Biocybernetics and Biomedical Engineering最新文献_第3页

The influence of tissue conductivity uncertainty on the nerve activation thresholds in non-invasive electrical phrenic nerve stimulation 组织电导率不确定性对无创膈神经电刺激神经激活阈值的影响

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-10-01 DOI: 10.1016/j.bbe.2025.11.003

Laureen Wegert , Luca Di Rienzo , Lorenzo Codecasa , Sicheng An , Marek Ziolkowski , Alexander Hunold , Irene Lange , Tim Kalla , Jens Haueisen

Non-invasive phrenic nerve stimulation can be used to overcome diaphragm insufficiency caused by mechanical ventilation. Detailed models and electromagnetic simulations are used to suggest appropriate stimulation parameters, but require accurate tissue properties. However, a wide range of electrical conductivity values is known from the literature. Here, we aim to perform an uncertainty analysis of the nerve activation threshold and the potential distribution along the phrenic nerve due to uncertain tissue conductivites.

We built a generalized polynomial chaos (gPC) model to calculate the phrenic nerve activation threshold. It was based on a reduced order model of a detailed anatomical finite element model of the neck including 13 tissue types to calculate the potential distribution, followed by a biophysiological nerve model. The tissue conductivity values investigated here were for the compartments of fat, muscle, nerve, and soft tissue. Their influence on the nerve activation threshold was investigated by changing conductivity values of the single tissues and all tissues at a time within a Monte Carlo analysis using the gPC model.

The phrenic nerve activation threshold varied between 33.8 mA and 46.9 mA for the combined variation of the conductivity values. Sobol indices and global sensitivity coefficients indicated the highest influence for muscle conductivity value, followed by soft tissue, fat, and nerve tissue.

Our results may have implications for understanding the experimentally observed variation in individual phrenic nerve activation thresholds affected by physiological and pathological conductivity changes. Accurate electric properties of muscle and soft tissue and detailed geometric representations should be considered in electromagnetic simulations.

无创膈神经刺激可用于克服机械通气引起的膈肌功能不全。详细的模型和电磁模拟用于建议适当的刺激参数，但需要准确的组织特性。然而，从文献中已知电导率值的范围很广。在这里，我们的目的是进行神经激活阈值的不确定性分析和电位分布沿膈神经由于不确定的组织电导率。我们建立了广义多项式混沌（gPC）模型来计算膈神经的激活阈值。该方法基于包含13种组织类型的颈部详细解剖有限元模型的降阶模型计算电位分布，然后建立生物生理神经模型。这里研究的组织电导率值是针对脂肪、肌肉、神经和软组织的隔室。在使用gPC模型的蒙特卡罗分析中，通过改变单个组织和所有组织的电导率值，研究了它们对神经激活阈值的影响。电导率综合变化的膈神经激活阈值在33.8 ~ 46.9 mA之间。Sobol指数和整体敏感性系数对肌肉电导率的影响最大，其次是软组织、脂肪和神经组织。我们的结果可能有助于理解实验观察到的受生理和病理电导率变化影响的个体膈神经激活阈值的变化。电磁仿真应考虑肌肉和软组织的准确电特性和详细的几何表示。

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引用次数: 0

Estimating core body temperature from heart rate using a residual-compensated adaptive Kalman filter 利用残差补偿自适应卡尔曼滤波从心率估计核心体温

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-10-01 DOI: 10.1016/j.bbe.2025.10.001

Yuanzhe Zhao , Jeroen H.M. Bergmann

Accurate, real-time estimation of core body temperature is critical for preventing heat-related illness. While existing Kalman filter-based methods offer interpretable, single-input (heart rate) solutions, they are limited by fixed observation models that fail to capture the complex, non-linear, state-dependent dynamics of physiological signals.

To address this, we propose the Residual-Compensated Adaptive Kalman Filter (RCAKF), a novel hybrid framework. The RCAKF integrates a long short-term memory (LSTM) network to learn and correct structured, state-dependent errors in the observation model, alongside an adaptive noise estimator that dynamically adjusts for measurement uncertainty. This architecture enhances the classic Kalman filter with data-driven flexibility while maintaining its recursive structure and interpretability.

Evaluation was conducted on a controlled experimental dataset with 22 participants performing exercise and recovery under varied thermal conditions. Compared to five baseline models: extended Kalman filter (EKF: RMSE = 0.39 °C), the improved ECTemp model with a sigmoid observation function (ECTemp-S: RMSE = 0.40 °C), biphasic Kalman filter-based model (BKFB: RMSE = 0.48 °C), moving-average Kalman filter (MAKF: RMSE = 0.38 °C), and a standalone LSTM network (RMSE = 0.46 °C), RCAKF achieved the best accuracy with an RMSE of 0.31 °C.

By augmenting the Kalman filter with a learned residual correction and adaptive uncertainty, the RCAKF framework significantly enhances core temperature tracking from a single heart rate signal. Its accuracy and reliance on a single, common sensor make it a practical and promising solution for real-time deployment on wearable devices for safety monitoring.

准确、实时地估计核心体温对于预防与热有关的疾病至关重要。虽然现有的基于卡尔曼滤波的方法提供了可解释的单输入（心率）解决方案，但它们受到固定观察模型的限制，这些模型无法捕捉生理信号的复杂、非线性、状态依赖的动态。为了解决这个问题，我们提出了一种新的混合框架残余补偿自适应卡尔曼滤波器（RCAKF）。RCAKF集成了一个长短期记忆（LSTM）网络，用于学习和纠正观测模型中的结构化、状态相关错误，以及一个自适应噪声估计器，可动态调整测量不确定性。该结构增强了经典卡尔曼滤波器的数据驱动灵活性，同时保持了其递归结构和可解释性。对22名参与者在不同热条件下进行运动和恢复的受控实验数据集进行了评估。与扩展卡尔曼滤波（EKF: RMSE = 0.39°C）、具有s型观测函数的改进ECTemp模型（ECTemp- s: RMSE = 0.40°C）、基于双相卡尔曼滤波的模型（BKFB: RMSE = 0.48°C）、移动平均卡尔曼滤波（MAKF: RMSE = 0.38°C）和独立LSTM网络（RMSE = 0.46°C）等5种基线模型相比，RCAKF的RMSE为0.31°C，达到了最佳精度。通过使用学习残差校正和自适应不确定性增强卡尔曼滤波器，RCAKF框架显著增强了单次心率信号的核心温度跟踪。其准确性和对单个通用传感器的依赖使其成为可穿戴设备实时部署的实用且有前途的安全监控解决方案。

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引用次数: 0

Reevaluating performance in c-VEP BCIs: The impact of calibration time 重新评估c-VEP bci的性能：校准时间的影响

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-10-01 DOI: 10.1016/j.bbe.2025.10.006

Víctor Martínez-Cagigal , Eduardo Santamaría-Vázquez , Sergio Pérez-Velasco , Ana Martín-Fernández , Roberto Hornero

Code-modulated visual evoked potentials (c-VEP) have demonstrated high performance in non-invasive brain-computer interfaces (BCIs). Recently, research has begun to consider practical aspects such as visual comfort, where non-binary sequences and variations in the spatial frequency of stimuli play significant roles. However, calibration requirements remain underexplored in performance comparisons. This study aims to analyze a multi-variable tradeoff crucial to the practical application of c-VEP-based BCIs: decoding accuracy, decoding speed, and calibration time. Visual comfort is retrospectively evaluated using two pre-recorded datasets. Models were trained with increasing calibration cycles and tested across varying decoding times, depicting learning and decoding curves. The datasets comprised 32 healthy subjects, and featured different stimulus paradigms: plain non-binary stimuli and checkerboard-like binary stimuli with spatial frequency variations. Results showed that all conditions achieved over 97 % grand-averaged accuracy with sufficient calibration. However, a clear tradeoff emerged between calibration duration and performance. Achieving 95 % average accuracy within a 2 s decoding window required mean calibration durations of 28.7 ± 19.0 s for binary stimuli, or 148.7 ± 72.3 s for non-binary stimuli. The binary checkerboard-based condition with a spatial frequency of 1.2 c/º (C016) proved to be particularly effective, achieving over 95 % accuracy within 2 s decoding window using only 7.3 s of calibration, and reporting a significant improvement in visual comfort. A minimum calibration time of 1 min was considered essential to adequately estimate the brain response, critical in template-matching paradigms. In conclusion, achieving optimal c-VEP performance requires balancing calibration duration, decoding speed and accuracy, and visual comfort.

编码调制视觉诱发电位（c-VEP）在非侵入性脑机接口（bci）中表现出很高的性能。最近，研究开始考虑视觉舒适等实际方面，其中非二进制序列和刺激空间频率的变化起着重要作用。然而，在性能比较中，校准要求仍未得到充分探讨。本研究旨在分析对基于c- vep的bci的实际应用至关重要的多变量权衡：解码精度，解码速度和校准时间。使用两个预先记录的数据集对视觉舒适度进行回顾性评估。模型通过不断增加的校准周期进行训练，并在不同的解码时间内进行测试，描绘学习和解码曲线。数据集包括32名健康受试者，具有不同的刺激范式：普通的非二进制刺激和具有空间频率变化的棋盘状二进制刺激。结果表明，在充分校准的情况下，所有条件的大平均精度均达到97%以上。然而，在校准时间和性能之间出现了明显的权衡。要在2秒的解码窗口内达到95%的平均精度，二进制刺激的平均校准时间为28.7 ± 19.0 s，非二进制刺激的平均校准时间为148.7 ± 72.3 s。基于二进制棋盘的空间频率为1.2 c/º（C016）的条件被证明是特别有效的，仅使用7.3秒的校准时间，在2秒的解码窗口内达到95%以上的准确率，并报告了视觉舒适度的显着改善。最小校准时间1 min被认为是充分估计大脑反应的必要条件，在模板匹配范式中至关重要。总之，实现最佳的c-VEP性能需要平衡校准时间、解码速度和精度以及视觉舒适性。

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引用次数: 0

A novel class of rank tests for high-dimensional data with an application to Alzheimer’s disease 一类新的高维数据秩检验及其在阿尔茨海默病中的应用

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-10-01 DOI: 10.1016/j.bbe.2025.10.005

Jan Kalina , Jaromir Kukal , Oldrich Vysata

Electroencephalography (EEG) signals are widely used in neuroscience research and biomedical applications, particularly for comparative analyses between two cohorts: patients and control subjects. In EEG research, multivariate two-sample tests remain underused, while multiple comparison procedures are often misapplied as a substitute, leading to inadequate error control. Moreover, existing rank-based tests rely solely on Euclidean distances and lack robustness to outliers. The objective of this work is to develop and evaluate a new class of rank-based tests for high-dimensional data that employ robust Mahalanobis interpoint distances, and to demonstrate their practical value in the analysis of EEG signals. This class includes a version based on the MRWCD (minimum regularized weighted covariance determinant) estimator, which enhances the robustness of the Mahalanobis distances by mitigating the influence of outliers.

To illustrate the effectiveness of these tests, EEG data consisting of 1216 variables from 28 patients with Alzheimer’s disease and 146 healthy control individuals were analyzed. The results of multivariate tests reveal significant findings, which are also explored in the context of individual EEG channels and frequencies. Among the approaches tested, rank-based tests using the newly proposed interpoint distances, particularly in combination with the Cucconi test statistic, yield the strongest results. For the comparison between patients and controls, a p-value of 0.004 was obtained, which is below the significance level

α = 0.05

, indicating a statistically significant difference.

脑电图（EEG）信号广泛应用于神经科学研究和生物医学应用，特别是用于患者和对照受试者两个队列之间的比较分析。在脑电图研究中，多变量双样本测试仍未得到充分利用，而多种比较程序往往被误用作为替代，导致误差控制不足。此外，现有的基于秩的测试仅依赖于欧几里得距离，对异常值缺乏鲁棒性。这项工作的目的是开发和评估一类新的基于秩的高维数据测试，该测试采用稳健的马氏点间距离，并展示其在脑电图信号分析中的实用价值。该类包括一个基于MRWCD（最小正则化加权协方差行列式）估计器的版本，它通过减轻异常值的影响来增强马氏距离的鲁棒性。为了说明这些测试的有效性，我们分析了来自28名阿尔茨海默病患者和146名健康对照者的1216个变量的脑电图数据。多变量测试的结果揭示了显著的发现，这些发现也在个体脑电图通道和频率的背景下进行了探讨。在测试的方法中，使用新提出的点间距离的基于等级的测试，特别是与Cucconi测试统计量相结合，产生了最强的结果。患者与对照组比较，p值为0.004，低于显著性水平α=0.05，差异有统计学意义。

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引用次数: 0

A morphometric lung model for evaluating lung aeration at birth 一种用于评估出生时肺通气的肺形态计量学模型

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-10-01 DOI: 10.1016/j.bbe.2025.11.004

Chiara Veneroni , Enrico Conca , Davide Bizzotto , Kenneth Lutchen , Alberto Tosi , Raffaele L. Dellacà

Background

Lung aeration must rapidly develop at birth, but how to promote it without injuring the fragile lung is still unknown. Mathematical models simulating lung mechanics during this transition may help understand the underlying physiological mechanisms and design protective ventilation strategies. This study develops a morphologically-coherent computational lung model incorporating changing physical conditions during the transition from liquid-filled to gas-filled lungs.

Methods

We adapted a 3-D morphological model of the adult airway tree adjusting airway dimensions, lung volume, and lung tissue mechanical properties. Changes in resistance, inertia, and compliance during aeration were modeled by considering the differing properties of fetal fluid versus air. The capillary pressure at the liquid–air interface was computed using Laplace equation. Terminal airway diameters increased with lung volume due to airway-parenchymal interdependence. An integrated circuit simulator solved the entire network in the time domain.

Results

The air volume entering the model at different applied pressures increased exponentially with time. With 30 cmH₂O applied, lung volume reached total capacity after 15 s, matching lung aeration dynamics observed in animal models and human infants. In contrast, after the same time, at 15 cmH₂O, lung volume was slightly above functional residual capacity, and at 10 cmH₂O, it remained below.

Conclusions

The proposed in-silico newborn lung model simulates lung aeration at birth, allowing observation of the airway emptying sequence and the heterogeneity of aeration at each time point. Integrating this model with comprehensive acinar models may aid in defining protective resuscitation ventilation strategies for recruiting the lung minimizing risk of injuries.

出生时肺通气必须迅速发展，但如何在不伤害脆弱的肺的情况下促进肺通气仍是未知的。在这一转变过程中模拟肺力学的数学模型可能有助于理解潜在的生理机制和设计保护性通气策略。本研究开发了一个形态学一致的计算肺模型，该模型包含了从充液肺到充气肺过渡过程中不断变化的物理条件。方法采用成人气道树三维形态模型，调整气道尺寸、肺体积和肺组织力学特性。通过考虑胎液与空气的不同特性，模拟了通气过程中阻力、惯性和顺应性的变化。利用拉普拉斯方程计算了气液界面处的毛细压力。末端气道直径随着肺容量的增加而增加，这是由于气道与肺实质的相互依赖关系。一个集成电路模拟器在时域内求解了整个网络。结果在不同施加压力下进入模型的风量随时间呈指数增长。应用30 cmH2O时，肺容量在15 s后达到总容量，与动物模型和人类婴儿观察到的肺通气动态相匹配。相比之下，相同时间后，在15 cmH2O时，肺容量略高于功能剩余容量，而在10 cmH2O时，肺容量仍低于功能剩余容量。结论所建立的计算机新生儿肺模型模拟了新生儿出生时的肺通气，可以观察气道排空顺序和各时间点通气的异质性。将该模型与全面的腺泡模型相结合，可能有助于确定保护性复苏通气策略，以最大限度地降低肺损伤风险。

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引用次数: 0

Dual-peak cyclic loading for evaluation of lower-limb prostheses 双峰循环载荷对下肢假体的评价

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-10-01 DOI: 10.1016/j.bbe.2025.10.004

Zhaokun Zhang , Wangrui Xu , Hanyu Gan , Chunlei K. Song , Albert J. Shih

Lower-limb prosthesis (LLP) is critical for the mobility and quality of life of amputees. Ensuring the reliability and durability of LLPs is essential to users’ safety, comfort, and mobility. While the current standard (ISO 10328) for the mechanical test of LLPs has served as a foundation, the sinusoidal cyclic loading method used for fatigue testing does not replicate the actual loading conditions on LLPs during a human walking gait. In normal walking, LLPs are subjected to a dual-peak loading condition with two distinct force peaks at the heel-strike and toe-off phases. Such a cyclic and dual-peak dynamic loading pattern on LLP is essential to test the durability of the LLP effectively and reliably. In this study, two simple and effective dual-peak cyclic loading test apparatuses are designed and built to evaluate the durability and functionality of LLPs. Two loading plates are used to contact the heel and toe of the prosthetic foot to simulate the dual-peak heel-strike and toe-off loadings between the foot and the ground. This dual-peak loading on the LLP is controlled and replicated by adjusting the positions of two loading plates and the actuator stroke to change the contact forces. Experimental results show that the proposed testing apparatuses and procedures can emulate the dual-peak axial loading of the LLP during normal walking gait, providing a more accurate testing method of the dynamic loading condition on LLPs than the current ISO standard.

下肢假肢（LLP）对截肢者的活动能力和生活质量至关重要。确保llp的可靠性和耐用性对用户的安全性、舒适性和移动性至关重要。虽然目前的llp力学测试标准（ISO 10328）已经作为基础，但用于疲劳测试的正弦循环加载方法并不能复制人类行走步态时llp的实际加载条件。在正常行走中，llp承受双峰加载条件，在脚跟撞击和脚趾撞击阶段有两个不同的力峰值。这种循环双峰动加载模式对于有效、可靠地测试LLP的耐久性至关重要。本研究设计并搭建了两台简单有效的双峰循环加载试验装置，以评估llp的耐久性和功能性。用两个加载板连接假肢脚的脚跟和脚趾，模拟脚与地面之间的双峰脚跟撞击和脚趾脱落载荷。通过调整两个加载板的位置和执行器行程来改变接触力，可以控制和复制LLP上的双峰载荷。实验结果表明，所提出的测试设备和程序能够模拟LLP在正常行走步态下的双峰轴向载荷，为LLP动态加载状况提供了比现行ISO标准更准确的测试方法。

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引用次数: 0

Design and development of a systematic validation protocol for synthetic melanoma images for responsible use in medical artificial intelligence 设计和开发用于医疗人工智能的合成黑色素瘤图像的系统验证协议

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-09-21 DOI: 10.1016/j.bbe.2025.09.001

Alessio Luschi , Linda Tognetti , Alessandra Cartocci , Elisa Cinotti , Giovanni Rubegni , Laura Calabrese , Martina D’onghia , Martina Dragotto , Elvira Moscarella , Gabriella Brancaccio , Giulia Briatico , Camila Scharf , Dario Buononato , Vittorio Tancredi , Carmen Cantisani , Camilla Chello , Luca Ambrosio , Pietro Scribani Rossi , Marco Virone , Giovanni Pellacani , Ernesto Iadanza

Malignant melanoma is the deadliest form of skin cancer, and artificial intelligence could help address its diagnostic challenges. Generative Adversarial Networks (GANs) can generate synthetic dermoscopic images to augment limited real datasets, but the lack of standardised validation protocols holds back models’ reliability and clinicians’ trust. This study aims to design and develop a systematic validation protocol combining quantitative metrics and qualitative expert assessments to evaluate the realism, fidelity, diversity, and usefulness of synthetic dermoscopic melanoma images. A StyleGAN2 model, designed and trained in a previous study, was selected for its superior quantitative performance and exploited to generate 25 synthetic melanoma images, matched with 25 real images. A panel of 17 dermoscopists assessed the images using a 7-point Likert scale, across multiple qualitative attributes (real vs. synthetic, skin texture, visual realism, and confidence) and pattern analysis. Accuracy, sensitivity, specificity, Fleiss’ Kappa, and Krippendorff’s Alpha were calculated to analyse inter-rater agreement and evaluation outcomes. Accuracy in real vs synthetic images classification was moderate (64 %), with sensitivity at 73 % and specificity at 56 %, with poor inter-rater concordance over qualitative attributes. Synthetic images obtained superior scores in medium visual and overall realism, and confidence level, while the frequency of recognition of pigment network-patterns was comparable with real images. The proposed holistic validation protocol can effectively estimate the quality level of synthetic dermoscopic images, regardless of the architecture of the model used for generation, offering an objective and reliable evaluation tool, as qualitative evaluations remain crucial to ensure their safe deployment in clinical settings.

恶性黑色素瘤是最致命的皮肤癌，人工智能可以帮助解决其诊断挑战。生成对抗网络（GANs）可以生成合成的皮肤镜图像来增强有限的真实数据集，但缺乏标准化的验证协议阻碍了模型的可靠性和临床医生的信任。本研究旨在设计和开发一种结合定量指标和定性专家评估的系统验证方案，以评估合成皮肤镜下黑色素瘤图像的真实感、保真度、多样性和有用性。在之前的研究中设计和训练的StyleGAN2模型因其优越的定量性能而被选中，并利用它生成25张合成黑色素瘤图像，与25张真实图像相匹配。一个由17名皮肤科医生组成的小组使用7分李克特量表评估图像，包括多个定性属性（真实与合成、皮肤纹理、视觉真实感和信心）和模式分析。计算准确性、敏感性、特异性、Fleiss Kappa和Krippendorff Alpha来分析评分者之间的一致性和评估结果。真实图像与合成图像分类的准确率为中等（64%），灵敏度为73%，特异性为56%，定性属性间一致性较差。合成图像在中等视觉和整体真实感以及置信度方面得分较高，而对色素网络模式的识别频率与真实图像相当。所提出的整体验证方案可以有效地估计合成皮肤镜图像的质量水平，而不考虑用于生成的模型的架构，提供客观可靠的评估工具，因为定性评估对于确保其在临床环境中的安全部署至关重要。

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引用次数: 0

A wireless, implantable, dual-channel phrenic nerve stimulator for diaphragm pacing using electromagnetic resonance coupling 一种无线、可植入、双通道膈神经刺激器，用于使用电磁共振耦合的膈神经起搏

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-08-30 DOI: 10.1016/j.bbe.2025.08.007

Xiaoyu Gu , Wei Zhong , Yan Shi , Meng Xu , Zhaohui Tong , Yixuan Wang

Objectives

Implantable diaphragm pacing (DP) system can effectively restore patients’ breathing.

Conventional diaphragm pacemakers have some practical limitations, such as transmission stability and high price. This study proposes an innovative, wirelessly powered dual-channel and inexpensive DP system to overcome some of these constraints.

Methods

The system realizes wireless power supply based on electromagnetic resonance coupling to improve stability. It comprised an external controller, two off-body transmitters and two in-vivo rectifier-integrated receivers. PCB spiral coils are used for energy transmission in wireless systems to ensure system stability and convenient processing. Receiver encapsulated with biocompatible PDMS convert received power into electrical stimulation energy. Stimulation waveform, multi-media environment and animal experimental tests were conducted to validate system’s performance. Specific absorption rate (SAR) in human tissue was calculated to confirm safety of implantation.

Results

Electrical stimulation parameters of the proposed DP system can be precisely adjusted. The stimulation amplitude range is 3–12 V with 0.1 V step resolution. Pulse width and frequency are adjustable from 100-300 µs and 10–100 Hz respectively. The breathing cycle and inhalation time can also be set individually. Wireless energy transmission has wide transmission distance (＞14 mm), good anti-offset capability (horizontal offset＞8mm) and implantation safety (SAR＜1.6 W/kg). Further time series of stimulation signals issued by the two channels are synchronized. The developed system effectively realizes respiratory response of animals to bilateral phrenic nerve stimulation with 17 mm wireless energy transmission distance and implantation of two receivers in vivo.

Conclusion

Our work provides a new optimization scheme for the design of implantable diaphragm pacemaker.

目的植入式膈肌起搏（DP）系统能有效恢复患者的呼吸。传统的膜片起搏器在实际应用中存在传输不稳定、价格昂贵等局限性。本研究提出了一种创新的、无线供电的双通道和廉价的DP系统来克服这些限制。方法实现基于电磁谐振耦合的无线供电，提高系统的稳定性。它包括一个外部控制器，两个离体发射器和两个体内整流集成接收器。无线系统中的能量传输采用PCB螺旋线圈，保证了系统的稳定性和处理的便捷性。用生物相容性PDMS封装的接收器将接收的功率转换为电刺激能量。通过刺激波形、多媒体环境和动物实验验证了系统的性能。计算人体组织的比吸收率（SAR）以确认植入的安全性。结果所提出的DP系统的电刺激参数可精确调节。刺激幅度范围为3 ~ 12v，步进分辨率为0.1 V。脉冲宽度和频率分别在100-300µs和10-100 Hz范围内可调。呼吸周期和吸入时间也可以单独设置。无线能量传输具有传输距离宽（> 14mm）、抗偏移能力好（水平偏移>8mm）和植入安全性（SAR<1.6 W/kg）等优点。两个通道发出的刺激信号的进一步时间序列是同步的。该系统通过17毫米无线能量传输距离，在体内植入两个接收器，有效地实现了动物对双侧膈神经刺激的呼吸反应。结论本工作为植入式隔膜起搏器的优化设计提供了一种新的方案。

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引用次数: 0

TRI-based heart rate variability parameterisation: advancing autonomic dysfunction assessment in diabetes and aging—A cross-sectional observational study 基于三自由度的心率变异性参数化：推进糖尿病和衰老的自主神经功能障碍评估——一项横断面观察研究

IF 6.6 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-08-29 DOI: 10.1016/j.bbe.2025.08.006

Shanglin Yang , Yuyang Lin , Xuwei Liao , Jianjung Chen , Hsientsai Wu

This cross-sectional observational study introduces the T-R interval (TRI), a novel electrocardiographic parameter designed to improve heart rate variability (HRV) assessment in ageing and diabetic populations. Defined as the R-R interval (RRI) minus the heart rate-corrected RT interval (RTc), TRI incorporates both depolarisation and repolarisation phases of the cardiac cycle, thereby offering deeper insights into autonomic function. A total of 126 participants, including 58 individuals with type 2 diabetes mellitus and 68 healthy controls, were assessed using conventional HRV indices. These included the low-to-high frequency power ratio (LHR), the short-to-long variability ratio (SSR), and the baroreflex entropy index (BEI), all of which were calculated from both RRI and TRI data. TRI-based indices demonstrated superior sensitivity in detecting autonomic dysfunction. Significant group differences were observed for TRI-derived MSE_LS (mean difference = 0.205, 95 % CI: 0.093–0.317, p = 0.036), SSR (mean difference = − 0.083, 95 % CI: −0.136–−0.029, p = 0.051), and BEI (mean difference = 0.205, 95 % CI: 0.093–0.318, p = 0.002), while their RRI-based equivalents did not reach statistical significance. ROC curve analysis showed improvements in the area under the curve (AUC) when TRI was used as the input parameter, with gains of 5.9 % for MSE_LS, 10.6 %for SSR, and 6.1 % for BEI. Logistic regression further identified TRI-based BEI as a protective factor against new-onset T2DM (OR = 0.058; 95 % CI: 0.009–0.378; p = 0.003). These findings suggest that TRI improves the diagnostic performance of HRV analysis and may support earlier detection of autonomic dysfunction, especially in clinical and wearable monitoring settings.

这项横断面观察性研究引入了T-R间隔（TRI），这是一种新的心电图参数，旨在改善老年人和糖尿病人群的心率变异性（HRV）评估。TRI被定义为R-R间期（RRI）减去心率校正后的RT间期（RTc），它结合了心脏周期的去极化和复极化阶段，从而对自主神经功能提供了更深入的了解。共有126名参与者，包括58名2型糖尿病患者和68名健康对照者，使用常规HRV指数进行评估。其中低高频功率比（LHR）、短长变异性比（SSR）和气压反射熵指数（BEI）均由RRI和TRI数据计算得到。基于tri的指数在检测自主神经功能障碍方面表现出更高的灵敏度。tri衍生的MSELS（平均差异= 0.205,95% CI: 0.093-0.317, p = 0.036）、SSR（平均差异= - 0.083,95% CI: - 0.136 - - 0.029, p = 0.051）和BEI（平均差异= 0.205,95% CI: 0.093-0.318, p = 0.002）组间差异显著，而基于rri的等效性差异无统计学意义。ROC曲线分析显示，以TRI作为输入参数时，MSELS、SSR和BEI的曲线下面积（AUC）分别增加了5.9%、10.6%和6.1%。Logistic回归进一步确定基于三因素的BEI是预防新发T2DM的保护因素（OR = 0.058; 95% CI: 0.009-0.378; p = 0.003）。这些发现表明，TRI提高了HRV分析的诊断性能，并可能支持自主神经功能障碍的早期检测，特别是在临床和可穿戴监测设置中。

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引用次数: 0

Lumbar intervertebral disc biomechanics: Geometry and collagen fiber orientation configurations effects 腰椎间盘生物力学：几何和胶原纤维取向构型的影响

IF 5.3 2区医学 Q1 ENGINEERING, BIOMEDICAL

Biocybernetics and Biomedical Engineering

Pub Date : 2025-07-01 DOI: 10.1016/j.bbe.2025.07.003

Zhongwei Sun , Jiabao Pan , Weishi Liang , Changwen Mi , Peng Yin

This study proposes a probabilistic biphasic-swelling parameterized finite element framework, with the aim of which is to systematically evaluate the impact of lumbar intervertebral disc (L-IVD) geometry and annulus fibrosus collagen fiber configuration on multi-axial biomechanical behavior. Thirty anatomical L-IVD geometric sets were sampled via Latin hypercube sampling of clinical anatomical variations. Three annulus fibrosus layer-wise fiber configurations were implemented: Constant

30^{\circ}

, Circumferential variation (

25^{\circ} - - 45^{\circ}

), and Circumferential-radial variation (

23^{\circ} - - 50^{\circ}

). Consequently, the construction of three groups, comprising a total of ninety biphasic L-IVD finite element models, was undertaken. Five loading protocols were then simulated to reveal the critical dependencies of L-IVD biomechanical behavior. A statistical comparative analysis was performed to evaluate the influence of disc geometries and orientation strategies. The findings demonstrated that fiber orientation configuration exerts a substantial influence on swelling responses, compression stiffness, and flexion stiffness (

p < . 050

). Disc height exhibited strong inverse correlations with intradiscal pressure (

r < - 0.80

,

p < . 001

) and compression stiffness (

r < - 0.85

,

p < . 001

). Anterior-posterior length emerged as the primary predictor of sagittal stiffness (flexion:

r > 0.70

; extension:

r > 0.75

) and torsional resistance (

r > 0.50

), linked to altered moment arm mechanics. The nucleus pulposus volume ratio moderately affected intradiscal pressure (

r > 0.30

,

p < . 05

) but showed negligible impact on segmental stiffness. This parametric modelling framework facilitates systematic investigation of L-IVD biomechanics across anatomical variations. Additionally, these findings advocate for microstructure-informed computational models to optimize personalized implant designs and biomechanical assessments.

本研究提出了一个概率双相肿胀参数化有限元框架，旨在系统评估腰椎间盘（L-IVD）几何形状和纤维环胶原纤维结构对多轴生物力学行为的影响。通过临床解剖变异的拉丁超立方体采样，对30个解剖L-IVD几何集进行采样。纤维环按纤维层的排列有三种：恒定的30°、圆周变化（25°- 45°）和圆周径向变化（23°- 50°）。因此，进行了三组，包括共90个双相L-IVD有限元模型的构建。然后模拟五种加载方案，以揭示L-IVD生物力学行为的关键依赖关系。我们进行了统计比较分析，以评估椎间盘几何形状和定位策略的影响。研究结果表明，纤维取向结构对膨胀响应、压缩刚度和弯曲刚度有实质性影响（p< 0.050）。椎间盘高度与椎间盘内压力（r< - 0.80, p<.001）和压缩刚度（r< - 0.85, p<.001）呈强烈的负相关。前后长度是矢状位刚度的主要预测因子(屈曲：r>；0.70；延伸：r>；0.75)和扭转阻力（r>0.50），与改变的力臂力学有关。髓核体积比适度影响椎间盘内压力（r>0.30, p< 0.05），但对节段刚度的影响可以忽略不计。这种参数化建模框架有助于系统地研究跨解剖变异的L-IVD生物力学。此外，这些发现提倡微观结构的计算模型，以优化个性化的种植体设计和生物力学评估。

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引用次数: 0