Correlation between the Movement Disorders Society Unified Parkinson's Disease rating scale (MDS-UPDRS) and the Unified Parkinson's Disease rating scale (UPDRS) during L-dopa acute challenge.

While Movement Disorders Society Unified Parkinson's Disease rating scale (MDS-UPDRS) validation has been exhaustive; performance evaluation to detect acute changes arising after administration of a single dose of L-dopa has yet to be explored. To determine the correlation between UPDRS and MDS-UPDRS during the acute challenge with Ldopa and the MDS-UPDRS equivalent to 30% cutoff score of UPDRS for defining responsiveness, 64 patients were assessed. Consecutive assessments were performed immediately before and after administration of a single dose of L-dopa/carbidopa 250/25 mg using the motor section of the UPDRS and the MDS-UPDRS. Good diagnostic accuracy, consistent with published findings of high correlation between scales was observed. Area under the curve (AUC) was 0.99 (CI = 0.97-1.00, P < 0.001) and maximum Youden index (Y = 0.905) corresponded to a cutoff of 24.5%. In conclusion we have found an excellent correlation between UPDRS and MDS-UPDRS and that the 30% of variation in UPDRS score used for predicting sustained long term L-dopa response was equivalent to 24% in MDS-UPDRS.