Summary: USC researchers used MRI to identify blood vessel dysfunction in the brain’s temporal lobes as a potential early biomarker for mild cognitive impairment and dementia, highlighting microvascular abnormalities that occur regardless of Alzheimer’s-related changes.

Key Takeaways

  • MRI as a Diagnostic Tool: USC researchers used MRI to identify microvascular abnormalities in the brain’s temporal lobes, revealing blood vessel dysfunction as a potential early biomarker for dementia, independent of Alzheimer’s-related changes.
  • Vascular Dysfunction and Memory Impairment: Blood vessels in the temporal lobes showed impaired dilation in individuals with mild cognitive impairment (MCI), emphasizing the role of vascular health in early memory decline.
  • Therapeutic Implications: The findings suggest that focusing on vascular health and incorporating MRI-based diagnostics could improve early detection and treatment of dementia, with potential benefits from certain blood pressure medications to protect vascular function.

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Researchers at the University of Southern California (USC) have identified a connection between mild cognitive impairment (MCI) and blood vessel dysfunction in the brain’s temporal lobes, which play a vital role in memory. Using MRI, the team uncovered microvascular abnormalities that could serve as early biomarkers for dementia and guide future therapeutic strategies.

Key Findings

The study, published in Neurology, found that blood vessel dysfunction in the temporal lobes occurred in individuals with MCI, regardless of the presence of amyloid buildup, a hallmark of Alzheimer’s disease.

“We’re studying the ability of these very small vessels to respond to stimuli and to dilate, and they’re showing dysfunction in people who have memory problems,” says senior author Daniel Nation, PhD, a professor of gerontology and medicine at the USC Leonard Davis School of Gerontology. “It could implicate blood vessel dysfunction in a very early stage of memory loss. It happened whether or not people had Alzheimer’s-related brain changes. They still had this blood vessel problem if they had memory issues.”

Study Design

The research involved 144 independently living older adults who underwent neuropsychological assessments, blood tests, and brain MRI. During the MRI scans, participants held their breath for 15-second intervals to trigger blood vessel dilation—a process called cerebrovascular reactivity, which helps regulate oxygen levels in the brain.

Researchers focused on blood vessels in the temporal lobes. Participants whose vessels failed to dilate properly showed signs of cognitive impairment.

“With this approach, we can pinpoint the problem to the blood vessels and their ability to dilate. That’s not the way people usually think about memory impairment in older adults,” Nation says. “There’s an increasing realization that the main cause of dementia is not actually Alzheimer’s disease, it’s mixed pathology. If you just focus on amyloid, you’re certainly not going to get the full picture. Maybe this technique should be incorporated into our diagnostic approaches.”

Focus on Vascular Health

“Our findings underscore the need to focus on vascular health as a critical factor in memory decline,” says first author Arunima Kapoor, a graduate student at the University of California, Irvine.

Nation also notes that certain blood pressure medications may help protect vascular function and preserve memory, though additional research is required.