title: Optically tracked neuronavigation increases the stability of hand-held focal coil positioning: evidence from "transcranial" magnetic stimulation-induced electrical field measurements.
abstract: The stability of hand-held coil positioning with neuronavigated versus conventional transcranial magnetic stimulation (TMS) is still underinvestigated. Eleven operators naïve 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 were delivered at 46% maximal stimulator output (MSO) in 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 using 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.
authors.affiliation: Unità Operativa di Neurologia dell'Azienda Sanitaria di Firenze, Ospedale Piero Palagi, Firenze, Italy. cincotta@unifi.it
authors.forename: Massimo
authors.initials: M
authors.lastname: Cincotta
authors.forename: Fabio
authors.initials: F
authors.lastname: Giovannelli
authors.forename: Alessandra
authors.initials: A
authors.lastname: Borgheresi
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Balestrieri
authors.forename: Lucia
authors.initials: L
authors.lastname: Toscani
authors.forename: Gaetano
authors.initials: G
authors.lastname: Zaccara
authors.forename: Filippo
authors.initials: F
authors.lastname: Carducci
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Viggiano
authors.forename: Simone
authors.initials: S
authors.lastname: Rossi
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods; D005260:Female; D006257:Head / Q000033:anatomy & histology; D006801:Humans; D008875:Middle Aged; D008953:Models, Anatomic; D056888:Patient Positioning; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation / Q000379:methods; D055815:Young Adult