Prehypertensive Blood Pressures and Regional Cerebral Blood Flow Independently Relate to Cognitive Performance in Midlife

Abstract

BackgroundHigh blood pressure is thought to contribute to dementia in late life, but our understanding of the relationship between individual differences in blood pressure (BP) and cognitive functioning is incomplete. In this study, cognitive performance in nonhypertensive midlife adults was examined as a function of resting BP and regional cerebral blood flow (rCBF) responses during cognitive testing. We hypothesized that BP would be negatively related to cognitive performance and that cognitive performance would also be related to rCBF responses within areas related to BP control. We explored whether deficits related to systolic BP might be explained by rCBF responses to mental challenge.Methods and ResultsHealthy midlife participants (n=227) received neuropsychological testing and performed cognitive tasks in a magnetic resonance imaging scanner. A pseudocontinuous arterial spin labeling sequence assessed rCBF in brain areas related to BP in prior studies. Systolic BP was negatively related to 4 of 5 neuropsychological factors (standardized β>0.13): memory, working memory, executive function, and mental efficiency. The rCBF in 2 brain regions of interest was similarly related to memory, executive function, and working memory (standardized β>0.17); however, rCBF responses did not explain the relationship between resting systolic BP and cognitive performance.ConclusionsRelationships at midlife between prehypertensive levels of systolic BP and both cognitive and brain function were modest but suggested the possible value of midlife intervention.

Brain Regional Blood Flow and Working Memory Performance Predict Change in Blood Pressure Over 2 Years

“…A trained clinical psychologist administered the neuropsychological tests. Tests in the battery, organization into five cognitive factors, and supporting references are in Table S1 of the prior report 16 . The following factors were formed based on a principal components analysis of data prior to follow-up: (1) Memory—immediate and delayed memory for a brief story, verbal learning of unconnected items--immediate and delayed; (2) Working Memory— immediate and delayed memory for a complex figure, errors in connecting alphanumeric labelled dots, detecting retained letter-number sequences, and immediate memory of brief sequences at multiple delays; (3) Attention—sum of target items missed from two trials of vigilance task; (4) Executive Function—Stroop Color word interference and sum of all verbal fluency items; and (5) Mental Efficiency—digit vigilance times for two trials summed, digit symbol substitution test, time connecting numbered dots, and pegboard time preferred and non-preferred hand.…”

“…We hypothesized that deficits in one or more of these cognitive processes would predict the progression of BP among prehypertensive individuals. An earlier report 16 documents the neuropsychological and rCBF responsivity correlates of BP prior to follow-up among the pre-hypertensive participants and normotensive controls.…”

Vascular Aging and Cognitive Dysfunction: Silent Midlife Crisis in the Brain

“…In fact, even in prehypertensive (systolic BP >120 and <140 mm Hg or diastolic BP >80 and <90 mm Hg) middle-aged adults, an elevated systolic BP level was shown to be negatively associated with cognitive performance, including memory and executive function [8]. In a cohort study, prehypertension in midlife was also shown to be associated with increased risk of developing dementia [25].…”

“…Another study found significantly worse performance on verbal episodic memory for untreated hypertensive women; even at the prehypertensive level, the predictive performance on memory domain is less satisfactory later in life [7]. All these findings taken together indicate that reducing midlife BP, even at the prehypertensive level, may be beneficial for protecting against subsequent cognitive dysfunction and the development of dementia in later life [7,8]. Further well-founded longitudinal studies are warranted to clarify the causal relationships between arterial stiffness, BP level, and cognitive impairment before midlife by extending the study population from the elderly to the middle-aged or even young adult population.…”

“…Over a decade, many investigations have suggested that marked arterial stiffness is associated with impaired cognitive function in elderly populations [1,3,4,5,6]. Recently, for middle-aged individuals, a reciprocal interaction between high blood pressure (BP) and poor cognitive performance was suggested [7,8,9,10]. Vascular aging is acknowledged as the major pathophysiology for age-related hypertension [11]; however, the mechanisms by which vascular aging leads to cognitive dysfunction in midlife remain poorly understood.…”