Alzheimer's Disease Neuroimaging Initiative Grand Opportunity

This project continues the work from ADNI1, the goal of which is to test whether serial magnetic resonance imaging (MRI), positron emission tomography (PET), other biological markers, and clinical and neuropsychological assessments can be combined to measure the progression of mild cognitive impairment (MCI) and early Alzheimer's disease (AD). The goal of the study is to determine relationships among the clinical, cognitive, imaging, genetic, and biochemical biomarker characteristics of the stage of the AD spectrum that precedes MCI, the mildest symptomatic phase of AD, referred to here as EMCI. The ADNI-GO model posits that AD begins with amyloid β (Aβ) deposition in the cortex, which leads to synaptic dysfunction, neurodegeneration, and cognitive/ functional decline. Some of the leading-edge technologies under study are brain-imaging techniques, such as positron emission tomography (PET), including FDG-PET (which measures glucose metabolism in the brain); PET using a radioactive compound (F-AV-45) that measures brain beta-amyloid; and structural MRI. Brain scans are showing scientists how the brain's structure and function change as AD starts and progresses. Biomarkers in cerebrospinal fluid are revealing other changes that could identify which patients with MCI will develop Alzheimer's. Scientists are looking at levels of beta-amyloid and tau in cerebrospinal fluid. (Abnormal amounts of the amyloid and tau proteins in the brain are hallmarks of Alzheimer's disease.) All participants from ADNI1 who are in the normal and MCI stages will continue to be followed in ADNI-GO. The next step is to scan and analyze the brains of people with EMCI; 200 EMCI participants will be enrolled to narrow the gap between cognitively normal (CN) and "late MCI (LMCI)" participants currently enrolled in ADNI. The overall impact of this study will be increased knowledge concerning the sequence and timing of events leading to MCI and AD, development of better clinical and imaging/fluid biomarker methods for early detection and for monitoring the progression of these conditions, and facilitation of clinical trials of treatments to slow disease progression, ultimately contributing to the prevention of AD.