Percutaneous Tibial Nerve Stimulation Produces Effects on Brain Activity: Study on the Modifications of the Long Latency Somatosensory Evoked Potentials

Objective: Long-latency somatosensory evoked potentials (LL-SEP) provide information on the function of somatosensory cortical structures. Percutaneous tibial nerve stimulation (PTNS) is indicated in the treatment of lower urinary tract dysfunction. Aim of this study was to evaluate LL-SEP in patients with overactive bladder syndrome (OAB) treated by means of PTNS. Methods: Sixteen female patients with a diagnosis of pharma-coresistant OAB underwent PTNS while eight female patients with the same diagnosis underwent sham stimulation. LL-SEP were performed at baseline and at the end of PTNS or sham stimulation. Peak latency and peak to peak amplitude of P80, P100, and P200 waves were measured. Results: Mean latency of P80, P100, and P200 and mean amplitude of P200 did not show any significant change after both stimulation. Mean amplitude of P80 and P100 waves increased significantly after PTNS while it did not vary after sham stimulation. Conclusion: The P80 and P100 amplitude increase might reflect long-term modifications in synaptic efficiency through the somatosensory pathway. The plastic reorganization of cortical network triggered by peripheral neuromodulation can be hypothesized as a mechanism of action of PTNS. Further studies are needed to correlate LL-SEP modifications after PTNS with the success of the treatment. Neurourol. Urodynam. 28:320-324, 2009. (C) 2008 Wiley-Liss, Inc.