Individual variability of cerebral autoregulation, posterior cerebral circulation and white matter hyperintensity.

Key Points: Cerebral autoregulation (CA) is a key mechanism to protect brain perfusion in the face of changes in arterial blood pressure, but little is known about individual variability of CA and its relationship to the presence of brain white matter hyperintensity (WMH) in older adults, a type of white matter lesion related to cerebral small vessel disease (SVD). This study demonstrated the presence of large individual variability of CA in healthy older adults during vasoactive drug-induced changes in arterial pressure assessed at the internal carotid and vertebral arteries. We also observed, unexpectedly, that it was the 'over-' rather than the 'less-reactive' CA measured at the vertebral artery that was associated with WMH severity.

Amyloid burden and sleep blood pressure in amnestic mild cognitive impairment.

Objective: To determine whether cortical β-amyloid (Aβ) deposition is associated with circadian blood pressure (BP) profiles and dynamic cerebral blood flow (CBF) regulation in patients with amnestic mild cognitive impairment (aMCI).

Methods: Forty participants with aMCI were included in this study. Cortical Aβ depositions were measured by (18)F-florbetapir PET and expressed as the standardized uptake value ratio (SUVR) relative to the cerebellum.

Central artery stiffness, baroreflex sensitivity, and brain white matter neuronal fiber integrity in older adults.

Cerebral hypoperfusion elevates the risk of brain white matter (WM) lesions and cognitive impairment. Central artery stiffness impairs baroreflex, which controls systemic arterial perfusion, and may deteriorate neuronal fiber integrity of brain WM. The purpose of this study was to examine the associations among brain WM neuronal fiber integrity, baroreflex sensitivity (BRS), and central artery stiffness in older adults.

Dynamic cerebral autoregulation and tissue oxygenation in amnestic mild cognitive impairment.

Background: Vascular disease and dysfunction are associated with the higher risk of Alzheimer's disease hypothetically due to cerebral hypoperfusion. Brain perfusion is protected by cerebral autoregulation, which, under normal conditions, maintains a constant cerebral blood flow and brain tissue oxygenation.

Objective: To determine whether dynamic regulation of cerebral blood flow and tissue oxygenation is impaired in patients with amnestic mild cognitive impairment (aMCI).

Cerebral autoregulation of blood velocity and volumetric flow during steady-state changes in arterial pressure.

The validity of using transcranial Doppler measurement of cerebral blood flow velocity (CBFV) to assess cerebral autoregulation (CA) still is a concern. This study measured CBFV in the middle cerebral artery using transcranial Doppler and volumetric cerebral blood flow (CBF) in the internal carotid artery (ICA) using color-coded duplex ultrasonography to assess CA during steady-state changes in mean arterial pressure (MAP). Twenty-one healthy adults participated.