The first objective is to asses influence of age on amyloid load measured by PET imaging using Pittsburgh B compound (PiB) radio-tracer, in Alzheimer's disease(AD). This will allow the determination of brains age-specific deterioration factors by comparing Early onset AD (EOAD), Late onset AD (LOAD)and atypical focal cortical AD (PCA and LPA). The amount of brain lesions in AD patients is estimated by: 1. measuring the rate of cortical brain atrophy, 2. FDG imaging of glucose metabolism reflecting neuronal activity, and 3. for patients who benefited from a lumbar puncture; Cortical-spinal fluid (CSF) amounts of amyloïd and tau proteins are measured.
Literature data suggests there are different types of AD depending on their age of onset, called EOAD and LOAD. These two categories are distinguished by the localization of brain atrophy : severe and 'posterior' in EOAD and more 'anterior' in LOAD. Neuro-pathologic data suggests some atypical focal cortical atrophy, characterized by a respect of episodic memory, may be classified within EOAD. PiB-based PET imaging allows the in-vivo visualization and quantification of amyloïd load. We want to answer the question whether the amount of amyloïd protein may be lower in LOAD than EOAD in patients showing the same level of dementia, and thus identify ageing-specific cognitive disorders and understand witch factors influence etio-pathology of typical and atypical Alzheimer's disease.
Study Type
OBSERVATIONAL
Enrollment
60
Pitie Salpêtrière Hospital
Paris, Île-de-France Region, France
PIB-PET imaging of amyloid load
PET imaging using PIB radio-tracer will give an estimation of regional amyloid load for every patient
Time frame: 0 - 2 months
FDG-PET imaging of glucose metabolism
PET imaging using 18F-fluorodesoxyglucose (FDG) will give a visualization of regional neuronal metabolism
Time frame: 0 - 2 months
clinical phenotypic assessment
the clinical evaluation includes a neurologic consulting, a neuropsychologic assessment of cognitive performances, and evaluation of autonomy
Time frame: 0 - 2 months
MRI
the magnetic resonance imaging will be performed using numerous modalities like T1 weighted sequences for anatomic information, T2 weighted FLAIR and TSE sequences to avoid vascular injuries and T2 GRE to avoid microbleeds, DTI for the diffusion tensor imaging and default mode FMRI, to identify neural networks involved in default concious mode.
Time frame: 0 - 2 months
ApoE gene sequencing
ApoE gene sequencing, will be performed after all samples have been collected. So this may be 0 to 24 month after inclusion.
Time frame: 0 - 24 months after inclusion
amyloid and Tau measurements in cerebro-spinal fluid (csf)
some patients have a lumbar puncture that allows a direct quantification of CSF amyloid, tau and phospho-tau amounts.This measure is performed in the 6 months following the clinical assessment (at inclusion) and when a former puncture has already been done, it can be used retro-actively up to 6 months before clinical assessment.
Time frame: -6 months or +6months arround T0
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