Bilateral Transcutaneous Electrical Nerve Stimulation Improves Lower-Limb Motor Function in Subjects With Chronic Stroke: A Randomized Controlled Trial

Non-invasive vagus nerve stimulation and exercise capacity in healthy volunteers: a randomized trial

BACKGROUND AND AIMS

Vagal parasympathetic dysfunction is strongly associated with impaired exercise tolerance, indicating that coordinated autonomic control is essential for optimizing exercise performance. This study tested the hypothesis that autonomic neuromodulation by non-invasive transcutaneous vagus nerve stimulation (tVNS) can improve exercise capacity in humans.

METHODS

This single-centre, randomized, double-blind, sham-controlled, crossover trial in 28 healthy volunteers evaluated the effect of bilateral transcutaneous stimulation of vagal auricular innervation, applied for 30 min daily for 7 days, on measures of cardiorespiratory fitness (peak oxygen consumption (VO2peak)) during progressive exercise to exhaustion. Secondary endpoints included peak work rate, cardiorespiratory measures, and the whole blood inflammatory response to lipopolysaccharide ex vivo.

RESULTS

tVNS applied for 30 min daily over 7 consecutive days increased VO2peak by 1.04 mL/kg/min (95% CI: .34-1.73; P = .005), compared with no change after sham stimulation (-0.54 mL/kg/min; 95% CI: -1.52 to .45). No carry-over effect was observed following the 2-week washout period. tVNS increased work rate (by 6 W; 95% CI: 2-10; P = .006), heart rate (by 4 bpm; 95% CI: 1-7; P = .011), and respiratory rate (by 4 breaths/min; 95% CI: 2-6; P < .001) at peak exercise. Analysis of the whole blood transcriptomic response to lipopolysaccharide in serial samples obtained from five participants showed that tVNS reduced the inflammatory response.

CONCLUSIONS

Non-invasive vagal stimulation improves measures of cardiorespiratory fitness and attenuates inflammation, offering an inexpensive, safe, and scalable approach to improve exercise capacity.

Effect of electrical stimulation in the treatment on patients with foot drop after stroke: a systematic review and network meta-analysis

OBJECTIVE

To systematically evaluate the efficacy of electrical stimulation (ES) in the treatment of patients with foot drop (FD) after stroke, and to compare the efficacy of different types of ES.

DATA SOURCES

We searched 5 English database (PubMed, Web of Science, Embase, Cochrane Library and Scopus) and 4 Chinese databases (China National Knowledge Infrastructure (CNKI), SinoMed (CBM), VIP and Wanfang Data) from inception to June, 2024.

DATA SYNTHESIS

Traditional meta-analysis and network meta-analysis were performed using RevMan5.4 software and Stata 14.0 software respectively. A total of 37 RCTs were included, involving 2309 patients. The results of the traditional meta-analysis showed that compared with CRT, ES combined with CRT was effective in improving the range of motion (ROM) of ankle dorsiflexion in patients with FD after stroke and significantly improved the fugl-meyer assessment of lower extremity (FMA-LE) scores. For patients with FD with different disease duration, the subgroup analysis results showed that the ES improved the ROM of ankle dorsiflexion of patients in recovery phases (1-6 months) better than those in the acute phases (≤ 1 month) and sequelae phases (≥ 6 months), but the overall results of the three groups were not significantly different. The ES improved the lower limb motor function of patients in the recovery phases better than those in the acute phases, and the efficacy was not significant in patients in the sequelae phases (P > 0.05). The results of network meta-analysis showed that the best probability of improving the dorsiflexion angle of the ankle was electroacupuncture (EA) > transcranial direct current stimulation (tDCS) > transcutaneous electrical nerve stimulation (TENS) > functional electrical stimulation (FES) > neuromuscular electrical stimulation (NMES) > electromyographic biofeedback therapy (EMGBFT) > conventional rehabilitation therapy (CRT); the best probability of improving the dorsiflexion angle of the ankle was EA > EMGBFT > tDCS > FES > TENS > NMES > CRT.

CONCLUSIONS

The current evidence showed that the ES combined with CRT can effectively improve the ROM of ankle dorsiflexion and lower limb motor function in patients with FD after stroke, especially the patients in recovery phases. Among the different types of ES, EA had the best effect than other types of ES.

Neuroplasticity and Nervous System Recovery: Cellular Mechanisms, Therapeutic Advances, and Future Prospects

Neuroplasticity, the ability of the nervous system to adapt structurally and functionally in response to environmental interactions and injuries, is a cornerstone of recovery in the central (CNS) and peripheral nervous systems (PNS). This review explores the mechanisms underlying neuroplasticity, focusing on the dynamic roles of cellular and molecular processes in recovery from nervous system injuries. Key cellular players, including Schwann cells, oligodendrocytes, and neural stem cells, are highlighted for their contributions to nerve repair, myelination, and regeneration. Advances in therapeutic interventions, such as electrical stimulation, bioluminescent optogenetics, and innovative nerve grafting techniques, are discussed alongside their potential to enhance recovery and functional outcomes. The molecular underpinnings of plasticity, involving synaptic remodeling, homeostatic mechanisms, and activity-dependent regulation of gene expression, are elucidated to illustrate their role in learning, memory, and injury repair. Integrating emerging technologies and therapeutic approaches with a foundational understanding of neuroplasticity offers a pathway toward more effective strategies for restoring nervous system functionality after injury.

Spatial Distribution Dynamics of Sensory Disturbances in the Treatment of Obesity-Related Meralgia Paresthetica Using Transcutaneous Electrical Nerve Stimulation

Background: To date, there have been no studies on the dynamics of areas of pain, paraesthesia and hypoesthesia after the use of various transcutaneous electrical nerve stimulation in the treatment of meralgia paresthetica. Methods: In this pilot study, we observed 68 patients with obesity-related bilateral meralgia paresthetica. Pain syndrome, paraesthesia symptoms, and hypoesthesia were evaluated using 10-point scores. In addition, pain drawing (PD) was used to determine the area of the spatial distribution of pain syndrome and paraesthesia symptoms, and body drawing was used to determine the area of hypoesthesia. Sham TENS was performed in the control group, and effective TENS was performed in the treatment group. The treatment group consisted of two subgroups. One subgroup underwent HF-LA TENS, and the second subgroup underwent LF-HA TENS. Results: Despite the greatest analgesic effect observed from HF-LA TENS, which was assessed using scoring methods, during and after treatment, the reduction in the area of pain and paraesthesia symptoms and the area of hypoesthesia was moderate, short-term, and reversible. In contrast, LF-HA TENS had a pronounced analgesic and sustained anti-paraesthesia effect, manifested by a noticeable decrease in pain and paraesthesia symptoms area in PD, gradually increasing during the first 2 months of follow-up and accompanied by an irreversible prolonged decrease in the area of hypoesthesia. Conclusion: The areas of paraesthesia and hypoesthesia correlate with affective reactions to long-term chronic pain, which noticeably regress under the influence of LF-HA TENS compared to HF-LA TENS.

Assessing the fall risk with Stay Independent Questionnaire in people with stroke

Objectives

This study aimed to assess the psychometric properties of the Chinese version of the Stay Independent Questionnaire (C-SIQ) in evaluating individuals with stroke.

Design

The study adopted a cross-sectional design.

Setting

The research was conducted at a university-based neurorehabilitation center.

Participants

The study included a total of 100 individuals with stroke and 49 healthy older adults.

Methods

On Day 1, both individuals with stroke and healthy older adults underwent assessments using the C-SIQ. Additionally, individuals with stroke were evaluated using the Fugl-Meyer Assessment of Lower Extremity (FMA-LE), ankle dorsiflexion and plantarflexion strength, Berg Balance Scale (BBS), Timed-Up and Go Test (TUG), 10-meter walk test (10 mWT), Activities-specific Balance Confidence (ABC) Scale, Stroke Impact Scale (SIS), and Community Integration Measure (CIM). On Day 2 (7 days after Day 1), individuals with stroke were reassessed using the C-SIQ.

Results

Individuals with stroke exhibited a higher C-SIQ score (6.22 ± 2.98) compared to healthy older adults (1.59 ± 2.01). The C-SIQ demonstrated good test-retest reliability (intraclass correlation coefficient = 0.847) and internal consistency (Cronbach's alpha = 0.709). The Minimal Detectable Change in C-SIQ score was calculated as 3.05. Exploratory factor analysis revealed four factors with eigenvalues ≥1.0, explaining 57.17% of the total variance. The C-SIQ score exhibited significant correlations (ranging from -0.553 to 0.362) with completion times of the TUG and 10 mWT, FMA-LE, BBS, ABC, SIS, CIM score, paretic ankle dorsiflexion strength, and 6 mWT distance. A cut-off score of 2.5 was identified as the optimal threshold for discriminating fall risk between individuals with stroke and healthy controls.

Conclusion

The C-SIQ emerges as a reliable and valid tool for evaluating fall risk in individuals with stroke, showcasing strong correlations with key measures such as TUG times, 10 mWT, FMA-LE, BBS, ABC, SIS, CIM score, paretic ankle dorsiflexion strength, and 6 mWT distance. The C-SIQ demonstrated good test-retest reliability and internal consistency. Exploratory factor analysis revealed that this is a four factors assessment tool. The identified cut-off score of 2.5 effectively distinguishes fall risk between individuals with stroke and healthy controls.

Effectiveness of social media with or without wearable devices to improve physical activity and reduce sedentary behavior: A randomized controlled trial of Chinese postgraduates

The present study was aimed to verify whether an integrating of wearable activity tracker device and a social media intervention strategy would be better than a standalone social media intervention for improving physical activity (PA) and reducing sedentary time for Chinese postgraduate population. A total of 42 full-time postgraduate students participated in this study, which were randomized to receive a 4-week social media intervention through WeChat either with (Wearable Device group) or without (control group) a wearable activity tracker device. Energy expenditure, step counts, moderate to vigorous physical activity time (MVPA) and sedentary time were assessed before and after the intervention. Besides, anthropometric parameters of body weight, body mass index, body fat rate, waist-to-hip ratio, as well as self-reported quality of life were also evaluated. It was found that both energy expenditure and step counts were significantly increased, while sedentary time was significantly reduced during the post-intervention test compared to the baseline test for Wearable Device group. No significant difference of PA was found for the control group. The results demonstrated that the integrating of wearable activity tracker device and a social media intervention was effective in promoting PA, while a standalone social media intervention may have no effect on the influence of PA for Chinese postgraduates.

Transcutaneous Electrical Nerve Stimulation (TENS) Alleviates Brain Ischemic Injury by Regulating Neuronal Oxidative Stress, Pyroptosis, and Mitophagy

Background

As a noninvasive treatment, transcutaneous electrical nerve stimulation (TENS) has been utilized to treat various diseases in clinic. However, whether TENS can be an effective intervention in the acute stage of ischemic stroke still remains unclear. In the present study, we aimed to explore whether TENS could alleviate brain infarct volume, reduce oxidative stress and neuronal pyroptosis, and activate mitophagy following ischemic stroke.

Methods

TENS was performed at 24 h after middle cerebral artery occlusion/reperfusion (MCAO/R) in rats for 3 consecutive days. Neurological scores, the volume of infarction, and the activity of SOD, MDA, GSH, and GSH-px were measured. Moreover, western blot was performed to detect the related protein expression, including Bcl-2, Bax, TXNIP, GSDMD, caspase-1, NLRP3, BRCC3, HIF-1α, BNIP3, LC3, and P62. Real-time PCR was performed to detect NLRP3 expression. Immunofluorescence was performed to detect the levels of LC3.

Results

There was no significant difference of neurological deficit scores between the MCAO group and the TENS group at 2 h after MCAO/R operation (P > 0.05), while the neurological deficit scores of TENS group significantly decreased in comparison with MCAO group at 72 h following MACO/R injury (P < 0.05). Similarly, TENS treatment significantly reduced the brain infarct volume compared with the MCAO group (P < 0.05). Moreover, TENS decreased the expression of Bax, TXNIP, GSDMD, caspase-1, BRCC3, NLRP3, and P62 and the activity of MDA as well as increasing the level of Bcl-2, HIF-1α, BNIP3, and LC3 and the activity of SOD, GSH, and GSH-px (P < 0.05).

Conclusions

In conclusion, our results indicated that TENS alleviated brain damage following ischemic stroke via inhibiting neuronal oxidative stress and pyroptosis and activating mitophagy, possibly via the regulation of TXNIP, BRCC3/NLRP3, and HIF-1α/BNIP3 pathways.

A scoping review of the contralateral effects of unilateral peripheral stimulation on neuromuscular function

It is known that resistance exercise using one limb can affect motor function of both the exercised limb and the unexercised contralateral limb, a phenomenon termed cross-education. It has been suggested that cross-education has clinical implications, e.g. in rehabilitation for orthopaedic conditions or post-stroke paresis. Much of the research on the contralateral effect of unilateral intervention on motor output is based on voluntary exercise. This scoping review aimed to map the characteristics of current literature on the cross-education caused by three most frequently utilised peripheral neuromuscular stimulation modalities in this context: electrical stimulation, mechanical vibration and percutaneous needling, that may direct future research and translate to clinical practice. A systematic search of relevant databases (Ebsco, ProQuest, PubMed, Scopus, Web of Science) through to the end of 2020 was conducted following the PRISMA Extension for Scoping Review. Empirical studies on human participants that applied a unilateral peripheral neuromuscular stimulation and assessed neuromuscular function of the stimulated and/or the unstimulated side were selected. By reading the full text, the demographic characteristics, context, design, methods and major findings of the studies were synthesised. The results found that 83 studies were eligible for the review, with the majority (53) utilised electrical stimulation whilst those applied vibration (18) or needling (12) were emerging. Although the contralateral effects appeared to be robust, only 31 studies claimed to be in the context of cross-education, and 25 investigated on clinical patients. The underlying mechanism for the contralateral effects induced by unilateral peripheral stimulation remains unclear. The findings suggest a need to enhance the awareness of cross-education caused by peripheral stimulation, to help improve the translation of theoretical concepts to clinical practice, and aid in developing well-designed clinical trials to determine the efficacy of cross-education therapies.

Grey Relational Analysis of Lower Limb Muscle Fatigue and Pedalling Performance Decline of Elite Athletes during a 30-Second All-Out Sprint Cycling Exercise

The 30-second all-out sprint cycling exercise is a classical sport capacity evaluation method, which may cause severe lower limb muscle fatigue. However, the relationship between lower limb muscle fatigue and the decline in exercise performance during 30-second sprint cycling remains unclear. In this study, ten cyclists volunteered to participate in a 30-second all-out sprint cycling while power, cadence, and surface electromyographic (EMG) signals of eight lower limb muscles were recorded during the exercise. EMG mean frequency (MNF) of each lower limb muscle group was computed for every 3-second epoch based on wavelet packet transformation. Grey relational grades between pedalling performance and the EMG MNF of each lower limb muscle group during the whole process were calculated. The results demonstrated that EMG MNF of the rectus femoris (RF), vastus (VAS), gastrocnemius (GAS), and tibialis anterior (TA) progressively tired during a 30-second all-out sprint cycling exercise. Of the muscles evaluated, the degree of fatigue of TA showed the greatest association with exercise performance decline, whereas the muscle fatigue of RF, VAS, and GAS also significantly impacted exercise performance during a 30-second all-out sprint cycling exercise.

Bilateral Transcutaneous Electrical Nerve Stimulation Improves Upper Limb Motor Recovery in Stroke: A Randomized Controlled Trial

BACKGROUND AND PURPOSE

Recent evidence has shown bilateral transcutaneous electrical nerve stimulation (Bi-TENS) combined with task-oriented training (TOT) to be superior to unilateral transcutaneous electrical nerve stimulation (Uni-TENS)+TOT in improving lower limb motor functioning following stroke. However, no research explored the effect of Bi-TENS+TOT in improving upper limb motor recovery. This study aimed to compare Bi-TENS+TOT with Uni-TENS+TOT, Placebo transcutaneous electrical nerve stimulation (Placebo-TENS)+TOT, and no treatment (Control) groups in upper limb motor recovery.

METHODS

This is a 4-group parallel design. One hundred and twenty subjects were given either Bi-TENS+TOT, Uni-TENS+TOT, Placebo-TENS+TOT, or Control without treatment in this randomized controlled trial. Twenty 60-minute sessions were administered 3× per week for 7 weeks. The outcome measure was the Fugl-Meyer Assessment of Upper Extremity, which was assessed at baseline, after 10 sessions (mid-intervention) and 20 sessions (post-intervention) of intervention, and at 1- and 3-month follow-up.

RESULTS

Patients in the Bi-TENS+TOT group showed greater improvement in the Fugl-Meyer Assessment of Upper Extremity scores than Uni-TENS+TOT (mean difference, 2.13; P=0.004), Placebo-TENS+TOT (mean difference, 2.63; P<0.001), and Control groups (mean difference, 3.11; P<0.001) at post-intervention. Both Bi-TENS+TOT (mean difference, 3.39; P<0.001) and Uni-TENS+TOT (mean difference, 1.26; P=0.018) showed significant within-group improvement in the Fugl-Meyer Assessment of Upper Extremity scores. Patients in the Bi-TENS+TOT group showed earlier within-group improvement in the Fugl-Meyer Assessment of Upper Extremity scores at mid-intervention than Uni-TENS+TOT. These improvements were maintained at the 3-month follow-up assessment.

CONCLUSIONS

Bi-TENS combined with TOT is an effective therapy for improving upper limb motor recovery following stroke. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03112473.

Concurrent impact of bilateral multiple joint functional electrical stimulation and treadmill walking on gait and spasticity in post-stroke survivors: a pilot study

Background: Stroke causes multi-joint gait deficits, so a major objective of post-stroke rehabilitation is to regain normal gait function. Design and Setting: A case series completed at a neuroscience institute. Aim: The aim of the study was to determine the concurrent impact of functional electrical stimulation (FES) during treadmill walking on gait speed, knee extensors spasticity and ankle plantar flexors spasticity in post-stroke survivors. Participants: Six post-stroke survivors with altered gait patterns and ankle plantar flexors spasticity (4 = male; age 56.8 ± 4.8 years; Body Mass Index (BMI) 26.2 ± 4.3; since onset of stroke: 30.8 ± 10.4 months; side of hemiplegia [L/R]: 3:3) were recruited. Intervention: Nine treatment sessions using FES bilaterally while walking on a treadmill. Main Outcome Measures: Primary outcome measures included the Modified Modified Ashworth Scale (MMAS), Timed Up and Go test (TUG), 10-m walking test, gait speed, and Functional ambulation category (FAC). Secondary outcome measures included the Step Length Test (SLT), and active range of motion (ROM) of the affected ankle and the knee. Measurements were taken at baseline (T0), at the end of last treatment (T1), and 1 month after the final treatment session (T2). Results: The TUG, 10-m walking test, gait speed, FAC, active ROM, and SLT all significantly improved following treatment (P< .05), while ankle plantar flexors spasticity (P = .135), and knee extensors spasticity (P = .368) did not show any significant decrease. Conclusions: A short duration of bilateral FES in conjugation with treadmill walking contributed to significant improvement in gait speed, functional mobility, functional ambulation, range of motion and step length in post-stroke survivors. In contrast, no significant decreases were identified in the spasticity of the ankle plantar flexors and knee extensors muscles.

Sensory electrical stimulation and postural balance: a comprehensive review

PURPOSE

Sensory electrical stimulation (SES)-i.e., low-intensity electrical currents below, at, or just above the sensory threshold but below the motor threshold-is mainly used to restore/improve postural balance in pathological and healthy subjects. However, the ins and outs of its application as well as the neurophysiological effects induced are not yet well known. Hence, the aim of this paper was to address the effects of SES on postural balance based on these considerations.

METHOD

The immediate/concurrent effects (SES applied during postural balance measurements), the acute effects (SES durably applied before measuring postural balance) and the chronic effects (SES included in training/rehabilitation programs, i.e., measurements performed before and after the programs) were analysed with a comprehensive review.

RESULT

SES can lead to the improvement of postural balance using any of the three applications (immediate/concurrent, acute and chronic), notably in pathological subjects. The beneficial effects of SES can take place at the peripheral (sensory receptors sensitivity), spinal (spinal motoneural excitablity) and supra-spinal (cortex reorganisation or adaptation) levels. In healthy subjects, SES appears interesting, but too few studies have been conducted with this population to report clear results. Moreover, the literature is relatively devoid of comparative studies about the characteristics of the stimulation current (e.g., location, current parameters, duration).

CONCLUSION

In practice, SES appears to be particularly useful to reinforce or restore the postural function in the immediate/concurrent, acute or chronic application in pathlogical populations while its effects should be confirmed in healthy sujects by future studies. Moreover, future research should focus on the different characteristics of stimulation.

Rewiring the Lesioned Brain: Electrical Stimulation for Post-Stroke Motor Restoration

Electrical stimulation has been extensively applied in post-stroke motor restoration, but its treatment mechanisms are not fully understood. Stimulation of neuromotor control system at multiple levels manipulates the corresponding neuronal circuits and results in neuroplasticity changes of stroke survivors. This rewires the lesioned brain and advances functional improvement. This review addresses the therapeutic mechanisms of different stimulation modalities, such as noninvasive brain stimulation, peripheral electrical stimulation, and other emerging techniques. The existing applications, the latest progress, and future directions are discussed. The use of electrical stimulation to facilitate post-stroke motor recovery presents great opportunities in terms of targeted intervention and easy applicability. Further technical improvements and clinical studies are required to reveal the neuromodulatory mechanisms and to enhance rehabilitation therapy efficiency in stroke survivors and people with other movement disorders.

Activation of the primary motor cortex using fully-implanted electrical sciatic nerve stimulation

Functional degradation of the motor cortex usually results from brain injury, stroke, limb amputation, aging or other diseases. Currently, there are no ideal means of treatment, other than medication and sports rehabilitation. The present study investigated whether electrical stimulation of the sciatic nerve can activate the motor-related area of the brain. The study is based on a self-developed fully implantable nerve electrical stimulator and a self-developed multi-channel electroencephalogram (EEG) electrode array. The sciatic nerves of Sprague-Dawley rats (sorted into old and young groups) were stimulated by the electrical stimulator under anesthesia, and the EEG signal was recorded simultaneously. The relationship between sciatic nerve stimulation and brain activity was analyzed. The results showed that when the sciatic nerve was stimulated by the implanted electrical stimulator, motor-related channels were activated, causing contraction of the left leg. It was found that at the frequency band of 8-16 Hz, the EEG signal in the right motor area was higher than at other frequency bands. This phenomenon was identical in both young and old rats. The results indicated that electrical stimulation of the sciatic nerve can activate the motor region of the rat brain, and provided evidence that stimulation of the sciatic nerve could be a method of preventing motor cortex degeneration.