Digital evaluation of bradykinesia of upper limbs in patients with Parkinson's disease

Abstract

Objective The 3D motion capture system was used to measure the upper limb bradykinesia in Parkinson's disease (PD) to make up for the lack of artificial measurement. Methods Ninteen patients with PD (PD group) and 10 healthy subjects (control group) were recruited from June to December 2019 in Tianjin Huanhu Hospital. All the subjects completed the Unified Parkinson's Disease Rating ScaleⅢ (UPDRS⁃Ⅲ) evaluation in the room equipped with 3D motion capture system. The thumb and index finger of the subjects were fixed with reflective markers to collect motion information. In this study, only the action of finger tapping was evaluated digitally, and five parameters were extracted from the evaluation results: 1) average maximum amplitude of finger taps (amp). 2) Average finger tapping interval (intval). 3) Average zero⁃crossing occurrences of acceleration (zc). 4) Average of the forward maximum velocity (v1). 5) Average of the negative maximum velocity (v2). Using receiver operating characteristic curve (ROC) to evaluate the value of intval, zc and their combination indexes in the diagnosis of upper limb bradykinesia in PD. Results In PD group, UPDRS⁃Ⅲ score was 33.79±13.14, bradykinesia score was 13.61±5.26, upper limb bradykinesia score was 6.61±2.65, finger tapping score was 1.68±0.78. Intval (P=0.001) and zc (P=0.004) in PD group were higher than those in control group, and the difference was statistically significant. The ROC curves of intval and zc for upper limb bradykinesia showed that the AUC of them were 0.858 (95%CI: 0.743-0.973, P=0.000) and 0.799 (95%CI: 0.642-0.955, P=0.008); the sensitivity was 0.737, 0.921, and the specificity was 0.900 and 0.600, respectively. After the combination ofintvaland zc,the AUC was 0.858(95%CI:0.752-0.964, P=0.001),the sensitivity and specificity were 0.711and0.100,respectively. Conclusions The digital evaluation of upper limb bradykinesia in PD can be realized by using 3D motion capture system, which makes up for the deficiency of manual evaluation to a certain extent. The extracted parameters intval and zc have high sensitivity and specificity, which are expected to be used as characteristic indicators for early screening of PD.

DOI：10.3969/j.issn.1672⁃6731.2020.08.012