Valenza Gaetano, Iozzia Luca, Cerina Luca, Mainardi Luca, Barbieri Riccardo
Annu Int Conf IEEE Eng Med Biol Soc. 2017 Jul;2017:1776-1779. doi: 10.1109/EMBC.2017.8037188.
Although there is growing interest in estimating cardiovascular information using contactless video plethysmography (VP), an in-depth validation of time-varying, nonlinear dynamics of the related pulse rate variability is still missing. In this study we estimate the heartbeat through VP and standard ECG, and employ inhomogeneous point-process nonlinear models to assess instantaneous heart rate variability measures defined in the time, frequency, and bispectral domains. Experimental data were gathered from 60 young healthy subjects (age: 24±3 years) undergoing postural changes (rest-to-stand maneuver). Video recordings are processed using our recently proposed method based on zero-phase component analysis. Results show that, at a group level, there is an overall agreement between linear and nonlinear indices computed from ECG and VP during resting state conditions. However, significant differences are found, especially in the bispectral domain, when considering data gathered while standing. Although significant differences exist between cardiovascular estimates from VP and ECG, results can be considered very promising as instantaneous sympatho-vagal changes were correctly identified. More research is indeed needed to improve on the precise estimation of nonlinear sympatho-vagal interactions.
尽管利用非接触式视频体积描记法（VP）估算心血管信息的兴趣与日俱增，但对相关心率变异性的时变、非线性动力学的深入验证仍付诸阙如。在本研究中，我们通过VP和标准心电图估算心跳，并采用非齐次点过程非线性模型来评估在时间、频率和双谱域中定义的瞬时心率变异性指标。实验数据收集自60名年轻健康受试者（年龄：24±3岁），他们正在经历姿势变化（从静息到站立动作）。视频记录使用我们最近提出的基于零相位分量分析的方法进行处理。结果表明，在群体水平上，静息状态下从心电图和VP计算出的线性和非线性指标总体上是一致的。然而，在考虑站立时收集的数据时，发现了显著差异，尤其是在双谱域。尽管从VP和心电图得出的心血管估算值之间存在显著差异，但由于瞬时交感-迷走神经变化被正确识别，结果可被视为非常有前景。确实需要更多研究来改进对非线性交感-迷走神经相互作用的精确估算。
