Resting-State Cerebral Blood Flow and Its Disconnect From Functional Connectivity in Alzheimer's Disease Spectrum

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Neurovascular coupling disruption is linked to Alzheimer's disease (AD) pathogenesis.
• Early changes in symptomatic AD patients require further clarification.

Purpose of the Study:

• To investigate neurovascular coupling in early Alzheimer's disease.
• To assess the utility of the cerebral blood flow to functional connectivity strength (CBF/FCS) ratio as a biomarker.

Main Methods:

• Studied 50 AD patients, 38 mild cognitive impairment (MCI) patients, and 50 controls.
• Utilized whole-brain functional connectivity strength (FCS) and cerebral blood flow (CBF) maps.
• Assessed global neurovascular coupling via CBF-FCS correlation and regional coupling via CBF/FCS ratio.

Main Results:

• Overall neurovascular coupling (CBF-FCS) declined gradually in AD patients compared to controls.
• Reduced regional CBF/FCS ratio observed in temporal and angular gyri in AD patients.
• Regional CBF/FCS in the inferior temporal gyrus correlated positively with visuospatial function in AD dementia.

Conclusions:

• Neurovascular decoupling is present in early AD and progresses with the disease.
• The CBF/FCS ratio shows potential as a biomarker for early AD diagnosis and clinical assessment.