Brainstem Auditory evoked potentials (BAEPs) are very small electrical voltage potentials which are recorded in response to an auditory stimulus from electrodes placed on the scalp. They reflect neuronal activity in the auditory nerve, cochlear nucleus, superior olive and inferior colliculus of the brainstem. They typically have a response latency of no more than six milliseconds with an amplitude of approximately one millivolt. Due to their small amplitude 500 or more repetitions of the auditory stimulus are required in order to average out the random background electrical activity. Although it is possible to obtain a BAEP to a pure tone stimulus in the hearing range a more effective auditory stimulus contains a range of frequencies in the form of a short sharp click.

Long and Allen reported the abnormal BAEPs in an alcoholic woman who recovered from Ondine's curse

Ondine's curse

Ondine's Curse, also called congenital central hypoventilation syndrome or primary alveolar hypoventilation, is a respiratory disorder that is fatal if untreated...

. These investigators hypothesized that their patient's brainstem was poisoned, but not destroyed, by her chronic alcoholism.