High-intensity Transcutaneous Electrical Stimulation Research Articles

Factors associated with high pain intensity during wound care procedures: A model

The most common wound care procedures (WPCs) performed on open wounds are dressing changes and wound cleansing. Dressing changes cause moderate to severe pain in 74% of patients, nearly half (36%) of whom experience severe pain (rated as 8-10 on a 10-point numeric rating scale). The purpose of this paper is to propose a model of clinically accessible factors that can be tested in order to develop a clinical tool to identify which patients are likely to experience high intensity pain during nonoperative WCPs, such as dressing changes. Although multiple factors are known to be associated with pain, the factors selected for this model were limited to those that (1) are supported based on evidence and/or pain mechanisms and (2) are readily accessible to clinicians/practitioners and can be tested as a prediction tool to be used prior to WCPs. This model may be helpful to identify those likely to experience high intensity pain during WCPs. In this way, use of aggressive pain management strategies, including specialty dressings, pharmacologic analgesics, and/or non-pharmacological strategies, such as high intensity transcutaneous electrical stimulation.

Captured by the pain: Pain steady-state evoked potentials are not modulated by selective spatial attention

Attention has been shown to affect the neural processing of pain. However, the exact mechanisms underlying this modulation remain unknown. Here, we used a new method called pain steady-state evoked potentials (PSSEPs) to investigate whether selective spatial attention affects EEG responses to tonic painful stimuli. In general, steady-state evoked potentials reflect changes in the EEG spectrum at a certain frequency that correspond to the frequency of a train of applied stimuli.In this study, high intensity transcutaneous electrical stimulation was delivered to both hands simultaneously with 31Hz and 37Hz, respectively. Subject׳s attention was directed to one of the two trains of stimulation in order to detect a small gap that was occasionally interspersed into the stimulus trains. Thereby, they had to ignore the stimulation applied to the other hand.Results show that PSSEPs were induced at 31Hz and 37Hz at frontal and central electrodes. PSSEPs occurred contralaterally to the respective hand stimulated with that frequency. Surprisingly, the magnitude of PSSEPs was not modulated by spatial attention towards one of the two stimuli. Our results indicate that attention can hardly be shifted between two simultaneously applied tonic painful stimulations.

The Effect of Transcutaneous Electrical Stimulation on Spinal Motor Neuron Excitability in People Without Known Neuromuscular Diseases: The Roles of Stimulus Intensity and Location

The Hoffmann reflex (H-reflex) is widely acknowledged as an indirect indicator of spinal motor neuron excitability. The purpose of this study was to determine whether transcutaneous electrical stimulation (TES), applied over the dorsiflexors or plantar flexors of the ankle, would alter the soleus muscle's H-reflex. Attention was focused on the roles of stimulus intensity and location. Thirty-two volunteers without known neuromuscular diseases (17 women [53%]; mean years of age=27, SD=7.3, range=21-48) were studied. Subjects were randomly assigned to 1 of 4 groups, and TES was administered for 15 minutes. Stimulation site and intensity varied according to group assignment. H-reflexes were recorded before and for 10 minutes after TES. H-reflex amplitudes increased following TES at sensory threshold, whereas H-reflex amplitudes did not change following TES at 1.5 times motor threshold. The site of stimulation did not influence the resulting H-reflexes. Low-intensity TES increases H-reflex amplitudes (and presumably the excitability of spinal motor neurons to Ia afferent input) in subjects without known neuromuscular diseases. High-intensity TES had little influence on H-reflex amplitudes.

Differential antinociceptive effect of transcutaneous electrical stimulation on pain behavior sensitive or insensitive to phentolamine in neuropathic rats

The effects of transcutaneous electrical stimulation and systemic injection of phentolamine, a non-specific alpha-adrenergic antagonist, on the behavioral signs of mechanical allodynia and cold hyperalgesia in rats with nerve injury were investigated. Mechanical allodynia and cold hyperalgesia were evaluated by measuring the paw withdrawal frequency (PWF) resulting from repetitive application of a von Frey hair and the paw lift duration (PLD) at a cold temperature, respectively. After a unilateral nerve injury, both PWF and PLD increased in the injured hind paw. Application of low-frequency, high-intensity transcutaneous electrical stimulation (LFHI-TES) to the injured hind paw depressed the injury-induced increased PWF, whereas it had no effect on the injury-induced increased PLD. Naloxone reversed the LFHI-TES produced depression of PWF. Intraperitoneal administration of phentolamine depressed the injury-induced increased PLD without affecting the injury-induced increased PWF. Our results suggest that LFHI-TES, which activates the endogenous opioid systems, produces an antinociceptive effect that appears to be related to whether or not the pain is mediated by sympathetic activity.

Electrophysiological evidence for the antinociceptive effect of transcutaneous electrical stimulation on mechanically evoked responsiveness of dorsal horn neurons in neuropathic rats

Using a rat model of peripheral neuropathy induced by a tight ligation of 5–6 spinal nerves, the effects of transcutaneous electrical stimulation on the mechanical responses of wide dynamic range (WDR) dorsal horn neurons were investigated. The responses of the WDR neurons to both the brush and pinch stimuli were found to be enhanced in the neuropathic rats compared to those in the normal rats. These enhanced responses were depressed by low-frequency and high-intensity transcutaneous electrical stimulation (2 Hz, 4–5 mA) applied to the somatic receptive field. The durations of the depressive effects on the brush responses ranged between 30 and 45 min and those on the pinch responses were 60–90 min. These results imply that the transcutaneous electrical stimulation used here produces an antinociceptive effect via a depressive action on the enhanced mechanical responsiveness of the spinal neurons in this rat model of peripheral neuropathy.

Transcutaneous electrical stimulation applied to the infratrochlear nerve induces a homatropine-resistant miosis in humans

1. Both high- and low-intensity transcutaneous electrical stimuli were applied to the emergence of the infratrochlear nerve in 18 healthy subjects. The effect on the size of the homolateral pupil was investigated. The width of the pupil was also measured when high-intensity transcutaneous electrical stimulation was applied to the contralateral side. 2. The high-intensity pulse resulted in constriction of the pupil when the stimulation was homolateral. The miosis was slow in onset (120 s latency) and long-lasting (80 s). No pupillary changes were detected after either ipsilateral low-intensity or contralateral high-intensity stimuli. 3. In 11 healthy subjects, the pupillary response to transcutaneous electrical stimulation was evaluated during iris parasympathetic blockade induced by homatropine eyedrops. The disappearance of the light reflex due to homatropine was considered an index of the parasympathetic blockade. Afterwards, a high-intensity pulse was transcutaneously delivered to the emergence of the infratrochlear nerve and the ipsilateral pupil size was measured. 4. A reduction in the pupillary size followed the electrical stimulation, still under the effect of homatropine which abolished the light reflex. The time course of this pupillary constriction was similar to that seen without the influence of homatropine. 5. The findings suggest that homolateral miosis, observed after unilateral high-intensity stimulation of the infratrochlear nerve, does not stem from cholinergic activation. It has been suggested that miosis induced by transcutaneous electrical stimulation may be due to an antidromic activation of the iris sensory fibres.