Point-Counterpoint: Transfer function analysis of dynamic cerebral autoregulation: To band or not to band?

• Published in: Journal of cerebral blood flow and metabolism Vol. 43; no. 9; pp. 1628 - 1630
• Main Authors: Liu, Jia, Simpson, David M, Panerai, Ronney B
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.09.2023
• Subjects: Blood Flow Velocity - physiology; Blood Pressure - physiology; Carbon Dioxide; Cerebrovascular Circulation - physiology; Commentaries; Homeostasis - physiology; Humans; blood flow velocity; transfer function analysis; Arterial blood pressure; cerebral autoregulation; frequency band
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1177/0271678X221098448

Transfer function analysis (TFA) is the most frequently adopted method for assessing dynamic cerebral autoregulation (CA) with continuously recorded arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV). Conventionally, values of autoregulatory metrics (e.g., gain and phase) derived from TFA are averaged within three frequency bands separated by cut-off frequencies at 0.07 Hz and 0.20 Hz, respectively, to represent the efficiency of dynamic CA. However, this is of increasing concerns, as there remains no solid evidence for choosing these specific cut-off frequencies, and the rigid adoption of these bands can stifle further developments in TFA of dynamic CA. In this ‘Point-Counterpoint’ mini-review, we provide evidence against the fixed banding, indicate possible alternatives, and call for awareness of the risk of the ‘one-size-fits-all’ banding becoming dogmatic. We conclude that we need to remain open to the multiple possibilities offered by TFA to realize its full potential in studies of human dynamic CA.