2011 srp powerpoint

The Relationship Between Ambulatory Blood Pressure and

Cognitive Performance

Jennifer Dalecki2010-2011

AbstractAlthough some research has linked cardiovascular risk factors to declines in

cognitive function; other studies have not demonstrated a relationship. One explanation for discrepant findings are differences in the methods used to measure blood pressure (BP). Most studies acquired a measure of clinical blood pressure (BP), meaning a BP taken in a professional setting by a doctor or clinician. Clinical BP, can vary because of the white-coat effect and various other factors, is often an unreliable indicator of an individual’s actual blood pressure. In contrast, 24-hour ambulatory blood press (ABP) has been shown to be more reliable in studies linking BP to brain changes believed to be caused by hypertension such as white matter abnormalities. The purpose of this study was to examine the relationship between 24-hour ABP and decline in cognitive performance in adults over the age of 75. It is hypothesized that those with higher ABP readings will show more evidence of cognitive decline, whereas those with lower ABP will see less evidence of cognitive deterioration. Using participants 75 years or older from a four year longitudinal study, ABP measures were related to results from cognitive performance testing. Results were analyzed by dividing the participant pool into high, middle, and low BP levels and assessing the decline in cognitive performance over the span of four years. Analysis showed no significant correlation between 24-hour blood pressure and memory and speed of processing measures.

Introduction

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance

• White matter=made up of axons; allow nerves to communicate; enables brain to operate effectively

• WMH associated with increasing age (particularly in frontal and temporal regions)

• WMH= “brain rust”; indicates injury to axons

• WMH linked to hypertension and vascular risk factors (heart attack, stroke, heart disease, etc.)

• WMH linked to decline cognitive performance, especially speed of processing (Wakefield)

• Cannot imply complete transitivity– WMH correlates with vascular risk factors and

cognitive decline ≠ vascular risk factors cause cognitive decline

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance

(Intro cont.)

Clinical BP vs. Ambulatory BP• Research linking vascular factors with cognitive decline

inconclusive• Studies used clinical BP (taken in professional setting);

often poorly reproducible and not rep. of average BP• Ambulatory BP (measures at regular intervals for 24

hours)

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance

ABP Superiority• Compared BP reproducibility of patients over 80• Concluded more consistency in ABP over two years

The Relationship Between Ambulatory Blood Pressure and Cognitive Function

Problem Statement & HypothesesHow do ambulatory blood pressure readings relate to an individual’s capacity for cognitive function ?

Hypotheses:Higher systolic ambulatory blood pressure readings will be associated with more severe decline in cognitive function Lower ambulatory blood pressure readings will be associated with more regular cognitive function

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance

Variables

The Relationship of Ambulatory Blood Pressure and Cognitive Performance

Independent Variable: Systolic ambulatory blood pressureDependent Variable: Decline in performance evaluations of cognitive functions(memory, speed of information processing)Control: None

Methodology

The Relationship of Ambulatory Blood Pressure and Cognitive Performance

Using participants in late 70s and older:• Ambulatory Blood Pressure• Trail Making Test A & B• Stroop Color and Words Test • Wechsler Adult Reading Test (WTAR)

Example of Trail Making Test

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance

Stroop Color and Words Test

The Relationship of Ambulatory Blood Pressure and Cognitive Performance

Data Interpretation

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance

• Split group into three groups (low, middle, high BP)• Compare ABP with cognitive function across

domains

P-Value: .88276

>.05 = NO STATISTICAL SIGNIFICANCE

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Trails Test vs. Systolic Ambulatory Blood Pressure

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Stroop Color and Words Test vs. Systolic Ambulatory Blood Pressure

P-Value: .420308

>.05 = NO STATISTICAL SIGNIFICANCE

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Ambulatory Blood Pressure

WTAR Scores vs. Systolic Ambulatory Blood Pressure

P-Value: .161183

>.05 = NO STATISTICAL SIGNIFICANCE

Conclusions

• No statistically significant figures• Suggests minimal relationship between

ambulatory blood pressure and cognitive performance

• Disagrees with hypothesis

Error Analysis/ Future Work

• Volunteer bias• Arbitrary division of subject pool• Data from first year of longitudinal study

• RBANS/ CALCAP• More subjects; more diversity• More specific division of pool

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(2006). Regional white matter and neuropsychological functioning across the adult lifespan. Biological Psychiatry,60, 444–453.

• Kaplan RF, Cohen RA, Moscufo N et al. Demographic and biological influences on cognitive reserve. J Clin Exp Neuropsychol Mar 2009;31:1–9.

• Lashley, K. S. (1931). Mass action in cerebral function.Science, 73, 245–254.• Sakakibara R, Hattori T, Uchiyama T et al. Urinary function in elderly people with and without

leukoaraiosis: Relation to cognitive and gait function. J Neurol Neurosurg Psychiatry 1999;67:658–660.

• Welsh-Bohmer, K. A., & Madden, D. J. (2002). Benign senescent forgetfulness, age-associated memory impairment, and age-related cognitive decline. In J. R. M. Copeland, M. T. Abou-Saleh, & D. G. Blazer (Eds.), Principles and practice of geriatric psychiatry(2nd ed., pp. 303–304). John Wiley & Sons.

The Relationship Between Ambulatory Blood Pressure and Cognitive Performance