Electrical muscle stimulation is a conservative management tool for the treatment of pelvic floor dysfunctions (e.g., bladder and bowel incontinence, pelvic pain, dyspareunia, sexual dysfunction, and pelvic organ prolapse) that is supported by the 7th International Consultation on Incontinence from the International Continence Society and the International Consultation on Urological Diseases. The 2023 recommendations indicate that electrical stimulation can be considered for treatment to improve symptoms of Urge Urinary Incontinence, and that it can improve quality of life in females living with Stress Urinary Incontinence (grade of recommendations: B). Medical treatments (e.g., vaginal oestrogens) appear to be less effective than electrical muscle stimulation, or a combination of pelvic floor muscle training and electrical muscle stimulation for treatment of Stress Urinary Incontinence (grade of recommendation: B). Further, evidence suggests that magnetic electrical muscle stimulation, specifically, should be considered for improving symptoms in women living with Mixed and Stress Urinary Incontinence (grade of recommendation: B new) when compared to no active treatment. Despite the wide number of novel forms of emerging electrical muscle stimulation technologies, current research does not provide evidence about health outcomes based on the use of specific electrical muscle stimulation tools, procedures, and/or protocols. The objective of this scoping review was to: (1) summarize and critically evaluate available evidence about the outcome(s) of electrical muscle stimulation on pelvic floor dysfunction in adult women (as compared to alternative conservative care interventions); and (2) investigate the utility of intravaginal electrical muscle stimulation compared to extravaginal, high intensity treatment parameters compared to low intensity, and potential differences in treatment outcomes between electrical muscle stimulation modalities with, or without, a magnetic component.

A systematic scoping review methodology was used. Arksey and O’Malley’s framework was supplemented by the Joanna Briggs Institute methodology for scoping reviews. MEDLINE, EMBASE, and CINAHL databases were searched. Methodological quality of all included studies was scored independently by two raters. PRISMA’s extension for scoping reviews guideline was used. The inclusion criteria were: (1) studies that included participants who identified as adult females (i.e., ≥18 years of age); (2) participants that were diagnosed with any type of pelvic floor dysfunction (e.g., complaints of weakness, urinary or fecal incontinence, pelvic organ prolapse, and/or impaired sexual function); (3) study interventions involving any type of electrical muscle stimulation, including magnetic electrical muscle stimulation; (4) any treatments focused on the pelvic region and/or addressing a pelvic floor-related complaint, sign or symptom; (5) studies that included interventions using a conservative treatment in the comparison group; (6) studies that used self-report and/or objective assessment/outcome measures; and lastly, (7) studies published since 2017. All types of study designs were considered for inclusion. Published abstracts of studies meeting the above seven inclusion criteria were included. Articles not available in English or that were strictly theoretical, conceptual, or grey literature were excluded. Studies that used a form of electrical stimulation as an assessment tool or surgical intervention, that was not explicitly intended for treatment, were excluded.

A total of 40 articles published between 2017-2022 were included; 20 of which were randomized controlled trials. Most of the included studies were published in the United States, China, and Korea. A total of 15 of the studies used extravaginal stimulation and eleven used high frequency stimulation (≥ 50 Hz). Studies ranged from 1-hour in duration of electrical stimulation measuring immediate effects of stimulation on the pelvic floor musculature, while others took place over the course of 12-weeks with follow-up over 6-months. Low intensity treatments were found to require greater lengths of overall treatment time when compared to high intensity treatments, in addition, extra-vaginal and magnetic treatments were found to require less treatment time, thereby improving their clinical utility. However, it is not known if participants included in these studies saw significant improvements in outcomes because of the high intensity, extra-vaginal application, magnetic component, or a combination of these factors. Most studies included female participants living with Stress Urinary Incontinence. The number of participants in each study ranged from 15-720. Females living with pelvic organ prolapse, overactive bladder, fecal incontinence and sexual dysfunction were also included in the studies in this review.

Electrical muscle stimulation was found to improve symptoms on the outcome and assessment measures included in this review, and it facilitated improvement in symptoms for a variety of pelvic floor muscle dysfunctions, but notably, most participants included in this review were females living with Stress Urinary Incontinence. High intensity, extra-vaginal and magnetic modalities required less time to achieve significant therapeutic effects when compared to low or mixed intensity modalities and, therefore, may be more beneficial for use in clinical settings; however, all electrical muscle stimulation tools were found to provide significant improvements on outcome and assessment measures (e.g., the Pelvic Floor Disability Index, 3D transperineal U/S of pelvic floor integrity, Britsol’s Female Lower Urinary Tract Symptoms Questionnaire, the Pelvic Floor Impact Questionnaire – Short Form, the International Consultation on Incontinence Questionnaire Lower Urinary Tract Symptoms and the International Consultation on Incontinence Questionnaire – Urinary Incontinence).

Clinicians can use this information in conjunction with the 2023 recommendations from the International Consultation on Incontinence to provide appropriate and individualized care using high intensity, extra-vaginal and magnetic electrical muscle stimulation tools as time-effective adjunctive treatment tools for people living with pelvic floor dysfunctions. This may be particularly useful in women living with Stress Urinary Incontinence or who are unable to perform voluntary muscle contractions (i.e., some data suggests this is approximately 70% of women, see Subak et al., 2006 and Moen et al., 2009). This review fills a gap by identifying differences in outcomes between various electrical muscle stimulation tools, protocols and procedures that is necessary to inform clinicians on appropriate use of novel modalities in an individualistic manner.

Cardozo, L, Rovner, E, Wagg, A, Wein, A, Abrams, P. (Eds) Incontinence 7th Edition (2023). ICI-ICS. International Continence Society, Bristol UK, ISBN: 978-0-9569607-4-0.
Moen MD, Noone MB, Vassallo BJ, Elser DM, Urogynecology Network. Pelvic floor muscle function in women presenting with pelvic floor disorders. International Urogynecology Journal. 2009 Jul;20:843-6.
Subak, L.L., Brown, J.S., Kraus, S.R., Brubaker, L., Lin, F., Richter, H.E., Bradley, C.S., Grady, D. and Diagnostic Aspects of Incontinence Study (DAISy) Group, 2006. The “costs” of urinary incontinence for women. Obstetrics & Gynecology, 107(4), pp.908-916.