Panerai R B, Rennie J M, Kelsall A W, Evans D H
Division of Medical Physics, Faculty of Medicine, University of Leicester, Leicester Royal Infirmary, UK.
Med Biol Eng Comput. 1998 May;36(3):315-22. doi: 10.1007/BF02522477.
The dynamic relationship between spontaneous fluctuations of arterial blood pressure (ABP) and corresponding changes in cerebral blood flow velocity (CBFV) is studied in a population of 83 neonates. Static and dynamic methods are used to identify two subgroups showing either normal (group A, n = 23) or impaired (group B, n = 21) cerebral autoregulation. An FFT algorithm is used to estimate the coherence and transfer function between CBFV and ABP. The significance of the linear dependence between these two variables is demonstrated by mean values of squared coherence > 0.50 for both groups in the frequency range 0.02-0.50 Hz. However, group A has significantly smaller coherences than group B in the frequency ranges 0.02-0.10 Hz and 0.33-0.49 Hz. The phase response of group A is also significantly more positive than that of group B, with slopes of 9.3 +/- 1.05, and 1.80 +/- 1.2 rad Hz-1, respectively. The amplitude frequency response is also significantly smaller for group A in relation to group B for the frequency range 0.25-0.43 Hz. These results suggest that transfer function analysis may be able to identify different components of cerebral autoregulation and also provide a deeper understanding of recent findings by other investigators.
在83名新生儿群体中研究了动脉血压（ABP）的自发波动与脑血流速度（CBFV）相应变化之间的动态关系。采用静态和动态方法识别出两个亚组，分别显示正常（A组，n = 23）或受损（B组，n = 21）的脑自动调节功能。使用快速傅里叶变换（FFT）算法估计CBFV与ABP之间的相干性和传递函数。在0.02 - 0.50 Hz频率范围内，两组的平方相干性平均值> 0.50，证明了这两个变量之间线性依赖的显著性。然而，在0.02 - 0.10 Hz和0.33 - 0.49 Hz频率范围内，A组的相干性明显小于B组。A组的相位响应也明显比B组更正向，斜率分别为9.3 +/- 1.05和1.80 +/- 1.2 rad Hz-1。在0.25 - 0.43 Hz频率范围内，A组的幅度频率响应相对于B组也明显更小。这些结果表明，传递函数分析可能能够识别脑自动调节的不同组成部分，并能更深入地理解其他研究者最近的发现。
