Estimulación eléctrica nerviosa transcutánea como tratamiento de la espasticidad: una revisión sistemática

Immediate Neurophysiological effect of electrical stimulation via dry needling on H-reflex in post stroke spasticity

BACKGROUND

Many non-pharmacological interventions have been proposed for spasticity modulation in spastic stroke subjects.

OBJECTIVE

To investigate the immediate effect of dry needling (DN), electrical stimulation (ES), and dry needling with intramuscular electrical stimulation (DN+IMES) on H-reflex in post-stroke spasticity.

METHODS

Spastic subjects with stroke (N = 90) (55-85 years) were evaluated after 1 month of stroke onset using Modified Ashworth Scale (MAS) score ≥1. Subjects were randomly allocated to receive one session of DN - Soleus (N = 30), ES - posterior lateral side of the leg with 100 Hz and 250 μs pulse width (N = 30), or DN+IMES - Soleus (N = 30). MAS, H-reflex, maximum latency, H-amplitude, M-amplitude and H/M ratio, were recorded before and after one session of intervention. Relationships for each variable within group or the difference among groups were calculated by effect size.

RESULTS

Significant decrease in H/M ratio in Gastrocnemius and Soleus at post-treatment within DN group (P = .024 and P = .029, respectively), large effect size (d = 0.07 and 0.62, respectively); and DN+IMES group (P = .042 and P = .001, respectively), large effect size (d = 0.69 and 0.71, respectively). No significant differences in all variables at pre-treatment and post-treatment was recorded among ES, DN, and DN+IMES groups. Significant decrease in MAS was recorded at post-treatment compared to pre-treatment within ES group (P = .002), DN group (P = .0001), and DN+IMES group (P = .0001), but not significant (P > .05) among three groups at pre-treatment (P = .194) and post-treatment (P = .485).

CONCLUSIONS

Single session of DN, ES, and the DN+IMES can significantly modulate post-stroke spasticity by possible bottom-up regulation mechanisms.

Treatment of spasticity

Spasticity is characterized by an enhanced size and reduced threshold for activation of stretch reflexes and is associated with "positive signs" such as clonus and spasms, as well as "negative features" such as paresis and a loss of automatic postural responses. Spasticity develops over time after a lesion and can be associated with reduced speed of movement, cocontraction, abnormal synergies, and pain. Spasticity is caused by a combination of damage to descending tracts, reductions in inhibitory activity within spinal cord circuits, and adaptive changes within motoneurons. Increased tone, hypertonia, can also be caused by changes in passive stiffness due to, for example, increase in connective tissue and reduction in muscle fascicle length. Understanding the cause of hypertonia is important for determining the management strategy as nonneural, passive causes of stiffness will be more amenable to physical rather than pharmacological interventions. The management of spasticity is determined by the views and goals of the patient, family, and carers, which should be integral to the multidisciplinary assessment. An assessment, and treatment, of trigger factors such as infection and skin breakdown should be made especially in people with a recent change in tone. The choice of management strategies for an individual will vary depending on the severity of spasticity, the distribution of spasticity (i.e., whether it affects multiple muscle groups or is more prominent in one or two groups), the type of lesion, and the potential for recovery. Management options include physical therapy, oral agents; focal therapies such as botulinum injections; and peripheral nerve blocks. Intrathecal baclofen can lead to a reduction in required oral antispasticity medications. When spasticity is severe intrathecal phenol may be an option. Surgical interventions, largely used in the pediatric population, include muscle transfers and lengthening and selective dorsal root rhizotomy.

Use of Transcutaneous Electrical Nerve Stimulation (TENS) for the Recovery of Oral Function after Orthognathic Surgery

The oral functions of patients are markedly diminished immediately after orthognathic surgery, and novel approaches are needed to accelerate their recovery. The aim of this study was to examine the usefulness of weekly applications of transcutaneous electrical nerve stimulation (TENS) for this purpose, based on the evidence of its effectiveness in other types of patients with muscle alterations. Maximum jaw opening, bite force, pain, and facial inflammation were compared between patients receiving TENS and those receiving sham-TENS for 30 min at baseline and weekly over a four-week period after orthognathic surgery and were also compared between the before and after of each procedure. TENS was applied at 220 Hz, applying the maximum intensity tolerated by each individual patient. The TENS procedure was identical for all patients, but the device was not turned on in the sham-TENS group. Patients were blinded to their group membership. Results were analyzed separately in skeletal class II and III patients. Improvements in jaw opening and inflammation were significantly greater in the TENS than in the sham-TENS group, attributable to the muscle relaxation achieved with the procedure. Research is warranted on the benefits of a more frequent application of TENS.

Low-Intensity Focused Ultrasound Alleviates Spasticity and Increases Expression of the Neuronal K-Cl Cotransporter in the L4–L5 Sections of Rats Following Spinal Cord Injury

Low-intensity focused ultrasound (LIFU) has been shown to provide effective activation of the spinal cord neurocircuits. The aim of this study was to investigate the effects of LIFU in order to alleviate spasticity following spinal cord injury (SCI) by activating the spinal neurocircuits and increasing the expression of the neuronal K-Cl cotransporter KCC₂. Adult male Sprague Dawley (SD) rats (220–300 g) were randomly divided into a sham control group, a LIFU⁻ group, and a LIFU⁺ group. The mechanical threshold hold (g) was used to evaluate the behavioral characteristics of spasm. Electromyography (EMG) was used to assess activation of the spinal cord neurocircuits and muscle spontaneous contraction. Spasticity was assessed by frequency-dependent depression (FDD). The expression of KCC₂ of the lumbar spinal cord was determined via western blot (WB) and immunofluorescence (IF) staining. The spinal cord neurocircuits were activated by LIFU simulation, which significantly reduced the mechanical threshold (g), FDD, and EMG recordings (s) after 4 weeks of treatment. WB and IF staining both demonstrated that the expression of KCC₂ was reduced in the LIFU⁻ group (P < 0.05). After 4 weeks of LIFU stimulation, expression of KCC₂ had significantly increased (P < 0.05) in the LIFU⁺ group compared with the LIFU⁻ group. Thus, we hypothesized that LIFU treatment can alleviate spasticity effectively and upregulate the expression of KCC₂ in the L4–L5 section of SCI rats.

Invasive Physiotherapy as a Treatment of Spasticity: A Systematic Review

Introduction

Nowadays, a set of novel physiotherapy techniques have emerged, in which the physical agent used to try to reduce spasticity is applied percutaneously, specifically, through the patient’s skin. The aim of this work is to encompass all the invasive techniques used in spasticity in a single article, updating the existing bibliography.

Methodology

A systematic review was carried out between December 2020 and April 2021 in the Web of Science, Scopus and PubMed databases, selecting the clinical trials that used acupuncture, electroacupuncture or dry needling as a treatment for spasticity. Sixteen clinical trials were included, summarizing all the study characteristics and the outcome measures, at last the evidence was described for their results.

Results

Most of the studies find a difference of significant decrease in spasticity between the subjects of the experimental groups. Only four studies found no significant changes in spasticity. All the studies are carried out together with the conventional physiotherapy treatment in spasticity.

Conclusion

Treatment with invasive physiotherapy, combined with conventional physiotherapy, seems to have positive effects in reducing spasticity, although more studies are needed to improve the heterogeneity of the interventions and to assess their long-term effectiveness.

Effects of 60 Min Electrostimulation With the EXOPULSE Mollii Suit on Objective Signs of Spasticity

Background: The EXOPULSE Mollii method is an innovative full-body suit approach for non-invasive electrical stimulation, primarily designed to reduce disabling spasticity and improve motor function through the mechanism of reciprocal inhibition. This study aimed to evaluate the effectiveness of one session of stimulation with the EXOPULSE Mollii suit at different stimulation frequencies on objective signs of spasticity and clinical measures, and the subjective perceptions of the intervention.

Methods: Twenty patients in the chronic phase after stroke were enrolled in a cross-over, double-blind controlled study. Electrical stimulation delivered through EXOPULSE Mollii was applied for 60 min at two active frequencies (20 and 30 Hz) and in OFF-settings (placebo) in a randomized order, every second day. Spasticity was assessed with controlled-velocity passive muscle stretches using the NeuroFlexor hand and foot modules. Surface electromyography (EMG) for characterizing flexor carpi radialis, medial gastrocnemius, and soleus muscles activation, Modified Ashworth Scale and range of motion were used as complementary tests. Finally, a questionnaire was used to assess the participants' perceptions of using the EXOPULSE Mollii suit.

Results: At group level, analyses showed no significant effect of stimulation at any frequency on NeuroFlexor neural component (NC) and EMG amplitude in the upper or lower extremities (p > 0.35). Nevertheless, the effect was highly variable at the individual level, with eight patients exhibiting reduced NC (>1 N) in the upper extremity after stimulation at 30 Hz, 5 at 20 Hz and 3 in OFF settings. All these patients presented severe spasticity at baseline, i.e., NC > 8 N. Modified Ashworth ratings of spasticity and range of motion did not change significantly after stimulation at any frequency. Finally, 75% of participants reported an overall feeling of well-being during stimulation, with 25% patients describing a muscle-relaxing effect on the affected hand and/or foot at both 20 and 30 Hz.

Conclusions: The 60 min of electrical stimulation with EXOPULSE Mollii suit did not reduce spasticity consistently in the upper and lower extremities in the chronic phase after stroke. Findings suggest a need for further studies in patients with severe spasticity after stroke including repeated stimulation sessions.

Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT04076878, identifier: NCT04076878.

Does TENS Reduce the Intensity of Acute and Chronic Pain? A Comprehensive Appraisal of the Characteristics and Outcomes of 169 Reviews and 49 Meta-Analyses

Background and Objectives: Uncertainty about the clinical efficacy of transcutaneous electric nerve stimulation (TENS) to alleviate pain spans half a century. There has been no attempt to synthesise the entire body of systematic review evidence. The aim of this comprehensive review was to critically appraise the characteristics and outcomes of systematic reviews evaluating the clinical efficacy of TENS for any type of acute and chronic pain in adults. Materials and Methods: We searched electronic databases for full reports of systematic reviews of studies, overviews of systematic reviews, and hybrid reviews that evaluated the efficacy of TENS for any type of clinical pain in adults. We screened reports against eligibility criteria and extracted data related to the characteristics and outcomes of the review, including effect size estimates. We conducted a descriptive analysis of extracted data. Results: We included 169 reviews consisting of eight overviews, seven hybrid reviews and 154 systematic reviews with 49 meta-analyses. A tally of authors' conclusions found a tendency toward benefits from TENS in 69/169 reviews, no benefits in 13/169 reviews, and inconclusive evidence in 87/169 reviews. Only three meta-analyses pooled sufficient data to have confidence in the effect size estimate (i.e., pooled analysis of >500 events). Lower pain intensity was found during TENS compared with control for chronic musculoskeletal pain and labour pain, and lower analgesic consumption was found post-surgery during TENS. The appraisal revealed repeated shortcomings in RCTs that have hindered confident judgements about efficacy, resulting in stagnation of evidence. Conclusions: Our appraisal reveals examples of meta-analyses with 'sufficient data' demonstrating benefit. There were no examples of meta-analyses with 'sufficient data' demonstrating no benefit. Therefore, we recommend that TENS should be considered as a treatment option. The considerable quantity of reviews with 'insufficient data' and meaningless findings have clouded the issue of efficacy. We offer solutions to these issues going forward.

Intensity matters: Therapist-dependent dose of spinal transcutaneous electrical nerve stimulation

The intensity used during transcutaneous electrical nerve stimulation (TENS) in both, clinical practice and research studies, is often based on subjective commands such as “strong but comfortable sensation”. There is no consensus regarding the effectiveness dose of TENS. The objective was to determine the difference in the effect of spinal TENS on soleus H-reflex modulation when applied by two therapists instructed to apply the stimulation at a “strong but comfortable” intensity. Twenty healthy volunteers divided into two groups: Therapist 1 (n = 10) and Therapist 2 (n = 10). Both therapist applied spinal TENS and sham stimulation at the T10–12 spinal level for 40min in random order to each subject, at an intensity designed to produce a “strong but comfortable” sensation. To avoid habituation, the intensity was adjusted every 2min. Soleus H-reflex was recorded before, during, and 10min after TENS by an observer blinded to the stimulus applied. Despite the instruction to apply TENS at a “strong comfortable” level, a significant difference in current density was identified: Therapist 1 (0.67mA/cm², SD 0.54) applied more than Therapist 2 (0.53mA/cm², SD 0.57; p<0.001) at the onset of the intervention. Maximal peak-to-peak H-reflex amplitude was inhibited significantly more 10min following TENS applied by Therapist 1 (-0.15mV, SD 0.16) compared with Therapist 2 (0.04mV, SD 0.16; p = 0.03). Furthermore, current density significantly correlated with the inhibitory effect on peak-to-peak Soleus H-reflex amplitude 10 min after stimulation (Rho = -0.38; p = 0.04). TENS intensity dosage by the therapist based on the subjective perception of the participants alone is unreliable and requires objective standardization. In addition, higher current density TENS produced greater inhibition of the Soleus H-reflex.