Summary: Older adults with mild cognitive impairment (MCI) face higher cerebrovascular impedance, or resistance in brain blood flow, according to a new study. Researchers found this increased resistance leads to hypoperfusion, or reduced blood flow in the brain, which may contribute to cognitive difficulties in aging adults.
By using ultrasound and blood pressure tools, scientists analyzed brain blood flow in 58 older adults with MCI and 25 without, discovering a significant difference in cerebrovascular health between the two groups.
This finding suggests vascular function plays a vital role in maintaining cognitive health. The study opens new avenues for exploring interventions to improve blood flow and support cognitive function in older adults at risk of Alzheimer’s.
Key Facts
- Increased cerebrovascular impedance in MCI patients lowers brain blood flow.
- Hypoperfusion from blood flow resistance may worsen cognitive symptoms.
- The study suggests vascular health is crucial for cognitive function in aging.
Source: American Physiological Society
Older adults with mild cognitive impairment showed greater resistance to brain blood flow compared to those without cognitive impediments.
The first-of-its-kind study is published in the Journal of Applied Physiology and has been chosen as an APSselect article for October.
Brain blood flow resistance (also called cerebrovascular impedance) is linked to cognitive problems, which can manifest in several ways, including:
- Difficulty remembering recent events.
- Difficulty finding the right word or remembering a name.
- Difficulty focusing on a task.
- Disorientation in time and space.
The purpose of the study was to determine if mild cognitive impairment affects the brain’s blood vessels’ ability to transport blood.
Using blood pressure instruments and ultrasonogram imaging to measure impedance in the brain’s blood vessels, the research team studied 58 older adults with mild cognitive impairment who have a higher risk for developing Alzheimer’s disease.
The researchers compared these participants to 25 age-matched volunteers with normal cognition.
The research team found the volunteers with mild cognitive impairment had higher cerebrovascular impedance and, in turn, decreased blood flow (hypoperfusion) through the brain.
Hypoperfusion can lead to cognitive problems in older adults.
“These findings shed light on the pathophysiological mechanisms of brain hypoperfusion in older adults who have a high risk of [Alzheimer’s disease],” the researchers wrote.
“This study highlights the importance of brain vascular function in brain health in older adults,” said Rong Zhang, PhD, a professor of neurology and senior author of the study.
About this cognition and aging research news
Author: Erica Roth
Source: American Physiological Society
Contact: Erica Roth – American Physiological Society
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Patients with amnestic mild cognitive impairment have higher cerebrovascular impedance than cognitively normal older adults” by Rong Zhang et al. Journal of Applied Physiology
Abstract
Patients with amnestic mild cognitive impairment have higher cerebrovascular impedance than cognitively normal older adults
Brain hypoperfusion is associated with cognitive impairment. Higher cerebrovascular impedance modulus (Z) may contribute to brain hypoperfusion.
We tested hypotheses that patients with amnestic mild cognitive impairment (aMCI) (i.e., those who have a high risk of developing Alzheimer’s disease) have higher Z than age-matched cognitively normal individuals, and that high Z is correlated with brain hypoperfusion.
Fifty-eight patients with aMCI (67 ± 7 yr) and 25 cognitively normal subjects (CN, 65 ± 6 yr) underwent simultaneous measurements of carotid artery pressure (CAP, via applanation tonometry) and middle cerebral arterial blood velocity (CBV, via transcranial Doppler).
Z was quantified using cross-spectral and transfer function analyses between dynamic changes in CBV and CAP. Patients with aMCI exhibited higher Z than NC (1.18 ± 0.34 vs. 1.01 ± 0.35 mmHg/cm/s, P = 0.044) in the frequency range from 0.78 to 4.29 Hz.
The averaged Z in the frequency range (0.78–3.13 Hz) of high coherence (>0.9) was inversely correlated with total cerebral blood flow measured with 2-D Doppler ultrasonography normalized by the brain tissue mass (via structural MRI) across both patients with aMCI and NC (r = −0.311, P = 0.007), and in patients with aMCI alone (r = −0.306, P = 0.007).
Our findings suggest that patients with aMCI have higher cerebrovascular impedance than cognitively normal older adults and that increased cerebrovascular impedance is associated with brain hypoperfusion.
