Validation of the Portuguese MDS-UPDRS: Challenges to Obtain a Scale Applicable to Different Linguistic Cultures.

Background: The MDS-UPDRS has been available in English since 2008, showing satisfactory clinimetric results and being proposed as the new official benchmark scale for Parkinson's disease (PD), being cited as a core instrument for PD in the National Institutes of Neurological Disorders and Stroke Common Data Elements program. For this reason, the MDS created guidelines for development of MDS-UPDRS official, clinimetrically validated translations.

Objective: This study presents the formal process used to obtain the officially approved Portuguese version of the MDS-UPDRS.

Handicap as a Measure of Perceived-Health Status in Parkinson's Disease.

Background: Handicap is a patient-centered measure of health status that encompasses the impact of social and physical environment on daily living, having been assessed in advanced and late-stage Parkinson's Disease (PD).

Objective: To characterize the handicap of a broader sample of patients.

Methods: A cross-sectional study of 405 PD patients during the MDS-UPDRS Portuguese validation study, using the MDS-UPDRS, Unified Dyskinesias Rating Scale, Nonmotor symptoms questionnaire, PDQ-8 and EQ-5D-3L.

Semiclassical propagation of Gaussian wave packets.

We analyze the semiclassical evolution of Gaussian wave packets in chaotic systems. We show that after some short time a Gaussian wave packet becomes a primitive WKB state. From then on, the state can be propagated using the standard time-dependent WKB scheme.

Lyapunov exponent of many-particle systems: testing the stochastic approach.

The stochastic approach to the determination of the largest Lyapunov exponent of a many-particle system is tested in the so-called mean-field XY Hamiltonians. In weakly chaotic regimes, the stochastic approach relates the Lyapunov exponent to a few statistical properties of the Hessian matrix of the interaction, which can be calculated as suitable thermal averages. We have verified that there is a satisfactory quantitative agreement between theory and simulations in the disordered phases of the XY models, either with attractive or repulsive interactions.