Fundamental Study to Evaluate Walking Skill for Visually Impaired Person

The visually impaired person recognizes the surrounding situation using a white cane and a guide dog while they walk. For the expert of them, it is very important to hear the environmental sound for recognition of their own position and surrounding situations in details. So, it means "Walking Skills" to recognize surrounding situation by using sound information. Especially, the "Walking Skills [1,2]" is necessary for movement in the place at first time. The training of the "Walking Skills" is performed at the school for visually impaired person. However, the evaluation of this is limited to subjective evaluation by leaders. Therefore, we have proposed that quantitative evaluation of the "Walking Skills" is required. And, we have tried to discuss for the quantitative evaluation of the "Walking Skills" based on human brain activity using Near Infra-Red Spectroscopy (NIRS). In this paper, we executed the quantitative evaluation of the "Walking Skills" using brain activity measurements for sighted persons without visual information during walking. We performed two kinds of experiments. In the first experiment, brain activity was measured when subjects are walking in the corridor without any visual information. As results of this experiment, the increase of cerebral blood flow of prefrontal cortex was observed when the subject moves far from the start point of these experiments. So, when the walking distance increased, it seems that the blood flow was increased because subjects felt fear as collision to the wall and so on. As another experiment, brain activity was measured when subjects walked with accompanying person as a guide helper. In this experiment, the cerebral blood flow was decreased slightly after the start a walk. From these results, it can be considered that the feeling of fear and the attention relayed to "Walking Skills" could be measured quantitatively by measuring human brain activities.