Bioelectronics for electrical stimulation: materials, devices and biomedical applications

Bioelectronics is a hot research topic, yet an important tool, as it facilitates the creation of advanced medical devices that interact with biological systems to effectively diagnose, monitor and treat a broad spectrum of health conditions. Electrical stimulation (ES) is a pivotal technique in bioelectronics, offering a precise, non-pharmacological means to modulate and control biological processes across molecular, cellular, tissue, and organ levels. This method holds the potential to restore or enhance physiological functions compromised by diseases or injuries by integrating sophisticated electrical signals, device interfaces, and designs tailored to specific biological mechanisms. This review explains the mechanisms by which ES influences cellular behaviors, introduces the essential stimulation principles, discusses the performance requirements for optimal ES systems, and highlights the representative applications. From this review, we can realize the potential of ES based bioelectronics in therapy, regenerative medicine and rehabilitation engineering technologies, ranging from tissue engineering to neurological technologies, and the modulation of cardiovascular and cognitive functions. This review underscores the versatility of ES in various biomedical contexts and emphasizes the need to adapt to complex biological and clinical landscapes it addresses.

Transcutaneous electrical nerve stimulation and catheter-related bladder discomfort following transurethral resection of bladder tumour: A randomised controlled trial

BACKGROUND

Catheter-related bladder discomfort (CRBD) is problematic in patients with a urinary catheter. Transcutaneous electrical nerve stimulation (TENS) is a non-invasive analgesic modality used to relieve various types of pain.

OBJECTIVES

We evaluated the effect of TENS on CRBD after transurethral resection of bladder tumours (TURBT).

DESIGN

A randomised controlled trial.

SETTING

A large university tertiary hospital, from October 2022 to March 2023.

PATIENTS

Patients requiring urinary catheterisation after TURBT.

INTERVENTION

In this randomised controlled trial, patients were randomly allocated to the TENS (n  = 56) or control (n  = 56) groups. CRBD manifests as a burning sensation with an urge to void or discomfort in the suprapubic area. Moderate to severe CRBD was defined as patients self-reporting CRBD symptoms with or without behavioural response, including attempts to remove the urinary catheter, intense verbal reactions, and flailing limbs. TENS was performed from the end of surgery to 1 h postoperatively.

MAIN OUTCOME MEASURE

The primary endpoint was considered moderate to severe CRBD immediately postoperatively. Secondary endpoints included moderate to severe CRBD at 1, 2 and 6 h postoperatively. Additionally, postoperative pain, patient satisfaction, and TENS-related adverse effects were evaluated.

RESULTS

Moderate to severe CRBD immediately postoperatively was significantly less frequent in the TENS group than in the control group: 10 (17.9%) vs. 34 (60.7%); P < 0.001; relative risk (95% CI) = 0.294 (0.161 to 0.536); absolute risk reduction = 0.43; number needed to treat = 2.3. Moderate to severe CRBD differed between the two groups at 1 h postoperatively: 1 (1.8%) vs. 16 (28.6%); P < 0.001; relative risk = 0.06 (95% CI 0.01 to 0.46); absolute risk reduction = 0.27; number needed to treat = 3.7. The TENS group exhibited a significantly lower score for postoperative pain at 1 h (1.8 ± 0.6 vs. 2.2 ± 0.4; P < 0.001, mean difference (95% CI) = 0.4 (0.2 to 0.6) and a higher score for patient satisfaction, 5.0 (4.0 to 6.0) vs. 3.0 (3.0 to 4.0); P < 0.001; median difference (95% CI) = 2.0 (1.0 to 2.0).

CONCLUSIONS

TENS reduced moderate to severe CRBD, decreased postoperative pain, and increased patient satisfaction after TURBT.

CLINICAL TRIAL REGISTRY

Clinical Research Information Service (KCT0007450).

VISUAL ABSTRACT

http://links.lww.com/EJA/B12.

Surgical Pearls for Safe and Precise Decision-Making during Modified Selective Neurectomy Surgery

In this short communication: (1) A transcutaneous electrical nerve stimulaton stimulator is a cost-effective solution for the predictable stimulation of mimicry and for precise decision-making. (2) Positioning a simple shatterproof mirror in front of an operated facial half enables the primary surgeon to simultaneously see and stimulate at the operative site and to scrutinize the mimicry for decision-making. (3) A misconception in the literature regarding colors used for tagging "branches for transection" and "branches for preservation" is clarified, and a third tag-color is suggested for times of ambiguity. (4) The principle of distal execution of the surgery and technical considerations are underlined for maximal transection and maximal preservation. The modified selective neurectomy surgery is the current golden standard of post facial paralysis synkinesis treatment, and developing a learning curve in this type of surgery is like walking a tightrope, where the surgeon must keep pushing the limits with precise decision-making and a small margin of error. It is important to be reminded that the first aim is primum non nocere, and the second aim is to improve the condition of patients as much as possible. The above-mentioned principles and solutions increase precision and safety, assisting surgeons to achieve better outcomes.

Relationships between nitric oxide biomarkers and physiological outcomes following dietary nitrate supplementation

Dietary nitrate (NO3-) supplementation can increase nitric oxide (NO) bioavailability, reduce blood pressure (BP) and improve muscle contractile function in humans. Plasma nitrite concentration (plasma [NO2-]) is the most oft-used biomarker of NO bioavailability. However, it is unclear which of several NO biomarkers (NO3-, NO2-, S-nitrosothiols (RSNOs)) in plasma, whole blood (WB), red blood cells (RBC) and skeletal muscle correlate with the physiological effects of acute and chronic dietary NO3- supplementation. Using a randomized, double-blind, crossover design, 12 participants (9 males) consumed NO3--rich beetroot juice (BR) (∼12.8 mmol NO3-) and NO3--depleted placebo beetroot juice (PL) acutely and then chronically (for two weeks). Biological samples were collected, resting BP was assessed, and 10 maximal voluntary isometric contractions of the knee extensors were performed at 2.5-3.5 h following supplement ingestion on day 1 and day 14. Diastolic BP was significantly lower in BR (-2 ± 3 mmHg, P = 0.03) compared to PL following acute supplementation, while the absolute rate of torque development (RTD) was significantly greater in BR at 0-30 ms (39 ± 57 N m s-1, P = 0.03) and 0-50 ms (79 ± 99 N m s-1, P = 0.02) compared to PL following two weeks supplementation. Greater WB [RSNOs] rather than plasma [NO2-] was correlated with lower diastolic BP (r = -0.68, P = 0.02) in BR compared to PL following acute supplementation, while greater skeletal muscle [NO3-] was correlated with greater RTD at 0-30 ms (r = 0.64, P=0.03) in BR compared to PL following chronic supplementation. We conclude that [RSNOs] in blood, and [NO3-] in skeletal muscle, are relevant biomarkers of NO bioavailability which are related to the reduction of BP and the enhanced muscle contractile function following dietary NO3- ingestion in humans.

Obstructive sleep apnea improves with non-invasive hypoglossal nerve stimulation using temporal interference

BACKGROUND

Peripheral nerve stimulation is used in both clinical and fundamental research for therapy and exploration. At present, non-invasive peripheral nerve stimulation still lacks the penetration depth to reach deep nerve targets and the stimulation focality to offer selectivity. It is therefore rarely employed as the primary selected nerve stimulation method. We have previously demonstrated that a new stimulation technique, temporal interference stimulation, can overcome depth and focality issues.

METHODS

Here, we implement a novel form of temporal interference, bilateral temporal interference stimulation, for bilateral hypoglossal nerve stimulation in rodents and humans. Pairs of electrodes are placed alongside both hypoglossal nerves to stimulate them synchronously and thus decrease the stimulation amplitude required to activate hypoglossal-nerve-controlled tongue movement.

RESULTS

Comparing bilateral temporal interference stimulation with unilateral temporal interference stimulation, we show that it can elicit the same behavioral and electrophysiological responses at a reduced stimulation amplitude. Traditional transcutaneous stimulation evokes no response with equivalent amplitudes of stimulation.

CONCLUSIONS

During first-in-man studies, temporal interference stimulation was found to be well-tolerated, and to clinically reduce apnea-hypopnea events in a subgroup of female patients with obstructive sleep apnea. These results suggest a high clinical potential for the use of temporal interference in the treatment of obstructive sleep apnea and other diseases as a safe, effective, and patient-friendly approach.

TRIAL REGISTRATION

The protocol was conducted with the agreement of the International Conference on Harmonisation Good Clinical Practice (ICH GCP), applicable United States Code of Federal Regulations (CFR) and followed the approved BRANY IRB File # 22-02-636-1279.

Pulsed Electromagnetic Fields (PEMF)-Physiological Response and Its Potential in Trauma Treatment

Environmental biophysical interactions are recognized to play an essential part in the human biological processes associated with trauma recovery. Many studies over several decades have furthered our understanding of the effects that Pulsed Electromagnetic Fields (PEMF) have on the human body, as well as on cellular and biophysical systems. These investigations have been driven by the observed positive clinical effects of this non-invasive treatment on patients, mainly in orthopedics. Unfortunately, the diversity of the various study setups, with regard to physical parameters, molecular and cellular response, and clinical outcomes, has made it difficult to interpret and evaluate commonalities, which could, in turn, lead to finding an underlying mechanistic understanding of this treatment modality. In this review, we give a birds-eye view of the vast landscape of studies that have been published on PEMF, presenting the reader with a scaffolded summary of relevant literature starting from categorical literature reviews down to individual studies for future research studies and clinical use. We also highlight discrepancies within the many diverse study setups to find common reporting parameters that can lead to a better universal understanding of PEMF effects.

A review of current rehabilitation practices and their benefits in patients with multiple sclerosis

Multiple sclerosis (MS) is a chronic, debilitating disease characterised by demyelination of the nerves of the central nervous system that results in patients progressively losing the ability to perform daily tasks. As there is no cure for this disease, rehabilitation therapy is an important aspect of care; assisting patients to regain or retain function and improve their physical, mental and social wellbeing. At present there is no current consistent model of care for MS, likely due to the variable symptom presentation. Various forms of rehabilitation therapy are available, and these include physical rehabilitation methods, such as balance and gait therapy, speech and respiration rehabilitation, and occupational therapy. Contrary to previous understanding, exercise-based therapies have shown various benefits for patients with MS, and in addition to improving MS-related physical symptoms, have been shown to reduce the risk of developing cardiovascular disease and can improve cognitive function. Cognition rehabilitation therapy specifically focuses on behavioural tasks and is divided into two main forms: compensatory rehabilitation, which offers cognitive functioning benefits, and restorative rehabilitation, which offers memory benefits. Excitation therapies include cranial stimulation and other stimulation rehabilitation methods such as focal muscle vibration therapy and these non-invasive techniques may improve patient's physical ability. Additionally, more novel rehabilitation methods include robot-assisted gait therapy and telerehabilitation, both of which are expected to play progressively more prominent roles in the future of rehabilitation therapy. The structure of the care team has been found to impact patient outcomes, and both in- and out-patient care settings have been found to be beneficial, dependant on the patient's circumstances, with certain patients better suited to a particular setting. While a single point of care is recommended for patients, a multidisciplinary care team and regular reassessment is recommended to manage changing symptoms and ensure continuity of care. The importance of the critical components of rehabilitation have been identified, and these are of vital importance in achieving beneficial outcomes. These components include the patients' participation in the treatment, goal setting with a multidisciplinary care team, a guiding-light purpose for the patient, which focusses on recognizing their personal potential and obtaining improvements through a tailored plan. The final critical component of rehabilitation is the results measurement, which highlights the need for a quantifiable reduction in impairment and improvement in activity and participation. Overall, a lack of standardisation in outcome measurements makes comparison challenging. This is particularly important when comparing standard methods of care with more novel rehabilitation techniques. However, within the broad area of rehabilitation therapies, it is clear that patients with MS can benefit from rehabilitation practices; physically, mentally and socially.

Physiotherapeutic Strategies and Their Current Evidence for Canine Osteoarthritis

Osteoarthritis (OA) is a common and debilitating condition in domestic dogs. Alongside pharmaceutical interventions and weight loss, exercise and physiotherapy (PT) are important measures in maintaining patient mobility and quality of life. Physiotherapy for OA aims to reduce pain, optimize muscular function and maintain joint function. Physiotherapeutic plans typically include PT exercises combined with therapeutic modalities, lifestyle and environmental modifications to improve the patient's overall quality of life and function. Information on therapeutic clinical efficacy of physiotherapeutic measures for canine OA is still very limited. Thus, physiotherapeutic strategies are still primarily based on evidence extrapolated from human protocols tailored to people with OA. The authors propose a simple systematic PT approach for canine OA, prioritizing measures according to simplicity, cost effectiveness and practicality. This guide (the "Physiotherapy Pyramid") aims to provide a clear stratified approach to simplify decision making and planning for owners, veterinarians and veterinary physiotherapists, leading to more straightforward design and implementation of treatment plans. Measures are implemented starting at the base of the pyramid, subsequently progressing to the top, allowing effective and practical interventions to be prioritized. The levels of the pyramid are in ascending order: environmental modification, exercise plan, OA-specific home exercises and treatment by a veterinary physiotherapist.

A bioresorbable peripheral nerve stimulator for electronic pain block

Local electrical stimulation of peripheral nerves can block the propagation of action potentials, as an attractive alternative to pharmacological agents for the treatment of acute pain. Traditional hardware for such purposes, however, involves interfaces that can damage nerve tissue and, when used for temporary pain relief, that impose costs and risks due to requirements for surgical extraction after a period of need. Here, we introduce a bioresorbable nerve stimulator that enables electrical nerve block and associated pain mitigation without these drawbacks. This platform combines a collection of bioresorbable materials in architectures that support stable blocking with minimal adverse mechanical, electrical, or biochemical effects. Optimized designs ensure that the device disappears harmlessly in the body after a desired period of use. Studies in live animal models illustrate capabilities for complete nerve block and other key features of the technology. In certain clinically relevant scenarios, such approaches may reduce or eliminate the need for use of highly addictive drugs such as opioids.

Touch, Texture and Haptic Feedback: A Review on How We Feel the World around Us

Touch is one most of the important aspects of human life. Nearly all interactions, when broken down, involve touch in one form or another. Recent advances in technology, particularly in the field of virtual reality, have led to increasing interest in the research of haptics. However, accurately capturing touch is still one of most difficult engineering challenges currently being faced. Recent advances in technology such as those found in microcontrollers which allow the creation of smaller sensors and feedback devices may provide the solution. Beyond capturing and measuring touch, replicating touch is also another unique challenge due to the complexity and sensitivity of the human skin. The development of flexible, soft-wearable devices, however, has allowed for the creating of feedback systems that conform to the human form factor with minimal loss of accuracy, thus presenting possible solutions and opportunities. Thus, in this review, the researchers aim to showcase the technologies currently being used in haptic feedback, and their strengths and limitations.

A Comprehensive Strategy to Pain Management for Cancer Patients in an Inpatient Rehabilitation Facility

Cancer pain has been shown to have a significant negative impact on health-related quality of life (HRQoL) for people experiencing it. This is also true for patients admitted to inpatient rehabilitation facilities (IRFs). An interdisciplinary approach is often needed to fully address a person's pain to help them attain maximum functional independence and to ensure a safe discharge home. Improving a patient's performance status in an IRF may also be a crucial determinant in their ability to continue receiving treatment for their cancer. However, if a person is determined to no longer be a candidate for aggressive, disease modulating treatment, IRFs can also be utilized to help patients and family's transition to comfort directed care with palliative or hospice services. This article will discuss the interventions of the multidisciplinary inpatient rehabilitation team to address a person's pain.

Effect of Modulated TENS on Corticospinal Excitability in Healthy Subjects

Conventional transcutaneous electrical nerve stimulation (TENS) has been reported to effectively alleviate chronic pain, including phantom limb pain (PLP). Recently, literature has focused on modulated TENS patterns, such as pulse width modulation (PWM) and burst modulation (BM), as alternatives to conventional, non-modulated (NM) sensory neurostimulation to increase the efficiency of rehabilitation. However, there is still limited knowledge of how these modulated TENS patterns affect corticospinal (CS) and motor cortex activity. Therefore, our aim was to first investigate the effect of modulated TENS patterns on CS activity and corticomotor map in healthy subjects. Motor evoked potentials (MEP) elicited by transcranial magnetic stimulation (TMS) were recorded from three muscles before and after the application of TENS interventions. Four different TENS patterns (PWM, BM, NM 40 Hz, and NM 100 Hz) were applied. The results revealed significant facilitation of CS excitability following the PWM intervention. We also found an increase in the volume of the motor cortical map following the application of the PWM and NM (40 Hz). Although PLP alleviation has been reported to be associated with an enhancement of corticospinal excitability, the efficiency of the PWM intervention to induce pain alleviation should be validated in a future clinical study in amputees with PLP.

Effect of Neural Mobilization Exercises in Patients With Low Back-Related Leg Pain With Peripheral Nerve Sensitization: A Prospective, Controlled Trial

Objective

The aim of this study was to investigate the short-term effect of slider and tensioner exercises on pain and range of motion (ROM) of straight leg raise (SLR) and slump tests in patients with low back-related leg pain with peripheral nerve sensitization.

Methods

In this prospective, controlled trial, 51 patients with low back-related leg pain with peripheral nerve sensitization were divided into 3 treatment groups: slider (slider neural mobilization exercise + transcutaneous electric nerve stimulation [TENS]), tensioner (tensioner neural mobilization exercise + TENS), and control (only TENS). Each patient received 6 sessions over 2 weeks. The following outcomes were measured at baseline and after the first, third, and sixth sessions: visual analog scale (VAS) for pain and ROM of SLR and slump tests were performed for the symptomatic side.

Results

Compared with controls, patients receiving the slider and tensioner exercises showed a greater decrease in pain at the third and sixth sessions (mean difference: ≥1.54 cm; 95% CI, 0.1-3.9). There was a significant difference in the ROM of the SLR test between the slider and controls at only the sixth session (mean difference: 16.7°; 95% CI, -29.2 to -4.3). Patients in the slider and tensioner groups demonstrated greater improvements in the ROM of slump test at all sessions compared with controls (mean difference: ≥12.5°; 95% CI, -32.1 to -6.4). There were no significant differences between the slider and tensioner groups in any outcome at any session.

Conclusion

Patients in both slider and tensioner neural mobilization exercise groups demonstrated improvements in pain and ROM in patients with low back-related leg pain with peripheral nerve sensitization compared to those in the control group.

Transcutaneous Electrical Nerve Stimulation: A Review of Dental Applications

Transcutaneous electrical nerve stimulation or TENS is a nonpharmacologic method that is used to alleviate pain from various acute and chronic conditions. TENS works through activation of descending inhibitory neurons of the central nervous system. In dentistry, TENS has applications for pain reduction in temporomandibular disorders and postherpetic neuralgia. It has also been studied for its role in increasing salivary secretion in subjects with xerostomia and as a local anesthetic agent in pediatric dentistry. Its wide applications in the orofacial region make it an important treatment modality. The purpose of the present review was to describe the general principles and its applications in dentistry along with its indications, advantages, and disadvantages. A web-based search was conducted using the keywords “transcutaneous electrical nerve stimulation,” “temporomandibular joint,” “TENS,” “TMJ,” “orofacial pain,” and “Management.” The manuscripts thus obtained were evaluated and used for compiling the present narrative review. The present review focuses on the mechanism of action, applications, and effectiveness of TENS in the management of diseases of the maxillofacial region.

The Use of Electrical Nerve Stimulation to Treat Migraines: A Systematic Review

Migraines have been defined as an intense unilateral throbbing or pulsating sensation lasting anywhere between a few hours to multiple days. They are the sixth most prevalent disease in the United States, with approximately 18% of women and 6% of men experiencing some form of a migraine throughout their lifetime. In addition, they pose a significant economic burden, accounting for anywhere between $13 and $17 billion in medical costs annually in the United States. While there are a wide variety of treatments for migraines on the market, such as nonsteroidal anti-inflammatory drugs (NSAIDS), beta-blockers, and anti-epileptics, there is still no standard treatment. Moreover, each of these medications has a wide range of side effects, ranging from stomach ulcers to light-headedness. Within the last few decades, the presence of electrical nerve stimulation has emerged as a possible treatment option. These methods are almost free of harmful side effects and may be able to reduce the economic burden on those who suffer from migraines. However, studies have shown mixed results in regard to their efficacy. In this paper, we performed a systematic review to detail the current state of the literature regarding electrical nerve stimulation as a treatment modality for migraines.

Does Functional Neuromuscular Electrical Stimulation (NMES) Influence Calf Atrophy Following Achilles Tendon Surgery? Prospective Double-Blind Randomized Controlled Trial on the Use of Immediate Postoperative Electrical Muscle Stimulation to Preserve Muscle Function and Volume

Surgical repair of the Achilles tendon can lead to prolonged calf atrophy and functional limitations, even with early weightbearing. The use of neuromuscular electrical stimulation (NMES) has been studied in muscle rehabilitation programs following anterior cruciate ligament repair. Accelerated recovery and pain reduction were noted. The aim of the present study was to evaluate the use of electrical stimulation on maintaining calf muscle cross-sectional area volume and improving patient reported outcome measures following Achilles tendon surgery. Randomized controlled clinical trial. Forty patients were enrolled. All patients had undergone repair of the Achilles tendon. A 4 lead NMES device was applied at time of surgery with both patient and surgeon blinded to activity of the device. All patients followed a standardized postoperative protocol. Group 1 consisted of 20 patients who received protocol specific NMES. Group 2 was the "sham device" control group, receiving subtherapeutic electrical stimulation. Preoperative and postoperative calf circumference (2, 6, 12 weeks) and magnetic resonance imaging (MRI) scans (2, 6 weeks) were conducted. Patient-reported functional outcome scores were measured. Of the 40 patients, 23 (57.5%) were male and 17 (42.5%) were female. The mean age was 48.9 years (11.1 standard deviation [SD]) with a mean body mass index of 32.2 kg/m² (5.7 SD). Calf measurements for Group 1 (39.3 cm and 39.7 cm) were slightly higher compared Group 2 (38.4 cm and 39.2 cm) at 6 and 12 weeks postoperative. Functional scores were similar between Groups 1 and 2 at final follow-up. Foot/Ankle Computer Adaptive Test scores were 55.1 (6.9 SD) versus 58.4(8.6 SD), and American Orthopaedic Foot and Ankle Society Ankle-Hindfoot scores were 82.3 (8.2 SD) and 83.9 (9.3 SD), respectively. The visual analog scale at 12-week visit for Groups 1 and 2 was 8.4 (9.3 SD) and 8.4 (9.1 SD), respectively. This prospective randomized controlled trial was undertaken to quantify and validate the effect and ability of NMES to minimize calf atrophy after acute or chronic repair. No statistically significant difference was found between active NMES and sham control group. There was a trend showing some maintenance of calf volume per MRI study.

Parameterization of physical properties of layered body structure into equivalent circuit model

Background

This study presents a novel technique to develop an equivalent circuit model (ECM) for analyzing the responses of the layered body structure to transcutaneous electrical nerve stimulation (TENS) by parameterizing electrical and geometrical properties.Many classical ECMs are non-parametric because of the difficulty in projecting intrapersonal variability in the physical properties into ECM. However, not considering the intrapersonal variability hampers patient-specifically analyzing the body response to TENS and personal optimization of TENS parameter design. To overcome this limitation, we propose a tissue property-based (TPB) approach for the direct parameterization of the physical properties in the layered body structure and thus enable to quantify the effects of intrapersonal variability.

Results

The proposed method was first validated through in vitro phantom studies and then was applied in-vivo to analyze the TENS on the forearm. The TPB-ECM calculated the impedance network in the forearm and corresponding responses to TENS. In addition, the modelled impedance was in good agreement with well-known impedance properties that have been achieved empirically.

Conclusions

The TPB approach uses the parameterized circuit components compared to non-parametric conventional ECMs, thus overcoming the intrapersonal variability problem of the conventional ECMs. Therefore, the TPB-ECM has a potential for widely-applicable TENS analysis and could provide impactful guidance in the TENS parameter design.

Supplementary Information

The online version contains supplementary material available at (10.1186/s42490-021-00054-8).

Supraspinal neural mechanisms of the analgesic effect produced by transcutaneous electrical nerve stimulation

Although the analgesic effects of conventional transcutaneous electrical nerve stimulation (TENS) and acupuncture-like TENS are evident, their respective neural mechanisms in humans remain controversial. To elucidate and compare the supraspinal neural mechanisms of the analgesic effects produced by conventional TENS (high frequency and low intensity) and acupuncture-like TENS (low frequency and high intensity), we employed a between-subject sham-controlled experimental design with conventional, acupuncture-like, and sham TENS in 60 healthy human volunteers. In addition to assessing the TENS-induced changes of subjective ratings of perceived pain, we examined the TENS associated brainstem activities (fractional amplitude of low frequency fluctuations, fALFF) and their corresponding resting state functional connectivity (RSFC) with higher-order brain areas using functional magnetic resonance imaging. The analgesic effect of conventional TENS was only detected in the forearm that received TENS, coupled with decreased pons activity and RSFC between pons and contralateral primary somatosensory cortex. In contrast, acupuncture-like TENS produced a spatially diffuse analgesic effect, coupled with increased activities in both subnucleus reticularis dorsalis (SRD) and rostral ventromedial medulla (RVM), and decreased RSFC between SRD and medial frontal regions as well as between SRD and lingual gyrus. To sum up, our data demonstrated that conventional TENS and acupuncture-like TENS have different analgesic effects, which are mediated by different supraspinal neural mechanisms.

Transcutaneous electrical nerve stimulation for advanced cancer pain inpatients in specialist palliative care-a blinded, randomized, sham-controlled pilot cross-over trial

PURPOSE

Transcutaneous electrical nerve stimulation (TENS) is a treatment option for cancer pain, but the evidence is inconclusive. We aimed to evaluate the efficacy and safety of TENS.

METHODS

A blinded, randomized, sham-controlled pilot cross-over trial (NCT02655289) was conducted on an inpatient specialist palliative care ward. We included adult inpatients with cancer pain ≥ 3 on an 11-point numerical rating scale (NRS). Intensity-modulated high TENS (IMT) was compared with placebo TENS (PBT). Patients used both modes according to their preferred application scheme during 24 h with a 24-h washout phase. The primary outcome was change in average pain intensity on the NRS during the preceding 24 h. Responders were patients with at least a "slight improvement."

RESULTS

Of 632 patients screened, 25 were randomized (sequence IMT-PBT = 13 and PBT-IMT = 12). Finally, 11 patients in IMT-PBT and 9 in PBT-IMT completed the study (N = 20). The primary outcome did not differ between groups (IMT minus PBT: - 0.2, 95% confidence interval - 0.9 to 0.6). However, responder rates were higher in IMT (17/20 [85%] vs. 10/20 [50%], p = 0.0428). Two patients experienced an uncomfortable feeling caused by the current, one after IMT and one after PBT. Seven patients (35%) desired a TENS prescription. Women and patients with incident pain were most likely to benefit from TENS.

CONCLUSION

TENS was safe, but IMT was unlikely to offer more analgesic effects than PBT. Even though many patients desired a TENS prescription, 50% still reported at least "slight pain relief" from PBT. Differences for gender and incident pain aspects demand future trials.

Respiration-driven triboelectric nanogenerators for biomedical applications

As a fundamental and ubiquitous body motion, respiration offers a large amount of biomechanical energy with an average power up to the Watt level through movements of multiple muscles. The energy from respiration featured with excellent stability, accessibility and continuality inspires the design and engineering of biomechanical energy harvesting devices, such as triboelectric nanogenerators (TENGs), to realize human-powered electronics. This review article is thus dedicated to the emerging respiration-driven TENG technology, covering fundamentals, applications, and perspectives. Specifically, the human breathing mechanics are first introduced serving as the base for the developments of TENG devices with different configurations. Biomedical applications including electrical energy generation, healthcare monitoring, air filtration, gas sensing, electrostimulation, and powering implantable medical devices are then analyzed focusing on the design-application relationships. At last, current developments are summarized and critical challenges for driving these intriguing developments toward practical applications are discussed together with promising solutions.

The effect of tens for pain relief in women with primary dysmenorrhea: A systematic review and meta-analysis

OBJECTIVE

Primary dysmenorrhea (PD) is a chronic health condition that affects primarily young women and interferes with daily activities, causes loss of work productivity, and reduces quality of life. Transcutaneous electrical nerve stimulation (TENS) is a complementary and alternative therapy used to reduce pain related to PD. The purpose of this meta-analysis study was to evaluate the effectiveness of TENS in the treatment of pain in women with PD.

METHODS

A search of the English literature in the Cochrane Library, MEDLINE (EBSCO), Physiotherapy Evidence Database (PEDro), CINAHL (EBSCO), PUBMED, OVID, Science Direct, Scopus, Academic Search Complete databases was conducted using combinations of the following search terms: 'primary dysmenorrhea', 'pain', 'transcutaneous electrical nerve stimulation', 'TENS', and 'electrical stimulation'. All content from database inception through April 2020 was included in the search.

RESULTS

The initial search strategy based on date range and language yielded 571 relevant records and 4 of them were about both TENS and PD. A total of 260 patients were enrolled in the included studies. In all of the included studies, the comparison intervention consisted of sham TENS. The primary outcome of interest was pain intensity. Our analysis indicated that TENS was statistically more effective than sham TENS in reducing PD-related pain (SMD=1.384; 95% CI=0.505, 2.262; p = 0.002).

CONCLUSION

TENS is a safe and well-tolerated electrophysical therapy that may be effective for relieving pain in PD.

Electrical stimulation of cranial nerves in cognition and disease

The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.

Identifying the Role of Block Length in Neural Heat Block to Reduce Temperatures During Infrared Neural Inhibition

BACKGROUND AND OBJECTIVES

The objective of this study is to assess the hypothesis that the length of axon heated, defined here as block length (BL), affects the temperature required for thermal inhibition of action potential propagation applied using laser heating. The presence of such a phenomenon has implications for how this technique, called infrared neural inhibition (INI), may be applied in a clinically safe manner since it suggests that temperatures required for therapy may be reduced through the proper spatial application of light. Here, we validate the presence of this phenomenon by assessing how the peak temperatures during INI are reduced when two different BLs are applied using irradiation from either one or two adjacent optical fibers.

STUDY DESIGN/MATERIALS AND METHODS

Assessment of the role of BL was carried out over two phases. First, a computational proof of concept was performed in the neural conduction simulation environment, NEURON, simulating the response of action potentials to increased temperatures applied at different full-width at half-maxima (FWHM) along axons. Second, ex vivo validation of these predictions was performed by measuring the radiant exposure, peak temperature rise, and FWHM of heat distributions associated with INI from one or two adjacent optical fibers. Electrophysiological assessment of radiant exposures at inhibition threshold were carried out in ex vivo Aplysia californica (sea slug) pleural abdominal nerves ( n = 6), an invertebrate with unmyelinated axons. Measurement of the maximum temperature rise required for induced heat block was performed in a water bath using a fine wire thermocouple. Finally, magnetic resonance thermometry (MRT) was performed on a nerve immersed in saline to assess the elevated temperature distribution at these radiant exposures.

RESULTS

Computational modeling in NEURON provided a theoretical proof of concept that the BL is an important factor contributing to the peak temperature required during neural heat block, predicting a 11.7% reduction in temperature rise when the FWHM along an axon is increased by 42.9%. Experimental validation showed that, when using two adjacent fibers instead of one, a 38.5 ± 2.2% (mean ± standard error of the mean) reduction in radiant exposure per pulse per fiber threshold at the fiber output (P = 7.3E-6) is measured, resulting in a reduction in peak temperature rise under each fiber of 23.5  ± 2.1% ( P = 9.3E-5) and 15.0 ± 2.4% ( P = 1.4E-3) and an increase in the FWHM of heating by 37.7 ± 6.4% ( P = 1E-3), 68.4 ± 5.2% ( P = 2.4E-5), and 51.9  ± 9.9% ( P = 1.7E-3) in three MRT slices.

CONCLUSIONS

This study provides the first experimental evidence for a phenomenon during the heat block in which the temperature for inhibition is dependent on the BL. While more work is needed to further reduce the temperature during INI, the results highlight that spatial application of the temperature rise during INI must be considered. Optimized implementation of INI may leverage this cellular response to provide optical modulation of neural signals with lower temperatures over greater time periods, which may increase the utility of the technique for laboratory and clinical use. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Different electrode positioning for transcutaneous electrical nerve stimulation in the treatment of urgency in women: a study protocol for a randomized controlled clinical trial

BACKGROUND

Urgency is a complaint of sudden, compelling desire to pass urine, which is difficult to defer, caused by involuntary contraction of the detrusor muscle during the bladder-filling stage. To enable detrusor inhibition, electrotherapy resources such as transcutaneous tibial nerve stimulation (TTNS) and parasacral transcutaneous electrical stimulation (PTES) have been used. The objective this study is to publish the study protocol that aims to investigate whether urgency decreases after treatment with both of the techniques.

METHODS

This randomized controlled clinical trial will include 99 women, aged more than 18 years old, with urgency (score ≥ 8 in the Overactive Bladder-Validated 8-Question Awareness Tool [OAB-V8]). Women will be randomly allocated into three groups: TTNS, PTES, and placebo. The following questionnaires will be applied: the Anamnesis Record, the Incontinence Questionnaire Overactive Bladder, the King's Health Questionnaire, the 24-Hour Voiding Diary, and the OAB-V8, at four different time points: at baseline prior to the first session, at the 6th session, the 12th session and at follow-up. The current used for the transcutaneous electrical stimulation will be a symmetrical balanced biphasic pulsed current, for 12 sessions, twice a week, for 20 minutes. Qualitative variables will be displayed as frequency and percentage, quantitative variables as mean and standard deviation. Comparison of urgency severity among groups will be performed with a repeated measures ANOVA, considering the effect of the three groups and the four evaluations, and interactions among them.

DISCUSSION

The present study aims to contribute evidence for a more in-depth discussion on electrode positioning for electrostimulation used in urgency treatment. It should be emphasized that, based on the possibility of confirming the hypothesis that urgency will decrease in a similar way after both treatments (TTNS and PTES), the PTES will be used as an option for positioning the electrodes alternatively to the tibial nerve region in special populations, such as amputees or people with severe lower limb sensory impairment.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (ReBEC) ID: RBR-9rf33n, date of registration: 17 May 2018.

A Narrative Review of the Use of Neuromuscular Electrical Stimulation in Individuals With Diabetic Foot Ulceration

This review aims to summarize the evidence reported on the use of neuromuscular electrical stimulation (NMES) in individuals with diabetic foot ulceration (DFU). A systematic search of EMBASE and MEDLINE databases was performed in February 2019, using search terms relating to the domains DFU and NMES. All primary evidence assessing outcomes of NMES in DFU were included. Of 344 references obtained from database searching, 7 met the inclusion criteria and included a total of 140 participants, 77 of whom had DFU. All included studies used prospective designs. Two studies demonstrated improvements in chronic ulcer healing with NMES use; however, in each study, only 3 of the included participants had DFU and subgroup analyses based on ulcer etiology was omitted. The remaining 5 studies were produced by the same research group and positive effects of NMES (in combination with heat therapy) on DFU healing were consistently demonstrated. They reported significantly better healing rates with NMES in DFU than in nondiabetic wounds of a similar grade (healing rate: 70.0 ± 32.3% in DFU vs 38.4 ± 22.3% in nondiabetic ulcers [ P < .01]). These studies did not provide data assessing the isolated effects of NMES without concomitant heat exposure. Data on device tolerability and compliance were lacking. The existing data support a potential role for NMES in individuals with DFU; however, the identified studies inadequately controlled for confounding and were underpowered. Given the significant morbidity and mortality associated with DFU, higher quality evidence is needed to assess the adjunctive role for NMES in this group.

A randomized trial comparing the Tennant Biomodulator to transcutaneous electrical nerve stimulation and traditional Chinese acupuncture for the treatment of chronic pain in military service members

BACKGROUND

The present investigation tested the efficacy of the Tennant Biomodulator, a novel pain management intervention that uses biofeedback-modulated electrical stimulation, to reduce chronic pain and its psychosocial sequelae in a sample of current and former military service members. The Tennant Biomodulator used on its most basic setting was compared to two commonly used, non-pharmacological pain treatments-traditional Chinese acupuncture and transcutaneous electrical nerve stimulation (TENS)-in a comparative efficacy, randomized, open-label trial.

METHODS

Participants included 100 active duty and retired service men and women with chronic pain undergoing treatment at the Brooke Army Medical Center in Texas, USA, randomly assigned to receive six, weekly sessions of either Tennant Biomodulator treatment, traditional Chinese acupuncture, or TENS, in addition to usual care. Recruitment was conducted between May 2010 to September 2013. Outcome measures were collected at intake, before and after each treatment session, and at a 1-month follow-up. Intent-to-treat analyses were used throughout, with mixed models used to investigate main effects of group, time, and group × time interactions with consideration given to quadratic effects. Outcomes measured included ratings of chronic pain, pain-related functional disability, and symptoms of post-traumatic stress disorder (PTSD) and depression.

RESULTS

On average, regardless of their treatment group, participants exhibited a 16% reduction in pain measured by the Brooke Army Medical Center's Clinic Pain Log [F(1, 335) = 55.7, P <  0.0001] and an 11% reduction in pain-related disability measured by the Million Visual Analog Scale [MVAS: F(1, 84) = 28.3, P <  0.0001] from baseline to the end of treatment, but no one treatment performed better than the other, and the reductions in pain and pain-related disability were largely lost by 1-month follow-up. Symptoms of PTSD and depression did not change significantly as a function of time or group.

CONCLUSIONS

Findings build on previous work suggesting that traditional Chinese acupuncture and TENS can reduce pain and its functional sequelae without risks associated with pharmacological pain management. The Tennant Biomodulator used on its most basic setting performs as well as these other interventions. Based on the present findings, large, randomized controlled trials on the Tennant Biomodulator are indicated. Future work should test this device using its full range of settings for pain-related psychological health.

TRIAL REGISTRATION

Clincialtrials.gov (NCT01752010); registered December 14, 2012.

The effect of adding TENS to stretch on improvement of ankle range of motion in inactive patients in intensive care units: a pilot trial

Background

Patients hospitalized in intensive care units (ICUs) are susceptible to joint contracture and diminished range of motion. This is due to immobility as well as other underlying factors such as brain damage. Joint contracture causes functional disorders thereby diminishing the quality of life of patients following the intensive care period. Recent studies have introduced transcutaneous electrical nerve stimulation (TENS) as a new method for preventing and treating joint contracture. This study was performed to determine the effect of adding TENS to stretch on the range of ankle motion in patients hospitalized in ICUs.

Methods

Thirty-six patients admitted to the ICU ward of the hospital who were not able to move their legs voluntarily were assigned randomly into experimental (n = 18) and control (n = 18) groups. The intervention group received TENS along with manual stretch in the ankle three times a week for 2 weeks. The control group only received stretch in the ankle for the same time. The extent of dorsiflexion and plantar flexion of the ankle was measured using a standard goniometer. Both groups were evaluated before and one and 2 weeks after the intervention. The obtained data were analyzed by SPSS 21 through analysis of covariance and repeated measures ANOVA tests.

Results

In both groups, the increase in the ankle range of motion parameters was significant over time (means ranged over 44–48 for plantar flexion and means ranged over 5–11 for dorsiflexion, P < 0.001 for all of time points). The increase in ankle plantar and dorsiflexion in experimental group was significantly more than control group (mean between-group differences ranged over 1.35–3.57 within 95% CI of 1.04 to 4.01, P < 0.001).

Conclusion

Adding TENS to stretch may provide more improvement in ankle dorsiflexion and plantar flexion.

Trial registration

Trial registration: This study was registered in the Iranian Clinical Trial Center with the code IRCT2017010814333N64, registered 20 January 2017.

Efficacy and mode of action of external trigeminal neurostimulation in migraine

INTRODUCTION

Available preventive drug treatments for migraine lack complete efficacy and often have unpleasant adverse effects. Hence, their clinical utility and therapeutic adherence are limited. Noninvasive neurostimulation methods applied over various peripheral sites (forehead, mastoid, upper arm, cervical vagus nerve) have raised great interest because of their excellent efficacy/tolerance profile. Among them external trigeminal nerve stimulation (eTNS) was first to obtain FDA approval for migraine therapy. Areas covered: All clinical trials of eTNS as preventive or acute migraine treatment published in extenso or presented at congresses are reviewed. The paper analyzes neuroimaging and neurophysiological studies on mechanisms of action of eTNS. As many of these studies point toward the anterior cingulate cortex (ACC) as a likely eTNS target, the paper scrutinizes the available literature on the ACC implication in migraine pathophysiology. Expert commentary: eTNS is a viable alternative to standard pharmacological antimigraine strategies both for prevention and abortive therapy. eTNS could chiefly exert its action by modulating the perigenual ACC, which might also be of interest for treating other disorders like fibromyalgia or depression. It remains to be determined if this might be a common mechanism to other peripheral noninvasive neurostimulation methods.

Differential efficiency of transcutaneous electrical nerve stimulation in dominant versus nondominant hands in fibromyalgia: placebo-controlled functional near-infrared spectroscopy study

Using functional near-infrared spectroscopy (fNIRS), modulation of hemodynamic responses by transcutaneous electrical nerve stimulation (TENS) during delivery of nociceptive stimulation was investigated in fibromyalgia (FM) patients and healthy controls for both hands. Two experiments were conducted: (1) median nerve stimulation with TENS and (2) painful stimulation using electronic von Frey filaments with TENS/placebo TENS. Mean [Formula: see text] brain activity was compared across groups and conditions using factorial ANOVA. Dominant (right) hand stimulation indicated significant interactions between group and condition in both hemispheres. Post hoc results revealed that FM patients showed an increased activation in "pain + TENS" condition compared to the "pain + placebo TENS" condition while the brain activity patterns for these conditions in controls were reversed. Left-hand stimulation resulted in similar TENS effects (reduced activation for "pain + TENS" than "pain + placebo TENS") in both groups. TENS effects in FM patients might be manipulated by the stimulation side. While the nondominant hand was responsive to TENS treatment, the dominant hand was not. These results indicate that stimulation side might be an effective factor in FM treatment by using TENS. Future studies are needed to clarify the underlying mechanism for these findings.

Cameo surface recording in complete denture fabrication using transcutaneous electrical nerve stimulation: A clinical report

Severe bone loss in patients with complete edentulism poses a treatment challenge. In fabricating a denture, the stability of the prosthesis must be enhanced by recording the cameo surface within the confines of the physiological position of the cheek and tongue muscles (the neutral zone) and by shaping it accordingly. The treatment of a patient with a completely edentulous maxillary arch and severe maxillary anterior bone loss is described. The cameo surface was recorded within the physiological limits during the fabrication of a complete denture by using transcutaneous electrical nerve stimulation (TENS).

Electro-analgesia for sheep husbandry practices: a review

Several sheep-husbandry practices such as mulesing, castration, ear-tagging and tail-docking are currently performed with no, or little, anaesthesia or analgesia. The potential for using electrotherapies to provide analgesia during and after these operations is examined in this review. The most common electrotherapy is transcutaneous electrical nerve stimulation (TENS). TENS is the application of an electrical current from electrodes placed on the skin. Analysis of a large number of trials in humans and in animal models indicates that TENS provides effective relief from acute and chronic pain, including pain associated with surgery. There is strong evidence now that TENS analgesia operates at the levels of the periphery, the spinal cord and in the brain. The mechanisms involve the autonomic nervous system, the opioid pathways and neurotransmitters involved in descending inhibitory pathways from the brain. Centrally operating pathways mean the current does not have to be applied near the injured site and there is evidence of sustained pain relief lasting hours, days or even weeks post-treatment, particularly after very high-frequency, randomly variable current applications. Treatment of sheep during painful operations with such a current has the potential to provide immediate and possibly sustained pain relief. Combining such a treatment with electro-immobilisation of the animal would be advantageous for sheep-husbandry operations, but there is considerable evidence that high-intensity currents producing tetanic contractions are aversive and probably painful for sheep. Investigations of the application and efficacy of electrotherapies for painful sheep operations should be undertaken.

Electrotherapy modalities for rotator cuff disease

BACKGROUND

Management of rotator cuff disease may include use of electrotherapy modalities (also known as electrophysical agents), which aim to reduce pain and improve function via an increase in energy (electrical, sound, light, or thermal) into the body. Examples include therapeutic ultrasound, low-level laser therapy (LLLT), transcutaneous electrical nerve stimulation (TENS), and pulsed electromagnetic field therapy (PEMF). These modalities are usually delivered as components of a physical therapy intervention. This review is one of a series of reviews that form an update of the Cochrane review, 'Physiotherapy interventions for shoulder pain'.

OBJECTIVES

To synthesise available evidence regarding the benefits and harms of electrotherapy modalities for the treatment of people with rotator cuff disease.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015, Issue 3), Ovid MEDLINE (January 1966 to March 2015), Ovid EMBASE (January 1980 to March 2015), CINAHL Plus (EBSCOhost, January 1937 to March 2015), ClinicalTrials.gov and the WHO ICTRP clinical trials registries up to March 2015, unrestricted by language, and reviewed the reference lists of review articles and retrieved trials, to identify potentially relevant trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-randomised trials, including adults with rotator cuff disease (e.g. subacromial impingement syndrome, rotator cuff tendinitis, calcific tendinitis), and comparing any electrotherapy modality with placebo, no intervention, a different electrotherapy modality or any other intervention (e.g. glucocorticoid injection). Trials investigating whether electrotherapy modalities were more effective than placebo or no treatment, or were an effective addition to another physical therapy intervention (e.g. manual therapy or exercise) were the main comparisons of interest. Main outcomes of interest were overall pain, function, pain on motion, patient-reported global assessment of treatment success, quality of life and the number of participants experiencing adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted the data, performed a risk of bias assessment and assessed the quality of the body of evidence for the main outcomes using the GRADE approach.

MAIN RESULTS

We included 47 trials (2388 participants). Most trials (n = 43) included participants with rotator cuff disease without calcification (four trials included people with calcific tendinitis). Sixteen (34%) trials investigated the effect of an electrotherapy modality delivered in isolation. Only 23% were rated at low risk of allocation bias, and 49% were rated at low risk of both performance and detection bias (for self-reported outcomes). The trials were heterogeneous in terms of population, intervention and comparator, so none of the data could be combined in a meta-analysis.In one trial (61 participants; low quality evidence), pulsed therapeutic ultrasound (three to five times a week for six weeks) was compared with placebo (inactive ultrasound therapy) for calcific tendinitis. At six weeks, the mean reduction in overall pain with placebo was -6.3 points on a 52-point scale, and -14.9 points with ultrasound (MD -8.60 points, 95% CI -13.48 to -3.72 points; absolute risk difference 17%, 7% to 26% more). Mean improvement in function with placebo was 3.7 points on a 100-point scale, and 17.8 points with ultrasound (mean difference (MD) 14.10 points, 95% confidence interval (CI) 5.39 to 22.81 points; absolute risk difference 14%, 5% to 23% more). Ninety-one per cent (29/32) of participants reported treatment success with ultrasound compared with 52% (15/29) of participants receiving placebo (risk ratio (RR) 1.75, 95% CI 1.21 to 2.53; absolute risk difference 39%, 18% to 60% more). Mean improvement in quality of life with placebo was 0.40 points on a 10-point scale, and 2.60 points with ultrasound (MD 2.20 points, 95% CI 0.91 points to 3.49 points; absolute risk difference 22%, 9% to 35% more). Between-group differences were not important at nine months. No participant reported adverse events.Therapeutic ultrasound produced no clinically important additional benefits when combined with other physical therapy interventions (eight clinically heterogeneous trials, low quality evidence). We are uncertain whether there are differences in patient-important outcomes between ultrasound and other active interventions (manual therapy, acupuncture, glucocorticoid injection, glucocorticoid injection plus oral tolmetin sodium, or exercise) because the quality of evidence is very low. Two placebo-controlled trials reported results favouring LLLT up to three weeks (low quality evidence), however combining LLLT with other physical therapy interventions produced few additional benefits (10 clinically heterogeneous trials, low quality evidence). We are uncertain whether transcutaneous electrical nerve stimulation (TENS) is more or less effective than glucocorticoid injection with respect to pain, function, global treatment success and active range of motion because of the very low quality evidence from a single trial. In other single, small trials, no clinically important benefits of pulsed electromagnetic field therapy (PEMF), microcurrent electrical stimulation (MENS), acetic acid iontophoresis and microwave diathermy were observed (low or very low quality evidence).No adverse events of therapeutic ultrasound, LLLT, TENS or microwave diathermy were reported by any participants. Adverse events were not measured in any trials investigating the effects of PEMF, MENS or acetic acid iontophoresis.

AUTHORS' CONCLUSIONS

Based on low quality evidence, therapeutic ultrasound may have short-term benefits over placebo in people with calcific tendinitis, and LLLT may have short-term benefits over placebo in people with rotator cuff disease. Further high quality placebo-controlled trials are needed to confirm these results. In contrast, based on low quality evidence, PEMF may not provide clinically relevant benefits over placebo, and therapeutic ultrasound, LLLT and PEMF may not provide additional benefits when combined with other physical therapy interventions. We are uncertain whether TENS is superior to placebo, and whether any electrotherapy modality provides benefits over other active interventions (e.g. glucocorticoid injection) because of the very low quality of the evidence. Practitioners should communicate the uncertainty of these effects and consider other approaches or combinations of treatment. Further trials of electrotherapy modalities for rotator cuff disease should be based upon a strong rationale and consideration of whether or not they would alter the conclusions of this review.

Treatment of Female Sexual Pain Disorders: A Systematic Review

Sexual pain disorders affect women's sexual and reproductive health and are poorly understood. Although many treatments have been evaluated, there is no one "gold standard" treatment. The aim of this systematic review was to investigate what treatments for female sexual pain have been evaluated in clinical studies and their effectiveness. The search strategy resulted in 65 papers included in this review. The articles were divided into the following categories: medical treatments; surgical treatments; physical therapies; psychological therapies; comparative treatment studies; and miscellaneous and combined treatments. Topical and systemic medical treatments have generally been found to lead to improvements in, but not complete relief of, pain, and side effects are quite common. Surgical procedures have demonstrated very high success rates, although there has been variability in complete relief of pain after surgery, which suggests less invasive treatments should be considered first. Physical therapies and psychological therapies have been shown to be promising treatments, supporting a biopsychosocial approach to sexual pain disorders. Although most of the interventions described have been reported as effective, many women still experience pain. A multidisciplinary team with active patient involvement may be needed to optimize treatment outcome.

Immediate effects of transcutaneous electrical stimulation on physiological swallowing effort in older versus young adults

OBJECTIVE

This study compared the immediate impact of different transcutaneous electrical stimulation (TES) amplitudes on physiological swallowing effort in healthy older adults versus young adults.

BACKGROUND

Swallowing physiology changes with age. Reduced physiological swallowing effort in older adults including lower lingua-palatal and pharyngeal pressures may increase risk for swallowing dysfunction (i.e. dysphagia). Transcutaneous electrical stimulation (TES) has been advocated as an adjunctive modality to enhance outcomes in exercise-based therapy for individuals with dysphagia. However, significant variation in how TES is applied during therapy remains and the physiological swallowing response to TES is poorly studied, especially in older adults.

MATERIALS AND METHODS

Physiological change in swallowing associated with no stimulation, sensory stimulation and motor stimulation was compared in 20 young adults versus 14 older adults. Lingua-palatal and pharyngeal manometric pressures assessed physiological swallowing effort.

RESULTS

Multivariate analyses identified interactions between age and stimulation amplitude on lingual and pharyngeal functions. Motor stimulation reduced anterior tongue pressure in both age groups but selectively reduced posterior lingua-palatal pressures in young adults only. Sensory stimulation increased base of tongue (BOT) pressures in older adults but decreased BOT pressures in young adults. Motor stimulation increased hypopharyngeal pressures in both groups.

CONCLUSION

Age and TES level interact in determining immediate physiological responses on swallow performance. A one-size-fit-all approach to TES in dysphagia rehabilitation may be misdirected.

Electrotherapy modalities for adhesive capsulitis (frozen shoulder)

BACKGROUND

Adhesive capsulitis (also termed frozen shoulder) is a common condition characterised by spontaneous onset of pain, progressive restriction of movement of the shoulder and disability that restricts activities of daily living, work and leisure. Electrotherapy modalities, which aim to reduce pain and improve function via an increase in energy (electrical, sound, light, thermal) into the body, are often delivered as components of a physical therapy intervention. This review is one in a series of reviews which form an update of the Cochrane review 'Physiotherapy interventions for shoulder pain'.

OBJECTIVES

To synthesise the available evidence regarding the benefits and harms of electrotherapy modalities, delivered alone or in combination with other interventions, for the treatment of adhesive capsulitis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, EMBASE, CINAHL Plus and the ClinicalTrials.gov and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) clinical trials registries up to May 2014, unrestricted by language, and reviewed the reference lists of review articles and retrieved trials to identify any other potentially relevant trials.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled clinical trials using a quasi-randomised method of allocation that included adults with adhesive capsulitis and compared any electrotherapy modality to placebo, no treatment, a different electrotherapy modality, or any other intervention. The two main questions of the review focused on whether electrotherapy modalities are effective compared to placebo or no treatment, or if they are an effective adjunct to manual therapy or exercise (or both). The main outcomes of interest were participant-reported pain relief of 30% or greater, overall pain, function, global assessment of treatment success, active shoulder abduction, quality of life, and the number of participants experiencing any adverse event.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted the data, performed a risk of bias assessment, and assessed the quality of the body of evidence for the main outcomes using the GRADE approach.

MAIN RESULTS

Nineteen trials (1249 participants) were included in the review. Four trials reported using an adequate method of allocation concealment and six trials blinded participants and personnel. Only two electrotherapy modalities (low-level laser therapy (LLLT) and pulsed electromagnetic field therapy (PEMF)) have been compared to placebo. No trial has compared an electrotherapy modality plus manual therapy and exercise to manual therapy and exercise alone. The two main questions of the review were investigated in nine trials.Low quality evidence from one trial (40 participants) indicated that LLLT for six days may result in improvement at six days. Eighty per cent (16/20) of participants reported treatment success with LLLT compared with 10% (2/20) of participants receiving placebo (risk ratio (RR) 8.00, 95% confidence interval (CI) 2.11 to 30.34; absolute risk difference 70%, 95% CI 48% to 92%). No participants in either group reported adverse events.We were uncertain whether PEMF for two weeks improved pain or function more than placebo at two weeks because of the very low quality evidence from one trial (32 participants). Seventy-five per cent (15/20) of participants reported pain relief of 30% or more with PEMF compared with 0% (0/12) of participants receiving placebo (RR 19.19, 95% CI 1.25 to 294.21; absolute risk difference 75%, 95% CI 53% to 97%). Fifty-five per cent (11/20) of participants reported total recovery of joint function with PEMF compared with 0% (0/12) of participants receiving placebo (RR 14.24, 95% CI 0.91 to 221.75; absolute risk difference 55%, 95% CI 31 to 79).Moderate quality evidence from one trial (63 participants) indicated that LLLT plus exercise for eight weeks probably results in greater improvement when measured at the fourth week of treatment, but a similar number of adverse events, compared with placebo plus exercise. The mean pain score at four weeks was 51 points with placebo plus exercise, while with LLLT plus exercise the mean pain score was 32 points on a 100 point scale (mean difference (MD) 19 points, 95% CI 15 to 23; absolute risk difference 19%, 95% CI 15% to 23%). The mean function impairment score was 48 points with placebo plus exercise, while with LLLT plus exercise the mean function impairment score was 36 points on a 100 point scale (MD 12 points, 95% CI 6 to 18; absolute risk difference 12%, 95% CI 6 to 18). Mean active abduction was 70 degrees with placebo plus exercise, while with LLLT plus exercise mean active abduction was 79 degrees (MD 9 degrees, 95% CI 2 to 16; absolute risk difference 5%, 95% CI 1% to 9%). No participants in either group reported adverse events. LLLT's benefits on function were maintained at four months.Based on very low quality evidence from six trials, we were uncertain whether therapeutic ultrasound, PEMF, continuous short wave diathermy, Iodex phonophoresis, a combination of Iodex iontophoresis with continuous short wave diathermy, or a combination of therapeutic ultrasound with transcutaneous electrical nerve stimulation (TENS) were effective adjuncts to exercise. Based on low or very low quality evidence from 12 trials, we were uncertain whether a diverse range of electrotherapy modalities (delivered alone or in combination with manual therapy, exercise, or other active interventions) were more or less effective than other active interventions (for example glucocorticoid injection).

AUTHORS' CONCLUSIONS

Based upon low quality evidence from one trial, LLLT for six days may be more effective than placebo in terms of global treatment success at six days. Based upon moderate quality evidence from one trial, LLLT plus exercise for eight weeks may be more effective than exercise alone in terms of pain up to four weeks, and function up to four months. It is unclear whether PEMF is more or less effective than placebo, or whether other electrotherapy modalities are an effective adjunct to exercise. Further high quality randomised controlled trials are needed to establish the benefits and harms of physical therapy interventions (that comprise electrotherapy modalities, manual therapy and exercise, and are reflective of clinical practice) compared to interventions with evidence of benefit (for example glucocorticoid injection or arthrographic joint distension).

Vascular Endothelial Growth Factor Release Following Electrical Stimulation in Human Subjects

Significance: Angiogenesis is an important phenomenon involved in the healing of chronic wounds, and it is mainly mediated by the release of vascular endothelial growth factor (VEGF) from endothelial cells. Electrical stimulation (ES) is a well-documented treatment used to assist the healing of chronic wounds. Due to the importance of VEGF in the healing process, and the need to know the mechanisms of action of ES involved in the process, this report aimed to determine by a literature review whether the VEGF release occurs following ES in human subjects. Recent Advances: The findings of this literature review suggest that ES releases VEGF, and this effect may be responsible for promoting angiogenesis after ES. Critical Issues: Despite the findings of this literature review on the release of VEGF by ES on wound healing are promising, a large number of studies are needed to confirm such effects. Future Directions: Further studies should be conducted to identify the best parameters and treatment schedule of ES to be used for the VEGF release.

An investigation into the magnitude of the current window and perception of transcutaneous electrical nerve stimulation (TENS) sensation at various frequencies and body sites in healthy human participants

INTRODUCTION

Strong nonpainful transcutaneous electrical nerve stimulation (TENS) is prerequisite to a successful analgesic outcome although the ease with which this sensation is achieved is likely to depend on the magnitude of current amplitude (mA) between sensory detection threshold (SDT) and pain threshold, that is, the current window.

OBJECTIVES

To measure the current window and participant's perception of the comfort of the TENS sensation at different body sites.

METHODS

A repeated measure cross-over study was conducted using 30 healthy adult volunteers. Current amplitudes (mA) of TENS [2 pulses per second (pps); 30 pps; 80 pps] at SDT, pain threshold, and strong nonpainful intensities were measured at the tibia (bone), knee joint (connective tissue), lower back [paraspinal (skeletal) muscle], volar surface of forearm (nerve) and waist (fat). The amplitude to achieve a strong nonpainful intensity was represented as a percentage of the current window. Data were analyzed using repeated measures analysis of variance.

RESULTS

Effects were detected for body site and frequency for SDT (P<0.001, P=0.018, respectively), current window (P<0.001, P<0.001, respectively), and strong nonpainful TENS as a percentage of the current window (P=0.002, P<0.001, respectively). The current window was larger for the knee joint compared with tibia (difference [95% confidence interval]=12.76 mA [4.25, 21.28]; P=0.001) and forearm (10.33 mA [2.62, 18.40]; P=0.006), and for the lower back compared with tibia (12.10 mA [1.65, 22.52]; P=0.015) and forearm (9.65 mA [1.06, 18.24]; P=0.019). The current window was larger for 2 pps compared with 30 pps (P<0.001) and 80 pps (P<0.001). Participants rated strong nonpainful TENS as most comfortable at the lower back (P<0.001) and least comfortable at the tibia and forearm (P<0.001).

CONCLUSIONS

TENS is most comfortable and easiest to titrate to a strong nonpainful intensity when applied over areas of muscle and soft tissue.

How to design the control group in randomized controlled trials of acupuncture?

In evidence-based medicine, randomized controlled trials (RCTs) are the preferred method for evaluating the efficacy of interventions. In regard to acupuncture RCTs, the most difficult issues are the design of the control group and implementation of the principle of “double-blinding.” We compared the advantages and limitations associated with different control group designs in acupuncture RCTs, to assist researchers in this field.

Transcutaneous electric nerve stimulation (TENS) for cancer pain in adults

BACKGROUND

Cancer-related pain is complex and multi-dimensional but the mainstay of cancer pain management has predominantly used a biomedical approach. There is a need for non-pharmacological and innovative approaches. Transcutaneous Electric Nerve Stimulation (TENS) may have a role in pain management but the effectiveness of TENS is currently unknown. This is an update of the original review published in Issue 3, 2008.

OBJECTIVES

The aim of this systematic review was to determine the effectiveness of TENS for cancer-related pain in adults.

SEARCH METHODS

The initial review searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, PsychINFO, AMED and PEDRO databases in April 2008. We performed an updated search of CENTRAL, MEDLINE, EMBASE, CINAHL and PEDRO databases in November 2011.

SELECTION CRITERIA

We included only randomised controlled trials (RCTS) investigating the use of TENS for the management of cancer-related pain in adults.

DATA COLLECTION AND ANALYSIS

The search strategy identified a further two studies for possible inclusion. One of the review authors screened each abstract using a study eligibility tool. Where eligibility could not be determined, a second author assessed the full paper. One author used a standardised data extraction sheet to collect information on the studies and independently assess the quality of the studies using the validated five-point Oxford Quality Scale. The small sample sizes and differences in patient study populations of the three included studies (two from the original review and a third included in this update) prevented meta-analysis. For the original review the search strategy identified 37 possible published studies; we divided these between two pairs of review authors who decided on study selection; all four review authors discussed and agreed final scores.

MAIN RESULTS

Only one additional RCT met the eligibility criteria (24 participants) for this updated review. Although this was a feasibility study, not designed to investigate intervention effect, it suggested that TENS may improve bone pain on movement in a cancer population. The initial review identified two RCTs (64 participants) therefore this review now includes a total of three RCTs (88 participants). These studies were heterogenous with respect to study population, sample size, study design, methodological quality, mode of TENS, treatment duration, method of administration and outcome measures used. In one RCT, there were no significant differences between TENS and placebo in women with chronic pain secondary to breast cancer treatment. In the other RCT, there were no significant differences between acupuncture-type TENS and sham in palliative care patients; this study was underpowered.

AUTHORS' CONCLUSIONS

Despite the one additional RCT, the results of this updated systematic review remain inconclusive due to a lack of suitable RCTs. Large multi-centre RCTs are required to assess the value of TENS in the management of cancer-related pain in adults.