Table 1.

Characteristics of included studies.

Study (year)	Design	Duration (year)	Group	N (women/men)	Age (years)	Treatment protocol	Stimulation parameters	Follow-up
Ramírez-García (2019)	RCT	2015–2016	TTNS	21/13	62.4 ± 16	30 min/wk	20 Hz and 200 cycles	12 wk
			PTNS	25/9	56.8 ± 16	30 min/wk	20 Hz and 200 cycles	12 wk
Martin-Garcia (2019)	RCT	2015–2016	TTNS	12/0	54 ± 12	≥30 min × 3/wk	20 Hz and 200 cycles	6 mo
			PTNS	12/0	58 ± 10	30 min/4 wk	20 Hz and 200 cycles	6 mo
Alfonso Barrera (2013)	R	2011–2012	TTNS	21/0	–	30 min/wk	20 Hz and 200 cycles	12 wk
			PTNS	13/0	–	30 min/wk	20 Hz and 200 cycles	12 wk
Maurelli (2012)	Before and after	–	TTNS	13/3	–	30 min/wk	20 Hz and 200 cycles	19.7 mo
			PTNS	13/3	–	30 min/wk	20 Hz and 200 cycles	–