title: Non-invasive mapping of bilateral motor speech areas using navigated transcranial magnetic stimulation and functional magnetic resonance imaging.
abstract: BACKGROUND
  Navigated transcranial magnetic stimulation (nTMS) is a modern precise method to activate and study cortical functions noninvasively. We hypothesized that a combination of nTMS and functional magnetic resonance imaging (fMRI) could clarify the localization of functional areas involved with motor control and production of speech.
  
  
  METHODS
  Navigated repetitive TMS (rTMS) with short bursts was used to map speech areas on both hemispheres by inducing speech disruption during number recitation tasks in healthy volunteers. Two experienced video reviewers, blinded to the stimulated area, graded each trial offline according to possible speech disruption. The locations of speech disrupting nTMS trials were overlaid with fMRI activations of word generation task.
  
  
  RESULTS
  
  
  
  METHODS
  Speech disruptions were produced on both hemispheres by nTMS, though there were more disruptive stimulation sites on the left hemisphere. Grade of the disruptions varied from subjective sensation to mild objectively recognizable disruption up to total speech arrest. The distribution of locations in which speech disruptions could be elicited varied among individuals. On the left hemisphere the locations of disturbing rTMS bursts with reviewers' verification followed the areas of fMRI activation. Similar pattern was not observed on the right hemisphere.
  
  
  CONCLUSIONS
  The reviewer-verified speech disruptions induced by nTMS provided clinically relevant information, and fMRI might explain further the function of the cortical area. nTMS and fMRI complement each other, and their combination should be advocated when assessing individual localization of speech network.
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland; Department of Radiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland. Electronic address: mervi.kononen@kuh.fi.
authors.forename: Mervi
authors.initials: M
authors.lastname: Könönen
authors.affiliation: Institute of Clinical Medicine, Clinical Neurophysiology, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Niko
authors.initials: N
authors.lastname: Tamsi
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland; Institute of Clinical Medicine, Clinical Neurophysiology, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Laura
authors.initials: L
authors.lastname: Säisänen
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland.
authors.forename: Samuli
authors.initials: S
authors.lastname: Kemppainen
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland.
authors.forename: Sara
authors.initials: S
authors.lastname: Määttä
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland.
authors.forename: Petro
authors.initials: P
authors.lastname: Julkunen
authors.affiliation: Department of Neurology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland.
authors.forename: Leena
authors.initials: L
authors.lastname: Jutila
authors.affiliation: Department of Neurology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland.
authors.forename: Marja
authors.initials: M
authors.lastname: Äikiä
authors.affiliation: Department of Neurology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland; Institute of Clinical Medicine, Neurology, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Reetta
authors.initials: R
authors.lastname: Kälviäinen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Eini
authors.initials: E
authors.lastname: Niskanen
authors.affiliation: Department of Radiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland; Institute of Clinical Medicine, Clinical Radiology, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Ritva
authors.initials: R
authors.lastname: Vanninen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Pasi
authors.initials: P
authors.lastname: Karjalainen
authors.affiliation: Department of Clinical Neurophysiology, Kuopio University Hospital, PO Box 100, 70029 Kuopio, Finland; Institute of Clinical Medicine, Clinical Neurophysiology, University of Eastern Finland, 70211 Kuopio, Finland.
authors.forename: Esa
authors.initials: E
authors.lastname: Mervaala
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007802:Language; D007807:Language Tests; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009483:Neuropsychological Tests; D013060:Speech / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation / Q000009:adverse effects / Q000379:methods*; D055815:Young Adult
keywords: Bilateral speech area mapping; Functional magnetic resonance imaging; Motor speech area; Navigated transcranial magnetic stimulation; Preoperative mapping; nTMS