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There is much evidence pointing out eye movement alterations in several neurological diseases. To the best of our knowledge, this is the first video-oculography study describing potential alterations of eye movements in the post-COVID-19 condition. Visually guided saccades, memory-guided saccades, and antisaccades in horizontal axis were measured. In all visual tests, the stimulus was deployed with a gap condition. The duration of the test was between 5 and 7 min per participant. A group of n=9 patients with the post-COVID-19 condition was included in this study. Values were compared with a group (n=9) of healthy volunteers whom the SARS-CoV-2 virus had not infected. Features such as centripetal and centrifugal latencies, success rates in memory saccades, antisaccades, and blinks were computed. We found that patients with the post-COVID-19 condition had eye movement alterations mainly in centripetal latency in visually guided saccades, the success rate in memory-guided saccade test, latency in antisaccades, and its standard deviation, which suggests the involvement of frontoparietal networks. Further work is required to understand these eye movements’ alterations and their functional consequences.

Objective: In the study, a novel wearable miniaturized human computer interface system was designed and implemented. It allowed disabled people, who are not able to move their limbs voluntarily and speech overtly, to express their intentions and feelings just by moving their eyes. Materials & Methods: The developed system that is installed on a pair of glasses, records the electrooculogram signal and transfers the digitized data wirelessly to a laptop. Realtime analysis of the signals allows users to utilize two high performance graphical user interfaces a keypad and a game, just by their eye movements. The performance of the developed system was tested on six normal people, who typed a total number of 1071 characters successfully, to evaluate accuracy and rate of typing. It was also tested by four people with quadriplegia and cerebral palsy who performed a computer game by using their eye movements. Results: According to results of the experiments on normal people, the accuracy of recognizing the user's intention was obtained 94.1% and the average rate of communication was 7.72 characters per minute. Evaluating the usability of the system for disabled people showed that they were able to perform the computer game using their eyes. The percentage of success was evaluated as an average of 58.7%. Conclusion: The proposed system recorded and processed elecrooculogram signals with appropriate quality. The final prototype of the system was 2.6 cm× 4.5 cm in size and weighted only 15 grams. The total power consumption was measured as 123 mW. The designed keypad provided selection of each character by minimum eye movements. The system assures high performance for communication as well as high level of mobility and comfort for everyday use.

Abstract: Introduction: The saccadic paradigm has been used to investigate specific cortical networks involving attention. The behavioral and electrophysiological investigations of the SEM contribute significantly to the understanding of attentive patterns presented of neurological and psychiatric disorders and sports performance. Objective: The current study aimed to investigate absolute alpha power changes in sensorimotor brain regions and the frontal eye fields during the execution of a saccadic task. Methods: Twelve healthy volunteers (mean age: 26.25; SD: ±4.13) performed a saccadic task while the electroencephalographic signal was simultaneously recorded for the cerebral cortex electrodes. The participants were instructed to follow the LEDs with their eyes, being submitted to two different task conditions: a fixed pattern versus a random pattern. Results: We found a moment main effect for the C3, C4, F3 and F4 electrodes and a condition main effect for the F3 electrode. We also found interaction between factor conditions and frontal electrodes. Conclusions: We conclude that absolute alpha power in the left frontal cortex discriminates the execution of the two stimulus presentation patterns during SEM. [Copyright &y& Elsevier]

There is much evidence pointing out eye movement alterations in several neurological diseases. To the best of our knowledge, this is the first video-oculography study describing potential alterations of eye movements in the post-COVID-19 condition. Visually guided saccades, memory-guided saccades, and antisaccades in horizontal axis were measured. In all visual tests, the stimulus was deployed with a gap condition. The duration of the test was between 5 and 7 min per participant. A group of n = 9 patients with the post-COVID-19 condition was included in this study. Values were compared with a group ( n = 9 ) of healthy volunteers whom the SARS-CoV-2 virus had not infected. Features such as centripetal and centrifugal latencies, success rates in memory saccades, antisaccades, and blinks were computed. We found that patients with the post-COVID-19 condition had eye movement alterations mainly in centripetal latency in visually guided saccades, the success rate in memory-guided saccade test, latency in antisaccades, and its standard deviation, which suggests the involvement of frontoparietal networks. Further work is required to understand these eye movements' alterations and their functional consequences. [ABSTRACT FROM AUTHOR]

Abstract: We study a class of optimal stochastic control problems arising from the control of movements. Exact solutions are first presented for linear cases for both the during- and post-movement control problem, depending on a parameter . It is found that for the Langevin type equation and for the post-movement control case, a non-degenerate solution exists only when . For the Langevin type equation and for the during-movement control, a non-degenerate solution is found when . For the post-movement control and the Hamiltonian type equation, an optimal control signal is obtained and is non-degenerate when . Again for the during-movement control, we find an optimal non-degenerate control signal when . All results are then generalized to nonlinear control cases (the first order perturbation of linear cases). Numerical examples are included to illustrate the applications of our results. [Copyright &y& Elsevier]

Partial vitreous liquefaction (PVL) is a common physical and biochemical degenerative change in the vitreous body in which the liquid component becomes separated from collagen fiber network and this might form the pocket of liquefaction known as lacuna. The main objective of this research is to investigate how the saccade movements influence flow dynamics of the PVL. A three-dimensional model of the vitreous cavity is subjected to saccadic movement and the numerical simulations for various saccade amplitudes and volume fractions are performed. We consider concentric and eccentric configurations of the PVL with the initial spherical shape inside a spherical cavity. In this paper, a specific 3D numerical solver is developed to capture the interface effects and dynamic characteristics of a two-phase viscoelastic-Newtonian fluid flow by using the OpenFOAM CFD. The code is based on a set of time-dependent non-linear partial differential equations (PDE) such as continuity, momentum and constitutive relation for polymeric stresses tensor. The finite volume method with a modified volume-of-fluid model and dynamic mesh technique are used to solve PDEs. Firstly, the validity of the present numerical model was verified by comparing the obtained results with the analytical solutions which demonstrated remarkable agreement. Then, the time- and space-dependent velocity field, shear stress and normal stress distributions were computed and how the PVL responds to the saccadic motions was discussed., (Copyright © 2020 Elsevier Ltd. All rights reserved.)