Alzheimer’s may begin with a silent drop in brain blood flow
Science Daily
February 24, 2026
AI-Generated Deep Dive Summary
A new study from the Mark and Mary Stevens Neuroimaging and Informatics Institute at USC suggests that subtle changes in brain blood flow and oxygen use may be early indicators of Alzheimer’s disease. Researchers found that older adults with cognitive impairment showed links between reduced cerebrovascular function and hallmark signs of Alzheimer’s, such as amyloid plaque buildup and hippocampus shrinkage. By using non-invasive techniques like transcranial Doppler ultrasound and near infrared spectroscopy, the study measured blood flow velocity in major arteries and oxygen delivery to brain tissue. These methods could potentially offer a simpler, less costly alternative to traditional MRI and PET scans for early detection.
The findings reveal that individuals with better vascular health—similar to patterns seen in cognitively healthy adults—tended to have lower amyloid levels and larger hippocampi, both of which are associated with reduced Alzheimer’s risk. Conversely, those with mild cognitive impairment or dementia exhibited weaker vascular function compared to their cognitively normal peers. This aligns with the growing understanding that Alzheimer’s involves a complex interplay between vascular health and neurodegenerative changes.
The study highlights the importance of monitoring brain blood flow and oxygen delivery as part of Alzheimer’s risk assessment. These non-invasive tools could be particularly valuable for large-scale screening or for individuals who cannot undergo more intensive imaging procedures. While the research provides promising insights, it also underscores the need for longitudinal studies to determine whether changes in vascular measures can predict future cognitive decline or treatment response.
This breakthrough offers hope for earlier and broader detection of Alzheimer’s, potentially enabling interventions that could slow disease progression. By focusing on vascular health, researchers may open new avenues for understanding and combating Alzheimer’s, which currently affects millions worldwide. The study adds to the growing body of evidence suggesting that Alzheimer’s involves significant vascular contributions in addition to its well-known neurodegenerative changes.
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Originally published on Science Daily on 2/24/2026