The present study implemented an objective head pose tracking technique—OpenFace 2.0 to quantify the three dimensional head movement. Children with autism spectrum disorder (ASD) and typical development (TD) were engaged in a structured conversation with an interlocutress while wearing an eye tracker. We computed the head movement stereotypy with multiscale entropy analysis. In addition, the head rotation range (RR) and the amount of rotation per minute (ARPM) were calculated to quantify the extent of head movement. Results demonstrated that the ASD group had significantly higher level of movement stereotypy, RR and ARPM in all the three directions of head movement. Further analyses revealed that the extent of head movement could be significantly explained by movement stereotypy, but not by the amount of visual fixation to the interlocutress. These results demonstrated the atypical head movement dynamics in children with ASD during live interaction. It is proposed that head movement might potentially provide novel objective biomarkers of ASD.

中文翻译：

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自闭症谱系障碍儿童面对面互动中的非典型头部运动

本研究实施了一种客观的头部姿势跟踪技术——OpenFace 2.0 来量化三维头部运动。患有自闭症谱系障碍 (ASD) 和典型发育 (TD) 的儿童戴着眼动仪与一位对话者进行结构化对话。我们用多尺度熵分析计算了头部运动刻板印象。此外，计算头部旋转范围 (RR) 和每分钟旋转量 (ARPM) 以量化头部运动的程度。结果表明，ASD 组在头部运动的所有三个方向上的运动刻板印象、RR 和 ARPM 水平均显着升高。进一步的分析表明，头部运动的程度可以通过运动刻板印象来显着解释，但不能通过对对话者的视觉固定量来解释。这些结果证明了 ASD 儿童在现场互动过程中的非典型头部运动动态。有人提出头部运动可能提供新的 ASD 客观生物标志物。