Vagal Stimulation Research Articles

Vagus nerve stimulation during training fails to improve learning in healthy rats

Learning new skills requires neuroplasticity. Vagus nerve stimulation (VNS) during sensory and motor events can increase neuroplasticity in networks related to these events and might therefore serve to facilitate learning on sensory and motor tasks. We tested if VNS could broadly improve learning on a wide variety of tasks across different skill domains in healthy, female adult rats. VNS was paired with presentation of stimuli or on successful trials during training, strategies known to facilitate plasticity and improve recovery in models of neurological disorders. VNS failed to improve either rate of learning or performance for any of the tested tasks, which included skilled forelimb motor control, speech sound discrimination, and paired-associates learning. These results contrast recent findings from multiple labs which found VNS pairing during training produced learning enhancements across motor, auditory, and cognitive domains. We speculate that these contrasting results may be explained by key differences in task designs, training timelines and animal handling approaches, and that while VNS may be able to facilitate rapid and early learning processes in healthy subjects, it does not broadly enhance learning for difficult tasks.

Stimulated Vocal Fold Immobility After Vagal Nerve Stimulator Placement: A Case Series.

Vagal nerve stimulator (VNS) implantation is a vital therapy for epilepsy refractory to other treatments; however, it is associated with a very high rate of voice changes. Relatively few of these patients are evaluated for vocal fold motion impairments. In this series, we evaluate 5 such patients with a novel phenotype of forced abduction with VNS stimulation. Retrospective case series. Five patients with a VNS implant who underwent operative direct or in-office rigid laryngoscopy and had vocal fold motion impairment associated with VNS activation are included. All 5 patients had vocal fold mobility with VNS off and a fixed with activation. All patients exhibited vocal fold abduction with VNS activation. Patient 2 has since undergone laryngeal reinnervation, which helped her intermittent dysphonia but left a small glottic gap. A type 1 thyroplasty corrected this gap and improved her voice further. Patient 3 has undergone laryngeal reinnervation for which early results show improvement in perceptual and patient reported outcomes. Patients 4 and 5 have both undergone laryngeal reinnervation with improvement in voice. Previous reported cases of stimulated immobility associated with VNS use describe only adduction of the vocal fold. This series expands the previous work showing the VNS activation can also cause stimulated immobility in an abducted position, for which reinnervation and other medialization procedures offer promising treatment.

Vagus nerve stimulation (VNS) preventing postoperative cognitive dysfunction (POCD): two potential mechanisms in cognitive function.

Postoperative cognitive dysfunction (POCD) impacts a significant number of patients annually, frequently impairing their cognitive abilities and resulting in unfavorable clinical outcomes. Aimed at addressing cognitive impairment, vagus nerve stimulation (VNS) is a therapeutic approach, which was used in many mental disordered diseases, through the modulation of vagus nerve activity. In POCD model, the enhancement of cognition function provided by VNS was shown, demonstrating VNS effect on cognition in POCD. In the present study, we primarily concentrates on elucidating the role of the VNS improving the cognitive function in POCD, via two potential mechanisms: the inflammatory microenvironment and epigenetics. This study provided a theoretical support for the feasibility that VNS can be a potential method to enhance cognition function in POCD.

Role of vagus nerve stimulation in epilepsy

ABSTRACT Introduction and purpose: Epilepsy affects 1% globally, with 2.6 to 6 million cases in Europe. 30-40% of the 50 million epilepsy patients globally don't respond to drugs. For those ineligible for surgery, Vagus Nerve Stimulation (VNS) therapy offers an alternative for drug-resistant epilepsy and major depression. A brief description of the state of knowledge: Vagus Nerve Stimulation (VNS) is a modern therapy using implanted or non-invasive devices to regulate nerve activity with controlled electrical impulses. Vagus Nerve Stimulation (VNS) is effective for focal seizures, including simple partial seizures and auras. It also shows promise in reducing seizures in generalized tonic-clonic seizures and benefits patients with epileptic encephalopathies like Lennox-Gastaut syndrome. VNS effectively decreases both the frequency and duration of seizures in individuals contending with intractable epilepsy. The use of vagus nerve stimulation is generally a safe and well-tolerated form of treatment. VNS therapy improves psychomotor functions in patients with severe drug-resistant epilepsy, showing positive effects on cognitive aspects. The precise mechanism through which VNS affects the body is not fully understood, but it has demonstrated effectiveness, especially in cases of drug-resistant epilepsy. Conclusions: Extensive research backs Vagus Nerve Stimulation (VNS) as an effective palliative for intractable epilepsy, reducing seizures. Yet, identifying specific patients who would benefit most from VNS treatment lacks clear criteria. Neuromodulation remains crucial for healthcare professionals handling drug-resistant epilepsy.

Acute and preventive medical treatment of cluster headache in Taiwan: A narrative review.

Cluster headache (CH) is a debilitating neurological disorder characterized by severe, unilateral pain and ipsilateral autonomic symptoms. Chronic CH is exceedingly rare in Taiwan, constituting approximately 1% of all CH cases. This narrative review provides an up-to-date overview of the acute and preventive treatment strategies for CH in Taiwan, focusing on currently available pharmacological options in the country. The treatment approach for CH in Taiwan involves a stepwise strategy. High-flow oxygen and triptan nasal sprays are the mainstays of acute treatment, providing rapid relief and good tolerability. Transitional treatments, such as oral steroids and suboccipital steroid injections, serve as a crucial bridge between acute and long-term preventive therapies, offering temporary relief while minimizing side effects through a carefully limited duration. For preventive treatment, verapamil is the first-line option, with lithium and topiramate being the second-line alternatives. Among the CGRP monoclonal antibodies, galcanezumab has demonstrated efficacy in the prevention of episodic CH. Preventive treatments are personalized to individual patients, starting with low doses and close monitoring for adverse effects. Neuromodulatory therapies, such as non-invasive vagus nerve stimulation, show promise for chronic and refractory CH but have limited availability in Taiwan. In conclusion, despite the availability of various acute and preventive treatment options, unmet needs in the management of CH in Taiwan remain. In particular, increased awareness and education among healthcare professionals to improve the diagnosis and management of CH in Taiwan should be implemented.

Stress-sensitive neural circuits change the gut microbiome via duodenal glands

Negative psychological states impact immunity by altering the gut microbiome. However, the relationship between brain states and microbiome composition remains unclear. We show that Brunner's glands in the duodenum couple stress-sensitive brain circuits to bacterial homeostasis. Brunner's glands mediated the enrichment of gut Lactobacillus species in response to vagus nerve stimulation. Cell-specific ablation of the glands markedly suppressed Lactobacilli counts and heightened vulnerability to infection. In the forebrain, we mapped a vagally mediated, polysynaptic circuit connecting the central nucleus of the amygdala to Brunner's glands. Chronic stress suppressed central amygdala activity and phenocopied the effects of gland lesions. Conversely, excitation of either the central amygdala or parasympathetic vagal neurons activated Brunner's glands and reversed the effects of stress on the gut microbiome and immunity. The findings revealed a tractable brain-body mechanism linking psychological states to host defense.

Outcomes of surgical resection and vagus nerve stimulation in patients with medically refractory epilepsy and glutamic acid decarboxylase 65 antibody positivity.

Epilepsy associated with high-titer glutamic acid decarboxylase 65 (GAD65) IgG is often refractory to immunotherapies and antiseizure medication. This study sought to determine the efficacy of vagus nerve stimulation (VNS) and surgical resection in patients with drug-resistant epilepsy associated with GAD65-IgG. We retrospectively identified 15 patients with drug-resistant epilepsy and high serum GAD65 antibody titers (>20 nmol·L-1) who underwent VNS implantation (n = 6), surgical resection (n = 7), or both (n = 2). A responder to VNS was defined as someone with a ≥50% reduction in seizure frequency, and a favorable surgical outcome was defined as Engel I-II. Of the eight patients who underwent VNS implantation, three (37.5%) were initially responders, but this was not sustained in two. Of the nine patients who underwent surgical resection, three (33.3%) had a favorable outcome; however, only one patient was seizure-free at last follow-up. Pathology was available in six patients, and only one had evidence of inflammation; this patient had seizure onset 1 year prior to surgery. Favorable seizure outcome correlated with older age at time of resective surgery, with a trend favoring later age of seizure onset. Taken together, surgical resection and VNS implantation may have limited efficacy in this patient population but can be considered in carefully selected cases.

Vagus nerve electroneurogram-based detection of acute kainic acid induced seizures.

Seizures produce autonomic symptoms, mainly sympathetic but also parasympathetic in origin. Within this context, the vagus nerve is a key player as it carries information from the different organs to the brain and vice versa. Hence, exploiting vagal neural traffic for seizure detection might be a promising tool to improve the efficacy of closed-loop Vagus Nerve Stimulation. This study developed a VENG detection algorithm that effectively detects seizures by emphasizing the loss of spontaneous rhythmicity associated with respiration in acute intrahippocampal Kainic Acid rat model. Among 20 induced seizures in six anesthetized rats, 13 were detected (sensitivity: 65%, accuracy: 92.86%), with a mean VENG-detection delay of 25.3 ± 13.5 s after EEG-based seizure onset. Despite variations in detection parameters, 7 out of 20 seizures exhibited no ictal VENG modifications and remained undetected. Statistical analysis highlighted a significant difference in Delta, Theta and Beta band evolution between detected and undetected seizures, in addition to variations in the magnitude of HR changes. Binomial logistic regression analysis confirmed that an increase in delta and theta band activity was associated with a decreased likelihood of seizure detection. This results suggest the possibility of distinct seizure spreading patterns between the two groups which may results in differential activation of the autonomic central network. Despite notable progress, limitations, particularly the absence of respiration recording, underscore areas for future exploration and refinement in closed-loop stimulation strategies for epilepsy management. This study constitutes the initial phase of a longitudinal investigation, which will subsequently involve reproducing these experiments in awake conditions with spontaneous recurrent seizures.

Effect of vagus nerve stimulation (taVNS) on anxiety and sleep disturbances among elderly health care workers in the post COVID-19 pandemic.

Healthcare workers (HCWs) have been significantly impacted by the pandemic. Elderly health care workers carry out a variety of duties at work and have years of clinical expertise. Anxiety and insomnia are among the more commonly encountered problems in senior physicians and other geriatric medical professional populations. The study aims to determine the effect of vagal nerve stimulation on anxiety and sleep disturbances among geriatric medical professionals. 42 participants were enrolled in this study based on the inclusion and exclusion criteria. The participants were divided into two groups using the closed envelope approach, and they took part in therapy sessions lasting 30 minutes, three times per week for a period of four weeks. The Experimental group A received non-invasive transcutaneous auricular vagal nerve stimulation (taVNS) and Control group A received Jacobson's progressive muscle relaxation technique. With a p value of 0.001, taVNS stimulation significantly improved sleep quality and reduced anxiety after 4 weeks. The post-intervention assessment revealed a highly significant improvement in Group A, with a T value of 251 (p < 0.001). The findings suggest that taVNS may be an effective intervention for addressing anxiety and sleep issues in geriatric medical professionals. These results contribute to the exploration of non-invasive strategies to enhance the well-being of healthcare professionals working in demanding environments.

Effects of auricular stimulation on weight- and obesity-related parameters: a systematic review and meta-analysis of randomized controlled clinical trials.

Over the last three decades, the number of randomized controlled trials (RCTs) using stimulation of auricular vagal sensory nerves by means of electrical stimulation, auricular acupuncture, or acupressure to support weight loss has increased markedly. This systematic review focuses on the effects of auricular stimulation (AS) on anthropometric parameters and obesity-related blood chemistry. The following databases were searched until November 2021: MEDLINE (PubMed), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, and Scopus Database. Data collection and analysis were conducted by two reviewers independently. Quality and risk assessment of included studies was performed using the risk of bias tool of the Cochrane Handbook, and the meta-analysis of the effect of the most frequently assessed biomarkers was conducted using the statistical software RevMan. The full texts of 1,274 studies were screened; 22 contained data on obesity-related outcomes, and 15 trials with 1,333 patients were included in the meta-analysis. The overall quality of the included trials was moderate. AS significantly reduced body mass index (BMI) (mean difference (MD) = -0.38 BMI points, 95% CI (-0.55 to -0.22), p < 0.0001), weight (MD = -0.66 kg, 95% CI (-1.12 to -0.20), p = 0.005), waist circumference (MD = -1.44 cm, 95% CI (-2.69 to -0.20), p = 0.02), leptin, insulin, and HOMA insulin resistance compared to controls. No significant reduction was found in body fat, hip circumference, ratio of waist/hip circumference, cholesterol, LDL, triglycerides, adiponectin, ghrelin, and glucose levels. The AS was safe throughout the trials, with only minor adverse reactions. The study results suggest that a reduction of weight and BMI can be achieved by AS in obese patients; however, the size of the effect does not appear to be of clinical relevance. The effects might be underestimated due to active sham trials. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021231885.

Analysis of the use of vagus nerve stimulator in the treatment of epilepsy

Refractory epilepsy poses a significant challenge in neurology due to approximately 30% of patients being resistant to conventional pharmacological treatments. This study investigates the efficacy and safety of vagus nerve stimulation (VNS) as a therapeutic alternative for these patients. The primary objective is to analyze the reduction in seizure frequency and improvements in the quality of life of patients treated with VNS. Additionally, the study aims to identify and categorize the side effects associated with the use of VNS. The methodology adopted included a qualitative bibliographic review covering renowned databases such as Scielo, Google Scholar, specialized scientific journals, academic repositories, and virtual libraries. Inclusion criteria considered studies that directly addressed the use of VNS in the treatment of epilepsy, while exclusion criteria eliminated duplicate and methodologically inadequate publications. Results indicate that VNS is effective in reducing seizures and improving quality of life, despite potential side effects. It is concluded that VNS is a viable and cost-effective therapeutic option for patients with refractory epilepsy, highlighting the need for future research to optimize stimulation parameters and minimize adverse effects.

Transcutaneous auricular vagus nerve stimulation improves gastric motility and visceral hypersensitivity in rodents of functional dyspepsia by balancing duodenal immune response: an experimental study.

Transcutaneous auricular vagus nerve stimulation improves gastric motility and visceral hypersensitivity in rodents of functional dyspepsia by balancing duodenal immune response: an experimental study.

Brainstem neuronal responses to transcutaneous auricular and cervical vagus nerve stimulation in rats.

Transcutaneous auricular vagus nerve stimulation (taVNS) targets subcutaneous axons in the auricular branch of the vagus nerve at the outer ear. Its non-invasive nature makes it a potential treatment for various disorders. taVNS induces neuromodulatory effects within the nucleus of the solitary tract (NTS), and due to its widespread connectivity, the NTS acts as a gateway to elicit neuromodulation in both higher-order brain regions and other brainstem nuclei (e.g. spinal trigeminal nucleus; Sp5). Our objective was to examine stimulation parameters on single-neuron electrophysiological responses in α-chloralose-anaesthetized Sprague-Dawley rats within NTS and Sp5. taVNS was also compared to traditional cervical VNS (cVNS) on single neuronal activation. Specifically, electrophysiological extracellular recordings were evaluated for a range of frequency and intensity parameters (20-250Hz, 0.5-1.0mA). Neurons were classified as positive, negative or non-responders based on increased activity, decreased activity or no response during stimulation, respectively. Frequency-dependent analysis showed that 20 and 100Hz generated the highest proportion of positive responders in NTS and Sp5 with 1.0mA intensities eliciting the greatest magnitude of response. Comparisons between taVNS and cVNS revealed similar parameter-specific activation for caudal NTS neuronal populations; however, individual neurons showed different activation profiles. The latter suggests that cVNS and taVNS send afferent input to NTS via different neuronal pathways. This study demonstrates differential parameter-specific taVNS responses and begins an investigation of the mechanisms responsible for taVNS modulation. Understanding the neuronal pathways responsible for eliciting neuromodulatory effects will enable more tailored taVNS treatments in various clinical disorders. KEY POINTS: Transcutaneous auricular vagus nerve stimulation (taVNS) offers a non-invasive alternative to invasive cervical vagus nerve stimulation (cVNS) by activating vagal afferents in the ear to induce neuromodulation. Our study evaluated taVNS effects on neuronal firing patterns in the nucleus of the solitary tract (NTS) and spinal trigeminal nucleus (Sp5) and found that 20 and 100Hz notably increased neuronal activity during stimulation in both nuclei. Increasing taVNS intensity not only increased the number of neurons responding in Sp5 but also increased the magnitude of response, suggesting a heightened sensitivity to taVNS compared to NTS. Comparisons between cVNS and taVNS revealed similar overall activation but different responses on individual neurons, indicating distinct neural pathways. These results show parameter-specific and nuclei-specific responses to taVNS and confirm that taVNS can elicit responses comparable to cVNS at the neuronal level, but it does so through different neuronal pathways.

National 22-year epilepsy surgery landscape shows increasing open and minimally invasive pediatric epilepsy surgery.

A surgical "treatment gap" in pediatric epilepsy persists despite the demonstrated safety and effectiveness of surgery. For this reason, the national surgical landscape should be investigated such that an updated assessment may more appropriately guide health care efforts. In our retrospective cross-sectional observational study, the National Inpatient Sample (NIS) database was queried for individuals 0 to <18 years of age who had an International Classification of Diseases (ICD) code for drug-resistant epilepsy (DRE). This cohort was then split into a medical group and a surgical group. The former was defined by ICD codes for -DRE without an accompanying surgical code, and the latter was defined by DRE and one of the following epilepsy surgeries: any open surgery; laser interstitial thermal therapy (LITT); vagus nerve stimulation; or responsive neurostimulation (RNS) from 1998 to 2020. Demographic variables of age, gender, race, insurance type, hospital charge, and hospital characteristics were analyzed between surgical options. Continuous variables were analyzed with weight-adjusted quantile regression analysis, and categorical variables were analyzed by weight-adjusted counts with percentages and compared with weight-adjusted chi-square test results. These data indicate an increase in epilepsy surgeries over a 22-year period, primarily due to a statistically significant increase in open surgery and a non-significant increase in minimally invasive techniques, such as LITT and RNS. There are significant differences in age, race, gender, insurance type, median household income, Elixhauser index, hospital setting, and size between the medical and surgical groups, as well as the procedure performed. An increase in open surgery and minimally invasive surgeries (LITT and RNS) account for the overall rise in pediatric epilepsy surgery over the last 22 years. A positive inflection point in open surgery is seen in 2005. Socioeconomic disparities exist between medical and surgical groups. Patient and hospital sociodemographics show significant differences between the procedure performed. Further efforts are required to close the surgical "treatment gap."

Measuring Fidelity of Constraint-Induced Movement Therapy Delivery with Combined Neuromodulation (Transauricular Vagal Nerve Stimulation)

Abstract Date Presented 03/22/24 Assessment of treatment fidelity is essential when complementing effective motor based therapies like CIMT with neuromodulation. This will ensure successful translation to clinical practice and maintain effectiveness of OT interventions. Primary Author and Speaker: Elizabeth Humanitzki Additional Authors and Speakers: Patty Coker-Bolt, Kelly McGloon, Julia Schroeder Brennan Contributing Authors: Annie Cribb, Alyssa Brennan, Philipp Summers, Bashar W. Badran, Mark George, Dorothea Jenkins

Electrical vagus nerve stimulation is a promising approach to reducing pulmonary complications after an esophagectomy: an experimental rodent model.

After esophagectomy, an imbalanced inflammatory response increases the risk of postoperative morbidity. The vagus nerve modulates local and systemic inflammatory responses, but its pulmonary branches are transected during esophagectomy as part of the oncological resection, which may account for the high incidence of postoperative (pulmonary) complications. This study investigated the effect of electrical vagus nerve stimulation (VNS) on lipopolysaccharide (LPS)-induced lung injury in rats. Rats (n = 60) were randomly assigned to a non-vagotomy or cervical vagotomy group, with VNS or without (NOSTIM). There were four non-vagotomy groups: NOSTIM and bilateral VNS with 100, 50, or 10 µA. The four vagotomy groups were NOSTIM and VNS with fixed amplitude (50 µA) bilaterally before (VNS-50-before) or after bilateral vagotomy (VNS-50-after), or unilaterally (left) before ipsilateral vagotomy (VNS-50-unilaterally). LPS was administered intratracheally after surgery. Pulmonary function, pro-inflammatory cytokines in serum, broncho-alveolar lavage fluid (BALF), and histopathological lung injury (LIS) were assessed 180min post-procedure. In non-vagotomized rats, neutrophil influx in BALF following intra-tracheal LPS (mean 30 [± 23]; P = 0.075) and LIS (mean 0.342 [± 0.067]; P = 0.142) were similar after VNS-100, compared with NOSTIM. VNS-50 reduced neutrophil influx (23 [± 19]; P = 0.024) and LIS (0.316 [± 0.093]; P = 0.043). VNS-10 reduced neutrophil influx (15 [± 6]; P = 0.009), while LIS (0.331 [± 0.053]; P = 0.088) was similar. In vagotomized rats, neutrophil influx (52 [± 37]; P = 0.818) and LIS (0.407 [SD ± 0.037]; P = 0.895) in VNS-50-before were similar compared with NOSTIM, as well as in VNS-50-after (neutrophils 30 [± 26]; P = 0.090 and LIS 0.344 [± 0.053]; P = 0.073). In contrast, VNS-50-unilaterally reduced neutrophil influx (26 [± 10]; P = 0.050) and LIS (0.296 [± 0.065]; P = 0.005). Systemic levels of cytokines TNF-α and IL-6 were undetectable in all groups. Pulmonary function was not statistically significantly affected. In conclusion,VNS limited influx of neutrophils in lungs in non-vagotomized rats and may attenuate LIS. Unilateral VNS attenuated lung injury even after ipsilateral vagotomy. This effect was absent for bilateral VNS before and after bilateral vagotomy. It is suggested that the effect of VNS is dependent on (partially) intact vagus nerves and that the level of the vagotomy during esophagectomy may influence postoperative pulmonary outcomes.

The combined effect of transcutaneous electrical nerve stimulation and transcutaneous auricular vagus nerve stimulation on pressure and heat pain thresholds in pain-free subjects: a randomized cross-over trial

BackgroundTranscutaneous electrical nerve stimulation (TENS) is a non-invasive modality that utilizes electrical currents to modulate pain in populations with acute and chronic pain. TENS has been demonstrated to produce hypoalgesic effects in postoperative pain, fibromyalgia, knee osteoarthritis, and healthy subjects. Transcutaneous auricular vagus nerve stimulation (TaVNS) is a non-invasive modality that modulates the vagus nerve by stimulating its auricular branches. The effects of the combination of TENS and TaVNS on producing an analgesic response have not been studied. Considering that TENS and TaVNS both stimulate similar analgesic pathways but through different means of activation, we can hypothesize that a combination of both methods can produce a more pronounced analgesic response. Therefore, the objective of this study is to assess the hypoalgesic effect of a combination of TENS and TaVNS in pain-free subjects.Methods/designThe study will be a simple crossover design conducted at the University of Hartford. Subjects will be recruited from the University of Hartford population via oral communication, digital flyers, and posters on campus. Thirty participants will undergo two sessions in a crossover manner with one week in between. During one session, the participants will receive TENS with active TaVNS and the other session will be a placebo procedure (TENS with placebo TaVNS). The order of these sessions will be randomized. Importantly, the pressure pain threshold (PPT) and heat pain threshold (HPT) assessors will be blinded to the treatment category. For active TaVNS, a frequency of 25 Hz will be applied with a pulse duration of 200 µs. For placebo TaVNS, the intensity will be increased to a sensory level and then decreased to 0 mA. High-frequency TENS of 100 Hz will be applied in both sessions, with a pulse duration of 200 µsec, asymmetrical biphasic square waveform, and intensity of maximal tolerance without pain. TENS and TaVNS will be turned on for 30 min after a baseline measurement of outcomes. TENS and TaVNS will then be turned off, but the electrodes will remain on until completion of post-treatment assessment. Pressure pain threshold, heat pain threshold, blood pressure, oxygen saturation, and heart rate will be tested 4 times: Once pre-intervention, once during intervention, once immediately after the intervention, and once 15 min post-intervention. Statistical analysis of the data obtained will consider a significance level of p < 0.05.DiscussionThis study will provide evidence concerning the combined effects of TENS and TaVNS on pain threshold in pain-free participants. Based on the outcomes, a greater understanding of how TENS and TaVNS, when used in conjunction, can modulate pain pathways.Trial registrationClinicalTrials.gov NCT06361381. Registered on 09 April 2024.

Vagal Stimulation and Body Balance: A New Frontier in Neuroscience and Integrative Health

Vagal Stimulation and Body Balance: A New Frontier in Neuroscience and Integrative Health

Effectiveness of bimodal stimulation of the auditory-somatosensory system in the treatment of tonal tinnitus

Background and objectivesThe dorsal cochlear nucleus (DCN) is the interaction site of auditory and somatosensory system inputs. According to the stochastic resonance theory, hearing loss increases the neural activity of the somatosensory system in the DCN and causes tinnitus. it is possible to modulate this neural hyperactivity by applying random noise through the auditory and somatosensory systems (bimodal stimulation). Therefore, this study aimed to investigate the effectiveness of the bimodal intervention based on the theory of stochastic resonance. MethodsThe study divided 34 participants into unimodal and bimodal groups with 17 subjects in each. The bimodal group received customized acoustic stimulation along with transcutaneous auricular vagus nerve stimulation (tAVNS) and the unimodal group received customized acoustic stimulation along with tAVNS as a sham. The treatment sessions in both groups were 6 sessions and each session lasted for 20 min. The participants were evaluated before, immediately after, and one month after the completion of the intervention sessions, using the Tinnitus Handicap Inventory (THI) questionnaire and the mismatch negativity (MMN) test. ResultsAfter the intervention sessions, the results indicated a statistically significant decrease in THI scores and a significant increase in the MMN amplitude in the bimodal group compared to the unimodal group. No significant changes in MMN latency were observed between the two groups. These changes were stable in the one-month follow-up visit. ConclusionsOur study showed that bimodal stimulation is a better intervention option compared to unimodal stimulation. Bimodal stimulation may be an effective intervention method for some subjects with tinnitus, especially people with hearing loss who have tonal tinnitus.

CM-Pf deep brain stimulation in polyneuromodulation for epilepsy.

Neuromodulation is a viable option for patients with drug-resistant epilepsies. We reviewed the management of patients with two deep brain neurostimulators. In addition, patients implanted with a device targeting the centromedian-parafascicular (CM-Pf) nuclear complex supplements this report to provide an illustrative case to implantation and programming a patient with three active devices. A narrative review using PubMed and Embase identified patients with drug-resistant epilepsy implanted with more than one neurostimulator was performed. Combinations of vagus nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS) were identified. We provide a background of a newly reported case of an adult with a triple implant eventually responding to CM-Pf DBS as the third implant following suboptimal benefit from VNS and RNS. In review of the literature, dual-device therapy is increasing in reports of use with combinations of VNS, RNS, and DBS to treat patients with drug-resistant epilepsy. We review dual-device implants with thalamic DBS device combinations, functional neural networks, and programming patients with dual devices. CM-Pf is a new target for DBS and has shown a variable response in focal epilepsy. We report the unique case of 28-year-old male with drug-resistant focal epilepsy who experienced a 75% seizure reduction with CM-Pf DBS as his third device after suboptimal responses to VNS and RNS. After 9 months, he also experienced seizure freedom from recurrent focal to bilateral tonic-clonic seizures. No medical or surgical complications or safety issues were encountered. We demonstrate safety and feasibility in an adult combining active VNS, RNS, and CM-Pf DBS. Patients with dual-device therapy who experience a suboptimal response to initial device use at optimized settings should not be considered a neuromodulation "failure." Strategies to combine devices require a working knowledge of brain networks.