Abstract: Cognitive impairment is the most common characteristic of human aging. This characteristic is one of the main factors influencing the independent outdoor walking behaviors of the elderly, due to poor memory and sensory ability, slow thinking, slow movement, and language disorders. According to recent studies, walking is not only beneficial to the physical health of the elderly, but can also improve their memory, accelerate cognitive processing, decelerate cognitive impairment, and reduce the probability of senile dementia. However, existing studies on the walkable environment pay little attention to the elderly and it is difficult to distinguish whether the elderly's key walkable environment elements and thresholds are different from those of younger, healthy people. Therefore, this study aims to explore the walkable environment for the elderly from the perspective of cognitive impairment. The walking behaviors of elderly people with cognitive impairments living in downtown areas of Shanghai were analyzed through questionnaire survey and path description by using 13 environmental quality indexes including accessibility, convenience, safety, and comfort. Moreover, key street environmental elements that influence the daily walking path selection of the elderly with cognitive impairment were discussed by using a machine learning algorithm. The walking path selection of the elderly with cognitive impairment is mainly sensitive to environmental quality, such as functions, safety, and comfort. The importance of convenience was relatively low across four models. This might be because the elderly have more spare time and no impetus to pursue convenience and high efficiency in life-oriented walking activities. Moreover, the walking scope of the elderly with cognitive impairment is relatively small. Street environmental elements, such as interface transparency of streets, man-vehicle separation facilities, density of consumption stores, and sidewalk width have a significant influence on the path selection preferences of life-oriented walking environments. The importance of these elements are different from those of healthy people. Based on research results, some improvement suggestions were proposed from perspectives of walking accessible distance of facilities, bottom interface morphology, and quality of walking facilities along the street. The results of this study are limited to the study area and cannot comprehensively interpret influences of regional difference and environmental characteristics which are difficult to quantify. Hence, studies expanding sample size and interdisciplinary cooperation in the medical field are needed.

Key words: cognitive impairment, the elderly, life-oriented walking, street characteristics, path selection

摘要： 认知衰退是人体老化最普遍的特征，步行活动对其具有干预作用，以上海市中心城区生活街道为例，探索基于认知衰退视角的老年人宜步行环境，从可达性、便捷性、安全性、舒适性等品质维度的13个环境要素指标，借助机器学习算法推测影响认知衰退老年人日常就医、购物步行路径，选择的关键环境变量。结果显示，认知衰退老年人步行活动范围较小，沿街界面透明度、人车隔离设施、消费店面密度、人行道宽度等街道环境要素对其生活型步行环境选择偏好有较强的影响，且其适宜值与健康人群存在差异。基于研究结果，在街区设施步行可达距离、沿街底层界面形态与步行设施品质等方面提出改善建议。

关键词: 认知衰退, 老年人, 生活型步行, 街道特征, 路径选择