Introduction and development. Parkinson's disease (PD) is a chronic and progressive disorder. It produces a significant burden not only for patients, but also for their family and caregivers, with a major socio-economic impact on society. Current knowledge on PD is characterized by scarce information about the evolutionary course of: 1) the non-motor PD features; 2) impact of non-motor PD features on disability and health related quality of life (HRQL) impairment; 3) factors related to disability and HRQL determinants; 4) factors that speed or slow the progression of PD; 5) differential long-term effect of available PD therapeutic schedules and their relationships with disability, complications, and HRQL; and 6) impact of the disease on patients' caregivers. In addition, heterogeneity in the metric quality of the applied measures and selection bias are frequently found. Conclusion. Due to the aforementioned limitations and from a multidimensional perspective, a new longitudinal study in PD is deemed necessary. The longitudinal study of PD patients (ELEP) includes a long-term follow-up of never before sistematically assessed aspects, will allow to increase the global knowledge about PD.
