Brain stem auditory evoked potentials as a tool in the clinical assessment of children with posterior fossa tumors.

The use of brain stem auditory evoked potentials (BAEP) as a diagnostic modality in children with posterior fossa neoplasms is described. Thirty-one patients were examined; their diagnoses were medulloblastoma (12), brain stem glioma (9), cerebellar astrocytoma (6), and ependymoma (4). Distinct differences in the type and severity of waveform abnormalities were observed among the different tumor types, possibly related to location and invasiveness. Medulloblastomas frequently demonstrate normal waveforms, while brain stem gliomas demonstrate severe disruption of BAEP patterns. Ependymomas may result in a variety of abnormal studies, while cerebellar astrocytomas induce mild abnormalities or result in a normal exam. The use of brain stem auditory evoked potentials in the diagnosis of pediatric brain tumors, as well as the underlying mechanisms of the abnormalities, is discussed.