Table 2.

Reported effects of transdermal vagal stimulation on autonomic cardiovascular parameters, inflammation, and symptoms in humans.

Author	Sample	Site & parameters	Main outcomes
Author	Sample	Site & parameters	HR	Vagal indices	LF/HF	BP	MSNA	Infl	Symp
Aranow et al. (2021)	SLE N= 18	Left concha/posterior ear 30 Hz, 300 µs pw. max tolerated	•	•	•	•	•	=	↓
Paleczny et al. (2021)	Healthy controls N= 12	25 Hz, 1000 µs/phase, 30 µs interphase interval. 10 µA, 80% pain threshold	↓	=	=	=	•	•	•
Drewes et al. (2021)	Rheumatoid arthritis N = 36	Cervical vagus nerve 1 ms, 5 sine waves, 200us; 1burst/40 ms, 25 Hz, 60 mA, 24 V	•	↓	•	•	•	↓	↓
Gauthey et al. (2020)	Healthy males N = 23	Right cymba 5–20 Hz, 200 µs pw, sensory perception Right Lobe (sham): 5 Hz, 200 µs pw, sensory perception	↓	=	↑	=	↓	•	•
Borges et al. (2019)	Healthy controls N = 61	Left cymba conchae 25 Hz, 200–300 µs, 0.1–1.0 mA, on-off 30s cycle, different intensities	•	↑	•	•	•	•	•
Tobaklini et al. (2019)	Healthy controls N = 13	Left cymba conchae 25 Hz, 200 µs pw, 1–6 mA	↓	=	=	=	•	•	•
Badran et al. (2018)	Healthy controls N= 15	Left tragus 1/10/25 Hz; 100/200/500 µs; 60s; 200% pain threshold	↓	•	•	•	•	•	•
Colzato et al. (2018)	Healthy males N = 32	Left cymba conchae 0.5 mA 200–300 µs at 25 Hz, 30 min	↓	•	•	•	•	•	•
Antonino et al. (2017)	Healthy males N = 13	Left tragus 30 Hz, 200 µs pw 10–50 mA	↓	=	↓	=	•	•	•
De Couck et al. (2017)	Healthy controls N = 30	Left cymba conchae vs right cymba conchae 25 Hz, 250 µs pw, ±1 mA 30s; 50% pain threshold	•	↑	↑	•	•	•	•
Wang et al. (2015)	Myocardial Infarction N = 42	Left tragus vs right tragus 30 Hz, 200 µs pw, 10–50 mA	•	•	↓	•	•	•	•
Stavrakis et al. (2015)	Atrial Fibrillation N = 42	Right tragus 20 Hz; 250–200 ms/cyde	↓	•	•	•	•	↓	•
Clancy et al. (2014)	Healthy controls N = 4S	Tragus 30 Hz, 200 µs pw, 10–50 mA	↓	=	↓	•	↓	•	•
Popov et al. (2013)	Coronary artery disease N = 43	Bilateral cymba concha 3 Hz, 0.2– 1.5 mA, 1.5 ms,	↓	•	•	•	•	•	↓
Rong et al. (2012)	Depression N= 49	Cymba concha 20 Hz, 1 mA	•	•	↓	•	•	•	•
Zamotrinsky et al. (2001)	Preoperative coronary artery disease N = 38	Bilateral cymba concha 0.2–1.5 mA, 1.5 ms, 3 Hz	↓	•	•	↓	•	•	↓
Zamotrinsky et al. (2001)	Preoperative coronary artery disease N = 20	Bilateral cymba concha 0.2–1.5 mA, 1.5 ms, 3 Hz	•	•	•	•	•	•	↓

HR, heart rate; LF/HF, ratio between the low and high frequency components of heart rate variability; BP, blood pressure; MSNA, muscle sympathetic nerve activity; lnflam, inflammation; Symp, symptoms; pw, pulse width; ↑ increased; — unchanged; ↓ decrease.