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Article ; Online: A smoothed boundary bidomain model for cardiac simulations in anatomically detailed geometries.

Biasi, Niccolò / Seghetti, Paolo / Mercati, Matteo / Tognetti, Alessandro

2023 Volume 18, Issue 6, Page(s) e0286577

Abstract: This manuscript presents a novel finite difference method to solve cardiac bidomain equations in anatomical models of the heart. The proposed method employs a smoothed boundary approach that represents the boundaries between the heart and the surrounding ...

Abstract	This manuscript presents a novel finite difference method to solve cardiac bidomain equations in anatomical models of the heart. The proposed method employs a smoothed boundary approach that represents the boundaries between the heart and the surrounding medium as a spatially diffuse interface of finite thickness. The bidomain boundary conditions are implicitly implemented in the smoothed boundary bidomain equations presented in the manuscript without the need of a structured mesh that explicitly tracks the heart-torso boundaries. We reported some significant examples assessing the method's accuracy using nontrivial test geometries and demonstrating the applicability of the method to complex anatomically detailed human cardiac geometries. In particular, we showed that our approach could be employed to simulate cardiac defibrillation in a human left ventricle comprising fiber architecture. The main advantage of the proposed method is the possibility of implementing bidomain boundary conditions directly on voxel structures, which makes it attractive for three dimensional, patient specific simulations based on medical images. Moreover, given the ease of implementation, we believe that the proposed method could provide an interesting and feasible alternative to finite element methods, and could find application in future cardiac research guiding electrotherapy with computational models.
MeSH term(s)	Humans ; Computer Simulation ; Heart/diagnostic imaging ; Heart Ventricles ; Mathematics ; Models, Cardiovascular ; Algorithms
Language	English
Publishing date	2023-06-09
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2267670-3
ISSN	1932-6203 ; 1932-6203
ISSN (online)	1932-6203
ISSN	1932-6203
DOI	10.1371/journal.pone.0286577
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Article ; Online: A computationally efficient dynamic model of human epicardial tissue.

Biasi, Niccoló / Tognetti, Alessandro

PloS one

2021 Volume 16, Issue 10, Page(s) e0259066

Abstract: We present a new phenomenological model of human ventricular epicardial cells and we test its reentry dynamics. The model is derived from the Rogers-McCulloch formulation of the FitzHugh-Nagumo equations and represents the total ionic current divided ... ...

Abstract	We present a new phenomenological model of human ventricular epicardial cells and we test its reentry dynamics. The model is derived from the Rogers-McCulloch formulation of the FitzHugh-Nagumo equations and represents the total ionic current divided into three contributions corresponding to the excitatory, recovery and transient outward currents. Our model reproduces the main characteristics of human epicardial tissue, including action potential amplitude and morphology, upstroke velocity, and action potential duration and conduction velocity restitution curves. The reentry dynamics is stable, and the dominant period is about 270 ms, which is comparable to clinical values. The proposed model is the first phenomenological model able to accurately resemble human experimental data by using only 3 state variables and 17 parameters. Indeed, it is more computationally efficient than existing models (i.e., almost two times faster than the minimal ventricular model). Beyond the computational efficiency, the low number of parameters facilitates the process of fitting the model to the experimental data.
MeSH term(s)	Action Potentials/physiology ; Computer Simulation ; Heart Conduction System/physiology ; Humans ; Models, Cardiovascular ; Pericardium/physiology ; Ventricular Function/physiology
Language	English
Publishing date	2021-10-26
Publishing country	United States
Document type	Journal Article
ISSN	1932-6203
ISSN (online)	1932-6203
DOI	10.1371/journal.pone.0259066
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Article ; Online: Digital Phenotyping for Monitoring Mental Disorders: Systematic Review.

Bufano, Pasquale / Laurino, Marco / Said, Sara / Tognetti, Alessandro / Menicucci, Danilo

Journal of medical Internet research

2023 Volume 25, Page(s) e46778

Abstract: Background: The COVID-19 pandemic has increased the impact and spread of mental illness and made health services difficult to access; therefore, there is a need for remote, pervasive forms of mental health monitoring. Digital phenotyping is a new ... ...

Abstract	Background: The COVID-19 pandemic has increased the impact and spread of mental illness and made health services difficult to access; therefore, there is a need for remote, pervasive forms of mental health monitoring. Digital phenotyping is a new approach that uses measures extracted from spontaneous interactions with smartphones (eg, screen touches or movements) or other digital devices as markers of mental status. Objective: This review aimed to evaluate the feasibility of using digital phenotyping for predicting relapse or exacerbation of symptoms in patients with mental disorders through a systematic review of the scientific literature. Methods: Our research was carried out using 2 bibliographic databases (PubMed and Scopus) by searching articles published up to January 2023. By following the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines, we started from an initial pool of 1150 scientific papers and screened and extracted a final sample of 29 papers, including studies concerning clinical populations in the field of mental health, which were aimed at predicting relapse or exacerbation of symptoms. The systematic review has been registered on the web registry Open Science Framework. Results: We divided the results into 4 groups according to mental disorder: schizophrenia (9/29, 31%), mood disorders (15/29, 52%), anxiety disorders (4/29, 14%), and substance use disorder (1/29, 3%). The results for the first 3 groups showed that several features (ie, mobility, location, phone use, call log, heart rate, sleep, head movements, facial and vocal characteristics, sociability, social rhythms, conversations, number of steps, screen on or screen off status, SMS text message logs, peripheral skin temperature, electrodermal activity, light exposure, and physical activity), extracted from data collected via the smartphone and wearable wristbands, can be used to create digital phenotypes that could support gold-standard assessment and could be used to predict relapse or symptom exacerbations. Conclusions: Thus, as the data were consistent for almost all the mental disorders considered (mood disorders, anxiety disorders, and schizophrenia), the feasibility of this approach was confirmed. In the future, a new model of health care management using digital devices should be integrated with the digital phenotyping approach and tailored mobile interventions (managing crises during relapse or exacerbation).
MeSH term(s)	Humans ; Mental Disorders/diagnosis ; Mental Health ; Mood Disorders ; Pandemics ; Recurrence ; Smartphone
Language	English
Publishing date	2023-12-13
Publishing country	Canada
Document type	Journal Article ; Research Support, Non-U.S. Gov't ; Review ; Systematic Review
ZDB-ID	2028830-X
ISSN	1438-8871 ; 1438-8871
ISSN (online)	1438-8871
ISSN	1438-8871
DOI	10.2196/46778
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Article ; Online: Low cardiac frequency associated with higher number of extrasistoles in a computational model of Brugada Syndrome.

Seghetti, Paolo / Biasi, Niccolo / Laurino, Marco / Tognetti, Alessandro

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2022 Volume 2022, Page(s) 2262–2265

Abstract: Brugada Syndrome is a form of idiopathic ventricular fibrillation, to date there is no definitive theory about how ventricular fibrillation is initiated or its substrate. Starting from the clinical observation that cardiac episodes are more frequent at ... ...

Abstract	Brugada Syndrome is a form of idiopathic ventricular fibrillation, to date there is no definitive theory about how ventricular fibrillation is initiated or its substrate. Starting from the clinical observation that cardiac episodes are more frequent at rest, we developed a model in order to study the effect of cardiac frequency on reentrant activity. Our results suggest that the combination of arrhythmic substrate and cardiac frequency has a role in the insurgence of cardiac arrhythmia.
MeSH term(s)	Brugada Syndrome/complications ; Brugada Syndrome/diagnosis ; Electrocardiography ; Heart ; Humans ; Ventricular Fibrillation
Language	English
Publishing date	2022-09-09
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC48229.2022.9871551
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Article ; Online: Diffuse fibrosis and repolarization disorders explain ventricular arrhythmias in Brugada syndrome: a computational study.

Biasi, Niccoló / Seghetti, Paolo / Tognetti, Alessandro

Scientific reports

2022 Volume 12, Issue 1, Page(s) 8530

Abstract: In this work, we reported a computational study to quantitatively determine the individual contributions of three candidate arrhythmic factors associated with Brugada Syndrome. In particular, we focused our analysis on the role of structural ... ...

Abstract	In this work, we reported a computational study to quantitatively determine the individual contributions of three candidate arrhythmic factors associated with Brugada Syndrome. In particular, we focused our analysis on the role of structural abnormalities, dispersion of repolarization, and size of the diseased region. We developed a human phenomenological model capable of replicating the action potential characteristics both in Brugada Syndrome and in healthy conditions. Inspired by physiological observations, we employed the phenomenological model in a 2D geometry resembling the pathological RVOT coupled with healthy epicardial tissue. We assessed the insurgence of sustained reentry as a function of electrophysiological and structural abnormalities. Our computational study indicates that both structural and repolarization abnormalities are essential to induce sustained reentry. Furthermore, our results suggest that neither dispersion of repolarization nor structural abnormalities are sufficient on their own to induce sustained reentry. It should be noted how our study seems to explain an arrhythmic mechanism that unifies the classic repolarization and depolarization hypotheses of the pathophysiology of the Brugada Syndrome. Finally, we believe that this work may offer a new perspective on the computational and clinical investigation of Brugada Syndrome and its arrhythmic behaviour.
MeSH term(s)	Action Potentials/physiology ; Arrhythmias, Cardiac/pathology ; Brugada Syndrome ; Electrocardiography/methods ; Fibrosis ; Humans
Language	English
Publishing date	2022-05-20
Publishing country	England
Document type	Journal Article
ZDB-ID	2615211-3
ISSN	2045-2322 ; 2045-2322
ISSN (online)	2045-2322
ISSN	2045-2322
DOI	10.1038/s41598-022-12239-9
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Article ; Online: A transmurally heterogeneous model of the ventricular tissue and its application for simulation of Brugada Syndrome.

Biasi, Niccolo / Seghetti, Paolo / Tognetti, Alessandro

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2022 Volume 2022, Page(s) 3951–3954

Abstract: We present a transmurally heterogeneous phe-nomenological model of ventricular tissue that is designed to reproduce the most important features of action potential prop-agation of endocardial, midmyocardial, and epicardial tissue. Our model consists of ... ...

Abstract	We present a transmurally heterogeneous phe-nomenological model of ventricular tissue that is designed to reproduce the most important features of action potential prop-agation of endocardial, midmyocardial, and epicardial tissue. Our model consists of only 3 variables and 20 parameters. Therefore, it is highly computational efficient and easy to fit to experimental data. We exploited our myocyte model to simulate action potential propagation in a 3D slab of cardiac tissue both in healthy conditions and in presence of Brugada syndrome. The results show that our model can accurately reproduce the transmural heterogeneity of the ventricular wall and the main characteristics of electrocardiographic pattern both in healthy and pathological conditions.
MeSH term(s)	Action Potentials ; Brugada Syndrome ; Computer Simulation ; Endocardium ; Heart Ventricles ; Humans
Language	English
Publishing date	2022-09-10
Publishing country	United States
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC48229.2022.9871482
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Article ; Online: Moving Auto-Correlation Window Approach for Heart Rate Estimation in Ballistocardiography Extracted by Mattress-Integrated Accelerometers.

Laurino, Marco / Menicucci, Danilo / Gemignani, Angelo / Carbonaro, Nicola / Tognetti, Alessandro

Sensors (Basel, Switzerland)

2020 Volume 20, Issue 18

Abstract: Continuous heart monitoring is essential for early detection and diagnosis of cardiovascular diseases, which are key factors for the evaluation of health status in the general population. Therefore, in the future, it will be increasingly important to ... ...

Abstract	Continuous heart monitoring is essential for early detection and diagnosis of cardiovascular diseases, which are key factors for the evaluation of health status in the general population. Therefore, in the future, it will be increasingly important to develop unobtrusive and transparent cardiac monitoring technologies for the population. The possible approaches are the development of wearable technologies or the integration of sensors in daily-life objects. We developed a smart bed for monitoring cardiorespiratory functions during the night or in the case of continuous monitoring of bedridden patients. The mattress includes three accelerometers for the estimation of the ballistocardiogram (BCG). BCG signal is generated due to the vibrational activity of the body in response to the cardiac ejection of blood. BCG is a promising technique but is usually replaced by electrocardiogram due to the difficulty involved in detecting and processing the BCG signals. In this work, we describe a new algorithm for heart parameter extraction from the BCG signal, based on a moving auto-correlation sliding-window. We tested our method on a group of volunteers with the simultaneous co-registration of electrocardiogram (ECG) using a single-lead configuration. Comparisons with ECG reference signals indicated that the algorithm performed satisfactorily. The results presented demonstrate that valuable cardiac information can be obtained from the BCG signal extracted by low cost sensors integrated in the mattress. Thus, a continuous unobtrusive heart-monitoring through a smart bed is now feasible.
MeSH term(s)	Accelerometry/instrumentation ; Ballistocardiography ; Electrocardiography ; Heart ; Heart Rate ; Humans ; Signal Processing, Computer-Assisted
Keywords	covid19
Language	English
Publishing date	2020-09-22
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2052857-7
ISSN	1424-8220 ; 1424-8220
ISSN (online)	1424-8220
ISSN	1424-8220
DOI	10.3390/s20185438
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Article ; Online: Ambiguity-Free Optical-Inertial Tracking for Augmented Reality Headsets.

Cutolo, Fabrizio / Mamone, Virginia / Carbonaro, Nicola / Ferrari, Vincenzo / Tognetti, Alessandro

Sensors (Basel, Switzerland)

2020 Volume 20, Issue 5

Abstract: The increasing capability of computing power and mobile graphics has made possible the release of self-contained augmented reality (AR) headsets featuring efficient head-anchored tracking solutions. Ego motion estimation based on well-established ... ...

Abstract	The increasing capability of computing power and mobile graphics has made possible the release of self-contained augmented reality (AR) headsets featuring efficient head-anchored tracking solutions. Ego motion estimation based on well-established infrared tracking of markers ensures sufficient accuracy and robustness. Unfortunately, wearable visible-light stereo cameras with short baseline and operating under uncontrolled lighting conditions suffer from tracking failures and ambiguities in pose estimation. To improve the accuracy of optical self-tracking and its resiliency to marker occlusions, degraded camera calibrations, and inconsistent lighting, in this work we propose a sensor fusion approach based on Kalman filtering that integrates optical tracking data with inertial tracking data when computing motion correlation. In order to measure improvements in AR overlay accuracy, experiments are performed with a custom-made AR headset designed for supporting complex manual tasks performed under direct vision. Experimental results show that the proposed solution improves the head-mounted display (HMD) tracking accuracy by one third and improves the robustness by also capturing the orientation of the target scene when some of the markers are occluded and when the optical tracking yields unstable and/or ambiguous results due to the limitations of using head-anchored stereo tracking cameras under uncontrollable lighting conditions.
Language	English
Publishing date	2020-03-06
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2052857-7
ISSN	1424-8220 ; 1424-8220
ISSN (online)	1424-8220
ISSN	1424-8220
DOI	10.3390/s20051444
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Article ; Online: Tele-monitoring and tele-rehabilitation of the shoulder muscular-skeletal diseases through wearable systems.

Carbonaro, Nicola / Lucchesi, Irene / Lorusssi, Federico / Tognetti, Alessandro

Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual International Conference

2018 Volume 2018, Page(s) 4410–4413

Abstract: In this work we present the development and preliminary testing of a wearable-technology-enabled platform for the remote rehabilitation of a large number of shoulder muscular-skeletal diseases. The presented system (Shoulphy) is conceived to lead and ... ...

Abstract	In this work we present the development and preliminary testing of a wearable-technology-enabled platform for the remote rehabilitation of a large number of shoulder muscular-skeletal diseases. The presented system (Shoulphy) is conceived to lead and assess the patient, wearing a minimal set of inertial sensors, through personalized physical rehabilitation programs under the remote supervision of the physician/therapist. We have introduced a minimal inertial sensor set and an associated biomechanical reconstruction method based on a bi-articular model of the shoulder. We have tested the system in classical shoulder rehabilitation exercises and we have demonstrated that the system is able to discriminate between correct and compensatory movement strategies.
MeSH term(s)	Exercise Therapy ; Humans ; Movement ; Shoulder ; Telerehabilitation ; Wearable Electronic Devices
Language	English
Publishing date	2018-09-17
Publishing country	United States
Document type	Journal Article
ISSN	2694-0604
ISSN (online)	2694-0604
DOI	10.1109/EMBC.2018.8513371
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Article ; Online: Exploiting Resistive Matrix Technology to Build a Stretchable Sensorised Sock for Gait Analysis in Daily Life.

Carbonaro, Nicola / Arcarisi, Lucia / Marinai, Carlotta / Laurino, Marco / Di Rienzo, Francesco / Vallati, Carlo / Tognetti, Alessandro

Sensors (Basel, Switzerland)

2022 Volume 22, Issue 5

Abstract: We describe the development and preliminary evaluation of an innovative low-cost wearable device for gait analysis. We have developed a sensorized sock equipped with 32 piezoresistive textile-based sensors integrated in the heel and metatarsal areas for ... ...

Abstract	We describe the development and preliminary evaluation of an innovative low-cost wearable device for gait analysis. We have developed a sensorized sock equipped with 32 piezoresistive textile-based sensors integrated in the heel and metatarsal areas for the detection of signals associated with the contact pressures generated during walking phases. To build the sock, we applied a sensing patch on a commercially available sock. The sensing patch is a stretchable circuit based on the resistive matrix method, in which conductive stripes, based on conductive inks, are coupled with piezoresistive fabrics to form sensing elements. In our sensorized sock, we introduced many relevant improvements to overcome the limitations of the classical resistive matrix method. We preliminary evaluated the sensorized sock on five healthy subjects by performing a total of 80 walking tasks at different speeds for a known distance. Comparison of step count and step-to-step frequency versus reference measurements showed a high correlation between the estimated measure and the real one.
MeSH term(s)	Gait Analysis ; Humans ; Technology ; Textiles ; Walking ; Wearable Electronic Devices
Language	English
Publishing date	2022-02-24
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2052857-7
ISSN	1424-8220 ; 1424-8220
ISSN (online)	1424-8220
ISSN	1424-8220
DOI	10.3390/s22051761
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