Active_comparator: Posterior Tibial Nerve Stimulation (PTNS)

Women randomized to the PTNS will be scheduled for sessions once weekly for 30 minutes, for 12 weeks total. The patient sits reclined with their legs elevated on a foot rest. After alcohol swab, a 34 gauge needle is inserted percutaneously 5 cm cephalad to the medial malleolus of the right or left ankle (patient's choice) at a 60 degree angle. A surface electrode is placed on the medial ipsilateral heel. The needle and electrode are connected to a low voltage (9V) electrical stimulator. Stimulation current with a fixed frequency of 20 Hz and a pulse width of 200 μsec is increased until flexion of the big toe or fanning of all toes visualized, or until the woman reports a tingling sensation across the heel or sole of the foot. The current is then set to the highest level of tolerable to the patient (0-10 mA) and then she undergoes therapy for 30 minutes.

Experimental: Home transcutaneous electrical nerve stimulation (TENS)

Women randomized to the TENS group will be asked to purchase a TENS 7000 device (estimated cost $30) and will administer self-treatment at home, daily for 20 minutes, for 12 weeks total.~TENS treatment will be performed as follows (adapted from the most common setting from a s systematic review of TENS for OAB):~\- Surface electrodes, 2 x 2 in diameter, will be placed 5 cm cephalad to the medial malleolus of the right or left ankle (patient's choice). The second surface electrode is placed on the medial aspect of the ipsilateral calcaneus. The electrodes are connected to the TENS device with pre-set settings.~Women will complete 20-minute daily TENS treatment for 12 weeks total.