Medical engineering & physics
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This paper presents a new online single-trial EEG-based brain-computer interface (BCI) for controlling hand holding and sequence of hand grasping and opening in an interactive virtual reality environment. The goal of this research is to develop an interaction technique that will allow the BCI to be effective in real-world scenarios for hand grasp control. One of the major challenges in the BCI research is the subject training. ⋯ The experimental evaluation on ten naïve subjects demonstrated that an average classification accuracy of 75.4% was obtained during the first experiment session (day) after about 3 min of online training without offline training, and 81.4% during the second session (day). The average rates during third and eighth sessions are 79.0% and 84.0%, respectively, using previously calculated classifier during the first sessions, without online training and without the need to calibrate. The results obtained from more than 5000 trials on ten subjects showed that the method could provide a robust performance over different experiment sessions and different subjects.
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Polysomnographic signals are usually recorded from patients exhibiting symptoms related to sleep disorders such as obstructive sleep apnea (OSA). Analysis of polysomnographic data allows for the determination of the type and severity of sleep apnea or other sleep-related disorders by a specialist or technician. The usual procedure entails an overnight recording several hours long. ⋯ An index measure based on the distribution frequencies of the oscillatory modes yielded a sensitivity of 81.0% (for 95% specificity) for the detection of OSA. Two other index measures based on the relation between the area and the maximum of the 1st and 2nd halves of the frequency histogram both yielded a sensitivity of 76.2% (for 95% specificity). Although further tests will be needed to test the reproducibility of these results, the proposed measures seem to provide a fast method to screen OSA patients, thus reducing the costs and the waiting time for diagnosis.
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Clinical Trial
The effect of FES of the tibial nerve on physiological activation of leg muscles during gait.
The effects of surface functional electrical stimulation (FES) of the tibial nerve of healthy subjects were evaluated. The FES was applied at three different times during gait: early, mid and late stances. The purpose of this work is to understand the effect of unilateral stimulation on the bilateral activation patterns of leg muscles, because FES is used in practice to improve gait, while associated neuromuscular change is not often measured. ⋯ For the semitendinosus, this was a difference of 6-7microV, with p<0.05. For the tibialis anterior, this was a difference of 7-15microV, with a significance of p=0.00, respectively. This information is important for future applications of stimulation as it means that stimulation not only affects the stimulated muscle but also the physiological motor control by the CNS.
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The mechanical environment considerably affects the evolution of the bone healing process. However, the effect of an external cyclic stimulation on the process has not yet been fully clarified. The aim of the present work is to evaluate the distribution of different mechanical variables in the fracture callus when an external cyclic stimulation is applied at different frequencies, in order to investigate those stimuli most likely to regulate bone healing. ⋯ We conclude that the change in the frequency of the external mechanical stimulus directly affects the interstitial fluid flow velocity in the fracture callus. This change in the fluid flow velocity may induce movement of wastes, feeds or growth factors, as well as stimulating cellular differentiation and proliferation by means of changes in the mechanical environment of the callus. In addition, the results of this work suggest that, to obtain a more significant effect of cyclic stimulation, higher frequencies with lower amplitude than those normally used in previous experimental works are needed.
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We have developed a method that allows biological tissues to be adhered together with minimal invasion by delivering integrated low-level energies from heat, pressure, and vibration. Tensile tests on adhered slices of porcine aorta were performed to determine the relationships between adhesive strength and conditions such as adhesion temperature, time, pressure, and vibration. ⋯ Adhesion strength increased in proportion to temperature, time, and pressure, and also in the presence of vibration, indicating that vibrational energy contributes to the adhesive mechanism and strength. Adhesive stability, the effect of heat on adhesive strength, and the ability of tissue to adhere to artificial materials were also clarified.