BioMedical Engineering OnLine最新文献

Background: Corneal refractive laser surgery is widely used to correct myopia and astigmatism due to its safety and effectiveness. However, postoperative changes in corneal biomechanics, such as corneal ectasia, can occur, necessitating a deeper understanding of these changes. Finite Element Analysis has shown promise in predicting surgical outcomes based on corneal biomechanics. Devices like the Ocular Response Analyser (ORA) and Corvis ST provide noninvasive ways to measure corneal biomechanics, aiding in the assessment of corneal behavior post-surgery. Young's modulus and tangent modulus are crucial parameters for describing corneal elasticity, but there is limited data on the changes in tangent modulus following Femtosecond Laser-Assisted LASIK (FS-LASIK) in humans. This study aimed to investigate the effect of FS-LASIK on the corneal tangent modulus using a novel corneal indentation device (CID). The study sought to explore changes in corneal tangent modulus after FS-LASIK, taking into account central corneal thickness (CCT) and corneal radius, to enhance our understanding of the biomechanical changes induced by this surgical procedure.

Results: Sixty-six patients (66 eyes) underwent FS-LASIK, resulting in significant changes in CCT, corneal radius, and Goldmann intraocular pressure (GAT IOP) 6 months post-surgery (△CCT = - 88 ± 31 µm, △corneal radius = 0.81 ± 0.30 mm, △GAT IOP = - 3.2 ± 2.4 mmHg, p < 0.001) 6 months after surgery. However, corneal stiffness did not significantly change (△ = - 0.002 ± 0.011, p < 0.2). The corneal tangent modulus showed a significant increase post-surgery (△ = 0.263 ± 0.146, p < 0.001), exhibiting a negative correlation with CCT (r = - 0.68, P < 0.001) and a positive correlation with corneal radius (r = 0.71, P < 0.001). For each 1 mm increase in corneal radius, there was a 0.23 MPa increase in corneal modulus, and for every 100 µm reduction in corneal thickness, there was a 0.14 MPa increase in corneal modulus.

Conclusions: The corneal tangent modulus, influenced by corneal radius and CCT, increased significantly following FS-LASIK. This study highlights the biomechanical changes induced by FS-LASIK, with implications for understanding corneal behavior post-surgery and its potential impact on patient outcomes.

Background: Rhythm-based rehabilitation interventions are gaining attention and measuring their effects is critical. With more clinical care and research being conducted online, it is important to determine the feasibility of measuring rhythm abilities online. However, some tools used to measure rhythm abilities, in particular the beat alignment test (BAT), have not been validated for online delivery. This study aims to determine the feasibility, reliability, and learning effects for online delivery of the BAT in adults with and without stroke.

Methods: Neurotypical adults and adults with chronic stroke completed the BAT online three times, with testing sessions separated by 2 to 4 days. The BAT includes a perception task (identifying whether tones overlayed on music matched the beat of the music) and a production task (tapping to the beat of music). Feasibility was evaluated with completion rates, technical challenges and resolutions, participant experience via exit questionnaire, and test duration. Reliability was measured using inter-class correlations and standard error of measurement, and learning effects were determined using a repeated-measures ANOVA.

Results: Thirty-nine neurotypical adults and 23 adults with stroke participated in this study. More a priori feasibility criteria for the online BAT were met with neurotypical adults than people with stroke. Most components of the online BAT were considered reliable based on an ICC = 0.60 cut-off, except for perception in the neurotypical group, and production asynchrony in the stroke group. There was notable variability in performance, but no learning effects in either group.

Conclusions: Online administration of the BAT is more feasible for neurotypical adults than people with stroke. Challenges with online administration for people with stroke may be partly related to the delivery platform. The BAT is a reliable tool with no learning effects and therefore is a promising way to assess for rhythm abilities online with careful consideration of user interface for people with stroke.

Purpose: This study introduces a transferable alignment-free adaptive joint torque measurement (AFAJTM) system designed to resolve inconsistencies in torque measurements caused by misalignment between dynamometer and joint rotational axes, improving accuracy and reliability in joint torque assessment.

Method: This study presents the design and control methodology of an alignment free adaptive joint torque measurement system. An elbow joint torque measurement device (EJTMD) was developed, and its torque consistency and repeatability were evaluated at various misalignment positions using a joint simulation model. Clinical experiments compared torque measurements between the EJTMD and a traditional standard dynamometer during maximum voluntary contraction (MVC) tests at different misalignment positions.

Result: The simulation test results demonstrate that the AFAJTM system can achieve high-precision torque measurements, with measurement errors controlled within ± 0.5 Nm at various misalignment positions. Clinical experiment data show that the EJTMD exhibits high consistency in torque measurements compared to the traditional standard dynamometer across five different misalignment positions, with strong repeatability and reliability.

Conclusion: The AFAJTM system provides a novel solution for joint torque measurement under human-machine axis misalignment conditions, a solution that eliminates the need for axis alignment, effectively overcoming the limitations of traditional measurement devices. This system can be widely applied in various devices that require joint torque measurement, demonstrating excellent adaptability and high-precision measurement capabilities.

This paper reviews the recent advancements in the application of deep learning combined with electrocardiography (ECG) within the domain of cardiovascular diseases, systematically examining 198 high-quality publications. Through meticulous categorization and hierarchical segmentation, it provides an exhaustive depiction of the current landscape across various cardiovascular ailments. Our study aspires to furnish interested readers with a comprehensive guide, thereby igniting enthusiasm for further, in-depth exploration and research in this realm.

Background: Established assessment scales used for Parkinson's disease (PD) have several limitations in tracking symptom progression and fluctuation. Both research and commercial-grade wearables show potential in improving these assessments. However, it is not known whether pervasive and affordable devices can deliver reliable data, suitable for designing open-source unobtrusive around-the-clock assessments. Our aim is to investigate the usefulness of the research-grade wristband Empatica E4, commercial-grade smartwatch Fitbit Sense, and the Oura ring, for PD research.

Method: The study included participants with PD (N = 15) and neurologically healthy controls (N = 16). Data were collected using established assessment scales (Movement Disorders Society Unified Parkinson's Disease Rating Scale, Montreal Cognitive Assessment, REM Sleep Behavior Disorder Screening Questionnaire, Hoehn and Yahr Stage), self-reported diary (activities, symptoms, sleep, medication times), and 2-week digital data from the three devices collected simultaneously. The analyses comprised three steps: preparation (device characteristics assessment, data extraction and preprocessing), processing (data structuring and visualization, cross-correlation analysis, diary comparison, uptime calculation), and evaluation (usability, availability, statistical analyses).

Results: We found large variation in data characteristics and unsatisfactory cross-correlation. Due to output incongruences, only heart rate and movement could be assessed across devices. Empatica E4 and Fitbit Sense outperformed Oura in reflecting self-reported activities. Results show a weak output correlation and significant differences. The uptime was good, but Oura did not record heart rate and movement concomitantly. We also found variation in terms of access to raw data, sampling rate and level of device-native processing, ease of use, retrieval of data, and design. We graded the system usability of Fitbit Sense as good, Empatica E4 as poor, with Oura in the middle.

Conclusions: In this study we identified a set of characteristics necessary for PD research: ease of handling, cleaning, data retrieval, access to raw data, score calculation transparency, long battery life, sufficient storage, higher sampling frequencies, software and hardware reliability, transparency. The three analyzed devices are not interchangeable and, based on data features, none were deemed optimal for PD research, but they all have the potential to provide suitable specifications in future iterations.

Background: Vibrotactile input is a useful sensory cue for individuals with Parkinson's Disease (PD) to overcome freezing of gait (FoG). For this input to serve as a cue, its accurate perception is required. This needs the input to be delivered at an anatomical location where it can be perceived. This is particularly true for individuals with PD whose tactile perception differs from that of healthy individuals. Literature indicates choice of various anatomical locations e.g., Finger, Wrist, Thigh, Shin, Calf, Ankle, Achilles Tendon, Heel and torso for the application of vibrotactile stimulation. Though studies have focused on the comparison of the vibrotactile perception (based on feedback) at various anatomical locations, yet these have involved only healthy individuals. However, such exploration remains as majorly untouched for individuals with PD.

Methods: To bridge this gap, here we have conducted a study using our vibrotactile stimulation system while involving twenty-one individuals with PD to understand the choice of anatomical location with regard to vibrotactile perception. In addition, our study involved twenty-one age-matched healthy individuals to understand possible differences if any in vibrotactile perception between the two groups of participants.

Results: Our results showed that for the healthy participants, both 'Wrist' and 'Thigh' were equally strong anatomical locations with regard to vibrotactile perception that were correctly identified 100% of the time closely followed by 'Finger' for which the correct identification was 98% of the time with correct identification for all these three locations being statistically (p < 0.05) higher than the other locations. In contrast, for individuals with PD, the 'Thigh' emerged as a strong candidate anatomical location with regard to vibrotactile perception even for those with severity of symptoms (based on clinical measure) that was correctly identified 96% of the time followed by 'Wrist' for which the correct identification was 92% of the time with the correct identification for only the 'Thigh' being statistically (p < 0.05) higher than all the other locations (except 'Wrist').

Conclusion: This finding is clinically significant in deciding the right anatomical location to offer vibrotactile cues for it to be correctly perceived by one with PD, providing assistance to overcome FoG.

Positron Emission Tomography/Computed Tomography (PET/CT) combines metabolic and anatomical information improving the precision and accuracy of oncological diagnostics. The standardized uptake value (SUV) measures tumor metabolism, yet its accuracy is influenced by the partial volume effect (PVE), impacting small lesion detection. This study aims to refine PVE corrections for small lesions using an in-house customized, special anthropomorphic phantom. Scans of this phantom which contained spheres of different sizes were performed across four hospitals at different PET/CT systems from various manufacturers (Siemens and Philips analog PET/CT systems, GE analog and digital PET/CT systems). The phantom contained six custom-designed cylinders with embedded spheres simulating sub-centimeter (0.3, 0.5, 0.9) and centimeter (1.3, 1.9, 2.8) lesions. Scans were performed separately for each sphere in the thorax, abdomen, and pelvis regions at all sites. Recovery Coefficients (RCs) were calculated to correct SUV values, demonstrating that RCs vary by sphere size and anatomical region but not change significantly among scanners. RCs are approaching unity for larger spheres, ensuring accurate SUV measurements. However, small spheres (< 0.5 cm) exhibited significant measurement challenges due to PVE. The anthropomorphic phantom proved effective in obtaining realistic SUV-corrected values, offering a promising tool for enhancing the accuracy and standardization of PET imaging in oncology. This study underscores the necessity for advanced imaging technologies and standardized RC application in clinical settings to improve the quantification of PET imaging, particularly in small lesion detection.

Tracheal stenosis (TS) is a pathological condition characterized by a reduction in the trachea diameter. It is a common complication after prolonged endotracheal intubation but may also arise from autoimmune or inflammatory processes. Clinicians can select the most appropriate treatment option based on individual patient conditions. Therefore, precise localization and evaluation of the stenosis are essential to ensure safe and effective treatment. This review summarizes current research on TS diagnosis and assessment, encompassing functional, imaging, and bronchoscopy methods. The characteristics, advantages, and disadvantages of each technique are discussed in relation to their application in the diagnosis and assessment of TS. Bronchoscopy is considered the cornerstone of TS diagnosis, and novel adjunct imaging modalities have emerged to enhance its accuracy. We explore advanced endomicroscopic methods, such as endobronchial ultrasound (EBUS), photoacoustic endoscopy (PAE), optical coherence tomography (OCT), and confocal laser endomicroscopy (CLE). Among these, EBUS is clinically approved for diagnosing lesions with high resolution and acceptable penetration depth. OCT and CLE offer real-time imaging for peripheral lesions and potentially malignant nodules, but their use is limited by cost and availability in low-resource settings. Therefore, bronchoscopy, with biopsy techniques as needed, remains the optimal approach for diagnosing tracheal stenosis.

Background: Automated insertion of the cochlear implant electrode array can reduce the risk of intracochlear trauma. To address this, our group previously developed a hydraulic electrode insertion device, the Cochlea Hydrodrive (CHD), which automates the process using a syringe piston driven by an infusion pump. This study aims to characterize the hydraulic actuation process of the CHD and to preclinically evaluate its design.

Methods: A camera-based motion tracking test setup was developed to obtain hydraulic motion profiles. Various syringes were evaluated for their actuation properties and the optimal syringe was selected. The CHD design was adapted based on the selected syringe, incorporating a slotted stainless steel guide tube to surround the electrode during insertion. This enhanced design was tested in ex vivo insertion trials into human head specimens.

Results: The final design of the CHD demonstrated smooth and steady motion profiles at all tested velocities (0.4 mm/s, 0.1 mm/s, 0.03 mm/s). Ex vivo insertion trials confirmed these findings, with the guide tube facilitating easy alignment of the CHD in front of the round window and preventing electrode buckling.

Conclusion: Our study validates that the CHD provides reliably smooth actuation properties despite its low complexity. The use of a guide tube appears promising and could further enhance the standardization of automated electrode insertion.

Background: Facial expression muscles serve a fundamental role in the orofacial system, significantly influencing the overall health and well-being of an individual. They are essential for performing basic functions such as speech, chewing, and swallowing. The purpose of this study was to determine whether surface electromyography could be used to evaluate the health, function, or dysfunction of three facial muscles by measuring their electrical activity in healthy people. Additionally, to ascertain whether pattern recognition and artificial intelligence may be used for tasks that differ from one another.

Results: The study included 24 participants and examined three muscles (m. Orbicularis Oris, m. Zygomaticus Major, and m. Mentalis) during five different facial expressions. Prior to thorough statistical analysis, features were extracted from the acquired electromyographs. Finally, classification was done with the use of logistic regression, random forest classifier and linear discriminant analysis. A statistically significant difference in muscle activity amplitudes was demonstrated between muscles, enabling the tracking of individual muscle activity for diagnostic and therapeutic purposes. Additionally other time domain and frequency domain features were analyzed, showing statistical significance in differentiation between muscles as well. Examples of pattern recognition showed promising avenues for further research and development.

Conclusion: Surface electromyography is a useful method for assessing the function of facial expression muscles, significantly contributing to the diagnosis and treatment of oral motor function disorders. Results of this study show potential for further research and development in this field of research.