Construction of Programmable Long-Term Measurement and Recording System for Biological Signals

为了研究心血管信号的波动和预测病理事件的发生，必须有一个系统能够在白天以外的长时间内实现稳定的测量和记录。本研究构建了这样一个系统。结果总结如下：1。所构建的便携式生物信号长期记录系统具有可达192MB的大规模存储、基于cmos电路实现的低功耗、可编程的测量模式等优点。第二套系统是在第一套系统的基础上进一步开发的，增强了数据传输接口，新增了监控系统内部状态的指标。为了排除心电信号中包含的基线缓慢波动，设计了多重数字陷波滤波器，并开发了用于提取R波和T波的专用算法。为了进一步分析EGG数据，提出了一种基于非平稳谱分析的新方法来阐明自主活动之间平衡的过渡规律。实现了双谱分析。估计心血管变量之间的脉冲响应，以表征心血管系统的状态依赖性。本文提出了心血管动力学之间的距离度量来定量区分状态相关的性质。在自由移动的环境下，包括睡眠和清醒状态在内的忠实测量和记录被确认保持长达32小时。受试者声称佩戴该系统时没有不舒服的感觉。该系统应用于睡眠呼吸暂停患者，在允许自由移动的情况下，用电容式麦克风代替加速度传感器来监测气管声音。该应用程序也显示了该系统对患者的满意可用性。

In order to investigate fluctuations in the cardiovascular signals and to predict occurrences of pathological events, a system is essential which realizes stable measurement and recording for a long period beyond the day length. In this study, such a system is constructed. The results are summarized as follows.1.The constructed portable long-term recording system for biological signals has the following merits including a large scale memory up to 192MB,low power consumption realized by CMOS-based circuits, programmable measurement modes. The 2nd system is additionally developed based on the experiences of the 1st one, where the interface for data transfer is enhanced and the indicators for monitoring the internal states of the system is newly equipped.2.The multiple digital notch filter is composed for excluding slow fluctuations of the baseline contained in ECG,and the special-purpose algorithms for extracting R and T waves are also developed.3.For further analyzes of EGG data, a novel method is developed to clarify a transition rule of the balance between the autonomic activities based on the nonstationary spectral analysis. The bispectral analysis is also implemented. Impulse responses between cardiovascular variables are estimated for chracterizing the state-dependency of the cardiovascular system. The distance measure between cardiovascular dynamics are newly proposed to quantitatively differentiate the state-dependent properties.4.Under the free-moving environment, faithful measurement and recording are confirmed to be maintained up to 32 hours including sleep and waking states. The subjects claim no uncomfortable feelings while wearing the system. The system is applied to the sleep apnea patient under allowed to move freely, where a condenser microphone is equipped instead of the acceleration sensor for monitoring tracheal sounds. This application shows satisfactory availability of the system for patients as well.