REFLECTED WAVE PARAMETER ESTIMATION AND AUGMENTATION INDEX CALCULATION FROM PHOTOPLETHYSMOGRAPHY MODEL FOR DIFFERENT AGE GROUPS

Abstract

The reflected wave of Photoplethysmography (PPG) is generated due to impedance mismatch, when the pulse wave propagates along the arterial branches. The objective of the study is to estimate the reflected wave amplitude and duration from PPG and to determine whether it changes with age. Reflected wave of PPG was modeled using the lognormal model fitting method. The duration and amplitude of reflected wave and augmentation index from modeled PPG was compared with the Slope Sum Function (SSF) and second derivative of PPG. PPG was collected from 120 subjects with age [Formula: see text]40 and [Formula: see text]40 years old for carrying out this experiment. Reflected wave duration from modeled PPG and SSF method shows a mean square error value of [Formula: see text] and [Formula: see text] for subjects [Formula: see text]40 and [Formula: see text]40 years age, respectively. The amplitude of reflected wave from PPG model and Second Derivative of Photolethysmography (SDPPG) results in a mean square error of [Formula: see text] and [Formula: see text] for subjects [Formula: see text]40 and [Formula: see text]40 years age, respectively. Augmentation index calculated from PPG model and SDPPG was similar with good level of agreement in the scatter plot. The modeled PPG helps to identify the reflected wave parameter noninvasively and the results show a considerable variation in these parameters with age.