Short‐term and Long‐term Effects of Electrical Stimulation on Skin Properties

Almalty, Abdul-Majeed; Hamed, Saja; Al-Dabbak, Fuad M.; Shallan, Amjad

doi:10.1002/pri.1543

Cited by 4 publications

(12 citation statements)

References 25 publications

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“…Nevertheless, it is still unknown why vasodilatation under the anode is often different than under the cathode. Possible mechanisms include pH changes in different directions depending on stimulation polarity (Almalty et al, 2013; Ezquerro et al, 2017; Minhas et al, 2010). …”

Section: The Application Of Low Intensity Tes In Human Studies: Aementioning

confidence: 99%

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Antal

Alekseichuk

Bikson

et al. 2017

Clinical Neurophysiology

931

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Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears to be safe. No serious adverse events (SAEs) have been reported so far in over 18,000 sessions administered to healthy subjects, neurological and psychiatric patients, as summarized here. Moderate adverse events (AEs), as defined by the necessity to intervene, are rare, and include skin burns with tDCS due to suboptimal electrode-skin contact. Very rarely mania or hypomania was induced in patients with depression (11 documented cases), yet a causal relationship is difficult to prove because of the low incidence rate and limited numbers of subjects in controlled trials. Mild AEs (MAEs) include headache and fatigue following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1–2 mA and during tACS at higher peak-to-peak intensities above 2 mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly persons, or pregnant women. Combined interventions (e.g., co-application of drugs, electrophysiological measurements, neuroimaging) were not associated with further safety issues. Safety is established for low-intensity ‘conventional’ TES defined as <4 mA, up to 60 min duration per day. Animal studies and modeling evidence indicate that brain injury could occur at predicted current densities in the brain of 6.3–13 A/m2 that are over an order of magnitude above those produced by tDCS in humans. Using AC stimulation fewer AEs were reported compared to DC. In specific paradigms with amplitudes of up to 10 mA, frequencies in the kHz range appear to be safe. In this paper we provide structured interviews and recommend their use in future controlled studies, in particular when trying to extend the parameters applied. We also discuss recent regulatory issues, reporting practices and ethical issues. These recommendations achieved consensus in a meeting, which took place in Göttingen, Germany, on September 6–7, 2016 and were refined thereafter by email correspondence.

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Section: The Application Of Low Intensity Tes In Human Studies: Aementioning

confidence: 99%

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Antal

Alekseichuk

Bikson

et al. 2017

Clinical Neurophysiology

931

728

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“…Users of all types of electrical stimulators must be informed and warned about their adverse effects. Studies have shown that all types and configurations of electrical waves can increase the skin's permeability to topical medications and other chemical products that can be applied to the skin during or after ES sessions 16,18 . Therefore, the manufacturers of these devices must include a warning in the user manual regarding the potential for skin irritation when using chemical products during or immediately after using ES.…”

Section: Discussionmentioning

confidence: 99%

“…found that the transient change in permeability is not restricted to the regions beneath the electrodes but also includes the space between them. 16 And as a consequence of this increased permeability, both drugs and irritant chemicals can more easily permeate the epidermis.…”

Section: Baselinementioning

confidence: 99%

The effect of electrical stimulation on skin vulnerability to irritants

Almalty,

Hamed,

Jebril

et al. 2024

Skin Research and Technology

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PurposeElectrical stimulation (ES) is a widely used technique in the medical field for various purposes. The effect of ES on several skin properties has been investigated; however, its effect on skin vulnerability to irritants remains unknown. This study aimed to investigate the effects of ES application on skin vulnerability to external irritants.Materials and methodsAn experimental study on 12 healthy male subjects (Mean ± SD, 22.9 ± 3.6 years) who completed the study. The subjects were free of skin abnormalities in the volar aspect of both forearms. Three areas were allocated to each forearm and marked as areas 1, 2, and A in the treated forearm, and areas 3, 4, and B in the control forearm. ES was applied to the volar aspect of the treated forearm for 30 min three times a week, for 2 weeks. The effect of ES on skin vulnerability was investigated using 5% and 0.5% sodium lauryl sulfate (SLS) patches applied to both treated and control forearms. The skin response to irritants was evaluated using transepidermal water loss (TEWL) and a visual erythema score 24 h after patch removal.ResultsCompared to the control forearm, ES increased skin permeability and erythema in response to external irritants (SLS), as measured by the visual analog score (Z = 2.75, p = 0.006) and TEWL (p < 0.05), respectively.ConclusionsES escalates skin reactions to low concentrations of irritant substances, such as SLS, in the area between the two electrodes. This emphasizes the use of this substance, and similar irritants should be avoided in areas treated with ES.

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“…This was also evident in the sensitivity analysis of the tissue conductivities, which revealed the potential to change by up to approximately 1.5 V when increasing the conductivity of the different skin layers. The moisture content of the stratum corneum has a high impact on impedance values and may change over the time course of stimulation as the transepidermal water loss increases when applying electrical stimulation [37]. Apart from hydrating the stratum corneum, the increase in transepidermal water loss may introduce more moisture to the electrode-skin interface.…”

Section: Study Limitationsmentioning

confidence: 99%

Increased preferential activation of small cutaneous nerve fibers by optimization of electrode design parameters

Poulsen¹,

Tigerholm²,

Andersen³

et al. 2021

J. Neural Eng.

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Objective. Electrical preferential activation of small nociceptive fibers may be achieved with the use of specialized small area electrodes, however, the existing electrodes are limited to low stimulation intensities. As existing electrodes have been developed empirically, the present study aimed to use computational modeling and optimization techniques to investigate if changes in electrode design parameters could improve the preferential activation of small fibers. Approach. Two finite element models; one of a planar concentric and one of an intra-epidermal electrode were combined with two multi-compartmental nerve fiber models of an Aδ-fiber and an Aβ-fiber. These two-step hybrid models were used for the optimization of four electrode parameters; anode area, anode–cathode distance, cathode area, and cathode protrusion. Optimization was performed using a gradient-free bounded Nelder–Mead algorithm, to maximize the current activation threshold ratio between the Aβ-fiber model and the Aδ-fiber model. Main results. All electrode parameters were optimal at their lower bound, except the cathode protrusion, which was optimal a few micrometers above the location of the Aδ-fiber model. A small cathode area is essential for producing a high current density in the epidermal skin layer enabling activation of small fibers, while a small anode area and anode–cathode distance are important for the minimization of current spread to deeper tissues, making it less likely to activate large fibers. Combining each of the optimized electrode parameters improved the preferential activation of small fibers in comparison to existing electrodes, by increasing the activation threshold ratio between the two nerve fiber types. The maximum increase in the activation threshold ratio was 289% and 595% for the intra-epidermal and planar concentric design, respectively. Significance. The present study showed that electrical preferential small fiber activation can be improved by electrode design. Additionally, the results may be used for the production of an electrode that could potentially be used for clinical assessment of small fiber neuropathy.

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Short‐term and Long‐term Effects of Electrical Stimulation on Skin Properties

Abstract: Electrical stimulation caused temporary increase in TEWL with no effects on other skin properties.

Cited by 4 publications

References 25 publications

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines

The effect of electrical stimulation on skin vulnerability to irritants

Increased preferential activation of small cutaneous nerve fibers by optimization of electrode design parameters

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