Electrical stimulation of the dorsal genital nerve (DGN) has shown promising results in experimental settings in the treatment of overactive bladder (OAB) syndrome. UCon neurostimulator is a novel portable device designed to provide electrical stimulation of the DGN at clitoris or penis in a home setting. This study aimed to test UCon neurostimulation in women (w) and men (m) diagnosed with idiopathic OAB syndrome. We hypothesized that stimulation of DGN would be safe without serious adverse events, reduce urinary frequency, number of urgency urinary incontinence (UUI) episodes, and improve quality of life (QoL).

The study was a prospective, multicenter, feasibility study. Inclusion criteria were 18 years or older with OAB syndrome. Exclusion criteria were treatment with onabotulinumtoxinA within three months or treatment with antimuscarinics or beta-3 agonists within two weeks.  At baseline, participants completed a seven-day bladder diary documenting UUI episodes, urinary frequency, and fluid intake. DGN stimulation protocol included a four-week stimulation, either as time-limited stimulation (30 minutes daily) or on-demand stimulation during urgency episodes based on participant preference and expected effect by the physician from the medical history. Presented results are based on raw data analysis, including bladder diaries and International Consultation on Incontinence Questionnaire Overactive Bladder (ICIQ-OAB) questionnaires.

We enrolled 39 participants with a dropout/withdrawal of 10 participants. One participant was included in the on-demand stimulation group and, after a washout period, in the time-limited stimulation group. Overall median age at inclusion was 60 (Q1-Q3: 51.8-69) years. No serious device adverse events were reported during the trial period.
In the time-limited stimulation group (18 participants, w: 11, m: 7), median number of voids per day was significantly reduced from 11.3 (Q1-Q3: 9-13.2) to 9.1 (Q1-Q3: 7.8-11.2, p=0.002). In the subgroup with UUI episodes at baseline (n=14), median number of UUI episodes per seven days by the fourth stimulation week decreased significantly from 11.5 (Q1-Q3: 1-14) to 1.5 (Q1-Q3: 0-5, p=0.001). Among these, 11 out of 14 (78.6%) participants had a 50% reduction in UUI episodes, and 7 out 14 (50%) became continent by the fourth week of stimulation. Median ICIQ-OAB total bother score after intervention decreased significantly from 29.5 (Q1-Q3: 26.2-34.5) to 25 (Q1-Q3:17.5-28.8, p=0.002). 

In the on-demand stimulation group (11 participants, w:9, m:2), a significant median change in voids per day from 12.4 (9.2-13.2) to 11 (8.9-12, p=0.014) was observed. In the subgroup with UUI episodes at baseline (n=10), UUI episodes per seven days decreased insignificantly from 22 (Q1-Q3: 16.8-25) to 11.5 (Q1-Q3: 4.3-19.8, p=0.155). Of these, 7 out of 10 (70%) participants had a 50% reduction in UUI episodes, one became continent, and two experienced more UUI episodes by the fourth week of stimulation. No significant improvement of median ICIQ-OAB total bother score (33 (Q1-Q3:30-35.5) vs 32 (Q1-Q3: 23.5-36, p=0.28)) was observed (Table 1).

UCon neurostimulator significantly reduced the number of voids and UUI episodes in the time-limited stimulation group. In the on-demand stimulation group, number of voids was significant reduced. UUI episodes were reduced by nearly 50% but did not reach statistical significance. This difference between the two stimulation modalities could be explained by a smaller population size in the on-demand stimulation group. Participants assigned to the on-demand stimulation group also had notably more voids and UUI episodes at baseline. Moreover, the on-demand stimulation group had an outlier with a remarkable increase in UUI episodes, to 59 by the fourth stimulation week, compared to 22 UUI episodes per seven days at baseline. 
The effect of each stimulation modality in the present study cannot be evaluated, as participants were assigned to the stimulation modalities based on their symptoms or preferences.

Treatment with the UCon neurostimulator was feasible and safe. These clinical results demonstrated a reduction in voids, UUI episodes and the impact of OAB symptoms on the QoL, indicating promising potential for treating OAB symptoms with DGN stimulation, with the UCon neurostimulator.

Continence 12S (2024) 101510
DOI: 10.1016/j.cont.2024.101510