Institute for Neural Computation, University of California, San Diego, La Jolla, CA, USA.
Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX, USA.
J Neurol Sci. 2022 Mar 15;434:120154. doi: 10.1016/j.jns.2022.120154. Epub 2022 Jan 22.
Head tremor (HT) is a common feature of cervical dystonia (CD), usually quantified by subjective observation. Technological developments offer alternatives for measuring HT severity that are objective and amenable to automation.
Our objectives were to develop CMOR (Computational Motor Objective Rater; a computer vision-based software system) to quantify oscillatory and directional aspects of HT from video recordings during a clinical examination and to test its convergent validity with clinical rating scales.
For 93 participants with isolated CD and HT enrolled by the Dystonia Coalition, we analyzed video recordings from an examination segment in which participants were instructed to let their head drift to its most comfortable dystonic position. We evaluated peak power, frequency, and directional dominance, and used Spearman's correlation to measure the agreement between CMOR and clinical ratings.
Power averaged 0.90 (SD 1.80) deg/Hz, and peak frequency 1.95 (SD 0.94) Hz. The dominant HT axis was pitch (antero/retrocollis) for 50%, roll (laterocollis) for 6%, and yaw (torticollis) for 44% of participants. One-sided t-tests showed substantial contributions from the secondary (t = 18.17, p < 0.0001) and tertiary (t = 12.89, p < 0.0001) HT axes. CMOR's HT severity measure positively correlated with the HT item on the Toronto Western Spasmodic Torticollis Rating Scale-2 (Spearman's rho = 0.54, p < 0.001).
We demonstrate a new objective method to measure HT severity that requires only conventional video recordings, quantifies the complexities of HT in CD, and exhibits convergent validity with clinical severity ratings.
头部震颤（HT）是颈性肌张力障碍（CD）的常见特征，通常通过主观观察来量化。技术的发展为测量 HT 的严重程度提供了替代方法，这些方法客观且易于自动化。
我们的目标是开发 CMOR（基于计算机视觉的软件系统），以从临床检查期间的视频记录中量化 HT 的振荡和方向方面，并测试其与临床评分量表的收敛效度。
对于由肌张力障碍联盟招募的 93 名孤立性 CD 和 HT 参与者，我们分析了参与者被指示让头部漂移到最舒适的扭曲位置的检查片段的视频记录。我们评估了峰值功率、频率和方向优势，并使用 Spearman 相关系数来衡量 CMOR 与临床评分之间的一致性。
功率平均值为 0.90（SD 1.80）deg/Hz，峰值频率为 1.95（SD 0.94）Hz。主导的 HT 轴为 50%的俯仰（前/后斜颈）、6%的滚动（侧斜颈）和 44%的偏航（斜颈）。单侧 t 检验显示次要（t=18.17，p<0.0001）和第三（t=12.89，p<0.0001）HT 轴有实质性贡献。CMOR 的 HT 严重程度测量值与多伦多西部痉挛性斜颈评定量表-2 的 HT 项目呈正相关（Spearman 的 rho=0.54，p<0.001）。
我们展示了一种新的客观方法来测量 HT 的严重程度，该方法仅需要常规视频记录，量化了 CD 中 HT 的复杂性，并与临床严重程度评分具有收敛效度。
