Fig. 1: Correlation analysis between SD50 values and clinical parameters of PD progression.

Scatter plots indicating the correlation between log10SD50/ml values and selected clinical or demographic variables: age at sampling (a), MoCA score (b), UPDRS part III score (c) and Hoehn and Yahr score (d). Blue dots represent single observations. Red lines are derived from univariable linear regression models. Correlation coefficients (Rho) and p values are reported in each graph. Abbreviations: H&Y Hoehn and Yahr, MoCA Montreal Cognitive Assessment, UPDRS III Unified Parkinson’s Disease Rating Scale part III.