Biomedical Engineering Letters最新文献

{"title":"fNIRS-based cortical activation during swallowing-related tasks: implications for dysphagia rehabilitation-a scoping review.","authors":"Na-Kyoung Hwang, Gihyoun Lee, Ji-Su Park","doi":"10.1007/s13534-026-00601-z","DOIUrl":"10.1007/s13534-026-00601-z","url":null,"abstract":"<p><p>Swallowing is a complex sensorimotor function requiring coordinated cortical and subcortical control and is frequently impaired in neurological disorders. Functional near-infrared spectroscopy (fNIRS) has emerged as a promising non-invasive neuroimaging modality for investigating swallowing-related cortical activity; however, its application in dysphagia research remains methodologically heterogeneous. This scoping review aimed to map existing evidence on the use of fNIRS in swallowing and dysphagia rehabilitation and to identify prevailing concepts and knowledge gaps. The review followed the Joanna Briggs Institute methodology and PRISMA-ScR guidelines. Electronic searches of MEDLINE, Embase, Scopus, and Web of Science were conducted from database inception to September 2025. Studies involving adult participants and task- or intervention-based fNIRS assessment of swallowing-related cortical activity were included. Twenty-one studies involving healthy adults and patients with dysphagia met the inclusion criteria. Swallowing consistently activated a distributed fronto-sensorimotor cortical network, with activation patterns modulated by sensory stimulation, motor demands, and neuromodulation. Considerable heterogeneity was observed in study design, task paradigms, optode placement, and analytical approaches, limiting cross-study comparability. Overall, fNIRS demonstrates feasibility and sensitivity for assessing swallowing-related cortical activity in both experimental and clinical contexts. However, methodological variability and the limited inclusion of clinical populations restrict the interpretation and generalizability of current findings. The development of standardized protocols and clinically relevant outcome measures will be essential for translating fNIRS into routine dysphagia assessment and rehabilitation.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1197-1217"},"PeriodicalIF":3.4,"publicationDate":"2026-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615263/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Power-free passive preconcentration cassette in lateral flow assays for enhanced sensitivity.","authors":"Cheonjung Kim, Dohwan Lee, Na Eun Lee, Kang Hyeon Kim, Ho Seung Song, Yina Jeong, Jeong Hoon Lee, Yong Kyoung Yoo","doi":"10.1007/s13534-026-00598-5","DOIUrl":"10.1007/s13534-026-00598-5","url":null,"abstract":"<p><p>Lateral flow assays (LFAs) are widely used for point-of-care diagnostics because of their simplicity and affordability. However, their sensitivity remains insufficient for detecting low-abundance biomarkers, which limits their applicability in early disease detection and in resource-constrained environments. This study investigates whether a power-free passive preconcentration cassette (PPC) can enhance LFA sensitivity without compromising usability. A PPC that integrates seamlessly with commercial LFA housings was developed to enhance detection sensitivity without compromising usability. The PPC employs a Nafion-coated pin array to enable ion-selective transport during capillary-driven flow, creating a localized enrichment zone. Geometric optimization of the pin-array architecture revealed a hybrid design that balances ionic polarization with flow uniformity. When applied to PPC-LFAs for influenza A and hepatitis C detection, the platform achieved approximately a fourfold improvement in sensitivity while maintaining specificity and stable fluidic performance. This ion-selective, self-powered preconcentration strategy provides a broadly applicable, instrument-free means of improving LFA sensitivity, making it especially suitable for decentralized and self-administered diagnostic applications.</p><p><strong>Supplementary information: </strong>The online version contains supplementary material available at https://doi.org/10.1007/s13534-026-00598-5.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1407-1417"},"PeriodicalIF":3.4,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615227/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064875","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three-dimensional microelectrode arrays for <i>in vitro</i> neuronal network models: structural designs, manufacturing approaches, and future perspectives.","authors":"Dongjo Yoon, Yoonkey Nam","doi":"10.1007/s13534-026-00610-y","DOIUrl":"10.1007/s13534-026-00610-y","url":null,"abstract":"<p><p>Three-dimensional (3D) microelectrode arrays (MEAs) have been actively developed to enable electrophysiological recording from <i>in vitro</i> 3D neuronal network models, which have attracted considerable research interest in recent years. These devices overcome the fundamental limitation of conventional planar MEAs, in which microelectrodes are confined to a single plane, by distributing microelectrodes throughout 3D space. This enables direct access to neurons throughout the tissue, allowing precise analysis of neural activity in 3D space across the neuronal network. Depending on the strategy used to position microelectrodes in 3D space, current 3D MEAs have been developed in a variety of structural configurations, including probe-, tip-, planar mesh-, 3D mesh-, curved surface-, stretchable mesh-, and wrapping-architectures. These structurally diverse devices have primarily been fabricated using photolithography-based microfabrication processes, while more recently, 3D printing technology has been adopted to improve structural design freedom for complex 3D structures. In this review, we discuss the structural diversity and fabrication strategies of 3D MEAs for <i>in vitro</i> 3D neuronal network models, examine recent advances and current limitations, and outline future directions for the field.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1183-1196"},"PeriodicalIF":3.4,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615228/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149065024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Brain ultrasound imaging through sonolucent cranial implants: a review and perspective.","authors":"Junhee Lee, Heechul Yoon, Jae Song, Sua Bae","doi":"10.1007/s13534-026-00593-w","DOIUrl":"https://doi.org/10.1007/s13534-026-00593-w","url":null,"abstract":"<p><p>Brain ultrasonography has historically been limited by strong skull-induced attenuation and phase aberration, restricting its clinical application to narrow acoustic windows such as the temporal bone. The emergence of sonolucent cranial implants used in cranioplasty has introduced a new paradigm in which the implant itself serves as a postoperative acoustic window. Over the past decade, clinical studies have demonstrated the feasibility of transimplant (or transcranioplasty) B-mode imaging, Doppler-based vascular assessment, and contrast-enhanced ultrasound in patients with sonolucent implants. Beyond currently validated modalities, transimplant access broadens the scope of ultrasound applications in adult neuroimaging, enabling the extension of advanced techniques such as ultrasound localization microscopy, shear-wave elastography, quantitative ultrasound, and therapeutic ultrasound. Although sonolucent implants substantially reduce attenuation relative to the native skull, incomplete acoustic matching with brain tissue still introduces propagation-related distortions, and technical challenges remain. We summarize current applications of transimplant imaging, explore potential future modalities, and examine key technical challenges-including geometric coupling and implant-induced acoustic effects-along with future engineering strategies. By integrating clinical evidence with acoustic principles and technical considerations, this review provides an overview of the opportunities and challenges of brain ultrasound imaging through cranial implants.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 4","pages":"817-835"},"PeriodicalIF":3.4,"publicationDate":"2026-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13476406/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148762282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digital twin for neurological conditions: a systematic scoping review.","authors":"Bo-Young Youn, Soohyuk Park, Dahyun Song, Ki Chang Nam","doi":"10.1007/s13534-026-00605-9","DOIUrl":"10.1007/s13534-026-00605-9","url":null,"abstract":"<p><p>Digital twin technology has emerged as a promising approach for advancing precision medicine in complex diseases, particularly in neurology. This scoping review aimed to systematically map the current literature on digital twin applications in neurological conditions, focusing on study characteristics, modeling approaches, data sources, and clinical applications. A comprehensive search across six databases from inception to February 2026 identified 36 studies that met the inclusion criteria. The findings demonstrated a rapid increase in publications since 2023, with Alzheimer's disease (<i>n</i> = 14) and stroke (<i>n</i> = 12) representing the most frequently studied conditions. Data-driven and machine learning-based models were the most common approaches, followed by mechanistic and hybrid models. Major application domains included clinical trial optimization, disease progression modeling, risk prediction, and personalized treatment. However, most studies were proof-of-concept or retrospective in design, with limited external validation and no randomized controlled trials identified. Additionally, many models lacked continuous real-time data integration, indicating that few met the criteria of fully dynamic digital twins. These findings suggest that while digital twins hold substantial potential to transform precision neurology, significant challenges remain in terms of methodological rigor, standardization, and clinical translation. Future research should prioritize prospective validation, integration of multimodal real-world data, and the development of standardized frameworks to support safe and effective implementation.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1219-1242"},"PeriodicalIF":3.4,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615232/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trends in neuroprosthetic technologies to restore sensations.","authors":"Byungwook Park, Woojae Butterworth, Nayeong Lee, Sohee Kim","doi":"10.1007/s13534-026-00603-x","DOIUrl":"10.1007/s13534-026-00603-x","url":null,"abstract":"<p><p>The loss of sensory function significantly reduces the ability to perform daily activities and lowers quality of life. Accordingly, the artificial replacement or support of impaired sensory function has become one of the main objectives of neural engineering and neuroprosthetics. This review systematically organizes auditory, visual, and somatosensory restoration technologies by target organ-from peripheral sensory organs to the central nervous system-and provides a comprehensive overview of the achievements and limitations of each approach. Auditory restoration includes cochlear, brainstem, and auditory cortex approaches; visual restoration includes retinal, optic nerve, and visual cortex approaches; and somatosensory restoration includes somatosensory cortex and peripheral nerve approaches. Although neuroprosthetics-based sensory restoration technologies have achieved considerable progress, the sensations currently restored remain far from natural perception. This review discusses future directions to address these limitations, focusing on higher-density electrodes, device and system optimization, decoding-based biomimetic stimulation, and personalized stimulation strategies. Ultimately, these advances may enable more natural sensation and improve the quality of life of patients with sensory impairments.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1143-1164"},"PeriodicalIF":3.4,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615277/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determinants of spatial resolution in retinal prostheses: understanding the gap between geometry and vision.","authors":"Seoyoung Hwang, Hee Soo Jeong, Sang Beom Jun","doi":"10.1007/s13534-026-00604-w","DOIUrl":"10.1007/s13534-026-00604-w","url":null,"abstract":"<p><p>Retinal prosthetic systems have emerged as a promising technology for restoring partial vision in patients with severe photoreceptor degeneration. Over the past two decades, development in epiretinal, subretinal, and suprachoroidal devices has progressed substantially, with several representative platforms demonstrating the feasibility of restoring light perception, object localization, motion discrimination, and limited-form vision in clinical settings. Despite these advances, the visual acuity achieved by existing retinal prostheses remains markedly lower than predictions based on device geometry alone. Particularly, a persistent gap exists between the theoretical spatial resolution implied by electrode or pixel spacing and clinically reported visual performance. This review examines the major factors limiting effective spatial resolution in retinal prosthetic systems, with particular emphasis on the resolution gap. Collectively, available evidence indicates that while electrode spacing may be considered a critical determinant of theoretical resolution, it does not represent a direct surrogate for clinical visual acuity. Consequently, improving prosthetic vision requires denser arrays alongside selective neural recruitment, more stable electrode-retina coupling, and stimulation strategies that optimize functionally meaningful percepts. Elucidating the resolution gap and its underlying determinants will be essential for developing next-generation retinal prosthetic systems that provide more effective visual restoration.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1165-1181"},"PeriodicalIF":3.4,"publicationDate":"2026-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615219/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AI-integrated closed-loop brain-machine interfaces using soft bioelectronics.","authors":"Seohyeon Kim, Daeun Kim, Donghee Son","doi":"10.1007/s13534-026-00606-8","DOIUrl":"10.1007/s13534-026-00606-8","url":null,"abstract":"<p><p>Social and clinical demands for restoring lost neurological functions are rising due to the increasing prevalence of neurodegenerative diseases, paralysis, and aging populations. In response, brain-machine interfaces (BMIs) have emerged as a promising technology, with recent advances demonstrating substantial progress toward clinical translation. These advances are exemplified by high-channel neural interfaces and fully implantable systems developed by both academic and industrial efforts, including recent industry-led fully implantable BMIs. Despite these advances, current BMI systems still face critical limitations across multiple aspects. Mechanical mismatch between rigid electrodes and soft neural tissue at the material level induces chronic inflammation and progressive signal degradation, ultimately compromising long-term performance. This limitation extends to the device level, where insufficient structural adaptability hinders stable interfacing under dynamic physiological conditions. Building upon these challenges, conventional open-loop systems at the system level fail to account for temporal and inter-individual variability, thereby restricting the realization of truly personalized neuromodulation. Here, we review recent progress in addressing these challenges through the integration of soft and adaptive materials, which enable mechanically compliant, minimally invasive, and structurally adaptive neural interfaces capable of maintaining stable interactions with brain tissue over extended periods. Importantly, these material and device-level innovations are increasingly related to system-level advancements, including closed-loop systems enabling real-time feedback and AI-assisted decoding techniques. Advanced AI technique requires large volumes of high-quality neural data collected from high density of electrode arrays to achieve reliable decoding and personalized neuromodulation. In this context, tissue modulus matching and chronically stable soft interfaces play a critical role in reducing signal degradation and long-term data reliability. Such integration between material, device and system allows continuous monitoring and dynamic modulation of neural activity. This enables more precise, personalized, and context-aware brain-machine interactions, leading to advanced AI-based soft closed-loop bioelectronics for BMIs.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1117-1141"},"PeriodicalIF":3.4,"publicationDate":"2026-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615258/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced non-invasive brain neuromodulation: a comprehensive review of electric, magnetic, ultrasonic, and optical modalities.","authors":"Kyungsik Eom, Kyung Min Byun","doi":"10.1007/s13534-026-00600-0","DOIUrl":"10.1007/s13534-026-00600-0","url":null,"abstract":"<p><p>Non-invasive brain neuromodulation has emerged as a transformative frontier in neuroscience and clinical medicine, offering the ability to modulate neuronal excitability and network connectivity without the risks associated with surgical intervention. As the neurological and psychiatric disorders increase, the development of non-invasive technologies has accelerated and moved from basic physiological exploration to advanced therapeutic applications. This review provides a systematic analysis of the four non-invasive modalities of transcranial magnetic stimulation, transcranial electrical stimulation, transcranial ultrasound stimulation, and transcranial photobiomodulation. This review covers the principles, methods, clinical applications, and dosimetry of the four modalities as well as their current trends toward multi-modal and closed-loop systems. By integrating neuromodulation with real-time neuroimaging or electrophysiological monitoring, we can deliver personalized and state-dependent stimulation that adapts to the individual brain state. We also address the integration of deep learning and artificial intelligence in optimizing stimulation parameters to improve therapeutic efficacy. By synthesizing recent breakthroughs across diverse modalities, this review can provide a strategy for the next-generation brain neuromodulation, emphasizing higher precision, deeper penetration, and personalized clinical interventions.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1095-1116"},"PeriodicalIF":3.4,"publicationDate":"2026-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615243/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing volitional electromyographic control strategies: from proportional mapping to muscle modeling and reflex augmentation.","authors":"Matthias Voß, Rodrigo J Velasco-Guillen, Philipp Beckerle","doi":"10.1007/s13534-026-00594-9","DOIUrl":"10.1007/s13534-026-00594-9","url":null,"abstract":"<p><p>To advance intuitive volitional control for lower-limb prostheses, this study compares three torque control architectures based on electromyography (EMG) - including a novel reflex-augmented approach - using a virtual balance task. The goal is to determine whether muscle-model-based control improves performance and reduces user load relative to proportional EMG control, and whether incorporating simulated stretch reflexes further enhances results. Sixteen participants performed a virtual balancing task using EMG signals from antagonist lower-leg muscles to control an inverted pendulum subjected to perturbations. Four controllers were tested in randomized order: proportional, model-based, and two reflex-augmented variants differing in reflex gain. The model-based controller employed paired Hill-type muscle models; reflex variants additionally injected velocity-dependent stretch reflex feedback. User load was captured alongside control performance. While all participants successfully used all controllers, the model-based controller consistently enabled more stable and less effortful control than proportional EMG control. Reflex augmentation altered pendulum dynamics and showed slight performance tendencies in favor of the weaker reflex gain but did not yield clear or consistent benefits across participants compared with the model-based controller alone. Overall, incorporating muscle mechanics into EMG-based control substantially improves intuitive torque regulation over simple proportional mapping. While reflex augmentation showed promising potential, its current formulation did not provide reliable added value, indicating a need for refined reflex modeling and parameter tuning for future volitional prosthesis control applications.</p>","PeriodicalId":46898,"journal":{"name":"Biomedical Engineering Letters","volume":"16 5","pages":"1319-1331"},"PeriodicalIF":3.4,"publicationDate":"2026-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13615268/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149064931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}