Mechanisms underlying phase lag between systemic arterial blood pressure and cerebral blood flow velocity

Terry B.J. Kuo, Chang Ming Chern, Cheryl C.H. Yang, Hung Yi Hsu, Wen Jang Wong, Wen Yung Sheng, Han Hwa Hu

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


To explore the mechanisms underlying the phase lag between oscillations in arterial blood pressure (ABP) and cerebral blood flow velocity (CBFV), ABP and CBFV signals were recorded noninvasively from normal volunteers who lay quietly in a supine position. Mean ABP (MAP) and CBFV (MFV) were calculated beat-to-beat by means of integration. Cerebral vascular resistance (CVR) was calculated by dividing MAP with MFV. Frequency domain analysis of MAP, MFV and CVR signals revealed very-low frequency (VLF, 0.016-0.04 Hz), low-frequency (LF, 0.04-0.15 Hz), and high-frequency (HF, 0.15-0.4 Hz) components. The transfer phase of MAP-CVR coupling in the LF and HF range was frequency-dependent, which is equivalent to a time delay of 2 s. However, the transfer phase differed in the CVR-MFV coupling in that the phase was distributed around 180° across the LF and HF ranges. Cross-correlation analysis revealed a positive relationship between MAP-CVR coupling, with MAP leading by 2 s, and a negative relationship between CVR-MFV coupling, with CVR leading by 0.3 s. We concluded that the phase lag between oscillations in ABP and CBFV was chiefly contributed to by the starting latency of cerebral autoregulation (i.e. cerebral vasomotion, revealed by MAP-CVR coupling). Moreover, the negative correlation of the CVR-MFV coupling could offer a different explanation for the physiologic significance of the phase lead of CBFV-ABP oscillations.

Original languageEnglish
Pages (from-to)402-409
Number of pages8
JournalCerebrovascular Diseases
Issue number4
Publication statusPublished - 2003
Externally publishedYes


  • Cerebral autoregulation
  • Cerebral blood flow
  • Cross-correlation analysis
  • Middle cerebral artery
  • Transcranial Doppler sonography
  • Transfer function analysis

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine


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