Individuals with tetraplegia, typically attributed to spinal cord injuries (SCI) at the cervical level, experience significant health care costs and loss of independence due to their limited reaching ...and grasping capabilities. Neuromuscular electrical stimulation (NMES) is a promising intervention to restore arm and hand function because it activates a person's own paralyzed muscles; however, NMES sometimes lacks the accuracy and repeatability necessary to position the limb for functional tasks, and repeated muscle stimulation can lead to fatigue. Robotic devices have the potential to restore function when used as assistive devices to supplement or replace limited or lost function of the upper limb following SCI. Unfortunately, most robotic solutions are bulky or require significant power to operate, limiting their applicability to restore functional independence in a home environment. Combining NMES and robotic support systems into a single hybrid neuroprosthesis is compelling, since the robotic device can supplement the action of the muscles and improve repeatability and accuracy. Research groups have begun to explore applications of movement assistance for individuals with spinal cord injury using these technologies in concert. In this review, we present the state of the art in hybrid NMES-orthotic systems for upper limb movement restoration following spinal cord injury, and suggest areas for emphasis necessary to move the field forward. Currently, NMES-robotic systems use either surface or implanted electrodes to stimulate muscles, with rigid robotic supports holding the limb against gravity, or providing assistance in reaching movements. Usability of such systems outside of the lab or clinic is limited due to the complexity of both the mechanical components, stimulation systems, and human-machine interfaces. Assessment of system and participant performance is not reported in a standardized way. Future directions should address wearability through improvements in component technologies and user interfaces. Further, increased integration of the control action between NMES and robotic subsystems to reanimate the limb should be pursued. Standardized reporting of system performance and expanded clinical assessments of these systems are also needed. All of these advancements are critical to facilitate translation from lab to home.
Upon deformation, the generated surface charges induced by the piezoelectric material redistribute extracellular proteins and ions. Changes in streaming potential, aggregation of ionic species and ...adsorption of proteins, such as fibronectin, on the material surface can facilitate cell–material interaction. An influx of ions into the cells may also occur which can promote cell behavior/function on piezoelectric materials. Display omitted
The discovery of piezoelectricity, endogenous electric fields and transmembrane potentials in biological tissues raised the question whether or not electric fields play an important role in cell function. It has kindled research and the development of technologies in emulating biological electricity for tissue regeneration. Promising effects of electrical stimulation on cell growth and differentiation and tissue growth has led to interest in using piezoelectric scaffolds for tissue repair. Piezoelectric materials can generate electrical activity when deformed. Hence, an external source to apply electrical stimulation or implantation of electrodes is not needed. Various piezoelectric materials have been employed for different tissue repair applications, particularly in bone repair, where charges induced by mechanical stress can enhance bone formation; and in neural tissue engineering, in which electric pulses can stimulate neurite directional outgrowth to fill gaps in nervous tissue injuries. In this review, a summary of piezoelectricity in different biological tissues, mechanisms through which electrical stimulation may affect cellular response, and recent advances in the fabrication and application of piezoelectric scaffolds will be discussed.
The discovery of piezoelectricity, endogenous electric fields and transmembrane potentials in biological tissues has kindled research and the development of technologies using electrical stimulation for tissue regeneration. Piezoelectric materials generate electrical activity in response to deformations and allow for the delivery of an electrical stimulus without the need for an external power source. As a scaffold for tissue engineering, growing interest exists due to its potential of providing electrical stimulation to cells to promote tissue formation. In this review, we cover the discovery of piezoelectricity in biological tissues, its connection to streaming potentials, biological response to electrical stimulation and commonly used piezoelectric materials for tissue regeneration. This review summarizes their potential as a promising scaffold in the tissue engineering field.
Background
Several treatment options are available for stress urinary incontinence (SUI), including pelvic floor muscle training (PFMT), drug therapy and surgery. Problems exist such as adherence to ...PFMT regimens, side effects linked to drug therapy and the risks associated with surgery. We have evaluated an alternative treatment, electrical stimulation (ES) with non‐implanted devices, which aims to improve pelvic floor muscle function to reduce involuntary urine loss.
Objectives
To assess the effects of electrical stimulation with non‐implanted devices, alone or in combination with other treatment, for managing stress urinary incontinence or stress‐predominant mixed urinary incontinence in women. Among the outcomes examined were costs and cost‐effectiveness.
Search methods
We searched the Cochrane Incontinence Specialised Register, which contains trials identified from the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In‐Process, MEDLINE Epub Ahead of Print, CINAHL, ClinicalTrials.gov, WHO ICTRP and handsearches of journals and conference proceedings (searched 27 February 2017). We also searched the reference lists of relevant articles and undertook separate searches to identify studies examining economic data.
Selection criteria
We included randomised or quasi‐randomised controlled trials of ES with non‐implanted devices compared with any other treatment for SUI in women. Eligible trials included adult women with SUI or stress‐predominant mixed urinary incontinence (MUI). We excluded studies of women with urgency‐predominant MUI, urgency urinary incontinence only, or incontinence associated with a neurologic condition. We would have included economic evaluations had they been conducted alongside eligible trials.
Data collection and analysis
Two review authors independently screened search results, extracted data from eligible trials and assessed risk of bias, using the Cochrane 'Risk of bias' tool. We would have performed economic evaluations using the approach recommended by Cochrane Economic Methods.
Main results
We identified 56 eligible trials (3781 randomised participants). Eighteen trials did not report the primary outcomes of subjective cure, improvement of SUI or incontinence‐specific quality of life (QoL). The risk of bias was generally unclear, as most trials provided little detail when reporting their methods. We assessed 25% of the included trials as being at high risk of bias for a variety of reasons, including industry funding and baseline differences between groups. We did not identify any economic evaluations.
For subjective cure of SUI, we found moderate‐quality evidence that ES is probably better than no active treatment (risk ratio (RR) 2.31, 95% CI 1.06 to 5.02). We found a similar result for cure or improvement of SUI (RR 1.73, 95% CI 1.41 to 2.11), but the quality of evidence was lower. We are very uncertain if there is a difference between ES and sham treatment in terms of subjective cure because of the very low quality of evidence (RR 2.21, 95% CI 0.38 to 12.73). For subjective cure or improvement, ES may be better than sham treatment (RR 2.03, 95% CI 1.02 to 4.07). The effect estimate was 660/1000 women cured/improved with ES compared to 382/1000 with no active treatment (95% CI 538 to 805 women); and for sham treatment, 402/1000 women cured/improved with ES compared to 198/1000 with sham treatment (95% CI 202 to 805 women).
Low‐quality evidence suggests that there may be no difference in cure or improvement for ES versus PFMT (RR 0.85, 95% CI 0.70 to 1.03), PFMT plus ES versus PFMT alone (RR 1.10, 95% CI 0.95 to 1.28) or ES versus vaginal cones (RR 1.09, 95% CI 0.97 to 1.21).
Electrical stimulation probably improves incontinence‐specific QoL compared to no treatment (moderate quality evidence) but there may be little or no difference between electrical stimulation and PFMT (low quality evidence). It is uncertain whether adding electrical stimulation to PFMT makes any difference in terms of quality of life, compared with PFMT alone (very low quality evidence). There may be little or no difference between electrical stimulation and vaginal cones in improving incontinence‐specific QoL (low quality evidence). The impact of electrical stimulation on subjective cure/improvement and incontinence‐specific QoL, compared with vaginal cones, PFMT plus vaginal cones, or drugs therapy, is uncertain (very low quality evidence).
In terms of subjective cure/improvement and incontinence‐specific QoL, the available evidence comparing ES versus drug therapy or PFMT plus vaginal cones was very low quality and inconclusive. Similarly, comparisons of different types of ES to each other and of ES plus surgery to surgery are also inconclusive in terms of subjective cure/improvement and incontinence‐specific QoL (very low‐quality evidence).
Adverse effects were rare: in total nine of the women treated with ES in the trials reported an adverse effect. We identified insufficient evidence to compare the risk of adverse effects in women treated with ES compared to any other treatment. We were unable to identify any economic data.
Authors' conclusions
The current evidence base indicated that electrical stimulation is probably more effective than no active or sham treatment, but it is not possible to say whether ES is similar to PFMT or other active treatments in effectiveness or not. Overall, the quality of the evidence was too low to provide reliable results. Without sufficiently powered trials measuring clinically important outcomes, such as subjective assessment of urinary incontinence, we cannot draw robust conclusions about the overall effectiveness or cost‐effectiveness of electrical stimulation for stress urinary incontinence in women.
Background The growing use of transcranial electric and magnetic (EM) brain stimulation in basic research and in clinical applications necessitates a clear understanding of what constitutes the dose ...of EM stimulation and how it should be reported. Methods This paper provides fundamental definitions and principles for reporting of dose that encompass any transcranial EM brain stimulation protocol. Results The biologic effects of EM stimulation are mediated through an electromagnetic field injected (via electric stimulation) or induced (via magnetic stimulation) in the body. Therefore, transcranial EM stimulation dose ought to be defined by all parameters of the stimulation device that affect the electromagnetic field generated in the body, including the stimulation electrode or coil configuration parameters: shape, size, position, and electrical properties, as well as the electrode or coil current (or voltage) waveform parameters: pulse shape, amplitude, width, polarity, and repetition frequency; duration of and interval between bursts or trains of pulses; total number of pulses; and interval between stimulation sessions and total number of sessions. Knowledge of the electromagnetic field generated in the body may not be sufficient but is necessary to understand the biologic effects of EM stimulation. Conclusions We believe that reporting of EM stimulation dose should be guided by the principle of reproducibility: sufficient information about the stimulation parameters should be provided so that the dose can be replicated.
Summary
Objective
To demonstrate the safety and effectiveness of responsive stimulation at the seizure focus as an adjunctive therapy to reduce the frequency of seizures in adults with medically ...intractable partial onset seizures arising from one or two seizure foci.
Methods
Randomized multicenter double‐blinded controlled trial of responsive focal cortical stimulation (RNS System). Subjects with medically intractable partial onset seizures from one or two foci were implanted, and 1 month postimplant were randomized 1:1 to active or sham stimulation. After the fifth postimplant month, all subjects received responsive stimulation in an open label period (OLP) to complete 2 years of postimplant follow‐up.
Results
All 191 subjects were randomized. The percent change in seizures at the end of the blinded period was −37.9% in the active and −17.3% in the sham stimulation group (p = 0.012, Generalized Estimating Equations). The median percent reduction in seizures in the OLP was 44% at 1 year and 53% at 2 years, which represents a progressive and significant improvement with time (p < 0.0001). The serious adverse event rate was not different between subjects receiving active and sham stimulation. Adverse events were consistent with the known risks of an implanted medical device, seizures, and of other epilepsy treatments. There were no adverse effects on neuropsychological function or mood.
Significance
Responsive stimulation to the seizure focus reduced the frequency of partial‐onset seizures acutely, showed improving seizure reduction over time, was well tolerated, and was acceptably safe. The RNS System provides an additional treatment option for patients with medically intractable partial‐onset seizures.
This study aims to compare the effectiveness of conventional dysphagia therapy (CDT), neuromuscular electrical stimulation (NMES), and transcranial direct current stimulation (tDCS) in the treatment ...of post-stroke dysphagia. A single-blind randomized controlled trial was conducted with 40 acute stroke patients – 18 females and 22 males with a mean age of 65.8 ± 11.9. The subjects were grouped into 4, with 10 individuals in each. The procedures administered to groups were as follows: the first group, sham tDCS and sham NMES; the second group, tDCS and sham NMES; the third group, NMES and sham tDCS; and the fourth group, all therapy procedures. CDT was applied to all groups either as a standalone procedure or combined with one or two of the instrumental techniques. Gugging Swallowing Screen (GUSS) and Videofluoroscopic Swallowing Study (VFSS) were employed to determine the severity of dysphagia and the effectiveness of treatment modalities. Additionally, the Penetration Aspiration Scale (PAS), Functional Oral Intake Scale (FOIS), and Dysphagia Severity Rating Scale (DSRS) were administered to interpret VFSS data. Pre- and post-treatment comparisons of all groups have revealed a statistically significant difference for all parameters except for the PAS scores at International Dysphagia Diet Standardization Initiative (IDDSI)-Level 4 consistencies. However, the differences between pre- and post-treatment scores of the fourth group across all parameters were significant – GUSS (
p
= 0.005), FOIS (
p
= 0.004), DSRS (
p
= 0.005), PAS IDDSI-4 (
p
= 0.027), PAS IDDSI-0 (
p
= 0.004). Inter-group comparisons, on the other hand, pointed out that the difference between pre- and post-treatment GUSS, FOIS, DSRS, and PAS scores at IDDSI Level-0 consistencies was statistically significant for all groups – GUSS (
p
= 0,009), FOIS (
p
= 0,004), DSRS (
p
= 0,002), PAS IDDSI-0 (
p
= 0,049). Closer examination of treatment groups indicated that the tDCS + CDT group, the NMES + CDT group, and the group that underwent the combination of three modalities made better progress than the one that was treated with only CDT. Though not statistically significant, the NMES + CDT group achieved better improvement than the tDCS + CDT group. This study has yielded that the group in which NMES, tDCS, and CDT were applied in combination has achieved better results than all the other groups. All treatment modalities applied to accelerate the general recovery process in acute stroke patients with dysphagia were found to be effective for the treatment of post-stroke swallowing disorders. The use of instrumental treatments such as NMES and tDCS enhanced the effectiveness of the treatment and provided more significant progress. Furthermore, combining treatment modalities such as NMES and tDCS was more effective when compared to using only conventional therapy. As a result, the most effective treatment outcomes were obtained by the group receiving CDT, NMES, and tDCS in combination. Therefore, the use of combined approaches has been recommended in appropriate patients; yet the provisional results should be tested in randomized trials with more participants.
Sacral neuromodulation (SNM) (sacral nerve stimulation SNS) has become an established therapy for functional disorders of the pelvic organs. Despite its overall success, the therapy fails in a ...proportion of patients. This may be partially due to inadequate electrode placement with suboptimal coupling of the electrode and nerve. Based on these assumptions the technique of sacral spinal neuromodulation has been redefined. All descriptions relate to the only currently available system licensed for all pelvic indications (Medtronic Interstim
).
An international multidisciplinary working party of ten individuals highly experienced in performing SNM convened two meetings (including live operating) to standardize the implant procedure. This report addresses the main steps to optimal electrode lead placement in temporal sequence.
Key elements of the electrode placement are radiological marking, the use of a curved stylet, the entry of the electrode into the sacral foramen and its progression through the foramen, its placement guided by a combination of a typical appearance in fluoroscopy and achieving specific motor/sensory responses with stimulation. The report describes quadripolar electrode placement and then either insertion of a connecting percutaneous extension lead or permanent implantation of the programmable device.
Standardization of electrode placement may ensure close electrode proximity to the target nerve providing a higher likelihood for optimal effect with less energy consumption (better battery longevity), more programming options with more electrode contacts close to the nerve and reduced likelihood of side-effects. The potentially better clinical outcome needs to be demonstrated.
High-definition transcranial direct current stimulation (HD-tDCS) has recently been developed as a noninvasive brain stimulation approach that increases the accuracy of current delivery to the brain ...by using arrays of smaller "high-definition" electrodes, instead of the larger pad-electrodes of conventional tDCS. Targeting is achieved by energizing electrodes placed in predetermined configurations. One of these is the 4x1-ring configuration. In this approach, a center ring electrode (anode or cathode) overlying the target cortical region is surrounded by four return electrodes, which help circumscribe the area of stimulation. Delivery of 4x1-ring HD-tDCS is capable of inducing significant neurophysiological and clinical effects in both healthy subjects and patients. Furthermore, its tolerability is supported by studies using intensities as high as 2.0 milliamperes for up to twenty minutes. Even though 4x1 HD-tDCS is simple to perform, correct electrode positioning is important in order to accurately stimulate target cortical regions and exert its neuromodulatory effects. The use of electrodes and hardware that have specifically been tested for HD-tDCS is critical for safety and tolerability. Given that most published studies on 4x1 HD-tDCS have targeted the primary motor cortex (M1), particularly for pain-related outcomes, the purpose of this article is to systematically describe its use for M1 stimulation, as well as the considerations to be taken for safe and effective stimulation. However, the methods outlined here can be adapted for other HD-tDCS configurations and cortical targets.
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