Background Cognitive Reserve (CR) protects against cognitive decline, but whether CR influences the efficiency of cortical control of gait has not been reported. The current study addressed this important gap in the literature. Specifically, we determined the role of CR in moderating the efficiency of functional Near-Infrared-Spectroscopy (fNIRS)-derived HbO2 in the prefrontal cortex (PFC) assessed during active walking. We hypothesized that higher CR would be associated with more efficient brain activation patterns. Methods Participants were 55 (mean age=74.84; %female=49.1) older adults who underwent the combined walking/fNIRS protocol and had MRI data. We used an established dual-task walking paradigm that consisted of three task conditions: Single-Task-Walk (STW), Single-Task-Alpha (STA, cognitive task) and Dual-Task-Walk (DTW). Using the residuals approach, CR was derived from a word-reading test score by removing variance accounted for by socio-demographic variables, tests of current cognitive functions and a measure of structural brain integrity. Results CR moderated the change in fNIRS-derived HbO2 in the PFC across tasks. Higher CR was associated with smaller increases in fNIRS-derived HbO2 from the single tasks to dual task walking (CR x DTW compared to STW: estimate = .183; p < .001; CR x DTW compared to STA: estimate =.257; p < .001). The moderation effect of CR remained significant when adjusting for multiple covariates and concurrent moderation effects of measures of gait performance, current cognitive functions and structural integrity of the brain. Conclusion The current study provided first evidence that higher CR was associated with better neural efficiency of walking in older adults.

中文翻译：

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认知储备调节老年人步态前额叶皮层激活模式的效率

背景认知储备 (CR) 可防止认知能力下降，但尚未报道 CR 是否会影响皮质控制步态的效率。目前的研究解决了文献中的这一重要空白。具体来说，我们确定了 CR 在调节主动行走期间评估的前额叶皮层 (PFC) 中功能性近红外光谱 (fNIRS) 衍生的 HbO2 效率方面的作用。我们假设更高的 CR 将与更有效的大脑激活模式相关。方法 参与者是 55 名（平均年龄 = 74.84；女性百分比 = 49.1）的老年人，他们接受了步行/fNIRS 联合方案并获得了 MRI 数据。我们使用了一个既定的双任务步行范式，该范式由三个任务条件组成：单任务步行 (STW)、单任务阿尔法 (STA，认知任务) 和双任务步行 (DTW)。使用残差方法，CR 是通过消除由社会人口变量、当前认知功能测试和大脑结构完整性测量所引起的方差，从单词阅读测试分数中得出的。结果 CR 缓和了 PFC 中 fNIRS 衍生的 HbO2 的变化。较高的 CR 与从单任务到双任务步行的 fNIRS 衍生 HbO2 的较小增加相关（CR x DTW 与 STW 相比：估计 = .183；p < .001；CR x DTW 与 STA 相比：估计 =.257 ; p < .001)。在调整多个协变量和步态表现、当前认知功能和大脑结构完整性测量的同时调节效应时，CR 的调节效应仍然显着。