title: How measurement artifacts affect cerebral autoregulation outcomes: A technical note on transfer function analysis.
abstract: Cerebral autoregulation (CA) is the mechanism that aims to maintain adequate cerebral perfusion during changes in blood pressure (BP). Transfer function analysis (TFA), the most reported method in literature to quantify CA, shows large between-study variability in outcomes. The aim of this study is to investigate the role of measurement artifacts in this variation. Specifically, the role of distortion in the BP and/or CBFV measurementon TFA outcomes was investigated. The influence of three types of artifacts on TFA outcomes was studied: loss of signal, motion artifacts, and baseline drifts. TFA metrics of signals without the simulated artifacts were compared with those of signals with artifacts. TFA outcomes scattered highly when more than 10% of BP signal or over 8% of the CBFV signal was lost, or when measurements contained one or more artifacts resulting from head movement. Furthermore, baseline drift affected interpretation of TFA outcomes when the power in the BP signal was 5 times the power in the LF band. In conclusion, loss of signal in BP and loss in CBFV, affects interpretation of TFA outcomes. Therefore, it is vital to validate signal quality to the defined standards before interpreting TFA outcomes.
authors.affiliation: Radboud University Medical Centre, Donders institute for Brain Cognition and Behaviour, Radboud Alzheimer Centre, and Department of Geriatric Medicine, Reinier Postlaan 4, 6525 GC, Nijmegen, the Netherlands.
authors.forename: Aisha S S
authors.initials: AS
authors.lastname: Meel-van den Abeelen
authors.affiliation: Radboud University Medical Centre, Donders institute for Brain Cognition and Behaviour, Radboud Alzheimer Centre, and Department of Geriatric Medicine, Reinier Postlaan 4, 6525 GC, Nijmegen, the Netherlands; University of Twente, MIRA institute for Biomedical Technology and Technical Medicine, Enschede, the Netherlands.
authors.forename: Daan L K
authors.initials: DL
authors.lastname: de Jong
authors.affiliation: Radboud University Medical Centre, Donders institute for Brain Cognition and Behaviour, Radboud Alzheimer Centre, and Department of Geriatric Medicine, Reinier Postlaan 4, 6525 GC, Nijmegen, the Netherlands.
authors.forename: Joep
authors.initials: J
authors.lastname: Lagro
authors.affiliation: Leicester Royal Infirmary, NIHR Biomedical Research Unit in Cardiovascular Sciences, Glenfield Hospital, Leicester LE2 7LX, UK.
authors.forename: Ronney B
authors.initials: RB
authors.lastname: Panerai
authors.affiliation: Radboud University Medical Centre, Donders institute for Brain Cognition and Behaviour, Radboud Alzheimer Centre, and Department of Geriatric Medicine, Reinier Postlaan 4, 6525 GC, Nijmegen, the Netherlands. Electronic address: Jurgen.Claassen@radboudumc.nl.
authors.forename: Jurgen A H R
authors.initials: JA
authors.lastname: Claassen
mesh_terms: D016477:Artifacts; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001795:Blood Pressure Determination; D002560:Cerebrovascular Circulation; D006706:Homeostasis; D006801:Humans; D009068:Movement; D012815:Signal Processing, Computer-Assisted; D013223:Statistics as Topic
keywords: Cerebral autoregulation; Signal-to-noise ratio; Transfer function analysis