Electrical Stimulation Techniques Research Articles

Beyond Painkillers: A Meta-Analysis of Non-Pharmacological Approaches for Managing Dysmenorrhea Symptoms

Dysmenorrhea, commonly known as painful menstruation, is a highly prevalent gynecological condition affecting millions of women globally. While pharmacological interventions offer temporary relief, they often come with undesirable side effects. Non-pharmacological approaches present a potentially safer and more sustainable alternative for managing dysmenorrhea symptoms. A comprehensive search of electronic databases, including PubMed, Scopus, and Web of Science, was conducted to identify randomized controlled trials (RCTs) published between 2014 and 2024 that investigated the effectiveness of non-pharmacological interventions for dysmenorrhea. The primary outcome was pain intensity reduction, while secondary outcomes included quality of life, absenteeism, and medication use. Data were pooled using a random-effects model, and standardized mean differences (SMDs) were calculated. Six RCTs met the inclusion criteria, encompassing a total of 600 participants. The non-pharmacological interventions evaluated included aerobic exercise, yoga, acupuncture, transcutaneous electrical nerve stimulation (TENS), heat therapy, and relaxation techniques. The pooled analysis revealed significant reductions in pain intensity across all interventions compared to control groups (SMD = -2.00, 95% CI: -2.39 to -1.61, p < 0.001). Aerobic exercise and yoga demonstrated the largest effect sizes (SMD = -2.5 and -2.5, respectively). Significant improvements were also observed in quality of life, absenteeism, and medication use. Non-pharmacological approaches, particularly aerobic exercise and yoga, are effective in managing dysmenorrhea symptoms. These findings strongly support the integration of non-pharmacological interventions into clinical practice as a first-line or adjunctive treatment option for dysmenorrhea.

A novel technique to identify and thermally ablate the greater occipital nerve for patients with occipital neuralgia: a retrospective study with cadaveric and ex-vivo validation.

This manuscript presents the challenges of treating various forms of headaches and the potential of interventional techniques targeting the greater occipital nerve (GON) to alleviate the burden on patients. Occipital neuralgia, characterized by stabbing or shooting pain in the base of the skull, is often associated with primary, cervicogenic, or migraine headaches. While occipital nerve blocks offer temporary relief, durable treatment options are limited. Pulsed radiofrequency (PRF) and thermal radiofrequency ablation (TRFA) have shown promise as minimally invasive procedures for long-term treatment. However, GON is not easily identified using ultrasound or fluoroscopic analysis; thereby, minimizing success of proper ablation. Here, the authors provide a percutaneous strategy to localize the GON and maximize lesion performance. We intend to provide an ex-vivo description of staggered bipolar radiofrequency (RF) lesioning and include the use of staggered bipolar lesioning of the GON and stimulation of the semispinalis capitis. We also analyzed the effectiveness and side effects from this ablation, retrospectively. Patients with chronic refractory GON neuralgia were selected for GON TRFA. A novel double needle technique of sequential electrical stimulation was used to localize the GON and approximate needle to nerve distance. Once the needles were positioned adjacent to the GON, TRFA was performed using a bipolar staggered technique. Twenty-two patients with GON were treated with TRFA using a novel double needle technique. Seventy-two percent of these patients reported greater than 50% pain relief at both 1 and 6 months following the procedure. The results of our ex-vivo study demonstrate that performing TRFA using the parallel needle bipolar approach separated 8 mm apart produced the most desirable lesion dimensions that may correlate with effective ablation of the GON. This study demonstrates a new localization and ablation technique to treat refractory headaches. However, larger studies are needed to confirm our findings.

Observing nociceptive detection thresholds and evoked potentials in diabetic patients with and without painful neuropathy

Aim: Diabetic polyneuropathy is the most described complication in patients with diabetes mellitus. A significant percentage of these patients experience disabling neuropathic pain (painful diabetic polyneuropathy). Small nerve fibers are primarily responsible for peripheral nociception, but objectively assessing its function is challenging. The primary objective of this study was to explore the task execution and outcomes of intra-epidermal electrical stimulation technique that combines nociceptive detection thresholds (NDT) and evoked potentials (EPs) in patients with diabetes. We compared the results of diabetic patients, both with and without painful diabetic polyneuropathy, with those of healthy controls to explore potential clinically relevant information. Methods: The NDT-EP method was applied to 38 patients with diabetes (18 with and 20 without chronic painful neuropathy) and 38 age- and sex-matched healthy controls. Individual mean NDTs, psychometric slopes, EP amplitudes, and the effect of the stimuli on EP amplitudes were analyzed and compared between groups using linear regression. Results: The findings revealed significantly lower detection rates, higher NDTs, and lower psychometric slopes in patients with painful diabetic polyneuropathy than in healthy controls. Both patient groups significantly exhibited lower mean EP amplitudes than healthy controls, which were not linked to pulse amplitudes but influenced by stimulus detection. Conclusions: This study showed altered NDT-EP outcomes in patients with painful diabetic polyneuropathy. Whereas the task execution, NDTs, and psychometric slopes may provide valuable insights into small fiber dysfunction, pulse amplitudes seemed not differently encoded in neurophysiological responses to intra-epidermal electrical stimulation near the detection threshold compared to controls. Future studies should investigate whether the altered NDT-EP outcomes could quantify small fiber dysfunction in patients with diabetes mellitus. We recommend further exploration of NDT-EP measures in other patient groups with nociceptive dysfunction.

Regulation of Cerebral Blood Flow Velocity by Transcutaneous Electrical Nerve Stimulation: A Preliminary Study

Objectives: An excessive and abrupt increase in cerebral blood flow may cause blood vessel damage, leading to stroke. Therefore, appropriate methods to immediately regulate blood flow velocity are important. Through an analysis of 31 healthy adults, we therefore investigated whether stimulating the common carotid artery (CCA) using transcutaneous electrical nerve stimulation (TENS) could modulate blood flow velocity in the CCA. Methods: Three stimulation intensities (below-threshold, threshold, and above-threshold) were applied in a random order. Blood velocity changes were examined by the measurement of peak systolic velocity (PSV) with Doppler ultrasound before, during, and after TENS stimulation. To evaluate arterial stiffness, pulse wave velocity (PWV) was calculated using CCA diameter, and blood pressure was measured before and after stimulation. Results: PSV changes in the below-threshold level were significant (p = 0.028). The PSV after below-threshold stimulation was significantly decreased by 2.23% compared to that before stimulation (p = 0.031). PWV showed no significant differences; however, a nonsignificant increase was observed immediately after stimulation only in the above-threshold condition. Above-threshold stimulation can increase vascular tone by activating the sympathetic nerve, possibly triggering vasoconstriction. Conclusions: A decrease in blood flow velocity may not be expected upon the above-threshold stimulation. In contrast, the below-threshold stimulation immediately reduces blood flow velocity, without significantly affecting hemodynamic function, such as arterial flexibility. Therefore, this short-term and low electrical stimulation technique can help to lower vascular resistance and prevent vascular damage from rapid blood flow velocity.

Pseudo-walking Sensation by Anteroposterior or Lateral Galvanic Vestibular Stimulation and Synchronous Foot-sole Vibrations.

The walking sensation is a result of the synthesis of multisensory inputs from various systems. The vestibular system, typically used for detecting acceleration, is a crucial component of the walking sensation. This study investigated the use of galvanic vestibular stimulation(GVS) to enhance the sensation of walking in virtual reality (VR) environments, particularly when users are seated and not engaged in active movements. GVS is a transcutaneous electric stimulation technique to evoke vestibular sensory responses and involves the application of a penetrating current to vestibular afferents. This study revealed that the pseudo-walking sensation can be intensified by applying lateral GVS. However, no difference was observed when it was synchronized with the walking rhythm represented by foot-sole vibration patterns. Furthermore, the study compares the effectiveness of lateral versus anterior-posterior GVS in enhancing walking sensations in VR. The findings provide novel perspectives on enhancing the VR walking experience through vestibular stimulation, even in scenarios in which the user is seated.

Investigating the Effects of Transcranial Alternating Current Stimulation on Cortical Oscillations and Network Dynamics.

Transcranial electrical brain stimulation techniques like transcranial direct current (tDCS) and transcranial alternating current (tACS) have emerged as potential tools for treating neurological diseases by modulating cortical excitability. These techniques deliver small electric currents to the brain non-invasively through electrodes on the scalp. tDCS uses constant direct current which weakly alters the membrane voltage of cortical neurons, while tACS utilizes alternating current to target and enhance cortical oscillations, though the underlying mechanisms are not fully understood more specifically. To elucidate how tACS perturbs endogenous network dynamics, we simulated spiking neuron network models. We identified distinct roles of the depolarizing and hyperpolarizing phases in driving network activity towards and away from the strong nonlinearity provided by pyramidal neurons. Exploring resonance effects, we found matching tACS frequency to the network's endogenous resonance frequency creates greater entrainment. Based on this, we developed an algorithm to determine the network's endogenous frequency, phase, and amplitude, then deliver optimized tACS to entrain network oscillations. Together, these computational results provide mechanistic insight into the effects of tACS on network dynamics and could inform future closed-loop tACS systems that dynamically tune stimulation parameters to ongoing brain activity.

Neuromodulation Treatments Targeting Pathological Synchrony for Tinnitus in Adults: A Systematic Review.

(1) Background: Tinnitus involves the conscious awareness of a tonal or composite noise for which there is no identifiable corresponding external acoustic source. For many people, tinnitus is a disorder associated with symptoms of emotional distress, cognitive dysfunction, autonomic arousal, behavioural changes, and functional disability. Many symptoms can be addressed effectively using education or cognitive behavioural therapy. However, there is no treatment that effectively reduces or alters tinnitus-related neurophysiological activity and thus the tinnitus percept. In this systematic review, we evaluated the effectiveness of neuromodulation therapies for tinnitus that explicitly target pathological synchronous neural activity. (2) Methods: Multiple databases were searched for randomised controlled trials of neuromodulation interventions for tinnitus in adults, with 24 trials included. The risk of bias was assessed, and where appropriate, meta-analyses were performed. (3) Results: Few trials used acoustic, vagal nerve, or transcranial alternating current stimulation, or bimodal stimulation techniques, with limited evidence of neuromodulation or clinical effectiveness. Multiple trials of transcranial direct current stimulation (tDCS) were identified, and a synthesis demonstrated a significant improvement in tinnitus symptom severity in favour of tDCS versus control, although heterogeneity was high. (4) Discussion: Neuromodulation for tinnitus is an emerging but promising field. Electrical stimulation techniques are particularly interesting, given recent advances in current flow modelling that can be applied to future studies.

Revealing detrimental effects of various DC electrical energy conditions on different multidrug resistant bacteria: a comprehensive study

The arbitrary discharge of contaminated wastes, especially that encompass multidrug resistant microbes (MDR), would broaden the circle of epidemic diseases such as COVID-19, which in turn deteriorate definitely the whole socioeconomics. Therefore, the employment of electrical stimulation techniques such as direct current (DC) with low energy considers being effective tool to impede spontaneous changes in microbial genetic makeup, which increases the prevalence of MDR phenomenon. Herein, the influence of different electric energies generated by DC electric field, volts and time on MDR-bacteria that are categorized among the highly ranked nosocomial pathogens, was scrutinized. Wherein, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis were examined as paradigms of Gram-negative and Gram-positive pathogens. The results declared the significant superior antagonizing potency of electric energy in a dose-dependent modality rather than the applied volts or exposure time. Notably, the exposure of bacterial cultures to140 J inhibited the bacterial count by > 78% and the range of 47–73% for Gram-negative and Gram-positive, respectively. While the suppression in their metabolic activity assessed by > 75% and 41–68%, respectively; reflecting the capability of electrical energy to induce viable but non-culturable (VBNC) state. Similarly, the results of total protein, extracellular protein content and lactate dehydrogenase activity emphasized the cell wall deterioration and losing of cell membrane integrity. Additionally, the elevating in ROS upon DC-exposure participated in DNA fragmentation and plasmid decomposability by the range of 33–60%. Further, SEM micrographs depicted drastic morphological deformations after electrical treatment. Strikingly, DC-treatment impaired antibiotic resistance of the examined strains against several antibiotics by > 64.2%. Generally, our comparative detailed study revealed deleterious potentiality of different DC-protocols in defeating microbial pollution, which could be invested as efficient disinfectant alternative in various sectors such as milk sterilization and wastewater purification.

Electrical stimulation in special clinical situations

Introduction: Neuromodulation is an approach used to treat diseases that are refractory to clinical treatments by employing electrical and chemical stimulation techniques, especially in cardiac, neurological, and psychiatric disorders. Objective: This study aims to provide an overview of the latest developments in neuromodulation therapies that use electrical stimulation. Methods and results: The present study describes the most common neuromodulation techniques. Neuroplasticity is used to adjust the ions and neural excitability in response to central and peripheral nervous system stimulation. The spinal cord, dorsal root, and gastric stimulations are effective treatments for neuropathies, chronic pain, muscle spasticity, epilepsy, depression, cluster headaches, heart failure, and gastroparesis symptoms. Deep brain stimulation and invasive cortical stimulation are medical procedures used selectively to treat Parkinson’s disease, dystonia, obsessive-compulsive disorder, and chronic pain. Barostimulation therapy is beneficial in controlling refractory hypertension, reducing the risk of cardiovascular events, and improving overall quality of life. Repetitive Transcranial Magnetic Stimulation is a recommended treatment option for fibromyalgia, neuropathic pain, chronic headaches, treatment-resistant depression, generalized anxiety disorders, schizophrenia, and attention deficit disorder. While controlling obesity shows promise in regulating appetite and promoting satiety, more research is needed to understand the safety and efficacy of these therapies in various groups. Conclusion: Neuromodulation devices hold promise for treating diseases that do not respond to clinical treatments. Additional clinical trials and studies are required to understand it fully.

Electrical stimulation for brighter persistent luminescence

An immature understanding of the mechanisms of persistent luminescence (PersL) has hindered the development of new persistent luminescent materials (PersLMs) with increased brightness. In this regard, in-situ direct current (DC) electric field measurements were conducted on a layered structure composed of the SrAl2O4:Eu2+,Dy3+ phosphor, and an electrode. In this study, the photoluminescence (PL) and afterglow properties were investigated with respect to voltage by analyzing the current signal and thermoluminescence (TL) spectroscopy. The intensity of PersL increased due to a novel phenomenon known as “external electric field stimulated enhancement of initial brightness of afterglow”. This dynamic process was illustrated via the use of a rate equation approach, where the electrons trapped by the ultra-shallow trap at 0.022 eV could be transferred through the conduction band during long afterglow. The afterglow intensity could reach 0.538 cd m−2 at a 6 V electric voltage. The design of an electric field stimulation technique enables the enhancement of the intensity of PersLMs and provides a new perspective for exploring the fundamental mechanics of certain established PersLMs.

Effects of transcutaneous auricular vagus nerve stimulation (tVNS) on balance in patient with chronic lower back pain

Background. tVNS is a technique of electrical stimulation of vagus nerve afferents that is used as a therapy for chronic pain. This study aims to analyze the effect of adding tVNS to exercise therapy on dynamic balance in chronic LBP patients measured by Maximized Reach Distance (%MAXD) and composite score of Modified Star Excursion Balance Test (MSEBT). Method. The method is an experimental study with a pretest-posttest randomized control group study. 22 people with mechanical chronic LBP aged 16-55 years who were randomly allocated into an exercise group (control group) and an exercise plus tVNS group (intervention group). MSEBT dynamic balance was measured before and after intervention. Results. In the intervention group the average MSEBT anterior right and left leg before (74.57±14.72;73.53±15.0) after (86.45±15.98; 86.98±15.9), posteromedial right and left before (88.23±16.76; 75.15±15.04) after (99.65±14.56, 92.19±11.91), right and left posterolateral before (76.66±13.89, 78.02±13.44) after (84.00±17.25, 84.30±13.90) there was a significant difference (p <0.05). Comparing anterior ΔMSEBT, right composite score and left posteromedial posterolateral ΔMSEBT between groups, there was a significant difference (p <0.05), not significant in right posteromedial posterolateral ΔMSEBT. Conclusion. The addition of tVNS to exercise therapy after 2 weeks on dynamic balance with MSEBT assessment showed a significant improvement in the intervention group. The results were better in the intervention group than in the control group. Further research is still needed to investigate the potential of adding tVNS to chronic LBP.

Transcranial electrical stimulation (TES) in patients with atopic dermatitis

BACKGROUND: Atopic dermatitis is the most common diseases in dermatology, among the main pathogenetic mechanisms of development of which a complex interaction of a genetically determined defect in the barrier function of the skin, an overactive state of the immune system is considered, and a neurogenic theory of disease development is not excluded, which is based on the relationship of anxiety-stress reactions and neuropsychiatric stresses with the occurrence of pathological changes on the skin. Modern atopic dermatitis therapy is characterized by the appointment of a large number of medications according to clinical recommendations, and the associated increase in allergic and toxic-allergic reactions dictates the need to search for new non-drug treatments for this disease. In order to prevent the pathological effects of stress, as well as to increase resistance to its damaging effects, activation of opioidergic mechanisms may be useful. AIM: To evaluate the effectiveness and acceptability of the transcranial electrical stimulation technique in patients with atopic dermatitis. MATERIALS AND METHODS: A controlled study was conducted among 60 patients with moderate atopic dermatitis, 33 women (55.0%) and 27 men (45.0%) aged 19 to 72 years. Transcranial electrical stimulation was carried out by a pulsed bipolar electrical stimulator with an acoustic effect "TRANSAIR-07", stimulation was carried out by an electric current with a frequency of 77.5 Hz and a duration of 3.5 ms. Patients underwent 10 procedures, 1 time a day, lasting 30 minutes, with a current of 1−3 mA. SCORAD, EASI, IGA, DLQI, HADS, and BDI scales were used to assess the dynamics of clinical manifestations. The assessment was carried out on the first and last day of treatment. RESULTS: During statistical data processing, when comparing the scales in the first and last days of the procedures, depending on the patient groups: the 1st group was the main one, received transcranial electrical stimulation treatment in combination with therapy, according to clinical recommendations, the 2nd group was the control group, received treatment according to clinical recommendations, without the use of transcranial electrical stimulation, significant improvement of itching indicators, clinical manifestations and improvement of quality of life after 4 weeks of therapy in both groups. A statistically more significant dynamics of the indicators of the main clinical scales in favor of combination therapy was established: according to the SCORAD scale ― in the main group from 47.50±2.25 to 21.00±1.00, in the control group from 47.00±2.00 to 39.00±1.75; DLQI ― in the main group from 8.00±2.00 to 2.00±0.75, in the control group ― from 8.50±1.50 to 5.00±1.00. CONCLUSION: The paper presents the positive results of our own research and presents data confirming the clinical effectiveness of transcranial electrostimulation in patients with atopic dermatitis compared with the traditional drug treatment of this disease, which allows us to recommend the treatment regimen we have proposed for widespread implementation in the practice of a dermatovenerologist.

Electrical Stimulation and Motor Function Rehabilitation in Spinal Cord Injury: A Systematic Review.

Spinal cord injury (SCI) often leads to devastating motor impairments, significantly affecting the quality of life of affected individuals. Over the last decades, spinal cord electrical stimulation seems to have encouraging effects on the motor recovery of impacted patients. This review aimed to identify clinical trials focused on motor function recovery through the application of epidural electrical stimulation, transcutaneous electrical stimulation, and functional electrical stimulation. Several clinical trials met these criteria, focusing on the impact of the aforementioned interventions on walking, standing, swimming, trunk stability, and upper extremity functionality, particularly grasp. After a thorough PubMed online database research, 37 clinical trials were included in this review, with a total of 192 patients. Many of them appeared to have an improvement in function, either clinically assessed or recorded through electromyography. This review outlines the various ways electrical stimulation techniques can aid in the motor recovery of SCI patients. It stresses the ongoing need for medical research to refine these techniques and ultimately enhance rehabilitation results in clinical settings.

Noninvasive intervention by transcranial ultrasound stimulation: Modulation of neural circuits and its clinical perspectives.

Low-intensity focused transcranial ultrasound stimulation (TUS) is an emerging noninvasive technique capable of stimulating both the cerebral cortex and deep brain structures with high spatial precision. This method is recognized for its potential to comprehensively perturb various brain regions, enabling the modulation of neural circuits, in a manner not achievable through conventional magnetic or electrical brain stimulation techniques. The underlying mechanisms of neuromodulation are based on a phenomenon where mechanical waves of ultrasound kinetically interact with neurons, specifically affecting neuronal membranes and mechanosensitive channels. This interaction induces alterations in the excitability of neurons within the stimulated region. In this review, we briefly present the fundamental principles of ultrasound physics and the physiological mechanisms of TUS neuromodulation. We explain the experimental apparatus and procedures for TUS in humans. Due to the focality, the integration of various methods, including magnetic resonance imaging and magnetic resonance-guided neuronavigation systems, is important to perform TUS experiments for precise targeting. We then review the current state of the literature on TUS neuromodulation, with a particular focus on human subjects, targeting both the cerebral cortex and deep subcortical structures. Finally, we outline future perspectives of TUS in clinical applications in psychiatric and neurological fields.

Effects of online tDCS and hf-tRNS on reading performance in children and adolescents with developmental dyslexia: a study protocol for a cross sectional, within-subject, randomized, double-blind, and sham-controlled trial.

Developmental Dyslexia (DD) is a brain-based developmental disorder causing severe reading difficulties. The extensive data on the neurobiology of DD have increased interest in brain-directed approaches, such as transcranial direct current stimulation (tDCS), which have been proposed for DD. While positive outcomes have been observed, results remain heterogeneous. Various methodological approaches have been employed to address this issue. However, no studies have compared the effects of different transcranial electrical stimulation techniques (e.g., tDCS and transcranial random noise stimulation, tRNS), on reading in children and adolescents with DD. The present within-subject, double-blind, and sham-controlled trial aims to investigate the effects of tDCS and hf-tRNS on reading in children and adolescents with DD. Participants will undergo three conditions with a one-week interval session: (A) single active tDCS session; (B) single active hf-tRNS session; and (C) single sham session (tDCS/hf-tRNS). Left anodal/right cathodal tDCS and bilateral tRNS will be applied over the temporo-parietal regions for 20 min each. Reading measures will be collected before and during each session. Safety and blinding parameters will be recordered. We hypothesize that tRNS will demonstrate comparable effectiveness to tDCS in improving reading compared to sham conditions. Additionally, we anticipate that hf-tRNS will exhibit a similar safety profile to tDCS. This study will contribute novel insights into the effectiveness of hf-tRNS, expediting the validation of brain-based treatments for DD.

Capacitive-Coupling-Responsive Hydrogel Scaffolds Offering Wireless In Situ Electrical Stimulation Promotes Nerve Regeneration.

Electrical stimulation (ES) has shown beneficial effects in repairing injured tissues. However, current ES techniques that use tissue-traversing leads and bulky external power suppliers have significant limitations in translational medicine. Hence, exploring noninvasive in vivo ES to provide controllable electrical cues in tissue engineering is an imminent necessity. Herein, a conductive hydrogel with in situ electrical generation capability as a biodegradable regeneration scaffold and wireless ES platform for spinal cord injury (SCI) repair is demonstrated. When a soft insulated metal plate is placed on top of the injury site as a wireless power transmitter, the conductive hydrogel implanted at the injury site can serve as a wireless power receiver, and the capacitive coupling between the receiver and transmitter can generate an alternating current in the hydrogel scaffold owing to electrostatic induction effect. In a complete transection model of SCI rats, the implanted conductive hydrogels with capacitive-coupling in situ ES enhance functional recovery and neural tissue repair by promoting remyelination, accelerating axon regeneration, and facilitating endogenous neural stem cell differentiation. This facile wireless-powered electroactive-hydrogel strategy thus offers on-demand in vivo ES with an adjustable timeline, duration, and strength and holds great promise in translational medicine.

Comparison between a Tail Clamp and Electrical Stimulation for Sevoflurane Minimum Anesthetic Concentration Determination in Green Iguanas (Iguana iguana).

This study aimed to compare the minimum anesthetic concentration (MAC) of sevoflurane in green iguanas using elec- trical stimulation and tail clamping as noxious stimuli. Seven adult green iguanas (Iguana iguana) weighing 580 to 1,300 g were enrolled. Each iguana was anesthetized twice after a 1-week washout period, with MAC being determined using a tail clamp (MACt) or electrical stimulation (MACe ) techniques. After sevoflurane mask induction and endotracheal intubation, the fraction of expired sevoflurane (Fe 'Sevo) was maintained at 3.1% for 15 min before noxious stimulation. In a bracketing design, the subsequent Fe'Sevo values were increased or decreased by 10% after positive or negative responses, respectively. Each targeted Fe 'Sevo was kept constant for 15 min before stimulation. In MACt, the noxious stimulus involved closing a Kelly hemostatic curved forceps to the first ratchet at the base of the tail. At the same site, in MACe, 2 30 × 0.8-mm hypodermic needles inserted 1 cm apart were connected to an electrical stimulator set to deliver 30 mA at 50 Hz at a 6.5-ms interval. The hemostat and the needles were repositioned 2 cm distally and on alternate tail sides at each stimulation round. Individual MAC was obtained when 2 consecutive crossover events occurred (a positive response preceding a negative response or vice versa), with the MAC of each group represented by the average of the individual MAC values. Median (interquartile range) values for the sevoflurane MAC did not differ significantly between groups (2.2 [2.2 to 2.8%] in MACe and 2.2 [1.8 to 3.5%] in MACt ; P = 0.812). Time to anesthesia induction, time to MAC measurement, heart rate (HR), end-tidal carbon dioxide (ET'CO2), and cloacal temperature were not different between groups. Both the tail-clamping and the electrical stimulation techniques yielded resembling sevoflurane MAC values in green iguanas, which makes the tail clamp a reliable alternative to electrical stimulation-based MAC research in this species.

Electric field temporal interference stimulation of neurons in vitro.

Electrical stimulation (ES) techniques, such as deep brain and transcranial electrical stimulation, have shown promise in alleviating the symptoms of depression and other neurological disorders in vivo. A new noninvasive ES method called temporal interference stimulation (TIS), possesses great potential as it can be used to steer the stimulation and possibly selectively modulate different brain regions. To study TIS in a controlled environment, we successfully established an in vitro 'TIS on a chip' setup using rat cortical neurons on microelectrode arrays (MEAs) in combination with a current stimulator. We validated the developed TIS system and demonstrated the spatial steerability of the stimulation by direct electric field measurements in the chip setup. We stimulated cultures of rat cortical neurons at 28 days in vitro (DIV) by two-channel stimulation delivering 1) TIS at 653 Hz and 643 Hz, resulting in a 10 Hz frequency envelope, 2) low-frequency stimulation (LFS) at 10 Hz and 3) high-frequency stimulation (HFS) at 653 Hz. Unstimulated cultures were used as control/sham. We observed the differences in the electric field strengths during TIS, HFS, and LFS. Moreover, HFS and LFS had the smallest effects on neuronal activity. Instead, TIS elicited neuronal electrophysiological responses, especially 24 hours after stimulation. Our 'TIS on a chip' approach eludicates the applicability of TIS as a method to modulate neuronal electrophysiological activity. The TIS on a chip approach provides spatially steerable stimuli while mitigating the effects of high stimulus fields near the stimulation electrodes. Thus, the approach opens new avenues for stimulation on a chip applications, allowing the study of neuronal responses to gain insights into the potential clinical applications of TIS in treating various brain disorders.

Novel Techniques for Musculoskeletal Pain Management after Orthopedic Surgical Procedures: A Systematic Review.

Effective postoperative pain management is critical for recovery after orthopedic surgery, but often remains inadequate despite multimodal analgesia. This systematic review synthesizes evidence on innovative modalities for enhancing pain control following major orthopedic procedures. Fifteen randomized controlled trials and comparative studies evaluating peripheral nerve blocks, local anesthetic infiltration, cryotherapy, transcutaneous electrical stimulation, adjunct medications, and other techniques are included. Thematic analysis reveals that peripheral nerve blocks and local anesthetic infiltration consistently demonstrate reduced pain scores, opioid consumption, and side effects versus conventional analgesia alone. Oral multimodal medications also show promise as part of opioid-sparing regimens. Adjunctive approaches like cryotherapy, music, and dexmedetomidine require further research to optimize protocols. Despite promising innovations, critical knowledge gaps persist regarding comparative effectiveness, optimal interventions and dosing, combination strategies, cost-effectiveness, and implementation. High-quality randomized controlled trials using standardized protocols are essential to guide the translation of enhanced multimodal regimens into clinical practice. This review provides a framework for pursuing research priorities and advancing evidence-based postoperative pain management across orthopedic surgeries.

Transsynaptic activation of human lumbar spinal motoneurons by transvertebral magnetic stimulation

Noninvasive spinal stimulation has been increasingly used in research on motor control and neurorehabilitation. Despite advances in percutaneous electrical stimulation techniques, magnetic stimulation is not as commonly used as electrical stimulation. Therefore, it is still under discussion what neuronal elements are activated by magnetic stimulation of the human spinal cord. In this study, we demonstrated that transvertebral magnetic stimulation (TVMS) induced transsynaptic activation of spinal motoneuron pools in the lumbar cord. In healthy humans, paired-pulse TVMS was given over an intervertebral space between the L1-L2 vertebrae with an interpulse interval of 100 ms, and the stimulus-evoked electromyographic (EMG) responses were recorded in the lower limb muscles. The results show that the evoked EMG responses after the 2nd pulse were clearly suppressed compared with the widespread responses evoked after the 1st pulse in the muscles of the lower extremity, indicating that the transsynaptic activation of spinal motoneurons by the 2nd pulse was suppressed by the effects produced by the 1st pulse. The inconsistent modulation of response suppression to stimulus intensity across individuals suggests that the TVMS-evoked EMG responses are composed of the compound potentials mediated by the direct activation of motor axons and the transsynaptic activation of motoneuron pools through sensory afferents and that the recruitment order of those fibers by TVMS may be nonhomogeneous across individuals.