Reappearance of brain-stem auditory evoked potentials after surgical treatment of a brain-stem hemorrhage: contributions to the question of wave generation.
We report on a patient suffering a spontaneous hemorrhage primarily located in the right brain-stem; surgical correction of this led to a substantial improvement in clinical deficits. Brain-stem auditory evoked potentials (BAEPs) were recorded on postoperative days 18, 30, 55 and 205. Waves II through V were initially undetectable on stimulation of the damaged side, whereas the absence of peak V was the only abnormality seen on left-side stimulation. With the regression of the right lower mid-pontine deficits, the right waves gradually reappeared and normalized progressively. On the last recording, only a left wave V abnormality persisted. At that time, the patient had a moderate left hemisyndrome due to a circumscribed right upper pontine-midbrain lesion. Therefore, it can be suggested that the first 4 waves of BAEPs mainly originate in the ipsilateral pons, and the Vth in the contralateral higher regions.
Department of Neurology, General Hospital, Treviso, Italy.
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G
Zanette
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A
Carteri
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S
Cusumano
D000161:Acoustic Stimulation; D001933:Brain Stem / Q000503:physiopathology / Q000601:surgery*; D002543:Cerebral Hemorrhage / Q000601:surgery*; D002648:Child; D005072:Evoked Potentials, Auditory; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D008475:Median Nerve / Q000503:physiopathology