The purpose of this study is to determine the potential for a Parkinson's Disease (PD) -specific breath signature as a non-invasive screening tool for identifying PD patients with inflammation, tracking the progression of disease, and responsiveness to various therapeutic interventions, in particular anti-inflammatory or immunomodulatory therapies. Neurological disorders include any disorder involving the brain or the nervous system, for example memory disorders, stroke, movement disorders and many other conditions.