PET Imaging Study of Neurochemical and Autonomic Disorders in Multiple System Atrophy (MSA)

Multiple system atrophy (MSA) is a disorder of the nervous system of unclear cause. In MSA there is degeneration (progressive loss) of nerve cells in several brain and spinal cord regions. The result is a variety of symptoms, from physical (parkinsonism, ataxia, incoordination, falls, slowness) to autonomic (fainting, bladder incontinence, sexual dysfunction) to sleep problems (dream enactment, sleep apnea). This research aims to help us better understand the patterns and timing of nerve degeneration relatively early in the disease, and how this affects symptoms and progression. For instance: 1. Does MSA affect certain nerves that stimulate heart pumping? If so, does the severity of loss of heart nerves affect disease progression and survival? 2. It is thought that MSA does not affect memory and thinking much, unlike other diseases (such as Parkinson's). Is this accurate? Is there loss of nerves that transmit acetylcholine (a neurochemical important in mental functioning)? 3. What can we learn about mood and sleep in MSA, through visualizing the serotonin system in the brain? How does this relate to symptoms that subjects report in these often underappreciated areas? To answer these and other questions, investigators will take images of specific nerves in the brain and heart using Positron Emission Tomography (PET) scans. Such imaging gives us information that cannot be obtained from MRIs and CT scans. We will measure the levels of several nerve cell types: serotonin, acetylcholine, and norepinephrine. Subjects will also have many standardized assessments including quality-of-life and symptom assessments, neurological examination, autonomic assessments, neuropsychological assessments, coordination tests, and even assessments of vision and sense of smell. By pooling these results from many MSA patients, and comparing with other diseases (such as Parkinson's disease) we hope to gain a better understanding of what is happening early in MSA. Such knowledge could be v