Analysis of angular velocity during toe tapping for the quantification of the lower limb bradykinesia in patients with idiopathic Parkinson's disease

The purpose of this study was to analyze bradykinesia of toe tapping movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. 39 PD patients (age: 65.5 ± 11.2 yrs, H&Y stage:2.3 ± 0.5), 14 eldelry subjects with comparable mean age (65.0±3.9 yrs) and 17 healthy young subjects (24.1±2.1 yrs) participated in this study. Angular velocity during repetitive toe tapping movement was measured in both feet using a gyro sensor system. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity signal. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.02). All measures were significantly correlated with UPDRS scores(r=-0.689^∼-0.825). These results suggest that the developed system can be used as quantitative measures of the lower limb bradykinesia in PD patients.