Background

Quantitative assessments of activities of daily living (ADL) play an essential role in evaluating the impact of disease and interventions on people's quality of life. Motion capture systems traditionally used for quantitative assessments of postural transitions and movement associated with ADL are limited to the laboratory setting. Wearable accelerometers can remove these limitations and enable easier-to-use, longer-term, and remote functional evaluations.

Objective

To investigate the validity of a single tri-axial accelerometer mounted on the head for monitoring postural transition and the timed-up-and-go test.

Methods

Two accelerometers with a sampling frequency of 100 Hz were attached to twelve able-bodied study participants' sternum and right mastoid process. We developed algorithms for the functional calibration of accelerometers and the detection of the postural transitions by measuring the head inclination angle and variations of the gravitational components of the accelerometer readout. Participants performed a battery of ADL tests involving a wide variety of postural transitions. The head-mounted accelerometers results were compared with a sternum-mounted accelerometer and validated against a video motion capture system as a gold standard reference.

Results and Significance

The results indicate that, utilizing our proposed algorithm, a single tri-axial accelerometer mounted on the head can deliver high accuracy (>95 %), sensitivity (>90 %), and specificity (100 %) for detecting both postural transitions and walking events. Together with the small size and unobtrusive placement of the head-mounted accelerometer, these results demonstrate an attractive solution for the reliable assessment of ADLs and clinical evaluations based on functional tests such as the timed-up-and-go test.

中文翻译：

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研究安装在头部的单个三轴加速度计的有效性，用于监测日常生活活动和计时测试

背景

日常生活活动 (ADL) 的定量评估在评估疾病和干预措施对人们生活质量的影响方面发挥着重要作用。传统上用于定量评估与 ADL 相关的姿势转换和运动的动作捕捉系统仅限于实验室环境。可穿戴加速度计可以消除这些限制，并实现更易于使用、更长期和远程的功能评估。

客观的

研究安装在头部的单个三轴加速度计的有效性，用于监测姿势转换和计时起跑测试。

方法

两个采样频率为 100 Hz 的加速度计连接到 12 名身体健全的研究参与者的胸骨和右侧乳突。我们通过测量头部倾斜角和加速度计读数的重力分量变化，开发了用于加速度计功能校准和姿势转变检测的算法。参与者进行了一系列 ADL 测试，涉及各种姿势转换。将头戴式加速度计结果与胸骨安装式加速度计进行比较，并针对作为黄金标准参考的视频运动捕捉系统进行验证。

结果和意义

结果表明，利用我们提出的算法，安装在头部的单个三轴加速度计可以提供高精度 (>95%)、灵敏度 (>90%) 和特异性 (100%)，用于检测姿势转换和步行事件。再加上头戴式加速度计的小尺寸和不显眼的放置，这些结果证明了一个有吸引力的解决方案，用于基于功能测试（如定时启动测试）对 ADL 进行可靠评估和临床评估。