Understanding cognitive decline among elderly with Dementia using the “Heart-to-Brain Connection”
Published: 31 May 2023
While investigating the relationship between cardiovascular function and brain health and cognition among the elderly at-risk for dementia in Singapore, NUS researchers found that cardiovascular dysfunction could lead to cerebrovascular dysfunction processes, which may ultimately result in dementia and cognitive decline.
In recent years, there has been greater awareness of the “heart-brain connection” in our body, or the impact of cardiovascular function on brain health and cognition.
However, the relationships between circulating cardiovascular markers — which are substances that are released into the blood when the heart is damaged or stressed; and cerebrovascular function — which refers to the ability of the cerebral blood vessels to deliver oxygen and nutrients for neural activity; for underlying cognitive decline, are not yet fully understood.
At the same time, brain free-water is a novel imaging marker that is useful for detecting early and subtle cerebrovascular dysfunction. Detected by diffusion MRI, free water could provide valuable insights into disease progression and response to therapy.
Homing in on the relationship between cardiovascular markers and cerebrovascular function, Associate Professor Helen Zhou from the Centre for Sleep and Cognition in NUS Medicine, and Director, Center for Translational MR Research at the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), together with Dr Mitchell Lai from the Department of Pharmacology and Principal Investigator at the Memory, Aging and Cognition Center at NUS Medicine, led a study to investigate the neural mechanism guiding the relationship between cardiovascular dysfunction and cognitive decline in the Singaporean elderly. The study was conducted on the elderly with normal cognition, mild cognitive impairment and dementia. The researchers found that three blood cardiovascular biomarkers were associated with higher brain free-water, indicating a higher change of decline in neural function. The paper is published in Neurology.
The researchers found that cardiovascular dysfunction could lead to alterations in brain vasculature, affecting small arteries, arterioles, and capillaries, as well as causing neurovascular changes. These changes can instigate cerebrovascular dysfunction processes, which may lead to neuronal damage, synaptic loss, and neurodegeneration, ultimately resulting in dementia and cognitive decline.
Thus, their findings suggest the role of brain free-water in linking cardiovascular dysfunction to longitudinal cognitive decline. Free-water alterations might be one of the early underlying mechanisms of brain network degeneration in dementia patients, which eventually influences domain-specific cognitive functions.
“The prevalence of dementia will double every 20 years. At the same time, there is a high prevalence of cerebrovascular disease (CeVD) among patients with mild cognitive impairment (MCI) and dementia in Singapore. CeVD often appears together with vascular dementia or Alzheimer’s disease (AD). AD with CeVD is the most common type of dementia in Asia, including Singapore,” said Associate Professor Zhou.
Clinically, the assessment of free-water in specific brain networks together with the blood test of cardiovascular biomarkers could be helpful for the personalised prediction of cardiovascular and cerebrovascular disease progression and domain-specific cognitive decline.
Click here to read the press release.
