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Recordings from thin-film Longitudinal Intra-Fascicular Electrodes (tfLIFE) together with a wavelet-based de-noising and a correlation-based spike sorting algorithm, give access to firing patterns of muscle spindle afferents. In this study we use a point process probability structure to assess mechanical stimulus-response characteristics of muscle spindle spike trains. We assume that the stimulus...
This paper introduces a new method for measuring cortical excitability using an electrical probing stimulus via intracranial electroencephalography (iEEG). Stimuli consisted of 100 single bi-phasic pulses, delivered every 10 minutes. Neural excitability is estimated by extracting a feature from the iEEG responses to the stimuli, which we dub the mean phase variance (PV). We show that the mean PV increases...
We have used two algorithms, wavelet phase coherence (WPC) and modulation index (MI) analysis to study frequency interactions in the human epileptic brain. Quantitative analyses were performed on intracranial electroencephalographic (iEEG) segments from three patients with neocortical epilepsy. Interelectrode coherence was measured using WPC and intraelectrode frequency interactions were analyzed...
Neuroscientists are becoming interested in the application of computational EEG analysis to the identification of ictal onset zones, however, most studies have focused on the localization of ictal onset zones in focal epilepsy. The present study aimed to estimate the ictal onset zone of Lennox-Gastaut syndrome (LGS) with bilaterally synchronous epileptiform discharges from intracranial electroencephalography...
The Driven-Right-Leg (DRL) circuit has been used for about 50 years to reduce interference due to common-mode voltage in biopotential amplifiers in scenarios that range from fixed equipment supplied from power lines to battery-supplied ambulatory monitors, and for systems that use gelled, dry, textile, and capacitive electrodes. However, power-line interference models predict that for isolation amplifiers,...
In this study, we determined the optimal position and direction of a one-channel bipolar electrocardiogram (ECG), used ubiquitously in healthcare. To do this, we developed a three-dimensional (3D) electrophysiological model of the heart coupled with a torso model that can generate a virtual body surface potential map (BSPM). Finite element models of the atria and ventricles incorporated the electrophysiological...
Prosthetic hands are becoming more advanced and gaining degrees-of-freedom similar to their human counterparts. However, the command interface enabling control of these prostheses needs to be improved for more intuitive functional use. One barrier to using electromyographic (EMG) signals as the command interface is measuring independent muscle control sites in the residual limb. Surface electrodes...
In the context of drug resistant partial epilepsy, intra-cerebral electrical stimulation (Deep Brain Stimulation) constitutes one of the means of investigation to locate epileptic volume. This exogenous source can then activate the underlying epileptic networks and generate an electrophysiological reaction. The purpose of this work is to estimate and eliminate the overlapping electrical stimulation...
Vagus nerve stimulation (VNS) is effective for treating epilepsy and depression, and has emerging indications for anxiety and heart failure. However, stimulation-evoked side effects remain a challenge for long-term compliance. We investigated the feasibility of reducing VNS side effects by using a temporally-modified stimulation pattern. In 4 anesthetized canines, we measured changes in both the heart...
A single cuff electrode with multiple-contacts permits fibre selective recording from peripheral nerves. This has been demonstrated in frog nerve in vitro and earth worm before. In this paper we apply this method successfully to the peripheral median nerve of pig in vivo. Compound action potentials (CAPs) were electrically excited at the median nerve close to the wrist of the forelimb. The CAPs were...
The administration of the anesthetic agents is known to alter the electroencephalogram (EEG) signal significantly with the brain being their primary target. In this study, we analyzed the EEG recorded from six ASA I/II patients undergoing a 1–2 hour surgery. The EEG was collected before and during induction, maintenance and recovery of anesthesia using the 10/20 lead-system. A combination of fentanyl...
This paper describes a novel sensing approach for reducing power requirements of implantable vestibular prostheses. A passive, microfabricated polymeric inertial sensor for detecting angular head rotations based on the biomechanics of the human semicircular canal is described. Angular head motion is coded by deflection of a highly compliant capacitor plate placed in parallel with a rigid reference...
After spinal cord injury, electrical stimulation of the roots inside the spinal column at the level of the cauda equina is a safe and effective way to regain some degree of control over lower body function, e.g. bladder and bowel management and leg movement. The success of current systems used for so-called intrathecal stimulation is limited by the low number of stimulation channels, which are in...
The clinical efficacy of electro-therapy in the treatment of chronic wounds is currently debated, and a in-vivo evaluation of stimulation parameters will provide the statistical evidence needed to direct clinical guidelines. A low-cost, wearable electrical stimulation bandage has been developed for use with an established rat ischemic wound model. The bandage consists of a user-programmable stimulator...
In this paper we evaluate the physiological performance of a silver-silver chloride dry electrode with bristle (B-Electrode) in recording EEG data. For this purpose, we compare the performance of the bristle electrode in recording EEG data with the standard wet gold-plated cup electrode (G-Electrode) using two different brain state change tasks including resting condition with eyes-closed and performing...
With more clinical trials proving viability of visual prosthesis follows the demand for higher resolution devices. As the number of electrodes increases, due to surgical difficulties, it is preferred to keep their length short by placing the implant close to the stimulation site, where there are considerable constraints on device size. On the contrary, the physical volume of the implant generally...
A CMOS-based flexible retinal stimulator equipped with bullet-shaped bulk Pt electrodes was fabricated and demonstrated. We designed a new CMOS unit chip with an on-chip stimulator, single- and multi-site stimulation modes, and monitoring functions. We have developed a new structure and packaging process of flexible retinal stimulator with bullet-type bulk Pt electrode. We have confirmed the retinal...
This work presents a Brain-Computer Interface (BCI) based on Steady State Visual Evoked Potentials (SSVEP), using higher stimulus frequencies (>30 Hz). Using a statistical test and a decision tree, the real-time EEG registers of six volunteers are analyzed, with the classification result updated each second. The BCI developed does not need any kind of settings or adjustments, which makes it more...
Ventricular arrhythmias represent one of leading causes for sudden cardiac death, a significant problem in public health. Noninvasive imaging of cardiac electric activities associated with ventricular arrhythmias plays an important role in better our understanding of the mechanisms and optimizing the treatment options. The present study aims to rigorously validate a novel three-dimensional (3-D) cardiac...
Sleep has profound effects on the physical and mental well-being of an individual. The National Institutes of Health (NIH) Sleep Disorder Research Plan gives particular emphasis to non-invasive sleep monitoring methods. Older adults experience sleep fragmentation due to sleep disorders. Unobtrusive non-contact monitoring can be the only realistic solution for long term home-based sleep monitoring...
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