Trans-Spinal Direct Current Stimulation in Neurological Disorders: A systematic review.

BACKGROUND AND PURPOSE: Trans-spinal direct current stimulation (tsDCS) is a noninvasive stimulation technique that applies direct current stimulation over spinal levels. However, the effectiveness and feasibility of this stimulation are still unclear. This systematic review summarizes the effectiveness of tsDCS in clinical and neurophysiological outcomes in neurological patients, as well as its feasibility and safety. METHODS: The search was conducted using the following databases: PEDro, Scopus, Web of Science, CINAHL, SPORTDiscus, and PubMed. The inclusion criteria were: Participants : people with central nervous system diseases; Interventions : tsDCS alone or in combination with locomotion training; Comparators : sham tsDCS, transcranial direct current stimulation, or locomotion training; Outcomes : clinical and neurophysiological measures; and Studies : randomized clinical trials. RESULTS: Eight studies with a total of 143 subjects were included. Anodal tsDCS led to a reduction in hypertonia, neuropathic pain intensity, and balance deficits in people with hereditary spastic paraplegia, multiple sclerosis, and primary orthostatic tremor, respectively. In contrast, cathodal tsDCS only had positive effects on balance and tremor in people with primary orthostatic tremor. No severe adverse effects were reported during and after anodal or cathodal tsDCS. DISCUSSION AND CONCLUSIONS: Although certain studies have found an effect of anodal tsDCS on specific clinical outcomes in people with central nervous system diseases, its effectiveness cannot be established since these findings have not been replicated and the results were heterogeneous. This stimulation was feasible and safe to apply. Further studies are needed to replicate the obtained results of tsDCS when applied in populations with neurological diseases.

Factors Associated With Fatigue in People With Spinal Cord Injury: A Systematic Review and Meta-analysis.

OBJECTIVE: To investigate the association between fatigue and clinical and demographic variables in people with spinal cord injury (SCI). DATA SOURCES: Five databases (MEDLINE, Physiotherapy Evidence Database, Cochrane, Google Scholar, Cumulative Index to Nursing and Allied Health) were searched up to November 2021. STUDY SELECTION: Observational studies that reported the association between fatigue and clinical and demographic variables in English or Spanish were eligible. Reviews, qualitative research studies, and nonoriginal articles were excluded. Twenty-three of the 782 identified studies met the inclusion criteria for the meta-analysis. DATA EXTRACTION: Two researchers independently extracted the data. The strength of the association between each factor and fatigue was determined by the effect size. When the results of the effect size were expressed with different statistics, the correlation coefficient was the preferred estimation. The risk of bias was assessed using the Appraisal Tool for Cross-Sectional Studies and the Newcastle-Ottawa Scale. DATA SUMMARY: A pooled analysis of the associations between fatigue and 17 factors was performed. A direct association was found between fatigue and 9 factors (sorted by effect size): anxiety (r=0.57; 95% CI, 0.29-0.75), stress (r=0.54; 95% confidence interval [CI], 0.26-0.74), depression (r=0.47; 95% CI, 0.44-0.50), pain (r=0.34; 95% CI, 0.16-0.50), analgesic medication (r=0.32; 95% CI, 0.28-0.36), assistive devices (r=0.23; 95% CI, 0.17-0.29), lesion level (r=0.15; 95% CI, 0.07-0.23), incomplete SCI (r=0.13; 95% CI, 0.05-0.22), and medication (r=0.12; 95% CI, 0.01-0.23). An inverse association was found with 3 factors (sorted by effect size): self-efficacy (r=-0.63; 95% CI, -0.81 to -0.35), participation (r=-0.32; 95% CI, -0.58 to -0.001), and physical activity (r=-0.17; 95% CI, -0.28 to -0.05). No association was found with age, sex, educational level, time since injury, and spasticity. CONCLUSIONS: Several factors were associated with fatigue in people with SCI, with those related to mental health showing the strongest associations. These results should be interpreted with caution because of the high heterogeneity observed in some factors.

Effectiveness of transcranial direct current stimulation on balance and gait in patients with multiple sclerosis: systematic review and meta-analysis of randomized clinical trials.

BACKGROUND: Motor impairments are very common in neurological diseases such as multiple sclerosis. Noninvasive brain stimulation could influence the motor function of patients. OBJECTIVE: The aim of this meta-analysis was to evaluate the effectiveness of transcranial direct current stimulation (tDCS) on balance and gait ability in patients with multiple sclerosis. Additionally, a secondary aim was to compare the influence of the stimulation location of tDCS on current effectiveness. METHODS: A search was conducted for randomized controlled trials published up to May 2023 comparing the application of tDCS versus a sham or control group. The primary outcome variables were balance and gait ability. RESULTS: Eleven studies were included in the qualitative analysis, and ten were included in the quantitative analysis, which included 230 patients with multiple sclerosis. The average effect of tDCS on gait functionality was superior to that of the control group (SMD = -0.71; 95% CI, -1.05 to -0.37). However, the overall results of the tDCS vs. sham effect on static balance did not show significant differences between groups (MD = 1.26, 95% CI, -1.31 to 3.82). No significant differences were found when different locations of tDCS were compared. CONCLUSIONS: These results reveal that tDCS is an effective treatment for improving gait ability with a low quality of evidence. However, the application of tDCS has no effect on static balance in patients with multiple sclerosis with very low quality of evidence. Similarly, there seems to be no difference regarding the stimulation area with tDCS.

Percutaneous Versus Transcutaneous Electrical Nerve Stimulation for the Treatment of Musculoskeletal Pain. A Systematic Review and Meta-Analysis.

BACKGROUND: The justification for this review is the need for high-quality evidence to assist in the decision-making process when applying percutaneous electrical nerve stimulation (PENS) or transcutaneous electrical nerve stimulation (TENS) in a clinical setting. The main aim was to determine if the use of PENS is more effective and should be recommended when compared to TENS for the reduction of musculoskeletal pain intensity. METHODS: A search for randomized controlled trials (RCTs) was performed. Studies published until 31/12/2020, comparing the effectiveness of PENS and TENS, were considered. The main outcome was pain assessed with a visual analog scale or numerical pain rating scale. RESULTS: Nine RCTs were included in the qualitative analysis, with seven of them in the quantitative analysis (n = 527). The overall effect of PENS on pain was statistically but not clinically superior to TENS (mean difference [MD]=-1.0 cm; 95% confidence interval [CI]: -1.5 to -0.4) with a high level of heterogeneity (I2=76%, P > .01). When only studies with a lower risk of bias (n = 3) were analyzed, the heterogeneity decreased to I = 0% (P = .06) and no difference was observed between TENS and PENS (MD=-0.81 cm; 95% CI:-1.6 to 0.02) with a moderate recommendation level according to GRADE. There were no data concerning adverse effects. CONCLUSIONS: There is low-quality of evidence for more pain intensity reduction with PENS, but the difference was not clinically significant. However, when only studies with low risk of bias are meta-analyzed, there is a moderate quality of evidence that there is no difference when TENS or PENS is applied for pain intensity.

Effectiveness of Transcranial Direct Current Stimulation Combined With Exercising in People With Fibromyalgia: A Randomized Sham-Controlled Clinical Trial.

OBJECTIVE: To evaluate the effectiveness of transcranial direct current stimulation (tDCS) combined with exercising in people with fibromyalgia. DESIGN: Randomized, triple-blind, sham-controlled, clinical trial. SETTING: Primary health care center. PARTICIPANTS: A total of 120 volunteer participants (N=120) between 18 and 65 years old and diagnosed with fibromyalgia. Four participants dropped out of the study for causes unrelated to the intervention. INTERVENTION: Participants were randomized into 3 groups (active tDCS+exercising, sham tDCS+exercising, no-intervention control). The intervention was delivered in 5 sessions over 2 weeks. MAIN OUTCOME MEASURES: Pain intensity and referred pain area after suprathreshold pressure stimulation. RESULTS: Pain intensity further decreased in the active tDCS group vs control (mean, -14.43; 95% confidence interval, -25.27 to -3.58) at post intervention, unlike the sham tDCS group. Both tDCS groups did not achieve greater reductions in referred pain vs control. In the active tDCS group, health status (mean, -14.80; 95% confidence interval, -23.10 to -6.50) and pain catastrophizing (mean, -6.68, 95% confidence interval, -11.62 to -1.73) improved at post intervention, and so did health status (mean, -8.81; 95% confidence interval, -17.11 to -0.51), pain catastrophizing (mean, -7.00; 95% confidence interval, -12.13 to -1.87), and depression (mean, -3.52; 95% confidence interval, -6.86 to -0.19) after 1 month. In the sham tDCS group, improvements were recorded in health status (mean, -13.21; 95% confidence interval, -21.52 to -4.91) and depression (mean, -3.35; 95% confidence interval, -6.35 to -0.35) at post intervention and in health status (mean, -8.77; 95% confidence interval, -17.06 to -0.47), pain catastrophizing (mean, -5.68; 95% confidence interval, -10.80 to -0.55), and depression (mean, -3.98; 95% confidence interval, -7.31 to -0.64) after 1 month. No intergroup differences were observed between active and sham tDCS. CONCLUSIONS: Active and sham tDCS improved health status, pain catastrophizing, and depression vs control, but pain intensity decreased only in the active tDCS group.

Intensive complex physical therapy combined with intermittent pneumatic compression versus Kinesio taping for treating breast cancer-related lymphedema of the upper limb: A randomised cross-over clinical trial.

OBJECTIVE: The objective of this study is to compare the effectiveness of complex physical therapy combined with intermittent pneumatic compression (CPT + IPC) versus Kinesio taping (KT) for breast cancer-related lymphedema. METHODS: A cross-over clinical trial was conducted in 43 women with lymphedema. All participants received two interventions: CPT + IPC and KT, both lasting 3 weeks and a washout period. The main outcome variable was the relative volume change (RVC). The secondary variables were Satisfaction Questionnaire about Textile Therapeutic Devices used for Breast Cancer-Related Lymphedema, Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, motion range of upper limb and lymphedema-related symptoms. RESULTS: The RVC reduction was greater with CPT + IPC (-2.2%, SD = 4.7) versus KT (-0.9%, SD = 1.7) (P = 0.002). KT was more satisfactory than multilayer bandaging (8.9 points difference, P < 0.001) and improved DASH score more than CPT + IPC (14.3 points difference, P = 0.002). Regarding motion ranges, only shoulder movements showed significant improvement with CPT + IPC compared with KT (differences between 5.6° and 11.4°). Of the symptoms assessed, only pain reduction showed a significant improvement with KT versus CPT + IPC (0.5 points, P = 0.035). CONCLUSIONS: CPT + IPC achieved higher RVC and greater improvement in th shoulder motion range than KT. Conversely, KT was more satisfactory than multilayer bandaging, obtained better DASH scores and relieved pain more than CPT + IPC. CLINICAL REGISTRATION: ClinicalTrial registration number: NCT03051750 (date of registration 14 February 2017).

Capacitive resistive monopolar radiofrequency at 448 kHz plus exercising versus exercising alone for subacromial pain: A sham-controlled randomized clinical trial.

OBJECTIVE: To investigate the effectiveness of thermal and sub-thermal capacitive-resistive monopolar radiofrequency at 448 kHz plus exercising compared to sham radiofrequency plus exercising on pain, functionality, and quality of life in patients with subacromial pain. DESIGN: Randomized, controlled, parallel, double-blind, three-arm clinical trial. SETTING: Hospital and Primary Care. SUBJECTS: Eighty-one participants with subacromial pain in three intervention groups. INTERVENTIONS: Three interventions with capacitive-resistive radiofrequency (thermal, sub-thermal, and sham) over 9 sessions (3 per week) plus an exercising protocol identical for all groups over 15 sessions (5 per week). OUTCOME MEASURES: Visual analogue scale and pressure pain threshold for pain, Shoulder Pain and Disability Index and Quick-Disabilities of the Arm, Shoulder and Hand for functionality, and quality of life via the European Quality of Life-Five Dimensions were assessed at baseline, immediately posttreatment, and 1 month and 3 months post-intervention. RESULTS: No between-group differences were found in the pain visual analogue scale (F = 1.0; P = 0.37), Shoulder Pain and Disability Index (F = 1.0; P = 0.36), European Quality of Life-Five Dimensions (F = 0.76; P = 0.47), and pressure pain (F = 0.14; P = 0.86) outcomes, with a statistical power < 0.30 for all comparisons. Between-group differences were found in the Quick-Disabilities of the Arm, Shoulder and Hand (F = 3.4; P < 0.038), with an improvement of -14.1 points (confidence interval at 95% (95% CI) -28.1 to -0.1) in the thermal versus the sham group at 1 month follow-up. The mobility dimension of European Quality of Life-Five Dimensions improved in a greater proportion of participants in the thermal group (22.2% thermal, 7.4% sub-thermal, and 0.0% sham; P = 0.02). CONCLUSION: Adding thermal radiofrequency to exercising can further improve slightly functionality and mobility in people with subacromial pain in the short term, but not pain perception. Future studies with larger sample sizes are warranted to increase statistical power.

Electrical microcurrent stimulation therapy for wound healing: A meta-analysis of randomized clinical trials.

BACKGROUND: Electrical microcurrent therapy (EMT) consists of the application of low intensity (µA) currents that are similar to endogenous electric fields generated during wound healing. AIMS: To examine the effectiveness and safety of EMT for improving wound healing and pain in people with acute or chronic wounds. METHOD: Randomized clinical trials (RCTs) assessing the effectiveness of EMT in wound healing published up to August 1st, 2020 were included. The main outcomes were wound surface area, healing time, and number of wounds healed. Secondary outcomes were pain perception and adverse events. A quantitative analysis was conducted using the inverse variance and Mantel-Haenszel methods. RESULTS: Eight RCTs were included in the qualitative summary and seven in the quantitative analysis (n = 337 participants). EMT plus standard wound care (SWC) produced a greater decrease in wound surface [mean difference (MD) = -8.3 cm2; CI 95%: -10.5 to -6.0] and healing time (MD = -7.0 days; CI 95%: -11.9 to -2.1) that SWC alone, showing moderate and low certainty in the evidence, respectively. However, no differences were observed in the number of healed wounds [risk ratio = 2.0; CI 95%: 0.5 to 9.1], with very low quality of evidence. EMT decreased perceived pain (MD = -1.4; CI 95%: -2.7 to -0.2), but no differences in adverse effects were noted between groups (risk difference = 0.05; CI 95%: -0.06 to 0.17). CONCLUSIONS: EMT is an effective, safe treatment for improving wound area, healing time, and pain. Further clinical trials that include detailed intervention parameters and protocols should be designed to lower the risk of bias.

Efficacy of Anodal Suboccipital Direct Current Stimulation for Endogenous Pain Modulation and Tonic Thermal Pain Control in Healthy Participants: A Randomized Controlled Clinical Trial.

OBJECTIVE: The aim of this study was to assess whether anodal DCS applied to the suboccipital (SO) target area could potentiate antinociception assessed primarily with conditioned pain modulation of tonic thermal test stimuli. DESIGN: Randomized double-blinded control trial. SETTING: Rehabilitation hospital. SUBJECTS: Healthy participants. METHODS: Forty healthy participants were randomized to receive either SO-DCS or M1-DCS. The 20-minute 1.5 mA anodal or sham DCS intervention were applied to each participant in randomized order during two test sessions. The primary outcome measure included heterotopic cold-pressor conditioned pain modulation (CPM) of tonic heat pain. Secondary measures included pressure pain threshold and tonic thermal pain intensity. RESULTS: Heterotopic CPM of tonic heat pain intensity was unaffected by either SO-DCS or active M1, including the secondary measures of pressure pain threshold and tonic thermal pain intensity. Although low-power non-significant interactions were identified for DCS intervention (active versus sham) and time (before and after), a significant within-group inhibition of tonic cold pain was identified following SO-DCS (P = .011, mean [SD]: -0.76 ± 0.88 points) and M1-DCS (P < .002: -0.84 ± 0.82 points), without a significant change following sham DCS. CONCLUSIONS: Although heterotopic CPM was not facilitated with either SO-DCS or M1-DCS, a general significant inhibition of tonic cold pain intensity was demonstrated following both interventions. The general effects of active DCS compared to sham on tonic cold pain-irrespective of the M1 or SO target-need to be confirmed using standard quantitative sensory testing.

Correlation between three assessment pain tools in subacromial pain syndrome.

OBJECTIVE: To compare the correlation of Visual Analog Scale with pain subsections of Shoulder Pain and Disability Index and Constant-Murley Score in subacromial pain syndrome patients. DESIGN: Single cross-sectional analysis. SETTING: Hospital Rehabilitation Department. METHODS: The assessment tools were applied at baseline. Correlations between Visual Analog Scale, Shoulder Pain and Disability Index and Constant-Murley Score pain subsections were assessed by Pearson correlation coefficient. Linear regression models were calculated between scales. Statistical significance was set at two-sided p < 0.05. RESULTS: Forty-three patients were included. Pearson's correlation between assessments was for Visual Analog Scale-Shoulder Pain Disability Index-pain (r = 0.61, p < 0.001) and for Visual Analog Scale-Constant Murley Score-pain were (r = -0.74, p < 0.001). Visual Analog Scale-Shoulder Pain and Disability Index-pain determination coefficient was r2 = 0.37 and r2 = 0.54 for Visual Analog Scale-Constant-Murley Score-pain. CONCLUSIONS: Visual Analog Scale showed better correlation with Constant Murley Score-pain than with Shoulder Pain and Disability Index-pain in subacromial pain syndrome patients.

Transcranial direct current stimulation combined with robotic therapy for upper and lower limb function after stroke: a systematic review and meta-analysis of randomized control trials.

BACKGROUND: Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation method able to modulate neuronal activity after stroke. The aim of this systematic review was to determine if tDCS combined with robotic therapy (RT) improves limb function after stroke when compared to RT alone. METHODS: A search for randomized controlled trials (RCTs) published prior to July 15, 2021 was performed. The main outcome was function assessed with the Fugl-Meyer motor assessment for upper extremities (FM/ue) and 10-m walking test (10MWT) for the lower limbs. As secondary outcomes, strength was assessed with the Motricity Index (MI) or Medical Research Council scale (MRC), spasticity with the modified Ashworth scale (MAS), functional independence with the Barthel Index (BI), and kinematic parameters. RESULTS: Ten studies were included for analysis (n = 368 enrolled participants). The results showed a non-significant effect for tDCS combined with RT to improve upper limb function [standardized mean difference (SMD) = - 0.12; 95% confidence interval (CI): - 0.35-0.11)]. However, a positive effect of the combined therapy was observed in the lower limb function (SMD = 0.48; 95% CI: - 0.15-1.12). Significant results favouring tDCS combined with RT were not found in strength (SMD = - 0.15; 95% CI: - 0.4-0.1), spasticity [mean difference (MD) = - 0.15; 95% CI: - 0.8-0.5)], functional independence (MD = 2.5; 95% CI: - 1.9-6.9) or velocity of movement (SMD = 0.06; 95% CI: - 0.3-0.5) with a "moderate" or "low" recommendation level according to the GRADE guidelines. CONCLUSIONS: Current findings suggest that tDCS combined with RT does not improve upper limb function, strength, spasticity, functional independence or velocity of movement after stroke. However, tDCS may enhance the effects of RT alone for lower limb function. tDCS parameters and the stage or type of stroke injury could be crucial factors that determine the effectiveness of this therapy.

20-kHz alternating current stimulation: effects on motor and somatosensory thresholds.

BACKGROUND: High frequency alternating current (HFAC) stimulation have been shown to produce a peripheral nerve conduction block. Currently, all the studies applying HFAC stimulation in clinical studies, have employed frequencies below 10 kHz. The main aim of this work was to investigate the neuromodulatory effect of transcutaneous 20 kHz stimulation on somatosensory and pain thresholds, and maximal handgrip strength. METHODS: A randomized, crossover, single-blinded, placebo-controlled trial was conducted following recruitment of fourteen healthy volunteers. Transcutaneous stimulation at 20 kHz and sham stimulation were applied over the ulnar and median nerves of fourteen healthy volunteers for 20 min. Maximal handgrip strength (MHS), mechanical detection threshold (MDT) and pressure pain threshold (PPT) were registered prior to, during (15 min), immediately after the end (20 min), and 10 min following stimulation. RESULTS: The 20 kHz stimulation showed a lower MHS during the stimulation at the 15 min (30.1 kgs SE 2.8) and at 20 min (31.8 kgs, SE 2.8) when compared to sham stimulation (35.1 kgs, SE 3.4; p < 0.001 and 34.2 kgs, SE 3.4; p = 0.03, respectively). The 20 kHz stimulation resulted in a slight increase in MDT at 15 min (0.25 mN; 0.25-2.00) when compared to the sham stimulation (0.25 mN; 0.25-0.25; p = 0.02), and no effects were showed for PPT. CONCLUSIONS: High-frequency stimulation at 20 kHz suggests a partial block of nerve activity. Studies in subjects with neurological disorders characterized by nerve hyperactivity are needed to confirm the clinical impact of this non-invasive electrical stimulation technique. TRIAL REGISTRATION: NCT, NCT02837458. Registered on 12 April 2017.

Kinesio taping versus compression garments for treating breast cancer-related lymphedema: a randomized, cross-over, controlled trial.

OBJECTIVE: To determine the effectiveness of Kinesio taping compared to compression garments during maintenance phase of complex decongestive therapy for breast cancer-related lymphedema. DESIGN: Randomized, cross-over, controlled trial. SETTING: Outpatient tertiary-level hospital rehabilitation setting. SUBJECTS: Randomized sample of 30 women with breast cancer-related lymphedema. INTERVENTIONS: Participants received two interventions, Kinesio taping and compression garment, both lasting four weeks, whose order was randomized by blocks. A four-week washout period was established prior to the interventions and between them. MEASUREMENTS: The main outcome was the lymphedema Relative Volume Change. Secondary outcomes were range of motion of arm joints, self-perception of comfort, and lymphedema-related symptoms (pain, tightness, heaviness, and hardness). RESULTS: The decrease in the Relative Volume Change was greater in the Kinesio taping intervention (-5.7%, SD = 2.0) compared to that observed using compression garments (-3.4%, SD = 2.9) (P < 0.001). The range of motion of five upper-limb movements increased after applying taping (between 5.8° and 16.7°) (P < 0.05), but not after compression (P > 0.05). In addition, taping was perceived as more comfortable by patients (between 2.4 and 3 points better than compression in four questions with a 5-point scale (P < 0.001)) and further reduced lymphedema-related symptoms compared to compression (between 0.96 and 1.40 points better in four questions with a 6-point scale (P < 0.05)). CONCLUSION: Kinesio taping was more effective than compression garments for reducing the lymphedema volume, with less severe lymphedema-related symptoms, better improvement of upper-limb mobility, and more comfort.

Efficacy of high-intensity laser therapy in subacromial impingement syndrome: a three-month follow-up controlled clinical trial.

OBJECTIVES: To evaluate the effectiveness of high-intensity laser therapy on shoulder pain and function in subacromial impingement syndrome. DESIGN: Clinical controlled trial with alternate allocation. SETTING: Hospital Department of Rehabilitation. SUBJECTS: A total of 46 participants with subacromial impingement syndrome. INTERVENTION: Participants were sequence allocated to an intervention group (high-intensity laser therapy + exercise therapy) and control group (sham-laser + exercise therapy) and received 15 sessions (five days a week during three weeks). MAIN MEASURES: Patiens were evaluated at baseline, after 15 sessions, and at one month and at three months after completing the intervention. The main outcome variables were pain and functionality as measured by visual analogue scale; pressure pain threshold; Shoulder Pain and Disability Index; Constant-Murley Score; and QuickDASH. Secondary outcomes were number of sessions at discharge and drug use. RESULTS: A total of 21 patients in high-intensity laser therapy group (56.7 ± 8.9 years) and 22 patients in sham-laser group (61.3 ± 8.9 years) concluded the study. Visual analogue scale (cm) at baseline, one-month, and three-months were 6.2 ± 0.5, 3 ± 2.6, and 2.6 ± 2.4 for the control group and 5.4 ± 1.5, 3.6 ± 1.3, and 1.8 ± 1.7 for experimental group, respectively. Shoulder Pain and Disability Index (points) at baseline, one-month, and three-monts were 51.8 ± 16.1, 16.3 ± 16.1, and 13.6 ± 17.1 in the control group and 41.8 ± 20.6, 20.5 ± 19.7, 11 ± 14.5 in experimental group, respectively. No differences were found between groups ( P > 0.05). CONCLUSION: The effect of high-intensity laser therapy plus exercise is not higher than exercise alone to reduce pain and improve functionality in patients with subacromial syndrome.

Combining transcranial direct-current stimulation with gait training in patients with neurological disorders: a systematic review.

BACKGROUND: Transcranial direct-current stimulation (tDCS) is an easy-to-apply, cheap, and safe technique capable of affecting cortical brain activity. However, its effectiveness has not been proven for many clinical applications. OBJECTIVE: The aim of this systematic review was to determine whether the effect of different strategies for gait training in patients with neurological disorders can be enhanced by the combined application of tDCS compared to sham stimulation. Additionally, we attempted to record and analyze tDCS parameters to optimize its efficacy. METHODS: A search in Pubmed, PEDro, and Cochrane databases was performed to find randomized clinical trials that combined tDCS with gait training. A chronological filter from 2010 to 2018 was applied and only studies with variables that quantified the gait function were included. RESULTS: A total of 274 studies were found, of which 25 met the inclusion criteria. Of them, 17 were rejected based on exclusion criteria. Finally, 8 trials were evaluated that included 91 subjects with stroke, 57 suffering from Parkinson's disease, and 39 with spinal cord injury. Four of the eight assessed studies did not report improved outcomes for any of its variables compared to the placebo treatment. CONCLUSIONS: There are no conclusive results that confirm that tDCS can enhance the effect of the different strategies for gait training. Further research for specific pathologies, with larger sample sizes and adequate follow-up periods, are required to optimize the existing protocols for applying tDCS.

[Analgesic effects of transcutaneous electrical nerve stimulation (TENS) in patients with fibromyalgia: A systematic review]. / Efectos analgésicos de la estimulación eléctrica nerviosa transcutánea en pacientes con fibromialgia: una revisión sistemática.

OBJECTIVE: To determine whether transcutaneous electrical nerve stimulation (TENS) has an analgesic effect greater than placebo or other treatments in patients with fibromyalgia. Furthermore, it was intended to analyze the optimal application parameters to achieve a greater reduction of pain. DESIGN: A systematic review. DATA SOURCE: Randomized clinical trials on the effect of TENS on fibromyalgia in the databases Pubmed, Cochrane and PEDro until November 2016. SELECTION OF STUDIES: 8 studies out of a total of 62 were selected. Controlled clinical trials in which TENS was applied in patients with fibromyalgia were included. DATA EXTRACTION: Pain was analyzed as the main variable, although other variables such as fatigue, quality of life and impact, range of motion and depression were also included. RESULTS: 6 out of 8 studies obtained a significant decrease of pain. In 2 studies, TENS was applied as complementary treatment to therapeutic exercise with results evidencing a decrease in pain. The rest of the variables studied presented a great variability and conclusive results could not be established. CONCLUSIONS: Treatment with TENS is effective for reducing pain in people with fibromyalgia. In addition, the inclusion of TENS in therapeutic exercise programs seems to have a greater effect than practicing therapeutic exercise in isolation. However, no efficacy has been demonstrated in other variables different to pain. Further studies are needed to investigate the optimization of the parameters of the TENS and a greater consensus among the variables used.

Effect of high-frequency alternating current transcutaneous stimulation over muscle strength: a controlled pilot study.

BACKGROUND: High-frequency alternating currents of greater than 1 kHz applied on peripheral nerves has been used in animal studies to produce a motor nerve block. It has been evidenced that frequencies higher than 5 kHz are necessary to produce a complete peripheral nerve block in primates, whose nerve thickness is more similar to humans. The aim of the study was to determine the effect on muscle strength after the application of a high-frequency stimulation at 5 and 10 kHz compared to sham stimulation in healthy volunteers. FINDINGS: Transcutaneous stimulation at 5 kHz, 10 kHz and sham stimulation were applied to eleven healthy volunteers over the ulnar and median nerves for 20 min. Maximal handgrip strength was measured before, during, immediately after the intervention, and 10 min after the end of intervention. The 10 kHz stimulation showed a lower handgrip strength during the intervention (28.1 N, SEM 3.9) when compared to 5 kHz (31.1 N, SEM 3.6; p < 0.001) and to sham stimulation (33.7 N, SEM 3.9; p < 0.001). Furthermore, only stimulation at 10 kHz decreased handgrip strength when compared to baseline. CONCLUSIONS: These findings suggest high-frequency stimulation has an inhibitory effect over muscle strength. Future studies are required in patients that are characterized by motor hyperactive such as spasticity or tremors. CLINICAL TRIAL REGISTRATION: NCT, NCT03169049 . Registered on 30 May 2017.

Posterior tibial nerve stimulation in the treatment of fecal incontinence: a systematic review.

Fecal incontinence severely impacts on quality of life, causing stigmatization and social exclusion. Posterior tibial nerve stimulation (PTNS) is one technique used for treatment. This systematic review aims to assess the effectiveness of PTNS for the treatment of fecal incontinence. A literature review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) declaration. Pubmed, Scopus, Web of Knowledge and PEDro databases were searched for both randomized clinical trials and cases series. The outcome variables were treatment effectiveness, severity of incontinence and quality of life; all were measured in the short, mid and long-term after performing both percutaneous and transcutaneous PTNS. Twenty-three studies met the selection criteria. Two clinical trials found significant differences in treatment effectiveness compared to the placebo response. Fifteen cases series observed significant differences in terms of effectiveness, severity and quality of life. All clinical trials achieved a reduction in the number of incontinence episodes and an increase in the deferral time for defecation. Optimal results were achieved by interventions consisting of one or two weekly sessions of a 30-60 minutes duration and the use of pulse widths of 200 µs and frequencies of 10-20 Hz. Percutaneous stimulation did not demonstrate better results compared to transcutaneous application. PTNS is an effective technique for the treatment of fecal incontinence, although long-term interventions are required in order to prolong its effects in the long-term.

Effect of Unmodulated 5-kHz Alternating Currents Versus Transcutaneous Electrical Nerve Stimulation on Mechanical and Thermal Pain, Tactile Threshold, and Peripheral Nerve Conduction: A Double-Blind, Placebo-Controlled Crossover Trial.

OBJECTIVE: To investigate the effect of unmodulated 5-kHz alternating current on mechanical pain threshold (MPT), heat pain threshold (HPT), tactile threshold (TT), and peripheral nerve conduction (PNC) compared with transcutaneous electrical nerve stimulation (TENS) and sham stimulation. SETTING: National referral center. DESIGN: Randomized, double-blind, placebo-controlled crossover trial. PARTICIPANTS: Healthy volunteers (N=38). No dropouts or adverse events were reported. INTERVENTION: TENS, unmodulated 5-kHz currents, and sham stimulation were applied on the radial nerve for 20 minutes with a 24-hour washout period between them and concealed intervention allocation. MAIN OUTCOME MEASURES: Four measures were taken: before, during, and 2 after the interventions. Algometry was used to assess MPT, a Peltier thermode for HPT using the method of limits, Von Frey filaments for TT, and radial nerve compound action potential. RESULTS: No differences were observed on MPT, HPT, and PNC when 5-kHz current and TENS were compared. However, TT increased 56.2mN (95% confidence interval [CI], 28.8-83.6) in the TENS group compared with the 5-kHz current group during intervention. Compared with sham stimulation during intervention, MPT increased 4.7N (95% CI, 0.3-9.2) using 5-kHz current and 10.4N (95% CI, 3.5-17.3) with TENS. TT increased 17.2mN (95% CI, 4.7-29.7) with 5-kHz current and 73.4mN (95% CI, 47.5-99.2) with TENS. However, HPT increased 1.0°C (95% CI, 0.2-2.0) only with TENS. For the PNC, no differences were found among the 3 groups. CONCLUSIONS: Unmodulated 5-kHz current produced an increase in somatosensory thresholds that was greater than placebo but not when compared with TENS; however, participants perceived 5-kHz currents to be more comfortable and showed more habituation to them.

Efficacy of Transcranial Direct Current Stimulation on Pain Intensity and Functionality in Patients With Knee Osteoarthritis: A Systematic Review and Meta-analysis.

OBJECTIVE: The aim of the study is to investigate whether transcranial direct current stimulation is superior to control groups or other interventions for pain relief and improving functionality in knee osteoarthritis patients. METHODS: PubMed, the Physiotherapy Evidence Database, the Cochrane Library, ProQuest, and Scopus databases were searched from inception to July 2022 to identify randomized clinical trials. The main outcomes were subjective perception of pain intensity measured either with the visual analog scale or with the numeric rating scale; and the functionality, assessed with the Western Ontario and McMaster Universities Osteoarthritis Index. As secondary outcomes, pressure pain threshold, conditioned pain modulation, and its safety were evaluated. RESULTS: We identified 10 randomized clinical trials (634 participants). The results showed an important effect favoring transcranial direct current stimulation for pain relief (mean difference = -1.1 cm, 95% confident interval = -2.1 to -0.2) and for improving functionality (standardized mean difference = -0.6, 95% confident interval = -1.02 to -0.26). There was also a significant improvement in pressure pain threshold (mean difference = 0.9 Kgf/cm 2 , 95% confident interval = 0.1 to 1.6). The certainty of evidence according to Grades of Recommendation Assessment, Development and Evaluation was generally moderate. CONCLUSIONS: Our findings suggest that transcranial direct current stimulation is a safe treatment for reducing pain intensity, improving functionality, and the pressure pain thresholds in patients with knee osteoarthritis.