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A small, hermetic, wirelessly-controlled retinal prosthesis was developed for pre-clinical studies in Yucatan mini-pigs. The device was implanted on the outside of the eye in the orbit, and it received both power and data wirelessly from external sources. The prosthesis drove a sub-retinal thin-film array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium...
Entropy, as a measure of randomness in time-varying signals, is widely used in areas such as thermodynamics, statistical mechanics and information theory. This paper investigates the use of two commonly employed entropy measures, namely Wavelet Entropy and Approximate Entropy, as a predictor of tremor reappearance in Essential Tremor patients; the predictor input is a raw surface-electromyographic...
Epidural spinal cord stimulation (ESCS) combined with partial weight bearing therapy (PWBT) has been reported to facilitate recovery of functional walking for individuals after chronic incomplete spinal cord injury. This paper describes a low cost, fully implantable, advanced ESCS stimulator that can be manufactured in a research laboratory for use in small animals. The system is composed of four...
A tissue bath system, to be used as an alternative to complex perfusion chambers, was constructed for use in cardiac electrophysiological studies. This system consists of an acrylic chamber to hold circulating physiological medium such as DMEM, suspended in a water bath warmed by a hot plate. Temperature and pH were controlled to mimic physiological conditions. Rat and porcine cardiac tissues, were...
This paper reports on the preparation and characterization of highly porous platinum electrodes for functional electrical stimulation. Thin-film platinum electrodes were roughened by electrochemical deposition of platinum-copper alloys and subsequent removal of copper using cyclic voltammetry (CV). Prepared samples were characterized by electrochemical impedance spectroscopies (EIS), CVs and long-term...
Steady-state visual evoked potential (SSVEP)-based Brain-Computer Interface (BCI) works on the basis that an attended stimulus shows an enhanced visual evoked response. By examining EEG power at the frequency of the dominant evoked response, we are able to determine which stimulus the subject is attending. However, due to the limited processing capability of human visual system, when presented with...
A wireless multichannel data acquisition system is being designed for ElectroEncephaloGraphy (EEG) recording. The system is based on a custom integrated circuit (ASIC) for signal conditioning, amplification and digitization and also on commercial components for RF transmission. It supports the RF transmission of a 32-channel EEG recording sampled at 1 kHz with a 12-bit resolution. The RF communication...
Electroencephalogram (EEG) is an important component of the pre-surgical evaluation in the treatment of medically intractable epilepsy. However, clinical EEG uses 19 to 32 electrodes that significantly limits its localization ability. Recent development of dense-array recording techniques has suggested that increased spatial sampling rate improves the accuracy of source localization. In the current...
Brain Computer Interface (BCI) systems control the user's environment via his/her brain signals. Brain signals related to motor imagery (MI) have become a widespread method employed by the BCI community. Despite the large number of references describing the MI signal treatment, there is not enough information related to the available programming languages that could be suitable to develop a specific-purpose...
Neuromuscular electrical stimulation (NMES) can alter the functioning of muscles and even assist muscle rehabilitation. In this paper, we evaluate the effect of NMES on the conduction velocity (CV) of the brachial biceps' motor units. We used a linear array of electrodes to acquire electromyographic signals, as different subjects perform isometric voluntary contractions (IVCs), with and without prior...
Magnetic Resonance Electrical Impedance Tomography (MREIT) produces cross-sectional images of a conductivity distribution inside the human body. We use an MRI scanner as a tool to measure induced internal magnetic flux density distributions subject to externally injected currents. Recent experimental MREIT studies demonstrated conductivity image reconstructions of in vivo animal and human subjects...
The Smart Patches and Wearable Band (W-Band) are proposed for comfortable sleep monitoring system which recognizes and diagnoses sleep disorders. By using Planar Fashionable Circuit Board (P-FCB) techniques, the Smart Patches are implemented with the plain fabric patch so that it can have light weight and small size. And the stretchability of the W-Band can achieve user convenience, low manufacturing...
Although deep brain stimulation (DBS) therapy has been achieved, fine tuning on the operational parameters and the equipment are needed in order to make the stimulation treatment more applicable. Thus, the purpose of this study is to design and produce a deep brain stimulation device for DBS experiments for small animals (e.g. rats). Physical size, durability, cost of device and convenience of operation...
Neural oscillations are important features in a working central nervous system, facilitating efficient communication across large networks of neurons. To better study the role of these oscillations in various cognitive processes, and to be able to build clinical applications around them, accurate and precise estimations of the instantaneous frequency and phase are required. Here, we present methodology...
We investigate the use of machine learning methods based on the pre-treatment electroencephalograph (EEG) to predict response to repetitive transcranial magnetic stimulation (rTMS), which is a non-pharmacological form of therapy for treating major depressive disorder (MDD). The learning procedure involves the extraction of a large number of candidate features from EEG data, from which a very small...
This paper considers the achievable reduction in peak voltage across two driving terminals of an RC circuit when delivering charge using a stepped current waveform, comprising a chosen number of steps of equal duration, compared with using a constant current over the total duration. This work has application to the design of neurostimulators giving reduced peak electrode voltage when delivering a...
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...
This study investigated the feasibility of chronically recording descending signals from the rat spinal cord using microwire electrodes. Eight 25μm diameter Pt-Ir microwires were implanted in the dorsolateral rubrospinal tract (RST) bilaterally at the c5 level in each of the four adult Long Evans rats trained for food reach-to-grasp task. Signal stability was assessed by calculating the signal-to-noise...
This paper presents a dry fabric electrode and its characteristics. For long-term physiological signal monitoring, conventional wet type electrode such as an Ag/AgCl electrode may not be sufficient, because captured signal strength degrades over time as its electrolyte dehydrates. Moreover, the electrolyte may cause skin irritation over a period of time. As a complement, a dry electrode can be used...
The reduction of the number of EEG features to give as inputs to epilepsy seizure predictors is a needed step towards the development of a transportable device for real-time warning. This paper presents a comparative study of three feature selection methods, based on Support Vector Machines. Minimum-Redundancy Maximum-Relevance, Recursive Feature Elimination, Genetic Algorithms, show that, for three...
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