Department of Neurology, University of Pennsylvania, Philadelphia, USA.
Physiol Meas. 2010 Apr;31(4):477-95. doi: 10.1088/0967-3334/31/4/002. Epub 2010 Feb 24.
Aging is associated with an increased incidence of orthostatic hypotension, impairment of the baroreceptor reflex and lower baseline cerebral blood flow. The effect of aging on cerebrovascular autoregulation, however, remains to be fully elucidated. We used a novel optical instrument to assess microvascular cerebral hemodynamics in the frontal lobe cortex of 60 healthy subjects ranging from ages 20-78. Diffuse correlation spectroscopy (DCS) and near-infrared spectroscopy (NIRS) were used to measure relative cerebral blood flow (rCBF), total hemoglobin concentration (THC), oxyhemoglobin concentration (HbO(2)) and deoxyhemoglobin concentration (Hb). Cerebral hemodynamics were monitored for 5 min at each of the following postures: head-of-bed 30 degrees , supine, standing and supine. Supine-to-standing posture change caused significant declines in rCBF, THC and HbO(2), and an increase in Hb, across the age continuum (p < 0.01). Healthy aging did not alter postural changes in frontal cortical rCBF (p = 0.23) and was associated with a smaller magnitude of decline in HbO(2) (p < 0.05) during supine-to-standing posture change. We conclude that healthy aging does not alter postural changes in frontal cortical perfusion.
衰老是体位性低血压、压力感受器反射受损和基础脑血流量降低的发病率增加的原因。然而，衰老对脑血管自动调节的影响仍有待充分阐明。我们使用一种新型光学仪器评估了 60 名健康受试者的额叶皮层的微血管脑血流动力学，年龄范围从 20 岁到 78 岁。漫反射相关光谱（DCS）和近红外光谱（NIRS）用于测量相对脑血流量（rCBF）、总血红蛋白浓度（THC）、氧合血红蛋白浓度（HbO（2））和脱氧血红蛋白浓度（Hb）。在以下每个姿势下监测脑血流动力学 5 分钟：床头抬高 30 度、仰卧、站立和仰卧。从仰卧位到站立位的姿势变化导致 rCBF、THC 和 HbO（2）显著下降，Hb 增加，整个年龄范围（p < 0.01）。健康衰老不会改变额叶皮层 rCBF 的体位变化（p = 0.23），并且与仰卧位到站立位姿势变化期间 HbO（2）下降幅度较小相关（p < 0.05）。我们的结论是，健康衰老不会改变额叶皮层灌注的体位变化。
