Dynamic cerebral autoregulation and tissue oxygenation in amnestic mild cognitive impairment (1068.7)

Abstract

Background: Vascular disease and dysfunction elevate the risk of Alzheimer’s disease. The objective of this study was to determine whether dynamic regulation of cerebral blood flow and tissue oxygenation is impaired in patients with amnestic mild cognitive impairment (aMCI). Methods: Twenty‐seven patients with aMCI and 15 control subjects underwent measurements of cerebral hemodynamics, brain MRI, and neurocognitive assessment. Dynamic cerebral autoregulation and tissue oxygenation were assessed by transfer function analysis of mean blood pressure (MBP), normalized cerebral blood flow velocity (CBFV%), and cerebral tissue oxygenation index (TOI) at baseline and during a sit‐stand maneuver. Results: Patients with aMCI demonstrated lower cognitive performance in memory and executive function, accompanied by smaller volumes of entorhinal cortex. At baseline, aMCI patients exhibited lower levels of cerebral TOI. Transfer function gain and phase between MBP and CBFV% and between CBFV% and cerebral TOI did not differ between the groups. Within aMCI patients, greater oscillations and transfer function gain of cerebral TOI were associated with the lower scores on delayed recall. Conclusions: An inverse association between transfer function gain of cerebral TOI and memory performance suggests impairment of oxygen transport from the microcirculation to brain tissue in patients with aMCI.Grant Funding Source: National Institute on Aging