Alzheimer’s disease (AD) is a chronic central neurodegenerative disease. The pathological features of AD are the extracellular deposition of senile plaques formed by amyloid-β oligomers (AβOs) and the intracellular accumulation of neurofibrillary tangles formed by hyperphosphorylated tau protein. In this paper, an in vitro pathological model of AD based on neuronal network chip and its real-time dynamic analysis were presented. The hippocampal neuronal network was cultured on the microelectrode array (MEA) chip and induced by AβOs as an AD model in vitro to simultaneously record two firing patterns from the interneurons and pyramidal neurons. The spatial firing patterns mapping and cross-correlation between channels were performed to validate the degeneration of neuronal network connectivity. This biosensor enabled the detection of the AβOs toxicity responses, and the identification of connectivity and interactions between neuronal networks, which can be a novel technique in the research of AD pathological model in vitro.
Objective To review the progress and application of peripheral nervous microelectrode. Methods The recent articles on peripheral nervous microelectrode were extensively reviewed. The classification, the progress of the peripheral nervous microelectrode and its utilizable prospect in the control of electronic prosthesis were summarized. Results The microelectrodes had favorable functions of selective stimulation and recording. It provided an information transmitting interface between the electric prosthesis and peripheral nerves. Conclusion Peripheral nervous signal is a feasible signal source to control electronic prosthesis.
Transcranial direct current stimulation (tDCS) is a brain stimulation intervention technique, which has the problem of different criteria for the selection of stimulation parameters. In this study, a four-layer real head model was constructed. Based on this model, the changes of the electric field distribution in the brain with the current intensity, electrode shape, electrode area and electrode spacing were analyzed by using finite element simulation technology, and then the optimal scheme of electrical stimulation parameters was discussed. The results showed that the effective stimulation region decreased and the focusing ability increased with the increase of current intensity. The normal current density of the quadrilateral electrode was obviously larger than that of the circular electrode, which indicated that the quadrilateral electrode was more conducive to current stimulation of neurons. Moreover, the effective stimulation region of the quadrilateral electrode was more concentrated and the focusing ability was stronger. The focusing ability decreased with the increase of electrode area. Specifically, the focusing tended to increase first and then decrease with the increase of electrode spacing and the optimal electrode spacing was 64.0–67.2 mm. These results could provide some basis for the selection of electrical stimulation parameters.
A digital system for bioimpedance and electrical impedance tomography (EIT) measurement controlled by an ATmega16 microcontroller was constructed in our laboratory. There are eight digital electrodes using AD5933 to measure the impedance of the targets, and the data is transmitted to the computer wirelessly through nRF24L01. The structure of the system, circuit design, system testing, vitro measurements of animals' tissues and electrical impedance tomography are introduced specifically in this paper. The experimental results showed that the system relative error was 0.42%, and the signal noise ratio was 76.3 dB. The system not only can be used to measure the impedance by any two electrodes within the frequency of 1-100 kHz in a sweep scanning, but also can reconstruct the images of EIT. The animal experiments showed that the data was valid and plots were fitting with Cole-Cole theory. The testing verified the feasibility and effectiveness of the system. The images reconstructed of a salt-water tank are satisfactory and match with the actual distribution of the tank. The system improves the effectiveness of the front-end measuring signal and the stability of the system greatly.
ObjectivesThis study aimed to study the economic effect of five kinds of detection systems for nucleic acid, which were based on five kinds of working electrodes: gold electrode, glassy carbon electrode, carbon paste electrode, screen printing electrode, and indium-tin-oxide (ITO) glass electrode.MethodsThe cost of completing a single test was taken as the cost of economic analysis. The Youden index was used to represent the effect of cost-effectiveness analysis (CEA). Meanwhile, the cost-utility analysis (CUA) and incremental cost-effectiveness ratio (ICER) were used for the economic analysis of the corresponding system.ResultsThe cost of five detection systems based on gold electrode, glass carbon electrode, carbon paste electrode, screen printing electrode, and ITO glass electrode was 3.70 yuan/unit, 4.20 yuan/unit, 5.25 yuan/unit, 33.98 yuan/unit and 5.01 yuan/unit, respectively. The Youden indexes of all five systems were 1. The cost effectiveness (C/E) were 3.70, 4.20, 5.25, 33.98, and 5.01, respectively. The cost utility (C/U) were 6.61, 6.89, 9.91, 62.93, and 9.45, respectively. The C'/E and C'/U of the gold electrode detection system were the minimum (2.96 and 5.29). Compared with the system applying the gold electrode, the system using the glassy carbon electrode had ΔC >0 and ?E0 >0; When carbon paste electrode, screen printing electrode, and ITO glass electrode system were used, ?C was >0 and ?E0 was <0.ConclusionsFrom the perspective of CEA and CUA, the system using the gold electrode has the best economic effect. The sensitivity analysis proved the reliability of CEA and CUA results. According to the ICER, gold electrode or glassy carbon electrode can be used in clinical practice with the choice depending on the user.
ObjectiveThe purpose of this study was to compare the value of SEEG and subdural cortical electrodes monitoring in preoperative evaluation of epileptogenic zone. MethodsFeatures of patients using SEEG (48 cases) and subdural cortical electrodes monitoring (52 cases) to evaluate the epileptogenic zone were collected from June 2011 to June 2015. And the evaluation results, surgical effects and complications were compared. ResultsThere was no significant difference between SEEG and subdural cortical electrodes monitoring in identifying the epileptogenic zone or taking epileptic surgery, but SEEG could monitor multifocal and bilateral epileptogenic zone. And there was no significant difference in postoperative seizure control and intelligence improvement (P > 0.05). The total complication rate of SEEG was lower than subdural cortical electrodes monitoring, especially in hemorrhage and infection (P < 0.05). ConclusionsThere was no difference among SEEG and subdural cortical electrodes monitoring in surgical results, but SEEG with less hemorrhagic and infectious risks. SEEG is a safe and effective intracranial monitoring method, which can be widely used.
In order to reduce the mortality rate of cardiovascular disease patients effectively, improve the electrocardiogram (ECG) accuracy of signal acquisition, and reduce the influence of motion artifacts caused by the electrodes in inappropriate location in the clothing for ECG measurement, we in this article present a research on the optimum place of ECG electrodes in male clothing using three-lead monitoring methods. In the 3-lead ECG monitoring clothing for men we selected test points. Comparing the ECG and power spectrum analysis of the acquired ECG signal quality of each group of points, we determined the best location of ECG electrodes in the male monitoring clothing. The electrode motion artifacts caused by improper location had been significantly improved when electrodes were put in the best position of the clothing for men. The position of electrodes is crucial for ECG monitoring clothing. The stability of the acquired ECG signal could be improved significantly when electrodes are put at optimal locations.
In order to accurately localize the image coordinates and serial numbers of intraoperative subdural matrix electrodes, a matrix electrode localization algorithm for image processing is proposed in this paper. Firstly, by using point-by-point extended electrode location algorithm, the electrode is expanded point-by-point vertically and horizontally, and the initial coordinates and serial numbers of each electrode are determined. Secondly, the single electrode coordinate region extraction algorithm is used to determine the best coordinates of each electrode, so that the image coordinates and serial numbers of all electrodes are determined point-by-point. The results show that the positioning accuracy of electrode serial number is 100%, and the electrode coordinate positioning error is less than 2 mm. The algorithms in this paper can accurately localize the image coordinates and the serial numbers of a matrix electrode arranged in an arc, which could aid drawing of cortical function mapping, and achieve precise positioning of brain functional areas, so that it can be widely used in neuroscience research and clinical application based on electrocorticogram analysis.
ObjectiveTo evaluate the application of stereotactic electrode implantation on precise epileptogenic zone localization. MethodRetrospectively studied 140 patients with drug-resist epilepsy from March 2012 to June 2015, who undergone a procedure of intracranial stereotactic electrode for localized epileptogenic zone. ResultsIn 140 patients who underwent the ROSA navigated implantation of intracranial electrode, 109 are unilateral implantation, 31 are bilateral; 3 patients experienced an intracranial hematoma caused by the implantation. Preserved time of electrodes, on average, 8.4days (range 2~35 days); Obseved clinical seizures, on average, 10.8 times per pt (range 0~98 times); There were no cerebrospinal fluid leak, intracranial hematoma, electrodes fracture or patient death, except 2 pt's scalp infection (1.43%, scalp infection rate); 131 pts' seizure onset area was precisely localized; 71 pts underwent SEEG-guide resections and were followed up for more than 6 months. In the group of 71 resection pts, 56 pts were reached Engel I class, 2 were Engel Ⅱ, 3 was Engel Ⅲ and 10 were Engel IV class. ConclusionTo intractable epilepsy, when non-invasive assessments can't find the epileptogenic foci, intracranial electrode implantation combined with long-term VEEG is an effective method to localize the epileptogenic foci, especially the ROSA navigated stereotactic electrode implantation, which is a micro-invasive, short-time, less-complication, safe-guaranteed, and precise technique.
In order to solve the problems of insufficient stimulation channels and lack of stimulation effect feedback in the current electrical stimulation system, a functional array electrode electrical stimulation system with surface electromyography (sEMG) feedback was designed in this paper. Firstly, the effectiveness of the system was verified through in vitro and human experiments. Then it was confirmed that there were differences in the number of amperage needed to achieve the same stimulation stage among individuals, and the number of amperage required by men was generally less than that of women. Finally, it was verified that the current required for square wave stimulation was smaller than that for differential wave stimulation if the same stimulation stage was reached. This system combined the array electrode and sEMG feedback to improve the accuracy of electrical stimulation and performed the whole process recording of feedback sEMG signal in the process of electrical stimulation, and the electrical stimulation parameters could change with the change of the sEMG signal. The electrical stimulation system and sEMG feedback worked together to form a closed-loop electrical stimulation working system, so as to improve the efficiency of electrical stimulation rehabilitation treatment. In conclusion, the functional array electrode electrical stimulation system with sEMG feedback developed in this paper has the advantages of simple operation, small size and low power consumption, which lays a foundation for the introduction of electrical stimulation rehabilitation treatment equipment into the family, and also provides certain reference for the development of similar products in the future.