Optically tracked neuronavigation increases the stability of hand-held focal coil positioning: Evidence from "transcranial" magnetic stimulation-induced electrical field measurements

The stability of hand-held coil positioning with neuronavigated versus conventional transcranial magnetic stimulation (TMS) is still underinvestigated Eleven operators naive for neuronavigation were asked to position and maintain a figure-of-eight-shaped coil over a dipole probe placed within of a polystyrene reproduction of the human head and scalp. in correspondence of the right primary motor cortex Ten monophasic magnetic pulses we me delivered at 46% maximal stimulator output (M SO) two different experimental conditions (1) assisted by an optically tracked neuronavigational system. and (2) without neuronavigation With neuronavigated stimulation, both standard deviation and coefficient of variation of the voltages induced in the dipole probe were significantly lower than without neuronavigation Results were confirmed in four operators performing a longer-lasting experiment us tug 50 magnetic pulses in each condition. at an intensity of at 40% MSO Findings show that optically tracked neuronavigation improves the stability of focal coil positioning (C) 2010 Elsevier Inc All rights reserved