Overactive bladder (OAB) is a highly prevalent condition and negatively impacts a woman's quality of life and activities of daily living. Behavioral therapy and low-frequency electrical stimulation are currently proven therapeutic alternatives for symptoms of urinary urgency, with few side effects and low cost [1]. On the other hand, medium frequency current, such as AUSSIE, is not commonly used for the treatment of OAB. Thus, this original study aims to compare the effectiveness of transcutaneous parasacral electrical stimulation with transcutaneous tibial electrical stimulation in the treatment of female OAB and to evaluate the non-inferiority of AUSSIE current in relation to TENS and the home protocol in the treatment of OAB.

This is a randomized clinical trial, in which women aged between 18 and 65 years with urinary symptoms of OAB were included. Participants with OAB due to neurological impairment, lower urinary tract infection, sensory deficit in the sacral or tibial region, chronic renal failure, implantable cardioverter defibrillator and pregnant women were excluded.After signing the free and informed consent, the participants were instructed to fill in the voiding diary (VD) for 3 days and answered sociodemographic information and anamnesis. The following week, after delivery of the VD, they answered the International Consultation on Incontinence Questionnaire Overactive Bladder (ICIQ-OAB) and the post-mictional residue (PMR) was evaluated by ultrasound.

Randomization was performed into four groups:
	• EETPA-TENS: ambulatory parasacral transcutaneous electrical stimulation with low frequency;
	• EETPA-AUSSIE: ambulatory parasacral transcutaneous electrical stimulation with medium frequency;
	• EETTA-AUSSIE: ambulatory transcutaneous tibial electrical stimulation with medium frequency; 
	• EETPD-TENS: home transcutaneous parasacral electrical stimulation with low frequency.

The treatment for the groups (EETPA) using TENS and AUSSIE consisted of 30 sessions performed three times a week with intensity according to the participant's tolerance, at the sensitive threshold, without muscle contraction, with the positioning of the self-adhesive electrodes either in the parasacral or in the region of the tibial nerve, according to the group. In the TENS current protocol, the Neurodyn Portable TENS device (IBRAMED, Amparo, São Paulo, Brazil) was used, the wave frequency used was 10 Hz, the pulse width of 500 µs and for 20 minutes. In the AUSSIE current protocol, the device Neurodyn 10 Channels (IBRAMED, Amparo, São Paulo, Brazil) was used, the frequency was 4 KHz, pulse width of 4 ms, burst frequency of 100 Hz, in continuous mode and for 30 minutes. For the EETPD-TENS group, 70 sessions were performed daily, guided and monitored weekly by a trained researcher, with the same protocol as for the EETPA-TENS group. 

To assess the clinical response, the Visual Analog Scale (VAS) and the Likert Scale (very dissatisfied, dissatisfied, unchanged, satisfied, very satisfied) were applied, as well as the ICIQ-OAB and the PMR.

The paired t test was used to compare intragroup numerical variables, and the chi-square test was used to compare categorical variables between groups. The significance level adopted was 5%.

Forty-four women were evaluated for eligibility. There was a loss of 12 volunteers due to withdrawal. After starting the treatment intervention, 2 volunteers were excluded and 7 volunteers dropped out of the study. For this sample, we completed a total of 23 participants randomized into 4 groups: EETPA-TENS (7), EETTA–Aussie (5), EETPA–Aussie (4) and EETPD–TENS (7). The sociodemographic and clinical characteristics of the patients were homogeneous. The mean age ranged from 47.3 ± 13.5 to 55.7 ±7.3, with the majority presenting urinary loss due to urgency, constipation, similar degree of muscle strength (median varying between 2 and 3) and the majority being in menopause (Table 1).

It was possible to identify a statistically significant reduction in the ICIQ-OAB score in the EETTA-Aussie group; a clinically significant reduction in the EETPA-Aussie and EETPA-TENS groups and no change in the EETPD-TENS group. In relation to the PMR, there was a change in all groups when comparing the USG before and after treatment, but without statistical difference. In the VD analysis, it was possible to notice a reduction in the frequency of urination (except in the EETPD-TENS) and an increase in the bladder capacity of the patients, but without statistical significance (Table 2). Regarding the improvement of urinary symptoms measured by the VAS modified for urinary infection, in the intragroup analysis, it was possible to identify an improvement in all groups, and, in the intergroup analysis, no treatment was superior to the other. In assessing the degree of satisfaction, no difference was identified between treatments (p=0.279), with most patients being satisfied or very satisfied with the outcome of the treatment (Table 2). Furthermore, there were no adverse events reported in either group.

When observing the preliminary results, there are no data that support that there is a superior therapy to the others. It is possible to observe that the perception of improvement and satisfaction with the treatments performed is statistically superior to the quantitative findings represented in the study by the ICIQ-OAB, the VD and the USG. In a descriptive analysis, the EETPD-TENS group presented the quantitative evaluations with less modification (maximum bladder capacity and VAS) or no modification (ICIQ-OAB, voiding frequency). This may have happened because the patients had a greater volume of PMR than the patients in the other groups. They obtained an average reduction of 20ml in the PMR, but the PMR still remained above 30ml.

Although electrostimulation is recommended by the guidelines, there is still no consensus regarding the best type of therapeutic current and parameters for the treatment of female OAB. Similar studies have already been carried out, demonstrating that both forms of transcutaneous electrical stimulation seem to be effective and safe in the home treatment of women with OAB. [2] A study, in an elderly population, showed that there is no significant difference between the groups, both proposed treatments are effective in improving OAB in elderly women. [3]

It should be noted that the slight improvement found in some data deserves further investigation, since this finding may have been both by chance and also the result of a tendency for patients to respond better to this treatment mechanism. In addition to the considerations made, it should be noted that the low sample size is defined as the main limitation, plus the lack of follow-up after the end of the sessions.

The dropout and abandonment rate was very high and the main reason given by the patients was the difficulty of going to the service three times a week, either because of not having the time available, or because they did not have the money to pay for transportation. In this sense, home electrical stimulation could overcome these difficulties.

The research shows that, based on the patients' perception of improvement, there is no place or therapeutic current superior to the other and that all of them seem to bring a satisfactory therapeutic effect in the context of OAB in women. The sample size is still very small, requiring the continuation of the clinical trial, for more assertive conclusions.

Abrams P, Andersson K, Birder L, et al. 4th international consultation recommendations of the International Scientific Committee: the major evaluation and treatment of urinary incontinence, pelvic organ prolapse and faecal incontinence. Neurourol Urodyn. 2010;29:213–240.
Mallmann S, Ramos JGL, Paiva LL. Comparação da eletroestimulação transcutânea parassacral com a eletroestimulação transcutânea de nervo tibial posterior em mulheres com síndrome da bexiga hiperativa: um ensaio clínico randomizado. Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil, 2018.
Jácomo RH, de Souza JB, Alves AT. Estudo comparativo entre e eletroestimulação transcutânea do nervo tibial posterior e a transcutânea parassacral no tratamento da síndrome da bexiga hiperativa em mulheres idosas. Universidade de Brasília, Brasília, Brazil, 2019

Continence 7S1 (2023) 100745
DOI: 10.1016/j.cont.2023.100745