Short-Term Dorsal Genital Nerve Stimulation Increases Subjective Arousal in Women With and Without Spinal Cord Injury: A Preliminary Investigation.

OBJECTIVES: Female sexual dysfunction (FSD) affects an estimated 40% of women. Unfortunately, FSD is understudied, leading to limited treatment options for FSD. Neuromodulation has shown some success in alleviating FSD symptoms. We developed a pilot study to investigate the short-term effect of electrical stimulation of the dorsal genital nerve and tibial nerve on sexual arousal in healthy women, women with FSD, and women with spinal cord injury (SCI) and FSD. MATERIALS AND METHODS: This study comprises a randomized crossover design in three groups: women with SCI, women with non-neurogenic FSD, and women without FSD or SCI. The primary outcome measure was change in vaginal pulse amplitude (VPA) from baseline. Secondary outcome measures were changes in subjective arousal, heart rate, and mean arterial pressure from baseline. Participants attended one or two study sessions where they received either transcutaneous dorsal genital nerve stimulation (DGNS) or tibial nerve stimulation (TNS). At each session, a vaginal photoplethysmography sensor was used to measure VPA. Participants also rated their level of subjective arousal and were asked to report any pelvic sensations. RESULTS: We found that subjective arousal increased significantly from before to after stimulation in DGNS study sessions across all women. TNS had no effect on subjective arousal. There were significant differences in VPA between baseline and stimulation, baseline and recovery, and stimulation and recovery periods among participants, but there were no trends across groups or stimulation type. Two participants with complete SCIs experienced genital sensations. CONCLUSIONS: To our knowledge, this is the first study to measure sexual arousal in response to short-term neuromodulation in women. This study indicates that short-term DGNS but not TNS can increase subjective arousal, but the effect of stimulation on genital arousal is inconclusive. This study provides further support for DGNS as a treatment for FSD.

Transcutaneous Electrical Nerve Stimulation to Improve Female Sexual Dysfunction Symptoms: A Pilot Study.

OBJECTIVES: To perform a pilot study using transcutaneous electrical nerve stimulation (TENS) on the dorsal genital nerve and the posterior tibial nerve for improving symptoms of female sexual dysfunction (FSD) in women without bladder problems. We hypothesize that this therapy will be effective at improving genital arousal deficits. MATERIALS AND METHODS: Nine women with general FSD completed the study. Subjects received 12 sessions of transcutaneous dorsal genital nerve stimulation (DGNS; n = 6) or posterior tibial nerve stimulation (PTNS; n = 3). Stimulation was delivered for 30 min at 20 Hz. Sexual functioning was evaluated with the female sexual functioning index (FSFI), and surveys were also given on general health, urological functioning, and the Patients' Global Impression of Change (PGIC) after treatment. Surveys were given before treatment (baseline), after 6 and 12 weeks of treatment, and 6 weeks after the completion of stimulation sessions. RESULTS: The average total FSFI score across all subjects significantly increased from 15.3 ± 4.8 at baseline to 20.3 ± 7.8 after six sessions, 21.7 ± 7.5 after 12 sessions, and 21.3 ± 7.1 at study completion (p < 0.05 for all time points). Increases were observed in both DGNS and PTNS subjects. Significant FSFI increases were seen in the subdomains of lubrication, arousal, and orgasm, each of which is related to genital arousal. Bladder and general health surveys did not change across the study. PGIC had a significant increase. CONCLUSIONS: This study provides evidence that transcutaneous stimulation of peripheral nerves has the potential to be a valuable therapeutic tool for women with FSD.

Temporal pattern of stimulation modulates reflex bladder activation by pudendal nerve stimulation.

AIMS: Reflex bladder activation and inhibition by electrical stimulation of pudendal nerve (PN) afferents is a promising approach to restore control of bladder function in persons with lower urinary tract dysfunction caused by disease or injury. The objective of this work was to determine whether bladder activation evoked by pudendal afferent stimulation was dependent on the temporal pattern of stimulation, and whether specific temporal patterns of stimulation produced larger bladder contractions than constant frequency stimulation. METHODS: The mean and maximum contraction pressures evoked by different temporal patterns of stimulation of the dorsal genital branch of the pudendal nerve were measured under isovolumetric conditions in α-chloralose anesthetized cats. A computational model of the spinal neural network mediating the pudendo-vesical reflex was used to understand the mechanisms of different bladder responses to patterned stimulation. RESULTS: The pattern of stimulation significantly affected the magnitude of evoked bladder contractions; several temporal patterns were as effective as regular stimulation, but no pattern evoked larger bladder contractions. Random patterns and patterns with pauses, burst-like activity, or high frequency components evoked significantly smaller bladder contractions, supporting the use of regular frequency stimulation in the development of neural prosthetic approaches for bladder control. CONCLUSIONS: These results reveal that the bladder response to pudendal afferent stimulation is dependent on the pattern, as well as the frequency, of stimulation. The computational model revealed that the effects of patterned pudendal afferent stimulation were determined by the dynamic properties of excitatory and inhibitory interneurons in the lumbosacral spinal cord. Neurourol. Urodynam. 35:882-887, 2016. © 2015 Wiley Periodicals, Inc.

Beneficial carry-over effects of chronic at-home genital nerve stimulation on incontinence in individuals with spinal cord injury: A pragmatic trial.

BACKGROUND: Genital nerve stimulation (GNS) is a promising, but under-researched, alternative treatment for neurogenic detrusor overactivity (NDO) in those with spinal cord injury (SCI). OBJECTIVES: To investigate the urodynamic, quality-of-life (QOL) and carry-over effects of GNS when applied at home for 2 weeks by participants with incomplete SCI and NDO during activities of daily living. METHODS: Seven men and 1 woman participated in this 1-month protocol study. Urodynamic and QOL data were gathered during week 1 (baseline measurements), followed by 2 weeks of daily GNS at home using a portable device. GNS was applied either on-demand or thrice daily, depending on the individual's sensation. At week 4, post-stimulation tests were repeated to record any carry-over effect from the GNS. Participants maintained voiding diaries throughout the study. Assessments were carried out at the end of each protocol period in a randomized order. Clinical procedures were conducted at Taipei Medical University Hospital (Taipei, Taiwan). RESULTS: Everyone completed the study but only 7 of the 8 participants completed their voiding diary. Two weeks after GNS, average cystometric bladder capacity was increased by 30 % compared to baseline (P< 0.05). A 1-week carry-over effect was demonstrated as this capacity remained, on average, 35 % greater than baseline in week 4 after GNS was stopped (P< 0.05). Incontinence frequency significantly decreased by the end of week 3 (P< 0.05) but no significant improvements were recorded for either detrusor pressure or bladder compliance. CONCLUSIONS: Chronic at-home GNS improved cystometric bladder capacity and reduced urinary incontinence for individuals with incomplete SCI and NDO. A carry-over effect of 1 week was observed following GNS treatment. The use of portable GNS treatment that can be applied by the individual at home merits further investigation as alternative treatment for NDO in those with SCI.

Subject-controlled stimulation of dorsal genital nerve to treat neurogenic detrusor overactivity at home.

AIMS: To investigate the effects of subject controlled dorsal genital nerve (DGN) electrical stimulation on neurogenic detrusor overactivity (NDO) in subjects at home. METHODS: Subjects underwent a 5-day study at home with DGN stimulation. Stimulation was provided with surface electrodes placed either on the dorsal penile shaft in males and on or close to the clitoris in females. The days 1 and 5 were with no stimulation whereas days 2-4 were with stimulation. Two urodynamic studies were performed at the beginning and at the end of the study. A bladder diary was obtained. RESULTS: Eleven subjects with NDO and with urge incontinence were included. One subject stopped the protocol before the end of the 5-day trial and two did not undergo the second urodynamic study. The subjects showed a statistically significant increase in bladder capacities compared to baseline (P = 0.047). Mean volume per day voided significantly increased over the study within the subjects. Differences between day 1 and day 5 were statistically significant (P = 0.028). CONCLUSIONS: The feasibility and the globally positive outcomes of the study indicate that the stimulation of the dorsal genital nerve can be an option for the treatment of the NDO.

Acute dorsal genital nerve stimulation increases subjective arousal in women with and without spinal cord injury: a preliminary investigation.

Introduction: Female sexual dysfunction (FSD) impacts an estimated 40% of women. Unfortunately, female sexual function is understudied, leading to limited treatment options for FSD. Neuromodulation has demonstrated some success in improving FSD symptoms. We developed a pilot study to investigate the short-term effect of electrical stimulation of the dorsal genital nerve and tibial nerve on sexual arousal in healthy women, women with FSD, and women with spinal cord injury (SCI) and FSD. Methods: This study consists of a randomized crossover design in three groups: women with SCI, women with non-neurogenic FSD, and women without FSD or SCI. The primary outcome measure was change in vaginal pulse amplitude (VPA) from baseline. Secondary outcome measures were changes in subjective arousal, heart rate, and mean arterial pressure from baseline. Participants attended one or two study sessions where they received either transcutaneous dorsal genital nerve stimulation (DGNS) or tibial nerve stimulation (TNS). At each session, a vaginal photoplethysmography sensor was used to measure VPA. Participants also rated their level of subjective arousal and were asked to report any pelvic sensations. Results: We found that subjective arousal increased significantly from before to after stimulation in DGNS study sessions across all women. TNS had no effect on subjective arousal. There were significant differences in VPA between baseline and stimulation, baseline and recovery, and stimulation and recovery periods among participants, but there were no trends across groups or stimulation type. Two participants with complete SCIs experienced genital sensations. Discussion: This is the first study to measure sexual arousal in response to acute neuromodulation in women. This study demonstrates that acute DGNS, but not TNS, can increase subjective arousal, but the effect of stimulation on genital arousal is inconclusive. This study provides further support for DGNS as a treatment for female sexual dysfunction.

Subject-Controlled, On-demand, Dorsal Genital Nerve Stimulation to Treat Urgency Urinary Incontinence; a Pilot.

OBJECTIVES: To evaluate the effect of subject-controlled, on-demand, dorsal genital nerve (DGN) stimulation on non-neurogenic urgency urinary incontinence (UUI) in a domestic setting. MATERIALS AND METHODS: Non-neurogenic patients >18 years with overactive bladder symptoms and UUI were included. Exclusion criteria were mainly stress urinary incontinence. Patients underwent 1 week of subject-controlled, on-demand, DGN stimulation, delivered by a percutaneously placed electrode near the DGN connected to an external stimulator (pulse-rate 20 Hz, pulse-width 300 µs). Patients activated the stimulator when feeling the urge to void and stimulated for 30 s. The amplitude was set at the highest tolerable level. A bladder diary including a severity score of the UUI episodes/void (scores: 0 = none, 1 = drops, 2 = dashes, 3 = soaks) and a padtest was kept 3 days prior to, during, and 3 days after the test period. The subjective improvement was also scored. RESULTS: Seven patients (4 males/3 females) were enrolled, the mean age was 55 years (range 23-73). Six completed the test week. In the remaining patient the electrode migrated and was removed. 5/6 finalized the complete bladder diary, 1/6 recorded only the heavy incontinence episodes (score = 3). 4/6 completed the padtest. In all patients who finalized the bladder diary the number of UUI episodes decreased, in 3/5 with ≥60%. The heavy incontinence episodes (score = 3) were resolved in 2/6 patients, and improved ≥80% in the other 4. The severity score of the UUI episodes/void was improved with ≥ 60% in 3/5 patients. The mean subjective improvement was 73%. CONCLUSION: This feasibility study indicates that subject-controlled, on-demand DGN stimulation using a percutaneously placed electrode is possible over a longer time period, in a home setting, with a positive effect on non-neurogenic overactive bladder symptoms with UUI. Although the placement is an easy procedure, it is difficult to fixate the electrode to keep it in the correct position. Improvements in hardware, like a better fixated electrode and an easy to control stimulator, are necessary to make SODGNS a treatment possibility in the future.