Magnetoencephalogram-based brain-computer interface for hand-gesture decoding using deep learning.

Advancements in deep learning algorithms over the past decade have led to extensive developments in brain-computer interfaces (BCI). A promising imaging modality for BCI is magnetoencephalography (MEG), which is a non-invasive functional imaging technique. The present study developed a MEG sensor-based BCI neural network to decode Rock-Paper-scissors gestures (MEG-RPSnet). Unique preprocessing pipelines in tandem with convolutional neural network deep-learning models accurately classified gestures. On a single-trial basis, we found an average of 85.56% classification accuracy in 12 subjects. Our MEG-RPSnet model outperformed two state-of-the-art neural network architectures for electroencephalogram-based BCI as well as a traditional machine learning method, and demonstrated equivalent and/or better performance than machine learning methods that have employed invasive, electrocorticography-based BCI using the same task. In addition, MEG-RPSnet classification performance using an intra-subject approach outperformed a model that used a cross-subject approach. Remarkably, we also found that when using only central-parietal-occipital regional sensors or occipitotemporal regional sensors, the deep learning model achieved classification performances that were similar to the whole-brain sensor model. The MEG-RSPnet model also distinguished neuronal features of individual hand gestures with very good accuracy. Altogether, these results show that noninvasive MEG-based BCI applications hold promise for future BCI developments in hand-gesture decoding.

Peripheral Nerve Magnetoneurography With Optically Pumped Magnetometers.

Electrodiagnosis is routinely integrated into clinical neurophysiology practice for peripheral nerve disease diagnoses, such as neuropathy, demyelinating disorders, nerve entrapment/impingement, plexopathy, or radiculopathy. Measured with conventional surface electrodes, the propagation of peripheral nerve action potentials along a nerve is the result of ionic current flow which, according to Ampere's Law, generates a small magnetic field that is also detected as an "action current" by magnetometers, such as superconducting quantum interference device (SQUID) Magnetoencephalography (MEG) systems. Optically pumped magnetometers (OPMs) are an emerging class of quantum magnetic sensors with a demonstrated sensitivity at the 1 fT/√Hz level, capable of cortical action current detection. But OPMs were ostensibly constrained to low bandwidth therefore precluding their use in peripheral nerve electrodiagnosis. With careful OPM bandwidth characterization, we hypothesized OPMs may also detect compound action current signatures consistent with both Sensory Nerve Action Potential (SNAP) and the Hoffmann Reflex (H-Reflex). In as much, our work confirms OPMs enabled with expanded bandwidth can detect the magnetic signature of both the SNAP and H-Reflex. Taken together, OPMs now show potential as an emerging electrodiagnostic tool.

A flexible adhesive surface electrode array capable of cervical electroneurography during a sequential autonomic stress challenge.

This study introduces a flexible, adhesive-integrated electrode array that was developed to enable non-invasive monitoring of cervical nerve activity. The device uses silver-silver chloride as the electrode material of choice and combines it with an electrode array consisting of a customized biopotential data acquisition unit and integrated graphical user interface (GUI) for visualization of real-time monitoring. Preliminary testing demonstrated this electrode design can achieve a high signal to noise ratio during cervical neural recordings. To demonstrate the capability of the surface electrodes to detect changes in cervical neuronal activity, the cold-pressor test (CPT) and a timed respiratory challenge were employed as stressors to the autonomic nervous system. This sensor system recording, a new technique, was termed Cervical Electroneurography (CEN). By applying a custom spike sorting algorithm to the electrode measurements, neural activity was classified in two ways: (1) pre-to-post CPT, and (2) during a timed respiratory challenge. Unique to this work: (1) rostral to caudal channel position-specific (cephalad to caudal) firing patterns and (2) cross challenge biotype-specific change in average CEN firing, were observed with both CPT and the timed respiratory challenge. Future work is planned to develop an ambulatory CEN recording device that could provide immediate notification of autonomic nervous system activity changes that might indicate autonomic dysregulation in healthy subjects and clinical disease states.

A CNN Segmentation-Based Approach to Object Detection and Tracking in Ultrasound Scans with Application to the Vagus Nerve Detection.

Ultrasound scanning is essential in several medical diagnostic and therapeutic applications. It is used to visualize and analyze anatomical features and structures that influence treatment plans. However, it is both labor intensive, and its effectiveness is operator dependent. Real-time accurate and robust automatic detection and tracking of anatomical structures while scanning would significantly impact diagnostic and therapeutic procedures to be consistent and efficient. In this paper, we propose a deep learning framework to automatically detect and track a specific anatomical target structure in ultrasound scans. Our framework is designed to be accurate and robust across subjects and imaging devices, to operate in real-time, and to not require a large training set. It maintains a localization precision and recall higher than 90% when trained on training sets that are as small as 20% in size of the original training set. The framework backbone is a weakly trained segmentation neural network based on U-Net. We tested the framework on two different ultrasound datasets with the aim to detect and track the Vagus nerve, where it outperformed current state-of-the-art real-time object detection networks.Clinical Relevance-The proposed approach provides an accurate method to detect and localize target anatomical structures in real-time, assisting sonographers during ultrasound scanning sessions by reducing diagnostic and detection errors, and expediting the duration of scanning sessions.

Influence of abdominal core training on stability control in table tennis players / Influência do treino do core abdominal sobre o controle da estabilidade nos jogadores de tênis de mesa / Influencia del entrenamiento del core abdominal en el control de la estabilidad en jugadores de tenis de mesa

ABSTRACT Introduction In recent years, there have been a number of reforms in table tennis, trends in technology development, and demands on the part of athletes to improve their competitive ability and prevent injuries. Objective Evaluate the effect of abdominal core strength training on ball control stability in table tennis players. Methods By random sampling and grouping method, the national top-level table tennis players were divided into an experimental group and a control group (17 boys in each group and seven girls in each group); the experiment lasted for one week, during which the athletes in the experimental group performed abdominal core strength training, while the athletes in the control group performed regular training. Results There was no significant difference in the longitudinal comparison of the control group before and after the experiment (P>0.05), and there was a very significant difference in the horizontal comparison between the two groups after the experiment (P<0.01). Conclusion Abdominal core strength training has a positive effect on improving the technical stability of table tennis players. Core strength can improve the athlete's attack speed and recovery. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

RESUMO Introdução Nos últimos anos, houveram uma série de reformas no tênis de mesa, tendências no desenvolvimento da tecnologia e exigências por parte dos atletas para melhorar sua capacidade competitiva bem como prevenir lesões. Objetivo Avaliar o efeito do treinamento de força do core abdominal na estabilidade do controle da bola em jogadores de tênis de mesa. Métodos Pelo método de amostragem e agrupamento aleatório, os jogadores de tênis de mesa de primeiro nível nacional foram divididos em grupo experimental e grupo controle (17 meninos em cada grupo e 7 meninas em cada grupo), o experimento durou uma semana, durante a qual os atletas do grupo experimental realizaram o treinamento de força do core abdominal, enquanto os atletas do grupo controle realizaram o treinamento normal. Resultados Não houve diferença significativa na comparação longitudinal do grupo controle antes e depois do experimento (P>0,05), e houve uma diferença muito significativa na comparação horizontal entre os dois grupos após o experimento (P<0,01). Conclusão O treinamento de força do core abdominal tem um efeito positivo na melhoria da estabilidade técnica dos jogadores de tênis de mesa. A força do core pode melhorar a velocidade de ataque do atleta e da sua recuperação. Nível de evidência II; Estudos terapêuticos - investigação dos resultados do tratamento.

RESUMEN Introducción En los últimos años, se han producido una serie de reformas en el tenis de mesa, tendencias en el desarrollo de la tecnología y demandas de los atletas para mejorar su capacidad competitiva, así como para prevenir lesiones. Objetivo Evaluar el efecto del entrenamiento de la fuerza del core abdominal en la estabilidad del control de la pelota en jugadores de tenis de mesa. Métodos Mediante el método de muestreo aleatorio y agrupación, los jugadores de tenis de mesa de alto nivel nacional se dividieron en grupo experimental y grupo de control (17 chicos en cada grupo y 7 chicas en cada grupo), el experimento duró una semana, durante la cual los atletas del grupo experimental realizaron un entrenamiento de fuerza del core abdominal, mientras que los atletas del grupo de control realizaron un entrenamiento normal. Resultados No hubo diferencias significativas en la comparación longitudinal del grupo de control antes y después del experimento (P>0,05), y hubo una diferencia muy significativa en la comparación horizontal entre los dos grupos después del experimento (P<0,01). Conclusión El entrenamiento de la fuerza del core tiene un efecto positivo en la mejora de la estabilidad técnica de los jugadores de tenis de mesa. La fuerza del core abdominal puede mejorar la velocidad de ataque y la recuperación del atleta. Nivel de evidencia II; Estudios terapéuticos - investigación de los resultados del tratamiento.