Vagus stimulation devices on the market

• ›Drug-resistant focal epilepsy (≥4 yrs, adjunctive) — approved 1997
• ›Treatment-resistant depression (adjunctive) — approved 2005
• ›AspireSR/SenTiva: closed-loop ictal-tachycardia detection (AutoStim)

Helical platinum-iridium electrodes around left cervical vagus, IPG implanted infraclavicularly. Delivers chronic intermittent stimulation; some models trigger extra bursts on heart-rate rise (seizure proxy).

Typical: 0.25–2.0 mA, 20–30 Hz, 250–500 µs, 30 s ON / 5 min OFF. Titrated over weeks.

Epilepsy: ~50% of patients achieve ≥50% seizure reduction at 2 yrs (open-label cohorts). TRD: RECOVER trial (2024) showed modest but durable response/remission gains over sham at 12 months in adjunctive use.

Surgical risks (vocal-cord paresis, infection). Voice alteration, cough, dyspnea during ON-cycle very common. Not curative. MRI compatibility model-dependent.

• ›Moderate-to-severe rheumatoid arthritis (RESET-RA pivotal trial)
• ›Multiple sclerosis (exploratory)

Miniaturized leadless cervical VNS implant; brief once-daily stimulation aimed at engaging the cholinergic anti-inflammatory pathway (α7-nAChR on splenic macrophages).

Typically 1 minute/day, low charge per day vs epilepsy devices.

Pilot RA studies (Koopman 2016, Genovese 2020) showed ACR20 responses; RESET-RA pivotal results pending FDA review (2024–2025).

Not yet FDA-approved as of 2025. Still surgical. Long-term immune effects under study.

• ›Acute treatment of episodic cluster headache (adults)
• ›Prevention of cluster headache
• ›Acute and preventive treatment of migraine (adults & adolescents 12+)
• ›Adjunctive use in hemicrania continua and paroxysmal hemicrania (off-label/CE)

Handheld device delivers proprietary 5 kHz sinusoidal burst (~24 V) over the cervical vagus through the skin for 2-min doses. Engages cervical vagal afferents; CNS effects on trigeminocervical complex proposed.

120 s stimulations, typically 2–3 doses per attack; up to 24 doses/day for prevention.

ACT1/ACT2 cluster trials and PRESTO/PREMIUM migraine trials show modest but real benefit vs sham. Insurance coverage is patchy.

Skin tingling, neck discomfort. Avoid over carotid bifurcation, bypassed cardiac conduction, metallic implants in neck. Battery cards limit doses.

• ›Drug-resistant epilepsy (CE)
• ›Depression (CE, EU)
• ›Used widely in research for HRV, inflammation, cognition studies

Ear electrode targeting the auricular branch of the vagus nerve (cymba conchae). Delivers biphasic pulses; stimulation perceived as gentle tingling.

25 Hz, 250 µs, 0.1–10 mA titrated to comfort; typical research dosing 30–60 min/day.

Mixed: small/medium RCTs show effects on HRV, mood, and pain; large pivotal trials still lacking. CADET-RA (2025) and migraine pilots ongoing.

CE ≠ FDA. Not approved for medical use in the US. Effect sizes in research are small and heterogeneous.

• ›Marketed in EU/UK for HRV, stress, sleep, long-COVID symptoms (registered medical device)
• ›Investigational in long-COVID, POTS, AFib trials

Tragus-clip taVNS, biphasic square pulse; mobile-app-controlled.

Default 200 µs, 30 Hz, ramped intensity; sessions ~30–60 min daily.

Several small academic trials (HRV, POTS, AF burden). Long-COVID and AFib RCTs underway. Independent replication still limited.

Marketed direct-to-consumer with strong wellness framing; consumer claims can outpace evidence.

• ›General wellness, HRV, stress; clinic-based protocols

Bilateral auricular taVNS with Bluetooth biofeedback (HRV).

Adjustable frequency 1–100 Hz, 100–500 µs, intensity titrated.

Mostly company-sponsored or small academic studies; growing clinic adoption in EU.

Not FDA-cleared. Evidence base thinner than NEMOS / Parasym.

• ›General wellness: stress, sleep, focus (no medical indications)

Same hardware family as gammaCore but marketed as a general-wellness device — direct-to-consumer, no prescription, no specific medical claim.

2-min cervical sessions, 1–4×/day.

Borrows mechanistic plausibility from gammaCore; no condition-specific RCT supports the consumer wellness positioning.

Wellness label intentionally avoids FDA medical-device review for new claims. Don't infer migraine/cluster benefit from gammaCore data.

• ›Marketed for stress, anxiety, sleep, burnout, pain, focus

Neck-worn device delivering low-intensity electrical pulses claimed to stimulate the cervical vagus.

App-selectable 'modes' (sleep, calm, etc.); 4-min sessions.

No peer-reviewed RCTs as of 2025. Marketing claims rely on general taVNS/cVNS literature, not device-specific trials.

Aggressive direct-to-consumer marketing. Not a medical device. Treat as wellness, not therapy.

• ›Relaxation, stress, sleep — general wellness

Earbuds deliver micro-current synchronized with music, claimed to stimulate auricular vagal branch.

Adjustable intensity; sessions of variable length.

No published RCTs. Mechanism plausibility relies on auricular VNS research with different hardware/parameters.

Wellness device; do not substitute for medical taVNS protocols.

• ›Stress, sleep, focus, HRV

Wrist/ankle vibrotactile patterns — NOT electrical VNS. Often grouped with vagal tools, but it stimulates mechanoreceptors, not the vagus directly.

Small studies showing HRV shifts; mechanism is sensory/parasympathetic entrainment, not vagal-nerve stimulation per se.

• ›Stress reduction, sleep, HRV

Chest-placed device delivers low-frequency infrasonic resonance + paired audio. Claimed to engage vagal tone via thoracic resonance.

One company-funded RCT (2022) and several small studies; replication limited.

• ›Academic taVNS / cVNS research only

Constant-current isolated pulse generators allowing precise parameter control for trials.

Fully configurable — used to define dosing windows that consumer devices later approximate.

Underpins most published mechanistic taVNS data (HRV, P300, inflammatory markers).

Not for clinical or home use. Mentioned so learners can interpret the literature.