// Evidence Grader
Claim grades, A through F
Every major claim in this course gets a transparent grade. Use this dashboard to audit what's established, what's preliminary, and what's hype.
A
Clinically established
B
Supported, context-specific
C
Promising, preliminary
D
Plausible, unproven
E
Popular, weak support
F
Misleading or false
A
VNS reduces seizures in some drug-resistant epilepsy patients
Established adjunctive therapy (FDA, AAN guideline).
Module 01 · Why the Vagus Nerve Matters
A
VNS is FDA-approved for treatment-resistant depression
PMA-approved adjunctive long-term treatment.
Module 01 · Why the Vagus Nerve Matters
B
Slow breathing increases vagally mediated HRV
Supported, but not equivalent to device VNS.
Module 01 · Why the Vagus Nerve Matters
F
taVNS cures inflammation
Human evidence is inconsistent across conditions.
Module 01 · Why the Vagus Nerve Matters
F
HRV is a perfect measure of vagal tone
HRV is context-dependent and influenced by many factors.
Module 01 · Why the Vagus Nerve Matters
E
Cold exposure 'resets' the vagus nerve
Marketing claim exceeding evidence; modest autonomic shifts only.
Module 01 · Why the Vagus Nerve Matters
A
The vagus nerve exits the skull via the jugular foramen
Anatomical fact.
Module 02 · Anatomy of the Vagus Nerve
F
All vagal fibers are parasympathetic
~80% are afferent sensory fibers.
Module 02 · Anatomy of the Vagus Nerve
A
The auricular branch supplies cutaneous innervation to part of the external ear
Cymba conchae and parts of the external auditory canal — basis for taVNS.
Module 02 · Anatomy of the Vagus Nerve
F
The left and right cervical vagi have identical organ-targeting
Asymmetric cardiac innervation; left RLN takes a longer thoracic loop.
Module 02 · Anatomy of the Vagus Nerve
B
Cervical vagal fibers are organized in functionally specific fascicles
Supported by recent mapping; clinical translation underway.
Module 02 · Anatomy of the Vagus Nerve
B
HRV reflects autonomic activity
Supported but multifactorial.
Module 03 · Autonomic Nervous System & 'Vagal Tone'
B
RMSSD and HF-HRV are reasonable proxies of vagally mediated heart-rate modulation
Established with caveats.
Module 03 · Autonomic Nervous System & 'Vagal Tone'
F
HRV directly measures vagus nerve firing
Indirect, context-dependent.
Module 03 · Autonomic Nervous System & 'Vagal Tone'
E
LF/HF ratio cleanly indexes sympathovagal balance
Widely used historically, but methodologically contested.
Module 03 · Autonomic Nervous System & 'Vagal Tone'
F
A single low-HRV morning reading is diagnostic
Trend over weeks is the only defensible use.
Module 03 · Autonomic Nervous System & 'Vagal Tone'
A
Vagal afferents project to NTS
Established neuroanatomy.
Module 04 · Vagus Physiology: Afferents, Efferents, Reflexes
F
All vagus stimulation produces the same physiologic effect
Site, fiber type, and parameters matter.
Module 04 · Vagus Physiology: Afferents, Efferents, Reflexes
A
Lower-threshold A-fibers are recruited before C-fibers in electrical VNS
Standard electrophysiology.
Module 04 · Vagus Physiology: Afferents, Efferents, Reflexes
C
Selective fiber-type VNS is currently routine in clinical devices
Active research; not yet standard.
Module 04 · Vagus Physiology: Afferents, Efferents, Reflexes
A
The cholinergic anti-inflammatory pathway exists in animal models
Strong preclinical evidence.
Module 05 · Gut-Brain Axis & Neuroimmune Signaling
C
VNS broadly reduces inflammatory cytokines in humans across conditions
2024 meta-analysis: no consistent effect.
Module 05 · Gut-Brain Axis & Neuroimmune Signaling
B
VNS reduces RA disease activity in biologic-failure patients
RESET-RA pivotal trial supports SetPoint approval.
Module 05 · Gut-Brain Axis & Neuroimmune Signaling
B
Vagal afferents respond to gut nutrients and microbial metabolites
Supported in animal and some human work.
Module 05 · Gut-Brain Axis & Neuroimmune Signaling
E
Probiotic supplements 'tone the vagus'
Marketing language exceeds evidence.
Module 05 · Gut-Brain Axis & Neuroimmune Signaling
A
Left-sided VNS placement reduces cardiac risk vs right-sided
Standard surgical practice.
Module 06 · Implanted VNS: Device, Surgery, Programming, Safety
A
VNS can cause hoarseness and cough
Common, often dose-dependent, often improves with titration.
Module 06 · Implanted VNS: Device, Surgery, Programming, Safety
A
Implanted VNS systems have specific MRI conditions
Always check device labeling pre-imaging.
Module 06 · Implanted VNS: Device, Surgery, Programming, Safety
B
VNS worsens obstructive sleep apnea in some patients
Documented; screen patients with OSA history.
Module 06 · Implanted VNS: Device, Surgery, Programming, Safety
F
VNS provides immediate full effect at activation
Effect builds over months with titration.
Module 06 · Implanted VNS: Device, Surgery, Programming, Safety
F
VNS cures epilepsy in most patients
Adjunctive, not curative.
Module 07 · VNS for Epilepsy
A
VNS reduces seizure burden in a subset of drug-resistant patients
FDA-approved, AAN-supported.
Module 07 · VNS for Epilepsy
A
VNS effect builds over months to years
Time course well documented.
Module 07 · VNS for Epilepsy
B
Magnet activation can abort or attenuate some seizures
Patient-reported and observational support.
Module 07 · VNS for Epilepsy
C
Closed-loop cardiac-based seizure detection improves outcomes
Promising; trial evidence still maturing.
Module 07 · VNS for Epilepsy
A
VNS is FDA-approved for treatment-resistant depression
PMA approved.
Module 08 · VNS for Depression
F
VNS produces immediate antidepressant effect
Onset is delayed, often months.
Module 08 · VNS for Depression
B
Long-term observational data suggest sustained benefit in responders
Open-label extension data.
Module 08 · VNS for Depression
F
Sham-controlled depression VNS trials uniformly succeed
Mixed; sham design is challenging.
Module 08 · VNS for Depression
F
VNS is a first-line depression treatment
Strictly adjunctive after multiple failed trials.
Module 08 · VNS for Depression
A
Paired VNS improves UE motor outcomes vs sham + rehab in chronic ischemic stroke
FDA approved (Vivistim, P210007).
Module 09 · Paired VNS for Stroke Rehabilitation
F
Passive VNS during sleep produces motor recovery
Pairing with active rehab is essential.
Module 09 · Paired VNS for Stroke Rehabilitation
A
Benefit requires intensive paired-rehab sessions
Protocol-defined.
Module 09 · Paired VNS for Stroke Rehabilitation
C
Effect persists after device deactivation
Some retention reported; long-term data accumulating.
Module 09 · Paired VNS for Stroke Rehabilitation
D
Useful in acute stroke (<3 months)
Indication is for chronic stroke; acute use unproven.
Module 09 · Paired VNS for Stroke Rehabilitation
A
nVNS is FDA-cleared for acute episodic cluster headache
Established indication.
Module 10 · Non-Invasive Cervical VNS for Headache
F
nVNS is uniformly effective across all headache types
Evidence varies by indication; HTAs note mixed certainty.
Module 10 · Non-Invasive Cervical VNS for Headache
B
nVNS has a favorable safety profile vs many headache medications
Mostly mild local AEs.
Module 10 · Non-Invasive Cervical VNS for Headache
F
nVNS replaces triptans in acute migraine
Adjunctive or alternative; not equivalent.
Module 10 · Non-Invasive Cervical VNS for Headache
B
nVNS provides cluster prevention benefit as adjunct
Trial-supported in episodic cluster.
Module 10 · Non-Invasive Cervical VNS for Headache
A
SetPoint VNS is FDA-approved for RA after biologic failure
FDA PMA P240039 (2025).
Module 11 · VNS for Rheumatoid Arthritis & Inflammatory Disease
F
VNS replaces all DMARDs
Adjunctive/alternative for specific failure population.
Module 11 · VNS for Rheumatoid Arthritis & Inflammatory Disease
B
SetPoint produces ACR20/50 responses comparable to some biologic comparators
RESET-RA data; head-to-head vs biologics not yet definitive.
Module 11 · VNS for Rheumatoid Arthritis & Inflammatory Disease
F
VNS is FDA-approved for Crohn's disease
Investigational only as of 2025.
Module 11 · VNS for Rheumatoid Arthritis & Inflammatory Disease
C
SetPoint has favorable infection-risk profile vs biologics
Mechanistically plausible; long-term comparative data accumulating.
Module 11 · VNS for Rheumatoid Arthritis & Inflammatory Disease
B
taVNS is generally safe with mild, transient AEs in trials
Reporting quality varies (2022 meta).
Module 12 · Transcutaneous Auricular VNS & Emerging Stimulation
F
taVNS has standardized clinical dosing
No consensus on site/frequency/duration.
Module 12 · Transcutaneous Auricular VNS & Emerging Stimulation
C
Active taVNS improved chronic insomnia vs sham in a 2024 RCT
Single-center, replication needed.
Module 12 · Transcutaneous Auricular VNS & Emerging Stimulation
C
taVNS engages central vagal pathways measurable on fMRI
Some signal; replication and rigor heterogeneous.
Module 12 · Transcutaneous Auricular VNS & Emerging Stimulation
D
Earlobe placement is a physiologically inert sham
Increasingly questioned; may not be fully inert.
Module 12 · Transcutaneous Auricular VNS & Emerging Stimulation
F
Consumer ear-clip devices have FDA approval for stress relief
Most are wellness devices, not FDA-cleared for medical claims.
Module 12 · Transcutaneous Auricular VNS & Emerging Stimulation
B
Slow-paced breathing increases vagally mediated HRV
Supported.
Module 13 · Behavioral Autonomic Regulation
B
HRV biofeedback at resonance frequency reduces some anxiety symptoms
Multiple RCTs.
Module 13 · Behavioral Autonomic Regulation
E
Cold plunges 'reset the nervous system'
Marketing language exceeds evidence; risks exist.
Module 13 · Behavioral Autonomic Regulation
A
Aerobic fitness raises long-term HRV
Well-established.
Module 13 · Behavioral Autonomic Regulation
F
Humming or gargling 'tones the vagus' equivalently to a device
Not equivalent; modest autonomic effects only.
Module 13 · Behavioral Autonomic Regulation
F
Breath-hold protocols are universally safe
Risk in pregnancy, seizure disorder, cardiac disease.
Module 13 · Behavioral Autonomic Regulation
F
Polyvagal theory is settled neuroscience
Contested in primary literature.
Module 14 · Controversies, Myths & Polyvagal Theory
C
Polyvagal theory has clinical utility for some trauma-informed practitioners
Subjective utility ≠ mechanistic validation.
Module 14 · Controversies, Myths & Polyvagal Theory
E
All 'somatic' interventions are evidence-based
Mixed quality; some have good RCTs, many do not.
Module 14 · Controversies, Myths & Polyvagal Theory
F
Consumer ear-clip devices marketed for 'nervous system regulation' are FDA-cleared for those uses
Mostly wellness positioning, not medical clearance.
Module 14 · Controversies, Myths & Polyvagal Theory
B
Honest uncertainty improves patient trust
Communication research supports calibrated honesty.
Module 14 · Controversies, Myths & Polyvagal Theory