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August 1985

Auditory Brain-Stem Potentials With Unilateral Pontine Hemorrhage

Author Affiliations

From the Neurology and Medical Research Service, Veterans Administration Medical Center and the Department of Neurology, University of Florida College of Medicine (Drs Hammond, Wilder, and Goodman), and the Department of Pathology, University of Florida (Dr Hunter), Gainesville.

Arch Neurol. 1985;42(8):767-768. doi:10.1001/archneur.1985.04210090031009

• Although there have been extensive anatomical and physiological studies in animals, the actual neural sources, or even the laterality, of some components of auditory brain-stem evoked potentials in humans are uncertain. We studied these responses in a 56-year-old patient who had a clearly demarcated pontine hemorrhage on the right side. The patient Was somnolent, with dense left hemiplegia and signs of involvement of right cranial nerves V, VI, and VII. Stimulation of the left ear (ie, contralateral to the lesion) evoked a normal series of waves with clearly resolved positive components Peaking at 2.0, 3.3, 4.8 (wave IV), and 6.0 ms (wave V). Stimulation of the right ear (ie, ipsilateral to the lesion) evoked only waves I, III, and IV. These results suggest that a pathway ipsilateral to the stimulated ear is necessary and sufficient for generation of auditory wave V and that wave IV is generated in bilateral pathways.