Research on the premotor symptoms of Parkinson's disease: clinical and etiological implications.

BACKGROUND: The etiology and natural history of Parkinson's disease (PD) are not well understood. Some non-motor symptoms such as hyposmia, rapid eye movement sleep behavior disorder, and constipation may develop during the prodromal stage of PD and precede PD diagnosis by years. OBJECTIVES: We examined the promise and pitfalls of research on premotor symptoms of PD and developed priorities and strategies to understand their clinical and etiological implications. METHODS: This review was based on a workshop, Parkinson's Disease Premotor Symptom Symposium, held 7-8 June 2012 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. DISCUSSION: Research on premotor symptoms of PD may offer an excellent opportunity to characterize high-risk populations and to better understand PD etiology. Such research may lead to evaluation of novel etiological hypotheses such as the possibility that environmental toxicants or viruses may initiate PD pathogenesis in the gastrointestinal tract or olfactory bulb. At present, our understanding of premotor symptoms of PD is in its infancy and faces many obstacles. These symptoms are often not specific to PD and have low positive predictive value for early PD diagnosis. Further, the pathological bases and biological mechanisms of these premotor symptoms and their relevance to PD pathogenesis are poorly understood. CONCLUSION: This is an emerging research area with important data gaps to be filled. Future research is needed to understand the prevalence of multiple premotor symptoms and their etiological relevance to PD. Animal experiments and mechanistic studies will further understanding of the biology of these premotor symptoms and test novel etiological hypothesis.

Funding agencies and disease organizations: resources and recommendations to facilitate ALS clinical research.

Ten groups presented their perspectives on facilitating clinical research in ALS including four federal agencies, four disease organizations, one foundation and one advocacy group. The federal agencies (National Institute of Neurological Disorders and Stroke, National Institute of Environmental Health Sciences, Office of Rare Diseases Research, Department of Defense) encourage fostering a team approach between pre-clinical and clinical research investigators, coordinating with patient groups in the early phases of clinical studies, enhancing private and public partnerships, and investigating the interplay between genetic susceptibility and environmental exposure. The disease organizations (Muscular Dystrophy Association, ALS Association, ALS Society of Canada, and the Motor Neurone Disease Association UK) support fellowship training programs to develop ALS clinician scientists, and encourage work on the epidemiology of ALS, on genetic and epigenetic mechanisms that are relevant to ALS pathogenesis, on developing ALS registries and biobanks, and building bridges of collaboration among study groups. The Foundation supports innovative projects, including stem-cell research, and Patient Advocacy is committed to supporting excellence in ALS research and patient care, and believes strongly in enhancing communication between patients and members of the research community.

The outdoor air pollution and brain health workshop.

Accumulating evidence suggests that outdoor air pollution may have a significant impact on central nervous system (CNS) health and disease. To address this issue, the National Institute of Environmental Health Sciences/National Institute of Health convened a panel of research scientists that was assigned the task of identifying research gaps and priority goals essential for advancing this growing field and addressing an emerging human health concern. Here, we review recent findings that have established the effects of inhaled air pollutants in the brain, explore the potential mechanisms driving these phenomena, and discuss the recommended research priorities/approaches that were identified by the panel.

Genetic aspects of behavioral neurotoxicology.

Considerable progress has been made over the past couple of decades concerning the molecular bases of neurobehavioral function and dysfunction. The field of neurobehavioral genetics is becoming mature. Genetic factors contributing to neurologic diseases such as Alzheimer's disease have been found and evidence for genetic factors contributing to other diseases such as schizophrenia and autism are likely. This genetic approach can also benefit the field of behavioral neurotoxicology. It is clear that there is substantial heterogeneity of response with behavioral impairments resulting from neurotoxicants. Many factors contribute to differential sensitivity, but it is likely that genetic variability plays a prominent role. Important discoveries concerning genetics and behavioral neurotoxicity are being made on a broad front from work with invertebrate and piscine mutant models to classic mouse knockout models and human epidemiologic studies of polymorphisms. Discovering genetic factors of susceptibility to neurobehavioral toxicity not only helps identify those at special risk, it also advances our understanding of the mechanisms by which toxicants impair neurobehavioral function in the larger population. This symposium organized by Edward Levin and Annette Kirshner, brought together researchers from the laboratories of Michael Aschner, Douglas Ruden, Ulrike Heberlein, Edward Levin and Kathleen Welsh-Bohmer conducting studies with Caenorhabditis elegans, Drosophila, fish, rodents and humans studies to determine the role of genetic factors in susceptibility to behavioral impairment from neurotoxic exposure.