TMS in Neurosurgery: 1 year experience with navigated TMS for preoperative analysis

Objective: Navigated transcranial magnetic stimulation (nTMS) is the only painless non-invasive method that allows for functional testing analogous to the procedure of direct electrocortical stimulation (DCS). The challenge with nTMS is achieving precise, repeatable application of the TMS impulse. We report on our findings with two different nTMS systems and outline the possible error sources. Methods: Initially, a sensor-based navigation system was used for guidance of the coil which allowed projection of the magnetic impulse focus onto the cortical surface as well as visualization of the angle at which the imp…