Effect of theta-transcranial alternating current stimulation on working memory performance among healthy adults: A systematic review and meta-analysis

Table 3 Delayed match-to-sample task subgroup analyses

Covariables	Subgroups	Number of effect sizes	Hedges’ g	95%CI	I² (%)	τ²	P value
Study design							0.564
	Within-subject	15	0.092	-0.197 to 0.380	76.00	0.255
	Between-subject	2	-0.090	-0.636 to 0.456	0.00	0
Target region							0.012
	Frontoparietal	10	-0.082	-0.490 to 0.326	78.10	0.346
	Parietal	3	0.574	0.277-0.871	0.00	0
	Frontal	4	0.077	-0.173 to 0.328	0.00	0
Concurrent task							0.295
	Online	15	0.105	-0.185 to 0.395	75.40	0.252
	Offline	2	-0.168	-0.588 to 0.253	0.00	0
Task modality							0.433
	Spatial	7	0.005	-0.642 to 0.652	87.60	0.680
	Verbal	4	0.020	-0.241 to 0.280	0.00	0
	Objective	6	0.226	0.022-0.430	0.00	0

CI: Confidence interval.