Search

Purpose: To shorten 4D flow acquisitions by shortening TRs with fast RF pulses and gradient waveforms. Real‐time convex optimization is used to generate these gradients waveforms on the scanner. Theory and Methods: RF and slab‐select waveforms were shortened with a minimum phase SLR excitation and the time‐optimal variable‐rate selective excitation method. Real‐time convex optimization was used to shorten bipolar and spoiler gradients by finding the shortest gradient waveforms that satisfied constraints on scan parameters, gradient hardware, M0, M1, and peripheral nerve stimulation. Waveforms were calculated and TE and/or TR values were compared for a range of scan parameters and compared to a conventional 4D flow sequence. The method was tested in flow phantoms, and in the aorta and neurovasculature of volunteers (N = 10). Additionally, eddy current error was measured in a large phantom. Results: TEs and TRs were shortened by 21–32% and 20–34%, respectively, compared to the conventional sequence over a range of scan parameters. Bland‐Altman analysis of 2 flow phantom configurations showed flow rate bias of 0.3 mL/s and limits of agreement (LOA) of [−6.9, 7.5] mL/s for a cardiac phantom and a bias of −0.1 mL/s with LOA = [−0.4, 0.2] mL/s for a neuro phantom. Similar agreement was also seen for flow measurements in volunteers (bias = −1.0 and −0.1 mL/s, LOA = [−34.9, 33.0] and [−0.7, 0.6] mL/s). Measured eddy currents were 39% larger with the CVX + mpVERSE method. Conclusion: The real‐time optimized 4D flow gradients and fast slab‐selection excitation methods produced up to 34% faster TRs with excellent flow measurement agreement compared to a conventional 4D flow sequence. [ABSTRACT FROM AUTHOR]

Peripheral electrical stimulation (PES), which encompasses several techniques with heterogeneous physiological responses, has shown in some cases remarkable outcomes for pain treatment and clinical rehabilitation. However, results are still mixed, mainly because there is a lack of understanding regarding its neural mechanisms of action. In this study, we aimed to assess its effects by measuring cortical activation as indexed by functional near infrared spectroscopy (fNIRS). fNIRS is a functional optical imaging method to evaluate hemodynamic changes in oxygenated (HbO) and de-oxygenated (HbR) blood hemoglobin concentrations in cortical capillary networks that can be related to cortical activity. We hypothesized that non-painful PES of accessory spinal nerve (ASN) can promote cortical activation of sensorimotor cortex (SMC) and dorsolateral prefrontal cortex (DLPFC) pain processing cortical areas. Fifteen healthy volunteers received both active and sham ASN electrical stimulation in a crossover study. The hemodynamic cortical response to unilateral right ASN burst electrical stimulation with 10 Hz was measured by a 40-channel fNIRS system. The effect of ASN electrical stimulation over HbO concentration in cortical areas of interest (CAI) was observed through the activation of right-DLPFC (p = 0.025) and left-SMC (p = 0.042) in the active group but not in sham group. Regarding left-DLPFC (p = 0.610) and right-SMC (p = 0.174) there was no statistical difference between groups. As in non-invasive brain stimulation (NIBS) top-down modulation, bottom-up electrical stimulation to the ASN seems to activate the same critical cortical areas on pain pathways related to sensory-discriminative and affective-motivational pain dimensions. These results provide additional mechanistic evidence to develop and optimize the use of peripheral nerve electrical stimulation as a neuromodulatory tool (NCT 03295370— www.clinicaltrials.gov). [ABSTRACT FROM AUTHOR]

Unbearable chronic neuropathic pain, which can often not be resolved by conservative pain management techniques, calls for peripheral nerve stimulation. The technique, based on the Gate control hypothesis, uses low intensity current to block depolarization and conduction of neuronal membrane. Conditions such as intractable migraine, occipital and trigeminal neuralgia, burn injury pain, transformed migraine, among others, which cause intense pain can be treated by PNS, especially when the pain is localised and can be traced back to a specific nerve. Complication rates in PNS vary from 5% in some cases to 43% in others. Common complications include lead breakage, electrode migration, etc., meanwhile complications associated with every surgery like risks of anaesthesia, bleeding etc., are also present. PNS shows great potential in the treatment of intractable pain, and with its less invasiveness, high success rate, and development of advanced technologies like BION and SAINT, it is bound to become a standard procedure in the future for neuropathic pain management. [ABSTRACT FROM AUTHOR]

Background and Objectives: Chronic neuropathic pain is a common challenging condition following amputation. Recent research demonstrated the feasibility of percutaneously implanting fine-wire coiled peripheral nerve stimulation (PNS) leads in proximity to the sciatic and femoral nerves for postamputation pain. A multicenter, double-blinded, randomized, placebo-controlled study collected data on the safety and effectiveness of percutaneous PNS for chronic neuropathic pain following amputation.Methods: Twenty-eight lower extremity amputees with postamputation pain were enrolled. Subjects underwent ultrasound-guided implantation of percutaneous PNS leads and were randomized to receive PNS or placebo for 4 weeks. The placebo group then crossed over and all subjects received PNS for four additional weeks. The primary efficacy endpoint evaluated the proportion of subjects reporting ≥50% pain reduction during weeks 1-4.Results: A significantly greater proportion of subjects receiving PNS (n=7/12, 58%, p=0.037) demonstrated ≥50% reductions in average postamputation pain during weeks 1-4 compared with subjects receiving placebo (n=2/14, 14%). Two subjects were excluded from efficacy analysis due to eligibility changes. Significantly greater proportions of PNS subjects also reported ≥50% reductions in pain (n=8/12, 67%, p=0.014) and pain interference (n=8/10, 80%, p=0.003) after 8 weeks of therapy compared with subjects receiving placebo (pain: n=2/14, 14%; pain interference: n=2/13, 15%). Prospective follow-up is ongoing; four of five PNS subjects who have completed 12-month follow-up to date reported ≥50% pain relief.Conclusions: This work demonstrates that percutaneous PNS therapy may provide enduring clinically significant pain relief and improve disability in patients with chronic neuropathic postamputation pain.Trial Registration Number: NCT01996254. [ABSTRACT FROM AUTHOR]

Electrical stimulation of the cervical vagus nerve is an emerging treatment for inflammatory bowel disease (IBD). However, side effects from cervical vagal nerve stimulation (VNS) are often reported by patients. Here we hypothesized that stimulating the vagus nerve closer to the end organ will have fewer off-target effects and will effectively reduce intestinal inflammation. Specifically, we aimed to: (i) compare off-target effects during abdominal and cervical VNS; (ii) verify that VNS levels were suprathreshold; and (iii) determine whether abdominal VNS reduces chemically-induced intestinal inflammation in rats. An electrode array was developed in-house to stimulate and record vagal neural responses. In a non-recovery experiment, stimulation-induced off-target effects were measured by implanting the cervical and abdominal vagus nerves of anaesthetized rats (n = 5) and recording changes to heart rate, respiration and blood pressure during stimulation (10 Hz; symmetric biphasic current pulse; 320 nC per phase). In a chronic experiment, the efficacy of VNS treatment was assessed by implanting an electrode array onto the abdominal vagus nerve and recording in vivo electrically-evoked neural responses during the implantation period. After 14 days, the intestine was inflamed with TNBS (2.5% 2,4,6-trinitrobenzene sulphonic acid) and rats received therapeutic VNS (n = 7; 10 Hz; 320 nC per phase; 3 h/day) or no stimulation (n = 8) for 4.5 days. Stool quality, plasma C-reactive protein and histology of the inflamed intestine were assessed. Data show that abdominal VNS had no effect (two-way RM-ANOVA: P ≥ 0.05) on cardiac, respiratory and blood pressure parameters. However, during cervical VNS heart rate decreased by 31 ± 9 beats/minute (P ≥ 0.05), respiration was inhibited and blood pressure decreased. Data addressing efficacy of VNS treatment show that electrically-evoked neural response thresholds remained stable (one-way RM ANOVA: P ≥ 0.05) and therapeutic stimulation remained above threshold. Chronically stimulated rats, compared to unstimulated rats, had improved stool quality (two-way RM ANOVA: P < 0.0001), no blood in feces (P < 0.0001), reduced plasma C-reactive protein (two-way RM ANOVA: P < 0.05) and a reduction in resident inflammatory cell populations within the intestine (Kruskal–Wallis: P < 0.05). In conclusion, abdominal VNS did not evoke off-target effects, is an effective treatment of TNBS-induced inflammation, and may be an effective treatment of IBD in humans. [ABSTRACT FROM AUTHOR]

Purpose: Magnetic particle imaging (MPI) is a relatively new method to image the spatial distribution of magnetic nanoparticle (MNP) tracers administered to the body with high spatial and temporal resolution using an inhomogeneous magnetic field. The spatial information of the MNP's is encoded using a field free point (FFP), or a field free line (FFL), in which the magnetic field vanishes at a point, or on a line, respectively. FFL scanning has the advantage of improved sensitivity compared to FFP scanning as a result of higher signal‐to‐noise ratio. The trajectory traversed by the FFL or FFP is an important parameter of the MPI system and should be selected to achieve the best imaging quality in minimum scan time, while considering hardware constraints and patient safety. In this study, we analyzed the image quality of different FFL trajectories for a large field of view (FOV) using simulations, to provide a baseline information for FFL scanning MPI system design. Methods: We simulated a human‐sized FFL scanning MPI configuration to image a circular FOV with 160 mm diameter, and compared Radial, Spiral, Uniform Spiral, Flower, and Lissajous trajectories with different trajectory densities scanned by the FFL for constant scan time. We analyzed the system matrices of the trajectories in terms of mutual coherence and homogeneity of the spatial sensitivity. We calculated the maximum electric fields induced on a homogeneous conductive body by the selection field (SF) and the focus field (FF) to compare the trajectories based on the nerve stimulation threshold. The images were obtained using the system matrix reconstruction approach with two different image reconstruction methods. In the first one, we used the conventional image reconstruction method, algebraic reconstruction technique (ART), which gives a regularized least‐squares solution. In the second one, we used the state‐of‐the‐art alternating direction method of multipliers (ADMM), which minimizes a weighted sum of the l1‐norm and the total variation (TV) of the images. Results: The Radial and Spiral trajectories resulted in a poor imaging performance at low trajectory densities due to relatively high coherency and poor sensitivity of the measurements, respectively. For ART reconstruction, the highest image quality with the lowest trajectory density was achieved with the Uniform Spiral trajectory. Uniform Spiral, Flower, and Lissajous trajectories yielded comparable performance with ADMM reconstruction. The rotating SF induced higher electric field amplitude compared to the FF. Consequently, maximum allowable gradient at the same trajectory density was greater for the Radial trajectory compared to the other trajectories. Conclusions: For a large FOV coverage, the Uniform Spiral trajectory offers a good compromise between image quality and imaging time, taking safety and hardware limitations into account. The Radial trajectory, especially using l1‐norm and TV priors in the reconstruction, may be favorable in case the SF induced electric field is higher than that of the FF at the same frequency (e.g., relatively small FOV coverage). In general, ADMM reconstruction resulted in higher contrast and resolution compared to ART, leading to lighter requirements on the density of the trajectory. [ABSTRACT FROM AUTHOR]

Background: Post‐traumatic neuropathic pain in the head and face is a condition that is often refractory to medical management. Peripheral nerve stimulation (PNS) can be an effective treatment. Successful implantation of a novel minimally invasive wireless device is reported here. Objective: To assess analgesic effects of a minimally invasive wireless PNS device in the treatment of post‐traumatic supraorbital neuralgia (SON). Case Summary: The patient presented with SON following multiple post‐traumatic cranioplasty surgeries, which were complicated by infections. Medical and interventional management failed, and the patient reported a numeric rating scale (NRS) pain score of 8 out of 10. Two octopolar implantable neural stimulators (INSs) (StimRelieve LLC, Pompano Beach, FL, U.S.A.) were implanted with a minimally invasive, percutaneous technique to stimulate the supraorbital nerves. Stimulation parameters were set at a frequency of 10 kHz and a pulse width of 30 microseconds. Results: At 12‐ and 24‐month follow‐up evaluations, the patient's NRS score was only 2 out of 10, and the patient occasionally required 1 g of paracetamol to control the pain. Stimulation was reported to be paresthesia free. There were no adverse events related to the procedure or the treatment until today. Conclusions: High‐frequency stimulation with an external pulse generator and minimally invasive, percutaneous, and bilateral placement of 2 passive INSs on the supraorbital nerves resulted in a significant pain relief in this patient with post‐traumatic SON. The device was safe and effective, and the cosmesis was satisfactory. [ABSTRACT FROM AUTHOR]

The non-medical use of prescription drugs (NMUPD) among college students is escalating at an alarming rate. A limited number of studies have utilized a theoretical framework to influence this behavior. To utilize the reasoned-action approach theory to design and evaluate a web-based intervention to influence students' attitudes, perceived norms (PNs), perceived behavioral control (PBC) and intentions toward NMUPD. Using a two-group post-test only controlled trial, students were randomized to view either a general health website or a web-based intervention focused on NMUPD. The intervention was presented in multiple sections to address each component of the reasoned-action approach. Subsequently, respondents completed a web-survey. Independent t -tests were used to compare responses between the two groups. Of 391 respondents, 112 (28.9%) students indicated previous NMUPD. The intervention group had significantly (P = 0.04) more negative attitudes toward NMUPD. No significant differences were found in PNs (P = 0.11), PBC (P = 0.68) or intentions to NMUPD (P = 0.97). The intervention was successful in changing attitudes toward NMUPD. Targeting the intervention toward college students regardless of previous experiences of NMUPD might have led to insufficiency of the intervention to influence intentions. Additional research is needed to improve the intervention dissemination and utilization. [ABSTRACT FROM AUTHOR]

Post-amputation phantom limb pain (PLP) is a widespread phenomenon that can have physical, psychological, and functional impacts on amputees who experience the condition. The varying presentations and mechanisms of PLP make it difficult to effectively provide long-term pain relief. Multiple neuromodulatory approaches to treating PLP have focused on electrical stimulation of the peripheral nervous system, with varying degrees of success. More recently, research has been done to study the effects of neuroprosthetic approaches on PLP. Neuroprosthetics combine the use of a functional prosthetic with stimulation to the peripheral nerves in the residual limb. Although many of the neuroprosthetic studies focus on improving function, several have shown preliminary evidence for the reduction of severity of PLP. In this review we provide an overview of the current understanding of the neurological mechanisms that initiate and sustain PLP, as well as the neuromodulatory and neuroprosthetic approaches under development for treatment of the condition. Muscle Nerve 59:154-167, 2019. [ABSTRACT FROM AUTHOR]

Compression of the femoral nerve (FN) to the iliac fossa has been reported as a consequence of several pathologies as well as due to the aberrant muscles. The purpose of this research was to investigate the patterns of the accessory muscles of iliopsoas muscles and the relationship of the FN in fifty semi pelvis. Accessory muscular slips from iliacus and psoas, piercing or covering the FN, were found in 19 specimens (7.9%). Based on the macroscopic structure, the muscle was categorized into two types. Pattern 1 as the more frequent variation, was sheet muscular type covering the FN (17 specimens, 89.5%). Pattern 2, the less frequent variation was found on a muscular slip covering the FN (2 specimens, 10.5%). Iliac and psoas muscles and their variants on both types were defined. Appraising the relation between the muscle and the nerves, each disposition of the patterns may be a potential risk for nerve entrapment. The knowledge about the possible variations of the iliopsoas muscle complex and the FN may also give surgeons confidence during pelvic surgery. Recognition of these variations in normal anatomy may be useful to the clinicians when treating patients with refractory leg pain. [ABSTRACT FROM AUTHOR]

Purpose: As gradient performance increases, peripheral nerve stimulation (PNS) is becoming a significant constraint for fast MRI. Despite its impact, PNS is not directly included in the coil design process. Instead, the PNS characteristics of a gradient are assessed on healthy subjects after prototype construction. We attempt to develop a tool to inform coil design by predicting the PNS thresholds and activation locations in the human body using electromagnetic field simulations coupled to a neurodynamic model. We validate the approach by comparing simulated and experimentally determined thresholds for 3 gradient coils. Methods: We first compute the electric field induced by the switching fields within a detailed electromagnetic body model, which includes a detailed atlas of peripheral nerves. We then calculate potential changes along the nerves and evaluate their response using a neurodynamic model. Both a male and female body model are used to study 2 body gradients and 1 head gradient. Results: There was good agreement between the average simulated thresholds of the male and female models with the experimental average (normalized root‐mean‐square error: <10% and <5% in most cases). The simulation could also interrogate thresholds above those accessible by the experimental setup and allowed identification of the site of stimulation. Conclusions: Our simulation framework allows accurate prediction of gradient coil PNS thresholds and provides detailed information on location and "next nerve" thresholds that are not available experimentally. As such, we hope that PNS simulations can have a potential role in the design phase of high performance MRI gradient coils. [ABSTRACT FROM AUTHOR]

Hemiplegic shoulder pain (HSP) is a common comorbidity affecting stroke survivors. It can lead to chronic pain in a significant portion of patients. Prompt recognition and treatment may lead to improved outcomes, though it can be very challenging to treat. Peripheral nerve stimulation (PNS) has shown significant promise as a treatment modality for HSP. We present an interesting case of a patient with debilitating HSP that was unresponsive to a variety of medications and prior neuromodulation therapies. We report our experience utilizing the SPRINT PNS system and our outcomes treating a patient with refractory HSP. [ABSTRACT FROM AUTHOR]

Total knee arthroplasty (TKA) is one of the most commonly conducted surgeries in the United States. Typically, TKA is conducted to relieve pain from patients with long-standing osteoarthritis. Postoperative knee pain is a common issue after TKA. For some patients, postoperative knee pain exceeds the normal 3--6-month phase and becomes chronic. Pain is typically managed with the use of medications and physical therapy. In this case, we describe the use of peripheral nerve stimulation (PNS) of the saphenous and superior lateral genicular nerves for a patient experiencing chronic postoperative knee pain utilizing SPRINT PNS technology. [ABSTRACT FROM AUTHOR]

Objective Peripheral nerve stimulation provides targeted stimulation and pain relief within a specific nerve distribution. This technical case report provides a method to perform selective nerve root stimulation of thoracic and lumbar spinal nerves using ultrasonography. Methods Ultrasound-guided peripheral nerve stimulation of thoracic and lumbar spinal nerves allows better visualization of soft tissue anatomy and planning of needle trajectory. Conclusions Ultrasound-guided peripheral nerve stimulation procedures may provide a safer method for neurostimulation lead placement when compared with fluoroscopic-guided techniques. [ABSTRACT FROM AUTHOR]

Objective To present a history of the development of peripheral nerve stimulation. Methods Narrative literature review. Results Peripheral nerve stimulation has a history stretching from Scribonius Largus and eels in Mesopotamia to Michael Farady's discovery in London, the German-English physician Julius Althaus's application of electricity to a peripheral nerve, the sensational "Electreat" in the United States, to the application by Wall and Sweet of the gate theory proposed by Melzack and Wall to specialized neurosurgeons. Conclusions This is now a modern field in clinical neuroscience and medicine with improved technology, renewed interest by a diverse range of specialties, and accessibility with ultrasound. [ABSTRACT FROM AUTHOR]

Introduction Chronic knee pain is increasing in prevalence and is associated with substantial limitations in functional mobility. Peripheral nerve stimulation (PNS) has been increasingly used to treat various chronic pain conditions. However, there is a paucity of research exploring the potential therapeutic benefit of PNS for chronic knee pain. Methods This research is a retrospective case series of all patients who received PNS for the treatment of chronic knee pain performed at a single-center academic medical institution between March 2021 and June 2022. The primary outcome was percent pain reduction six months after implantation. Outcome data was obtained via chart review and phone calls to patients. Secondary outcomes included percent pain reduction two weeks and two months after implantation and adverse medical events related to the procedure and nerve stimulation. Results Fourteen individual patients received PNS for chronic knee pain during the study period. Three of these patients received bilateral PNS for a total of 17 cases. The mean percent pain reduction six months after implantation was 52% (SD=28.2) (N=12). A total of 75.0% of participants (9/12) reported  ≥ 50% reductions in pain six months after implantation. No adverse events were reported relating to the implantation procedure and/or nerve stimulation. Conclusion PNS is a safe and efficacious treatment modality for chronic knee pain with demonstrated long-term benefit. Further research should clarify patient factors associated with improved treatment response., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Kelly et al.)

Objectives: The primary aim of this review was to analyze the literature for the efficacy of neuromodulation interventions in treating both male and female sexual dysfunction., Materials and Methods: Studies were identified from PubMed, Scopus, PsychINFO, CINAHL, and Cochrane. Results were synthesized qualitatively without pooling owing to the heterogeneous nature of outcome assessments., Results: Overall findings from studies generally supported that neuromodulation interventions were associated with improvement in sexual function. Specific domains that improved in male patients included erectile function, desire, and satisfaction, whereas desire, arousal, orgasm, lubrication, quality of "sex life," intercourse capability, and dyspareunia improved in female patients. Male ejaculation, orgasm, and intercourse capability were the only domains that continued to decline after the use of neuromodulation interventions, although this was only reported in one study., Conclusion: Our review suggests that there may be promise and potential utility of neuromodulation in improving sexual dysfunction; however, further research is needed., (Copyright © 2022 International Neuromodulation Society. Published by Elsevier Inc. All rights reserved.)

Background: Neuromodulation has been successfully used globally to address severe refractory chronic pain for over five decades. Compared to the wide acceptance that it enjoys in United States and Europe, it is fairly underutilized in Asia, including India., Objectives: We conducted the first systematic nationwide survey to provide an overview of neuromodulation in the past 20 years to investigate the practice trends for severe refractory chronic pain and barriers for the uptake of neuromodulation therapies for pain in India., Design: A 20-point detailed questionnaire survey was sent out for online completion in August 2020 to practitioners in India involved in interventions for pain. The survey was completed by 112 practitioners (10% return rate). The response data collected were analyzed, tabulated, and presented as percentages., Results: The average duration of pain practice in India for the majority of respondents was less than a decade. About 70% of practitioners expressed that they manage severe refractory pain without neuromodulation. This survey confirms that neuromodulation is grossly underutilized for pain, comprising only 10% of total neuromodulation implants performed per annum in India. The most common indications were neuropathic pain (45%) and failed back surgery syndrome (42%). The respondents expressed the main barriers to be related to the cost (85%), lack of awareness (68%), and lack of good training (59%). More than 50% of respondents also expressed difficulty of access to neuromodulation therapies for pain and acceptance by patients., Conclusion: The younger generation of pain practitioners in India is becoming more aware and convinced about the role of neuromodulation to alleviate severe pain and suffering. An all-round approach combining improved training, awareness at various levels, more flexible options of newer technology and reimbursement approval can positively influence its use. This can be achieved with the collective efforts of physicians, insurers, industry, and focused academic activities of clinical societies., (Copyright © 2022 International Neuromodulation Society. Published by Elsevier Inc. All rights reserved.)

Objective: Chronic low back pain (CLBP) is multifactorial in nature, with recent research highlighting the role of multifidus dysfunction in a subset of nonspecific CLBP. This review aimed to provide a foundational reference that elucidates the pathophysiological cascade of multifidus dysfunction, how it contrasts with other CLBP etiologies and the role of restorative neurostimulation., Methods: A scoping review of the literature., Results: In total, 194 articles were included, and findings were presented to highlight emerging principles related to multifidus dysfunction and restorative neurostimulation. Multifidus dysfunction is diagnosed by a history of mechanical, axial, nociceptive CLBP and exam demonstrating functional lumbar instability, which differs from other structural etiologies. Diagnostic images may be used to grade multifidus atrophy and assess other structural pathologies. While various treatments exist for CLBP, restorative neurostimulation distinguishes itself from traditional neurostimulation in a way that treats a different etiology, targets a different anatomical site, and has a distinctive mechanism of action., Conclusions: Multifidus dysfunction has been proposed to result from loss of neuromuscular control, which may manifest clinically as muscle inhibition resulting in altered movement patterns. Over time, this cycle may result in potential atrophy, degeneration and CLBP. Restorative neurostimulation, a novel implantable neurostimulator system, stimulates the efferent lumbar medial branch nerve to elicit repetitive multifidus contractions. This intervention aims to interrupt the cycle of dysfunction and normalize multifidus activity incrementally, potentially restoring neuromuscular control. Restorative neurostimulation has been shown to reduce pain and disability in CLBP, improve quality of life and reduce health care expenditures., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Academy of Pain Medicine.)

The study evaluated the reliability and repeatability of the force and surface electromyography activity (EMG) outcomes obtained through voluntary and electrically evoked contractions of knee extensors in females ( n = 18) and males ( n = 20) and compared these data between sexes. Maximal isometric voluntary contractions (iMVCs) of knee extensors associated with electrical stimulation of the femoral nerve were performed over 4 days (48-h interval), with the first day involving familiarization procedures, the second involving three trials (1-h interval), and the third and fourth involving just one trial. The intraclass correlation coefficient (ICC), coefficient of variation (CV), and repeatability of outcomes from within- and between-day trials were determined for each sex. Females presented lower maximal voluntary force during iMVC (iMVC Force ) and associated vastus lateralis EMG activity (root mean square, RMS VL ), force evoked by potentiated doublet high-frequency (Db 100Force ) and single stimuli ( Q tw ), and M-wave amplitude than males ( P ≤ 0.01, partial eta squared ≥0.94). Voluntary activation (VA) and RMS VL /M-wave amplitude did not differ between sexes. iMVC Force , VA, Db 100Force , Q tw , and M-wave amplitude were the most reliable outcomes in within-day trials, with similar results between sexes (ICC > 0.62; CV < 6.4%; repeatability: 12.2%-22.6%). When investigating between-day trials, the iMVC Force , VA, Db 100Force , and Q tw were the most reliable (ICC > 0.66; CV < 7.5%; repeatability: 13.2%-33.45%) with similar results between sexes. In conclusion, females presented lower iMVC Force and evoked response than males. Although reliability and repeatability statistics vary between trials, data (e.g., from EMG or force signal), and sexes, most of the outcomes obtained through this technique are reliable in females and males. NEW & NOTEWORTHY Although reliability and repeatability of knee extensors vary according to the type of neuromuscular function outcome (e.g., from force or EMG responses), the trial intervals (i.e., hours or days), and the sex of the participant, most force and EMG outcomes obtained through these neuromuscular assessment protocols present ICC > 0.75, very good CV (<10%), and repeatability <25% in within- and between-day trials in both sexes.

Background: There is a large population of restless legs syndrome (RLS) patients who are refractory to medication. Whereas experts recommend off-label opioids as an effective long-term treatment for refractory RLS, reducing opioid dose could substantially reduce side effects and risks. Tonic motor activation (TOMAC) is a nonpharmacological therapeutic device indicated for refractory RLS. Here, we investigated if TOMAC could enable opioid dose reduction for refractory RLS., Methods: This prospective, open-label, single-arm clinical trial [NCT04698343] enrolled 20 adults taking ≤ 60 morphine milligram equivalents (MMEs) per day for refractory RLS. Participants self-administered 30-min TOMAC sessions bilaterally over the peroneal nerve when RLS symptoms presented. During TOMAC treatment, opioid dose was reduced iteratively every 2-3 weeks until Clinician Global Impression of Improvement (CGI-I) score relative to baseline exceeded 5. Primary endpoint was percent of participants who successfully reduced opioid dose ≥ 20% with CGI-I ≤ 5. Secondary endpoints included mean successful percent opioid dose reduction with CGI-I ≤ 5., Results: On average, participants were refractory to 3.2 medications (SD 1.6) and were taking a stable dose of opioids for 5.3 years (SD 3.9). Seventy percent of participants (70%, 14 of 20) successfully reduced opioid dose ≥ 20% with CGI-I ≤ 5. Mean percent opioid dose reduction with CGI-I ≤ 5 was 29.9% (SD 23.7%, n = 20) from 39.0 to 26.8 MME per day. Mean CGI-I score at the reduced dose was 4.0 (SD 1.4), indicating no change to RLS severity., Conclusions: For refractory RLS, TOMAC enabled substantial opioid dose reduction without increased RLS symptoms. These results suggest that TOMAC has the potential to reduce the risk profile associated with opioid therapy for refractory RLS., Trial Registration: ClinicalTrials.gov trial number NCT04698343 registered on January 6, 2021., (© 2023. The Author(s).)

Purpose of Review: Neurostimulation treatment options have become more commonly used for chronic pain conditions refractory to these options. In this review, we characterize current neurostimulation therapies for chronic pain conditions and provide an analysis of their effectiveness and clinical adoption. This manuscript will inform clinicians of treatment options for chronic pain., Recent Findings: Non-invasive neurostimulation includes transcranial direct current stimulation and repetitive transcranial magnetic stimulation, while more invasive options include spinal cord stimulation (SCS), peripheral nerve stimulation (PNS), dorsal root ganglion stimulation, motor cortex stimulation, and deep brain stimulation. Developments in transcranial direct current stimulation, repetitive transcranial magnetic stimulation, spinal cord stimulation, and peripheral nerve stimulation render these modalities most promising for the alleviating chronic pain. Neurostimulation for chronic pain involves non-invasive and invasive modalities with varying efficacy. Well-designed randomized controlled trials are required to delineate the outcomes of neurostimulatory modalities more precisely., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose of Review: Peripheral nerve stimulation (PNS) refers to the technique of utilizing electrical stimulation of peripheral nerves to inhibit the transmission of pain signals. PNS is used to treat chronic intractable pain and post-surgical or post-traumatic pain alongside a variety of other pain conditions, including headaches, facial pain, pelvic and urogenital pain, chest wall pain, residual limb or phantom limb pain, and back pain., Recent Findings: More recently, PNS has been used temporarily for periods of time less than 60 days to treat acute post-surgical pain. Peripheral nerve stimulation is believed to be effective due to its effects on both central and peripheral pathways. Centrally, it is proposed that the electrical pulses of PNS inhibit alpha-delta and C fibers, which decreases pain signaling in the higher centers of the central nervous system. Peripherally, gate theory is applied as it is theorized that PNS downregulates inflammatory mediators, endorphins, and neurotransmitters associated with pain signaling to decrease the transmission of efferent nociception and reduce pain sensations., Competing Interests: Compliance with Ethical Standards. Conflict of Interest: Authors do not have financial or non-financial interests that are directly or indirectly related to the work submitted for publication. Human and Animal Rights and Informed Consent: This article does not contain any studies with human or animal subjects performed by any of the authors., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Acupuncture is increasingly used to manage high blood pressure (BP) as a complementary therapy. However, the mechanisms underlying its hypotensive effects remain unclear. Our previous studies have shown that electroacupuncture (EA) at the ST36-37 acupoints, overlying the deep peroneal nerve, attenuates pressor responses through adenosine A 2A receptors (A 2A R) in the rostral ventrolateral medulla (rVLM). However, it is uncertain whether rVLM A 2A R contributes to EA's BP-lowering effect in sustained hypertension. We hypothesized that a course of EA treatment lowers BP, in part, through the activation of adenosine A 2A R in the rVLM in hypertensive rats. To mimic essential hypertension in the clinic, we performed EA in conscious Dahl salt-sensitive hypertensive rats (DSHRs). EA (0.1-0.4 mA, 2 Hz) was applied at ST36-37 for 30 min twice weekly for four weeks, while sham-EA was conducted in a similar manner but without electrical input. In hypertensive rats, BP was reduced by EA ( n  = 14) but neither by sham-EA ( n  = 14) nor in the absence of needling ( n  = 8). Following four weeks of eight treatments and then under anesthesia, EA's modulatory effect on elevated BP was reversed by unilateral rVLM microinjection of SCH 58261 (1 mM in 50 nl; an A 2A R antagonist; n  = 7; P  < 0.05) but not the vehicle ( n  = 5) in EA-treated DSHRs. Activation of rVLM A 2A R in DSHRs treated with sham-EA by an A 2A R agonist, CGS-21680 (0.4 mM in 50 nl; n  = 8), decreased BP. Unilateral administration of SCH 58261 or CGS-21680 into the rVLM did not alter basal BP in Dahl salt-sensitive rats fed a regular diet with normal BP. The A 2A R level in the rVLM after EA was increased compared to the sham-EA and untreated DSHRs ( n  = 5 in each group; all P  < 0.05). These data suggest that a 4-week twice weekly EA treatment reduced BP in salt-sensitive hypertensive rats likely through adenosine-mediated A 2A R in the rVLM., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (© 2023 Guo, Tjen-A-Looi, Nguyen, Fu, Su, Gong and Malik.)