Advanced Analysis of Optoelectronic System Signals to Assess Postural Behavior in Parkinson’s Disease

Postural instability is one of the main motor symptoms in Parkinson's disease, affecting significantly balance and increasing the risk of falls. To evaluate this symptom, the Pull Test can be employed as a clinical assessment tool. However, the outcome of the test is strictly related to the examiners' subjective interpretations. Since this aspect could compromise the accuracy and consistency of performed trials, measurement tools can be utilized to perform an objective evaluation based on quantitative data. This study deals with the processing of Pull Test signals recorded from an optoelectronic system to estimate temporal indexes such as the Weight Shift Time, the Recovery Time and the Total Time. The analysis performed on a dataset of 28 Parkinson's affected patients and 8 healthy controls, included as a reference, demonstrated a correlation with the number of steps, the MDS-UPDRS score and the stability of the trials. In particular, the reported WST index values are 0.97±0.45 s for score 0 trials, 1.42±0.34 s for score 1 trials, 2.12±0.39 s for score 2 trials and 3.55±0.11 s for score 3 trials, which highlights the possibility of using this index as an instrumental and objective assessment of the Pull Test outcome.