The Pulsatile Brain, Pulse Pressure, Cognition, and Antihypertensive Treatments in Older Adults: A Functional NIRS Study

Abstract

Abstract Age-related arterial stiffness increases pulsatility that reaches the cerebral microcirculation, compromises cerebrovascular health and lead to cognitive decline. The presence of cardiovascular risk factors (CVRFs) such as high blood pressure can exacerbate this effect. Despite extensive research on the impact of antihypertensive treatments on reducing arterial stiffness, little is known about the impact of antihypertensive treatments on pulsatility in cerebral microcirculation. This study investigated the impact of antihypertensive treatments on cerebral pulsatility and cognition in older adults with CVRFs. Participants were 42 older adults with diverse CVRFs in two groups of untreated (\(n=\) 21, mean 67.2 \(\pm\) 5.9 years old, 57.1\(\text{\%}\) female) and treated with antihypertensive medications (\(n=\) 21, mean 67.2 \(\pm\) 5.5 years old, 61.1\(\text{\%}\) female). Cognitive scores of processing speed and executive functions were evaluated behaviorally using the four subsets of the Stroop test. A near-infrared spectroscopy (NIRS) device recorded hemodynamics data from the frontal and motor cortex subregions. The data were then used to extract an optical index of cerebral pulsatility. Results indicated that after controlling for CVRFs, the antihypertensive treatment is associated with lower cerebral pulsatility (untreated 33.99 \(\pm\) 6.68 vs. treated 28.88 \(\pm\) 5.39 beats/min, \(p\) \(=\) 0.009). In both groups cerebral pulsatility was associated with pulse pressure (\(p\) \(<\)0.05). Also, treated group had significantly higher cognitive scores in executive functions compared with the untreated group (\(p\) \(<\)0.05). These results suggest that beyond its known effect on blood pressure, antihypertensive treatments might also favor cerebrovascular health by reducing pulsatility in the cerebral microcirculation.