Brain stem acoustic evoked potentials recorded from the human mesencephalon.
Near field brain stem evoked potentials (NF-BAEPs) were recorded by means of an intraparenchymatous electrode placed in the right mesencephalon, during a stereotactic-guided biopsy of a tumor. The traces were compared with far field BAEPs (FF-BAEPs) obtained intraoperatively with scalp electrodes. The findings suggest a peripheral origin of wave II, a bilateral source of wave III and a main contralateral source of wave IV, while wave V seems to take origin mainly from the homolateral upper brain stem. Some intraparenchymatous activities do not project to the scalp. The possible impairments of NF-BAEP due to the presence of the tumor and the challenges of unidimensional single electrode recording are discussed.
Landi
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Department of Neurosurgery, S. Bortolo General Hospital, Vicenza, Italy.
Colombo
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F
D000161:Acoustic Stimulation; D000328:Adult; D001932:Brain Neoplasms / Q000503:physiopathology* / Q000601:surgery; D004569:Electroencephalography; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D006801:Humans; D008297:Male; D008636:Mesencephalon / Q000503:physiopathology* / Q000601:surgery