11 control subjects matched on demographics) participated in the study. Both controls and patients with AD underwent extensive neuropsychological evaluation and three experimental tasks: (1) Naming Task, (2) Semantic Association Task, and (3) Semantic Knowledge Task. Results showed that: (1) The AD group was significantly different from the normal controls group in all the experimental tasks; (2) the Semantic Association Task was significantly worse than the other tasks; (3) for the AD group, the scores of the Function and Part/Whole association categories were higher than in the other categories; and (4) living stimuli were more impaired than nonliving. These data confirm prior research showing the semantic association is differently impaired in AD patients. Copyright © Taylor and Francis Group, LLC. Source

Perez G.,Technical University of Ambato | Perez G.,Rey Juan Carlos University | Conci A.,Federal University of Fluminense | Moreno A.B.,Rey Juan Carlos University | Hernandez-Tamames J.A.,Alzheimer Center
Integrated Computer-Aided Engineering | Year: 2014

Preprocessing stage for denoising is a crucial task in image analysis in general, and in computer-aided diagnosis using medical images in particular. Standard acquisition of Magnetic Resonance Images (MRI) presents statistical Rician noise which degrades the performance of the image analysis. This paper presents a new technique to reduce Rician noise of brain MRI. The new method for noise filtering is achieved in the discrete Wavelet Packets Transform (WPT) domain. Four methodologies for thresholding the detail coefficients in the same 2D WPT domain have been experimented considering two scenarios (with and without a previous adaptive Wiener filtering in the spatial domain). Best quantitative and qualitative results have been obtained by the new method presented in this work (specifically tailored for brain MRI), which is adaptive to each subband and dependent on the data. It has been compared with other traditional methods considering the Signal to Noise Ratio (SNR), Normalized Cross Correlation (NCC) and execution time ( 0.1 s/slice). A complete dataset of structural (T1-w) brain MRI of the BrainWeb database has been used for experiments. An important aspect is that these experiments with synthetic images proved that the common prior adaptive Wiener filtering often used by many authors is a dispensable procedure. © 2014 IOS Press. Source

Fiala M.,University of California at Los Angeles | Veerhuis R.,Alzheimer Center
Experimental Gerontology | Year: 2010

The ultimate goal of diagnostic research is a blood test detecting the risk of Alzheimer disease (AD) before neuronal damage develops. Current amyloid-β (Aβ) tests do not detect the process leading to neurodegeneration. Novel immunologic and proteomics tests are based on aberrant appearance of inflammatory cytokines in the CSF and other protein biomarkers in the CSF or blood, and immune biomarkers of peripheral blood mononuclear cells (PBMC's). Cytokines, chemokines, complement factors, serum amyloid P component, and signaling proteins in the CSF or blood may be a rich source of diagnostic biomarkers, but the power of these tests will need to be examined in prospective studies. Recently-described flow cytometric test of defective Aβ phagocytosis detects patients with AD with a high sensitivity and specificity in distinct populations (confirmed AD patients vs. active University professors), but further experience is necessary for its use in general population at risk of AD. The analysis of the transcriptome of peripheral blood mononuclear cells "stressed" by Aβ is beginning to unravel the relations between specific pathways and AD. Thus novel diagnostic tests may provide biomarkers for pre-clinical detection, clarification of progression from MCI to AD, and follow-up of patients in clinical trials of immunostimulating therapies. © 2009 Elsevier Inc. All rights reserved. Source

Bakker C.,Center for Specialized Care in Early Onset Dementia | Bakker C.,Radboud University Nijmegen | De Vugt M.E.,Maastricht University | Van Vliet D.,Maastricht University | And 5 more authors.
American Journal of Geriatric Psychiatry | Year: 2013

Objective: Early onset dementia (EOD) poses specific challenges and issues for both the patient and (in)formal care. This study explores the use of (in)formal care prior to institutionalization, and its association with patient and caregiver characteristics. Design/Setting: Participants were part of a community-based prospective longitudinal study of 215 patients and their informal caregivers. Participants: Baseline data of a subsample of 215 patient-caregiver dyads were analyzed. Measurements: Analyses of covariance were performed to determine correlates of (in)formal care use assessed with the Resource Utilization in Dementia (RUD)-Lite questionnaire. Results: Informal care had a 3:1 ratio with formal care. Supervision/surveillance constituted the largest part of informal care. In more than half of cases, patients had only one informal caregiver. The amount of informal care was associated with disease severity, showing more informal care hours in advanced disease stages. Fewer informal care hours were related to more caregiver working hours, especially in younger patients. The amount of formal care was related to disease severity, behavioral problems, and initiative for activities of daily living. Conclusion: In EOD, it appears that family members provide most of the care. However, other social roles still have to be fulfilled. Especially in spousal caregivers of younger patients in advanced disease stages, there is a double burden of work and care responsibilities. This finding also indicates that even within the EOD group there might be important age-related differences. The relatively higher amount of formal care use during advanced disease stages suggests a postponement in the use of formal care. © 2013 American Association for Geriatric Psychiatry. Source

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