Information Retrieval from Photoplethysmographic Sensors: A Comprehensive Comparison of Practical Interpolation and Breath-Extraction Techniques at Different Sampling Rates

The increasingly widespread diffusion of wearable devices makes possible the continuous monitoring of vital signs, such as heart rate (HR), heart rate variability (HRV), and breath signal. However, these devices usually do not record the “gold-standard” signals, namely the electrocardiography (ECG) and respiratory activity, but a single photoplethysmographic (PPG) signal, which can be exploited to estimate HR and respiratory activity. In addition, these devices employ low sampling rates to limit power consumption. Hence, proper methods should be adopted to compensate for the resulting increased discretization error, while diverse breath-extraction algorithms may be differently sensitive to PPG sampling rate. Here, we assessed the efficacy of parabola interpolation, cubic-spline, and linear regression methods to improve the accuracy of the inter-beat intervals (IBIs) extracted from PPG sampled at decreasing rates from 64 to 8 Hz. PPG-derived IBIs and HRV indices were compared with those extracted from a standard ECG. In addition, breath signals extracted from PPG using three different techniques were compared with the gold-standard signal from a thoracic belt. Signals were recorded from eight healthy volunteers during an experimental protocol comprising sitting and standing postures and a controlled respiration task. Parabola and cubic-spline interpolation significantly increased IBIs accuracy at 32, 16, and 8 Hz sampling rates. Concerning breath signal extraction, the method holding higher accuracy was based on PPG bandpass filtering. Our results support the efficacy of parabola and spline interpolations to improve the accuracy of the IBIs obtained from low-sampling rate PPG signals, and also indicate a robust method for breath signal extraction

Exploration of Web-Sites Affects Autonomic Responses Related to Unconscious Emotions

In this work we are interested in analyzing any correlations between physiological parameters, extracted from signals such as Electrocardiogram, respiratory signal and Skin Conductance, and self-reported indices related to emotional or cognitive stimulations. For this purpose, an experiment involving twenty participants with a mean age of 25±5 years of both sexes (13 males and 7 females) was carried out. The protocol included the navigation in simulated web-sites and the vision of two different commercial products (utilitarian and hedonistic). At the end of the navigation, a questionnaire was submitted to the subject in order to measure his/her feelings and emotions in a qualitative and subjective way. Quantitative features were extracted from the physiological signals recorded during the execution of the protocol. We performed a correlation analysis between self-reported and physiological responses related to Arousal, Pleasure, Expectancy and Situational Involvement. Findings showed that when a consumer is exposed to a utilitarian product, the physiological emotional responses are disassociated from the self-reported ones. For the hedonistic product, instead, self-reported measures significantly correlate with physiological arousal features like the combined effect of cardiac and respiratory activity and the Heart Rate

Signal processing for cardiovascular applications in p-health

New portable and wearable devices as well as networking technologies make possible new home monitoring and p-health solutions. A key element is the information extraction process, which is required for the correct interpretation of the data focused on specific pathologies and applications. This chapter presents a review of the main steps for data preprocessing and for feature extraction in the time, frequency, and information domains. For cardiovascular applications the signal that is usually considered is the electrocardiogram, from which cardiac cycles are detected for further analysis. In particular, the heart rate variability signal is extracted, which provides useful parameters for monitoring of the cardiovascular system. These parameters can be obtained also from photoplethysmograms and ballistocardiograms, which are easily recorded through wearable devices. However, the different natures of the signals and their different time resolutions, as well as nonstationarity due to the ambulatory condition of the users, may lead to a degradation of the extracted information. This chapter also discusses the effects of reduced sampling frequency and suggests strategies for managing nonstationary conditions. Some examples are shown, which are mainly related to sleep analysis

Bictegravir/Emtricitabine/Tenofovir Alafenamide Treatment: Efficacy and Tolerability in Clinical Practice

Diana Canetti,1 Laura Galli,1 Riccardo Lolatto,1 Silvia Nozza,2 Vincenzo Spagnuolo,1 Camilla Muccini,1 Benedetta Trentacapilli,2 Elena Bruzzesi,2 Martina Ranzenigo,2 Matteo Chiurlo,2 Antonella Castagna,1,2 Nicola Gianotti1 1Infectious Diseases Unit, San Raffaele Scientific Institute, Milan, Italy; 2Infectious Diseases Unit, Vita Salute San Raffaele University, Milan, ItalyCorrespondence: Diana Canetti, Infectious Diseases Unit San Raffaele Scientific Institute, Via Stamira D’Ancona 20, Milano, 20127, Italy, Tel +390226432461, Fax +390226437943, Email [email protected]: Analysis of bictegravir/emtricitabine/tenofovir alafenamide (BFTAF) efficacy and safety in virologically suppressed people living with HIV (PLWH) in clinical practice.Patients and methods: The retrospective cohort study, which included adult treatment-experienced and virologically suppressed PLWH, switched to BFTAF from June 2019 to June 2021. Efficacy and safety were evaluated as virological failure (VF=2 consecutive HIV-RNA> 50 copies/mL or a single HIV-RNA> 400 copies/mL) and treatment failure (TF=VF or discontinuation for any reason) until data freezing (August 2022).Results: Of the 1040 PLWH included, 67.8% switched from elvitegravir/cobicistat/FTAF. VF occurred in 4.2% (n=44), with incidence rate of 1.63 per 1000 person-months of follow-up (PMFU) and probability at 24– 30 months of 3.8%– 4.0%, respectively. Out of the 44 VF, in 75% virological re-suppression was achieved while maintaining BFTAF. Discontinuation occurred in 15% after a median time of 13.5 months of follow-up, with an incidence rate of 5.67 per 1000 PMFU, and a probability at 24– 30 months of 11.9%– 15.3%, respectively. Main discontinuation reasons were simplification (51.3%) and toxicity (21.8%, involving CNS in half of cases). TF occurred in 18.6% with an incidence rate of 7.01 per 1000 PMFU after a median time of 13.6 observation months; probability at 24– 30 months was 14.8%– 18.4%, respectively.Conclusion: BFTAF has proven effective and well tolerated in clinical practice.Plain Language Summary: In Clinical Randomized Trials, BFTAF proved to have a high genetic barrier regimen.In this context of clinical practice:BFTAF proved effective and well toleratedIt showed a low rate of virological failureDiscontinuation was largely influenced by simplification with 2-drug regimens.Keywords: bictegravir, people living with HIV, PLWH, efficacy, safety, clinical practic