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Gait characteristics vary among people and correspond to individual differences of external and internal traits. Recent studies on autism spectrum disorders (ASD) reported that gait characteristics are associated with a walker s autistic trait. Previous studies measured gait characteristics with walking alone and did not investigate gait characteristics in interactive situations. The goal of this study was to examine the correlation between ASD traits and gait characteristics in typically developed (TD) young adults. The subjects completed a Subthreshold Autism Trait Questionnaire (SATQ) for quantitative measurement of autistic traits. After completing the questionnaire, the subjects participated in walking experiments in pairs using an inertial measurement unit (IMU)-type three-dimensional motion capture system. Two participants walked toward each other and had to avoid collision with their counterparts. The norm in the X-and Y-axis directions of acceleration, and the norm in the X-, Y-, and Z-axis directions of the angular velocity of four body parts (waist, left/right foot, and head) were calculated. In this study, the standard deviation of each norm and the average pitch were used as evaluation indices of the magnitude of sway of the body. Each parameter was calculated in two areas: the Walking Area (from the 3rd to 6th steps) and the Passing Area (from the 7th to 10th steps). Multiple regression analysis was performed to determine the factors that explain the SATQ scores. All explanatory variables were standardized, and a multiple linear regression analysis was performed. The results revealed that when the distance between the two subjects at the time of passing each other was 20 cm, there was a strong correlation between the SATQ score and the standard deviation of the norm of the angular velocity of the waist from the 7th to 10th steps. This nding suggests that compared with TD individuals, individuals with severe ASD traits signi cantly increase the standard deviation of the norm of the angular velocity of the waist in order to avoid contact with their counterparts.

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要旨： 4 7 4 1 2 キーワード： 3 澤留 朗 2014 多田充徳 竹村 裕 河内まき子 持丸正明 ー 50 ー Abstract : Entire gait characteristics were quantized by principal component analysis (PCA) for eight children (longitudinal survey from the age of 4 years to 7) to reveal the age-related difference in children. Temporal sequence of lower-limb angle and joint moment were compressed into lower dimensional space by PCA those were then evaluated in terms of change in gait pattern and variability among different age group. As a result of PCA, both first and second principal component (PC1 and PC2) were revealed to represent the role ofankle joint. This change was reported as typical difference between children and adults in the previous research. We found out that the gait pattern continued to change linearly in the lower dimensional space, while its variability were converged into constant value with age.These results suggest that development of gait pattern and acquiring its repeatability were independent phenomena. Also, it is clear that PCA enabled us to evaluate change in entire gait pattern keeping as much information as possible that can not be achieved by kinematic index such as step length or cadence.

: Falls are the leading cause of unintentional injuries in children and more than half of all non-fatal injuries result from falls. In this paper, we utilize inclination angle to evaluate gait, a method previously applied to motion analysis in older people. Our goal was to reveal differences in children of different age. We conducted longitudinal measurements for 4 years, starting at the age of 4, to obtain gait data of normally developing children including four boys and four girls. Center of mass of the body and center of pressure were calculated using motion analysis software (C-Motion) and the inclination angle was computed in the anteroposterior and mediolateral direction.The peak value in the mediolateral direction decreased significantly with age. On the other hand, the peak value in the anteroposterior direction did not change significantly. The tendency to change was not consistent in the anteroposterior direction. These results suggest that sway in the anterior direction represents not only unstable posture but also has a role in generating step length in gait and medial sway does represent unstable posture. Therefore, sway in the mediolateral direction is a more meaningful index than that in the anteroposterior direction.