Patterns of Motor and Non-Motor Features in Medication-Naïve Parkinsonism

Parkinsonism is defined by motor features (tremor, bradykinesia, rigidity, and postural instability). Accompanying non-motor features (e.g. cognitive, autonomic, sleep disturbances) are underrecognized and undertreated. We hypothesized that clinical patterns occurring in early, medication-naïve Parkinsonism are distinguished by features such as tremor, sleep, autonomic, and cognitive dysfunction.

Clinical and neuroimaging data were obtained in the Parkinson's Progression Marker Initiative. Group comparisons of Parkinsonism with dopaminergic deficits (PDD) (n = 388), controls (n = 196), and Parkinsonism with scans without evidence of dopaminergic deficits (n = 64) were done with ANOVA, chi-square, and post-hoc pairwise tests. To examine clinical patterns within the PDD group, k-means clustering was performed with non-motor or motor features, or both.

Among PDD, 4 non-motor patterns (% of PDD) (impulsive (14.9%), sleep-autonomic (22.9%), cognitive-olfactory (18.0%), and mild (44.1%)), 4 motor patterns (tremor plus bradykinesia (56.2%), tremor without bradykinesia (16.2%), postural instability (6.7%) and no tremor (20.9%)) and 5 combined motor/non-motor patterns (tremor with bradykinesia (42.3%), tremor without bradykinesia (15.5%), no tremor and mild non-motor features (17.0%), postural instability with sleep-autonomic disturbances (6.7%) and oldest onset cognitive-olfactory (18.6%)) were observed.

To our knowledge, this is the first description of non-motor clinical patterns in early, medication-naïve Parkinsonism, suggesting that such features are intrinsic to Parkinsonian disorders.