Supplementary Material for: Relationship between cognitive decline and daily life gait among elderly people living in the community: A preliminary report

Introduction: Early detection and intervention are important to prevent dementia. Gait parameters have been recognized as a potentially easy screening tool for mild cognitive impairment (MCI); however, differences in gait parameters between cognitive healthy individuals (CHI) and MCI are small. Daily life gait change may be used to detect cognitive decline earlier. In the present study, we aimed to clarify the relationship between cognitive decline and daily life gait. Methods: We performed 5-cog cognitive function tests and daily life and laboratory-based gait assessments on 155 community-dwelling elderly people (75.5 ± 5.4 years old). Daily life gait was measured for 6 days using an iPod-touch with an accelerometer. Laboratory-based 10 m gait (fast pace) was measured using an electronic portable walkway. Results: The subjects consisted of 98 CHI (63.2%) and 57 cognitive decline individuals (CDI 36.8%). Daily life maximum gait velocity in the CDI group (113.7 [97.0-128.5] cm/sec) was significantly slower than that in the CHI group (121.2 [105.8-134.3] cm/sec) (p = 0.032). In the laboratory-based gait, the stride length variability in the CDI group (2.6 [1.8-4.1] was significantly higher than that in the CHI group (1.8 [1.2-2.7]) (p < 0.001). The maximum gait velocity in daily life gait was weakly but significantly correlated with stride length variability in laboratory-based gait (ρ = -0.260, p = 0.001). Conclusion: We found an association between cognitive decline and slower daily life gait velocity among community-dwelling elderly people.

引言：早期检测与干预对预防痴呆至关重要。步态参数已被认为是筛查轻度认知障碍（mild cognitive impairment, MCI）的潜在简便工具，但认知健康个体（cognitive healthy individuals, CHI）与MCI患者的步态参数差异较小。日常生活步态变化或可更早检测认知衰退。本研究旨在阐明认知衰退与日常生活步态之间的关联。
方法：本研究对155名社区居住老年人（年龄75.5±5.4岁）开展了5项认知功能测试、日常生活步态评估与实验室步态评估。采用搭载加速度传感器的iPod Touch对受试者进行为期6天的日常生活步态监测。采用便携式电子步态垫测量实验室环境下的10米快速步行步态。
结果：本研究受试者包括98名认知健康个体（63.2%）与57名认知衰退个体（cognitive decline individuals, CDI，36.8%）。认知衰退组的日常生活最大步行速度为113.7[97.0~128.5] cm/s，显著慢于认知健康组的121.2[105.8~134.3] cm/s（p=0.032）。实验室步态测试中，认知衰退组的步长变异度为2.6[1.8~4.1]，显著高于认知健康组的1.8[1.2~2.7]（p<0.001）。日常生活步态的最大步行速度与实验室步态的步长变异度呈弱但显著的负相关（ρ=-0.260，p=0.001）。
结论：本研究发现社区居住老年人的认知衰退与较慢的日常生活步行速度存在关联。