Predictors for mild parkinsonian signs: a prospective population-based study.

Abstract

Mild parkinsonian signs (MPS) are common in the elderly population and are associated with a wide range of adverse health outcomes, including incident Parkinson's disease (PD). We aimed to prospectively evaluate potential risk factors for incident MPS. Participants of the population-based Bruneck Study representative for the general elderly community underwent a baseline assessment of substantia nigra (SN)-echogenicity with transcranial sonography, olfactory function with the Sniffin' Sticks identification test and vascular risk according to the Framingham risk score as well as a baseline and 5-year follow-up neurological examination. MPS were defined according to established criteria based on the entire motor section of the Unified PD Rating Scale. Participants with PD at baseline or follow-up and subjects with MPS at baseline were excluded. A logistic regression analysis adjusted for age and sex was used to detect risk factors for incident MPS in the remaining 393 participants. SN-hyperechogenicity and hyposmia were related to the development of MPS with odds ratios of 2.0 (95%CI, 1.1-3.7) and 1.6 (95%CI, 1.0-2.7), respectively, while increased vascular risk was not. Having both, SN-hyperechogenicity and hyposmia, was associated with an odds ratio of 3.0 (95%CI, 1.2-7.7) for incident MPS. Among the various motor domains, increased SN-echogenicity predicted the development of bradykinesia and rigidity, whereas diminished olfactory function predicted the development of impaired axial motor function. In addition to their established roles as risk factors for PD, SN-hyperechogenicity and hyposmia are associated with an increased risk for MPS in the general elderly community.