Pub Date : 2025-12-23DOI: 10.1016/j.bbe.2025.12.003
Xinyi Han , Mathieu Specklin , Smaine Kouidri , Louise Koskas , Farid Bakir , Jean-Michel Davaine
This numerical study evaluates the impact of including the aortic arch in in-vivo and in-silico studies, by comparing an abdominal healthy aorta model to an aneurysmal one. CFD simulations were performed using OpenFOAM, with patient-specific blood flow data. Wall shear stress indices (TAWSS, OSI, RRT) and vortex distributions (Q criterion) were analyzed. The results show that the aortic arch amplifies blood flow disturbances, leading to a reduction in TAWSS and an increase in OSI, which may enhance the risk of potential thrombosis. Simplified models without the arch underestimate these effects. The influence of the aortic arch is more pronounced in the abdominal healthy aorta than in the abdominal aortic aneurysm, highlighting the importance of including it in hemodynamic simulations for a more accurate risk assessment.
{"title":"Numerical investigations on the impact of aortic arch inclusion on hemodynamics of abdominal healthy and aneurysmal aorta","authors":"Xinyi Han , Mathieu Specklin , Smaine Kouidri , Louise Koskas , Farid Bakir , Jean-Michel Davaine","doi":"10.1016/j.bbe.2025.12.003","DOIUrl":"10.1016/j.bbe.2025.12.003","url":null,"abstract":"<div><div>This numerical study evaluates the impact of including the aortic arch in in-vivo and in-silico studies, by comparing an abdominal healthy aorta model to an aneurysmal one. CFD simulations were performed using OpenFOAM, with patient-specific blood flow data. Wall shear stress indices (TAWSS, OSI, RRT) and vortex distributions (Q criterion) were analyzed. The results show that the aortic arch amplifies blood flow disturbances, leading to a reduction in TAWSS and an increase in OSI, which may enhance the risk of potential thrombosis. Simplified models without the arch underestimate these effects. The influence of the aortic arch is more pronounced in the abdominal healthy aorta than in the abdominal aortic aneurysm, highlighting the importance of including it in hemodynamic simulations for a more accurate risk assessment.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 76-94"},"PeriodicalIF":6.6,"publicationDate":"2025-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-19DOI: 10.1016/j.bbe.2025.12.002
Marcin Kołodziej , Andrzej Majkowski , Marcin Jurczak , Andrzej Rysz , Bruno Andò , Remigiusz J. Rak
A method for detecting epileptic spikes in EEG recordings that leverages additional EMG channels to identify and remove muscle artifacts is presented. Unlike conventional approaches, our method models the uneven propagation of muscle artifacts by applying a filter bank and linear regression to clean the EEG signal. Spike detection is then performed using template matching with user-defined parameters, such as amplitude and duration, designed for neurophysiological interpretability. To validate our approach, we developed a dedicated database comprising EEG and EMG recordings from 20 participants. Artificial triangular spikes were added to EEG segments contaminated with muscle artifacts, creating numerous examples of spikes masked by artifacts. This dataset enabled a systematic evaluation of both preprocessing and spike detection techniques. Our method achieved a sensitivity of 0.88, specificity of 1.00, and precision of 0.79 in the detection of simulated spikes. Further testing on real EEG data with interictal spikes and added muscle artifacts yielded a sensitivity of 0.83, specificity of 0.99, and precision of 0.71, demonstrating robust performance even under challenging conditions. These results indicate that incorporating EMG channels to account for muscle activity substantially improves the effectiveness of EEG signal analysis. The proposed approach facilitates reliable detection of epileptic spikes, even when masked by muscle artifacts, and allows neurophysiologists to tailor detection criteria to specific amplitude and temporal features.
{"title":"Method for epileptic spike detection in EEG signals contaminated by muscle artifacts","authors":"Marcin Kołodziej , Andrzej Majkowski , Marcin Jurczak , Andrzej Rysz , Bruno Andò , Remigiusz J. Rak","doi":"10.1016/j.bbe.2025.12.002","DOIUrl":"10.1016/j.bbe.2025.12.002","url":null,"abstract":"<div><div>A method for detecting epileptic spikes in EEG recordings that leverages additional EMG channels to identify and remove muscle artifacts is presented. Unlike conventional approaches, our method models the uneven propagation of muscle artifacts by applying a filter bank and linear regression to clean the EEG signal. Spike detection is then performed using template matching with user-defined parameters, such as amplitude and duration, designed for neurophysiological interpretability. To validate our approach, we developed a dedicated database comprising EEG and EMG recordings from 20 participants. Artificial triangular spikes were added to EEG segments contaminated with muscle artifacts, creating numerous examples of spikes masked by artifacts. This dataset enabled a systematic evaluation of both preprocessing and spike detection techniques. Our method achieved a sensitivity of 0.88, specificity of 1.00, and precision of 0.79 in the detection of simulated spikes. Further testing on real EEG data with interictal spikes and added muscle artifacts yielded a sensitivity of 0.83, specificity of 0.99, and precision of 0.71, demonstrating robust performance even under challenging conditions. These results indicate that incorporating EMG channels to account for muscle activity substantially improves the effectiveness of EEG signal analysis. The proposed approach facilitates reliable detection of epileptic spikes, even when masked by muscle artifacts, and allows neurophysiologists to tailor detection criteria to specific amplitude and temporal features.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 50-75"},"PeriodicalIF":6.6,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-05DOI: 10.1016/j.bbe.2025.11.008
Agnieszka Paziewska-Nowak , Marcin Urbanowicz , Marek Dawgul , Kornelia Bobrowska , Anna Sołdatowska , Marcin Ekman , Dorota G. Pijanowska
pH monitoring in biological fluids plays a critical role in clinical diagnostics and therapeutic management. This study presents a novel solid-contact pH electrode fabricated using a direct-printed (DP) graphite (Gr) electrode on a flexible substrate, followed by an electropolymerized hydrophobic polyazulene (pAz) transducing layer, and an ion-selective membrane (ISM). The pH electrode was paired with a miniaturized solid-state Ag/AgCl reference electrode incorporating a photopolymerized PVA-KCl matrix. The miniaturized reference electrode exhibited excellent potential stability (±2.5 mV across pH 2–11), and minimal signal drift (10 µV/h). The miniaturized pH electrode exhibited a sensitivity of 55.7 mV/dec, with a rapid response time of 6 s (vs. Orion™ ROSS Ultra™ reference electrode) or 42 s (vs. miniaturized solid-state reference electrode) and a linear response over the pH range of 2–10. The pH electrode demonstrated excellent analytical performance in diverse biological fluids, including urine, serum, saliva, and surgical drain fluid, closely matching the performance of a laboratory-grade combined glass pH electrode. These results underscore the potential of the proposed platform as a reliable and technologically scalable tool for real-time pH assessment in biomedical applications.
{"title":"Highly stable direct-printed polyazulene-based miniaturized electrode for pH analysis in human body fluids","authors":"Agnieszka Paziewska-Nowak , Marcin Urbanowicz , Marek Dawgul , Kornelia Bobrowska , Anna Sołdatowska , Marcin Ekman , Dorota G. Pijanowska","doi":"10.1016/j.bbe.2025.11.008","DOIUrl":"10.1016/j.bbe.2025.11.008","url":null,"abstract":"<div><div>pH monitoring in biological fluids plays a critical role in clinical diagnostics and therapeutic management. This study presents a novel solid-contact pH electrode fabricated using a direct-printed (DP) graphite (Gr) electrode on a flexible substrate, followed by an electropolymerized hydrophobic polyazulene (pAz) transducing layer, and an ion-selective membrane (ISM). The pH electrode was paired with a miniaturized solid-state Ag/AgCl reference electrode incorporating a photopolymerized PVA-KCl matrix. The miniaturized reference electrode exhibited excellent potential stability (±2.5 mV across pH 2–11), and minimal signal drift (10 µV/h). The miniaturized pH electrode exhibited a sensitivity of 55.7 mV/dec, with a rapid response time of 6 s (vs. Orion™ ROSS Ultra™ reference electrode) or 42 s (vs. miniaturized solid-state reference electrode) and a linear response over the pH range of 2–10. The pH electrode demonstrated excellent analytical performance in diverse biological fluids, including urine, serum, saliva, and surgical drain fluid, closely matching the performance of a laboratory-grade combined glass pH electrode. These results underscore the potential of the proposed platform as a reliable and technologically scalable tool for real-time pH assessment in biomedical applications.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 40-49"},"PeriodicalIF":6.6,"publicationDate":"2025-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stroke-induced decoupling of neural control and biomechanics impairs walking. The mechanism by which exoskeleton modulates neuro-biomechanical coupling through mechanical support and assistance remains unclear. This study aims to reveal the coupling relationship between neural control and biomechanics in exoskeleton assisted walking for stroke patients through multimodal analysis. Sixteen stroke and sixteen healthy subjects participated, with kinematic, surface electromyography, and cerebral hemodynamic data collected in 4 exoskeleton assisted walking conditions. We analyzed spatiotemporal parameters, movement coordination, muscle synergy, cortical activation and functional connectivity, as well as lateralization and neural network parameters using hierarchical generalized additive mixed-effects model regression and distance correlation to explore the dynamic nonlinear effects of neuro-biomechanics and symmetry associations. Subjects after stroke showed disturbed movement coordination, simplified muscle synergy, and suppressed cortical activation. The exoskeleton activated ankle anti-phase coordination and partially restores muscle synergy, but led to reduced multi-joint coordination and increased gait speed asymmetry. Cortical activation and functional connectivity decreased for stroke subjects, and cognitively oriented lateralization as well as neural network integration efficiency were increased with exoskeleton intervention. Neuro-biomechanical coupling results indicated that subjects after stroke relied on centralized modulation of supplementary motor area activation to integrate motor planning and execution, and dynamic laterality fluctuation of premotor cortex reflected motor control rhythms by regulating movement variability. The exoskeleton reconfigured neuro-biomechanical coupling, prompting a shift from pathological compensatory discoordination toward motor planning-orientated adaptive control strategy, and providing a rationale for rehabilitation assistance targeting the adaptive reorganization of motor function.
{"title":"Neuro-biomechanical coupling in exoskeleton assisted walking for stroke patients demonstrates adaptive compensation","authors":"Yujia Gao, Jiayi Sun, Chenhao Li, Yufeng Lin, Zilin Wang, Chenghua Jiang, Wenxin Niu","doi":"10.1016/j.bbe.2025.11.007","DOIUrl":"10.1016/j.bbe.2025.11.007","url":null,"abstract":"<div><div>Stroke-induced decoupling of neural control and biomechanics impairs walking. The mechanism by which exoskeleton modulates neuro-biomechanical coupling through mechanical support and assistance remains unclear. This study aims to reveal the coupling relationship between neural control and biomechanics in exoskeleton assisted walking for stroke patients through multimodal analysis. Sixteen stroke and sixteen healthy subjects participated, with kinematic, surface electromyography, and cerebral hemodynamic data collected in 4 exoskeleton assisted walking conditions. We analyzed spatiotemporal parameters, movement coordination, muscle synergy, cortical activation and functional connectivity, as well as lateralization and neural network parameters using hierarchical generalized additive mixed-effects model regression and distance correlation to explore the dynamic nonlinear effects of neuro-biomechanics and symmetry associations. Subjects after stroke showed disturbed movement coordination, simplified muscle synergy, and suppressed cortical activation. The exoskeleton activated ankle anti-phase coordination and partially restores muscle synergy, but led to reduced multi-joint coordination and increased gait speed asymmetry. Cortical activation and functional connectivity decreased for stroke subjects, and cognitively oriented lateralization as well as neural network integration efficiency were increased with exoskeleton intervention. Neuro-biomechanical coupling results indicated that subjects after stroke relied on centralized modulation of supplementary motor area activation to integrate motor planning and execution, and dynamic laterality fluctuation of premotor cortex reflected motor control rhythms by regulating movement variability. The exoskeleton reconfigured neuro-biomechanical coupling, prompting a shift from pathological compensatory discoordination toward motor planning-orientated adaptive control strategy, and providing a rationale for rehabilitation assistance targeting the adaptive reorganization of motor function.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 19-32"},"PeriodicalIF":6.6,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-04DOI: 10.1016/j.bbe.2025.11.002
Matej Daniel , Jan Votava , Júlia Bodnárová , Adam Kratochvíll , Zbyněk Šika , David Pokorný , Petr Fulín
The shoulder’s dynamic function is largely influenced by scapulohumeral rhythm (SHR), a coordinated movement of the scapula and humerus that facilitates a safe range of motion. While SHR has been described and quantified in terms of shoulder kinematics, its specific contribution to glenohumeral joint stability. This study aims to estimate the impact of SHR on glenohumeral stability using a biomechanical model. A five-segment musculoskeletal model based on the work of Wu et al. (2016) was implemented in OpenSim. Three SHR patterns and two loading scenarios were evaluated: a fixed scapula, a humeral-to-scapular motion ratio, and an experimentally measured SHR with free abduction or abduction while holding a 2 kg weight in the hand. Muscle forces and glenohumeral stability ratios were calculated using static optimization, and the model predictions were compared to electromyography and in vivo joint force data. While glenohumeral contact forces showed minimal variation across different SHR conditions, the stability ratio analysis revealed that the absence of SHR significantly increased the risk of joint instability. In scenarios without SHR, even small shoulder elevations resulted in overloading of the superior glenoid. The addition of weight further destabilized the joint, while substantially increasing glenohumeral force. SHR does not reduce the overall glenohumeral load but plays a critical role in maintaining glenohumeral stability, particularly during early phases of shoulder elevation and when holding additional weight. These findings highlight the importance of scapular kinematics in shoulder joint function and may have implications for managing shoulder pathologies such as rotator cuff tears and impingement, where scapular motion is often compromised.
{"title":"Scapulohumeral rhythm preserves glenohumeral stability: Insights from a biomechanical simulation","authors":"Matej Daniel , Jan Votava , Júlia Bodnárová , Adam Kratochvíll , Zbyněk Šika , David Pokorný , Petr Fulín","doi":"10.1016/j.bbe.2025.11.002","DOIUrl":"10.1016/j.bbe.2025.11.002","url":null,"abstract":"<div><div>The shoulder’s dynamic function is largely influenced by scapulohumeral rhythm (SHR), a coordinated movement of the scapula and humerus that facilitates a safe range of motion. While SHR has been described and quantified in terms of shoulder kinematics, its specific contribution to glenohumeral joint stability. This study aims to estimate the impact of SHR on glenohumeral stability using a biomechanical model. A five-segment musculoskeletal model based on the work of Wu et al. (2016) was implemented in OpenSim. Three SHR patterns and two loading scenarios were evaluated: a fixed scapula, a humeral-to-scapular motion ratio, and an experimentally measured SHR with free abduction or abduction while holding a 2 kg weight in the hand. Muscle forces and glenohumeral stability ratios were calculated using static optimization, and the model predictions were compared to electromyography and in vivo joint force data. While glenohumeral contact forces showed minimal variation across different SHR conditions, the stability ratio analysis revealed that the absence of SHR significantly increased the risk of joint instability. In scenarios without SHR, even small shoulder elevations resulted in overloading of the superior glenoid. The addition of weight further destabilized the joint, while substantially increasing glenohumeral force. SHR does not reduce the overall glenohumeral load but plays a critical role in maintaining glenohumeral stability, particularly during early phases of shoulder elevation and when holding additional weight. These findings highlight the importance of scapular kinematics in shoulder joint function and may have implications for managing shoulder pathologies such as rotator cuff tears and impingement, where scapular motion is often compromised.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 33-39"},"PeriodicalIF":6.6,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-03DOI: 10.1016/j.bbe.2025.11.006
Ilaria Toniolo , Emanuele Luigi Carniel , Claudio Fiorillo , Giuseppe Quero , Silvana Perretta , Alice Berardo
Endoscopic Sleeve Gastroplasty (ESG) is currently being used successfully in people with obesity. However, potential long-term side effects are still unknown. Computational biomechanics has emerged as a valid tool to improve the intervention effectiveness.
The aim of this work is to provide an in silico framework to estimate stomach mechanics, as volumetric capacity, structural stiffness, and wall tissue strain, in response to food intake before and after ESG. A cohort of patients who underwent ESG was studied to rationally analyze the reduction in gastric volume and the changes in structural response and strain distribution. Computational predictions were compared with Magnetic Resonance Imaging (MRI) data from post-operative stomachs, allowing the reliability and reproducibility of the methodology to be assessed. Significant differences in stomach mechanics before and after surgery were observed, considering both structural stiffness and tissue strain distribution. This difference may lead to improper activation of mechanoreceptors and thus to variations in satiety after ESG.
The results confirm the suitability of the in silico approach for evaluating bariatric surgery in the short-term, because it shed light on the reduction of stomach capacity and pressurization depending on the amount of food ingested, on the variation of tissue strain distribution, giving to the surgeon information that are currently not available. Leveraging computational modeling may help prevent complications, such as reflux or misplacement of sutures, and enhance outcomes by prescribing gastric-wall loading conditions associated with lower postoperative weight-regain rates.
{"title":"Tailoring Endoscopic sleeve gastroplasty: computational biomechanics for the evaluation and prediction of post-surgical outcomes","authors":"Ilaria Toniolo , Emanuele Luigi Carniel , Claudio Fiorillo , Giuseppe Quero , Silvana Perretta , Alice Berardo","doi":"10.1016/j.bbe.2025.11.006","DOIUrl":"10.1016/j.bbe.2025.11.006","url":null,"abstract":"<div><div>Endoscopic Sleeve Gastroplasty (ESG) is currently being used successfully in people with obesity. However, potential long-term side effects are still unknown. Computational biomechanics has emerged as a valid tool to improve the intervention effectiveness.</div><div>The aim of this work is to provide an in silico framework to estimate stomach mechanics, as volumetric capacity, structural stiffness, and wall tissue strain, in response to food intake before and after ESG. A cohort of patients who underwent ESG was studied to rationally analyze the reduction in gastric volume and the changes in structural response and strain distribution. Computational predictions were compared with Magnetic Resonance Imaging (MRI) data from post-operative stomachs, allowing the reliability and reproducibility of the methodology to be assessed. Significant differences in stomach mechanics before and after surgery were observed, considering both structural stiffness and tissue strain distribution. This difference may lead to improper activation of mechanoreceptors and thus to variations in satiety after ESG.</div><div>The results confirm the suitability of the in silico approach for evaluating bariatric surgery in the short-term, because it shed light on the reduction of stomach capacity and pressurization depending on the amount of food ingested, on the variation of tissue strain distribution, giving to the surgeon information that are currently not available. Leveraging computational modeling may help prevent complications, such as reflux or misplacement of sutures, and enhance outcomes by prescribing gastric-wall loading conditions associated with lower postoperative weight-regain rates.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 9-18"},"PeriodicalIF":6.6,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145685164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Human postural stability represents a complex, nonlinear system influenced by a range of biomechanical and environmental factors. The trajectories of the center of pressure (CoP) serve as key indicators of this system’s underlying dynamics and are increasingly being analyzed using nonlinear methods. However, the impact of surface-induced instability during gait remains underexplored. This study aimed to analyze CoP behavior during gait on stable (dry) and unstable (slippery) surfaces by testing three hypotheses: (1) task-induced instability is associated with an increase in CoP complexity; (2) individual variability amplifies dynamic fluctuations under unstable conditions; and (3) repeated exposure to the task attenuates this complexity. Twenty healthy young males completed each walking task three times. CoP dynamics were quantified using nonlinear analyses, including phase-space reconstruction (embedding dimension and time lag) and correlation dimension (CD).
Complexity metrics, specifically the optimal embedding dimension and CD, were significantly elevated during the slippery surface condition, clearly distinguishing between the two task environments (p < 0.001, classification accuracy > 90 %). The greater variability in features observed under the slippery condition suggested broader dynamic adaptations to instability. Additionally, the reduction in CD across repeated trials indicated a moderating effect of prior exposure.
The findings support all three hypotheses, demonstrating the effectiveness of CoP-based nonlinear measures in capturing adaptive postural responses to changing stability demands. This study contributes a novel multi-trial nonlinear analysis approach for evaluating dynamic postural control under environmental challenges.
{"title":"A Complexity-Based analysis of postural stability dynamics during gait on dry and slippery surfaces","authors":"Mahdi Yousefi Azar Khanian , Zahra Sadat Hosseni , S.Mohammadreza Hashemi Gholpayeghani , Mostafa Rostami","doi":"10.1016/j.bbe.2025.11.005","DOIUrl":"10.1016/j.bbe.2025.11.005","url":null,"abstract":"<div><div>Human postural stability represents a complex, nonlinear system influenced by a range of biomechanical and environmental factors. The trajectories of the center of pressure (CoP) serve as key indicators of this system’s underlying dynamics and are increasingly being analyzed using nonlinear methods. However, the impact of surface-induced instability during gait remains underexplored. This study aimed to analyze CoP behavior during gait on stable (dry) and unstable (slippery) surfaces by testing three hypotheses: (1) task-induced instability is associated with an increase in CoP complexity; (2) individual variability amplifies dynamic fluctuations under unstable conditions; and (3) repeated exposure to the task attenuates this complexity. Twenty healthy young males completed each walking task three times. CoP dynamics were quantified using nonlinear analyses, including phase-space reconstruction (embedding dimension and time lag) and correlation dimension (CD).</div><div>Complexity metrics, specifically the optimal embedding dimension and CD, were significantly elevated during the slippery surface condition, clearly distinguishing between the two task environments (p < 0.001, classification accuracy > 90 %). The greater variability in features observed under the slippery condition suggested broader dynamic adaptations to instability. Additionally, the reduction in CD across repeated trials indicated a moderating effect of prior exposure.</div><div>The findings support all three hypotheses, demonstrating the effectiveness of CoP-based nonlinear measures in capturing adaptive postural responses to changing stability demands. This study contributes a novel multi-trial nonlinear analysis approach for evaluating dynamic postural control under environmental challenges.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"46 1","pages":"Pages 1-8"},"PeriodicalIF":6.6,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145600576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-01DOI: 10.1016/j.bbe.2025.10.002
Zhenxia Mu , Ben Liu , Yicheng Han , Lihui Zhuang , Xiaoyu Qiu , Heyu Ding , Shusheng Gong , Guopeng Wang , Bin Gao , Youjun Liu , Shifeng Yang , Zhenchang Wang , Pengfei Zhao , Ximing Wang
Hemodynamic factors play a crucial role in the pathogenesis of venous pulsatile tinnitus (PT). The selection of an appropriate blood viscosity model is therefore essential for accurately capturing hemodynamic characteristics in numerical simulations. This study aimed to investigate and compare the effects of different blood rheology models on hemodynamic parameters in patients with venous PT. Numerical simulation of pulsatile blood flow was conducted in three-dimensional patient-specific models with sigmoid sinuses wall dehiscence (SSWD) accompanied by sigmoid sinuses diverticulum (SSD) or transverse sinus stenosis. Different blood rheology models were employed in the simulations, including the Newtonian, Power law, Carreau, and Herschel-Bulkley models. Results demonstrated that unfavorable hemodynamics, characterized by high-velocity patterns and abnormal distributions of wall pressure, wall shear stress (WSS), and time-average WSS (TAWSS) in specific SSD and SSWD regions, could increase the risk of venous PT. Both Newtonian and non-Newtonian models predicted comparable distributions of hemodynamic parameters. However, differences in magnitude were observed, particularly in the SSD and SSWD regions. The Power law model exhibited the most pronounced differences, predicting the lowest velocity in the SSD region and the highest wall pressure, WSS, and TAWSS in the SSWD region. The Herschel-Bulkley model showed similar trends but with less extreme magnitudes. The Carreau model was closely aligned with the Newtonian model. Although the Newtonian model generally predicted hemodynamic parameter distributions comparable to those of non-Newtonian models, marked differences were observed in key regions (SSD and SSWD) critically involved in venous PT pathogenesis. Therefore, selecting an appropriate viscosity model is essential for accurately assessing hemodynamic characteristics within these specific regions.
{"title":"Effect of non-Newtonian rheological models on pulsatile hemodynamics in patients-specific venous models of pulsatile tinnitus","authors":"Zhenxia Mu , Ben Liu , Yicheng Han , Lihui Zhuang , Xiaoyu Qiu , Heyu Ding , Shusheng Gong , Guopeng Wang , Bin Gao , Youjun Liu , Shifeng Yang , Zhenchang Wang , Pengfei Zhao , Ximing Wang","doi":"10.1016/j.bbe.2025.10.002","DOIUrl":"10.1016/j.bbe.2025.10.002","url":null,"abstract":"<div><div>Hemodynamic factors play a crucial role in the pathogenesis of venous pulsatile tinnitus (PT). The selection of an appropriate blood viscosity model is therefore essential for accurately capturing hemodynamic characteristics in numerical simulations. This study aimed to investigate and compare the effects of different blood rheology models on hemodynamic parameters in patients with venous PT. Numerical simulation of pulsatile blood flow was conducted in three-dimensional patient-specific models with sigmoid sinuses wall dehiscence (SSWD) accompanied by sigmoid sinuses diverticulum (SSD) or transverse sinus stenosis. Different blood rheology models were employed in the simulations, including the Newtonian, Power law, Carreau, and Herschel-Bulkley models. Results demonstrated that unfavorable hemodynamics, characterized by high-velocity patterns and abnormal distributions of wall pressure, wall shear stress (WSS), and time-average WSS (TAWSS) in specific SSD and SSWD regions, could increase the risk of venous PT. Both Newtonian and non-Newtonian models predicted comparable distributions of hemodynamic parameters. However, differences in magnitude were observed, particularly in the SSD and SSWD regions. The Power law model exhibited the most pronounced differences, predicting the lowest velocity in the SSD region and the highest wall pressure, WSS, and TAWSS in the SSWD region. The Herschel-Bulkley model showed similar trends but with less extreme magnitudes. The Carreau model was closely aligned with the Newtonian model. Although the Newtonian model generally predicted hemodynamic parameter distributions comparable to those of non-Newtonian models, marked differences were observed in key regions (SSD and SSWD) critically involved in venous PT pathogenesis. Therefore, selecting an appropriate viscosity model is essential for accurately assessing hemodynamic characteristics within these specific regions.</div></div>","PeriodicalId":55381,"journal":{"name":"Biocybernetics and Biomedical Engineering","volume":"45 4","pages":"Pages 630-641"},"PeriodicalIF":6.6,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical methods enable continuous, noninvasive cerebral blood flow (CBF) monitoring. Diffuse correlation spectroscopy (DCS) estimates CBF through temporal correlation analysis of scattered light but is limited by low detection throughput. Parallelizing DCS enhances performance but requires costly ultra-fast (∼1 MHz) detectors, complicating continuous measurements. An alternative approach analyzes spatial correlations using speckle contrast, inversely proportional to blood flow, captured with slower two-dimensional sensors. In this study, we present continuous-wave parallel interferometric near-infrared spectroscopy (CW-πNIRS), employing interferometry combined with a high-speed 2D camera, as a novel method uniquely suited for spatial correlation measurements. By leveraging interferometric detection, our approach provides a synthetic multi-exposure capability for direct quantitative comparisons between spatial (speckle contrast) and temporal (autocorrelation) methods for CBF monitoring. Numerical simulations, incorporating interferometric reference fields, and tissue-mimicking phantom validations demonstrated robust, and stable speckle contrast estimates. Finally, in vivo experiments confirmed the method’s potential for effective human cerebral blood flow monitoring, highlighting practical advantages and providing a clear pathway towards clinical implementation.
Breast cancer is the most common malignancy among women and leading cause of mortality. Accurate, non-invasive differentiation of benign and malignant lesions is a clinical priority to reduce unnecessary biopsies and enable timely treatment. Elastography and RF time series (RF TS) processing are effective ultrasound-based techniques for tissue characterization. To improve their accuracy, we introduced an innovative approach called RFTSDP (RF Time Series Dynamic Processing). In RFTSDP, data are recorded during mechanical stimulation, revealing tissue properties in RF echoes. Extracting relevant features enhances computer-aided methods and improves tissue classification and grading.
Materials and methods
An implement was developed to induce vibrations at different frequencies. Data were collected from ex-vivo tissues embedded in normal mimicking phantoms. Raw focused, raw, and beamformed ultrafast data were recorded under no stimulation, constant force, and various vibrational stimulations using the Supersonic Imaging Aixplorer ultrasound system. Features were extracted from each RF TS across the time, time–frequency, spectral, and non-linear domains. Multiple classifiers were evaluated, among which support vector machines with different kernels achieved the best results.
Results
Beyond the classification of cancerous versus non-cancerous tissue, we also classified different cancerous lesion types and graded invasive ductal carcinoma. The best results were achieved with beamformed ultrafast data under 65 Hz vibrational stimulation. The mean classification accuracies for 2-, 3-, and 5-class were 99.78 %, 99.06 % and 99.32 %, respectively.
Conclusions
The outcomes affirm that applying vibration, particularly at an optimal frequency, enhances breast tissue classification. The proposed method demonstrated efficacy not only in distinguishing between cancerous and non-cancerous lesions but also in grading cancerous tissues.
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