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Recently, implantable devices have become widely used in neural prostheses because they eliminate endemic drawbacks of conventional percutaneous neural interface systems. However, there are still several issues to be considered: low-efficiency wireless power transmission; wireless data communication over restricted operating distance with high powe...
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... a shielding material, a ferrite plate with a 2-mm thickness was attached to the bottom of the wireless power receiving coil to minimize the degradation of efficiency and prevent direct heat damage to susceptible components behind the wireless power receiving coil [42]. Other characteristics of the wireless power transmission coils are shown in Table 2. ...
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Citations
... • Stimulation and recording the neural activity in the peripheral nervous system [22]; • Acquisition of neural signals for the control of motor exoprostheses [23,24]; • Stimulation of the optic nerve for visual prosthesis [25]; • Electrical stimulation of the nerves, for the restoration of motor functions [26,27]. There is a major inconvenience related to the cuff microelectrodes: this type of electrodes cannot acquire signals from a certain motor fascicle of the nerve, and, consequently, cannot provide the required selectivity for a performant arm prosthesis. ...
There is great interest in the development of prosthetic limbs capable of complex activities that are wirelessly connected to the patient’s neural system. Although some progress has been achieved in this area, one of the main problems encountered is the selective acquisition of nerve impulses and the closing of the automation loop through the selective stimulation of the sensitive branches of the patient. Large-scale research and development have achieved so-called “cuff electrodes”; however, they present a big disadvantage: they are not selective. In this article, we present the progress made in the development of an implantable system of plug neural microelectrodes that relate to the biological nerve tissue and can be used for the selective acquisition of neuronal signals and for the stimulation of specific nerve fascicles. The developed plug electrodes are also advantageous due to their small thickness, as they do not trigger nerve inflammation. In addition, the results of the conducted tests on a sous scrofa subject are presented.
... Prior reported sense and stimulation systems have focused on a variety of problems including wireless operation [8], large channel count [9], and operation in an implantable device [10]. Each of these solutions have benefits for the use case they are designed for; however, none are appropriate for the general neuroscience research user. ...
... Previous solutions such as [15] have focused on wireless implementations, been limited to only stimulation [16] or sensing [17] capabilities, or have required custom components [8]- [10]. These solutions have a variety of challenges for the average user including data throughput limitations with wireless implementations, sensing limitations, and part availability challenges. ...
... The cuff electrodes we developed in the previous study [21] were used as interfaces between the peripheral nerves and the four-channel neurostimulator. Cuff electrodes were one of the important interfaces to connect nerves and machines and have been actively developed and applied to stimulate nerves in humans or animals [26]. The two cuff electrodes from the four-channel neurostimulator were connected to the tibial and peroneal nerves, respectively, to control the dorsal/plantar flexion of the ankle joint. ...
A wirelessly powered four-channel neurostimulator was developed for applying selective Functional Electrical Stimulation (FES) to four peripheral nerves to control the ankle and knee joints of a rat. The power of the neurostimulator was wirelessly supplied from a transmitter device, and the four nerves were connected to the receiver device, which controlled the ankle and knee joints in the rat. The receiver device had functions to detect the frequency of the transmitter signal from the transmitter coil. The stimulation site of the nerves was selected according to the frequency of the transmitter signal. The rat toe position was controlled by changing the angles of the ankle and knee joints. The joint angles were controlled by the stimulation current applied to each nerve independently. The stimulation currents were adjusted by the Proportional Integral Differential (PID) and feed-forward control method through a visual feedback control system, and the walking trajectory of a rat’s hind leg was reconstructed. This study contributes to controlling the multiple joints of a leg and reconstructing functional motions such as walking using the robotic control technology.
... When the implant is in sleep mode (no stimulation outputs), the buck DC/DC of the LTC3331 converts the high voltage energy (between 6 V and 15 V) received on the receiver coil to charge the battery. If the link is inactive the fully charged battery can deliver 10 The QI standard based commercial inductive transmitter (STEVAL-ISB047V1) is used for wireless power transmission. The transmitter can deliver up to 5 W power with a carrier frequency of 126.7 kHz. ...
This paper presents a fully-implantable closed-loop opto-electro stimulation interface for motor neuron disease studies, designed for experiments with freely moving rodents. A low power consumption Bluetooth data link is used to wirelessly control 64 opto-electro stimulation channels and receive neural recording data. The implant is powered by a wirelessly rechargeable lithium-ion battery, which can support 2.5 hours continuous operation with a stimulation output up to 10 mA. The battery is recharged using a QI standard wireless inductive power link, which can deliver >100mW power at a distance of 2 cm. The total size of the implant system is 29 mm × 20 mm × 13 mm. Its performance is compared with the state-of-the-art.
... Although IWMDs are commonly assembled with multiple COTS components, in [75], the authors demonstrated a hermetically sealed wireless implantable neural interface realized using multiple COTS devices. The application consists of four key COTS system blocks for recording, stimulating, wireless telemetry and a power supply. ...
Over the past decade, there has been exponential growth in the per capita rate of medical patients around the world, and this is significantly straining the resources of healthcare institutes. Therefore, the reliance on smart commercial off-the-shelf (COTS) implantable wireless medical devices (IWMDs) is increasing among healthcare institutions to provide routine medical services, such as monitoring patients’ physiological signals and the remote delivery of therapeutic drugs. These smart COTS IWMDs reduce the necessity of recurring visits of patients to healthcare institutions and also mitigate physical contact, which can minimize the possibility of any potential spread of contagious diseases. Furthermore, the devices provide patients with the benefit of recuperating in familiar surroundings. As such, low-cost, ubiquitous COTS IWMDs have engendered the proliferation of telemedicine in healthcare to provide routine medical services. In this paper, a review work on COTS IWMDs is presented at a macro level to discuss the history of IWMDs, different networked COTS IWMDs, health and safety regulations of COTS IWMDs and the importance of organized procurement. Furthermore, we discuss the basic building blocks of IWMDs and how COTS components can contribute to build these blocks over widely researched custom-built application-specific integrated circuits.
... The acquisition of neural electrical signals to control motor prostheses [6,7]; • ...
... • The acquisition of neural electrical signals to control motor prostheses [6,7]; ...
In this article, we present our research achievements regarding the development of a remote sensing system for motor pulse acquisition, as a first step towards a complete neuroprosthetic arm. We present the fabrication process of an implantable electrode for nerve impulse acquisition, together with an innovative wirelessly controlled system. In our study, these were combined into an implantable device for attachment to peripheral nerves. Mechanical and biocompatibility tests were performed, as well as in vivo testing on pigs using the developed system. This testing and the experimental results are presented in a comprehensive manner, demonstrating that the system is capable of accomplishing the requirements of its designed application. Most significantly, neural electrical signals were acquired and transmitted out of the body during animal experiments, which were conducted according to ethical regulations in the field.
... Each of the units described above is generic and different wireless neural signal recording systems have similar and corresponding functions. They could be divided into four schemes according to the degree of system integration: (1) modular distributed [19,[67][68][69][70], (2) stacked [24,26,71,72], (3) integrated [32,[73][74][75][76][77][78][79], and (4) ultracompact [80][81][82][83][84]. In addition, there are differences in miniaturization, lightweight, and functional expansion between different schemes, which will be described in detail below. ...
... To address this issue, some researchers have proposed a method of dividing the PCB board into modules, connecting the modules with flexible flat cable, then folding to reduce the area of PCB [22,71]. The 3D stack method is a representative method for reducing system size [24,26,72,86]. Figure 3(b) shows a typical stacked system consisting of the front-end chip (RHD2132, Intan Technologies), FPGA (Spartan-6, Xilinx company), radio chip (nRF24L01, Nordic ...
... In recent years, researchers have made great progress in miniaturization, high channel count, and low power consumption using CMOS processing technology [32,[73][74][75][76][77][78][79]. Table 2 [16,23,71,72,74,77,83,87,88] compares recent chips for implantable BCI using COMS technology. Although the latest CMOS process level can reach 7 nm, the signal preprocessing chip is an analog application-specific integrated circuit (ASIC) for BCI, which places more emphasis on the quality of signal processing, such as precision, reliability, and stability. ...
An implantable brain-computer interface (BCI) has proven to be effective in the field of sensory and motor function restoration and in the treatment of neurological disorders. Using a BCI recording system, we can transform current methods of human interaction with machines and the environment, especially to help those with cognitive and mobility disabilities regain mobility and reintegrate into society. However, most reported work has focused on a simple aspect of the whole system, such as electrodes, circuits, or data transmission, and only a very small percentage of systems are wireless. A miniature, lightweight, wireless, implantable microsystem is key to realizing long-term, real-time, and stable monitoring on freely moving animals or humans in their natural conditions. Here, we summarize typical wireless recording systems, from recording electrodes, processing chips and controllers, wireless data transmission, and power supply to the system-level package for either epicortical electrocorticogram (ECoG) or intracortical local field potentials (LFPs)/spike acquisition, developed in recent years. Finally, we conclude with our vision of challenges in next-generation wireless neuronal recording systems for chronic and safe applications.
... The multi-channel neural interfaces basically have diverse designs depending on the implant sites (brain, spinal cord, peripheral nerve, and vagus nerve), and each neural electrode is commonly connected to a pre-amplifier device regardless of whether it is wire-or wireless-driven [11][12][13][14]. For the connection between the neural electrode and the pre-amplifier device, it is common to use wire bonding or an unsealed connector integrated on a PCB and to mainly use the form of encapsulating the connection part and pre-amplifier device with a biocompatible polymer [15][16][17][18][19]. However, the reason to use the small packaging configuration with the biocompatible polymer can be inferred from the spatial limitation of the implantation site. ...
... The multi-channel neural interfaces basically have diverse designs depending on the implant sites (brain, spinal cord, peripheral nerve, and vagus nerve), and each neural electrode is commonly connected to a preamplifier device regardless of whether it is wire-or wireless-driven [11][12][13][14]. For the connection between the neural electrode and the pre-amplifier device, it is common to use wire bonding or an unsealed connector integrated on a PCB and to mainly use the form of encapsulating the connection part and pre-amplifier device with a biocompatible polymer [15][16][17][18][19]. However, the reason to use the small packaging configuration with the biocompatible polymer can be inferred from the spatial limitation of the implantation site. ...
This paper proposed and verified the use of polymer-based packaging to implement the chronic implantation of neural interfaces using a combination of a commercial thermal epoxy and a thin parylene film. The packaging’s characteristics and the performance of the vulnerable interface between the thermal epoxy layer and polyimide layer, which is mainly used for neural electrodes and an FPCB, were evaluated through in vitro, in vivo, and acceleration experiments. The performance of neural interfaces—composed of the combination of the thermal epoxy and thin parylene film deposition as encapsulation packaging—was evaluated by using signal acquisition experiments based on artificial stimulation signal transmissions through in vitro and in vivo experiments. It has been found that, when commercial thermal epoxy normally cured at room temperature was cured at higher temperatures of 45 °C and 65 °C, not only is its lifetime increased with about twice the room-temperature-based curing conditions but also an interfacial adhesion is higher with more than twice the room-temperature-based curing conditions. In addition, through in vivo experiments using rats, it was confirmed that bodily fluids did not flow into the interface between the thermal epoxy and FPCB for up to 18 months, and it was verified that the rats maintained healthy conditions without occurring an immune response in the body to the thin parylene film deposition on the packaging’s surface.
... This implies a complex waveform design on the synchronous output and an increasing number of wires between the stimulus generator and the electrode contacts (poles). A programmable multidimensional stimulus waveform provides the opportunity to conduct research on artificial-to-natural interfaces in order to achieve an efficient and minimally aggressive activation [35][36][37][38]. In contrast, the vast majority of the solutions that have been tested on humans have been based on centralized implants through which the wires output to monopolar or bipolar electrodes [39][40][41]. ...
Peripheral Nerve Stimulation (PNS) is a promising approach in functional restoration following neural impairments. Although it proves to be advantageous in the number of implantation sites provided compared with intramuscular or epimysial stimulation and the fact that it does not require daily placement, as is the case with surface electrodes, the further advancement of PNS paradigms is hampered by the limitation of spatial selectivity due to the current spread and variations of nerve physiology. New electrode designs such as the Transverse Intrafascicular Multichannel Electrode (TIME) were proposed to resolve this issue, but their use was limited by a lack of innovative multichannel stimulation devices. In this study, we introduce a new portable multichannel stimulator—called STIMEP—and implement different stimulation protocols in rats to test its versatility and unveil the potential of its combined use with TIME electrodes in rehabilitation protocols. We developed and tested various stimulation paradigms in a single fascicle and thereafter implanted two TIMEs. We also tested its stimulation using two different waveforms. The results highlighted the versatility of this new stimulation device and advocated for the parameterizing of a hyperpolarizing phase before depolarization as well as the use of small pulse widths when stimulating with multiple electrodes.
... On the other hand, most state-of-the-art devices that provide wireless radio-frequency (RF) communication, are either head-or back-mounted [6], designed for high data rate applications [19] or use integrated solutions [8]. Low frequency links such as Near-Field-Communication (NFC) used in [9] or technologies utilizing the 402 to 405 MHz MICS band used in [11] require larger external or intra-PCB coils which exceed the area constraints of implantable systems in small rodent models. Ultra-High-Frequency (UHF) technologies permit the use of compact ceramic chip antennas that are more suited for fully implantable devices. ...
