Emergent tremor in Parkinson’s disease (PD) can occur during sustained postures or movements that are different from action tremor. Tremor can contaminate the clinical rating of bradykinesia during finger tapping. Currently, there is no reliable way of isolating emergent tremor and measuring the cardinal motor symptoms based on voluntary movements only. In this study, we investigated whether emergent tremor during repetitive alternating finger tapping (RAFT) on a quantitative digitography (QDG) device could be reliably identified and distinguished from voluntary tapping. Ninety-six individuals with PD and forty-two healthy controls performed a thirty-second QDG-RAFT task and the Movement Disorders Society – Unified Parkinson’s Disease Rating Scale Part III (MDS-UPDRS III). Visual identification of tremor during QDG-RAFT was labeled by an experienced movement disorders specialist. Two methods of identifying tremor were investigated: 1) physiologically informed temporal thresholds 2) XGBoost model using temporal and amplitude features of tapping. The XGBoost model showed high accuracy for identifying tremor (area under the precision-recall curve of 0.981) and outperformed temporal-based thresholds. Percent time duration of classifier-identified tremor showed significant correlations with MDS-UPDRS III tremor subscores (r = 0.50, p < 0.0001). There was a significant change in QDG metrics for bradykinesia, rigidity, and arrhythmicity after tremor strikes were excluded (p < 0.01). The results demonstrate that emergent tremor during QDG-RAFT has a unique digital signature and the duration of tremor correlated with the MDS-UPDRS III tremor items. When involuntary tremor strikes were excluded, the QDG metrics of bradykinesia and rigidity were significantly worse, demonstrating the importance of distinguishing tremor from voluntary movement when rating bradykinesia.

帕金森病 （PD） 中的紧急震颤可能发生在不同于动作性震颤的持续姿势或运动期间。震颤会污染手指敲击时运动迟缓的临床评级。目前，没有可靠的方法可以隔离紧急震颤并仅根据自主运动来测量主要运动症状。在这项研究中，我们调查了是否可以可靠地识别定量数字化成像 （QDG） 设备上重复交替手指敲击 （RAFT） 期间的紧急震颤并将其与自主敲击区分开来。96 名 PD 患者和 42 名健康对照者执行了第 32 次 QDG-RAFT 任务和运动障碍协会 – 统一帕金森病评定量表 III 部分 （MDS-UPDRS III）。QDG-RAFT 期间震颤的目视识别由经验丰富的运动障碍专家标记。研究了两种识别震颤的方法： 1） 生理知情的时间阈值 2） 使用敲击的时间和振幅特征的 XGBoost 模型。XGBoost 模型在识别震颤（精度-召回曲线下面积为 0.981）方面表现出很高的准确性，并且优于基于时间的阈值。分类器识别的震颤的持续时间百分比与 MDS-UPDRS III 震颤子评分呈显着相关性 （r = 0.50，p < 0.0001）。排除震颤后运动迟缓、僵硬和心律失常的 QDG 指标发生显着变化 （p < 0.01）。结果表明，QDG-RAFT 期间的紧急震颤具有独特的数字签名，震颤持续时间与 MDS-UPDRS III 震颤项目相关。 当排除不自主震颤时，运动迟缓和僵硬的 QDG 指标明显变差，这表明在评估运动迟缓时区分震颤和自主运动的重要性。