Table 1. Summary of studies using tES assumed to target PAC for the investigation of speech and non-speech auditory perception (non-speech studies are marked with an asterisk).

Study	population	N	Method	“Active” electrode	“Reference” electrode	Protocol	Timing	Outcome	Control
Marques et al. (2014)	Healthy	24	tDCS	T3/T4 (corr. to T7/T8)	Right deltoid muscle	20 min. of 2 mA	Online	Bilateral cathodal (but not anodal) tDCS decreases McGurk effect	Sham (same subjects)
Heimrath, Fischer, et al. 2016	Healthy	13	tDCS	T7/T8	Cz	22 min. of 1.5 mA	Online	Bilateral cathodal (but not anodal) tDCS improves phonetic categorisation	Sham (same subjects)
Neuling, Rach, Wagner, Wolters, and Herrmann (2012)*	Healthy	16	otDCS	T7/T8	n/a	DC of 1 mA + 10 Hz AC of 0.425 mA (mean), 2 × 21 min.	Online	Detection of non-speech target tones embedded in noise depends on phase of the imposed current	No control
Riecke, Formisano, et al. (2015)*	Healthy	14	tACS	T7/T8	Cz	4 Hz, 0.8 mA (mean), 39.6 min.	Online	Detection of click trains depends on phase of the imposed current	Sham (same subjects)
Riecke, Sack, et al. (2015)*	Healthy	20	tACS	T7/T8	Cz	4 Hz, 0.8 mA (mean), 40 min.	Online	Time required to segregate non-speech target sounds from background sounds depends on tACS phase	Sham (same subjects)
Rufener, Zaehle, et al. (2016)	Healthy	21 (+17 for no stim.)	tACS	T7/T8	n/a	40 Hz, 1.1 mA (mean), 18 min.	Offline	40-Hz (but not 6-Hz) tACS impairs learning performance in phonetic categorisation task	No stimulation, control frequency
Rufener, Oechslin, et al. (2016)	Healthy	25	tACS	T7/T8	n/a	40 Hz, 1.38 mA (mean), 8 min.	Online	Replicate previous study and show that results are reversed for older listeners	Control frequency

Note: Stimulation methods (tDCS/tACS/otDCS and electrode locations) are illustrated in Figure 1.