Several clinical tools are available for identification of patients at risk of cardiac arrhythmias or its consequences that may benefit from interventions to reduce morbidity and risk of sudden death. These include noninvasive tests, such as a standard (more…)

The current standard of clinical care for mild to moderate Alzheimer’s Disease is treatment with cholinesterase inhibitors. Four are currently available: donepezil, tacrine, rivastigmine, and galantamine. These treatments may slow cognitive decline or may reduce the emergence of new behavioral manifestations of the disease but are not considered a cure for the disease. Nevertheless, the prevalence and importance of understanding the physiological effects of these drugs in the treatment of Alzheimer’s Disease is not to be underestimated. (more…)

An alternate approach to imaging brain function in Alzheimer’s Disease uses activation imaging, in which subjects perform a cognitive task, such as a memory test, in comparison to a control or resting state, during scanning. These methods identify brain regions that show increased cerebral blood flow (CBF), which is tightly coupled to neural activity, during ongoing mental operations. In principle, brain regions with impaired neural activity will show less CBF when engaged in a task than those unaffected and have the potential for identifying deficits more sensitively. In practice, however, activation imaging is more complicated: first, PET ligands used in activation imaging, typically H 2 [15-O], have a short half life, necessary for experiments involving multiple conditions but producing images with significantly lower signal, (more…)

There is a keen interest in developing more direct measures of Alzheimer’s Disease-specific pathology, which has led to the emergence of several new PET ligands to measure amyloid deposition. Amyloid plaques, which are composed of Ab, and neurofibrillary tangles (NFTs) are the pathological hallmarks of Alzheimer’s Disease. NFTs are correlated with the stage of Alzheimer’s Disease, and both pathological deposits appear before symptoms show themselves, perhaps decades before. This observation using amyloid imaging suggests that these deposits may be a good early marker for the disease. Based on the presence of diffuse plaques in neurologically normal individuals, it may be that Ab accumulation precedes other pathological features of Alzheimer’s Disease. (more…)