[A longitudinal study of patients with Parkinson's disease (ELEP): aims and methodology].

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 systematically assessed aspects, will allow to increase the global knowledge about PD.