The overall goal of this research is to determine the efficacy of a sham for posterior tibial nerve stimulation (PTNS). This novel design is needed in order to have a sham treatment that is similar to the actual treatment. The PTNS is used to treat urgency and frequency in people with overactive bladder (OAB). Until research is done using a sham component, we are unable to ascertain if the current use of PTNS is due to a placebo effect.

Subjects will be healthy volunteers who are recruited by word of mouth. At their office visit with the Nurse Practitioner (NP), the subject's history and medication list will be reviewed.

The NP will randomize subjects into groups: one group with the PTNS on the right and sham on the left; the other group with the PTNS on the left and sham on the right. There will be a maximum of 30 subjects tested, and up to 50 people screened. The subjects will have 1 session for the testing of the PTNS vs sham that will include 15 minutes of stimulation as noted below. All participants will be blinded to the therapy they receive as described below.

• Device: Posterior Tibial Nerve Device
• Device: Sham

• Active Comparator: Subjects will have their leg and foot draped to remain blinded to the test. They will be in a supine position with the knees abducted and flexed. The medial aspect of the lower extremity is palpated and a needle insertion site is identified. Between the posterior margin of the tibia and the soleus muscle, an acupuncture-like needle is inserted. An adhesive grounding pad is placed on the bottom of the foot just below the smallest toe. The needle and grounding pad are connected to the stimulator and the stimulation is increased as tolerated.
• Sham Comparator: Since subjects with the PTNS will feel foot stimulation, the sham was devised to mimic this feeling without the tibial nerve being stimulated. Again the leg and foot will be draped and out of view from the subject. The medial aspect of the lower extremity is palpated (Figure 4) and the tibial nerve site is identified approximately 5 cm cephalad from the medial malleolus. A Streitberger needle is used at the tibial nerve insertion site to simulate needle placement without puncturing the skin. The needle will be taped in place as in the PTNS procedure. The "grounding pad" will be a gel electrode pad from a TENS unit device that is placed on the bottom of the foot just below the smallest toe.

Inclusion Criteria:

• Male and female subjects >18 years of age
• Female subjects will be menopausal, or have had a tubal ligation or hysterectomy.
• Capable of giving informed consent
• Capable and willing to follow study related procedures

Exclusion Criteria:

• Pregnancy
• InterStim
• Bion
• TENS
• The subject is deemed unsuitable for enrollment in this study by the investigators based on their history or physical examination (including bleeding disorders)