Fig. 4

Fluorescence-dye-labeled sEV. A Correlation coefficient analysis between fluorescence-dye-labeled sEV concentration with α-synuclein protein levels (p = 0.0416), “r” represents the correlation coefficient. B Tabular representation of the correlation between the fluorescence-dye-labeled sEV concentration and age, α-synuclein protein levels, UPDRS scores, H&Y scores, and duration of the disease. Quantification of salivary sEV concentration of prodromal PD and HC: salivary sEV levels from HC and prodromal PD are represented in NTA of scatter mode (p = 0.01) (C); and fluorescence-dye mode (p = 0.008) (D). Similarly, E alpha-synuclein protein determination from sEV of HC and prodromal PD cases (p = 0.02). All graphs are presented with mean ± SEM