*4.2. Experimental Setup*

An experimental setup has been built both to assess the accuracy of the system and to acquire relevant clinical and kinematic data useful for the automated assessment of the UPDRS tasks. The kinematic parameters evaluated by the system were compared with those evaluated by an optoelectronic system, considered as gold reference (BTS SMART DX400©, eight TVC, 100–300 fps, BTS Bioengineering, Milan, Italy) [48]. For this experiment, reflective markers were attached to the body of the PD and HC subjects to evaluate kinematics of lower limbs, thorax, spine and head (Figure 4). The biomechanical measurements of the lower body were modelled according to the Helen Hayes Marker set [49,50] and those of the upper body were modelled according to the Plug In Gait model (Vicon® Motion Systems, Oxford, UK) [51], focusing the attention only on thorax, shoulders and spine. Three additional markers were put on the forehead (MHEAD), on the right (MRWRS) and the left wrist (MLWRS) respectively, this to allow for the assessment of the head posture, CoM estimation and data synchronization between our system and the optoelectronic system. The body markers relevant for the accuracy assessment and their reference positions are presented in Table 1.

**Figure 4.** Details of the marker set placement positions.


