Table 4.

Non-invasive neuromodulation clinical trials in acute and preventive cluster headache treatments

Device type*	Studies (n)	Enrolled population (total n)	Blinded studies (n)†	Sham-controlled studies (n)	Percentage of studies evaluating IHS- recommended endpoints
					Primary endpoint (%)‡	Secondary endpoint (%)‡
Acute cluster headache treatments
Non-invasive vagus nerve stimulation (nVNS)	2	253	2	2	100	100
Preventive cluster headache treatments
Non-invasive vagus nerve stimulation (nVNS)	1§	97	0	0	100	100
Transcranial direct current stimulation (tDCS)	1	32	0	0	0	100

*All references for studies in this table are listed in the online supplementary references.

†Double-blind or better.

‡Percentage of efficacy studies in which either a primary or a secondary endpoint recommended by the International Headache Society was used. Safety studies were excluded from this calculation.

§Marin et al’s study (used for recent Food and Drug Administration clearance) not included here as it was published outside of predefined date range.

IHS, International Headache Society.