doi:10.1088/1361-6579/ab009bengPeralta Calvo, ElenaLázaro Plaza, JesúsBailón Luesma, RaquelMarozas, VaidotasGil Herrando, EduardoOptimal fiducial points for pulse rate variability analysis from forehead and finger PPG signalsART-2019-109892Objective: The aim of this work is to evaluate and compare five fiducialpoints for the temporal location of each pulse wave from forehead and fingerphotoplethysmographic pulse waves signals (PPG) to perform pulse rate variability(PRV) analysis as a surrogate of heart rate variability (HRV) analysis. Approach: Forehead and finger PPG signals were recorded during tilt-table testsimultaneously to the ECG. Artifacts were detected and removed and, five fiducialpoints were computed: apex, middle-amplitude and foot points of the PPG signal,apex point of the first derivative signal and, the intersection point of the tangent tothe PPG waveform at the apex of the derivative PPG signal and the tangent to thefoot of the PPG pulse defined as intersecting tangents method. Pulse period (PP)time intervals series were obtained from both PPG signals and compared to the RRintervals obtained from the ECG. Heart and pulse rate variability signals (HRV andPRV) were estimated and, classical time and frequency domain indices were computed. Main Results: The middle-amplitude point of the PPG signal (nM), the apexpoint of the first derivative (n*A), and the tangents intersection point (nT) are themost suitable fiducial points for PRV analysis, which result in the lowest relativeerrors estimated between PRV and HRV indices, higher correlation coefficients and reliability indexes. Statistically significant differences according to the Wilcoxon testbetween PRV and HRV signals were found for the apex and foot fiducial points ofthe PPG, as well as the lowest agreement between RR and PP series according toBland-Altman analysis. Hence, they have been considered less accurate for variabilityanalysis. In addition, the relative errors are significantly lower fornMandn*Afeaturesby using Friedman statistics with Bonferroni multiple-comparison test and, we proposenMas the most accurate fiducial point. Based on our results, forehead PPG seems toprovide more reliable information for a PRV assessment than finger PPG. Significance: The accuracy of the pulse wave detections depends on the morphologyof the PPG. There is therefore a need to widely define the most accurate fiducial pointto perform a PRV analysis under non-stationary conditions based on different PPGsensor locations and signal acquisition techniques.2019http://zaguan.unizar.es/record/8651210.1088/1361-6579/ab009bhttp://zaguan.unizar.es/record/86512oai:zaguan.unizar.es:86512info:eu-repo/grantAgreement/ES/UZ/UZ2018-TEC-05This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 745755-WECARMONinfo:eu-repo/grantAgreement/EC/H2020/745755/EU/Wearable Cardiorespiratory Monitor/WECARMONinfo:eu-repo/grantAgreement/ES/DGA-FEDER/T39-17R-BSICoSPHYSIOLOGICAL MEASUREMENT 40, 2 (2019), 025007 [15 pp.]by-nc-ndhttp://creativecommons.org/licenses/by-nc-nd/3.0/es/info:eu-repo/semantics/openAccess