The goal of this clinical trial is to learn if using a portable nerve stimulation (TENS) device during daily life works to reduce overactive bladder (OAB) symptoms in adults aged 18 to 65. The main questions it aims to answer are:

• Does using TENS at home during daily activities reduce the number of urgency episodes?
• Does this approach improve bladder symptoms and quality of life as much as clinic-based treatment?

Researchers will compare two ways of using TENS applied to the ankle area (tibial nerve stimulation):

• Group 1 (Clinic-based): Participants will visit the clinic twice a week for 2 weeks and receive 30-minute TENS sessions.
• Group 2 (Ambulatory): Participants will use a portable TENS device at home during their daily routine when they feel the urge to urinate, over a 2 week period.

Both groups will use the same electrical settings (20 Hz frequency, 200 µs pulse width).

Participants will:

• Complete bladder symptom questionnaires before and after the study
• Fill in a 3-day voiding diary to track how often they urinate, urgency episodes, and any leakage
• Answer quality of life questions at the start and at 4 weeks

Overactive bladder (OAB) is a common condition that causes a sudden, strong need to urinate. It may also cause frequent urination during the day and night, and sometimes urine leakage. Transcutaneous tibial nerve stimulation (TTNS) is a safe, non-invasive treatment that uses mild electrical impulses through the skin near the ankle to calm bladder activity. The posterior tibial nerve at the ankle shares the same spinal nerve roots (L4-S3) that control the bladder.

Current TTNS protocols require regular clinic visits on a fixed schedule. This study introduces an ambulatory approach where participants use a portable TENS device in their daily life when urgency symptoms occur, rather than attending scheduled clinic sessions.

This is a prospective, single-center, randomized controlled trial conducted at Başakşehir Çam and Sakura City Hospital, Istanbul, Turkey. A total of 30 to 50 adults aged 18 to 65 with a clinical diagnosis of OAB who have not improved enough with lifestyle changes and behavioral therapy will be enrolled.

Participants will be randomly placed into one of two groups:

Group 1 - Conventional TTNS: Clinic-based sessions, twice per week for 2 weeks (4 sessions total), each lasting 30 minutes.

Group 2 - Ambulatory TTNS: Participants will receive a portable TENS device and use it at home during daily activities when they experience urgency, over a 4-week follow-up period.

Both groups will use the same stimulation settings: 20 Hz frequency and 200 µs pulse width. Two surface electrodes will be placed over the posterior tibial nerve near the inner ankle. The intensity will be set at a comfortable level just below the point that causes muscle movement.

Outcomes will be measured at baseline and at 4 weeks using OAB symptom scores (OAB-V8 and/or OABSS), a 3-day voiding diary (urinary frequency, urgency episodes, incontinence episodes), and quality of life questionnaires. Treatment adherence, patient satisfaction, and any side effects will also be recorded.

Inclusion Criteria:

• Adults aged 18 to 65 years
• Clinical diagnosis of overactive bladder (OAB)
• Working in an office setting or spending most of the day at home, suitable for using a portable TENS device

Exclusion Criteria:

• Pregnancy
• Cardiac pacemaker
• Epilepsy
• Metal implant in the ankle area
• Open wound or skin disease at the electrode site
• Active urinary tract infection
• Neurological disease affecting bladder function
• Previous surgery for urinary incontinence or OAB
• Current anticholinergic or beta-3 agonist use for OAB
• Cognitive impairment preventing proper device use