Visual evoked potentials with hemifield pattern stimulation. Their use in the diagnosis of retrochiasmatic lesions.
We measured several parameters of cortical potentials evoked by visual stimulation to produce a profile suggestive of retrochiasmatic lesions. Characteristic abnormal responses included (1) very low amplitude or absent transient visual evoked potentials (T-VEPs) after stimulation of the affected hemifield, (2) reversal of normal pattern amplitude of the T-VEP distribution after stimulation of the affected hemifield, (3) abnormal lateral occipital ratio, (4) absent or very low amplitude steady-state VEPs after stimulation of affected hemifield, and (5) abnormal midoccipital ratio.
D000328:Adult; D001927:Brain Diseases / Q000175:diagnosis* / Q000503:physiopathology; D002544:Cerebral Infarction / Q000175:diagnosis; D004292:Dominance, Cerebral / Q000502:physiology*; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006423:Hemianopsia / Q000503:physiopathology; D006801:Humans; D008297:Male; D009778:Occipital Lobe / Q000503:physiopathology; D009897:Optic Chiasm / Q000503:physiopathology*; D010364:Pattern Recognition, Visual / Q000502:physiology; D010775:Photic Stimulation; D014795:Visual Pathways / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology*