The Parkinson's Disease Composite Scale Is Adequately Responsive to Acute Levodopa Challenge

Abstract

Background: The Parkinson's Disease Composite Scale (PDCS) is a recently developed easy-to-use tool enabling a timely but comprehensive assessment of Parkinson's disease (PD)-related symptoms. Although the PDCS has been extensively validated, its responsiveness to acute levodopa challenge has not been demonstrated yet. Objective: To investigate the correlation between changes in the motor examination part of the Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and the PDCS motor scores during acute levodopa challenge and calculate a cutoff range on the PDCS indicating clinically relevant improvement. Methods: A consecutive series of 100 patients with parkinsonism were assessed using the motor examination sections of the MDS-UPDRS and the PDCS at least 12 hours after the last levodopa dose and after the administration of a single dose of a suprathreshold immediate formulation of levodopa/benserazide reaching the "best ON." Results. There was a high correlation between changes in the MDS-UPDRS and the PDCS motor scores (Spearman's rho = 0.73, p < 0.001). Receiver operating characteristic analysis revealed that a 14.6%-18.5% improvement in the PDCS motor scores corresponds to a 20-30% improvement in the MDS-UPDRS motor examination. Conclusions: The PDCS can reliably and adequately respond to an acute levodopa challenge. Any improvements in PDCS motor scores exceeding the 14.6-18.5% threshold could represent a clinically relevant response to levodopa.