Development of HR monitoring system and its application to evaluation of responses in persons with profound brain dysfunction.

患有严重脑功能障碍的人的行为反应非常有限。心理生理指标可用于评估其注意过程和认知特性。本研究的目的是开发一种心率监测系统，并评估严重脑功能障碍患者的心率反应。第一个方面是注意要求情境下的阶段性HR变化。第二个方面是呼吸性窦性心律失常（RSA）。为了利用这些HR指标来评价注意过程，需要对HR反应进行真实的实时检测。在本研究中，开发了一种用于心电图遥测和HR反应检测的系统。发射器系统放大ECG并通过电磁感应产生持续时间等于ECG的R波和R波之间的间隔的脉冲。接收器接收脉冲并将R波出现的信息传送到个人计算机。打印机端口被用作接收器和计算机之间的接口。计算机接收事件标记，并显示与事件标记开始相关的心率变化。对于RSA，通过最大熵方法将连续20秒的心率转换为频谱。通过使用本研究开发的系统，可以监测注意过程，并证实了该系统的效率。对HR反应的实时评估可能使监测具有严重脑功能障碍的人的注意过程成为可能。该监控系统被认为有助于保持这些人与教师之间的沟通。

Persons with profound brain dysfunction are quite restricted with their behavioral responses. Psychophysiological indices are useful for assessments of their attention process and cognitive properties. The purpose of this study was to development a heart rate (HR) monitoring system, and to evaluate HR responses in persons with profound brain dysfunction.Two aspects of HR responses relate to level of attention. The first aspect concerns phasic HR changes during attention demanding situation. The second aspect is respiratory sinus arrhythmia(RSA). This aspect relates to the sustained or tonic-focussed attention.In order to use these HR indices for evaluating attention process, real time detection for HR responses is needed. In the present study, a system was developed for telemetry of ECGs and detection of HR responses. A system of transmitter amplified ECGs and generated pulses with duration which was equal to an interval between R-wave and R-wave of ECGs through the electromagnetic induction. A receiver received pulses and conveyed information of the occurrence of R-wave to a personal computer. A printer-port was used as an interface between a receiver and a computer. The computer received an event mark and displayed change of heart rates in relation to the onset of an event mark. In regard to RSA, successive heart rate of 20 seconds were transformed to an spectrum through the maximum entropy method. Display of an spectrum was renewed after an elapse of 20 seconds.Through using the system developed in the present study, attention process could be monitored and efficiency of this system was confirmed. Real-time evaluation of HR responses might enable monitoring attention process in persons with profound brain dysfunction. This monitoring system is thought to be helpful in maintaining communication between these persons and there teacher.