title: Oscillations in cerebral blood flow and cortical oxygenation in Alzheimer's disease.
abstract: In Alzheimer's disease (AD) cerebrovascular function is at risk. Transcranial Doppler, near-infrared spectroscopy, and photoplethysmography are noninvasive methods to continuously measure changes in cerebral blood flow velocity (CBFV), cerebral cortical oxygenated hemoglobin (O(2)Hb), and blood pressure (BP). In 21 patients with mild to moderate AD and 20 age-matched controls, we investigated how oscillations in cerebral blood flow velocity (CBFV) and O(2)Hb are associated with spontaneous and induced oscillations in blood pressure (BP) at the very low (VLF = 0.05 Hz) and low frequencies (LF = 0.1 Hz). We applied spectral and transfer function analysis to quantify dynamic cerebral autoregulation and brain tissue oxygenation. In AD, cerebrovascular resistance was substantially higher (34%, AD vs. control: Δ = 0.69 (0.25) mm Hg/cm/second, p = 0.012) and the transmission of very low frequency (VLF) cerebral blood flow (CBF) oscillations into O(2)Hb differed, with increased phase lag and gain (Δ phase 0.32 [0.15] rad; Δ gain 0.049 [0.014] μmol/cm/second, p both < 0.05). The altered transfer of CBF to cortical oxygenation in AD indicates that properties of the cerebral microvasculature are changed in this disease.
authors.affiliation: Department of Geriatric Medicine, Alzheimer Centre Nijmegen and Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands.
authors.forename: Arenda H E A
authors.initials: AH
authors.lastname: van Beek
authors.forename: Joep
authors.initials: J
authors.lastname: Lagro
authors.forename: Marcel G M
authors.initials: MG
authors.lastname: Olde-Rikkert
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.forename: Jurgen A H R
authors.initials: JA
authors.lastname: Claassen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology*; D001683:Biological Clocks; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001921:Brain / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption
chemical_list: D010100:Oxygen