## 4 Discussion  
In this preliminary study, we have tested the performance of an integrated image processing system with an AI-based approach, suited for the estimation of the degree of motor impairment in PD patients by exploring two axial items of the MDS-UPDRS scale: gait and freezing of gait. Although we have not obtained enough data to be able to make a statistical inference, we have found, by a preliminary descriptive analysis of our data, interesting and prospective results. A subject's gait is assessed in a composite way through the combination of various observations involving different tests. Our system is able to detect and measure, in patients with PD, a reduction in stride speed and length, in the height of the feet while walking and the need for more time and more steps in turning. These different characteristics measured by the system seem to each contribute in a different way to the assignment of the subject's MDS-UPDRS score, which is assigned by a neurologist who, on the basis of their personal clinical experience, must necessarily aggregate what is observed during different tests to produce a single score represented by an integer. In particular, the deviation in the amount of time it takes a subject to turn around and change direction or to move around an obstacle seems very important. In the case of patient 03, for example, who was assigned an MDS-UPDRS score of 1, the values of their deviations in stride amplitude and speed and the height of the feet during walking were about one-third of those of patient 2, also assigned a score of 1. Despite this, while for patient 02 the deviation of the \"turning\" parameter did not reach the value of 3%, for patient 03 it exceeded 44%. Similarly, in the case of patient 04, also with an MDS-UPDRS score of 1, their even-smaller deviations compared to patient 02 for stride amplitude, speed and height of their feet during walking were compensated for by a more significant deviation of the \"turning\" parameter, which was, in their case, 94%. The system also found, in one case, a discrepancy concerning the evaluation made by the clinician: in the case of patient 01, the percentage deviations found with respect to the corresponding control subjects seemed to suggest the assignment of a higher value. The proposed system was able to discriminate different levels of gait impairment by analytically measuring the kinematics of some characteristic points of the human body. Moreover, it appeared to be able to objectively assess the freezing of gait even in the earliest stages of disease in PD patients. This preliminary work opens interesting scenarios in the objective evaluation of motor dysfunctions affecting gait in [PERSON]'s disease. Our proposed system, which includes high-definition video recording, reprocessing analysis, avatar reconstruction and  
Figure 11: Plot of distance between heels. A freezing of gait episode that occurred during the test is clearly visible and is highlighted by the red arrow. computerized measurements, ranks among the state-of-the-art tools used to obtain more quantitative, refined and graduated measurements of motor deficit. Our tool, therefore, not only seems to be correctly capable of recognizing and qualitatively highlighting the same alterations assessed by MDS-UPDRS scores (Items 3.10 and 3.11) but, by also providing a quantitative analysis of the results, can handle a wider and more finely graded range of motor disturbances. The potential applications are numerous: detecting early-stage motor deficits that would not reach a score of 1 on the qualitative assessment of the scale, identifying intermediate-grade motor deficits (e.g., more severe than a score of 1 but not so severe as to reach a score of 2), correcting for human error, increasing the degree of objectivity, ensuring greater homogeneity among evaluations of different clinicians or the same clinical neurologist at different times, and facilitating critical choice as far as an indication to advanced therapy under scrutiny, such as Deep Brain Stimulation [43,44].