Burst Waveform Research Articles

Sacral Magnetic Neuromodulation with Intermittent Theta Burst Waveform Enhances Overactive Bladder: In Vivo Study

BackgroundThe current treatment options for overactive bladder (OAB) continue to pose challenges for refractory cases and may involve invasive procedures. To assess the potential benefit of non-invasive repetitive peripheral magnetic stimulation (rPMS) on sacral roots using intermittent theta burst stimulation (iTBS) as treatment option for OAB. The study involved a total of 33 rats, which were divided into three different experimental phases. Materials and methodsTo induce bladder overactivity rats were pretreated with a continuous transvesical infusion of 0.5% acetic acid (AA). During bladder infusion, the intravesical pressure was recorded using cystometrography (CMG) to investigate the effects of AA pretreatment and the therapeutic intervention of acute sacral rPMS using iTBS. ResultsPre-application of rPMS with iTBS at a 100% intensity significantly extended the mean first voiding time (Tv) in normal healthy rats to 132%. Acute rPMS iTBS at a 100% intensity resulted in a significant increase of the inter-contraction interval (ICI) to 121%. An AA model was established with continuous saline infusion after 0.5% AA treatment and resulted in significant reductions of Tv to 42% and ICI to 56% of the corresponding control values. Subsequently, rPMS iTBS at a 100% intensity on the sacral nerve effectively inhibited AA-induced bladder overactivity and significantly increased the ICI to 167%∼222%. No significant changes in maximum bladder pressure (Pmax) were found. ConclusionsSacral nerve rPMS with iTBS demonstrated the ability to suppress AA-induced bladder overactivity. This promising modality could be developed as an alternative approach to enhance bladder continence in OAB syndrome patients.

Determining hot-carrier transport dynamics from terahertz emission.

Understanding the ultrafast excitation and transport dynamics of plasmon-driven hot carriers is critical to the development of optoelectronics, photochemistry, and solar-energy harvesting. However, the ultrashort time and length scales associated with the behavior of these highly out-of-equilibrium carriers have impaired experimental verification of ab initio quantum theories. Here, we present an approach to studying plasmonic hot-carrier dynamics that analyzes the temporal waveform of coherent terahertz bursts radiated by photo-ejected hot carriers from designer nano-antennas with a broken symmetry. For ballistic carriers ejected from gold antennas, we find an ~11-femtosecond timescale composed of the plasmon lifetime and ballistic transport time. Polarization- and phase-sensitive detection of terahertz fields further grant direct access to their ballistic transport trajectory. Our approach opens explorations of ultrafast carrier dynamics in optically excited nanostructures.

Bursting with Potential: How Sensorimotor Beta Bursts Develop from Infancy to Adulthood.

Beta activity is thought to play a critical role in sensorimotor processes. However, little is known about how activity in this frequency band develops. Here, we investigated the developmental trajectory of sensorimotor beta activity from infancy to adulthood. We recorded EEG from 9-month-old, 12-month-old, and adult humans (male and female) while they observed and executed grasping movements. We analyzed "beta burst" activity using a novel method that combines time-frequency decomposition and principal component analysis. We then examined the changes in burst rate and waveform motifs along the selected principal components. Our results reveal systematic changes in beta activity during action execution across development. We found a decrease in beta burst rate during movement execution in all age groups, with the greatest decrease observed in adults. Additionally, we identified three principal components that defined waveform motifs that systematically changed throughout the trial. We found that bursts with waveform shapes closer to the median waveform were not rate-modulated, whereas those with waveform shapes further from the median were differentially rate-modulated. Interestingly, the decrease in the rate of certain burst motifs occurred earlier during movement and was more lateralized in adults than in infants, suggesting that the rate modulation of specific types of beta bursts becomes increasingly refined with age.SIGNIFICANCE STATEMENT We demonstrate that, like in adults, sensorimotor beta activity in infants during reaching and grasping movements occurs in bursts, not oscillations like thought traditionally. Furthermore, different beta waveform shapes were differentially modulated with age, including more lateralization in adults. Aberrant beta activity characterizes various developmental disorders and motor difficulties linked to early brain injury, so looking at burst waveform shape could provide more sensitivity for early identification and treatment of affected individuals before any behavioral symptoms emerge. More generally, comparison of beta burst activity in typical versus atypical motor development will also be instrumental in teasing apart the mechanistic functional roles of different types of beta bursts.

Diverse beta burst waveform motifs characterize movement-related cortical dynamics.

Classical analyses of induced, frequency-specific neural activity typically average band-limited power over trials. More recently, it has become widely appreciated that in individual trials, beta band activity occurs as transient bursts rather than amplitude-modulated oscillations. Most studies of beta bursts treat them as unitary, and having a stereotyped waveform. However, we show there is a wide diversity of burst shapes. Using a biophysical model of burst generation, we demonstrate that waveform variability is predicted by variability in the synaptic drives that generate beta bursts. We then use a novel, adaptive burst detection algorithm to identify bursts from human MEG sensor data recorded during a joystick-based reaching task, and apply principal component analysis to burst waveforms to define a set of dimensions, or motifs, that best explain waveform variance. Finally, we show that bursts with a particular range of waveform motifs, ones not fully accounted for by the biophysical model, differentially contribute to movement-related beta dynamics. Sensorimotor beta bursts are therefore not homogeneous events and likely reflect distinct computational processes.

ID: 214074 Sensing Evoked Responses Using Tonic and BurstDR Waveforms With Interleaving Strategy During Spinal Cord Stimulation

The efficacy of BurstDRTM (burst) waveform has been shown to be superior to tonic stimulation and it is widely used to relieve chronic pain. The characteristics of its complex waveform and the sub-paresthesia therapy makes burst waveform itself difficult to sense an evoked compound action potential (ECAP). Here, we propose a robust sensing strategy by interleaving tonic stimulation pulses in the therapeutic burst waveform to enable continuous sensing capabilities while delivering therapy with burst waveform.

ID: 222988 Treatment of Chronic Pain With a Battery-Free Spinal Cord Stimulation System: US nPower TM

A battery-free, spinal cord stimulation (SCS) system with a micro-implantable pulse generator (mIPG; Nalu Medical Inc., Carlsbad, CA) delivers various therapy options including tonic, novel pulsed stimulation pattern (PSP), current steering, burst waveforms, multi-area programs, layered programs, scheduled therapy and combination and paired therapies.

ID: 223288 Functional Outcomes From a Prospective Study With a Battery-Free Spinal Cord Stimulation System: US nPower

An ongoing, prospective, multi-center, post-market, open-label clinical study was initiated in the US to evaluate a battery-free SCS system (Nalu Medical Inc., Carlsbad, CA), with a micro implantable pulse generator (mIPG) in the treatment of intractable chronic pain in subjects with leg(s) and/or back pain. The system, with its ultra-long pulse width, delivers various therapy options including tonic, novel pulsed stimulation pattern, current steering, burst waveforms, multi-area programs, layered programs, scheduled therapy and combination and paired therapies.

ID: 212641 Salvage Therapy With Bilateral T12 and S1 DRG Stimulation for Post-Laminectomy Syndrome: A Case Report

Neuromodulation with tonic spinal cord stimulation (t-SCS) is well evidenced to manage chronic pain syndromes. However, for patients with post-laminectomy syndrome refractory to t-SCS, salvage therapies such as alternative waveforms of SCS (burst, high frequency, or multiple waveform) or dorsal root ganglion (DRG) stimulation have been studied. DRG stimulation is an emerging option for salvage therapy and was shown to be non-inferior and superior to t-SCS in treating lower extremity neuropathic pain for CRPS in the ACCURATE study. DRG stimulation’s use as salvage therapy for post-laminectomy syndrome is poorly reported. In this case, we present the treatment approach with DRG stimulation as salvage treatment for post-laminectomy syndrome refractory to t-SCS.

ID: 213578 Sensing Capability of BurstDR as a Sub-Paresthesia Therapeutic Waveform

The BurstDRTM waveform (burst) for spinal cord stimulation to relieve chronic pain demonstrated superior to classical tonic stimulation efficacy. Burst stimulation allows effective stimulation at sub-paresthesia level, improving patient’s experience. Regarding sensing and closed-loop approach, burst waveform raises a question if a spinal cord stimulation evoked compound action potential (ECAP) can be recorded and analyzed using this complicated waveform.

Characterization of high intensity progressive ultrasound beams in air at 300 kHz.

The majority of reported measurements on high intensity ultrasound beams in air are below 40 kHz and performed on standing waves inside of a guide. Here, experimental characterization of high intensity progressive and divergent sound beams in air at 300 kHz are presented. Measurements in this frequency range are challenging. Accurate characterization of high intensity sound beams requires a measurement bandwidth at least ten times the beam's primary frequency, as high intensity soundwaves steepen and form shocks and, therefore, contain significant signal power at harmonic frequencies. Hence, a measurement bandwidth of at least 3 MHz is required. Calibrated measurement microphones are generally not available in this frequency range. This limitation has been overcome by using a hydrophone with a calibrated response from 250 kHz to 20 MHz. A narrowband piezoelectric transducer is used as the source in this study, and it is capable of generating tone burst waveforms centered at 300 kHz with 160 dB sound pressure level surface pressure. Cumulative wave steepening and shock formation are observed in on-axis measurements. The source's surface vibration profile is measured using a scanning laser Doppler vibrometer, and the vibration profile is imported into a numerical wide-angle Khokhlov-Zabolotskaya-Kuznetsov simulation for comparison against measured on-axis waveforms.

PO116 / #1052 A PROSPECTIVE RANDOMIZED DOUBLE-BLINDED CROSSOVER TRIAL TO COMPARE CONVENTIONAL, BURST AND HIGH FREQUENCY SCS ON PAIN RELIEF IN PSPS-T2 PATIENTS: E-POSTER VIEWING

Studies have clearly demonstrated the efficacy of Spinal Cord Stimulation (SCS) to manage pain in Persistent Spinal Pain Syndrome after spinal surgery (PSPS-T2) patients (1,2). Tonic Conventional Stimulation (TCS) is the most used technique. However, studies showed that TCS does not appear to relieve pain for more than 30-55% of PSPS-T2 patients and provokes paresthesia that can be perceived as an uncomfortable sensation for the patients (3). To address these difficulties, new sub-paresthesia stimulation modalities were investigated such as BURST and High Frequency (HF) stimulation waveforms (4). Recent clinical trials reported evidence of their efficacy (5-12). Our study is the first randomized controlled trial to assess the efficacy of TCS, BURST and HF stimulation waveforms on pain relief.

Experimental characterization of high intensity progressive ultrasound beams in air

The majority of reported measurements on high intensity ultrasound beams in air are below 40 kHz and are performed on standing waves inside a guide. Here we present experimental characterization of high intensity progressive and divergent sound beams in air at 300 kHz. Measurements in this frequency range are challenging. Accurate characterization of high intensity sound beams requires a measurement bandwidth at least 10x the beam's primary frequency, as high intensity soundwaves steepen and form shocks, and therefore contain significant signal power at harmonic frequencies. A measurement bandwidth of at least 3 MHz is therefore required. Calibrated measurement microphones are generally not available in this frequency range. We have overcome this limitation by using a hydrophone with a calibrated response from 250 kHz—20 MHz. A narrowband piezoelectric transducer is used as the source in this study. The source is capable of generating tone burst waveforms centered at 300 kHz and with 160 dB SPL surface pressure. Cumulative wave steepening and shock formation are observed in on-axis measurements. The source's surface vibration profile is measured using a scanning LDV, and the vibration profile is imported into a numerical wide-angle KZK simulation for comparison against measured on-axis waveforms.

Identification of Shortwave Radio Communication Behavior Based on Autocorrelation Spectrogram Features

Cognitive communication behavior is becoming a research hotspot in the field of communication confrontation. In theory, the behavioral intention of noncooperating parties can be obtained by analyzing communication signals. Considering the complexity of the actual electromagnetic environment, even when the signal-to-noise ratio (SNR) is low, a certain accuracy still needs to be guaranteed. In this paper, according to five types of physical burst waveforms defined by the shortwave radio interoperability standard, a signal feature extraction method based on autocorrelation spectrogram features is proposed, and a two-input convolutional neural network (CNN) for classification is designed to improve the identification ability of shortwave communication behavior. The experimental results illustrate that the five kinds of shortwave radio communication behaviors can be accurately identified even when the noise is large. The research in this paper can directly analyze the communication behavior through physical layer signal without demodulation, which has the ability to grasp the communication behavior of the shortwave radio station in real time.

Study protocol: Effects of active versus passive recharge burst spinal cord stimulation on pain experience in persistent spinal pain syndrome type 2: a multicentre randomized trial (BURST-RAP study)

BackgroundSpinal cord stimulation (SCS) has shown to be an effective treatment for patients with persistent spinal pain syndrome type 2 (PSPS Type 2). The method used to deliver electrical charge in SCS is important. One such method is burst stimulation. Within burst stimulation, a recharge pattern is used to prevent buildup of charge in stimulated tissues. Two variations of burst waveforms are currently in use: one that employs active recharge and one that uses passive recharge. It has been suggested that differences exist between active and passive recharge paradigms related to both efficacy of pain relief and their underlying mechanism of action. Active recharge has been shown to activate both the medial spinal pathway, engaging cortical sensorimotor areas involved in location and intensity of pain, and lateral pathway, reaching brain areas involved with cognitive-emotional aspects of pain. Passive recharge has been suggested to act via modulation of thalamic neurons, which fire in a similar electrical pattern, and thereby modulate activity in various cortical areas including those related to motivational and emotional aspects of pain. The objective of this randomized clinical trial is to assess and compare the effect of active versus passive recharge Burst SCS on a wide spectrum of pain in PSPS Type 2 patients.MethodsThis multicentre randomized clinical trial will take place in 6 Dutch hospitals. PSPS Type 2 patients (n=94) will be randomized into a group receiving either active or passive recharge burst. Following a successful trial period, patients are permanently implanted. Patients complete the Pain Catastrophizing Scale (PCS) (primary outcome at 6 months), Numeric Pain Rating Scale (NRS), Patient Vigilance and Awareness Questionnaire (PVAQ), Hospital Anxiety and Depression Scale (HADS), Quality of Life (EQ-5D), Oswestery Disability Index (ODI), Patient Global Impression of Change (PGIC) and painDETECT questionnaires (secondary outcomes) at baseline, after trial, 1, 3, 6 and 12 months following implantation.DiscussionThe BURST-RAP trial protocol will shed light on possible clinical differences and effectivity of pain relief, including emotional-motivational aspects between active and passive burst SCS in PSPS Type 2 patients.Trial registrationClinicalTrials.gov registration: NCT05421273. Registered on 16 June 2022. Netherlands Trial Register NL9194. Registered on 23 January 2021.

Analgesic Effects of Tonic and Burst Dorsal Root Ganglion Stimulation in Rats With Painful Tibial Nerve Injury

ObjectivesDorsal root ganglion (DRG) stimulation is effective in treating chronic pain. While burst stimulation has been proven to enhance the therapeutic efficacy in spinal cord stimulation, currently only a tonic stimulation waveform is clinically used in DRG stimulation. We hypothesized that burst DRG stimulation might also produce analgesic effect in a preclinical neuropathic pain model. We evaluated both the therapeutic effects of burst DRG stimulation and the possible effects of DRG stimulation upon inflammation within the DRG in a preclinical neuropathic pain model. Materials and MethodsRats received either a painful tibial nerve injury or sham surgery. Analgesic effects of DRG stimulation were evaluated by testing a battery of evoked pain-related behaviors as well as measuring the positive affective state associated with relief of spontaneous pain using conditioned place preference. Histological evidence for neuronal trauma or neuroinflammation was evaluated. ResultsAll of the waveforms tested (20 Hz-tonic, 20 Hz-burst, and 40 Hz-burst) have similar analgesic effects in sensory tests and conditioned place preference. Long-term DRG stimulation for two weeks does not change DRG expression of markers for nerve injury and neuroinflammation. ConclusionsDRG stimulation using burst waveform might be also suitable for treating neuropathic pain.

Spinal Cord Stimulation as Treatment for Cancer and Chemotherapy-Induced Pain.

Neuropathic pain is a rampant disease exacting a significant toll on patients, providers, and health care systems around the globe. Neuromodulation has been successfully employed to treat many indications including failed back surgery syndrome (FBSS), complex regional pain syndrome (CRPS), phantom limb pain (PLP), radiculopathies, and intractable pelvic pain, among many others. Recent studies have also demonstrated efficacy for cancer-related pain and chemotherapy induced neuropathy with these techniques. Spinal cord stimulation (SCS) is the most commonly employed technique and involves implantation of percutaneous or paddle leads targeting the dorsal columns of the spinal cord with the goal of disrupting the pain signals traveling to the brain. Tonic, high frequency, and burst waveforms have all been shown to reduce pain and disability in chronic pain patients. Closed-loop SCS systems that automatically adjust stimulation parameters based on feedback (such as evoked compound action potentials) are becoming increasingly used to help ease the burden placed on patients to adjust their programming to their pain and position. Additionally, dorsal root ganglion stimulation (DRGS) is a newer technique that allows for dermatomal coverage especially in patients with pain in up to two dermatomes. Regardless of the technique chosen, neuromodulation has been shown to be cost-effective and efficacious and should be given full consideration in patients with chronic pain conditions.

ARTEMIS Observations of Plasma Waves in Laminar and Perturbed Interplanetary Shocks

Abstract The “Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun” mission provides a unique opportunity to study the structure of interplanetary shocks and the associated generation of plasma waves with frequencies between ∼50 and 8000 Hz due to its long duration electric and magnetic field burst waveform captures. We compare wave properties and occurrence rates at 11 quasi-perpendicular interplanetary shocks with burst data within 10 minutes (∼3200 proton gyroradii upstream, ∼1900 downstream) of the shock ramp. A perturbed shock is defined as possessing a large amplitude whistler precursor in the quasi-static magnetic field with an amplitude greater than 1/3 the difference between the upstream and downstream average magnetic field magnitudes; laminar shocks lack these large precursors and have a smooth, step function-like transition. In addition to wave modes previously observed, including ion acoustic, whistler, and electrostatic solitary waves, waves in the ion acoustic frequency range that show rapid temporal frequency change are common. Three shocks had burst captures in the ramp; of these, the two laminar shocks contained a wide range of large amplitude wave modes in the ramp whereas the one perturbed shock contained no such waves. Thus, energy dissipation through wave–particle interactions is more prominent in these two laminar shocks than in the perturbed shock. Based on observations from all 11 shocks, the wave occurrence rates for laminar shocks are higher in the transition region, especially the ramp, than downstream. In contrast, perturbed shocks have approximately 2–3 times the wave occurrence rate downstream than laminar shocks.

Effect of burst ratio on flow separation control using a dielectric barrier discharge plasma actuator at Reynolds number 2.6 × 105

In this study, the effect of the burst ratio (BR) on flow separation control using an alternating-current dielectric barrier discharge plasma actuator (DBDPA) was investigated. The effects of BR on the lift force on the NACA0015 airfoil were quantitatively evaluated by force measurements, and those on the flow field were measured by particle image velocimetry (PIV) and Schlieren visualisation. The force measurements showed that the recovery of the lift force decreased as BR increased, indicating that the flow separation control effect of the DBDPA decreased as BR increased. The PIV measurements showed that the temporal variation in vorticity was smaller at BR = 80% than at BR = 20% and that the vorticity did not change periodically at BR = 100%. Schlieren visualisation showed that DBDPA-induced flow produced a density gradient near the DBDPA electrode; the gradient was periodically observed and was found to be proportional to BR. In contrast, the density gradient in the separated shear layer varied at the end of each burst waveform, and the degree of variation decreased as BR increased. In addition, the root mean square value of the Schlieren signal intensity in the separated shear layer decreased with increasing BR. This result suggests that not only the strength and frequency of the disturbance input of the DBDPA but also the switching timing of the disturbance input are important for producing vorticity and thereby ensuring flow control.

Novel Intermittent Dosing Burst Paradigm in Spinal Cord Stimulation

IntroductionIntermittent dosing (ID), in which periods of stimulation‐on are alternated with periods of stimulation‐off, is generally employed using 30 sec ON and 90 sec OFF intervals with burst spinal cord stimulation (SCS). The goal of this study was to evaluate the feasibility of using extended stimulation‐off periods in patients with chronic intractable pain.Materials and MethodsThis prospective, multicenter, feasibility trial evaluated the clinical efficacy of the following ID stimulation‐off times: 90, 120, 150, and 360 sec with burst waveform parameters. After a successful trial (≥50% pain relief) using ID stimulation, subjects were titrated with OFF times beginning with 360 sec. Pain, quality of life, disability, and pain catastrophizing were evaluated at one, three, and six months after permanent implant.ResultsFifty subjects completed an SCS trial using ID stimulation settings of 30 sec ON and 90 sec OFF, with 38 (76%) receiving ≥50% pain relief. Pain scores were significantly reduced from baseline at all time points (p < 0.001). Improvements in quality of life, disability, and pain catastrophizing were aligned with pain relief outcomes; 45.8% of the subjects that completed the six‐month follow‐up visit used an OFF period of 360 seconds.ConclusionsID burst SCS effectively relieved pain for six months. The largest group of subjects used IDB settings of 30 sec ON and 360 sec OFF. These findings present intriguing implications for the optimal “dose” of electricity in SCS and may offer many advantages such as optimizing the therapeutic window, extending battery life, reducing recharge burden and, potentially, mitigating therapy habituation or tolerance.

Prospective Analysis Utilizing Intraoperative Neuromonitoring for the Evaluation of Inter-Burst Frequencies.

BackgroundIntraoperative neuromonitoring (IONM) for spinal cord stimulation (SCS) uses electromyography (EMG) responses to determine myotomal coverage as a marker for dermatomal coverage.ObjectiveThese responses can be utilized to evaluate the effects of stimulation platforms on the nervous system.MethodsEight patients were tested at inter-burst frequencies of 10 Hz, 20 Hz, 30 Hz, and 40 Hz using DeRidder Burst stimulation to determine the amplitude of onset of post-synaptic signal generation. Three patients had additional data recording amplitude of onset of tonic stimulation prior to and post DeRidder Burst stimulation at each inter-burst frequency. This represented post-synaptic excitability.ResultsIn all patients, the DeRidder Burst waveform generated EMG responses under all inter-burst frequencies including temporal summation, deeper fiber recruitment, and compounded action potentials. There was a non-significant decrease of 7.6–7.8% in amplitudes to generate response under 40 Hz, compared to the other frequencies. However, there was a 73.1% reduction in energy requirements at 10 Hz. The enhanced post-synaptic excitability effect was demonstrated at all frequencies.ConclusionDeRidder Burst has similar effects of temporal summation, deeper fiber recruitment, and compounded action potentials under IONM at 40 Hz, 30 Hz, 20 Hz, and 10 Hz. In addition, the hyperexcitability phenomenon was also observed regardless of the frequency. This demonstrates that postsynaptic responses captured via IONM may be a sensitive biomarker to SCS mechanism of action. In addition, lower inter-burst frequencies may have a similar clinical effect on pain relief thus reducing power consumption even further than current dosing paradigms.