Clinical Implications of Fluctuations and Rhythms in Biological Signals

生物在不同的时间尺度上表现出波动和节奏，这些时间尺度与诸如生成、发育、成熟和老化等非平稳过程有关。在医学治疗中，重要的是要考虑生物信号的非平稳、有节奏和波动的方面。本研究试图在长期记录和分析技术的基础上，实现准确的诊断和有效的医疗治疗。结果如下：(1)在正常人心率变异中，在10^~(-3)~10^~(-2)~10^~(-2)~(-2)~(-2)~(-3)~(-3)~(-2)~(-1)~(-3)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-3)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)~(-1)。(2)48小时记录的高血压病患者夜间血压与左心室肥厚显著相关。(3)心绞痛患者的心理出汗测量有助于观察与胸痛相关的心理应激的反应过程。(4)胃电(EGG)显示胃上部起搏器的电活动(3次/分钟)。糖尿病自主神经系统疾病患者的EGG表现为一种湍流模式。(5)复杂解调技术对于分析非平稳信号频谱成分的波动是有用的。此外，新提出的分析技术有助于从生物信号中提取有用的信息。

Living things exhibit fluctuations and rhythms with various time scales associated with nonstationary processes such as generation, developing, maturing, and aging. In a medical treatment, it should be essential to consider nonstationary, rhythmic, and fluctuating aspects of biological signals. In this research, a precise diagnosis and an efficient medical treatment were attempted to be achieved based on a long-term recording and analysis techniques. Results are summarized as follows.(1) In the heart rate variabilities of normal human subjects, deviations from the 1/f spectral profile were observed in the frequency range from 10^<-3> to 10^<-2>Hz, which was supposed to reflact the cardiovascular dynamics during slow wave sleep.(2) The 48hr recording of blood pressure of essential hypertensive patients showed the significant correlation between the "Non-dipper" group during night and left ventricular hypertrophy.(3) The measurement of psychologic sweating for angina patients was shown to be useful to observe the responsive process to the psychological stress associated with the thoracic pain.(4) Electrogastrograph (EGG) was shown to reflect the electrical activity (3 times/min) of pacemakers located on the upper side of the stomach. The patients with diabetic autonomic nervous system disease were found to show a turbulant pattern of EGG.(5) The complex demodulation technique was shown to be useful for analysing fluctuations in spectral components of nonstationary signals.The results obtained here clarify the clinical implications of fluctuations and rhythms in biological signals. Besides, the newly proposed analysis techniques could contribute to extracting useful information from biological signals.