Kevin Lloyd Kilgore

MetroHealth Medical Center · Orthopaedics

This feasibility study tested the capability of high frequency stimulation (HFS) to block muscle contractions elicited by electrical stimulation of the same nerve proximally. During a tendon lengthening surgery in the forearm, the anterior interosseous nerve (AIN) was exposed. A specialized nerve cuff electrode was placed around the nerve, and a st...

Estimating blood pressure (BP) values from physiological signals (e.g., photoplethysmogram (PPG)) using deep learning models has recently received increased attention, yet challenges remain in terms of models' generalizability. Here, we propose taking a new approach by framing the problem as tracking the “changes” in BP over an interval, rather tha...

Following spinal cord injury (SCI), intact neural resources undergo widespread reorganization within the brain. Animal models reveal motor cortical representations devoted to spared muscles above injury expand at the expense of territories occupied by weaker muscles. In this study, we investigated whether motor representations are similarly reorgan...

Objective: Corticospinal inhibitory mechanisms are relevant to functional recovery but remain poorly understood after spinal cord injury (SCI). Post-injury characteristics of contralateral silent period (CSP), a measure of corticospinal inhibition evaluated using transcranial magnetic stimulation (TMS), is inconsistent in literature. We envisioned...

This chapter introduces electrical nerve block of peripheral nerves, a relatively new area of interest in the biomedical and neural engineering world. The application of electrical currents through specific waveforms and electrodes have the ability to produce a localized axonal block. This type of block would be clinically useful in diseases charac...

Pulse arrival time (PAT), evaluated from electro-cardiogram (ECG) and photoplethysmogram (PPG) signals, has been widely used for cuff-less blood pressure (BP) estimation due to its high correlation with BP. However, the question of whether filtering the PPG signal impacts the extracted PAT values and consequently, the correlation between PAT and BP...

Brain-machine interfaces have shown promise in extracting upper extremity movement intention from the thoughts of nonhuman primates and people with tetraplegia. Attempts to restore a user's own hand and arm function have employed functional electrical stimulation (FES), but most work has restored discrete grasps. Little is known about how well FES...

The application of direct current (DC) produces a rapid and reversible nerve conduction block. However, prolonged injection of charge through a smooth platinum electrode has been found to cause damage to nervous tissue. This damage can be mitigated by incorporating high-capacitance materials (HCM) (e.g., activated carbon or platinum black) into ele...

Study design: A multisite, randomized, controlled, double-blinded phase I/II clinical trial. Objective: The purpose of this clinical trial is to evaluate the safety, feasibility and efficacy of pairing noninvasive transcranial direct current stimulation (tDCS) with rehabilitation to promote paretic upper extremity recovery and functional indepen...

This paper presents a new solution that enables the use of transfer learning for cuff-less blood pressure (BP) monitoring via short duration of photoplethysmogram (PPG). The proposed method estimates BP with low computational budget by 1) creating images from segments of PPG via visibility graph (VG), hence, preserving the temporal information of t...

In this paper, we introduce PulseLab, a comprehensive MATLAB toolbox that enables estimating the blood pressure (BP) from electrocardiogram (ECG) and photoplethysmogram (PPG) signals using pulse wave velocity (PWV)-based models. This universal framework consists of 6 sequential modules, covering end-to-end procedures that are needed for estimating...

Deep learning-based cuff-less blood pressure (BP) estimation methods have recently gained increased attention as they can provide accurate BP estimation with only one physiological signal as input. In this paper, we present a simple and effective method for cuff-less BP estimation by training a small-scale convolutional neural network (CNN), modifi...

Although vagus nerve stimulation (VNS) can be used to reduce heartrate by enhancing parasympathetic activity, a fully controllable intervention would also require a method for downregulating parasympathetic activity. A direct current (DC) block can be applied to a nerve to block its action potential conduction. This nerve block can be used to downr...

Implantable motor neuroprostheses can restore functionality to individuals with neurological disabilities by electrically activating paralyzed muscles in coordinated patterns. The typical design of neuroprosthetic systems relies on a single multi-use device, but this limits the number of stimulus and sensors channels that can be practically impleme...

Objective: Electrical nerve block offers the ability to immediately and reversibly block peripheral nerve conduction and would have applications in the emerging field of bioelectronics. Two modalities of electrical nerve block have been investigated - kilohertz frequency alternating current (KHFAC) and direct current (DC). KHFAC can be safely deli...

This paper reports on a low-power readout IC (ROIC) for high-fidelity recording of the photoplethysmogram (PPG) signal. The system comprises a highly reconfigurable, continuous-time, ${2^{nd}}$ -order, incremental delta-sigma modulator (I ${\Sigma\Delta}$ M) as a light-to-digital converter (LDC), a 2-channel 10b light-emitting diode (LED) driver...

Objective: To determine if the motor response on the stimulated manual muscle test (SMMT) in muscles with a grade 0 motor score on the manual muscle test (MMT) can differentiate lower motor neuron (LMN) from upper motor neuron (UMN) injury based on the presence of spontaneous activity (SA) with needle EMG. Design: Prospective Study. Participant...

Background: Kilohertz frequency alternating currents (KHFAC) produce rapid nerve conduction block of mammalian peripheral nerves and have potential clinical applications in reducing nerve hyperactivity. However, there are no experimental measurements of the block inception time (BIT) for the complete block of mammalian motor axons, i.e. the time f...

Aim: To validate the use of motor activation thresholds (MoT) to titrate stimulation amplitudes for spinal cord stimulation in rodent models. Methods: We recorded thresholds for MoT and sciatic compound action potentials in ten Sprague-Dawley rats implanted with epidural electrodes. Strength duration curves were fitted to the threshold values. Resu...

Background: Kilohertz frequency alternating current (KHFAC) waveforms reversibly block conduction in mammalian peripheral nerves. The initiation of the KHFAC produces nerve activation, called the onset response, before complete block occurs. An amplitude ramp, starting from zero amplitude, is ineffective in eliminating this onset activity. We post...

This article describes the application of neuromodulation in different ways to motor recovery, to replace lost function, or to improve function of organ systems for those who have experienced spinal cord injury or stroke. Multiple devices have been developed and are currently available for use whereas others are still in the experimental stage. Mul...

Direct current (DC) nerve block has been shown to provide a complete block of nerve conduction without unwanted neural firing. Previous work shows that high capacitance electrodes can be used to safely deliver DC block. Another way of delivering DC safely is through a separated interface nerve electrode (SINE) such that any reactive species that ar...

Background: Kilohertz frequency alternating currents (KHFAC) produce rapid nerve conduction block of mammalian peripheral nerve and have potential clinical applications in reducing peripheral nerve hyperactivity. The experimental investigation of KHFAC nerve block requires a robust output measure and this has proven to be the block threshold (BT),...

Neuromuscular electrical stimulation (NMES) of paralyzed muscles can be used to restore or replace motor function in individuals who have upper motor neuron damage from causes such as stroke or spinal cord injury (SCI). In some conditions, such as stroke or incomplete SCI, NMES may be part of a therapy regimen that helps restore volitional movement...

The Cleveland Neural Engineering Workshop (NEW) is a biennial meeting started in 2011 as an “unconference” to bring together leaders in the neural engineering and related fields. Since the first iteration of the meeting, NEW has evolved from “just getting together” to a more important purpose of creating, reviewing, and promoting a uniform strategi...

Background: Spinal cord injury (SCI) occurring at the cervical levels can result in significantly impaired arm and hand function. People with cervical-level SCI desire improved use of their arms and hands, anticipating that regained function will result in improved independence and ultimately improved quality of life. Neuroprostheses provide the mo...

Background: More than half of all individuals who sustain a spinal cord injury (SCI) experience some degree of impairment in the upper limb. Functional use of the arm and hand is of paramount importance to these individuals. Fortunately, the number of clinical trials and advanced interventions targeting upper limb function are increasing, generatin...

Aims: Nerve conduction block using implanted electrodes is being used increasingly for clinical applications. Alternatively, non-invasive electrical nerve block would be beneficial for applications including pain block and muscle spasticity. Here we developed a novel means of non-invasive electrical nerve conduction blockade – transcutaneous direct...

Introduction: Electrical nerve block uses electrical waveforms to block action potential propagation. Materials & methods: Two key features that distinguish electrical nerve block from other nonelectrical means of nerve block: block occurs instantly, typically within 1 s; and block is fully and rapidly reversible (within seconds). Results: App...

Objective: Application of Kilohertz Frequency Alternating Current (KHFAC) waveforms can result in nerve conduction block that is induced in less than a second. Conduction recovers within seconds when KHFAC is applied for about 5 - 10 minutes. This study investigated the effect of repeated and prolonged application of KHFAC on rat Sciatic nerve wit...

Objective Our goal was to determine if pairing transcranial direct current stimulation (tDCS) with rehabilitation for two weeks could augment adaptive plasticity offered by these residual pathways to elicit longer-lasting improvements in motor function in incomplete spinal cord injury (iSCI). Design Longitudinal, randomized, controlled, double-bli...

Described herein are methods of treating various neurological disorders using electrical nerve conduction block (ENCB) without causing electrochemical damage. Examples of the various neurological disorders can include pain, muscle spasticity, hyperhidrosis, vertigo, sialorrhea, or the like. The methods can include placing an electrode contact in el...

Objective: To examine the prevalence of joint contractures in the upper limb and association with voluntary strength, innervation status, functional status, and demographics in a convenience sample of individuals with cervical spinal cord injury to inform future prospective studies. Design: Cross-sectional convenience sampled pilot study. Setting:...

Motor neuroprostheses can provide standing, stepping, and walking functions for individuals with hemiplegia or paraplegia; and can provide grasping and reaching functions for individuals with tetraplegia. Motor neuroprostheses are designed to give the user control of the patterned electrical activation of his or her muscles. There are over 30 diffe...

Background: Previous studies have demonstrated the presence of intact axons across a spinal cord lesion, even in those clinically diagnosed with complete spinal cord injury (SCI). These axons may allow volitional motor signals to be transmitted through the injury, even in the absence of visible muscle contraction. Objective: To demonstrate the p...

This paper reports on the feasibility of recording the photoplethysmogram (PPG) signal subcutaneously from muscle groups in minimally invasive fashion as a step toward chronic implantation. A system has been developed that records the PPG signals in the reflective mode using a portable sensor board interfaced with a battery-powered main board for c...

This is the granted US patent for Application US 14/408,017. Devices and methods for blocking signal transmission through neural tissue. One step of a method includes placing a therapy delivery device into electrical communication with the neural tissue. The therapy delivery device includes an electrode contact having a high charge capacity materi...

Charge-balanced direct current (CBDC) nerve block can be used to block nerve conduction in peripheral nerves. Previous work demonstrated that the CBDC waveform could be used to achieve a 10% duty cycle of block to non-block repeatedly for at least two hours. We demonstrate that the duty cycle of this approach can be significantly increased by utili...

Scientific advances are increasing the options for improved upper limb function in people with cervical level spinal cord injury (SCI). Some of these interventions rely on identifying an aspect of paralysis that is not uniformly assessed in SCI: the integrity of the lower motor neuron (LMN). SCI can damage both the upper motor neuron and LMN causin...

This is the granted US patent for Application US 14/754,960 One aspect of the present disclosure relates to a system that can provide an electric waveform for neural stimulation or nerve block. The system can include a first circuit component configured to provide a self-oscillating, voltage-boosted electric waveform. In some instances, the first...

Implantable neuroprostheses are an emerging technology that have the potential to restore significant function to individuals who have become disabled due to trauma or disease. Neuroprostheses deliver electrical current to the neuromuscular system and/or record electrical signals from the neuromuscular system. The potential of neuroprostheses to re...

Spinal cord injury in the cervical cord can result in paralysis of all four extremities (tetraplegia). A motor neuroprosthesis can be used to stimulate the paralyzed muscles of the arm and hand to produce coordinated grasping and reaching functions for these patients. The user of the neuroprosthesis has real-time control of the stimulated function...

Described herein are methods of treating various neurological disorders using electrical nerve conduction block (ENCB) without causing electrochemical damage. Examples of the various neurological disorders can include pain, muscle spasticity, hyperhidrosis, vertigo, sialorrhea, or the like. The methods can include placing an electrode contact in el...

Direct current (DC) can briefly produce a reversible nerve conduction block in acute experiments. However, irreversible reactions at the electrode–tissue interface have prevented its use in both acute and chronic settings. A high capacitance material (platinum black) using a charge-balanced waveform was evaluated to determine whether brief DC block...

Kilohertz frequency spinal cord stimulation (KHFSCS) is an emerging therapy for treating refractory neuropathic pain. Although KHFSCS has the potential to improve the lives of patients experiencing debilitating pain, its mechanisms of action are unknown and thus it is difficult to optimize its development. Therefore, the goal of this study was to u...

A method of blocking signal transmission through a nerve with reduced onset activity includes applying an HFAC to an axon of a nerve to block the transmission of signals through the axon. The method may also include applying a direct current (DC) to the axon, increasing the amplitude of the DC over time to a predetermined amplitude, applying the HF...

Notice of Allowance on 2016/03/10. Patent number being issued. Devices and methods for blocking signal transmission through neural tissue. One step of a method includes placing a therapy delivery device into electrical communication with the neural tissue. The therapy delivery device includes an electrode contact having a high charge capacity mate...

Example adjustable electrodes are described. One example adjustable electrode includes two or more contacts configured to selectively deliver high frequency alternating current (HFAC) to a nerve in an amount sufficient to produce an HFAC nerve conduction block in the nerve. The example adjustable electrode also includes a logic configured to select...

>>> OBJECTIVE <<< Kilohertz frequency alternating current (KHFAC) waveforms have been shown to provide peripheral nerve conductivity block in many acute and chronic animal models. KHFAC nerve block could be used to address multiple disorders caused by neural over-activity, including blocking pain and spasticity. However, one drawback of KHFAC block...

Spinal cord injuries (SCI) can disrupt communications between the brain and the body, resulting in loss of control over otherwise intact neuromuscular systems. Functional electrical stimulation (FES) of the central and peripheral nervous system can use these intact neuromuscular systems to provide therapeutic exercise options to allow functional re...

Nerve block can eliminate spasms and chronic pain. Kilohertz frequency alternating current (KHFAC) produces a safe and reversible nerve block. However, KHFAC-induced nerve block is associated with an undesirable onset response. Optical inhibition using infrared (IR) laser light can produce nerve block without an onset response, but heats nerves. Co...

Objective To develop and apply an implanted neuroprosthesis to restore arm and hand function to individuals with high level tetraplegia Design Case study. Setting Clinical research laboratory. Participants Two individuals with spinal cord injuries at or above the C4 motor level. Interventions The individuals were each implanted with two stimula...

Patent 9,119,966 issued on 2015/09/01. GRANTED on 2015/04/29. Full utility patent 14/275,822 was filed on 2014/05/12. One aspect of the present disclosure relates to a system that can provide an electric waveform for neural stimulation or nerve block. The system can include a first circuit component configured to provide a self-oscillating, voltag...

>>> OBJECTIVE <<< Kilohertz Frequency Alternating Current (KHFAC) waveforms are being evaluated in a variety of physiological settings because of their potential to modulate neural activity uniquely when compared to frequencies in the sub-kilohertz range. However, the use of waveforms in this frequency range presents some unique challenges regardin...

PROBLEM: Kilohertz-Frequency AC (KHFAC) waveforms can have unintended direct current (DC) contaminations which may be dangerous to neural tissue or produce unexpected effects of nerve block or neural stimulation. GOALS: 1.Determine offset voltages resulting from off-the-shelf stimulators providing current-and voltage-controlled kHz waveforms. 2.Co...

This chapter discusses the use of sensors in motor neuroprostheses, with a focus on the use of implantable sensors and sensor networks. The chapter reviews the unique requirements that motor neuroprostheses place on the use of sensors. The variety of sensor modalities that have been utilized are reviewed, including sensors used for command control...

GOALS: 1.Determine if the KHFAC onset response can be significantly reduced using multi-phased direct current (mpDC). 2.Find best parameters for a combined KHFAC+mpDC nerve block in an acute randomized study. 3.Assess if repeated application of this combined KHFAC+mpDC nerve block changes nerve conduction post block. RESULTS: 1.KHFAC onset respo...

...… Link: http://neuro.embs.org/files/2013/0654_FI.pdf ......... ................. ELECTRIC nerve block with applications ranging from blocking pain to spasticity has been achieved with a variety of waveforms in the past. Two of the most widely studied are High-Frequency Alternating Current in the kilohertz range (KHFAC) and direct current (DC) si...

GOALS: 1.Evaluate KHFAC PN Block with chronically implanted, human-quality electrodes. 2.Determine chronic stability of parameters to achieve KHFAC PN Block for Bladder Voiding. 3.Provide electric-only bladder care to animals with chronic-SCI using KHFAC Pudendal Nerve block 4.Verify absence of adverse effects after application of repeated, chroni...

...… Link: http://neuro.embs.org/files/2013/0656_FI.pdf ......... ............. FOLLOWING spinal cord injury (SCI), external urethral sphincter (EUS) spasms can prevent successful bladder emptying and result in medical complications. High Frequency Alternating Current in the kilohertz range (KHFAC) can be used to electrically block action potential...

...… Link: http://neuro.embs.org/files/2013/0655_FI.pdf ......... ..................... MANY neurological diseases and conditions are characterized by undesirable neural activity which can give rise to severe symptoms such as spasticity or chronic pain. A conduction block that is localized, fast acting and reversible is necessary to meet the needs...

GOALS: 1.Determine offset voltages resulting from off-the-shelf stimulators providing current-and voltage-controlled kHz waveforms. 2.Compare offset voltages on the stimulator output and electrode input side of DC-blocking capacitors. 3.Assess if large value inductors can prevent the development of DC-offset voltages by shunting direct currents. 4...

Kilohertz frequency alternating current (KHFAC) has been shown to produce a fast acting, reversible nerve block. The principal drawback to this technique is a short, but intense burst of firing at the initiation of the KHFAC which is referred to as the “onset response”. The “onset response” can be eliminated by the use of a second electrode which d...

The features and clinical applications of balanced-charge kilohertz frequency alternating currents (KHFAC) are reviewed. Preclinical studies of KHFAC block have demonstrated that it can produce an extremely rapid and reversible block of nerve conduction. Recent systematic analysis and experimentation utilizing KHFAC block have resulted in a signifi...

(EN)Devices and methods for blocking signal transmission through neural tissue. One step of a method includes placing a therapy delivery device into electrical communication with the neural tissue. The therapy delivery device includes an electrode contact having a high charge capacity material. A multi-phase direct current (DC) can be applied to th...

Functional Electrical Stimulation (FES) has widely been used to elicit neural activity to activate muscle for functional outcomes. But there are many diseases which result from undesirable neural activity which are equally debilitating. A localized, reversible, electrical nerve conduction block is an attractive way of addressing these conditions. H...

Neurotechnology has made major advances in development of interfaces to the nervous system that restore function in paralytic disorders. These advances enable both restoration of voluntary function and activation of paralyzed muscles to reanimate movement. The technologies used in each case are different, with external surface stimulation or percut...

The delivery of therapeutic levels of electrical current to neural tissue is a well-established treatment for numerous indications such as Parkinson's disease and chronic pain. While the neuromodulation medical device industry has experienced steady clinical growth over the last two decades, much of the core technology underlying implanted pulse ge...

Loss of arm and hand function is common after stroke. An implantable, 12-channel, electromyogram (EMG)-controlled functional electrical stimulation neuroprosthesis (NP) may be a viable assistive device for upper-limb hemiplegia. In this study, a research participant 4.8 yr poststroke underwent presurgical screening, surgical installation of the NP,...

Improved hand and arm function is the most sought after function for people living with a cervical spinal cord injury (SCI). Surgical techniques have been established to increase upper extremity function for tetraplegics, focusing on restoring elbow extension, wrist movement, and hand opening and closing. Additionally, more innovative treatments th...

Direct current, DC, can be used to quickly and reversibly block activity in excitable tissue, or to quickly and reversibly increase or decrease the natural excitability of a neuronal population. However, the practical use of DC to control neuronal activity has been extremely limited due to the rapid tissue damage caused by its use. We show that a s...

Neuroprostheses are devices that use electrical stimulation to activate paralyzed muscles in a coordinated manner to restore functional movements. These systems utilize a voluntarily-generated command signal for control of function. Current command signals include electromyographic (EMG) activity from muscles above the injury level that remain unde...