Objective: To identify clinical signs that determine a phenotypic heterogeneity of idiopathic Parkinson's disease (PD) using cluster analysis.
Material and methods: Cluster analysis was applied to main clinical signs characteristic of disease course and to the results of examination of 72 PD patients based on 5 scales.
Results: Clinical signs that determine a phenotypic heterogeneity of PD were identified. The most significant variables were a form of disease, predominance of akinetic/rigid syndrome or tremor syndrome as well as the age at disease onset, severity of motor deficit and autonomic symptoms.
Conclusion: The definition "a form of PD" has a wider meaning compared to established one. To determine a form of disease, we recommend to consider both the predominance of a definite motor symptom and a set of additional clinical parameters.