title: Synchronization between arterial blood pressure and cerebral oxyhaemoglobin concentration investigated by wavelet cross-correlation.
abstract: Wavelet cross-correlation (WCC) is used to analyse the relationship between low-frequency oscillations in near-infrared spectroscopy (NIRS) measured cerebral oxyhaemoglobin (O(2)Hb) and mean arterial blood pressure (MAP) in patients suffering from autonomic failure and age-matched controls. Statistically significant differences are found in the wavelet scale of maximum cross-correlation upon posture change in patients, but not in controls. We propose that WCC analysis of the relationship between O(2)Hb and MAP provides a useful method of investigating the dynamics of cerebral autoregulation using the spontaneous low-frequency oscillations that are typically observed in both variables without having to make the assumption of stationarity of the time series. It is suggested that for a short-duration clinical test previous transfer-function-based approaches to analyse this relationship may suffer due to the inherent nonstationarity of low-frequency oscillations that are observed in the resting brain.
authors.affiliation: Department of Engineering Science, University of Oxford, Oxford, UK. abr@robots.ox.ac.uk
authors.forename: A B
authors.initials: AB
authors.lastname: Rowley
authors.forename: S J
authors.initials: SJ
authors.lastname: Payne
authors.forename: I
authors.initials: I
authors.lastname: Tachtsidis
authors.forename: M J
authors.initials: MJ
authors.lastname: Ebden
authors.forename: J P
authors.initials: JP
authors.lastname: Whiteley
authors.forename: D J
authors.initials: DJ
authors.lastname: Gavaghan
authors.forename: L
authors.initials: L
authors.lastname: Tarassenko
authors.forename: M
authors.initials: M
authors.lastname: Smith
authors.forename: C E
authors.initials: CE
authors.lastname: Elwell
authors.forename: D T
authors.initials: DT
authors.lastname: Delpy
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001342:Autonomic Nervous System Diseases / Q000378:metabolism / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology*; D001923:Brain Chemistry / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010108:Oxyhemoglobins / Q000032:analysis*; D010991:Plethysmography; D019265:Spectroscopy, Near-Infrared; D016683:Supine Position / Q000502:physiology; D018667:Tilt-Table Test
chemical_list: D010108:Oxyhemoglobins