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 Different Electrical Stimulation Modalities for Pain and Masticatory Function in Temporomandibular Disorders: A Systematic Review and Meta-Analysis.

Temporomandibular disorders comprise a set of conditions that include alterations of the temporomandibular joint and masticatory muscles. Although different modalities of electric currents are widely used for treating temporomandibular disorders, previous reviews have suggested these are ineffective. This systematic review and meta-analysis aimed to determine the effectiveness of different electrical stimulation modalities in patients with temporomandibular disorders for reducing musculoskeletal pain, increasing the range of movement, and improving muscle activity. An electronic search was conducted of randomized controlled trials published until March of 2022 that compared the application of an electrical stimulation therapy versus a sham or control group. The main outcome measure was pain intensity. Seven studies were included in the qualitative analysis and in the quantitative analysis (n = 184 subjects). The overall effect of electrical stimulation on pain reduction was statistically superior to sham/control (MD = -1.12 cm; CI 95%: -1.5 to -0.8), showing moderate heterogeneity of results (I2 = 57%, P = .04). The overall effect on range of movement of the joint (MD = 0.97 mm; CI 95%: -0.3 to 2.2) and muscle activity (SMD = -2.9; CI 95%: -8.1 to 2.3) were not significant. Transcutaneous electrical nerve stimulation (TENS) and high-voltage current stimulation reduces pain intensity clinically in people with temporomandibular disorders with a moderate quality of evidence. On the other hand, there is no evidence of the effect of different electrical stimulation modalities on range of movement and muscle activity in people with temporomandibular disorders with a moderate and low quality of evidence respectively. PERSPECTIVE: TENS and high voltage currents are valid options for the control of pain intensity in patients suffering from temporomandibular disorder. Data suggest clinically relevant changes compared to sham. Healthcare professionals should take this into account as it is inexpensive therapy, has no adverse effects and can be self-administered by patients.

Can Transcranial Direct Current Stimulation Enhance Functionality in Older Adults? A Systematic Review.

Transcranial direct current stimulation (tDCS) is a non-invasive, easy to administer, well-tolerated, and safe technique capable of affecting brain excitability, both at the cortical and cerebellum levels. However, its effectiveness has not been sufficiently assessed in all population segments or clinical applications. This systematic review aimed at compiling and summarizing the currently available scientific evidence about the effect of tDCS on functionality in older adults over 60 years of age. A search of databases was conducted to find randomized clinical trials that applied tDCS versus sham stimulation in the above-mentioned population. No limits were established in terms of date of publication. A total of 237 trials were found, of which 24 met the inclusion criteria. Finally, nine studies were analyzed, including 260 healthy subjects with average age between 61.0 and 85.8 years. Seven of the nine included studies reported superior improvements in functionality variables following the application of tDCS compared to sham stimulation. Anodal tDCS applied over the motor cortex may be an effective technique for improving balance and posture control in healthy older adults. However, further high-quality randomized controlled trials are required to determine the most effective protocols and to clarify potential benefits for older adults.