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vagus_nerve_stimulation

Vagus nerve stimulation

It was found that intermittent electrical stimulation from the vagus nerve produces inhibition of neural processes, which can alter brain activity and terminate seizures. This paved way for the concept of vagal nerve stimulator (VNS).

Ogbonnaya and Kaliaperumal described the evolution of the VNS and its use in different fields of medicine. They also reviewed the literature focusing on the mechanism of action of VNS producing desired effects in different conditions. PUBMED and EMBASE search was performed for 'VNS' and its use in refractory seizure management, depression, obesity, memory, and neurogenesis. VNS has been in vogue over for the past three decades and has proven to reduce the intensity and frequency of seizure by 50% in the management of refractory seizures. Apart from this, VNS has been shown to promote neurogenesis in the dentate gyrus of rat hippocampus after 48 hours of stimulation of the vagus nerve. Improvement has also been observed in non-psychotic major depression from a randomized trial conducted 7 years ago. The same concept has been utilized to alter behavior and cognition in rodents, and good improvement has been observed.

Studies have proven that VNS is effective in obesity management in patients with depression. Several hypotheses have been postulated for the mechanism of action of VNS contributing to its success. VNS has gained significant popularity with promising results in epilepsy surgery and treatment-resistant depression. The spectrum of its use has also extended to other fields of medicine including obesity, memory, and neurogenesis, and there is still a viable scope for its utility in the future 1).


Vagus nerve stimulation (VNS) is an established surgical treatment for medically intractable epilepsy with more than 75 000 devices implanted worldwide till 2015.

VNS likely has a positive effect on response inhibition, at least in patients with epilepsy that benefit clinically from the treatment, presumably relating to enhancements of response-inhibition mechanisms and, therefore, identify enhanced response inhibition as a possible cognitive benefit of VNS 2).

Vagus nerve stimulation (VNS) with vagus nerve stimulator delivered during rehabilitative training enhances neuroplasticity and improves recovery in models of cortical ischemic stroke.

Rats were trained to perform an automated, quantitative measure of forelimb function. Once proficient, rats received an intrastriatal injection of bacterial collagenase to induce ICH. Rats then underwent VNS paired with rehabilitative training (VNS+Rehab; n=14) or rehabilitative training without VNS (Rehab; n=12). Rehabilitative training began ≥9 days after ICH and continued for 6 weeks.

VNS paired with rehabilitative training significantly improved recovery of forelimb function when compared with rehabilitative training without VNS. The VNS+Rehab group displayed a 77% recovery of function, whereas the Rehab group only exhibited 29% recovery. Recovery was sustained after cessation of stimulation. Both groups performed similar amounts of trials during rehabilitative, and lesion size was not different between groups.

VNS paired with rehabilitative training confers significantly improved forelimb recovery after intracerebral hemorrhage (ICH) compared to rehabilitative training without VNS 3).

Indications

When resective epilepsy surgery is not possible, vagus nerve stimulation (VNS) can be an option.

Vagus nerve stimulation (VNS) is effective in refractory epilepsy and depression and is being investigated in heart failure, headache, gastric motility disorders and asthma.

see Vagus nerve stimulation for depression.

Epilepsy

Tinnitus

Results suggest that vagus nerve stimulation paired with tones could become an effective therapy for the treatment of tinnitus 4).

Complications

Technical Aspects

The new AspireSR generator offers a unique technical improvement over the previous Demipulse. Whether the highly interesting CBSD feature will provide an additional benefit for the patients, and will rectify the additional costs, respectively, cannot be answered in the short-term. The preoperative handling is straightforward, provided that certain recommendations are taken into consideration. The intraoperative handling is equivalent to former models-except for the placement of the generator, which might cause cosmetic issues and has to be discussed with the patient carefully. We recommend the consideration of the AspireSR in patients with documented ictal tachycardia to provide a substantial number of patients for later seizure outcome analysis 5).

Outcome

1)
Ogbonnaya S, Kaliaperumal C. Vagal nerve stimulator: Evolving trends. J Nat Sci Biol Med. 2013 Jan;4(1):8-13. doi: 10.4103/0976-9668.107254. PubMed PMID: 23633829; PubMed Central PMCID: PMC3633308.
2)
Schevernels H, van Bochove ME, De Taeye L, Bombeke K, Vonck K, Van Roost D, De Herdt V, Santens P, Raedt R, Boehler CN. The effect of vagus nerve stimulation on response inhibition. Epilepsy Behav. 2016 Oct 12;64(Pt A):171-179. doi: 10.1016/j.yebeh.2016.09.014. PubMed PMID: 27743550.
3)
Hays SA, Khodaparast N, Hulsey DR, Ruiz A, Sloan AM, Rennaker RL 2nd, Kilgard MP. Vagus nerve stimulation during rehabilitative training improves functional recovery after intracerebral hemorrhage. Stroke. 2014 Oct;45(10):3097-100. doi: 10.1161/STROKEAHA.114.006654. Epub 2014 Aug 21. PubMed PMID: 25147331; PubMed Central PMCID: PMC4175144.
4)
De Ridder D, Kilgard M, Engineer N, Vanneste S. Placebo-Controlled Vagus Nerve Stimulation Paired with Tones in a Patient with Refractory Tinnitus: A Case Report. Otol Neurotol. 2015 Feb 14. [Epub ahead of print] PubMed PMID: 25689839.
5)
Schneider UC, Bohlmann K, Vajkoczy P, Straub HB. Implantation of a new Vagus Nerve Stimulation (VNS) Therapy® generator, AspireSR®: considerations and recommendations during implantation and replacement surgery-comparison to a traditional system. Acta Neurochir (Wien). 2015 Feb 13. [Epub ahead of print] PubMed PMID: 25673257.
vagus_nerve_stimulation.txt · Last modified: 2018/12/31 11:03 by administrador