A method based on an octave-band analysis with an R-wave detector to analyze heart rate variability for evaluation of mental strain

Abstract

A method based on an octave-band analysis is provided to perform real-time analysis of Heart Rate Variability (HRV) on a personal computer with high temporal resolution. This method requires a hardware and a software besides the computer. The hardware (R-wave detector) generates pulses synchronized with R-waves from an Electro Cardiogram (ECG) signal. And the software calculates spectral power within each of passbands by using four sets of digital band-pass filters. As outputs of the analysis, normalized spectral powers for these passbands and an HRV index are obtained. The HRV index is calculated as a weighted sum of the normalized spectral powers. With some modifications, this method is also applicable to a Holter EGG signal recorded on a tape.
This method was applied to EGG signals obtained through two VDT experiments employing a location task and a manual control task. In this paper, the method is explained in detail. Moreover, based on results obtained through those applications, aptness of the method is also discussed as to evaluate mental strain.