Stride Length and Foot Clearance Measurements in Parkinson Patients through IMU Wearable Sensors.

Parkinson's disease (PD) causes several symptoms including motor problems and imbalance. In more advanced stages it can present Freezing of Gait (FoG) which prevents subjects from continuing walking by blocking their legs and causing an increase in the risk of falling. In this study, the spatial gait parameters of stride length and clearance are measured using two IMUs. Data were obtained from 25 PD both before (OFF) and after (ON) dopaminergic therapy and from 18 healthy subjects (HS). PDs were divided into three groups: PD comprising all patients, NFOG comprising patients who do not present FoG, and FOG who do. The stride length and clearance values were then compared between each other both between OFF and ON and between the different groups. The study demonstrated that there is a significant difference in stride length values both between PDs and HSs and between OFF and ON in PDs. A significant difference was also found for clearance values apart from comparisons between OFF and ON states of PDs, NFOG and FOG. Furthermore, a validation of the IMU system was carried out through an accuracy analysis comparing it with an optoelectronic system. The validation reported a relative percentage error of 13.8±10.2%. The results obtained show the clear ability of the system to discriminate between PD and HS and between NFOG and FOG, paving the way for the development of rehabilitation and prevention systems for PD.