Development of a Wearable Gait Symmetry Evaluation System for Identifying Gait Symmetry by Multi-Parameters

• Main Authors: Chen, Yi-Hua, 陳怡樺
• Other Authors: Yang, Bing-Shiang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/19567261677207561730

碩士 === 國立交通大學 === 機械工程系所 === 101 === Hemiplegia is commonly caused by stroke and usually leads to an asymmetrical gait. Both before and after rehabilitation, gait assessments need to be made to determine whether the patients can do rehabilitation or how effective the rehabilitation program was. Among all gait assessments, symmetry is an important gait characteristic. Previous researchers have used inertial sensors to quantify gait symmetry, but there has been no previous study using whole waveform patterns of one stride to quantify gait symmetry in swing phase and stance phase, separately. Based on different muscle activation sequences and different implications in two phases, it is significant to quantify them separately. Therefore, we aim to develop a wearable sensor system to determine gait symmetry of thighs and shanks in these phases, separately. This easily programmable and lightweight system can be used to evaluate symmetry immediately and be used by therapists easily. An eight-camera motion capture system was used to verify the angular velocity obtained by the IMU of our developed system in sagittal plane, and we used normalized root-mean-square error to calculate the error between the two systems. Furthermore, we evaluated gait symmetry against not only thighs and shanks but also stance phase and swing phase. Three approaches were used to evaluate gait symmetry: cross-correlation, area difference and time difference. Cross-correlation and area difference are used to evaluate the waveform patterns generated by two legs over a period of time. Four pairs of angular velocity signal, which are measured from thigh in stance phase, thigh in swing phase, shank in stance phase and shank in swing phase, can be obtained in one stride of two legs. A pair of signal can be calculated to three kinds of symmetry values by IV three approaches. Eight intact healthy males (24±2 yrs, 172±6cm, 67±7kg) and two hemiparetic subjects (one male, 62yrs, 172cm, 73.5kg, Brunnstrom stage: V; one female, 47yrs, 160cm, 65.5kg, Brunnstrom stage: III) were recruited to attend the experiments. Every subject completed three trials at comfortable speed. Four strides in the middle of gaits were evaluated in each trial. The errors between motion capture and inertial sensors are 5~8%, and these values are acceptable. In clinical test, the results of the subject in Brunnstrom stage V show that the symmetry values are lower than the 95% confidence interval (CI) of intact subjects, except the values of cross-correlation. It might represent that cross-correlation is less sensitive to asymmetry gait. Besides, all the symmetry values of the hemiparetic subject in Brunnstrom stage III are less than the symmetry values of the other hemiparetic subject and the intact subjects. The values are all lower than the 95% CI of the intact subjects. This research has successfully developed a wearable sensor system to determine gait symmetry in stance phase and swing phase, separately. The system can be used easily to evaluate gait symmetry more objective and more quantitative to be provided in clinical use.