In Patients With Parkinson's Disease Dementia, New Findings, Imaging May Aid Diagnosis Of Concomitant AD
Dementia is a frequent complication of Parkinson's disease (PD), but it is clinically impossible to distinguish PD dementia (PDD), which develops from the progression of the Lewy body pathology that underlies PD, from PD with coexistent Alzheimer's disease (PDAD). Both have similar characteristics. A team of scientists has found that PDAD patients have much denser accumulations of amyloid plaques in the striatal area of the brain than PDD patients. The results suggest that recently developed imaging techniques may be able to identify striatal amyloid plaques in the living brain and could be useful for distinguishing PDD from PDAD. Their results are published in the April issue of the Journal of Parkinson's Disease. "We sought to determine if the presence, density, or type of striatal plaques were predictive of the presence of a clinicopathological diagnosis of Alzheimer's disease in subjects with PD and dementia, " say lead investigators Thomas G.
Shrinkage of the hippocampus occurs with age and is caused by the cumulative effect of various factors. Hippocampal atrophy is a recognized biological marker of Alzheimer's disease, so it is vital that researchers determine the cause of this process. An international study under the French leadership of Christophe Tzourio looked for genetic variabilities linked to the shrinkage of the hippocampus. To do this, the genomes and MRI scan data of over 9000 persons aged between 56 and 84 were analyzed with a view to detecting a potential link between certain mutations and the reduction in the hippocampal volume. The participants' data (both subjects presenting dementia and healthy subjects) were extracted from eight cohort studies in Europe and in North America. The researchers first identified 46 differences in the DNA sequences of the participants, thought to be related to a reduction in the volume of the hippocampus.
According to GE Healthcare, the preliminary results of two Phase 3 studies of their investigational PET amyloid-imaging agent, [18F]flutemetamol, a GE Healthcare PET imaging agent developed to detect beta amyloid, both met their primary endpoints. Full results of both studies will be presented in the near future. One of the studies involved terminally ill patients, who agreed to undergo brain autopsy, displaying strong association between flutemetamol PET images and beta amyloid brain pathology linked to Alzheimer's disease (AD), whilst the other study was performed in young, healthy volunteers below the age of 40 years, and achieved similar results with the known lack of brain amyloid in this population. Carl Sadowsky, MD, Clinical Professor of Neurology at Nova Southeastern University Ft.
In the March 22 edition of Neuron, researchers at the San Francisco VA Medical Center and the University of California, San Francisco, reveal that a new magnetic resonance imaging (MRI) technique based on whole-brain tractography that maps the "communication wires" (neural pathways) that connect different regions of the brain, may predict the rate of progression and physical path of many degenerative brain diseases. The technique was developed by SFVAMC researchers together with a team led by Bruce Miller, M.D., clinical director of the UCSF Memory and Aging Center. According to the researchers, the new technique supports growing evidence that dementias spread through the brain along specific neuronal pathways in the same way as prion diseases do. Using images of 14 healthy brains, the researchers used the technique to realistically predict the physical progression of Alzheimer's disease and frontotemporal dementia (FTD).
Versions Of 4 Genes Found To Impact Memory In Adults: Study Has Implications For Alzheimer's Disease
Two research studies, co-led by UC Davis neurologist Charles DeCarli and conducted by an international team that included more than 80 scientists at 71 institutions in eight countries, has advanced understanding of the genetic components of Alzheimer's disease and of brain development. Both studies appear in the journal Nature Genetics. The first study, based on a genetic analysis of more than 9, 000 people, has found that certain versions of four genes may speed shrinkage of a brain region involved in making new memories. The brain area, known as the hippocampus, normally shrinks with age, but if the process speeds up, it could increase vulnerability to Alzheimer's disease, the research suggests. The second paper identifies two genes associated with intracranial volume - the space within the skull occupied by the brain when the brain is fully developed in a person's lifespan, usually around age 20.