Pairwise correlations were computed between all variables. In addition, given the large covariation between spectral power and PAC, we also performed a multiple regression analysis with contralateral bradykinesia/rigidity UPDRS scores as independent variable and beta band power, HFO power, and PAC as predictors. Analyses were repeated for the difference between OFF and ON states (OFF–ON), meaning that we directly correlated the clinical improvement obtained after levodopa administration with the observed change in spectral power and PAC measures. For this, we could only include patients with both OFF and ON recordings available, leaving 38 STN sites from 19 subjects.
