Featured Articles

Transcranial Focused Ultrasound Stimulation of Periaqueductal Gray for Analgesia 789 444 IEEE Transactions on Biomedical Engineering (TBME)

Transcranial Focused Ultrasound Stimulation of Periaqueductal Gray for Analgesia

The transcranial focused ultrasound (tFUS) stimulation can achieve the effect of analgesia, and provides new insights into the development of non-invasive analgesic technology in the future.

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Global Sensitivity Analysis of Four Chamber Heart Hemodynamics Using Surrogate Models 789 444 IEEE Transactions on Biomedical Engineering (TBME)

Global Sensitivity Analysis of Four Chamber Heart Hemodynamics Using Surrogate Models

This is the first study demonstrating the feasibility of Gaussian Process Emulators as surrogate models for performing global sensitivity analysis of human blood flow in the heart.

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Artificial Intelligence Enables Real-Time and Intuitive Control of Prostheses via Nerve Interface 789 444 IEEE Transactions on Biomedical Engineering (TBME)

Artificial Intelligence Enables Real-Time and Intuitive Control of Prostheses via Nerve Interface

This article demonstrates and evaluates the performance of an artificial intelligence motor decoder using neural signals recorded from the residual peripheral nerves of amputees to control neuroprostheses in real-time for long-term uses.

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Removal of Transcranial Alternating Current Stimulation EEG Artifacts Using Blind Source Separation and Wavelets 789 444 IEEE Transactions on Biomedical Engineering (TBME)

Removal of Transcranial Alternating Current Stimulation EEG Artifacts Using Blind Source Separation and Wavelets

This study proposes a novel, combined method to clean EEG data collected during transcranial alternating current stimulation (tACS), making it possible to investigate the effects of tACS on EEG signals.

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An Occupational Shoulder Exoskeleton Reduces Muscle Activity and Fatigue During Overhead Work 789 444 IEEE Transactions on Biomedical Engineering (TBME)

An Occupational Shoulder Exoskeleton Reduces Muscle Activity and Fatigue During Overhead Work

The passive shoulder Exo4Work exoskeleton provides one-third of the arm’s gravitational torque, and reduces anterior deltoid activity and fatigue during overhead work. The hindrance during non-overhead tasks was minimized.

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Visualization of Human Skeletal Muscle Mechanical Anisotropy by Using Dual-Direction Shear Wave Imaging 789 444 IEEE Transactions on Biomedical Engineering (TBME)

Visualization of Human Skeletal Muscle Mechanical Anisotropy by Using Dual-Direction Shear Wave Imaging

This is the first study to visualize the mechanical anisotropy of human skeletal muscle by the new proposed dual-direction shear wave imaging mechanism.

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An EMG-Assisted Muscle-Force Driven Finite Element Analysis Pipeline to Investigate Joint- and Tissue-Level Mechanical Responses in Functional Activities: Towards a Rapid Assessment Toolbox 788 444 IEEE Transactions on Biomedical Engineering (TBME)

An EMG-Assisted Muscle-Force Driven Finite Element Analysis Pipeline to Investigate Joint- and Tissue-Level Mechanical Responses in Functional Activities: Towards a Rapid Assessment Toolbox

This study established an electromyography-assisted neuromusculoskeletal rigid-body and finite element modeling pipeline enabled for large cohorts studies, encouraging further research to investigate the pipeline’s potential for personalized treatment-planning of knee osteoarthritis.

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A Handheld Steerable Surgical Drill With a Novel Miniaturized Articulated Joint Module for Dexterous Confined-Space Bone Work 789 444 IEEE Transactions on Biomedical Engineering (TBME)

A Handheld Steerable Surgical Drill With a Novel Miniaturized Articulated Joint Module for Dexterous Confined-Space Bone Work

This article presents a handheld steerable drill with a 4.5-mm miniaturized tip capable of bending 65 degrees to minimize collateral tissue damage to patients for a better clinical outcome.

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O-pH: Optical pH Monitor to Measure Dental Biofilm Acidity and Assist in Enamel Health Monitoring 2008 1220 IEEE Transactions on Biomedical Engineering (TBME)

O-pH: Optical pH Monitor to Measure Dental Biofilm Acidity and Assist in Enamel Health Monitoring

O-pH measures dental biofilm’s acidity by capturing fluorescence of Sodium Fluorescein, an FDA approved chemical dye, and provides quantitative feedback to assist in oral health monitoring.

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HAILO: A Sensorised Hand Splint for the Exploration of Interface Forces 776 444 IEEE Transactions on Biomedical Engineering (TBME)

HAILO: A Sensorised Hand Splint for the Exploration of Interface Forces

This study presents a wearable device for the monitoring of pressure and shear interaction between the hand and a thumb splint, enabling the assessment of disease characteristics in hand arthritis.

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Knock-in of a Large Reporter Gene via the High-Throughput Microinjection of the CRISPR/Cas9 System 780 435 IEEE Transactions on Biomedical Engineering (TBME)

Knock-in of a Large Reporter Gene via the High-Throughput Microinjection of the CRISPR/Cas9 System

This work demonstrates the microinjection of CRISPR/Cas9 with an enhanced green fluorescent protein (GFP) donor template into single HepG2 cells can achieve reporter gene knock-in targeting the adeno-associated virus site 1 locus. Homology-directed repair-mediated knock-in can be observed with an efficiency of 41%. Assessment via T7E1 assay indicates that the GFP knock-in cells exhibit no detectable changes at potential off-target sites. A case study of injecting the GFP knock-in cells into zebrafish (Danio rerio) embryos to form an in vivo tumor model is conducted. Results demonstrate the efficiency of combining microinjection with the CRISPR/Cas9 system in achieving gene knock-in.

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MRI-Guided Cardiac RF Ablation for Comparing MRI Characteristics of Acute Lesions and Associated Electrophysiologic Voltage Reductions 2560 1427 IEEE Transactions on Biomedical Engineering (TBME)

MRI-Guided Cardiac RF Ablation for Comparing MRI Characteristics of Acute Lesions and Associated Electrophysiologic Voltage Reductions

This study characterizes permanent and transient injury caused by cardiac RF ablation in a preclinical model. Native-contrast MRI features of ablation were investigated in relation to catheter-based electrophysiologic (EP) signals inherently co-registered within the same coordinate frame, and histologically validated. Specifically, we show that bipolar voltage was reduced in the presence of both the permanent T1-derived RF lesion and transient T2-derived edema. These results suggest that these regions are distinct in native-contrast MRI, but not differentiable using bipolar voltage. Intraprocedural MRI visualization distinguishing transient and permanent injury could guide creation of more complete durable RF ablations, reducing arrhythmia recurrence.

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Quantification and 3D Localization of Magnetically Navigated Superparamagnetic Particles Using MRI in Phantom and Swine Chemoembolization Models 780 435 IEEE Transactions on Biomedical Engineering (TBME)

Quantification and 3D Localization of Magnetically Navigated Superparamagnetic Particles Using MRI in Phantom and Swine Chemoembolization Models

Author(s): Ning Li, Cyril Tous, Ivan P. Dimov, Dominic Cadoret, Phillip Fei, Yasamin Majedi, Simon Lessard, Zeynab Nosrati, Katayoun Saatchi, Urs O. Häfeli, An Tang, Samuel Kadoury, Sylvain Martel, Gilles…

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Estimating the neovascularity of human finger tendon through high-frequency ultrasound micro-Doppler imaging 780 435 IEEE Transactions on Biomedical Engineering (TBME)

Estimating the neovascularity of human finger tendon through high-frequency ultrasound micro-Doppler imaging

High-frequency micro-Doppler imaging (HFμDI) based on 40-MHz ultrafast ultrasound imaging was proposed for visualizing the neovascularization in injured finger tendons through block-wise singular value decomposition filtering and curvilinear structure enhancement. Small animal imaging experiments revealed that HFμDI provides excellent performance and the minimum vessel size was 35 μm without contrast agents. Neovascularization was clearly observed in injured finger tendons during the early phase of healing (weeks 11–21) and regressed from week 52-56. Neovascular density decreased by approximately 1.8%–8.0% after 4 weeks of rehabilitation. The experimental results indicate the potential of HFμDI for injured finger tendon evaluations.

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Improving the Energy Cost of Incline Walking and Stair Ascent with Ankle Exoskeleton Assistance in Cerebral Palsy 150 150 IEEE Transactions on Biomedical Engineering (TBME)

Improving the Energy Cost of Incline Walking and Stair Ascent with Ankle Exoskeleton Assistance in Cerebral Palsy

Author(s): Ying Fang, Greg Orekhov, Zachary F. Lerner

Graded walking terrains pose significant mobility challenges for individuals with movement disorders, including those with cerebral palsy (CP). We tested the ability of a novel battery-powered ankle exoskeleton to improve stair, incline, and real-world mixed-terrain walking in seven individuals with CP. Adaptive ankle assistance improved the energy cost of steady-state incline walking by 14% and stair ascent by 21% compared to walking without the device. This is the first study to demonstrate safety and performance benefits of ankle exoskeleton assistance on graded terrains in CP, and it encourages future studies to evaluate assistance on mixed-terrain walking in free-living environments.

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3D Acoustic Manipulation of Living Cells and Organisms Based on 2D Array IEEE Transactions on Biomedical Engineering (TBME)

3D Acoustic Manipulation of Living Cells and Organisms Based on 2D Array

This work aims to realize programmable manipulation for living cells and micro-organisms in a common Petri dish by using holographic acoustic tweezers. Based on a self-developed 2D ultrasound matrix array, we successfully synthesize various complex acoustic fields and achieve the precise regulation of the fields both in space and time, and further build a holographic acoustic tweezer system compatible with microscopic imaging. This system innovatively realizes multidimensional translation, rotation, orientation, and levitation of living cells and micro-organisms, thereby demonstrating their value for advancing research in the fields of cell assembly, tissue engineering, and micro-robot driving.

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Electroporation Microchip With Integrated Conducting Polymer Electrode Array for Highly Sensitive Impedance Measurement IEEE Transactions on Biomedical Engineering (TBME)

Electroporation Microchip With Integrated Conducting Polymer Electrode Array for Highly Sensitive Impedance Measurement

An in vitro platform is presented that monitors the degree of electroporation while cells are treated with pulsed electric fields. The developed electroporation chip can assess the integrity of a monolayer of cells by performing electrochemical impedance spectroscopy with microelectrodes. The sensitivity of the system is significantly enhanced by reducing the impedance of the sensing electrodes which is achieved by applying a PEDOT:PSS coating. The integrated system of sensing and stimulation electrodes provides feedback on treatment progression and can be used to study electroporation dynamics.

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3D Transcranial Ultrasound Localization Microscopy in the Rat Brain with a Multiplexed Matrix Probe IEEE Transactions on Biomedical Engineering (TBME)

3D Transcranial Ultrasound Localization Microscopy in the Rat Brain with a Multiplexed Matrix Probe

Ultrasound Localization Microscopy (ULM) provides high-resolution imaging of the microcirculation in-depth in living tissue. Micrometric bubbles are injected into the bloodstream and localized individually to reconstruct the vascularization of an organ. This work presents an implementation of volumetric ULM with a multiplexed matrix probe driven by a single commercial ultrasound scanner. Multiple optimizations enabled acquiring up to 100,000 volumes at 250 Hz during 7 minutes for ULM imaging of the rat brain. After reconstruction, vessels are revealed down to 31 µm in diameter under the intact skull of the animal, with blood flows from 4.3 to 28.4 mm/s.

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A handheld fiber-optic probe to enable optical coherence tomography of oral soft tissue IEEE Transactions on Biomedical Engineering (TBME)

A handheld fiber-optic probe to enable optical coherence tomography of oral soft tissue

This work presents a small, light-weight scanning probe for optical coherence tomography. We present an all-fiber optical design and integrate this with a magnetic scanning mechanism to create a probe the size of a pen (10mm x 140mm) and weighing only 10 grams. To demonstrate the high image quality, we performed imaging on the soft tissue in the mouths of six patients under-going examination for oral lichen planus. Our images show clear distinctions between normal and diseased tissue.

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Performance Evaluation of Magnetic Resonance Coupling Method for Intra-Body Network (IBNet) IEEE Transactions on Biomedical Engineering (TBME)

Performance Evaluation of Magnetic Resonance Coupling Method for Intra-Body Network (IBNet)

Author(s): Sayemul Islam, Albert Kim

The study presents magnetic resonance (MR) coupling as a promising method for the intra-body network (IBNet) by demonstrating effective signal transmission in the human body. A comparative performance evaluation revealed that the MR coupling exhibited a path loss (PL) of under 33 dB (at 13.56 MHz), which is lower than other methods (galvanic, capacitive, or RF). The angular orientation between the transmitter and receiver showed a minor variation (∆PL ≤ 0.62 dB) but moderate dependency on distance (0.05 dB/cm). Different postures did not affect the communication (∆PL ≤ 0.21 dB). Multi-nodal transmission using MR coupling also showed successful communication.

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A Novel Capsule-Delivered Enteric Drug-Injection Device for Delivery of Systemic Biologics: A Pilot Study in a Porcine Model IEEE Transactions on Biomedical Engineering (TBME)

A Novel Capsule-Delivered Enteric Drug-Injection Device for Delivery of Systemic Biologics: A Pilot Study in a Porcine Model

Author(s): Sunandita Sarker, Ben Wankum, Jeff Shimizu, Ryan Jones, Benjamin Terry

Here, we report a swallowable capsule for intestinal drug delivery (SCIDD) with the potential of directly injecting biological therapeutics into the small intestine wall. The design, optimization, and validation of the SCIDD’s primary subsystems were performed both ex-vivo and in-vivo. The assembled capsule was further tested in vivo to validate the actuation sequence which showed a 70% success rate in an animal model. A drug delivery study indicated systemic uptake of adalimumab via SCIDD compared with luminal delivery in the small intestine. The pilot study presented here establishes that the novel platform could be used to orally deliver systemic biologics.

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Simultaneous localized brain mild hyperthermia and blood-brain barrier opening via feedback-controlled transcranial MR-guided focused ultrasound and microbubbles IEEE Transactions on Biomedical Engineering (TBME)

Simultaneous localized brain mild hyperthermia and blood-brain barrier opening via feedback-controlled transcranial MR-guided focused ultrasound and microbubbles

We present a synergistic focused ultrasound-based brain drug delivery method for both spatiotemporally precise transcranial mild hyperthermia and simultaneous localized blood-brain barrier (BBB) opening. We demonstrated that with the presence of microbubbles, transcranial MR-guided focused ultrasound mild hyperthermia can be achieved at significantly reduced powers and prolonged BBB opening can be simultaneously achieved with hyperthermia sonications in a rodent model. No structural abnormality, edema, hemorrhage, or acute microglial activation was observed in the target region via MR imaging and histology. This study provides a new strategy for enhanced drug delivery in brain tissues with a high clinical translation potential.

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Jet-Induced Tissue Disruption for Blood Release IEEE Transactions on Biomedical Engineering (TBME)

Jet-Induced Tissue Disruption for Blood Release

Jet injectors use a high-speed fluid jet to pierce the skin, and can be used not only to deliver drugs, but also to release capillary blood, much like a lancet. This work provides new histological information about tissue disruption induced by a circular jet, a lancet-inspired slot-shaped jet, and a lancet prick. The slot-shaped jet caused shallower penetration with smaller wound volume but disrupted more vascular endothelium than the circular jet. The findings suggest that jet injection can be designed to release capillary blood in volumes similar to that of a lancet prick, and thus be useful in blood testing.

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Inverse Reinforcement Learning Intra-operative Path Planning for Steerable Needle IEEE Transactions on Biomedical Engineering (TBME)

Inverse Reinforcement Learning Intra-operative Path Planning for Steerable Needle

Author(s): Elena De Momi

This work presents a safe and effective keyhole neurosurgery intra-operative planning framework for flexible neurosurgical robots. The framework is intended to support neurosurgeons during the intraoperative procedure to react to a dynamic environment. The proposed system integrates inverse reinforcement learning path planning algorithm, based on expert demonstrations, with a realistic, time-bounded simulator based on Position-based Dynamics simulation that mocks brain deformations due to catheter insertion and a simulated robotic system. Simulation results performed on a human brain dataset show that that the presented intra-operative steerable needle path planner is able to avoid anatomical obstacles while optimising surgical criteria.

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Impedance Properties of Multi-Optrode Biopotential Sensing Arrays IEEE Transactions on Biomedical Engineering (TBME)

Impedance Properties of Multi-Optrode Biopotential Sensing Arrays

Author(s): Nigel Hamilton Lovell

This work demonstrates the advantage of using an optically inspired, liquid-crystal based biopotential recording technology over a conventional electrode and amplifier system. This optical electrode (optrode) system is favorable for its ability to adjust the input impedance levels in dense-array configurations. We conducted a benchtop experiment and circuit simulations to investigate the relationship between liquid-crystal transducer and interface impedances and the recording-site size in order to better understand the impedance properties of optrodes. This work is the starting point to optimize the layout and configuration of multi-optrode arrays to target various biomedical applications.

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Muscle-Specific High-Density Electromyography Arrays for Hand Gesture Classification IEEE Transactions on Biomedical Engineering (TBME)

Muscle-Specific High-Density Electromyography Arrays for Hand Gesture Classification

Author(s): Leo K. Cheng

Muscle-specific, high-density, flexible electromyography (HD-EMG) electrode arrays were designed and applied to capture the myoelectric activity of key intrinsic hand muscles to classify motions and to allow individual analysis of each muscle. Myoelectric activity was displayed as spatio-temporal maps to visualize muscle activation. Time-domain and temporal-spatial HD-EMG features were extracted to train machine machine-learning classifiers to predict user motion, using data collected from intrinsic hand muscles. The muscle-specific electrode arrays can be combined with EMG decomposition techniques to assess motor unit activity and in applications involving the analysis of dexterous hand motions.

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Sleep Monitoring Using Ear-Centered Setups: Investigating the Influence From Electrode Configurations IEEE Transactions on Biomedical Engineering (TBME)

Sleep Monitoring Using Ear-Centered Setups: Investigating the Influence From Electrode Configurations

Author(s): Mike Lind Rank, Preben Kidmose

We combine ear-EEG sleep recordings with a state-of-the-art sleep scoring model, ‘seqsleepnet’, to investigate the upper limits of mobile sleep scoring. We manage to further improve on the state of the art in this field, and perform a detailed analysis of the influence of electrode positioning. From this, we find a general rule of thumb that as long a data set contain EOG information and electrode distance on the order of the width of the head, then good automatic sleep scoring is possible. We also find indications that the obtained automatic scoring may be more reliable than the manual scoring.

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Design a Novel BCI for Neurorehabilitation Using Concurrent LFP and EEG Features: A Case Study IEEE Transactions on Biomedical Engineering (TBME)

Design a Novel BCI for Neurorehabilitation Using Concurrent LFP and EEG Features: A Case Study

Author(s): Yi Sun, Yu Qi, Yueming Wang, Cuntai Guan, Yu Sun

This work introduced for the first time a novel BCI that incorporate both intracortical LFP and scalp EEG (named, LFP-EEG-BCI) for motor intention decoding during neurorehabilitation. Concurrent intracortical and scalp signals were collected from a paraplegic patient undergoing motor imagery (MI) neurorehabilitation training. A common spatial filter approach was adopted for feature extraction and a decision fusion strategy was further introduced to obtain the decoding results. Transfer learning approach was also utilized to reduce the calibration. The proposed novel LFP-EEG-BCI may lead to new directions for developing practical neurorehabilitation systems in clinical applications.

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Acoustic beam mapping for guiding HIFU therapy in vivo using sub-therapeutic sound pulse and passive beamforming IEEE Transactions on Biomedical Engineering (TBME)

Acoustic beam mapping for guiding HIFU therapy in vivo using sub-therapeutic sound pulse and passive beamforming

This work aims at deriving the therapeutic energy distribution within the tissue at the pre-treatment stage to guide the HIFU procedure. A beamforming-based energy mapping technique was established to estimate in-situ beam path of the therapeutic energy in a non-invasive way, which is extremely useful in visualizing the sound beam, especially its focal region, for the HIFU surgery. Effectiveness of this technique has been validated with simulations, in-vitro experiments, ex-vivo experiments and in-vivo tests on a rabbit. The technique is safe, easy to be applied in clinical practices, and can potentially be adapted to other ultrasound-related beam manipulating applications.

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Sensitivity Analysis Highlights the Importance of Accurate Head Models for Electrical Impedance Tomography Monitoring of Intracerebral Hemorrhagic Stroke IEEE Transactions on Biomedical Engineering (TBME)

Sensitivity Analysis Highlights the Importance of Accurate Head Models for Electrical Impedance Tomography Monitoring of Intracerebral Hemorrhagic Stroke

In this study, we investigate the role of accurate head modeling in electrical impedance tomography (EIT) monitoring of intracerebral hemorrhagic stroke. We compared anatomically detailed six-layer and simplified three-layer finite element models and computed and visualized scalp potentials, lead fields and sensitivity distributions with various perturbations. In addition, inverse imaging was examined with selected cases. Our results show that detailed anatomy and realistic tissue conductivities have significant effect on the simulated measurements, the sensitivities and the EIT images reconstructed from the simulated measurement data. We conclude it’s important to consider the anatomical details such as cerebrospinal fluid in EIT research.

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Estimating Ground Reaction Force and Center of Pressure Using Low-Cost Wearable Devices IEEE Transactions on Biomedical Engineering (TBME)

Estimating Ground Reaction Force and Center of Pressure Using Low-Cost Wearable Devices

Author(s): Brandon Oubre, Sunghoon Ivan Lee

Ambulatory monitoring of ground reaction force (GRF) and plantar center of pressure (CoP) could improve management of health conditions that impair mobility. This work presents a system consisting of 1) an insole instrumented with six force-sensitive resistors and 2) a string-based knee angle sensor. Supervised machine learning models estimated weight-normalized GRF and shoe size-normalized CoP, which were re-scaled to obtain GRF and CoP. Normalized models accurately estimated GRF and CoP despite deficiencies in force sensor data. Ambulatory use of the proposed system could enable objective, longitudinal monitoring of severity and progression for a variety of health conditions.

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Gamma Power of Electroencephalogram Arousal is Modulated by Respiratory Event Type and Severity in Obstructive Sleep Apnea IEEE Transactions on Biomedical Engineering (TBME)

Gamma Power of Electroencephalogram Arousal is Modulated by Respiratory Event Type and Severity in Obstructive Sleep Apnea

This work investigated breathing obstruction-related arousal intensity via high-frequency spectral content in nocturnal electroencephalogram (EEG). Gamma band (30–40 Hz) power in EEG was studied during arousals caused by different respiratory events in 869 patients with suspected obstructive sleep apnea (OSA).
Arousal gamma power was higher in deeper sleep and increased alongside the respiratory event severity. As elevated gamma activity could indicate a greater shift towards wakefulness, the results illustrate that the magnitude of sleep disruption might vary depending on the respiratory event characteristics. These findings can bring more insight into respiratory event-related sleep fragmentation in OSA severity assessment.

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