Valenza Gaetano, Greco Alberto, Scilingo Enzo Pasquale, Barbieri Riccardo
Annu Int Conf IEEE Eng Med Biol Soc. 2017 Jul;2017:3765-3768. doi: 10.1109/EMBC.2017.8037676.
Nonlinear analysis has been advocated as a very powerful methodological framework to study physiological signals, particularly when applied to heartbeat dynamics. To this extent, estimation of high-frequency (0.15-0.40 Hz) power from bispectra of cardiovascular variability series has been engaged as a marker of nonlinear vagal activity. Nevertheless, a proper validation of this specific measure has not been yet performed. In this study, we estimate instantaneous, nonlinear bispectral indices during postural changes under sympathetic and parasympathetic nervous system blockade. The analysis was performed on data from 14 healthy subjects undergoing a control supine-to-upright routine where they were selectively administered either atropine or propanolol. Instantaneous bispectra were obtained through Laguerre-transformed, linear and nonlinear kernels of a Wiener-Volterra model applied to heartbeat dynamics, embedded into a recently proposed inhomogeneous point-process framework. Results demonstrate that the integration of bispectra accounting for nonlinear cardiovascular control dynamics within the high-frequency band provides potentially reliable markers of vagal activity.
非线性分析已被倡导为一种研究生理信号的非常强大的方法框架，特别是应用于心跳动力学时。在此范围内，从心血管变异性系列双谱估计高频（0.15 - 0.40赫兹）功率已被用作非线性迷走神经活动的标志物。然而，尚未对这一特定测量方法进行适当验证。在本研究中，我们在交感神经和副交感神经系统阻滞下的姿势变化过程中估计瞬时非线性双谱指数。分析是对14名健康受试者的数据进行的，这些受试者进行了从仰卧到直立的常规对照实验，在实验中他们被选择性地给予阿托品或普萘洛尔。通过应用于心跳动力学的维纳 - 沃尔泰拉模型的拉盖尔变换线性和非线性核获得瞬时双谱，并将其嵌入到最近提出的非齐次点过程框架中。结果表明，在高频带内考虑非线性心血管控制动力学的双谱积分提供了潜在可靠的迷走神经活动标志物。
