Pulsetto and Vagus Nerve Stimulation: Clinical Guidelines
Critical Distinction: Pulsetto is NOT FDA-Approved for Medical Use
Pulsetto is a consumer wellness device for transcutaneous vagus nerve stimulation (tVNS) and is NOT FDA-approved for treating any medical condition, including epilepsy or depression. 1, 2
FDA-Approved VNS Indications
The FDA has approved implantable vagus nerve stimulation (iVNS) for only three specific medical conditions:
- Refractory epilepsy (approved 1997) - as adjunctive therapy after failure of ≥2 anti-epileptic drugs 3, 1, 2
- Treatment-resistant depression (approved 2005) 3, 4
- Obesity (approved 2015) 3
Key Point on Device Type
FDA approval applies exclusively to surgically implanted VNS systems (such as LivaNova VNS device) that place helical cuff electrodes on the left cervical vagal trunk connected to an implanted pulse generator in the chest. 1 Consumer transcutaneous devices like Pulsetto do not have this approval and should not be used for medical treatment.
Evidence-Based Parameters for FDA-Approved Implantable VNS
For Refractory Epilepsy
Standard therapeutic parameters established through pivotal E03 and E05 trials: 3, 2
- Output current: 0.25-3.5 mA (gradually titrated to maximum tolerable level, typically 1.0-1.5 mA) 4
- Frequency: 30 Hz 3
- Pulse width: 500-750 µsec 3
- Duty cycle: 30 seconds ON + 5 minutes OFF 3
Expected outcomes: Approximately 51% of patients achieve ≥50% reduction in seizure frequency 3, 5, 2
Optimization Strategy for Non-Responders
For patients not responding to initial settings, increase duty cycle by reducing OFF time from 5 minutes to ≤1.1 minutes, which improved responder rates from 19% to 35% (p = 0.046). 3, 5, 2
For Treatment-Resistant Depression
Typical parameters differ slightly: 4
- Frequency: 20 Hz (versus 30 Hz for epilepsy) 4
- Pulse width: 250 or 500 µsec 4
- Other parameters: Similar to epilepsy settings 4
Mechanism and Fiber Activation
Therapeutic effects are mediated by large-diameter myelinated A-fibers, not C-fibers as previously hypothesized. 3 Clinical stimulation intensity remains subthreshold for B-fibers (no bradycardia observed) and far below C-fiber activation thresholds (46-fold higher than A-fiber thresholds). 3
Common Side Effects and Management
Stimulation-related side effects (all related to A-fiber activation during ON phase): 3, 6, 7
- Voice alteration/hoarseness
- Cough
- Throat tightening sensation
- Dyspnea
- Paresthesias
Management approach: These side effects typically diminish with time and can be controlled by adjusting stimulation parameters (primarily reducing output current). 6, 8 Unlike antiepileptic drugs, VNS does not cause cognitive side effects. 6, 8
Surgical complications occur in ~3% of patients (primarily infections treatable with oral antibiotics). 6
Critical Safety Considerations
- Sleep apnea: iVNS may worsen existing sleep apnea syndrome, requiring nighttime therapy interruption through day-night programming or magnet use. 8
- SUDEP risk: Newer closed-loop systems with cardiac-based seizure detection may reduce risk of sudden unexpected death in epilepsy patients. 8
Transcutaneous VNS (tVNS) Evidence Gap
Non-invasive transcutaneous devices are less effective than implantable systems for both epilepsy and depression, with insufficient high-quality evidence supporting their use. 8 These devices require active patient application (not continuously active like implanted systems), creating adherence concerns. 8
Clinical Decision Algorithm
- Confirm FDA-approved indication: Patient must have refractory epilepsy (failed ≥2 AEDs) or treatment-resistant depression 1, 5, 2
- Exclude non-approved indications: Stroke rehabilitation, post-stroke hemiparesis, and other conditions remain experimental with insufficient evidence 1
- Use only FDA-approved implantable devices: Consumer transcutaneous devices like Pulsetto lack approval for medical treatment 1, 8
- Implement evidence-based parameters: Start with standard settings and systematically adjust based on response 3, 4