Parkinson's disease is a progressive neurodegenerative disease affecting almost 2% of the population over 65. The disease is characterized by motor symptoms such as bradykinesia, rigidity, resting tremor, postural instability and non-motor symptoms such as cognitive dysfunction, depressed mood, nocturnal sleep problems, daytime somnolence and autonomic disturbances. Parkinson's disease is not a single disease; epidemiological, genetic and experimental studies suggest that environmental and genetic factors that compromise processes fundamental to neuronal vitality may contribute to the pathobiology of this disorder. Patients with Parkinson's disease do not follow a uniform disease course, but exhibit conspicuous differences in the profile of primary disease-related and medication-induced complications as well as in the rate of progression of the disease, reflecting the existence of subtypes.
In the past our group had a strong focus on characterizing those aspects of the disease that are important for research and management.
This work has led to the development of a set of clinimetric sound measurement instruments: the SCOPA-scales. In a subsequent project these instruments were used to follow patients in a longitudinal cohort study, the PROPARK (PROfiling PARKinson's disease) study. This has resulted in the establishment of an extensive database of over 400 well-characterized patients which, in turn, formed the basis for several projects on clinical characterization, inter-relations between clinical domains, the identification of subgroups of the disease, and phenotype-genotype relations. Additionally, the cohort participated in in several candidate-gene and genome-wide association studies.
Currently, the Leiden group is focusing on predictors of motor and nonmotor manifestations of the disease, on methods to improve phenotype characterization and subtype identification, and on potential radiological and molecular biomarkers of the disease.