Department of Clinical Neurophysiology, University Hospital Maastricht, Maastricht, The Netherlands.
Med Biol Eng Comput. 2010 Dec;48(12):1243-50. doi: 10.1007/s11517-010-0706-y. Epub 2010 Nov 4.
Cerebral autoregulation controls cerebral blood flow under changing cerebral perfusion pressure. Standards for measurement and analysis of dynamic cerebral autoregulation (dCA) are lacking. In this study, dCA reproducibility, quantified by intraclass correlation coefficient, is evaluated for different methodological approaches of transfer function analysis (TFA) and compared with multimodal pressure flow analysis (MMPF). dCA parameters were determined in 19 healthy volunteers during three 15-min lasting epochs of spontaneous breathing. Every spontaneous breathing epoch was followed by 5 min of paced breathing at 6 cycles/min. These six measurements were performed in both a morning and an afternoon session. Analysis compared raw data pre-processing by mean subtraction versus smoothness priors detrending. The estimation of spectral density was either performed by averaging of subsequent time windows or by smoothing the spectrum of the whole recording. No significant influence of pre-processing and spectral estimation on dCA parameters was found. Therefore, there seems to be no need to prescribe a specific signal-processing regime. Poor reproducibility of gain and phase was found for TFA as well as for MMPF. Based on reproducibility, no preference can be made for morning versus afternoon measurements, neither for spontaneous versus paced breathing. Finally, reproducibility results are not in favour of TFA or MMPF.
脑自动调节控制脑血流在不断变化的脑灌注压下。目前缺乏用于测量和分析动态脑自动调节（dCA）的标准。在这项研究中，通过组内相关系数评估了转移函数分析（TFA）不同方法学方法的 dCA 可重复性，并与多模态压力流分析（MMPF）进行了比较。在 19 名健康志愿者中，在三个 15 分钟的自主呼吸期间确定了 dCA 参数。每个自主呼吸期后，进行 5 分钟的 6 次/分钟的有节奏呼吸。这六次测量分别在上午和下午进行。分析比较了均值减去预处理和平滑优先去趋势的原始数据预处理。通过随后的时间窗口的平均或通过对整个记录的频谱进行平滑来进行频谱密度的估计。未发现预处理和谱估计对 dCA 参数有显著影响。因此，似乎不需要规定特定的信号处理方案。TFA 和 MMPF 均发现增益和相位的可重复性差。基于可重复性，不能优先选择上午或下午的测量值，也不能优先选择自主呼吸或有节奏呼吸。最后，可重复性结果不利于 TFA 或 MMPF。
