E Actitrode: The new selective stimulation interface for functional movements in hemiplegics patients

We describe the new multi-contact electrode-array for surface electrical stimulation, and the corresponding interface device that allows on-line selection of the conductive fields during the application of the system. This new device has a specific value for therapeutic applications of electrical stimulation since it allows effective generation of desired functional movements. The user-friendly interface also allows patients at home to select the optimal electrode array; thereby, to receive therapies out of the clinical environment. The electrode was tested in three post-stroke hemiplegics patients. The pilot experiments showed that system works sufficiently good for control of fingers during grasp and release functions without the interference of the wrist movement. The use of electrode is also envisioned for many other applications (foot-drop fitness, shoulder subluxation, etc)

A novel fully fast recovery EMG amplifier for the control of neural prosthesis

Ovaj članak predstavlja novo EMG (elektromiografsko) brzo oporavljivo pojačalo, koje se može koristiti kao sučelje za kontrolu neuronskih proteza. Osnova predloženog električnog kruga je standardno instrumentacijsko pojačalo implementirano pomoću tri operacijska pojačala s integratorom u negativnoj povratnoj petlji diferencijalnog pojačala. Standardno instrumentacijsko pojačalo s tri operacijska pojačala je modificirano uvođenjem analogne linije za kašnjenje između prvog stupnja (diferencijalni ulaz - diferencijalno izlazno pojačalo) i drugog stupnja (diferencijalno pojačalo). Glavna svrha analogne linije za kašnjenje je kašnjenje EMG signala i poticaj artefakta između prvog i drugog stupnja. Uvođenjem linije za kašnjenje u standardnom instrumentacijskom pojačalu s tri operacijska pojačala, pokazano je da se poticaj artefakta može otkriti prije nego što se pojavi na izlazu iz pojačala. Na taj način kontrolni sklopovi pojačala imaju dovoljno vremena da onemoguće integrator u diferencijalnom pojačalu, i spriječe nakupljanje naboja u kondenzatoru integratora. Također je pokazano da ova konfiguracija EMG pojačala ima ultra brzo vrijeme oporavka, tako da se može koristiti kao sučelje za kontrolu neuronskih proteza.This paper presents a novel EMG (electromyography) fast recovery amplifier, which can be used as a neural prosthesis control interface. The basis of the proposed circuit is standard three op-amp amplifier with integrator in the negative feed-back loop of the differential amplifier. The Standard three op-amp instrumentation amplifier has been modified by introducing analog delay line between the first stage (differential input - differential output amplifier) and the second stage (differential amplifier). The main purpose of the analog delay line is to delay EMG signal and the stimulus artifact between the first and the second stage. It is shown that by introducing a delay line in the standard three op-amp instrumentation amplifier, stimulus artifact can be detected before it appears at the output of the amplifier. Thus the control circuits of the amplifier have enough time to disable the integrator in the differential amplifier, and prevent charge accumulation in the integrators capacitor. It is also shown that this configuration of the EMG amplifier has ultrafast recovery time, so it can be used as a control interface of the neural prosthesis

"In silico" metode u toksikologiji za procenu bezbednosti lekova

While experimental animal investigation has historically been the most conventional approach conducted to assess drug safety and is currently considered the main method for determining drug toxicity, these studies are constricted by cost, time, and ethical approvals. Over the last 20 years, there have been significant advances in computational sciences and computer data processing, while knowledge of alternative techniques and their application has developed into a valuable skill in toxicology. Thus, the application of in silico methods in drug safety assessment is constantly increasing. They are very complex and are grounded on accumulated knowledge from toxicology, bioinformatics, biochemistry, statistics, mathematics, as well as molecular biology. This review will summarize current state-of-the-art scientific data on the use of in silico methods in toxicity testing, taking into account their shortcomings, and highlighting the strategies that should deliver consistent results, while covering the applications of in silico methods in preclinical trials and drug impurities toxicity testing.Ispitivanja na eksperimentalnim životinjama ne samo da su u prošlosti bila smatrana najkonvencionalnijim pristupom za procenu bezbednosti lekova, već su i trenutno osnovna metoda za utvrđivanje njihove toksičnosti. Međutim, ova ispitivanja su skupa, vremenski zahtevna i za njihovo sprovođenje neophodne su etičke dozvole. Tokom poslednjih 20 godina došlo je do napretka u računarskoj nauci i kompjuterskoj obradi podataka, dok se znanje o alternativnim tehnikama i njihovoj primeni razvilo u dragocenu veštinu u toksikologiji. Stoga, primena in silico metoda u proceni bezbednosti lekova neprestano raste. Ove metode su veoma složene i zasnivaju se na saznanjima iz toksikologije, bioinformatike, biohemije, statistike, matematike i molekularne biologije. Ovaj pregledni rad će rezimirati trenutna naučna saznanja koja se tiču upotrebe in silico metoda u ispitivanju toksičnosti lekova, uzimajući u obzir njihova ograničenja i ističući strategije pomoću kojih se mogu dobiti konzistentni rezultati, sa posebnim osvrtom na primenu in silico metoda u pretkliničkim ispitivanjima i ispitivanjima toksičnosti nečistoća u lekovima

JOURNAL OF AUTOMATIC CONTROL, UNIVERSITY OF BELGRADE, VOL 16:29-32, 2006 © Automatic Classification of Leukocytes

Abstract — This paper presents a novel algorithm for the automatic compilation of differential blood count (DBC), which is based on the direct analysis of a blood smear image and artificial neural networks. The results of the algorithm testing show high sensitivity of the algorithm in leukocyte detection and classification accuracy of 86%. Also, the algorithm enables the detection of potentially falsely classified leukocytes and in that way, with the help of a hematological expert, enables additional increase in the DBC compilation quality

JOURNAL OF AUTOMATIC CONTROL, UNIVERSITY OF BELGRADE, VOL. 19:7-12, 2009© An Improved AC-amplifier for Electrophysiology

Abstract — We present the design, simulation and test results of a new AC amplifier for electrophysiological measurements based on a three op-amp instrumentation amplifier (IA). The design target was to increase the common mode rejection ratio (CMRR), thereby improving the quality of the recorded physiological signals in a noisy environment. The new amplifier actively suppresses the DC component of the differential signal and actively reduces the common mode signal in the first stage of the IA. These functions increase the dynamic range of the amplifier’s first stage of the differential signal. The next step was the realization of the amplifier in a single chip technology. The design and tests of the new AC amplifier with a differential gain of 79.2 dB, a CMRR of 130 dB at 50 Hz, a high-pass cutoff frequency at 0.01 Hz and common mode reduction in the first stage of the 49.8 dB are presented in this paper. Index Terms — AC-amplifier; electrophysiological signals; CMRR; DC offset suppressio

An implementation of movement classification for prosthesis control using custom-made EMG system

Electromyography (EMG) is a well known technique used for recording electrical activity produced by human muscles. In the last few decades, EMG signals are used as a control input for prosthetic hands. There are several multifunctional myoelectric prosthetic hands for amputees on the market, but so forth, none of these devices permits the natural control of more than two degrees of freedom. In this paper we present our implementation of the pattern classification using custom made components (electrodes and an embedded EMG amplifier). The components were evaluated in offline and online tests, in able bodied as well as amputee subjects. This type of control is based on computing the time domain features of the EMG signals recorded from the forearm and using these features as input for a Linear Discriminant Analysis (LDA) classifier estimating the intention of the prosthetic user. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III - 41007

An implementation of movement classification for prosthesis control using custom-made EMG system

Electromyography (EMG) is a well known technique used for recording electrical activity produced by human muscles. In the last few decades, EMG signals are used as a control input for prosthetic hands. There are several multifunctional myoelectric prosthetic hands for amputees on the market, but so forth, none of these devices permits the natural control of more than two degrees of freedom. In this paper we present our implementation of the pattern classification using custom made components (electrodes and an embedded EMG amplifier). The components were evaluated in offline and online tests, in able bodied as well as amputee subjects. This type of control is based on computing the time domain features of the EMG signals recorded from the forearm and using these features as input for a Linear Discriminant Analysis (LDA) classifier estimating the intention of the prosthetic user.</jats:p

Electrotactile Stimulation, A New Feedback Channel for First Responders

This paper presents the early results of research aiming to develop a novel system for unobtrusive and intuitive electrotactile feedback for first responders. The system leverages the multi-pad stimulation technology based on spatiotemporal modulation of the stimuli. Two-point discrimination threshold mapping was performed in potential electrode placement locations, defined from the usability perspective by the first responders in initial co-development sessions. Based on these results a custom electrode design was proposed and validated in six healthy volunteers. Psychometric testing was conducted to determine spatial discrimination between stimuli produced by the multi-pad electrode. The average success rate of 80% indicates that the proposed approach is feasible.The work presented in this paper was funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 883315

A multi-pad electrode based functional electrical stimulation system for restoration of grasp

<p>Abstract</p> <p>Background</p> <p>Functional electrical stimulation (FES) applied via transcutaneous electrodes is a common rehabilitation technique for assisting grasp in patients with central nervous system lesions. To improve the stimulation effectiveness of conventional FES, we introduce multi-pad electrodes and a new stimulation paradigm.</p> <p>Methods</p> <p>The new FES system comprises an electrode composed of small pads that can be activated individually. This electrode allows the targeting of motoneurons that activate synergistic muscles and produce a functional movement. The new stimulation paradigm allows asynchronous activation of motoneurons and provides controlled spatial distribution of the electrical charge that is delivered to the motoneurons. We developed an automated technique for the determination of the preferred electrode based on a cost function that considers the required movement of the fingers and the stabilization of the wrist joint. The data used within the cost function come from a sensorized garment that is easy to implement and does not require calibration. The design of the system also includes the possibility for fine-tuning and adaptation with a manually controllable interface.</p> <p>Results</p> <p>The device was tested on three stroke patients. The results show that the multi-pad electrodes provide the desired level of selectivity and can be used for generating a functional grasp. The results also show that the procedure, when performed on a specific user, results in the preferred electrode configuration characteristics for that patient. The findings from this study are of importance for the application of transcutaneous stimulation in the clinical and home environments.</p