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In the context of functional electrical stimulation of peripheral nerves, the control of a specific motor or sensory functions may need selective stimulation to target the desired effect without others. In implanted stimulation, spatial selectivity is obtained using multipolar CUFF electrodes with specific spread of the current over each contact. Furthermore, electrical stimulation recruits large...
Direct electrical stimulation (DES) at 60 Hz is used to perform real-time functional mapping of the brain during wide-awake neurosurgery. The electrophysiological effects of DES are largely unknown, locally and at a more remote distance. Here, by lowering the DES frequency to 10 Hz and by using a differential recording mode of electro-corticographic (ECoG) signals to improve the focality, we were...
Electrode designs and strategies for electroneurogram recordings are often tested first by computer simulations and then by animal models, but they are rarely implanted for long-term evaluation in humans. The models show that the amplitude of the potential at the surface of an axon is higher in front of the nodes of Ranvier than at the internodes; however, this has not been investigated through in...
This paper presents an original method to emulate a single fiber action potential in a quasi-infinite conductive volume, suitable for reproducible testing of bio-potential recording systems. The model is accurate for reproducing the biopotential even for a small electrode to fiber radial distances. Established current activities of axon is used and programmed in the developed FPGA-based instrument,...
This paper describes the integration of computational models of the cardiovascular system, the cardiac electrical activity and the baroreceptor reflex of the autonomic nervous system, with a model representing vagal nerve stimulation (VNS). Sensitivity analyses are performed in order to find the model parameters that produce significant effects on heart rate (chronotropic effect). The most significant...
We introduce a new approach for the investigation of multipolar selective neural stimulation. We aim at comparing existing solutions from the literature and innovate in this field with advanced strategies. We have developed a multichannel stimulator, Stim'ND, which allows us to control independently the parameters of complex stimulation profiles of 12 channels for a large number of stimulating current...
The task of distinguishing nerve type for the activity acquired using the multi-electrode cuff presents a big interest in the possible applications of prosthesis control or functional electrical stimulation. In this paper, a method to evaluate the maximum expected performances of filters using two-dimensional spectral analysis is presented and tested on simulated extracellular potentials. These later...
Control systems design may be a difficult task when the system to be controlled is complex, poorly understood, and with limited observability. This is often the case of biological or physiological systems. In this paper, we present a model-based control design framework, which is adapted to the design of medical devices. This framework couples a control module, based on a classical PID controller,...
A method for enhancing the noise-power tradeoff of front-end amplifiers in parallel recording applications is proposed. The circuit uses shared-input transconductance amplifiers and differential readout to attenuate correlated noise between parallel outputs, resulting in significant supply current savings without noise penalty. Also, a method for reducing the remaining noise with little power penalty...
Neural recording is one of the main issues to be addressed in order to allow closed-loop functional electrical stimulation systems. Because each fascicle in nerves carry specific information, new sensors providing high spatial selectivity are required for chronic implantable devices. This work aims at evaluating the feasibility of a new device using a highly spatial-selective multi-contact cuff electrode...
In the context of functional electrical stimulation, neural recording is one of the main issues. For instance, the control of the limbs in people with motor deficiencies needs information about the muscle lengths and speeds that can be extracted from electroneurograms (ENG) carried on afferent peripheral nerves. The aim of this study is to propose an non-invasive and spatial-selective electrode (because...
In the context of functional electrical stimulation (FES), it would be of great interest to get reliable sensitive information directly from the nerve signals. To achieve the chronic recording of electrical activity of the axons it is necessary to develop the electrode and the associated implantable integrated circuit ASIC. In this paper, we have proposed a novel design of multipolar cuff electrodes...
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