School of Medicine, Huzhou University, Huzhou Central Hospital, Huzhou, Zhejiang 313000, China.
Rory Meyers College of Nursing, New York University, New York, NY 10010, USA.
Int J Nurs Stud. 2020 Oct;110:103706. doi: 10.1016/j.ijnurstu.2020.103706. Epub 2020 Jul 12.
Exercise is known to prevent cognitive decline. Sleep quality and depression symptoms, which are associated with processing speed, are considered as common mediators in the exercise-cognition putative model. However, these mediating mechanisms have not been empirically tested in an intervention study.
The aim of this study was to evaluate the effects of a structured limbs-exercise program on general cognitive function, and to test the mediating effects and mediating pathways of depressive symptoms, sleep quality and processing speed in the relationship of exercise-induced cognitive benefits.
A two-arm and assessor-blinded randomized controlled trial.
Community-dwelling older adults with mild cognitive impairment living in an urban area in Chifeng, China.
Participants (N=116) were randomly allocated to one of the two arms: (1) a 24-week structured limbs-exercise program (3 supervised limb exercise sessions /week, 60 min /session for the first 12 weeks and 3 unsupervised practice sessions /week, 60 min /session for the following 12 weeks) or (2) health promotion classes alone. Measures of depressive symptoms, sleep quality, processing speed, and general cognitive function were collected at baseline, 12-week, and 24-week. Multivariate analysis of variance and structural equation modeling was used to test the effectiveness and mechanisms of structured limbs-exercise-induced cognitive improvement respectively.
The structured limbs-exercise program was beneficial for maintaining general cognitive function at 12 weeks (mean difference = 1.20, 95% CI [0.354, 2.054], p = 0.006) and at 24 weeks (mean difference = 1.59, 95% CI [0.722, 2.458], p = 0.001) in the intervention group. The results from the goodness-of-fit indices of structural equation modeling show as following: (1) The effect of structured limbs-exercise program on cognitive function was partially mediated by depressive symptoms, sleep quality, and processing speed, with 69.22% of joint mediation proportion; (2) Relative to the combined Z values of depressive symptoms and processing speed, sleep quality was more strongly related to cognitive function in the structured limbs-exercise program (Z= 9.294, p<0.01); (3) Processing speed was affected by depressive symptoms, sleep quality, and in turn, yielding a significant effect on cognitive function; and (4) Five potential mediating pathways for improvement in general cognitive function in the structured limbs-exercise intervention were identified.
This study shows that this exercise program can maintain general cognitive function for older adults with mild cognitive impairment. Mediating variables include depressive symptoms, sleep quality and processing speed. Future research should continue to incorporate path-oriented intervention strategies in the exercise intervention to maximize improvements in cognitive function. Registration number: ChiCTR1800016299.
运动被认为可以预防认知能力下降。睡眠质量和抑郁症状与加工速度有关，被认为是运动与认知之间的假设模型中的常见中介因素。然而，这些中介机制尚未在干预研究中得到实证检验。
本研究旨在评估结构化四肢运动方案对一般认知功能的影响，并测试抑郁症状、睡眠质量和加工速度在运动引起的认知益处关系中的中介作用和中介途径。
双臂、评估者盲法随机对照试验。
居住在中国赤峰市区的轻度认知障碍的社区老年人。
参与者（N=116）随机分配到两个组之一：（1）24 周结构化四肢运动方案（前 12 周每周 3 次监督四肢运动，每次 60 分钟，后 12 周每周 3 次非监督实践，每次 60 分钟）或（2）单独进行健康促进课程。在基线、12 周和 24 周时，评估抑郁症状、睡眠质量、加工速度和一般认知功能。采用多变量方差分析和结构方程模型分别检验结构化四肢运动引起的认知改善的效果和机制。
结构化四肢运动方案在 12 周（平均差异=1.20，95%置信区间[0.354, 2.054]，p=0.006）和 24 周（平均差异=1.59，95%置信区间[0.722, 2.458]，p=0.001）时对干预组的一般认知功能有益。结构方程模型的拟合优度指数的结果如下：（1）结构化四肢运动方案对认知功能的影响部分通过抑郁症状、睡眠质量和加工速度来介导，联合中介比例为 69.22%；（2）与抑郁症状和加工速度的综合 Z 值相比，睡眠质量在结构化四肢运动方案中与认知功能的关系更强（Z=9.294，p<0.01）；（3）加工速度受到抑郁症状和睡眠质量的影响，并反过来对认知功能产生显著影响；（4）确定了结构化四肢运动干预改善一般认知功能的五个潜在中介途径。
本研究表明，该运动方案可维持轻度认知障碍老年人的一般认知功能。中介变量包括抑郁症状、睡眠质量和加工速度。未来的研究应继续在运动干预中纳入面向路径的干预策略，以最大限度地提高认知功能的改善。注册号：ChiCTR1800016299。
