Transcutaneous Vagus Nerve Stimulation Combined with Rehabilitation Training in the Intervention of Upper Limb Movement Disorders After Stroke: A Systematic Review

Analysis of the effect of combined rehabilitation training and transcutaneous vagus nerve electrical stimulation on promoting central nervous system remodeling in stroke patients

OBJECTIVE

To explore the effect of combined rehabilitation training and transcutaneous vagus nerve electrical stimulation (t-VNS) on promoting central nervous system remodeling and neurological function recovery in stroke patients.

METHODS

A total of 124 S patients admitted to our hospital from January to December 2023 were included in this study. The therapeutic effects were evaluated using the Modified Barthel Index (MBI) and the simplified Fugl-Meyer Assessment Scale (sFMA) to measure patients' activities of daily living and motor function recovery. Additionally, neurophysiological assessments, including electromyography (EMG) and motor evoked potentials (MEPs), were conducted to evaluate changes in neuromuscular and central nervous system function. Changes in neural activity in the frontal lobe and motor cortex were assessed through transcutaneous vagus nerve stimulation and electroencephalography. Moreover, all adverse events were recorded.

RESULTS

After treatment, patients in the t-VNS combined with rehabilitation training group showed significant improvements in sFMA and MBI scores compared to the pure rehabilitation training group (P < 0.05). In terms of neurophysiology, patients in the combined treatment group exhibited significant increases in electromyographic activity and MEPs (P < 0.05). EEG results indicated enhanced neuroplasticity of the frontal lobe and motor cortex with t-VNS treatment. The incidence of skin stimulation and ear pain in the combined treatment group was significantly higher than that in the pure rehabilitation training group.

CONCLUSION

Combined rehabilitation training and transcutaneous vagus nerve electrical stimulation have significant effects on neurological function recovery and central nervous system remodeling in stroke patients, effectively improving patients' motor function and activities of daily living.

Applications of transcranial direct current stimulation over vagus nerve on dysphagia after stroke

Vagus nerve stimulation (VNS) has been commonly employed for the functional rehabilitation of stroke patients. This study aimed to investigate the therapeutic effects of transcranial direct current stimulation on the vagus nerve (TDCSVN) in improving dysphagia in stroke patients. Patients experiencing dysphagia following a stroke were diagnosed with dysphagia by a water swallow test. Swallowing function was evaluated with the standard swallowing scale score and the functional dysphagia scale. Serum levels of interleukin (IL)-1β and IL-8 were measured with enzyme-linked immunosorbent assays. TDCSVN treatment resulted in a significantly greater reduction in both the standard swallowing scale and functional dysphagia scale scores compared to conventional treatment. Furthermore, TDCSVN treatment led to a notable increase in hemoglobin and albumin levels, suggesting a more substantial improvement in dysphagia compared to conventional methods. Additionally, TDCSVN treatment was more effective in decreasing serum levels of IL-1β and IL-8 in dysphagic patients after a stroke. TDCSVN treatment demonstrated a significant inhibitory effect on inflammatory cytokines, resulting in a more pronounced improvement in dysphagia among stroke patients.NEW & NOTEWORTHY The present study demonstrates that transcranial direct current stimulation on the vagus nerve (TDCSVN) treatment shows a significant inhibitory effect on the production of inflammatory factors, resulting in a more pronounced improvement in dysphagia among stroke patients.

Acupuncture modulates the gut microbiota in Alzheimer's disease: current evidence, challenges, and future opportunities

Alzheimer's disease, one of the most severe and common neurodegenerative diseases, has no effective cure. Therefore it is crucial to explore novel and effective therapeutic targets. The gut microbiota - brain axis has been found to play a role in Alzheimer's disease by regulating the neuro-immune and endocrine systems. At the same time, acupuncture can modulate the gut microbiota and may impact the course of Alzheimer's disease. In this Review, we discuss recent studies on the role of acupuncture on the gut microbiota as well current challenges and future opportunities of acupuncture as potential treatment for the prevention and treatment of Alzheimer's disease.

Transcutaneous vagus nerve stimulation: a new strategy for Alzheimer's disease intervention through the brain-gut-microbiota axis?

Transcutaneous vagus nerve stimulation (tVNS) is an emerging non-invasive technique designed to stimulate branches of the vagus nerve distributed over the body surface. Studies suggest a correlation between the brain-gut-microbiota (BGM) axis and the pathogenesis of Alzheimer's disease (AD). The BGM axis represents a complex bidirectional communication system, with the vagus nerve being a crucial component. Therefore, non-invasive electrical stimulation of the vagus nerve might have the potential to modify-most of the time probably in a non-physiological way-the signal transmission within the BGM axis, potentially influencing the progression or symptoms of AD. This review explores the interaction between percutaneous vagus nerve stimulation and the BGM axis, emphasizing its potential effects on AD. It examines various aspects, such as specific brain regions, gut microbiota composition, maintenance of intestinal environmental homeostasis, inflammatory responses, brain plasticity, and hypothalamic-pituitary-adrenal (HPA) axis regulation. The review suggests that tVNS could serve as an effective strategy to modulate the BGM axis and potentially intervene in the progression or treatment of Alzheimer's disease in the future.

Application of vagus nerve stimulation on the rehabilitation of upper limb dysfunction after stroke: a systematic review and meta-analysis

Objective

This study aimed to elucidate the efficacy, safety, and long-term implications of vagus nerve stimulation (VNS) as a viable therapeutic option for patients with upper limb dysfunction following a stroke.

Methods

Data from the following libraries were searched from inception to December 2022: PubMed, Wanfang, Scopus, China Science and Technology Journal Database, Embase, Web of Science, China Biology Medicine Disc, Cochrane Library, and China National Knowledge Infrastructure. Outcomes included indicators of upper limb motor function, indicators of prognosis, and indicators of safety (incidence of adverse events [AEs] and serious AEs [SAEs]). Two of the authors extracted the data independently. A third researcher arbitrated when disputes occurred. The quality of each eligible study was evaluated using the Cochrane Risk of Bias tool. Meta-analysis and bias analysis were performed using Stata (version 16.0) and RevMan (version 5.3).

Results

Ten trials (VNS combined with rehabilitation group vs. no or sham VNS combined with rehabilitation group) with 335 patients were included in the meta-analysis. Regarding upper extremity motor function, based on Fugl-Meyer assessment scores, VNS combined with other treatment options had immediate (mean difference [MD] = 2.82, 95% confidence interval [CI] = 1.78-3.91, I² = 62%, p < 0.00001) and long-term (day-30 MD = 4.20, 95% CI = 2.90-5.50, p < 0.00001; day-90 MD = 3.27, 95% CI = 1.67-4.87, p < 0.00001) beneficial effects compared with that of the control treatment. Subgroup analyses showed that transcutaneous VNS (MD = 2.87, 95% CI = 1.78-3.91, I² = 62%, p < 0.00001) may be superior to invasive VNS (MD = 3.56, 95% CI = 1.99-5.13, I² = 77%, p < 0.0001) and that VNS combined with integrated treatment (MD = 2.87, 95% CI = 1.78-3.91, I² = 62%, p < 0.00001) is superior to VNS combined with upper extremity training alone (MD = 2.24, 95% CI = 0.55-3.93, I² = 48%, p = 0.009). Moreover, lower frequency VNS (20 Hz) (MD = 3.39, 95% CI = 2.06-4.73, I² = 65%, p < 0.00001) may be superior to higher frequency VNS (25 Hz or 30 Hz) (MD = 2.29, 95% CI = 0.27-4.32, I² = 58%, p = 0,03). Regarding prognosis, the VNS group outperformed the control group in the activities of daily living (standardized MD = 1.50, 95% CI = 1.10-1.90, I² = 0%, p < 0.00001) and depression reduction. In contrast, quality of life did not improve (p = 0.51). Safety was not significantly different between the experimental and control groups (AE p = 0.25; SAE p = 0.26).

Conclusion

VNS is an effective and safe treatment for upper extremity motor dysfunction after a stroke. For the functional restoration of the upper extremities, noninvasive integrated therapy and lower-frequency VNS may be more effective. In the future, further high-quality studies with larger study populations, more comprehensive indicators, and thorough data are required to advance the clinical application of VNS.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42023399820.