J Family Med Prim Care. 2024 Oct;13(10):4217-4224. doi: 10.4103/jfmpc.jfmpc_153_24. Epub 2024 Oct 18.

ABSTRACT

BACKGROUND: Dental care of patients with epilepsy and seizures must be performed by dentists who are familiar with these disorders. Improper training and incapability to manage medical emergencies, including epileptic seizures, may cause thoughtful consequences and legal actions. Therefore, dental students must have a proper knowledge of the disease and its consequences. They should have the ability to provide first-aid measures helping a patient experiencing an epileptic seizure in their clinics. This study aims to evaluate the first-aid knowledge and practices towards patients with epileptic seizures among the dental students in Saudi Arabia.

METHODS: A cross-sectional study was conducted targeting dental students in Saudi Arabia from 15 September 2022 to 15 December 2022 using convenience sampling. An online questionnaire was sent to the students via social media platforms for data collection. The data analysis was conducted using the Statistical Package for the Social Sciences (SPSS) version 16.0.

RESULTS: Of the 499 dental students included, 154 (30.86%) students had ever seen an epileptic patient in the clinics. About 16% of students did not know about performing cardiopulmonary resuscitation (CPR) on patients. The majority (66.5%) would call the ambulance after the patient’s seizure stops. About 82% of students prefer to call an ambulance if the patients face difficulty breathing or waking up after the seizure. More than 60% of students were taking precautions before treating an epilepsy patient. About 58.5% of the students were using local anaesthesia for an epilepsy patient. Nearly 41.9% do not have the confidence to treat an epilepsy patient. About 28.0% would swipe the vagus nerve stimulation (VNS) magnet over the left side of the chest. Of 154 students, who had ever seen epileptic patients, the majority (68.8%) refused to treat patients if they observe noncompliance with medication and follow-up among the patients who had any recent illness or seizures (16.2%).

CONCLUSION: The undergraduate dental students had an intermediate knowledge regarding epilepsy and epileptic seizure first aid. However, some students lacked the confidence to deal with the epileptic cases in their clinics. Educational campaigns on epilepsy and first-aid courses targeting dental students are highly recommended.

PMID:39629417 | PMC:PMC11610869 | DOI:10.4103/jfmpc.jfmpc_153_24

No Shinkei Geka. 2024 Nov;52(6):1206-1214. doi: 10.11477/mf.1436205037.

ABSTRACT

The kidney and brain share strain vessels, which are short and small arterioles that branch out of larger arteries. These vessels are vulnerable to risk factors such as atherosclerosis, old age, hypertension, diabetes, dyslipidemia, and smoking. The nervous system and the kidneys interact to maintain homeostasis. Many chronic kidney disease(CKD)-specific and nonspecific factors contribute to structural and functional cerebral changes in patients with CKD. In contrast, vagus nerve stimulation has been reported to alleviate inflammatory diseases, including kidney disease. Several new drugs have recently become available for the treatment of CKD: sodium-glucose co-transporter-2 inhibitors for CKD; finerenone, a mineralocorticoid receptor antagonist for CKD with type 2 diabetes; and a hypoxia-inducible factor prolyl-hydroxylase inhibitor for anemia in patients with CKD.

PMID:39622326 | DOI:10.11477/mf.1436205037

J Affect Disord. 2024 Nov 28;372:96-105. doi: 10.1016/j.jad.2024.11.077. Online ahead of print.

ABSTRACT

BACKGROUND: Invasive vagus nerve stimulation (iVNS) is approved for the treatment of major depressive disorder (MDD). The limited understanding of its underlying mechanisms, however, hinders stratification and the prediction of treatment response. Given the strong projections of the afferent vagal nucleus to brain regions involved in emotional processing, we tested whether acute transauricular VNS (taVNS) can improve emotional processing that is a core deficit in MDD.

METHODS: We performed a randomized controlled trial. The facial emotion recognition task was performed by 52 participants with MDD and 44 controls during taVNS and sham stimulation. Linear mixed-effect models were used to evaluate the effect of taVNS.

RESULTS: At baseline, we found a negative bias across all participants with lower accuracy in detecting positive facial expressions (F(1, 173) = 17.39, p < 0.001) and more misclassification towards negative facial expressions (F(1, 173) = 13.73, p < 0.001). Acute taVNS improved the accuracy of detecting positive facial expressions across all participants (F(1, 90.26) = 6.49, p = 0.013), both at low and high intensity. Moreover, fewer negative emotional states as quantified by visual analogue scales were reported during taVNS (F(1, 85) = 5.34, p = 0.023). The effect of taVNS on ratings of positive emotional states was group-dependent (F(1, 86) = 4.20, p = 0.044), as only controls reported less positive emotions (t = 2.06, p = 0.042).

CONCLUSION: Independent of diagnosis acute taVNS has an impact on emotional processing. Future studies need to explore whether these acute effects can serve as a predictive marker for the long-term impact of taVNS.

PMID:39615758 | DOI:10.1016/j.jad.2024.11.077

Psychophysiology. 2024 Nov 30:e14735. doi: 10.1111/psyp.14735. Online ahead of print.

ABSTRACT

Interoception, the perception of visceral sensations, is key for several survival functions, including those related to feeding behavior. Sensations of hunger and satiety are mediated by gastric signals transmitted via the vagus nerve to the Nucleus of Solitary Tract. Transcutaneous auricular vagus nerve stimulation (taVNS) has been shown to modulate brain-viscera communication and to impact interoceptive processing in the cardiac domain. Yet, its effect on gastric interoception remains unclear. The aim of this study was to investigate taVNS’ modulatory effects on gastric interoception using the Water Load Test-II (WLT-II) and its impact on food-related dispositions through a disposition and willingness to eat task (DWET). Participants underwent active or sham taVNS while performing the WLT-II and DWET. Results showed no significant difference in gastric interoceptive accuracy and amount of water ingested between taVNS groups. However, we found a significant reduction in food liking after the fullness phase of the WLT-II in the active (vs sham) taVNS group, suggesting an influence of vagal activation in the inhibition of food enjoyment when satiated. These findings suggest that, while taVNS may not directly enhance gastric interoceptive accuracy at a conscious level, it influences food-related dispositions, likely by modulating the processing of gastric signals. Further research exploring the intricate relationship between vagal modulation, interoceptive abilities and eating behaviors is warranted to elucidate the underlying mechanisms and, possibly, develop targeted interventions for eating disorders.

PMID:39614658 | DOI:10.1111/psyp.14735

Neuroscience. 2024 Nov 28;565:117-123. doi: 10.1016/j.neuroscience.2024.11.065. Online ahead of print.

ABSTRACT

Vagus nerve stimulation (VNS) has garnered significant attention as a promising bioelectronic therapy. In recent years, respiratory-gated auricular vagal afferent nerve stimulation (RAVANS), a novel non-invasive vagus nerve stimulation technique, has emerged. RAVANS integrates respiration with transcutaneous auricular vagus nerve stimulation (taVNS) and shares a similar mechanism of action to traditional VNS. Similar to conventional Vagus Nerve Stimulation (VNS), RAVANS may mitigate brain injury through three primary pathways: reducing neuronal apoptosis, modulating neurotransmitter release, and influencing inflammatory factor pathways. In this paper, we emphasize how RAVANS enhances the activation of nucleus of the solitary tract （NTS）and the locus coeruleus by regulating the monoaminergic and GABA systems through respiratory control. Additionally, it leverages the beneficial effects of respiration on the central nervous system. In this review, we delineate the potential mechanisms of action of RAVANS, provide a comprehensive overview of its clinical applications in chronic low back pain, migraine, depression, hypertension, and cognitive disorders. Furthermore, we offer future perspectives on optimizing the parameters of RAVANS and its application in post-stroke dysphagia. This will pave the way for new avenues in RAVANS research.

PMID:39615649 | DOI:10.1016/j.neuroscience.2024.11.065

Front Neurol. 2024 Nov 14;15:1465764. doi: 10.3389/fneur.2024.1465764. eCollection 2024.

ABSTRACT

INTRODUCTION: Pairing vagus nerve stimulation with traditional rehabilitation therapies results in improved motor recovery in people with stroke. However, this approach has not yet been studied in people with spinal cord injury (SCI). Motor recovery continues to be challenging after SCI, and there is a need for innovative research strategies to enhance motor recovery after SCI. Hence, this pilot randomized controlled trial aims to evaluate the safety, feasibility, and potential efficacy of pairing vagus nerve stimulation (VNS) with rehabilitation therapy to restore the motor function of the paretic upper limbs in people with cervical SCI.

METHODS AND ANALYSIS: In this triple-blind, randomized, sham-controlled pilot study, 8 adults with chronic incomplete SCI will be implanted with a VNS device and randomly assigned to either active VNS (0.8 mA) control VNS (0.0 mA) paired with upper limb rehabilitation. Each participant will undergo 18 in-clinic therapy sessions over 6 weeks, each lasting 120 min and delivered three times per week. Following the in-clinic phase, participants will continue with a 90-day home exercise program. Participants in both groups will receive similar goal-directed and intense upper limb rehabilitation. The therapy is focused on active movements, task specificity, high number repetitions, variable practice, and active participant engagement. Post-treatment assessment will occur immediately after in-clinic therapy and at 30 and 90 days of follow-up. After completion of blinding at 90 days follow-up, participants in the control group will be offered 6 weeks of in-clinic active VNS (0.8 mA) paired with rehabilitation. The safety of pairing VNS with rehabilitation will be assessed by the occurrence of adverse events in each group, and feasibility by the number of treatment sessions and follow-up visits attended and the number of dropouts. Potential efficacy will be assessed by measuring the change in Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) performance from baseline to immediately after in-clinic therapy and to 90 days. Secondary clinical outcome measures are the Toronto Rehabilitation Institute Hand Function Test, Capabilities of Upper Extremity Questionnaire, Spinal Cord Injury Independence Measure-III self-care subscore, and Spinal Cord Injury-Quality of Life scale.

ETHICS AND DISSEMINATION: The trial protocol was approved by the Institutional Review Board of UTHealth (HSC-MS-22-0579). We anticipate publishing the results in a peer-reviewed journal within 1 year of study completion.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT05601661.

PMID:39610700 | PMC:PMC11604078 | DOI:10.3389/fneur.2024.1465764

mSphere. 2024 Nov 29:e0086324. doi: 10.1128/msphere.00863-24. Online ahead of print.

ABSTRACT

Inhalation of prions into the nasal cavity is an efficient route of infection. Following inhalation of infectious prions, animals develop disease with a similar incubation period compared with per os exposure, but with greater efficiency. To identify the reason for this increased efficiency, we identified neural structures that uniquely innervate the nasal cavity and neural structures known to mediate neuroinvasion following oral infection and used immunohistochemistry to determine the temporal and spatial accumulation of prions from hamster tissue sections containing cell bodies and axons at 2-week intervals following prion exposure. Prions were identified in the trigeminal ganglion, the spinal trigeminal tract in the brainstem, the intermediolateral cell column of the thoracic spinal cord, and the dorsal motor nucleus of the vagus/solitary nucleus complex months prior to detection of prions in the olfactory bulb or superior cervical ganglion. These results indicate that the trigeminal nerve, but not the olfactory nerve or sympathetic nerves, are involved in neuroinvasion following inhalation of prions into the nasal cavity. The detection of prions in the intermediolateral cell column of the thoracic spinal cord and dorsal motor nucleus of the vagus nerve 14 weeks following inhalation is consistent with inoculum crossing the alimentary wall and infecting the enteric nervous system via this route of infection. Neuroinvasion via the trigeminal nerve, in combination with entry into the central nervous system via autonomic innervation of the enteric nervous system, may contribute to increased efficiency of nasal cavity exposure to prions compared with per os exposure in hamsters.IMPORTANCEInhalation of prions into the nasal cavity is thought to be a route of infection in naturally acquired prion diseases. Experimental studies indicate that inhalation of prions is up to two orders of magnitude more efficient compared with ingestion. The mechanisms underlying this observation are poorly understood. We found a previously unreported direct route of neuroinvasion from the nasal cavity to the nervous system. Importantly, the peripheral ganglia involved may be a useful tissue to sample for prion diagnostics. Overall, identification of a new route of neuroinvasion following prion infection may provide an anatomical basis to explain the increased efficiency of infection following prion inhalation.

PMID:39611853 | DOI:10.1128/msphere.00863-24

Clin Neurophysiol. 2024 Nov 26;169:47-52. doi: 10.1016/j.clinph.2024.11.012. Online ahead of print.

ABSTRACT

OBJECTIVE: The mechanisms of actions of transcutaneous auricular vagus nerve stimulation (taVNS) are still unclear, however the activity of the cholinergic system seems to be critical for the induction of VNS-mediated plasticity. Transcranial Magnetic Stimulation (TMS) is a well-suited, non-invasive tool to investigate cortical microcircuits involving different neurotransmitters. Herein, we evaluated the effect of taVNS on short-latency afferent inhibition (SAI), a TMS paradigm specifically measuring cholinergic neurotransmission.

METHODS: Fifteen healthy subjects participated in this randomized placebo-controlled double-blind study. Each subject underwent two different sessions of 1-hour exposure to taVNS (real and sham) separated by a minimum of 48 h. Real taVNS was administered at left external acoustic meatus, while sham stimulation was performed at left ear lobe. We evaluated SAI bilaterally over the motor cortex before and after exposure to taVNS.

RESULTS: No side effects were reported by any of the participants. Statistical analysis did not show any significant effect of taVNS on SAI.

CONCLUSIONS: Our study demonstrated that cholinergic circuits explored by SAI are different from circuits engaged by taVNS.

SIGNIFICANCE: Since the influence of VNS on cholinergic neurotransmission has been exhaustively demonstrated in animal models, further studies are mandatory to understand the actual impact of VNS on cholinergic circuits in humans.

PMID:39612592 | DOI:10.1016/j.clinph.2024.11.012

Nat Rev Gastroenterol Hepatol. 2024 Nov 29. doi: 10.1038/s41575-024-01028-6. Online ahead of print.

NO ABSTRACT

PMID:39613861 | DOI:10.1038/s41575-024-01028-6

Mol Brain. 2024 Nov 27;17(1):86. doi: 10.1186/s13041-024-01162-x.

ABSTRACT

Depression, a prevalent neuropsychiatric disorder, involves the dysregulation of neurotransmitters such as dopamine (DA). The restoration of DA balance is a pivotal therapeutic target for this condition. Recent studies have indicated that both antidepressant medications and non-pharmacological treatments, such as transcutaneous auricular vagus nerve stimulation (taVNS), can promote recovery from depressive symptoms. Despite the promise of taVNS as a non-invasive depression therapy, its precise mechanism remains unclear. We hypothesized that taVNS exerts antidepressant effects by modulating the DAergic system. To investigate this, we conducted experiments demonstrating that taVNS in anesthetized mice reduced depressive-like behaviors. However, this effect was abolished when DA neurons in the ventral tegmental area (VTA^DA) were inhibited. Additionally, taVNS in anesthetized mice enhanced VTA^DA activity, providing further evidence to support its antidepressant effects. Overall, our findings suggest that taVNS alleviates depression by augmenting VTA^DA activity, thereby contributing to a more comprehensive understanding of its therapeutic mechanisms.

PMID:39604984 | PMC:PMC11600629 | DOI:10.1186/s13041-024-01162-x