MacDonald Stuart W S, Hundza Sandra, Love Janet A, DeCarlo Correne A, Halliday Drew W R, Brewster Paul W H, Lukyn Timothy V, Camicioli Richard, Dixon Roger A
Department of Psychology, University of VictoriaVictoria, BC, Canada; Institute of Aging and Lifelong Health, University of VictoriaVictoria, BC, Canada.
School of Exercise Science, University of Victoria Victoria, BC, Canada.
Front Aging Neurosci. 2017 Feb 13;9:17. doi: 10.3389/fnagi.2017.00017. eCollection 2017.
: Physical function indicators, including gait velocity, stride time and step length, are linked to neural and cognitive function, morbidity and mortality. Whereas cross-sectional associations are well documented, far less is known about long-term patterns of cognitive change as related to objective indicators of mobility-related physical function. : Using data from the Victoria Longitudinal Study, a long-term investigation of biological and health aspects of aging and cognition, we examined three aspects of cognition-physical function linkages in 121 older adults. First, we examined a simple marker of physical function (3 m timed-walk) as a predictor of cross-sectional differences and up to 25-year change for four indicators of cognitive function. Second, we tested associations between two markers of gait function derived from the GAITRite system (velocity and stride-time variability) and differences and change in cognition. Finally, we evaluated how increasing cognitive load during GAITRite assessment influenced the associations between gait and cognition. : The simple timed-walk measure, commonly used in clinical and research settings, was a minor predictor of change in cognitive function. In contrast, the objectively measured indicator of walking speed significantly moderated long-term cognitive change. Under increasing cognitive load, the moderating influence of velocity on cognitive change increased, with increasing variability in stride time also emerging as a predictor of age-related cognitive decline. : These findings: (a) underscore the utility of gait as a proxy for biological vitality and for indexing long-term cognitive change; and (b) inform potential mechanisms underlying age-related linkages in physical and cognitive function.
身体功能指标，包括步速、步幅时间和步长，与神经和认知功能、发病率及死亡率相关。尽管横断面关联已有充分记录，但对于与移动相关身体功能的客观指标相关的认知变化长期模式，我们所知甚少。
利用来自维多利亚纵向研究的数据（一项关于衰老和认知的生物学及健康方面的长期调查），我们在121名老年人中研究了认知-身体功能联系的三个方面。首先，我们将身体功能的一个简单指标（3米定时步行）作为认知功能四个指标的横断面差异及长达25年变化的预测因素进行研究。其次，我们测试了源自GAITRite系统的两个步态功能指标（速度和步幅时间变异性）与认知差异及变化之间的关联。最后，我们评估了在GAITRite评估期间增加认知负荷如何影响步态与认知之间的关联。
临床和研究环境中常用的简单定时步行测量，是认知功能变化的一个次要预测因素。相比之下，客观测量的步行速度指标显著调节了长期认知变化。在认知负荷增加的情况下，速度对认知变化的调节作用增强，步幅时间变异性增加也成为与年龄相关认知衰退的一个预测因素。
（a）强调了步态作为生物活力的替代指标及长期认知变化指标的作用；（b）为身体和认知功能中与年龄相关联系的潜在机制提供了信息。
