On the correlation between UPDRS scoring in the leg agility, sit-to-stand, and gait tasks for parkinsonians

Recently, we have proposed a unified approach, based on the use of a Body Sensor Network (BSN) formed by a few body-worn wireless inertial nodes, for automatic assignment of Unified Parkinsons Disease Rating Scale (UPDRS) scores in the following tasks: Leg Agility (LA), Sit-to-Stand (S2S), and Gait (G). Unlike our previous works and the majority of the works appeared in the literature, where UPDRS tasks are investigated singularly, in the current paper we carry out a comparative investigation of the LA, S2S, and G tasks. In particular, we focus on the correlation between UPDRS values assigned to the three tasks by both an expert neurologist and our automatic system. We also consider an aggregate UPDRS score in order to highlight the relevance of each task in the assessment of the gravity of the Parkinson;s Disease (PD).