Sample Dominance Aware Framework via Non-Parametric Estimation for Spontaneous Brain-Computer Interface

Deep learning has shown promise in decoding brain signals, such as electroencephalogram (EEG), in the field of brain-computer interfaces (BCIs). However, the non-stationary characteristics of EEG signals pose challenges for training neural networks to acquire appropriate knowledge. Inconsistent EEG signals resulting from these non-stationary characteristics can lead to poor performance. Therefore, it is crucial to investigate and address sample inconsistency to ensure robust performance in spontaneous BCIs. In this study, we introduce the concept of sample dominance as a measure of EEG signal inconsistency and propose a method to modulate its effect on network training. We present a two-stage dominance score estimation technique that compensates for performance degradation caused by sample inconsistencies. Our proposed method utilizes non-parametric estimation to infer sample inconsistency and assigns each sample a dominance score. This score is then aggregated with the loss function during training to modulate the impact of sample inconsistency. Furthermore, we design a curriculum learning approach that gradually increases the influence of inconsistent signals during training to improve overall performance. We evaluate our proposed method using public spontaneous BCI dataset. The experimental results confirm that our findings highlight the importance of addressing sample dominance for achieving robust performance in spontaneous BCIs.Comment: 5 pages, 2 figure

Kraft und Beweglichkeit der Schulter bei koreanischen Volleyballspielern unterschiedlicher Spielklassen und Spielpositionen

Zusammenfassung Ziel der vorliegenden Untersuchung war es, mit isokinetischen und kinematischen Methoden umfassendere und präzisere Ergebnisse für die Prävention im Volleyball aufzuzeigen. Hierfür wurden isokinetische Kraft- und kinematische Beweglichkeitsmessungen durchgeführt, um die muskulären Verhältnisse des Schultergelenkes genauer zu untersuchen. Bei der vorliegenden Studie nahmen 86 Probanden aus vier unterschiedlichen Spielklassen teil. 21 Probanden wurden aus der Profiliga rekrutiert, 24 aus der Uni-Liga, 21 aus dem Schulsport-Turnier, 20 in der Kontrollgruppe. Für die Innen- und Außenrotation des Schultergelenkes wurden konzentrische Messungen des maximalen Drehmoments durchgeführt. Sowohl die dominante, als auch die nichtdominante Schulter wurden bei Winkelgeschwindigkeiten von 60 °∕s und 180 °∕s auf das maximale Drehmoment getestet. Die Beweglichkeitmessung der Schulter wurde mit einer dreidimensionalen Bewegungsanalyse durchgeführt. Die vorliegenden Ergebnissen zeigen, dass die Profiligaspieler bei den Winkelgeschwindigkeiten von 60 °/s mit 65,9 Nm die höchsten Werte aller Spielklassen beim maximalen Drehmoment der IRO an der dominanten Seite aufwiesen. Die Profi - Spielerinnen zeigten mit 48 % das niedrigste Verhältnis von ARO / IRO. Bei den Profiligaspielern ergab die Messung der maximalen Innenrotationsbeweglichkeit an der dominanten Seite eine deutliche Einschränkung gegenüber der nichtdominante Seite. Die Profi - Spieler zeigten mit 45 % das niedrigste Verhältnis von maximaler IRO zu ARO von allen Spielklassen. Beim Vergleich der Ergebnisse von Angriffsspielern zeigten sich Unterschiede des maximalen Drehmoments (60 °/s) mit IRO und ARO (DS), der maximalen Schulterrotation (DS) und Verhältnis von maximaler Außen- zu Innenrotation an der dominanten Seite. Die Spieler mit früheren Schultergelenkverletzungen zeigten Unterschiede im maximalen Drehmoments bei ARO (60 °/s) (DS), maximalen Drehmomentverhältnis zwischen ARO und IRO (60 °/s), sowie der maximalen Schulterrotation. Die Prävention sind hier der Ausgleich der muskulären Dysbalance mit Behebung sowohl der Verkürzungen, als auch der Abschwächungen. Solche Dysbalancen lassen sich frühzeitig diagnostizieren. Die untersuchten Ligen in der vorliegenden Studie gleichen sich bezüglich des Verletzungsrisikos, wobei dies für die Schulsportspieler nur in vermindertem Umfang galt. Wie schon seit einigen Jahren gefordert wird, muss der Verletzungsprävention im Training eine größere Bedeutung beigemessen werden. Abstract The Shoulder overuse injuries are common in volleyball players, especially during spike motion. Muscle strength and range of motion of the shoulder rotation are considered to be important during spiking. It would also be worth to find out if there were differences in shoulder strength and range of motion among these volleyball players with and without shoulder injury history in order to design appropriate shoulder injury rehabilitation and prevention training programs for each player. In this study, 86 players from 4 different levels were tested, 21 from the professional league, 24 from the university league, 21 from the middle- and high school league and the rest 20 from the control group. Isokinetic concentric strength of the shoulder rotators were tested at angular velocities of 60°/s and 180°/s by using the Biodex, and passive range of motion of the shoulder rotation was assessed using with the Simi-motion. The strength test shows that the highest torque of 65.9Nm (60 °/s) on the dominant side was measured in the professional league players and it was the highest among the 4 test groups. The 48% of professional players show the lowest level of the ER/IR values and the 45% on the dominant side of professional players the lowest level of “max. IR to ER,” which is the lowest of all test player groups. According to the test results, the dominant side shows the clear limitation of elasticity of inner rotation among professional league players (compared to the non-dominant side). According to the test results in the attackers, the differences are to see in following factors like a isokinetic strength (60 °/s) of IR and ER (DS), maximal value of shoulder rotation (DS) and the ratio between the maximal ER and the IR on the dominant side. The players who were injured in the history of shoulder show the differences in the isokinetic strength of ER (60 °/s), the strength ratio between ER and IR (60 °/s) and the maximal shoulder rotation (compared to the players without injury in the past). We recommended functional exercises that improve both external rotators strength and stretching exercise for internal rotation in the dominant side during the prevention programs in volleyball players. In addition, hypermobility in the external rotation of dominant side for volleyball players should be looked over to prevent the injury

Channel Optimized Visual Imagery based Robotic Arm Control under the Online Environment

An electroencephalogram is an effective approach that provides a bidirectional pathway between the user and computer in a non-invasive way. In this study, we adopted the visual imagery data for controlling the BCI-based robotic arm. Visual imagery increases the power of the alpha frequency range of the visual cortex over time as the user performs the task. We proposed a deep learning architecture to decode the visual imagery data using only two channels and also we investigated the combination of two EEG channels that has significant classification performance. When using the proposed method, the highest classification performance using two channels in the offline experiment was 0.661. Also, the highest success rate in the online experiment using two channels (AF3-Oz) was 0.78. Our results provide the possibility of controlling the BCI-based robotic arm using visual imagery data.Comment: 4 pages, 2 figures, 3 table

A Case of Inadvertent Anterior Chamber and Corneal Stromal Injection with Antibiotics during Cataract Operation

Purpose: To report a case of inadvertent anterior chamber and cornea stromal injection with high dose antibiotics and steroids during cataract operation. Methods: During cataract operation on a 78 year-old female patient, high dose gentamicin (20 mg/0.5 ml) and dexamethasone (2 mg/0.5 ml) were inadvertently injected into the anterior chamber and cornea stroma when making cornea edema for sealing of the incision sites. Anterior chamber irrigation with balanced salt solution (BSS) was immediately administered. On postoperative day one, extensive cornea edema was noted, and best-corrected visual acuity was 0.2. Descemet's membrane folds were observed around the corneal incision sites. Topical 5% NaCl and 1% prednisolone were started. Results: Four weeks postoperatively, corneal edema began to reduce significantly. At four months postoperatively, corneal edema fully resolved, and best-corrected visual acuity was 0.8. However, some Descemet's membrane folds still remained, and a decrease in the number of endothelial cells was noted by specular microscope. Conclusions: In this case involving anterior chamber and cornea stromal injection with high dose antibiotics and steroids, immediate anterior chamber irrigation with balanced salt solution seemed an appropriate management, and the patient's long-term visual acuity appears good. To prevent such mistakes, precise labeling of all solutions and use of different syringe needles should be considered.ope