title: Wavelet coherence analysis of dynamic cerebral autoregulation in neonatal hypoxic-ischemic encephalopathy.
abstract: Cerebral autoregulation represents the physiological mechanisms that keep brain perfusion relatively constant in the face of changes in blood pressure and thus plays an essential role in normal brain function. This study assessed cerebral autoregulation in nine newborns with moderate-to-severe hypoxic-ischemic encephalopathy (HIE). These neonates received hypothermic therapy during the first 72 h of life while mean arterial pressure (MAP) and cerebral tissue oxygenation saturation (SctO2) were continuously recorded. Wavelet coherence analysis, which is a time-frequency domain approach, was used to characterize the dynamic relationship between spontaneous oscillations in MAP and SctO2. Wavelet-based metrics of phase, coherence and gain were derived for quantitative evaluation of cerebral autoregulation. We found cerebral autoregulation in neonates with HIE was time-scale-dependent in nature. Specifically, the spontaneous changes in MAP and SctO2 had in-phase coherence at time scales of less than 80 min (< 0.0002 Hz in frequency), whereas they showed anti-phase coherence at time scales of around 2.5 h (~ 0.0001 Hz in frequency). Both the in-phase and anti-phase coherence appeared to be related to worse clinical outcomes. These findings suggest the potential clinical use of wavelet coherence analysis to assess dynamic cerebral autoregulation in neonatal HIE during hypothermia.
authors.affiliation: Department of Bioengineering, University of Texas at Arlington, United States.
authors.forename: Fenghua
authors.initials: F
authors.lastname: Tian
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, United States; Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, United States; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas, United States.
authors.forename: Takashi
authors.initials: T
authors.lastname: Tarumi
authors.affiliation: Department of Bioengineering, University of Texas at Arlington, United States.
authors.forename: Hanli
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Internal Medicine, University of Texas Southwestern Medical Center, United States; Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, United States; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas, United States.
authors.forename: Rong
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Pediatrics, University of Texas Southwestern Medical Center, United States. Electronic address: Lina.chalak@utsouthwestern.edu.
authors.forename: Lina
authors.initials: L
authors.lastname: Chalak
mesh_terms: D062186:Arterial Pressure / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis* / Q000503:physiopathology*; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010100:Oxygen / Q000097:blood; D019265:Spectroscopy, Near-Infrared / Q000379:methods
chemical_list: D010100:Oxygen
keywords: Cerebral autoregulation; Hypothermia; Hypoxic–ischemic encephalopathy (HIE); Near infrared spectroscopy (NIRS); Wavelet coherence