At-Home Transcutaneous Tibial Nerve Stimulation for Overactive Bladder in Rural Women

A total of 38 participants who meet the inclusion criteria will be recruited from clinical sites in three rural Oregon counties: 1) Klamath County, 2) Jefferson County, and 3) Coos County. Potential subjects with overactive bladder (OAB) who are being seen at healthcare clinics including primary care, obstetrics and gynecology, and pelvic floor physical therapy will be informed of this research study. Interested participants will be referred to the study coordinator via a flyer. Participants will be screened by phone and if deemed eligible and elect to participate, they will be consented over the phone/web platform. The participant has the option to sign a paper consent should they not have access to the internet. This will be mailed to them with prepaid postage for return of the signed consent. If a person does not elect to participate, the study team will offer the person information about behavioral modifications for treatment of overactive bladder and/or a referral to a local pelvic floor physical therapist. All communication and patient facing information will be offered in English or Spanish, utilizing Oregon Health \& Science University's (OHSU's) interpreter services for translation from English as described above.

Our intervention focuses on self-implemented at-home transcutaneous tibial nerve stimulation (TTNS) using a transcutaneous electrical nerve stimulation (TENS) unit. The TENS device is a nonsignificant risk device. A TENS unit with preset settings, labeled device, reusable electrodes, a battery, and detailed instructions will be mailed to the participant's designated address. All participants will receive a set of written instructions in the mail with details on skin preparation, application of the two electrodes to their ankle, connection of the electrodes to the TENS unit, standardized stimulation parameters, and adjustment of intensity to perception threshold. The written instructions will contain pictures and graphics that guide correct placement of the electrodes and use of the TENS unit settings. All participants will also be provided with a link to a short video demonstrating the application and use of the TENS unit. The script for this video is submitted with this IRB application.

Our protocol will instruct participants to use the TENS unit to deliver stimulation to the tibial nerve on one ankle for a 30-minute session, three times per week for 12 weeks starting treatment upon receipt of the device. The standardized stimulation parameters include pulse frequency of 10 Hz and pulse width of 200 ms, as used in previous studies. The intensity level is based on the participant's tolerance, ideally just above the perception threshold but not painful. Participants will be contacted by telephone at 2-3 week intervals to check on compliance with the protocol and address any issues. They will be given the study team's contact information to call sooner if questions or issues arise. Participants will also be provided with an electronic or printed 12 week calendar to keep track of completed sessions.

All participants recruited into the interventional study will also be approached and consented for possible involvement in individual interviews at their initial enrollment. Following completion of the intervention, the PI and co-investigator will use purposive sampling to identify 10-20 key informants for one-on-one video and/or audio recorded interviews with a member of the research group. Informants in the study sample are selected by investigators considering several parameters including demographic features, baseline and post-intervention scores on questionnaires from the primary and secondary outcomes previously mentioned, and compliance rate. Key informant interviews will provide insights on participant's unique experiences with self-managed TTNS at home, allowing for determination of patient perceived facilitators and barriers to this intervention. These key topics and themes can be used to inform future practices regarding self-implemented TTNS among rural dwelling patients.

A list of pre-determined, open-ended questions will be asked to each participant addressing different themes. The script and questions for the interview portion will be submitted alongside this proposal. Interviews will be recorded and transcribed verbatim using software licensed through the OHSU library (Dedoose). The software will be utilized to identify key themes emerging from the interview process. Data collection will cease once thematic saturation has been achieved, determined by the PI and co-investigator.