Assessment of emotional reaction induced by visual stimulation based on cross-correlation between pulse wave transmission time and heart rate in the Mayer wave-band

Mayer wave (0.1Hz fluctuation) included in heart rate variability and blood pressure variability appears apparently in the resting state. On the other hand, it can be predicted that a strong emotional reaction may affect the relationship between these variabilities. This prediction suggests that the human emotional reaction can be quantified by the maximum correlation coefficient ρ_max between heart rate and blood pressure whose frequency components are limited to the Mayer wave-band. However, the conventional method of obtaining ρ_max needs a bulky and expensive device for measuring continuous blood pressure. In this study, a smaller and cheaper device for measuring pulse wave transmission time (PTT) has been developed. This work has shown that the PTT can give ρ_max instead of blood pressure and that ρ_max obtained by the PTT may significantly reflect the emotional reaction on the basis of an experiment using nine healthy subjects with nine self-produced devices in which pictures were presented to the subjects to induce their emotional reactions.