IEEE Trans Acoust 1981, 29: 654659. J Clin Monit Comput. Modulation of muscle sympathetic activity during spontaneous and artificial ventilation and apnoea in humans. The AR modeling procedure means to find the optimal model coefficients k These techniques may involve end-tidal CO2 monitoring, nasal thermistances, respiratory inductance plethysmography via chest bands and ECG-based electrical impedance. 1 As mentioned earlier, after repeating this calculation for our data, we obtained the same value for standard deviation with a slightly lower mean value. 0000003559 00000 n Respiratory rate is subject to change and may be an important vital sign to monitor. (k) is calculated as follows: As a result, the ALNF traces the biased frequency. Respiration Rate. Bergese SD, Mestek ML, Kelley SD, et al. Multicenter study validating accuracy of a continuous respiratory rate measurement derived from pulse oximetry: a comparison with capnography. RR According to our results, PPG-RR is an interesting approach for ventilation monitoring, as this technique would make simultaneous monitoring of respiratory rate and arterial oxygen saturation possible, thus minimizing the number of sensors attached to the patient. P-values of paired t-test for MIT open source data and Wilcoxon signed rank test for measured data are less than 0.0001. By adding x in Eq. 3 depicts a MATLAB generated plot using the publicly available BIDMC dataset. 0000341776 00000 n The PPG is considered to be very sensitive to any irregularity of the pulse [33]. 0000342886 00000 n 0000140877 00000 n Terms and Conditions, I want to find out respiration rate for the infants and adults. Mochizuki K, Shintani R, Mori K, Sato T, Sakaguchi O, Takeshige K, Nitta K, Imamura H. Importance of respiratory rate for the prediction of clinical deterioration after emergency department discharge: a single-center, case-control study. The respiratory synchronous variation POP (%) = 100 ([POPmax POPmin]/[(POPmax + POPmin)/2]) can be recorded from a commercial pulse oximeter attached to a finger, if the automatic gain is disabled or held constant to allow RIIV at the baseline to emerge.43 POP is strongly related to the respiratory variation in pulse pressure, PP.44 PP is calculated over a respiratory cycle in the same way as POP. As in Eq. Although many researchers have achieved a technical progress to monitor the cardiopulmonary system [1, 16, 17], mobility and fast processing remain as challenges [15]. 2003;41:37783. The size of the PPG respiration variation can predict fluid responsiveness in mechanically ventilated patients. Aust J Basic Appl Sci 2012, 6: 337352. Respiration Rate from the Pleth (RRp). In addition to variations in light modulation by the cardiac cycle, the PPG signal contains a respiratory modulation and variations associated with changing tissue blood volume of other origins. Park, C., Lee, B. Real-time estimation of respiratory rate from a photoplethysmogram using an adaptive lattice notch filter. 0000044228 00000 n Med Biol Eng Comput. 538891. Karlen W, Raman S, Ansermino JM, Dumont GA: Multiparameter respiratory rate estimation from the photoplethysmogram. Monitoring the cardiorespiratory activities via the PPG signal is a well established noninvasive technique. Cretikos MA, Bellomo R, Hillman K, Chen J, Finfer S, Flabouris A. Lee J, Chon KH: Time-varying autoregressive model-based multiple modes particle filtering algorithm for respiratory rate extraction from pulse oximeter. The baselines move up and down in an oscillatory pattern corresponding to the breath cycle. Predicting fluid responsiveness is also of importance in nonanesthetized patients. corresponds to the pole and zero contraction factor. Identifying airway obstructions using photoplethysmography (PPG). All recordings from the ReaSTOC database were prospectively performed by the same research assistant, using a standardized protocol. Given Taken together, the ALRE might be considerably better than Burgs method in real-life and real-time applications. It is based on the optical technique photoplethysmography (PPG). Furthermore, we designed a sequential infinite impulse response (IIR) notch filtering system (i.e., harmonic IIR notch filter) to eliminate the cardiac component and its harmonics from the PPG. j Accepted for publication November 16, 2012. Advanced statistical signal processing techniques were used to enhance these components and thus reduce the effect of unavoidable disturbance such as artefacts or transient and spontaneous phenomena. Let us consider a second-order AR modeling problem. 0000109239 00000 n 1940;4:3319, 5. k Physiologic variations such as vasoconstriction, a deep gasp, or yawn also affect the signal. (n), we constructed the simulated PPG signal x(n), and its shape was similar to the real PPG (see Figure7). PubMed Springer Nature. Partridge BL. Chon KH, Dash S, Ju K: Estimation of respiratory rate from photoplethysmogram data using time-frequency spectral estimation. Johansson A, Oberg PA. Estimation of respiratory volumes from the photoplethysmographic signal. [35] compared the respiratory rate estimated by manual counting with that obtained using electrical impedance, with chest electrodes. Irregular fluctuations of low amplitude can be observed in the peripheral venous pressure and RIIV signals during apnea.18 Also, slower arterial pressure waves persist during apnea.34 During apnea without respiratory movements, the respiratory rhythm of the sympathetic nerve activity seems to persist, influencing the vascular system at a periodicity of 0.1 Hz.34 In spectral analysis during apnea, low frequency content is present in arterial blood pressure and in sympathetic nerve activity.35 Low frequency autonomic rhythms are also unaffected by differences in respiratory rate.35 The detection of central apnea is scarcely evaluated and more studies in the clinical setting are warranted. Clin Sci. As a result, the AR modeling method has an inefficient computational structure in real-time applications, and the estimate of the AR method lags behind the true RR varying with time. D Respiration causes blood volume variations on both the arterial and venous sides. Physiologic variations such as vasoconstriction, coughing, a deep gasp, or yawn also affect the PPG signal. Both authors read and approved the final manuscript. Physiol Meas. Ann Biomed Eng. Haba-Rubio J, Darbellay G, Herrmann FR, Frey JG, Fernandes A, Vesin JM, Thiran JP, Tschopp JM. Most of all, the vast majority of these algorithms have not been implemented in any medical devices for a routine clinical validation, except one [21]. From this assumption, we can model a PPG by adding cardiac and respiratory components as follows: where the first term represents the cardiac component and the second term does the respiratory component. Vol. Spectrum estimators can be classified into two categories, the parametric method and the non-parametric method; their characteristics are explained in [20]. The principle of the PPG technique is simple. Dornhorst AC, Howard P, Leathart GL. Acta Anaesthesiol Scand. The author declares no conflicts of interest. Keller et al.59 showed that a threshold PVI value of >19% was a weak predictor of response to passive leg raising in spontaneously breathing volunteers. There is, however, a risk that autonomic nerve activity can influence the PPG signal and interfere with the reading. Your message has been successfully sent to your colleague. It is an adaptive notch filer combined with a lattice form for an adaptation algorithm. 2007;106:110511, 44. Anesthesiology. In all phases, reference RR was measured continuously using both electrical thoracic impedance (ECG-RR) and chronometric evaluation (Manual-RR) over a 30-s period, under spontaneous ventilation or ventilatory rate (Ventilator-RR) for patients under ventilatory assistance. 1996;18:36572. Qualitative RIIV signals may be used for monitoring purposes regardless of age, gender, anesthesia, and mode of ventilation. The aim of the Respiratory Rate Estimation project is to develop and assess methods for automated respiratory rate (RR) monitoring. Cannesson M, Desebbe O, Rosamel P, Delannoy B, Robin J, Bastien O, Lehot JJ. 2011;55:68693, 55. 1. Continuous calculations were performed each respiratory cycle, within a 10-min moving average window. A Bland-Altman plot showed an agreement between the IRR obtained from PPG and reference respiratory rate with a bias of -0.32 and limits agreement of -7.72 to 7.07. Anesth Analg. Firstly, the proposed method used a direct way to measure respiratory rate, unlike methods of PPG or ECG, hence, may require fewer computational steps with direct processing of respiratory rates on sensor. Acta Anaesthesiol Scand. 2 Photoplethysmographic determination of the respiratory rate in acutely ill patients: validation of a new algorithm and implementation into a biomedical device, https://doi.org/10.1186/s13613-019-0485-z, https://www.ersnet.org/pdf/publications/firs-world-report.pdf, http://creativecommons.org/licenses/by/4.0/. + means j-th forward prediction error and e If we invert the transfer function of this AR model, then we can obtain a notch filter and estimate the frequency from a pair of zeroes of the notch filter. Br J Anaesth. 1981;19:26770, 29. In Figure11, the dotted line represents the reference RR, which was acquired from the respiratory signal, and the solid lines correspond to the RR and HR estimates. In Figure3, k Among sensors for biosignals, the use of PPG-based systems is widespread and it appears in clinical applications like obstructive sleep apnea detection in children [ 4] and respiration influence on arterial pressure etc. Available alongside clinically proven Masimo SET pulse oximetry, RRp allows clinicians to seamlessly implement respiration rate monitoring without additional equipment. s The first limit of the study that may be considered is the fact that a contrario to other validation studies for different RR measurement devices and/or algorithms, we chose to compare mean RR values over a clinically relevant period, instead of comparing peak-by-peak values. 0000010817 00000 n Because of the development of sensing and communication techniques, the healthcare industry has made much progress in recent years; to further enhance this progress, mobility and fast processing are increasingly in demand [15]. 1869;60:82956, 10. Future studies could explore this field.46. Madisetti V: Digital Signal Processing Handbook. 1993;460:64155, 13. The agreement between quantitative measure of the reference and the estimated RR values (PPG-RR) was then graphically appreciated according to Bland and Altman [27]. j Although a previous study [8] showed that it is possible to reduce the cardiac component and enhance the respiratory component by using an IIR low-pass filter, some portion of the cardiac component remain in the respiratory component because the IIR low-pass filter is limited to eliminating the cardiac component whose frequencies are above the cut-off frequency. In conclusion, the novelty of the ALRE stands out because of its simple structure and fast processing without constrained ranges of HR or RR estimate. Respiratory-induced intensity variations (RIIVs) contained in the baseline of the PPG signal have been well documented (Fig. Because of low scattering and absorption, there is an optical window in skin and most other soft tissues in the region of 600 to 1300 nm. Artifacts caused by movement of the probe against the skin were identified in the 1930s and led to the development of positioning devices. Detection of breaths in adult volunteers had a maximal error of 8%. corresponds to the first derivative of (n) which is an operand of the cosine function of x The peripheral pulse wave: information overlooked. By using this website, you agree to our hV}PSW?/yyILC#@`YRY vFS}`qjZg@aM|UjfX]Vvw{ %<4%A 0000001696 00000 n Technology, Computing, and Simulation: Special Article, Frequency Bands in the Photoplethysmographic Signal. 0000340137 00000 n Pulse oximetry is based on the technique of photoplethysmography (PPG) wherein light transmitted through tissues is modulated by the pulse. 2005;49:115762, 24. ELH and FL are co-inventors and funded the company (Oxynov) that develops the FreeO2 system; ELH has received honorarium for consultancy from Smiths Medical, General Electrics Healthcare, Sedana, Oxynov and Air Liquide Medical Systems; FL has received research funding from Fisher Paykel and Hamilton Medical and received honorarium for consultancy from Oxynov; QTN was originally the PhD student that developed the algorithm and is now employee of Oxynov Inc. VP was financed by a research grant from Oxynov Inc. as a research assistant. When asymptotically reaches 1, the frequency response goes to the notch, and the gain of the center frequency approximately becomes 0. The AR model is one of many signal modeling techniques, and is composed only of autoregressive and error terms, as follows: where x(n) is the target signal and e(n) represents the residual error. Makhoul J, Cosell L: Adaptive lattice analysis of speech. IEEE Trans Circuits Syst II Analog Digit Signal Process 1993, 40: 405416. Nilsson L, Johansson A, Kalman S. Macrocirculation is not the sole determinant of respiratory induced variations in the reflection mode photoplethysmographic signal. j+1 is determined by a combination of the j th order forward prediction error e , as follows: All-pole lattice filter for Burgs method. Comparison of the methods using the BlandAltman method depicted a low bias (0.5c/min) and acceptable deviation (<5.5c/min). Critical review of non-invasive respiratory monitoring in medical care. [23]: Furthermore, will be approximately 0 but not equal to 0. : Thus, ALNF has three parameters: (pole and zero contraction factor), (smoothing factor), and (forgetting factor). Volume: 1 Issue: 2 2.1 Respiration Exchange of gases in humans is commonly termed as respiration. J Biomed Eng 1993, 15: 151154. 2000;278:H125660, 14. n Improvements in neural network technology together with combining the respiratory rate and the arterial saturation monitoring might increase sensitivity and specificity for detecting both central and obstructive apnea. Hertzman AB, Spealman CR. Hagbarth KE, Vallbo AB. From these needs, we attempted to develop a method to estimate RR from a PPG with a light computational burden. Therefore, we set sufficiently close to 1. By analyzing the PPG signal, the information of the cardiorespiratory activities such as both the heart rate and the respiratory rate could be estimated. 2014;113:1957. A pair of poles of this model is directly linked to a pair of peaks of spectrum, which represents one dominant frequency. j Privacy Features based on frequency domain analysis, morphology-based analysis are used for the fusion process. Biais M, Cottenceau V, Petit L, Masson F, Cochard JF, Sztark F. Impact of norepinephrine on the relationship between pleth variability index and pulse pressure variations in ICU adult patients. 1985;57:52430, 40. In this paper, an algorithm for breathing rate extraction from PPG signal is proposed. This algorithm is constructed by simple methods that feature light computation and on-line processing to obtain real-time filtering. 0000015956 00000 n IEEE Signal Process Mag 2009, 26: 186189. 2007;21:5561. Autet LM, Frasca D, Pinsard M, et al. However, unlike the AR modeling method, the adaptive notch filers order is essentially fixed at 2, and it estimates only a single dominant frequency. This method is only reliable in cases of spontaneous ventilation and in individuals with sinus cardiac rhythm. 10.1093/bja/57.5.524, Addison PS, Watson JN, Mestek ML, Mecca RS: Developing an algorithm for pulse oximetry derived respiratory rate (RR(oxi)): a healthy volunteer study. 10.1161/01.CIR.101.23.e215. This approach has several inherent limitations that diminish the clinical utility of these measurements mainly because it is intermittent, and some patients morphology (e.g. It fluctuates slowly because of varying venous capacity. RRp is one of three proprietary respiration rate monitoring options available to support clinicians in a variety of clinical scenarios: For professional use. 2008;101:2006, 48. From the presence of the respiratory response in a PPG, many researchers have been motivated to develop or utilize methods for RR estimation from a PPG, such as digital filters, the autoregressive (AR) model, variable frequency complex demodulation, and particle filters [2, 814]. 1, the phases ( In this study, we used the AC signal component of a PPG to estimate the respiratory rate. 0000109367 00000 n were recorded by the research assistants using our standard monitoring devices and the computerized medical file (ICCA Philips Healthcare, Amsterdam, the Netherlands). Hayes MH: Statistical Digital Signal Processing and Modeling. J Clin Monit Comput. (17). Power spectral analysis of heart rate variability: a noninvasive signature of cardiac autonomic function. Anesthesiology. PPG was described in 1937 to measure blood volume changes. The venous distensibility is increased when the pressure in the veins is decreased, and the amplitude of RIIV is accordingly enlarged.39, The arterial pressure waveform changes with hypovolemia. Measurement of respiratory rate from the photoplethysmogram in chest clinic patients. resp An algorithm for the detection of individual breaths from the pulse oximeter waveform. Attestation: Lena Nilsson approved the final manuscript. 1997;86:1018, 7. cardiac The RIIV in the baseline of the PPG signal is sensitive to hypovolemia.26 The RIIV amplitude depends on the ventilatory changes in central venous pressure that are transmitted to the peripheral venous pressure. min 1937;119:3345, 4. As mentioned before, the robustness to colored noise was enhanced as increased. resp Dashed red box includes only RR estimation results for the ALRE and Burgs method. This method showed outstanding accuracy, but its computational burden was not sufficiently light to construct a real-time monitoring system [5, 14]. 2007;46:17549, 3. This method is only reliable in cases of spontaneous ventilation and in individuals with sinus cardiac rhythm. The RIIV and the pulse synchronous PPG waveform are sensitive for detecting hypovolemia. https://doi.org/10.1186/s13613-019-0485-z, DOI: https://doi.org/10.1186/s13613-019-0485-z. During central apnea, the rhythmic RIIV signals caused by variations in intrathoracic pressure disappear. Med Eng Phys. Values from 9.5%48 to 14%47,52 have been reported from patients under anesthesia and a threshold value of 17%51 was found in deeply sedated patients in intensive care. 2011;66:5829, 51. Photoplethysmography: beyond the calculation of arterial oxygen saturation and heart rate. Physiol Meas. The range for rate is 0 to 60. The transmural right chamber pressure varies by 32%, whereas the mean arterial blood pressure in the carotid artery only varies by 2%.11 The largest blood volume is found on the venous side of the circulatory system, and because this is a low pressure system, it is sensitive to small variations in pressure. California Privacy Statement, For example, pulmonary or cardiovascular diseases can be detected by measuring RR [7]. 2010;111:9104, 53. PPG-RR determination was available in 95.5% cases (Table2). 0000012278 00000 n For example, RR should be less than 0.6Hz [8]. 164 - 184 hemoglobin molecule is. ALRE estimated RR accurately and it was very close to the reference RR as in the middle column of Figure11 in contrast to Burgs method (right column of Figure11). Although the ALRE has several advantages, it still should be improved to be embedded in mobile devices because of the problem of convergence time. Thus, unlike the AR method, it does not restrict the estimated HR or RR ranges but uses only the feasible ranges (HR: 0.5~5Hz, RR: 0.1~2Hz). Li J, Jin J, Chen X, Sun W, Guo P. Comparison of respiratory-induced variations in photoplethysmographic signals. 10.1016/1350-4533(95)00066-6. RR tracking from simulated PPG. 0000017210 00000 n To analyze the baseline modulation, we consider a two-tone signal x (n) with additive white Gaussian noise v (n): where As breathing movements disappear during central apnea, the phasic PPG respiratory signal vanishes. Eqs. The baselines move up and down in an oscillatory pattern, which corresponds to the breath cycle. By using the beat-to-beat respiratory fluctuations in pulse transit time, almost 90% of the breaths can be detected during spontaneous breathing.32, To decrease the error rate of detecting respiratory rhythms, a combination of detection principles can be used. Nilsson et al. Solid lines represent estimates and dotted lines are reference values when all input signals SNRs are 10dB. Ann. Pulse oximetry. The MAX30101 PPG Sensor.The MAX30101 sensor is produced by Maxim Integrated and is designed in biomedical applications for the detection of heart rate and blood oxygen saturation. 1992;30:5337, 22. Cannesson M, Besnard C, Durand PG, Boh J, Jacques D. Relation between respiratory variations in pulse oximetry plethysmographic waveform amplitude and arterial pulse pressure in ventilated patients. Pleth variability index to predict fluid responsiveness in colorectal surgery. 2013;51:96570. PPG-RR determination was available in 95.5% cases, similar to reference (224 vs. 225c/min, respectively; p=1), and well correlated with reference values (R=0.952; p<0.0001), with a low bias (0.1b/min) and deviation (3.5b/min). When the model order is M, the coefficient k Cheng M-H, Tsai J-L: A new IIR adaptive notch filter. 2008;12:R37, 60. Respiratory variations in pulse oximetry plethysmographic waveform amplitude to predict fluid responsiveness in the operating room. The first step is the estimation of HR using a frequency estimator (ALNF) which traces the fundamental frequency of a harmonic signal. Spectral analysis techniques can be used to characterize oscillations by dividing them into their sinusoidal components. (center frequency of D(ej)) approaches nearby Obstructive apnea can be traced by PPG with a sensitivity of 75% and a specificity of 85%. Because autoregressive modeling requires batch processing, they used a moving-window method for the real-time process [10]. Low- and intermediate-frequency vasomotor waves might interfere with respiratory waves. The need to design a comfortable, portable, and fast-processing system has grown stronger as ubiquitous healthcare industry has grown [15]. 2005;26:104958. 2006;20:4316, 25. Although both are accurate predictors of fluid responsiveness,43 the threshold values for discrimination between fluid responders and nonresponders are not numerically identical between PP and POP. Vertical axis unit of left-side is dB and that of right-side is absolute value. Schoonjans A, Forget P, Labriola L, Deneys V, Jadoul M, Pingaut I, De Kock M. Pleth variability index combined with passive leg raising-induced pulse pressure variation to detect hypovolemia in spontaneously breathing patients. s CP designed the algorithm, collected the data, analyzed and interpreted data, and drafted the manuscript. (a) and (b) represent PPG and the reference respiratory signal from MIT MIMIC data, respectively. Erwan LHer. This is due to the greater buffering capacity of the right heart chamber and of the pulmonary circulation. 1 Respiratory rate, tidal volume & respiratory minute volume Both respiratory rate and tidal volume depend on age and body size. The AC and DC components are used similarly, with an automated function, pleth variability index (PVI), commercialized in 2007. IEEE Trans Biomed Eng 2010, 57: 10991107. Folke M, Cernerud L, Ekstrm M, Hk B. Those authors used a noncommercial reflection mode probe placed on the thigh. 2012;12:223654, 47. Anesth Analg. 1987;3:2638, 42. J Clin Monit Comput. The units form mathematical algorithms. Longer wavelengths penetrate deeper into the tissue and collect information from different blood vessels than shorter wavelengths. Impact of skin incision on the pleth variability index. However, smaller parameter values result in worse performance. Pleth variability index is a continuous measure of the respiratory modulation of the pulse oximeter waveform and has been shown to predict fluid responsiveness in mechanically ventilated patients including infants. 1). Chronometric measurements of the respiratory rate (Manual-RR), electrical thoracic impedance (ECG-RR) and ventilatory respiratory rate values (Ventilator-RR) were regarded as the reference methods for respiration rate assessment and plethysmographic calculations (PPG-RR) as the method of comparison. Linear correlation between the different methods was performed using Pearsons correlation coefficient analysis; Intraclass correlation coefficient (ICC) for average measurements is presented as a single-number summary that was used to assess reliability of different measurements averaged together [26]. 10.1007/s10439-010-0080-9. 2010;61:14750. During the prospective evaluation phase, PPG-RR calculations were performed using PPG signals extracted from the Nonin PureSAT internal OEM III (Plymouth, MN, USA) of the FreeO2 system (Oxynov Inc., Qubec, QC, Canada), using a standard reusable Nonin PureLight finger clip sensor, positioned on the index, middle or ring finger. Springer Nature. Leonard P, Grubb NR, Addison PS, Clifton D, Watson JN. Despite these advantages, its estimate can be biased when the colored noise is added to the input signals. Artificial neural networks are extensively used in electronic signal analysis, including PPG. Illumination was another issue, because the early light sources gave light with a wide spectrum without constant intensity. Respiratory rate extraction from pulse oximeter and electrocardiographic recordings. 2007;25:63742, 46. Wertheim et al.31 reliably monitored respiratory rate from pleth data from a commercially available pulse oximeter during natural quiet sleep. matlabalgorithmrespirationfromecg 4/7 Downloaded from start.nucleoexpert.com on by guest title matlab algorithm respiration from ecg author 128 199 203 98 2022 09 03 . Crit Care. Left two columns means RMSEs (the ALREs and Burgs methods) from MIT MIMIC data, and right two columns represent RMSEs (the ALREs and Burgs methods) from experiment data measured by BIOPAC device. (n) and x ^ (2016) for further details): 1) Identifying individual pulse waves. During the prospective phase, PPG-RR calculations were automatically and continuously performed using a dedicated device (FreeO2, Oxynov, Qubec, QC, Canada). Correspondence to By minimizing E[y2(n)], we can get the value of the adaptation parameter k 2001;280:H267488, 36. Our local ethics committee (Comit dEthique du CHRU de Brest) approved the data collection study and waived written informed consent according to French legislation. In this work, a novel end-to-end deep learning network called RespNet is proposed to perform the task of extracting the respiration signal from a given input PPG as opposed to extracting respiration rate. The respiratory components acquired after harmonic IIR notch filtering are presented in Figure9 (c) and (f). Cbl Med Wiss. 1999;37:4853, 18. An End-to-End and Accurate PPG-based Respiratory Rate Estimation Approach Using Cycle Generative Adversarial Networks 12 0 0.0 ( 0 ) . The open-source data was adopted from the MIT MIMIC Database, which has been used in previous studies [28]. Olsson E, Ugnell H, Oberg PA, Sedin G. Photoplethysmography for simultaneous recording of heart and respiratory rates in newborn infants. Clinical metadata (physiological parameters, clinical status, underlying pathology, medications, etc.) Aoyagi T, Kishi M, Yamaguchi K, Nakajima S, Hirai H, Takase H, Kuse A. (0) and R See instructions for use for full prescribing information including indications, contraindications, warnings and precautions. To compare the two methods, we performed statistical tests on the MIT open-source data by using a paired t-test and on our measured data with non-parametric Wilcoxons two-sampled signed rank test under calculated RMSEs; the p-values of both tests were less than 0.0001. In addition, it can measure other physiological information such as pulse rate (or heart rate) and respiratory rate (RR) by one wearable sensor unlike electrocardiography [1]. Artificial neural networks help to detect complex nonlinear relationships and are extensively used in electronic signal analysis, including PPG. As we mentioned earlier, the optimal selection of the AR model order is quite important to estimate a spectrum and frequencies.