1 Clinical Policy Title: Vagus nerve stimulation Clinical Policy Number: 09.02.01 Effective Date: September 1, 2013 Initial Review Date: May 15, 2013 Most Recent Review Date: April 10, 2018 Next Review Date: April 2019 Related policies: CP# 09.03.01 Laser thermal ablation for epileptic seizures CP# 07.02.02 Phrenic (diaphragmatic) nerve stimulation ABOUT THIS POLICY: Prestige Health Choice has developed clinical policies to assist with making coverage determinations. Prestige Health Choice’s clinical policies are based on guidelines from established industry sources, such as the Centers for Medicare & Medicaid Services (CMS), state regulatory agencies, the American Medical Association (AMA), medical specialty professional societies, and peer-reviewed professional literature. These clinical policies, along with other sources, such as plan benefits and state and federal laws and regulatory requirements, including any state- or plan-specific definition of “medically necessary,” and the specific facts of the particular situation are considered by Prestige Health Choice when making coverage determinations. In the event of conflict between this clinical policy and plan benefits and/or state or federal laws and/or regulatory requirements, the plan benefits and/or state and federal laws and/or regulatory requirements shall control. Prestige Health Choice’s clinical policies are for informational purposes only and not intended as medical advice or to direct treatment. Physicians and other health care providers are solely responsible for the treatment decisions for their patients. Prestige Health Choice’s clinical policies are reflective of evidence- based medicine at the time of review. As medical science evolves, Prestige Health Choice will update its clinical policies as necessary. Prestige Health Choice’s clinical policies are not guarantees of payment. Coverage policy Prestige Health Choice considers the use of vagus nerve stimulation (VNS) to be clinically proven and, therefore, medically necessary when the following criteria are met (Boon, 2018; Englot, 2011; Food and Drug Administration [FDA], 2017; Hayes, 2015): Patient criteria include all of the following: The individual is age 4 years or older. The individual is diagnosed with severe generalized epilepsy with atonic or tonic-clonic seizures. The individual experiences partial onset seizures that are refractory to anti-epileptic (AED) medication therapy, including individuals who are allergic to or suffer debilitating side effects of AEDs. Any one of the following is true: The individual has declined intracranial surgery. The individual has failed other surgical intervention. The individual is not a candidate for surgical resection. Policy contains: Seizure. Medically refractory seizures. Vagus nerve.
16
Embed
Vagus nerve stimulation - Prestige Health Choice · o A NeuroCybernetic Prosthesis® (NCP) vagus nerve stimulation system is contraindicated for individuals with a history of left
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
1
Clinical Policy Title: Vagus nerve stimulation
Clinical Policy Number: 09.02.01
Effective Date: September 1, 2013
Initial Review Date: May 15, 2013
Most Recent Review Date: April 10, 2018
Next Review Date: April 2019
Related policies:
CP# 09.03.01 Laser thermal ablation for epileptic seizures
ABOUT THIS POLICY: Prestige Health Choice has developed clinical policies to assist with making coverage determinations. Prestige Health Choice’s clinical policies are based on guidelines from established industry sources, such as the Centers for Medicare & Medicaid Services (CMS), state regulatory agencies, the American Medical Association (AMA), medical specialty professional societies, and peer-reviewed professional literature. These clinical policies, along with other sources, such as plan benefits and state and federal laws and regulatory requirements, including any state- or plan-specific definition of “medically necessary,” and the specific facts of the particular situation are considered by Prestige Health Choice when making coverage determinations. In the event of conflict between this clinical policy and plan benefits and/or state or federal laws and/or regulatory requirements, the plan benefits and/or state and federal laws and/or regulatory requirements shall control. Prestige Health Choice’s clinical policies are for informational purposes only and not intended as medical advice or to direct treatment. Physicians and other health care providers are solely responsible for the treatment decisions for their patients. Prestige Health Choice’s clinical policies are reflective of evidence-based medicine at the time of review. As medical science evolves, Prestige Health Choice will update its clinical policies as necessary. Prestige Health Choice’s clinical policies are not guarantees of payment.
Coverage policy
Prestige Health Choice considers the use of vagus nerve stimulation (VNS) to be clinically proven and,
therefore, medically necessary when the following criteria are met (Boon, 2018; Englot, 2011; Food and
Drug Administration [FDA], 2017; Hayes, 2015):
Patient criteria include all of the following:
The individual is age 4 years or older.
The individual is diagnosed with severe generalized epilepsy with atonic or tonic-clonic seizures.
The individual experiences partial onset seizures that are refractory to anti-epileptic (AED) medication therapy, including
individuals who are allergic to or suffer debilitating side effects of AEDs.
Any one of the following is true:
The individual has declined intracranial surgery.
The individual has failed other surgical intervention.
The individual is not a candidate for surgical resection.
Policy contains:
Seizure.
Medically refractory seizures.
Vagus nerve.
2
Limitations:
Coverage determinations are subject to benefit limitations and exclusions as delineated by the state
Medicaid authority. The Florida Medicaid website may be accessed at
http://ahca.myflorida.com/Medicaid/.
All other uses of vagus nerve stimulation are not medically necessary. In addition:
Individuals with a progressive disorder, such as malignant brain neoplasm or a progressive
metabolic or degenerative disorder, should not receive vagus nerve stimulation.
The U.S. Food and Drug Administration (FDA) states:
o A NeuroCybernetic Prosthesis® (NCP) vagus nerve stimulation system is contraindicated
for individuals with a history of left or bilateral cervical vagotomy.
o The VNS Therapy System (Cyberonics, Inc., Houston, Texas) device is approved for
individuals of age 4 years and older. It cannot be used after a bilateral or left cervical
vagotomy.
o Individuals with an implanted vagus nerve stimulation device should not have any type of
diathermy (shortwave, microwave, or therapeutic ultrasound), regardless of whether the
device is switched on or off. Diathermy can cause energy to be concentrated into or
reflected by the device, leading to heating and tissue damage, or can damage the device.
Diagnostic ultrasound is not contraindicated.
Transmitter adjustments usually occur in an outpatient setting.
Alternative covered services:
Pharmacotherapy with anticonvulsant medications.
Desensitization of nerve receptors.
Background
The vagus nerve is a paired cranial nerve that originates in the brainstem and ends in the abdominal region.
It carries both somatic and visceral afferent and efferent signals. The majority of its fibers are visceral
afferents with widespread distribution. VNS works on the basis that the vagal visceral afferents provide a
diffuse central nervous system projection. The activation of the diffuse pathways affects neural excitability.
Although the exact mechanism of vagus nerve stimulation on neuronal excitability is not fully defined, it is
known to activate well-defined reflexes and evoke potentials from the cerebellum, cerebral cortex,
hippocampus, and thalamus. Vagus nerve stimulation has been used with success for individuals with
epilepsy.
A vagus nerve stimulation system is composed of an electrode array, an implantable generator, and an
external programming device. The programming device is used to make adjustments and changes to the
stimulation settings, which are transmitted to the implanted generator. The vagus nerve stimulation
generator must be surgically implanted in the upper-left area of the chest, or under the left arm. The left
Prestige Health Choice searched PubMed and the databases of:
5
UK National Health Services Centre for Reviews and Dissemination.
Agency for Healthcare Research and Quality’s National Guideline Clearinghouse and other
evidence-based practice centers.
The Centers for Medicare & Medicaid Services (CMS).
We conducted searches on March 2, 2018. Search terms were: "vagus nerve stimulation" [MeSH].
We included:
Systematic reviews, which pool results from multiple studies to achieve larger sample sizes and
greater precision of effect estimation than in smaller primary studies. Systematic reviews use
predetermined transparent methods to minimize bias, effectively treating the review as a
scientific endeavor, and are thus rated highest in evidence-grading hierarchies.
Guidelines based on systematic reviews.
Economic analyses, such as cost-effectiveness, and benefit or utility studies (but not simple
cost studies), reporting both costs and outcomes — sometimes referred to as efficiency studies,
— which also rank near the top of evidence hierarchies.
Findings
There is evidence that vagus nerve stimulation can reduce seizure frequency, with 14 percent to 79 percent
of patients experiencing at least a 50 percent mean reduction; however, a portion of this treatment benefit
can be attributed to a placebo response (Hayes, 2015). The treatment benefit is maintained for up to 13
years. Adults and children age >12 years seem to benefit equally from the treatment. Most studies to date
have included patients with a broad range of epilepsy syndromes associated with intractable partial
seizures classified as simple, complex, or secondarily generalized.
Some evidence was available specifically investigating vagus nerve stimulation for generalized seizures and
other epileptic syndromes. While the results from these studies suggest that vagus nerve stimulation
therapy may also be effective for these types of seizures, the quality of the evidence was poor, and none of
the studies was sufficiently powered to estimate the treatment benefit and to draw conclusions regarding
seizure type and responsiveness to vagus nerve stimulation. The results of these initial studies will need to
be confirmed in RCTs before any definitive conclusions can be drawn.
Data from nonrandomized controlled trials suggest that vagus nerve stimulation may effectively treat
epilepsy in other patient populations, including those with brain tumors and post-traumatic epilepsy.
However, the quality of these studies is poor and additional data from RCTs are necessary to determine
whether vagus nerve stimulation is better than alternative treatments for these populations.
Several nonrandomized controlled studies have compared the effectiveness of vagus nerve stimulation with
other interventions, including intracranial surgery. Evidence suggests that vagus nerve stimulation may be
more effective in some cases, although the quality of the studies was poor and additional data from RCTs
are needed.
6
A number of studies have evaluated the effect of vagus nerve stimulation on QOL, mood, and cognition in
patients with epileptic syndromes. The results showed that vagus nerve stimulation may improve these
outcomes in some patients, but the specific number and type of improvements were inconsistent among
studies. While vagus nerve stimulation improved QOL in several studies, in others, especially in studies with
very small sample size, improvements were not significant or were noted in only one or two domains;
however, insufficient power to detect a significant effect makes interpretation of these results difficult.
Safety data for vagus nerve stimulation are available for up to 11 years. The most common complications
associated with vagus nerve stimulation therapy were voice alterations, hoarseness, cough, pain, dyspnea,
infection, paresthesia, headache, and pharyngitis. These problems were generally mild, occurred only
during stimulation, and decreased over time or could be resolved by changing device parameters. In some
cases, the NCP had to be repositioned or removed, due to infection or device malfunction, but in most
cases the device was successfully exchanged or reimplanted. A study that compared the incidence of
definite/probable seizure with the expected baseline rate for epilepsy revealed no increased risk of
mortality that could be attributed to the use of vagus nerve stimulation devices. Preliminary evidence
suggests that patients with generalized and other types of seizures may experience similar complications
and are not at a higher risk for negative side effects than patients with partial seizures.
There is currently insufficient evidence to suggest that effectiveness may vary by patient characteristics.
Characteristics that may predict vagus nerve stimulation success include the age at epilepsy onset, the age
at vagus nerve stimulation implantation, the duration of epilepsy before vagus nerve stimulation
implantation, predominant seizure types, and whether a patient has had previous intracranial surgery.
Preliminary data from studies of poor quality suggest that young children (age ≤12 years) and older adults
(age >50 years) are likely to benefit at least as much from vagus nerve stimulation as other populations.
Furthermore, there is evidence that shorter durations of epilepsy before implantation predict better
success. Evidence is conflicting with regard to age at epilepsy onset. Some evidence suggests that a history
of previous intracranial surgery does not predict success of vagus nerve stimulation treatment. Concrete
predictors of a treatment response have not been established, and additional research is required to
substantiate these preliminary findings.
Based on a review of abstracts of published literature (Hayes, 2016), there is insufficient evidence to inform
evidence-based decisions regarding the AspireSR Model 106 by Cyberonics. In small clinical studies, the
device appears to perform as expected by delivering an electrical stimulation in response to the detected
increase in heart rate, which may herald a pending seizure. Duration and frequency of seizures were
decreased in patients who received automatically delivered stimulation. The AutoStim mode eliminates the
need for patient and caregiver interaction with the device, unlike the magnet mode of previous iterations.
Larger studies with long-term clinical outcomes are needed to determine the reliability, safety, and
consistency of this novel device.
There is insufficient evidence to conclude that vagus nerve stimulation improves depression, QOL, and
function in patients with major depressive disorder (MDD) and bipolar disorder. The best level of evidence
(Hayes, 2015) was derived from one 12-week, double-blind, randomized controlled study. There was a
7
statistically significant difference in only one secondary outcome measure. The results of a study comparing
vagus nerve stimulation plus standard treatment with standard treatment alone were also conflicting.
While the primary data analysis suggested that vagus nerve stimulation plus standard treatment was
superior to standard treatment alone, there was significant heterogeneity among patients, and if the
analysis were adjusted to account for these differences, significance was lost. The results from the long-
term uncontrolled studies suggest that patients who respond to the treatment at three or 12 months are
likely to maintain the response for up to 24 months. However, long-term studies lowered the threshold for
the definition of responders; therefore, actual long-term response rates might be lower. Furthermore, a
large, randomized, dose-finding study failed to demonstrate a dose response relationship for vagus nerve
stimulation therapy. Vagus nerve stimulation is associated with severe complications and therefore the risk-
benefit ratio does not favor the use of vagus nerve stimulation therapy for TRD.
A low-quality body of evidence from three clinical reports (n=28 to 294) assessed the net health benefit of
the Maestro Rechargeable System for controlling obesity. One fair-quality double-blind RCT (n=294)
compared active and sham treatment with the Maestro device for ≥ 9 hours daily (Hayes, 2016). A second
fair-quality double-blind RCT (n=239) compared active and sham treatment with the Maestro device for ≥12
hours daily. A prospective case series of very poor quality (n=28) involved treatment of obese patients with
type 2 diabetes with the Maestro device for 12 to 15 (mean, 14) hours daily.
The overall quality of the evidence was assessed taking into consideration the quality of individual studies;
the precision, directness, and consistency of data; and the applicability of the data to general practice.
Overall, the body of evidence is insufficient to draw conclusions about the efficacy of the Maestro device in
that two RCTs failed to reach pre-specified co-primary weight loss endpoints. Comparison and synthesis of
results are limited because the studies used slightly different treatment protocols; used different
definitions for primary outcome measures; and because one used an inert sham device whereas the other
reported delivery of a very low level of electrical charge via the sham implant to the vagus nerve. The
investigators reported that this may have confounded the study results. Importantly, neither RCT had
sufficient follow-up length to determine the long-term durability of device-induced weight loss or the safety
of prolonged device use.
Policy updates:
A systematic review (Cimpianu, 2017) examined invasive and noninvasive vagus nerve stimulation as
treatment for treatment-refractory depression, dementia, schizophrenia, somatoform disorder, and other
psychiatric disorders and found the efficacy of vagus nerve stimulation in affective disorders to be
promising, but noted there is a need for more controlled and naturalistic studies in this regard. In other
conditions like schizophrenia, Alzheimer's disease, obsessive-compulsive disorder (OCD), Parkinson’s
disease (PD), post-traumatic stress disorder (PTSD), and fibromyalgia, there were either no effects or
preliminary data on efficacy was inconclusive with regard to the efficacy of vagus nerve stimulation.
In 2018, the policy was updated as follows. Six peer-reviewed publications and an FDA Summary of Safety
and Effectiveness Data document were added to the reference list. Four of the peer-reviewed publications
and the Summary of Safety and Effectiveness Data were added to the summary of clinical evidence. The
8
reference for one guideline was updated. The FDA released a Summary of Safety and Effectiveness Data
expanding the indicated ages to include ages 4 – 11, for use of the VNS Therapy System as an adjunctive
therapy in reducing the frequency of seizures in those with partial onset seizures that are refractory to
antiepileptic medications (FDA, 2017). The coverage policy has been revised to reflect this expansion.
In two systematic reviews, vagus nerve stimulation was found to be effective for epilepsy among adults
(Boon, 2018) and in Dravet syndrome, a rare pediatric condition marked by epileptic activity among other
symptoms (Dibué-Adjei, 2017). A third meta-analysis found that vagus nerve stimulation in children with
epilepsy is less effective among those with intellectual disabilities (Sourbron, 2017). Two previous studies
have found vagus nerve stimulation to be cost-effective in pediatric patients (Helmers, 2012; Majoie, 2001).
A Cochrane review found a lack of studies comparing approaches to epilepsy treatment including vagus
nerve stimulation, intracranial stimulation, “best medical practice,” or surgery (Sprengers, 2017). Vagus
nerve stimulation was found to be associated with higher rates of sleep apnea in meta-analysis, suggesting
the need to take measures of sleeping behaviors at presentation and during follow-up (Romero-Osorio,
2018).
Summary of clinical evidence:
Citation Content, Methods, Recommendations
Boon (2018)
Neurostimulation for
drug-resistant
epilepsy
Key points:
This systematic review found moderate-quality evidence for the efficacy of vagus nerve
stimulation in adults with drug-resistant partial epilepsies.
Romero-Osorio
(2018)
Changes in sleep
patterns after vagus
nerve stimulation,
deep brain
stimulation or
epilepsy surgery
Key points:
This systematic review of 36 studies found that vagus nerve stimulation causes sleep apnea,
dependent of the stimulation variables. However, modifying these settings can revert the
condition.
Measures of sleep parameters should be included during the initial evaluation and follow-up
of those considered for invasive procedures for epilepsy control, especially with vagus nerve
stimulation due to the risk of sleep apnea. High-quality, comparative studies of various types
of nerve stimulation are needed.
Cimpianu (2017)
Vagus nerve
stimulation in
psychiatry: A
systematic review of
the available
evidence
Key points:
Systematic review of vagus nerve stimulation as treatment for treatment-refractory
depression, dementia, schizophrenia, somatoform disorder, and other psychiatric disorders.
Found the efficacy of vagus nerve stimulation in affective disorders to be promising, but
noted there is a need for more controlled and naturalistic studies.
For schizophrenia, Alzheimer's disease, OCD, PD, PTSD, and fibromyalgia, either no effects
or preliminary data on efficacy was inconclusive with regard to the efficacy of vagus nerve
stimulation.
Dibué-Adjei (2017)
Efficacy of adjunctive
vagus nerve
Key points:
Dravet syndrome is a rare pediatric disease marked by severe epileptic encephalopathy with
intractable seizures, recurrent status epilepticus and cognitive decline. This meta-analysis
9
Citation Content, Methods, Recommendations
stimulation in
patients with Dravet
syndrome: A meta-
analysis of 68
patients
included 13 studies comprising 68 patients.
Over half (52.9%) of patients experienced more than 50% reduction of seizures. The
average seizure reduction was 50.8%, but this could only be assessed in 28 patients.
Several studies (seven of 13 studies) reported additional treatment benefits; however, these
could not be assessed systematically due to limitations in the data.
Among those with Dravet syndrome, vagus nerve stimulation appears to reduce seizure
frequency. The authors suggest that controlled trials of VNS in this rare condition using
patient-centric outcome measures are indicated.
FDA (2017)
Summary of safety
and effectiveness
data (SSED). VNS
Therapy System.
Key points:
This supplement expands the indication.
Sourbron (2017)
Vagus nerve
stimulation in
children: A focus on
intellectual disability
Key points:
This meta-analysis examined the findings of seven studies that analyzed vagus nerve stimulation for children with epilepsy, among children with and without intellectual disabilities.
This analysis found that vagus nerve stimulation was less effective at treating pediatric epilepsy among children with intellectual disabilities than it was among those without intellectual disabilities (Mantel-Haenszel meta-analysis; p = 0.028, odds ratio 0.18, 95%, confidence interval 95% 0.039, 0.84). Improvement in QOL was demonstrated in numerous studies. The most frequent adverse events reported were transient and well tolerated. No side effects were reported on cognition and behavior.
The authors state that the results suggest that vagus nerve stimulation should be considered early on in the treatment of this subgroup. Numerous sources of bias include a preponderance of retrospective studies, differences in follow-up, lack of control arms, heterogeneous series, and a limited number of participants.
Sprengers (2017)
Deep brain and
cortical stimulation
for epilepsy
Key points:
No trials comparing intracranial stimulation to “best medical practice,” surgery, or vagus nerve stimulation have been published.
Hayes (2016)
AspireSR Model 106
(Cyberonics) for
vagus nerve
stimulation
Key points:
Insufficient evidence exists regarding the AspireSR Model 106 vagus nerve stimulation by
Cyberonics.
In small clinical studies, the device appears to perform as expected in patients who received
automatically delivered stimulation.
Larger outcome studies are needed.
Hayes (2016)
Maestro
Rechargeable
System
(EnteroMedics Inc.)
for vagal blocking for
Key points:
Insufficient evidence exists regarding the Maestro Rechargeable System for controlling
obesity:
o One fair-quality double-blind RCT (n=294) compared active and sham treatment with
the Maestro device for ≥9 hours daily.
o A second fair-quality double-blind RCT (n=239) compared active and sham treatment
10
Citation Content, Methods, Recommendations
obesity control with the Maestro device for ≥12 hours daily.
o A very-poor-quality prospective case series (n=28) involved treatment of obese patients
with type 2 diabetes with the Maestro device for 12 to 15 (mean, 14) hours daily.
Hayes (2016)
Vagus nerve
stimulation for
depression
Key points:
There have been no studies to date that have demonstrated improved health outcomes with
the use of vagus nerve stimulation when compared to other treatment modalities for
depression.
A systematic review with 235 participants revealed no statistical differences between the
control and the placebo groups, citing insufficient data to confirm that vagus nerve
stimulation was or was not effective in the treatment of depression.
The APA practice guideline for the treatment of major depressive disorders states that
electroconvulsive therapy remains the best established efficacy above other stimulation
therapies.
Hayes (2015)
Vagus nerve
stimulation for
epilepsy
Key points:
Vagus nerve stimulation can reduce seizure frequency, with 14 percent to 79 percent of
patients experiencing at least a 50 percent mean reduction.
A portion of this treatment benefit can be attributed to a placebo response.
The treatment benefit is maintained for up to 13 years.
Indicated for intractable partial seizures classified as simple, complex, or secondarily
generalized.
References
Professional society guidelines/other:
Fisher R, Handforth A. Reassessment: VNS for epilepsy: a report of the Therapeutics and Technology
Assessment Subcommittee of the American Academy of Neurology (AAN). Neurology. 1999; 53:666–9. Re-
affirmed October 17, 2003.
Gelenberg AJ, Freeman MP, Markowitz JC, et al. American Psychiatric Association (APA). Practice guideline
for the treatment of patients with major depressive disorder. Third edition. October 2010; reaffirmed
October 2015. https://guidelines.gov/summaries/summary/24158?. Accessed March 14, 2018.
Hayes Inc., Hayes Health Clinical Research Response. AspireSR Model 106 (Cyberonics) for Vagus Nerve
Stimulation. Lansdale, Pa. Hayes Inc.; February 2016.
Hayes Inc., Hayes Health Medical Technology Report. Vagus Nerve Stimulation for Epilepsy. Lansdale, Pa.
Hayes Inc.; May 2015.
Hayes Inc., Hayes Health Technology Brief. Maestro Rechargeable System (EnteroMedics Inc.) for Vagal
Blocking for Obesity Control. Lansdale, Pa. Hayes Inc.; February 2016.
Cimpianu CL, Strube W, Falkai P, Palm U, Hasan A. Vagus nerve stimulation in psychiatry: a systematic
review of the available evidence. J Neural Transm (Vienna). 2017;124(1):145-158.
Daban C, Martinez-Aran A, Cruz N, Vieta E. Safety and efficacy of vagus nerve stimulation in treatment-
resistant depression. A systematic review. J Affect Disord. 2008; 110(1-2):1-15.
Dibué-Adjei M, Fischer I, Steiger HJ, Kamp MA. Efficacy of adjunctive vagus nerve stimulation in patients with Dravet syndrome: A meta-analysis of 68 patients. Seizure. 2017;50:147-152.
Englot DJ, Chang EF, Auguste KI. Vagus nerve stimulation for epilepsy: a meta-analysis of efficacy and
predictors of response. J Neurosurg. 2011; 115(6):1248-55. (a)
Englot DJ, Chang EF, Auguste KI. Efficacy of vagus nerve stimulation for epilepsy by patient age, epilepsy
duration, and seizure type. Neurosurg Clin N Am. 2011; 22(4):443-8, v. (b)
Gaynes BN, Lux L, Lloyd S, Hansen RA, Gartlehner G, Thieda P, et al. Nonpharmacologic Interventions for
Treatment-Resistant Depression in Adults. Comparative Effectiveness Review No. 33. (Prepared by RTI
International-University of North Carolina (RTI-UNC) Evidence based Practice Center under Contract No.
290-02-0016I.) AHRQ Publication No. 11-EHC056-EF. Rockville, MD: Agency for Healthcare Research and
Quality. April 2016 Update. https://ahrq-ehc-application.s3.amazonaws.com/media/files/treatment-
resistant-depression_surveillance.pdf. Accessed March 2, 2018.
George MS, Aston-Jones G. Noninvasive techniques for probing neurocircuitry and treating illness: vagus
nerve stimulation (VNS), transcranial magnetic stimulation (TMS) and transcranial direct current stimulation
Martin JL, Martin-Sanchez E. Systematic review and meta-analysis of vagus nerve stimulation in the
treatment of depression: variable results based on study designs. Eur Psychiatry. 2012; 27(3):147-55.
Montavont A, Demarquay G, Ryvlin P, et al. Long-term efficiency of vagus nerve stimulation (VNS) in non-
surgical refractory epilepsies in adolescents and adults [article in French]. Rev Neurol (Paris). 2007;
163(12):1169-77.
Osoegawa C, Gomes JS, Grigolon RB, et al. Non-invasive brain stimulation for negative symptoms in schizophrenia: An updated systematic review and meta-analysis. Schizophr Res. 2018.
Romero-Osorio O, Gil-Tamayo S, Narino D, Rosselli D. Changes in sleep patterns after vagus nerve
stimulation, deep brain stimulation or epilepsy surgery: Systematic review of the literature. Seizure.
2018;56:4-8.
Rush AJ, Marangell LB, Sackeim HA, et al. Vagus nerve stimulation for treatment-resistant depression: a