Optimization of the Coherence Measurement Computed by Means of the Welch Averaged Periodogram Method for Assessment of Impaired Cerebral Autoregulation
The coherence method (COH) has been widely used to study the concordance between continuously measured signals intervening in the assessment of cerebral autoregulation in neonates. Several research groups have applied this method to mean arterial blood pressure (MABP) combined with cerebral signals such as the intravascular oxygenation (HbD), cerebral tissue oxygenation (TOI), and regional oxygen saturation (rSO2) measured by near-infrared spectroscopy (NIRS). All groups contributed in a particular way to the fine-tuning of the application of COH with the Welch averaged periodogram (WAP) method. We have made a comparative study of all published results coupled with an optimization of the use of the WAP method within COH. We have also proposed a pre-processing algorithm to remove signal artefacts, and defined a new critical score value (CSV) for COH to distinguish infants with impaired autoregulation from those without.
KeywordsFast Fourier Transform Mean Arterial Blood Pressure Cerebral Oxygenation Hanning Window Signal Periodicity
The research was supported by: Research Council KUL: GOA AMBioRICS, CoE EF/05/006, by FWO projects G.0519.06 (Non-invasive brain oxygenation), and G.0341.07 (Data fusion), by Belgian Federal Science Policy Office IUAP P5/22. We thank particularly Prof. Frank van Bel and Dr. Petra Lemmers from the University Medical Centre Utrecht (The Netherlands), and PD Dr. Martin Wolf from the University Hospital Zurich (Switzerland) for having let us use their signal recordings.
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