title: Retrospective review of MEG visual evoked hemifield responses prior to resection of temporo-parieto-occipital lesions.
abstract: Visual evoked cortical magnetic field (VEF) waveforms were recorded from both hemifields in 21 patients with temporo-parieto-occipital mass lesions to identify preserved visual pathways. Fifteen patients had visual symptoms pre-operatively. Magnetoencephalographic (MEG) VEF responses were detected, using single equivalent current dipole (ECD), in 17/21 patients studied. Displaced or abnormal responses were seen in 15 patients with disruption of pathway in one patient. Three of 21 patients had alterations in the surgical approach or the planned resection based on the MEG findings. The surgical outcome for these three patients suggests that the MEG study may have played a useful role in pre-surgical planning.
authors.affiliation: Department of Neurology, Henry Ford Health System, Neuromagnetism Lab, Detroit, MI 48202, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Grover
authors.forename: S M
authors.initials: SM
authors.lastname: Bowyer
authors.forename: J
authors.initials: J
authors.lastname: Rock
authors.forename: M L
authors.initials: ML
authors.lastname: Rosenblum
authors.forename: K M
authors.initials: KM
authors.lastname: Mason
authors.forename: J E
authors.initials: JE
authors.lastname: Moran
authors.forename: B J
authors.initials: BJ
authors.lastname: Smith
authors.forename: G L
authors.initials: GL
authors.lastname: Barkley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000503:physiopathology* / Q000601:surgery*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D012189:Retrospective Studies