Age Dependence of Pulse Transit Time Derived from dual PPGs and PPG-ECG duo ‐ A comparative Study

Conventionally, PTT is measured as the time difference between ECG R-peak and PPG peak. However, recent years of research has established a new PTT measurement scheme utilizing two PPG signals acquired from adjacent locations of an unbranched arterial segment. Most often, as people age, their arteries lose elasticity. As a result, the arterial stiffness increases leading to a subsequent decrease in the pulse wave velocity (PWV) and increase in PTT. The work reported herein derives PTT using aforementioned methods and correlates them with age to determine which among the two can most effectively quantify age related variations in arterial elasticity. ECG and two PPG signals were acquired from 20 subjects (11 females, 9 males, age: 31.4 ±6.65). PTT measured using dual PPGs showed a better correlation (Pearson's r=0.6) with age in comparison to the conventional scheme (Pearson's r=0.04). This clearly indicates that PTT measurement using dual PPGs would serve better in estimating age related variations in arterial elasticity than the conventional method.