Abstract
Walking and reading are two major difficulties in daily life for persons with visual impairments. Their walking instability has been recognized by orientation and mobility specialists, but it is difficult to quantitatively evaluate walking instability as compared with shorter steps. Easy and quantitative evaluation of walking instability in persons with visual impairments is essential to introduce and evaluate effective mobility training. In the present study, whole-body walking instability in the absence of visual information was quantified using a point-light walker (PLW) reconstructed from major joint movements detected by an infrared sensor system (KINECT for Windows). Seven persons (46 ± 14 years old) with normal vision served as walkers in two different conditions—eyes opened and eyes closed. The frontal animation sequences of the PLW were shown by 17 white dots corresponding to the locations of the head and major joints, which were scaled to the same height. Within a step cycle, we measured horizontal and vertical deviations of all point-lights from their mean trajectories. The eyes-closed condition made walking unstable with greater horizontal fluctuations in the frontal view, especially in both hips (right: 4.4 ± 1.8→ 5.4 ± 1.6cm, p < 0.05; left: 4.3 ± 1.5→ 5.4 ± 1.5 cm, p < 0.05) and the center of gravity (4.2 ± 1.8→ 5.2 ± 1.6 cm, p < 0.05). Additionally, vertical movements of the right knee (6.0 ± 2.0→ 4.5 ± 2.3 cm, p < 0.05) and right hip (4.1 ± 2.0→ 3.3 ± 1.7 cm, p < 0.05) were reduced in the eyes-closed condition. Thus, walking instability in the absence of visual information was quantitatively characterized by an increased lateral sway of hips and the center of gravity. Infrared sensor-aided PLWs could provide an useful tool to gain insight into walking stability control in persons with visual impairments.
Meeting abstract presented at VSS 2016