title: Dynamic cerebral autoregulation and tissue oxygenation in amnestic mild cognitive impairment.
abstract: 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).
  
  
  METHODS
  Twenty-seven patients with aMCI and 15 control subjects with normal cognitive function underwent the measurements of cerebral hemodynamics, brain MR imaging, and neurocognitive assessment. Dynamic regulation of cerebral blood flow and tissue oxygenation were assessed by transfer function analysis of changes in 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 entorhinal cortex volumes. At baseline, cerebral TOI was lower in patients with aMCI than in control subjects. Lower cerebral TOI was also correlated with lower cognitive performance in memory and executive function in all subjects. Transfer function gain and phase between MBP and CBFV% and between CBFV% and cerebral TOI were not different between the groups. Within aMCI patients, greater oscillations of cerebral TOI and higher transfer function gain between cerebral TOI and CBFV% were associated with the lower scores on delayed recall.
  
  
  CONCLUSIONS
  Dynamic regulation of cerebral tissue oxygenation is associated with neurocognitive dysfunction in aMCI patients.
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA Department of Internal Medicine, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tarumi
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.
authors.forename: David I
authors.initials: DI
authors.lastname: Dunsky
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA Department of Internal Medicine, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: M Ayaz
authors.initials: MA
authors.lastname: Khan
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA Department of Internal Medicine, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.
authors.forename: Candace
authors.initials: C
authors.lastname: Hill
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Armstrong
authors.affiliation: Department of Psychiatry, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Kristin
authors.initials: K
authors.lastname: Martin-Cook
authors.affiliation: Department of Psychiatry, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA Department of Neurology and Neurotherapeutics, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: C Munro
authors.initials: CM
authors.lastname: Cullum
authors.affiliation: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA Department of Internal Medicine, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA Department of Neurology and Neurotherapeutics, Alzheimer's Disease Center, University of Texas Southwestern Medical Center, Dallas, TX, USA.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D016009:Chi-Square Distribution; D060825:Cognitive Dysfunction / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism* / Q000473:pathology; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017711:Nonlinear Dynamics; D010100:Oxygen / Q000378:metabolism*; D012039:Regional Blood Flow
chemical_list: D010100:Oxygen
keywords: Alzheimer's disease; cerebral autoregulation; cerebral blood flow; cerebral tissue oxygenation; mild cognitive impairment