[p1] Applications in various physical and biological systems


Chaotic characteristics of green light photoplethysmogram

N. Sviridova (Meiji University)


The photoplethysmogram (PPG) is signal produced by the cardiovascular system that has been widely used in medical and sports equipment for assessment of the heart rate and oxygen saturation. Traditionally near infrared light (NIR) was utilized in the PPG recorders, however, recent studies demonstrated that green light based devices can provide better results. Methods of nonlinear time series analysis has previously demonstrated high potential for utilization in various applications for physiological and mental health monitoring by NIR PPG. However, as green light has different penetration depth into the skin compared with NIR PPG, its dynamics and, therefore, its chaotic characteristics obtained by nonlinear time series analysis are expected to be different. This study sought to investigate chaotic characteristics of green light PPG and find out whether there are considerable differences with characteristics corresponding to NIR PPG. As subject age has significant influence on the PPG parameters, in this study additional attention was paid to the variation of green light PPG chaotic characteristics among different age groups. Results demonstrated that methods of nonlinear time series analysis can be efficiently applied to green light PPG for obtaining its chaotic characteristics. Additionally, considerable variation of characteristics values among different age groups was found.