The Vall d'Hebron Initiative for Parkinson (VHIP) cohort: a prospective, longitudinal, and observational study enrolling de novo Parkinson's disease patients for biomarker identification and validation.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder causing a variety of motor and non-motor symptoms. To date, no disease modifying treatment exists, and diagnosis is based on the manifestation of the clinical motor symptoms, which occurs when the neurodegenerative process is already advanced. Studies designed to find diagnostic/prognostic biomarkers and pathophysiological pathways involved in disease onset/progression are needed. OBJECTIVE: To describe the study protocol of the Vall d'Hebron Initiative for Parkinson (VHIP) Cohort, a prospective and longitudinal observational cohort study aimed at deeply phenotyping de novo PD patients, including carriers of PD-linked mutations. We anticipate this initiative will contribute to identifying biomarkers for PD risk, diagnosis, and prognosis, as well as to stratify disease subtypes and increase our understanding of pathophysiology at early disease stages. METHODS/DESIGN: Subjects are prospectively recruited by movement disorder specialists at the Vall d'Hebron University Hospital (VHUH). To date, the study cohort includes 174 subjects-consisting of 117 patients with de novo Parkinson's disease, 17 individuals with REM sleep behavior disorder (RBD), and 33 healthy controls-and recruitment is still ongoing. After informed consent, subjects are evaluated in detail to primarily assess objectives within four major domains of PD: motor, cognitive-affective, autonomic function, and vision. This includes first an extensive clinical evaluation (i) recording demographic, personal history, lifestyle, and dietary habits and (ii) performing clinical scales covering motor and non-motor symptoms. Second, data from autonomic function and visual function tests, together with neuroimaging data, are acquired. And finally, a wide range of biospecimens are collected for biochemical and molecular assessments including the genotyping of all participants. Participants receive follow-up assessments at 2.5 and 5-year intervals. RESULTS/DISCUSSION: VHIP is the first study to establish a Spanish cohort combining clinical, imaging, biochemical and molecular data over time in de novo patients, including PD-linked mutation carriers. VHIP provides a unique opportunity to link pre-diagnosis disturbances to PD development, as well as to identify risk, diagnosis, and prognosis biomarkers. CLINICAL TRIAL REGISTRATION: https://vhir.vallhebron.com/es/investigacion/proyecto-vall-dhebron-iniciativa-para-el-parkinson-vhip.