title: Motor field sensitivity for preoperative localization of motor cortex.
abstract: OBJECTIVE
  In this study the role of magnetic source imaging for preoperative motor mapping was evaluated by using a single-dipole localization method to analyze motor field data in 41 patients.
  
  
  METHODS
  Data from affected and unaffected hemispheres were collected in patients performing voluntary finger flexion movements. Somatosensory evoked field (SSEF) data were also obtained using tactile stimulation. Dipole localization using motor field (MF) data was successful in only 49% of patients, whereas localization with movement-evoked field (MEF) data was successful in 66% of patients. When the spatial distribution of MF and MEF dipoles in relation to SSEF dipoles was analyzed, the motor dipoles were not spatially distinct from somatosensory dipoles.
  
  
  CONCLUSIONS
  The findings in this study suggest that single-dipole localization for the analysis of motor data is not sufficiently sensitive and is nonspecific, and thus not clinically useful.
authors.affiliation: Department of Neurology, Stanford Hospital and Clinics, Stanford, California, USA.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Lin
authors.forename: Mitchel S
authors.initials: MS
authors.lastname: Berger
authors.forename: Srikantan S
authors.initials: SS
authors.lastname: Nagarajan
mesh_terms: D001931:Brain Mapping / Q000379:methods*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000556:secondary / Q000601:surgery*; D002540:Cerebral Cortex / Q000503:physiopathology / Q000601:surgery*; D004292:Dominance, Cerebral; D019054:Evoked Potentials, Motor / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005910:Glioma / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D015225:Magnetoencephalography; D009043:Motor Activity / Q000502:physiology; D009044:Motor Cortex / Q000503:physiopathology*; D011300:Preoperative Care; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013003:Somatosensory Cortex / Q000503:physiopathology; D014110:Touch / Q000502:physiology