Localizing brain stem lesions with brain stem auditory evoked potentials

Based on a survey of brain stem auditory evoked potentials (BAEPs) in animals and humans with localized brain stem lesions compared to the recognizability of BAEP components in normal materials, it was concluded that BAEP examination might localize lesions to a high or low level and diffusely within the brain stem. In 155 patients with multiple sclerosis, vascular disorders or other lesions from a neurological department, the involvement of the brain stem was clinically estimated to be negative, situated at a high or low level or diffuse. Correlation between location of the lesions assessed by clinical versus BAEP examination showed correspondence between negative and diffusely abnormal findings, but not with regard to levels within the brain stem. CT-scanning similarly failed to localize lesions to various levels. This was probably due to poorly circumscribed or widespread lesions. The main value of BAEP in neurological patients was to establish clinically silent lesions, especially in patients with multiple sclerosis and only spinal signs.