Table 1.

Summary of invasive vagus nerve stimulation (iVNS) studies.

Author	Sample	Parameters	Main Outcomes
			Pain	Affect
Borckardt et al., 2005	Depression n = 8	Combination of: 20 Hz/30 Hz; 130μs/250μs/500μs pw at 0%, 50%, 100% of basline intensity (0–2.75 mA)	↓ heat tolerance	Not reported
Borckardt et al., 2006	Depression/low back pain n =1	10 Hz or 20 Hz, 250μs s or 500μs s pw 0–0.75 mA 30s on, 3–20 min off	↓ low back pain ↑ experimental pain ratings ns pain thresholds	↓ depression
Cecchini et al., 2009	Migraine n = 4	30 Hz, 500ms pw 1–2.25 mA 30s on, 5min off	↓ migraine	↓ depression
Hord et al., 2003	Migraine n = 4	30 Hz, 500ms pw ~1.0 mA 30s on, 5min off	↓ migraine frequency/intensity	Not reported
Kirchner et al., 2000	Epilepsy n = 10 Healthy n = 12	30 Hz, 500μs s pw initial: 0.7 ± 0.2 mA final: 1.4 ± 0.3 mA	↓ wind-up, pressure pain in patients, comorbid migraine ns thermal, mechanical pain	Not reported
Kirchner et al., 2006	Epilepsy n = 9 Healthy n = 9	for majority: 20 Hz, 500μs s pw 30s on, 30s off	↓ tonic pressure pain in patients ↓ axon reflex flux	Not reported
Lange et al., 2011	Fibromyalgia n = 14	20 Hz, 250μs s pw, 1–2 mA 30s on, 5 min off	↓ fibromyalgia symptoms ↓ heat pain sensitivity ↓ pain intensity	Not reported
Lenaerts et al., 2008	Migraine n = 10	Not reported	↓ migraine frequency	↓ (ns) mood/anxiety
Mauskop 2005	Migraine n = 6	250ms pw, 1.25–2.75mA 7–60s on, 0.2–5 min off,	↓ migraine/frequency	↓ prodromal depression
Ness et al., 2000	Epilepsy n = 8	30 Hz, 0.5ms pw 1.0–2.75 mA 30s on, 3–5min off	↓ heat pain thresholds	Not reported
Sadler et al., 2002	Epilepsy/Migraine n = 1	final: 20 Hz, 250μs s pw 0.25 mA 7s on, 12s off	↓ migraine frequency	Not reported

↓, decrease

↑, increase

ns, non-significant

pw, pulse width