PD31-09 EFFECTS OF REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION OF THE SUPPLEMENTARY MOTOR AREA AND DORSOLATERAL PREFRONTAL CORTEX ON PELVIC FLOOR MUSCLE ACTIVITY IN PATIENTS WITH OVERACTIVE BLADDER

INTRODUCTION AND OBJECTIVE:
The supplemental motor area (SMA) and dorsolateral prefrontal cortex (dlPFC) are components of the normal bladder control network. Adults with overactive bladder (OAB) have abnormal activity of the SMA and dlPFC during a full bladder which can be normalized following successful therapy. The SMA has a role in motor control of pelvic floor muscles (PFM). Real-time responsiveness of resting PFM activity to repetitive transcranial magnetic stimulation (rTMS) has been shown in urologic chronic pain patients. Effects of rTMS to the SMA on PFM activity are unknown in OAB. It is unknown if multisite rTMS to the SMA and the dlPFC has cumulative effects, altering resting PFM activity. Here, we investigate the effects of multi-session rTMS to the SMA and dlPFC on PFM electromyography (EMG) in adults with OAB.

METHODS:
OAB subjects participated in 5 sessions of rTMS. Neuro-navigation aided in targeting the SMA and dlPFC. At 70-80% of the resting motor threshold, 20 minutes of continuous inhibitory 1 Hz pulses are delivered to the pelvic SMA for 20 minutes (1,200 pulses) and twenty 10 second 5-10 Hz excitatory trains are delivered to the dlPFC over 20 minutes (1,000-2,000) pulses. Peri-anal surface electrodes were used for resting PFM EMG during the first and fifth sessions, with one ground. Denoising, detrending, and bandpass filtering processed the tracings before motor evoked potentials (MEP) amplitudes were computed. The mean amplitude (mV) was assessed during the initial and final 3 minutes of pulses to the SMA and dlPFC.

RESULTS:
Eight PFM-EMG assessments from 5 subjects (1 male, 4 female) were available and analyzed. EMG traces showed single MEPs following each pulse during the SMA protocol. The group average amplitude of MEPs during the initial and final 3 minutes of rTMS sessions is shown in Figure 1. Mean amplitude of the MEPs significantly increased during SMA sessions (p=0.01). No MEPs were detected during pulses to the dlPFC.

CONCLUSIONS:
Low-frequency rTMS to the SMA elicits MEPs of the PFM in real-time which is increased in amplitude over 20 minutes at first and fifth rTMS sessions in OAB. rTMS pulses to the dlPFC did not produce direct responses in PFM activity, but more investigation is needed in a larger sample.