Curr Opin Biomed Eng. 2024 Dec;32:100557. doi: 10.1016/j.cobme.2024.100557. Epub 2024 Aug 24.

ABSTRACT

Computational models of electrical stimulation, block and recording of autonomic nerves enable analysis of mechanisms of action underlying neural responses and design of optimized stimulation parameters. We reviewed advances in computational modeling of autonomic nerve stimulation, block, and recording over the past five years, with a focus on vagus nerve stimulation, including both implanted and less invasive approaches. Few models achieved quantitative validation, but integrated computational pipelines increase the reproducibility, reusability, and accessibility of computational modeling. Model-based optimization enabled design of electrode geometries and stimulation parameters for selective activation (across fiber locations or types). Growing efforts link models of neural activity to downstream physiological responses to represent more directly the therapeutic effects and side effects of stimulation. Thus, computational modeling is an increasingly important tool for analysis and design of bioelectronic therapies.

PMID:39650310 | PMC:PMC11619812 | DOI:10.1016/j.cobme.2024.100557

Acta Neurol Belg. 2024 Dec 9. doi: 10.1007/s13760-024-02691-x. Online ahead of print.

ABSTRACT

Traumatic brain injury (TBI) is a leading cause of death and disability throughout the world. Despite significant advances in medical care, many TBI survivors continue to have cognitive, physical, and psychological deficits that have a significant impact on their quality of life. Neuromodulation techniques, which use electrical or magnetic stimulation to modulate brain activity, have shown promise in the treatment of TBI symptoms. The purpose of this narrative review is to provide an overview of the current state of neuromodulation techniques for TBI, such as transcranial magnetic stimulation, transcranial direct current stimulation, deep brain stimulation, and vagus nerve stimulation. This review summarizes the evidence for using these techniques, as well as their potential mechanisms of action and limitations. Additionally, the review discusses future research directions in this field, as well as the possibility of combining neuromodulation techniques with other interventions to improve outcomes for TBI patients.

PMID:39652157 | DOI:10.1007/s13760-024-02691-x

Neuroscience. 2024 Dec 5:S0306-4522(24)00705-X. doi: 10.1016/j.neuroscience.2024.12.004. Online ahead of print.

ABSTRACT

In the last years, there has been a growing interest in the brain-heart connection. A core aspect of this connection appears to be the autonomic nervous system, particularly through the vagus nerve. Accordingly, vagally mediated heart rate variability (vmHRV) is currently considered as an index of top-down control processes involved in cognition and emotion regulation. Recent evidence indicates that higher vmHRV is associated with enhanced cognitive performance across multiple domains, such as executive functions, memory, attention, and language skills. From this premises, this study examined the relationship between cardiac vagal tone, as indicated by heart rate variability (vmHRV), and cognitive functions. A sample of 143 healthy young adults completed a comprehensive neuropsychological battery. The results revealed a strong correlation between resting vmHRV and cognitive functions, particularly in executive processes. Participants with higher resting vagal tone showed superior cognitive performance in tasks requiring cognitive control, motor and cognitive inhibition, cognitive flexibility, and working memory in comparison to those with lower resting vagal tone. Furthermore, vagal-mediated heart rate variability was also found to be associated with memory, attention, and executive performance. The current research provides new insights into the interactions between cognitive and autonomic systems, further supporting evidence for body-brain interactions.

PMID:39645073 | DOI:10.1016/j.neuroscience.2024.12.004

Br J Anaesth. 2024 Dec 6:S0007-0912(24)00683-4. doi: 10.1016/j.bja.2024.10.035. Online ahead of print.

NO ABSTRACT

PMID:39645517 | DOI:10.1016/j.bja.2024.10.035

Adv Sci (Weinh). 2024 Dec 6:e2412361. doi: 10.1002/advs.202412361. Online ahead of print.

ABSTRACT

Implantable peripheral nerve electrodes are crucial for monitoring health and alleviating symptoms of chronic diseases. Advanced compliant electrodes have been developed because of their biomechanical compatibility. However, these mechanically tissue-like electrodes suffer from unmanageable operating forces, leading to high risks of nerve injury and fragile electrode-tissue interfaces. Here, a peripheral nerve electrode is developed that simultaneously fulfills the criteria of body temperature softening and tissue-like modulus (less than 0.8 MPa at 37 °C) after implantation. The central core is altered from the tri-arm crosslinker to the star-branched monomer to kill two birds (close the translation temperature to 37 °C and decrease the modulus after implantation) with one stone. Furthermore, the decreased interfacial impedance (325.1 ± 46.9 Ω at 1 kHz) and increased charge storage capacity (111.2 ± 5.8 mC cm^-2) are achieved by an in situ electrografted conductive polymer on the strain-insensitive conductive network of Au nanotubes. The electrodes are readily wrapped around nerves and applied for long-term stimulation in vivo with minimal inflammation. Neuromodulation experiments demonstrate their potential clinical utility, including vagus nerve stimulation in rats to suppress seizures and alleviation of cardiac remodeling in a canine model of myocardial infarction.

PMID:39639850 | DOI:10.1002/advs.202412361

Brain Behav. 2024 Dec;14(12):e70176. doi: 10.1002/brb3.70176.

ABSTRACT

BACKGROUND: The effect of vagus nerve stimulation (VNS) on cognitive domain of attention and executive functions (AEFs) has not been extensively researched. This study was set up to investigate performance variability on cognitive tests assessing AEFs in drug-resistant epilepsy (DRE) patients receiving VNS therapy during a follow-up of up to 5 years.

METHODS: Thirty-three DRE patients were assessed with the interference, maze, and written verbal fluency tests as a part of EpiTrack screening before and after VNS implantation through repeated follow-ups according to the clinical VNS protocol. A linear mixed-effects model was used to analyse changes in test scores.

RESULTS: Maze performance improved significantly by an average of 0.20 s per month (95% confidence interval (CI): -0.365 to -0.041; p = 0.014). Interference performance improved by an average of 0.05 s per month (p = 0.207) and number of words increased by an average of 0.03 words per month (p = 0.079) on the verbal fluency test. On the maze test, patients with psychiatric comorbidities improved the most (0.52 s/month, p = 0.001), while on the interference test, patients with frontal lobe epilepsy (FLE), those taking 1-2 antiseizure medications (ASMs) and patients with focal to bilateral tonic-clonic seizures improved the most (0.14 s/month, p = 0.005; 0.14 s/month, p = 0.033 and 0.16 s/month, p = 0.087, respectively). For verbal fluency, no clinically meaningful improvement was noted in any of the groups.

CONCLUSION: During the follow-up, maze performance markedly improved, while performance on the interference and verbal fluency tasks remained relatively stable at the group level. Accordingly, visual anticipation and planning improved during VNS therapy whereas response inhibition was unchanged at the group level despite significant enhancements in patients with FLE and those taking 1-2 ASM. Furthermore, the presence of psychiatric comorbidities correlated with even greater improvement on maze performance.

PMID:39643448 | DOI:10.1002/brb3.70176

Chin Med J (Engl). 2024 Dec 5. doi: 10.1097/CM9.0000000000003404. Online ahead of print.

NO ABSTRACT

PMID:39632585 | DOI:10.1097/CM9.0000000000003404

Exp Neurol. 2024 Dec 3:115094. doi: 10.1016/j.expneurol.2024.115094. Online ahead of print.

ABSTRACT

Stroke induces cardiac dysfunction, which increases poststroke mortality and morbidity. An imbalance in the autonomic nervous system resulting from brain injury may serve as the underlying mechanism. The present study investigated whether transcutaneous auricular vagus nerve stimulation (taVNS) attenuates poststroke cardiac dysfunction by activating the parasympathetic nervous system. Adult male mice were subjected to transient middle cerebral artery occlusion (MCAO) and reperfusion surgery. The mice in the treatment group received repeated taVNS starting 60 min after the onset of cerebral ischemia. To assess whether the effects of taVNS were associated with parasympathetic activity, the MCAO mice in the atropine group received intraperitoneal injections of atropine to inhibit parasympathetic activity prior to taVNS. taVNS significantly increased the left ventricular ejection fraction (EF), attenuated myocardial apoptosis, reduced myocardial hypertrophy, and reduced fibrosis following stroke. The beneficial effects of taVNS on cardiac dysfunction were abolished by atropine administration. Heart rate variability (HRV) analysis and western blot analysis revealed that taVNS increased parasympathetic activity but decreased sympathetic dominance in mice with MCAO. Furthermore, the cardioprotective effects of taVNS were associated with muscarinic acetylcholine receptor activation, PI3K-Akt pathway modulation, and eNOS regulation in the heart. Therefore, taVNS alleviates cardiac dysfunction after stroke and is associated with activation of the parasympathetic nervous system.

PMID:39637965 | DOI:10.1016/j.expneurol.2024.115094

NPJ Parkinsons Dis. 2024 Dec 5;10(1):231. doi: 10.1038/s41531-024-00844-6.

ABSTRACT

The vagus nerve (VN) is the main neural pathway linking the gut and brain in Parkinson’s disease (PD). In this study, we utilized high-resolution ultrasound to measure the VN cross-sectional area (CSA) in 96 healthy controls (HCs) and 75 PD patients. The PD group was further categorized into three subgroups: PD-preRBD, PD-postRBD, and PD-nonRBD. PD-preRBD was the body-first subtype, and PD-postRBD and PD-nonRBD were the brain-first subtype. The PD group had a significantly lower VN CSA than HCs. Subgroup analysis revealed that the PD-preRBD group tended to exhibit a smaller VN CSA than both the PD-postRBD and PD-nonRBD groups. The VN CSA, specifically the right VN, was significantly correlated with the body-first subtype and some components of PD-related assessment scales. Overall, these findings provide evidence of VN atrophy in PD, especially in body-first PD, suggesting that VN ultrasound could serve as an adjunctive diagnostic tool.

PMID:39639003 | PMC:PMC11621687 | DOI:10.1038/s41531-024-00844-6

Trials. 2024 Dec 5;25(1):812. doi: 10.1186/s13063-024-08658-w.

ABSTRACT

BACKGROUND: Depersonalization-derealization disorder (DPD) is a complex psychiatric condition marked by profound and often relentless feelings of detachment from one’s self and surroundings. Transcranial electrical stimulation (taVNS) holds promise as a potential therapeutic approach for DPD. This study aims to investigate the safety and efficacy of taVNS in treating DPD.

METHODS: DPD patients were recruited as research subjects and randomly allocated to the experimental and control groups, with the former receiving active-taVNS treatment and the latter receiving sham stimulation treatment for 6 weeks. The efficacy of taVNS in treating DPD was evaluated by comparing scores for DPD symptoms, depression and anxiety symptoms, cognitive function, and social function before and after treatment between the two groups. The safety of taVNS in treating DPD was assessed by comparing general safety assessment results between the two groups of DPD patients.

DISCUSSION: This study will assess taVNS as a potential treatment for DPD, evaluating its safety, efficacy, and impact on patient outcomes and societal burden.

TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2300078183, Registered on 30 November, 2023, https://www.chictr.org.cn/showproj.html?proj=206119.

PMID:39639403 | DOI:10.1186/s13063-024-08658-w