Yacin S, Manivannan M, Chakravarthy V
Biomedical Engineering Group, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai-600036, India.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:2639-42. doi: 10.1109/IEMBS.2009.5335365.
Photoplethysmography (PPG) is typically used to extract cardiac-related information like heart rate and cardiac output, though extra-cardiac information like respiratory rate can also be extracted from PPG. The aim of the current study is to advance this approach further and investigate existence of gastric-related activity in PPG. To this end, we consider pulse rate variability (PRV), which provides information analogous to heart rate variability (HRV). Finger PPG and electrogastrography (EGG) signals were recorded from 8 healthy volunteers in fasting and postprandial state for 30 minutes. Peak-to-peak interval (PPI) analysis shows that the power of high frequency (HF) component in fasting and postprandial state changes significantly. The power ratio (PR), which is the ratio between powers of low frequency band (LF, 0.04-0.15 Hz) to that of high frequency band (HF, 0.15-0.4 Hz) and the EGG power were calculated in fasting and postprandial state. PR was positively correlated with EGG power (r = 0.46; P< 0.05). PR indicates the balancing sympathovagal modulation and vagal nervous activity. The significance of this study is that PR from PRV analysis could be used as a tool for diagnosing gastric system instead of the present invasive/cumbersome methods.
光电容积脉搏波描记法（PPG）通常用于提取与心脏相关的信息，如心率和心输出量，不过像呼吸频率这样的心脏外信息也可以从PPG中提取。本研究的目的是进一步推进这种方法，并研究PPG中与胃相关活动的存在情况。为此，我们考虑脉搏率变异性（PRV），它提供与心率变异性（HRV）类似的信息。从8名健康志愿者在空腹和餐后状态下记录了30分钟的手指PPG和胃电图（EGG）信号。峰峰值间隔（PPI）分析表明，空腹和餐后状态下高频（HF）成分的功率有显著变化。计算了空腹和餐后状态下低频带（LF，0.04 - 0.15Hz）与高频带（HF，0.15 - 0.4Hz）功率之比的功率比（PR）以及EGG功率。PR与EGG功率呈正相关（r = 0.46；P < 0.05）。PR表明交感神经 - 迷走神经调制和迷走神经活动的平衡。本研究的意义在于，PRV分析中的PR可作为诊断胃系统的工具，而非目前的侵入性/繁琐方法。
