Quantitative Motor Functioning in Prodromal Parkinson Disease Lisanne J. Dommershuijsen, MSc , M. Kamran Ikram, MD, PhD, and Sirwan K. L. Darweesh, MD, PhD We read with great interest the article by Del Din et al on quantitative gait analysis to predict conversion to Parkinson disease (PD). The authors show that gait starts deteriorating 4 years before PD diagnosis and identify potential predictors of conversion to clinical PD. Although their findings add to an emerging body of literature on the role of quantitative motor assessments in prodromal PD, several key questions remain to be answered. First, during the prodromal phase of PD, subtle gait impairments may more easily become overt under challenging conditions, such as dual-task walking. Therefore, assessing the change in gait parameters under different walking conditions might reveal even earlier gait impairments in prodromal PD. In particular, this may apply to markers of postural control (eg, step width), as previous research has shown that postural control is disproportionally affected by cognitive interference in early PD. Second, the study population of Del Din et al included individuals selected for having high-risk traits for PD. The question remains to what extent their findings are generalizable to an unselected, general population. In the general population, poor gait could be more commonly driven by factors unrelated to PD, such as osteoarthritis. Moreover, gait impairments precede not only clinical PD but also many other neurological disorders. This might be problematic for the prediction of PD in a population not at high risk for PD. Alternatively, assessing quantitative gait measures specific for PD, such as shuffling, might facilitate the prediction of conversion to clinical PD in the general population. Third, motor impairments in prodromal PD are not limited to gait, as upper extremities are also commonly affected. For instance, we previously showed that impairment in manual dexterity precedes clinical PD diagnosis by 9 years. However, it remains largely unclear to what extent the predictive value for conversion to clinical PD overlaps for different quantitative motor functioning measures. If the predictive value of various impairments is largely incremental, detection of prodromal PD could be improved by assessing both upper and lower limb motor functioning. In the coming years, prospective cohort studies will address the value of gait assessments under complex walking conditions, unravel whether gait assessments can be used in the general population, and determine the incremental effect of combining motor functioning tests to predict conversion to PD. Taken together, these studies may facilitate subsequent clinical incorporation of quantitative motor assessments for the prediction of PD. Potential Conflicts of Interest Nothing to report.

中文翻译：

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前驱帕金森病的定量运动功能

前驱帕金森病中的定量运动功能 Lisanne J. Dommershuijsen，理学硕士，M. Kamran Ikram，医学博士，博士和 Sirwan KL Darweesh，医学博士，博士 我们非常感兴趣地阅读了 Del Din 等人关于定量步态分析以预测转化的文章帕金森病（PD）。作者表明，步态在 PD 诊断前 4 年开始恶化，并确定了转化为临床 PD 的潜在预测因素。尽管他们的发现增加了关于定量运动评估在前驱 PD 中的作用的新兴文献，但仍有几个关键问题有待回答。首先，在 PD 的前驱阶段，在具有挑战性的条件下，例如双任务行走，细微的步态障碍可能更容易变得明显。所以，评估不同步行条件下步态参数的变化可能会揭示前驱 PD 中更早的步态障碍。特别是，这可能适用于姿势控制的标志物（例如步宽），因为先前的研究表明姿势控制在早期 PD 中受到认知干扰的影响不成比例。其次，Del Din 等人的研究人群包括因具有 PD 高风险特征而选择的个体。问题仍然是他们的发现在多大程度上可以推广到未经选择的一般人群。在一般人群中，步态不佳可能更常由与 PD 无关的因素引起，例如骨关节炎。此外，步态障碍不仅先于临床 PD，而且先于许多其他神经系统疾病。这对于在非 PD 高风险人群中预测 PD 可能是有问题的。或者，评估特定于 PD 的定量步态测量，例如改组，可能有助于预测一般人群中转化为临床 PD。第三，前驱 PD 的运动障碍不仅限于步态，因为上肢也经常受到影响。例如，我们之前表明，手动灵活性受损比临床 PD 诊断早 9 年。然而，对于不同的定量运动功能测量，转换为临床 PD 的预测值在多大程度上重叠仍不清楚。如果各种损伤的预测值在很大程度上是递增的，则可以通过评估上肢和下肢运动功能来改善前驱 PD 的检测。在接下来的几年里，前瞻性队列研究将解决复杂步行条件下步态评估的价值，阐明步态评估是否可用于一般人群，并确定结合运动功能测试预测向 PD 转化的增量效应。综上所述，这些研究可能有助于随后将定量运动评估纳入临床以预测 PD。潜在的利益冲突 无需报告。这些研究可能有助于随后将定量运动评估纳入临床以预测 PD。潜在的利益冲突 无需报告。这些研究可能有助于随后将定量运动评估纳入临床以预测 PD。潜在的利益冲突 无需报告。