The complex pathological cascades leading to both Alzheimer's disease (AD) and Parkinson's disease (PD) involve, at various points, inflammation. Since inflammation is a treatable symptom, understanding how and when it impacts the brain, and where specifically in the brain, would offer important guidance in the development of new treatments, sorely needed in both diseases. Microglia play an important anti-inflammatory role, and produce a substance, mitochondrial translocator protein (TSPO), whose presence can be used as a marker of regional inflammation. GE180 is a newly developed PET ligand which binds to TSPO and hence can be used in imaging studies to analyze regional inflammation in living patients. In prior studies it has shown regional specificity in multiple sclerosis and brain injury. In the current study, the investigators will be using GE180 to analyze regional and global inflammation in the brains of patients with AD and PD at two time points. The results of the current study will provide enriched understanding of inflammation in these conditions, and potentially provide preliminary data to inform design of future interventional trials.
Name: GE180 PET Scan
Description: We will use a linear regression model to assess whether regional microglial activation is predictive of cognitive performance in domains of memory, visuospatial function, language, and executive functioning. These differing units of measurement collected through neuropsychological evaluation will be aggregated into one model in order to assess the correlations between regional activation and cognitive performance in any different domains.Measure: Linear Regression Model Assessing Cognitive Performance and Regional Microglial Activation Time: Baseline
Description: We will use repeated measures analyses to asses whether there is a significant change in microglial activation between year 1 scan and year 2 scan. We will then assess if this change in microglial activation over this time period relates to changes in cognitive measures.Measure: Repeated Measures Analyses to Asses Change in Microglial Activation Over Time Time: Baseline (Year 1) compared to Year 2
Description: We will use a linear regression model to assess whether global microglial activation is predictive of overall cognitive performance (as assessed with scores on the Dementia Rating Scale (DRS) and Montreal Cognitive Assessment (MoCA)).Measure: Linear Regression Model Assessing Cognitive Performance and Global Microglial Activation Time: Baseline
There is one SNP
For MCI patients, fit criteria based in Movement Disorders Task Force or NIA Exclusion Criteria: 1. Significant neurological disorders other than AD or PD; 2. Unstable medical conditions 3. History of major psychiatric diseases 4. MRI evidence of infarction or other focal lesion or multiple lacunes 5. Clinically significant abnormalities in B12 or TSH 6. Identified as having a common polymorphism (rs6971) in the TSPO gene which has been shown to reduce binding affinity of tracers similar to GE180.