Fractality as a quantitative assessment tool for tic disorders and functional tic-like behaviors

项目摘要 抽搐的自然史的特点是男孩的患病率高，发病年龄约为4 - 6岁， 年龄最初的抽搐症状通常是影响面部、头部和颈部的简单运动抽搐。第一次发声抽搐 平均几年后发生，通常是一个简单的声音抽搐，如清喉咙或嗅。如果 抽搐持续一年以上，严重程度通常在8至12岁左右达到高峰。大多数人 抽搐在成年早期之前得到显著改善或完全消退。最近，虽然抽搐在 近年来，Tourette综合征（TS）患者的发病率迅速增加，但也观察到了不同的模式。 一些青少年和年轻人经历过突然发作的复杂的抽搐样运动， 发声这些患者在其他几个特征上也有显著差异， 行为现在被称为功能性神经症状障碍与抽搐，或功能性抽搐样行为 （FTLB）。然而，将FTLB与典型抽搐区分开来仍然具有挑战性，并且诊断和治疗是非常困难的。 在世界各地的许多中心正在积极研究的重要问题。 抽动障碍与其他运动障碍的区别不仅在于个体的现象学， 抽搐，但也通过抽搐的时间：他们既不是有节奏的，也不是完全不可预测的。相反，抽搐倾向于 发生在集群（几秒钟内的几个抽搐发作，随后是一段长时间的无抽搐时间）。对 在较长的时间尺度上，几次抽搐发作之后可能是一个相对无抽搐的时期，反复发作 在几分钟内分组，患者通常在几天或几周内描述类似的模式。基于这种自我- 在不同时间尺度上的相似性，TS中抽搐的分形时间在20多年前就被证明了，我们 最近将这些结果扩展到临时抽动障碍和TS，应用物理模型， 在相对简短的数据集（5分钟）中测量分形维数（Df）。tic时间序列的Df与 提示Df可作为反映抽动严重程度的客观指标。 我们假设抽搐的分形维数Df可以区分FTLB和典型抽搐。具体而言，FTLB 可能不显示分形图案，或者定量测量的分形维数可能与典型的分形维数不同。 抽搐本提案的目的是研究Df，具体目标如下： 抽搐或FTLB的视频样本，对诊断不知情，由当地和全球合作者提供，以及 来检验这个假设。长期目标是找到一个客观的衡量标准，区分FLTB 如果Df能够成功地证明两者之间的差异，未来的研究可以 看看合并症，治疗，以及当健康个体模仿抽搐时它们如何变化。

Project summary The natural history of tics is characterized by a high prevalence in boys, with onset around around 4‒6 years of age. The initial tic symptoms are usually simple motor tics affecting the face, head, and neck. The first vocal tic occurs on average a few years later, and is usually a simple vocal tic such as throat clearing or sniffing. If the tics persist more than a year, the severity usually peaks around the age of 8 to 12 years. Most individuals with tics undergo significant improvement or complete resolution before early adulthood. Recently, while tics in patients with Tourette syndrome (TS) have been increasing rapidly, a different pattern has also been observed. Some teenagers and young adults have experienced sudden onset of complex tic-like movements and vocalizations. These patients differ significantly on several other features as well, and such distinct tic-like behavior is now referred to as functional neurological symptom disorder with tics, or functional tic-like behavior (FTLB). However, differentiating FTLB from typical tics is still challenging, and diagnosis and treatment are important issues under active study in numerous centers worldwide. Tic disorders are distinguished from other movement disorders not only by the phenomenology of individual tics, but also by the timing of tics: they are neither rhythmic nor completely unpredictable. Rather, tics tend to occur in clusters (several tic attacks within a few seconds, followed by an extended period of tic-free time). On longer time scales, several bouts of tics may be followed by a relatively tic-free period with repeated episodes grouped over minutes, and patients often describe a similar pattern over days or weeks. Based on this self- similarity over different time scales, fractal timing of tics in TS was demonstrated over 20 years ago, and we recently extended those results to both Provisional Tic Disorder and TS, applying a model from physics to measure fractal dimension (Df) in relatively brief data sets (5 minutes). The Df of the tic time series correlates with the tic severity, suggesting that Df may be useful as an objective indicator of tic severity. We hypothesized that the fractal dimension Df of tics may distinguish FTLB from typical tics. Specifically, FTLB may not show a fractal pattern, or the quantitatively measured fractal dimension may differ from that of typical tics. The objective of this proposal is to investigate Df with the following specific aim: Df will be computed from video samples of tics or FTLB, blind to diagnosis, contributed locally and from collaborators worldwide, and compared to test this hypothesis. The long-term goal is to find an objective measure that distinguishes FLTB from tic disorders, and if Df can be successfully demonstrated to differ between the two, future studies could look at comorbidities, treatment, and how they change when healthy individuals mimic tics.