Selective unilateral absence or attenuation of wave V of brain-stem auditory evoked potentials with intrinsic brain-stem lesions.

The contribution of ipsilateral and contralateral auditory brain-stem structures to the generation of wave V of brain-stem auditory evoked potentials is a controversial subject. We describe two cases with an intrinsic brain-stem lesion that involved the lateral lemniscus unilaterally in the middle and upper pons. The focal nature of the auditory structures was confirmed by detailed neuropathologic data in one case and by magnetic resonance scans in the other one.