The purpose of this study is to evaluate the safety of an experimental device called the FemPulse System and determine how well it works in the treatment of overactive bladder (OAB) symptoms for women. OAB is a common medical problem and its symptoms may include feelings of urgency to urinate, frequent urination, incontinence, and the need to wake and pass urine at night. The FemPulse System consists of a vaginal ring, hand-held remote control, and charger. The vaginal ring is inserted into the upper vagina, near the cervix and delivers electrical stimulation therapy (pulses) to nerves that control the bladder and can potentially improve bladder function. Participants will be randomly assigned to 1 of 2 groups: the device group or medication group. In the device group, they will receive and use the FemPulse System for up to 12 months. In the medication group, they will receive a medication called tolterodine, extended release, a commonly used OAB medication that is approved by the U.S. Food and Drug Administration (FDA). Those in the medication group may choose to end their participation at 6 months or choose to receive the device and continue participation for another 7-8 months.