The Irish Longitudinal Study on Ageing, University of Dublin, Trinity College, Ireland.
The Patrick G. Johnston Centre for Cancer Research, Queen's University Belfast, UK.
J Gerontol A Biol Sci Med Sci. 2022 Jun 1;77(6):1216-1221. doi: 10.1093/gerona/glab219.
Cerebral autoregulation (CAR) systems maintain blood flow to the brain across a wide range of blood pressures. Deficits in CAR have been linked to gait speed (GS) but previous studies had small sample sizes and used specialized equipment which impede clinical translation. The purpose of this work was to assess the association between GS and orthostatic cerebral oxygenation in a large, community-dwelling sample of older adults.
Data for this study came from the Irish Longitudinal Study on Ageing. A near-infrared spectroscopy (NIRS) device attached to the forehead of each participant (n = 2 708) was used to track tissue saturation index (TSI; the ratio of oxygenated to total hemoglobin) during standing. GS was assessed using a portable walkway.
Recovery was impaired in slower GS participants with a TSI value at 20 seconds (after standing) of -0.55% (95% CI: -0.67, -0.42) below baseline in the slowest GS quartile versus -0.14% (95% CI: -0.25, -0.04) in the fastest quartile. Slower GS predicted a lower TSI throughout the 3-minute monitoring period. Results were not substantially altered by adjusting for orthostatic hypotension. Adjustment for clinical and demographic covariates attenuated the association between but differences remained between GS quartiles from 20 seconds to 3 minutes after standing.
This study reported evidence for impaired recovery of orthostatic cerebral oxygenation depending on GS in community-dwelling older adults. Future work assessing NIRS as a clinical tool for monitoring the relationship between GS and cerebral regulation is warranted.
脑自动调节 (CAR) 系统可在较宽的血压范围内维持脑血流。CAR 功能障碍与步态速度 (GS) 有关，但以前的研究样本量较小，且使用了特殊设备，这阻碍了临床转化。本研究旨在评估在一个较大的、居住在社区的老年人群样本中，GS 与直立性脑氧合之间的关联。
本研究的数据来自爱尔兰老龄化纵向研究。每个参与者的额头上都附有近红外光谱 (NIRS) 设备（n = 2708），用于跟踪组织饱和度指数 (TSI；含氧血红蛋白与总血红蛋白的比值) 在站立期间的变化。GS 通过便携式步道进行评估。
恢复能力受损的 GS 较慢的参与者，在站立 20 秒时 TSI 值比最慢的 GS 四分位数低 0.55%（95%置信区间：-0.67，-0.42），而最快的四分位数则低 0.14%（95%置信区间：-0.25，-0.04）。较慢的 GS 在整个 3 分钟监测期间预测 TSI 较低。通过调整直立性低血压，结果没有发生实质性改变。调整临床和人口统计学协变量后，GS 与 TSI 之间的关联减弱，但站立后 20 秒至 3 分钟之间，GS 四分位数之间仍存在差异。
本研究报告了在居住在社区的老年人群中，GS 依赖于 GS 时，直立性脑氧合恢复受损的证据。未来评估 NIRS 作为监测 GS 和大脑调节之间关系的临床工具的工作是值得的。
