Implant- and anesthesia-related factors affecting cardiopulmonary threshold intensities for vagus nerve stimulation

2021 ◽  
Author(s):  
Umair Ahmed ◽  
Yao-Chuan Chang ◽  
Maria F Lopez ◽  
Jason Wong ◽  
Timir Datta-Chaudhuri ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Related Factors ◽  
Factors Affecting

scholarly journals Implant- and anesthesia-related factors affecting threshold intensities for vagus nerve stimulation

2021 ◽  
Author(s):  
Umair Ahmed ◽  
Yao-Chuan Chang ◽  
Maria F. Lopez ◽  
Jason Wong ◽  
Timir Datta-Chaudhuri ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Pearson Correlation ◽  
Physiological Responses ◽  
Fiber Types ◽  
Electrode Impedance ◽  
Related Factors ◽  
Factors Affecting

AbstractVagus nerve stimulation (VNS) is used as therapy in epilepsy and depression and is tested as a potential treatment for several chronic disorders. Typically, VNS is delivered at increasing stimulus intensity until a response is observed (threshold intensity). Factors that affect threshold intensities for engagement of different fiber types and concomitant physiological responses have not been studied. We determined neural and physiological responses to increasing stimulus intensities of VNS in anesthetized and awake animals, and examined the effect of implant- and anesthesia-related factors on threshold intensities in a rodent model of VNS. In acute and long-term cervical vagus nerve implants (53 and 14 rats, respectively) VNS was delivered under isoflurane, ketamine-xylazine, or awake at different intensities. Stimulus-evoked compound action potentials (eCAPs) were recorded, elicited physiological responses were registered, including changes heart rate (HR), breathing, and blood pressure (BP), and threshold intensities were determined. The intensity that elicits eCAPs (“neural threshold”) is significantly lower than what elicits a physiological response (“physiological threshold”, PT) (25 μA ±1.8 vs. 70 μA ±5.2, respectively; Mean ±SEM). Changes in BP occur at the lowest stimulus intensities (80 μA ±7), followed by changes in HR (105 μA ±8.4) and finally in breathing (310 μA ±32.5). PT is lower with than without electrode insulation (60 μA ±12, vs. 700 μA ±123). PT and electrode impedance are correlated in long-term (r=0.47; p<0.001) but not in acute implants (r=-0.34; p NS); both PT and impedance increase with implant age (Pearson correlation r=0.44; p<0.001 and r=0.64; p<0.001, respectively). PT is lowest when animals are awake (210 μA ±33; Mean ±SEM), followed by ketamine-xylazine (630 μA ±154), and isoflurane (1075 μA ±131). The sequence of physiological responses with increasing VNS intensity is similar in both anesthetized and awake states. Implant age, electrical impedance and the type of anesthesia affect VNS threshold and should be accounted for when determining stimulation dose.

scholarly journals Vagus Nerve Stimulation Ameliorates Cognitive Impairment and Increased Hippocampal Astrocytes in a Mouse Model of Gulf War Illness

2021 ◽  
Vol 16 ◽  
pp. 263310552110184
Author(s):  
Lavanya Venkatasamy ◽  
Damir Nizamutdinov ◽  
Jaclyn Jenkins ◽  
Lee A Shapiro
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Gulf War ◽  
Gulf War Illness ◽  
Related Factors ◽  
Cytokines And Chemokines ◽  
Age Related ◽  
Hippocampal Astrocytes ◽  
Emotional Deficits

Gulf war illness (GWI), is a chronic multi-symptom illness that has impacted approximately one-third of the veterans who served in the 1990 to 1991 Gulf War. GWI symptoms include cognitive impairments (eg, memory and concentration problems), headaches, migraines, fatigue, gastrointestinal and respiratory issues, as well as emotional deficits. The exposure to neurological chemicals such as the anti-nerve gas drug, pyridostigmine bromide (PB), and the insecticide permethrin (PER), may contribute to the etiologically related factors of GWI. Various studies utilizing mouse models of GWI have reported the interplay of these chemical agents in increasing neuroinflammation and cognitive dysfunction. Astrocytes are involved in the secretion of neuroinflammatory cytokines and chemokines in pathological conditions and have been implicated in GWI symptomology. We hypothesized that exposure to PB and PER causes lasting changes to hippocampal astrocytes, concurrent with chronic cognitive deficits that can be reversed by cervical vagus nerve stimulation (VNS). GWI was induced in CD1 mice by injecting the mixture of PER (200 mg/kg) and PB (2 mg/kg), i.p. for 10 consecutive days. VNS stimulators were implanted at 33 weeks after GWI induction. The results show age-related cognitive alterations at approximately 9 months after exposure to PB and PER. The results also showed an increased number of GFAP-labeled astrocytes in the hippocampus and dentate gyrus that was ameliorated by VNS.

scholarly journals Factors Affecting Vagus Nerve Stimulation Outcomes in Epilepsy

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Mehdi Abbasi ◽  
Atie Moghtadaie ◽  
Seyed Amir Miratashi Yazdi
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Mri Findings ◽  
Medical Treatments ◽  
Factors Affecting ◽  
Factors Associated ◽  
Surgical History ◽  
And Gender ◽  
Antiepileptic Medications

Epilepsy as a common neurological disease is mostly managed effectively with antiepileptic medications. One-third of patients do not respond to medical treatments requiring alternative therapies. Vagus nerve stimulation (VNS) has been used in the last decades for the treatment of medically resistant epilepsy. Despite the extensive use of VNS in these patients, factors associated with clinical outcomes of VNS remain to be elucidated. In this study, we evaluated factors affecting VNS outcomes in epileptic patients to have a better understanding of patients who are better candidates for VNS therapy. Several databases including PubMed, Scopus, and Google Scholar were searched through June 2020 for relevant articles. The following factors were assessed in this review: previous surgical history, age at implantation and gender, types of epilepsy, duration of epilepsy, age at epilepsy onset, frequency of attacks, antiepileptic drugs, VNS parameters, EEG findings, MRI findings, and biomarkers. Literature data show that nonresponder rates range between 25% and 65%. Given the complexity and diversity of factors associated with response to VNS, more clinical studies are needed to establish better paradigm for selection of patients for VNS therapy.

Effect of Transcutaneous Vagus Nerve Stimulation in Dysphagia After Lateral Medullary Infarction: A Case Report

2019 ◽  
Vol 28 (4) ◽  
pp. 1381-1387
Author(s):  
Ying Yuan ◽  
Jie Wang ◽  
Dongyu Wu ◽  
Dahua Zhang ◽  
Weiqun Song
Keyword(s):  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Rating Scale ◽  
Tube Feeding ◽  
Nasogastric Feeding ◽  
Lateral Medullary Infarction ◽  
Severe Dysphagia ◽  
Transcutaneous Vagus Nerve Stimulation ◽  
Medullary Infarction

Purpose Severe dysphagia with weak pharyngeal peristalsis after dorsal lateral medullary infarction (LMI) requires long-term tube feeding. However, no study is currently available on therapeutic effectiveness in severe dysphagia caused by nuclear damage of vagus nerve after dorsal LMI. The purpose of the present investigation was to explore the potential of transcutaneous vagus nerve stimulation (tVNS) to improve severe dysphagia with weak pharyngeal peristalsis after dorsal LMI. Method We assessed the efficacy of 6-week tVNS in a 28-year-old woman presented with persisting severe dysphagia after dorsal LMI who had been on nasogastric feeding for 6 months. tVNS was applied for 20 min twice a day, 5 days a week, for 6 weeks. The outcome measures included saliva spitted, Swallow Function Scoring System, Functional Oral Intake Scale, Clinical Assessment of Dysphagia With Wallenberg Syndrome, Yale Pharyngeal Residue Severity Rating Scale, and upper esophagus X-ray examination. Results After tVNS, the patient was advanced to a full oral diet without head rotation or spitting. No saliva residue was found in the valleculae and pyriform sinuses. Contrast medium freely passed through the upper esophageal sphincter. Conclusion Our findings suggest that tVNS might provide a useful means for recovery of severe dysphagia with weak pharyngeal peristalsis after dorsal LMI. Supplemental Material https://doi.org/10.23641/asha.9755438

Vagus nerve stimulation in rheumatoid arthritis – Authors' reply

2021 ◽  
Vol 3 (1) ◽  
pp. e14-e15
Author(s):  
Mark C Genovese ◽  
Yaakov A Levine ◽  
David Chernoff
Keyword(s):  
Rheumatoid Arthritis ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation

Cognition-enhancing effect of vagus nerve stimulation on refractory epilepsy secondary to lissencephaly: A case report.

2018 ◽  
Vol 11 (1) ◽  
pp. 80-85
Author(s):  
Rodrigo Marmo da Costa e Souza ◽  
Felipe Ricardo Pereira Vasconcelos De Arruda ◽  
Jose Anderson Galdino Santos ◽  
Jamerson De Carvalho Andrade ◽  
Suellen Mary Marinho Dos Santos Andrade ◽  
...  
Keyword(s):  
Case Report ◽  
Vagus Nerve ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Refractory Epilepsy ◽  
Enhancing Effect

Implanted vagus nerve stimulation in 126 patients: surgical technique and complications

2020 ◽  
Vol 99 (7) ◽  
Keyword(s):  
Vagus Nerve ◽  
Vocal Cord ◽  
Nerve Stimulation ◽  
Vagus Nerve Stimulation ◽  
Pulse Generator ◽  
Operative Procedure ◽  
Intractable Epilepsy ◽  
Vagal Nerve ◽  
University Hospital ◽  
Nerve Stimulator

Introduction: Vagus nerve stimulation is a palliative treatment for patients with refractory epilepsy to reduce the frequency and intensity of seizures. A bipolar helical electrode is placed around the left vagus nerve at the cervical level and is connected to the pulse generator placed in a subcutaneous pocket, most commonly in the subclavian region. Methods: Between March 1998 and October 2019, we performed 196 procedures related to the vagal nerve stimulation at the Neurosurgery Department in Motol University Hospital. Of these, 126 patients were vagal nerve stimulator implantation surgeries for intractable epilepsy. The cases included 69 female and 57 male patients with mean age at the time of the implantation surgery 22±12.4 years (range 2.1−58.4 years). Results: Nine patients (7.1%) were afflicted by complications related to implantation. Surgical complications included postoperative infection in 1.6%, VNS-associated arrhythmias in 1.6%, jugular vein bleeding in 0.8% and vocal cord paresis in 2.4%. One patient with vocal cord palsy also suffered from severe dysphagia. One patient (0.8%) did not tolerate extra stimulation with magnet due to a prolonged spasm in his throat. The extra added benefit of vagus stimulation in one patient was a significant reduction of previously regular severe headaches. Conclusion: Vagus nerve stimulation is an appropriate treatment for patients with drug-resistant epilepsy who are not candidates for focal resective surgery. Implantation of the vagus nerve stimulator is a relatively safe operative procedure.

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