Synchronization between arterial blood pressure and cerebral oxyhaemoglobin concentration investigated by wavelet cross-correlation.
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.
Rowley
A B
AB
Department of Engineering Science, University of Oxford, Oxford, UK. abr@robots.ox.ac.uk
Payne
S J
SJ
Tachtsidis
I
I
Ebden
M J
MJ
Whiteley
J P
JP
Gavaghan
D J
DJ
Tarassenko
L
L
Smith
M
M
Elwell
C E
CE
Delpy
D T
DT
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
D010108:Oxyhemoglobins