Table 1.

The details of individual study

Study	Country	Study design	Treatment		Sample size (boys/girls)		Mean age (yr) ± SD		Intervention period	Nerve stimulation scheme	Main inclusion criteria
			Experimental	Control	Experimental	Control	Experimental	Control
Hagstroem et al. (2009) [21]	Denmark	RCT	TENS	Sham	13 (7/6)	12 (3/9)	8.7 ± 2.0	8.5 ± 1.2	4 Weeks	10-Hz frequency with a 200-μsec pulse duration and biphasic waveform; 2 hours daily.	Age 5 to 14 years, daytime urinary incontinence at least 2 days per week, urgency, normal urinalysis, unremarkable urinary tract ultrasound and normal physical examination. Incontinence had to be refractory to a minimum of 12 months of urotherapy.
Lordêlo et al. (2010) [20]	Brazil	Single-blind, prospective RCT	TENS	Sham	21 (8/13)	16 (4/12)	7.5 ± 3.0	7.4 ± 2.8	20 Sessions, 3 times weekly	20 Sessions of TENS, 10-Hz frequency with a generated pulse of 700 μsec; 3 times weekly, with sessions of 20 minutes.	Children older than 4 years with OAB.
Sillén et al. (2014) [19]	Sweden	RCT	TENS+Standard urotherapy	Standard urotherapy	30 (19/11)	32 (16/16)	8 ± 1.5	8 ± 1.9	12 Weeks	Twice a day for 20 minutes each time; 10-Hz frequency; maximal level tolerated by the child and reached a maximum of 40 mA.	Children 5–12 years; Micturition frequency≥7; Incontinence episodes ≥ 1 within 7 days; Urgency.
Patidar et al. (2015) [18]	India	Single-blind, prospective RCT	PTNS	Sham	21 (N/A)	16 (N/A)	7.71 ± 2.22	8.38 ± 2.27	12 Weeks	Adjustable voltage pulse intensity of 0–10 mA, a fixed pulse width of 200 μsec, and a frequency of 20 Hz; A weekly session of 30 minutes.	Non-neurogenic OAB unresponsive to behavioral therapy and at least 6 months of anticholinergic medication.
Boudaoud et al. (2015) [17]	France	Doubleblind RCT	PTNS	Sham	11 (5/6)	9 (5/4)	11 ± N/A	10 ± N/A 12	Weeks	Below the pain threshold at 10 mA, frequency at 10 Hz, and continuous stimulation of 200 msec during 30 minutes; Two sessions per week.	Children over the age of 6 with primary or secondary nonneurogenic OAB; Absence of anatomical abnormality in the lower urinary tract; Partial response or non-response to anticholinergics after a wellconducted treatment of at least 6 consecutive months.
De Paula et al. (2017) [16]	Brazil	Doubleblind prospective RCT	PTENS+Urotherapy guidelines	Urotherapy guidelines	8 (3/5)	8 (3/5)	6.5 (6.0–7.7)	8.5 (5.5–10)	60 Days	Once a week, lasting for 20 minutes, at a frequency of 10 Hz, pulse width of 700 msec, and variable intensity determined by the tolerance threshold of the child.	Aged 3–18 years of age with a clinical diagnosis of OAB not previously treated for this disease or having gone at least 6 months without any treatment.
Borch et al. (2017) [15]	Denmark	Doubleblind RCT	TENS	Placebo	12 (7/5)	12 (9/3)	8.8 ± 2.1	8.5 ± 1.2	48 Hours	A 10-Hz frequency with a 200-sec pulse duration and biphasic waveform; The children were instructed to use the highest tolerable intensity with a maximum of 40 mA.	Age 5–14 years, overactive bladder, daytime urinary incontinence at least 2 days/week and a minimum of 5 micturitions/day. Refractory to a minimum of 12 months of standard urotherapy and 3 months of pharmacotherapy.
Borch et al. (2017) [14]	Denmark	Doubleblind RCT	TENS+oxybutynin	Oxybutynin	22 (11/7)	23 (10/4)	7.65 ± 1.77	7.48 ± 1.57 10	Weeks	A 10-Hz frequency with a 200-sec pulse duration and biphasic waveform; Children were instructed to use the highest tolerable intensity up to a maximum of 40 mA.	Age 5–14 years; Urge incontinence >2 x/wk; >4 micturitions/day; Ongoing symptoms of OAB; Refractory to >2 months of standard urotherapy; A normal physical examination.

SD, standard deviation; RCT, randomized controlled trial; TENS, transcutaneous electrical nerve stimulation; PTNS, transcutaneous posterior tibial nerve stimulation; PTENS, parasacral transcutaneous electrical neural stimulation; N/A, not available; OAB, overactive bladder.