Electrically Induced Auditory Brainstem Response as a Clinical Tool in Estimating Nerve Survival

Nerve survival estimates in totally deaf ears of cats and humans can be easily obtained by auditory brainstem responses to electrical stimulation at the round window. In humans, electrically induced auditory brainstem responses require considerably more current than concurrently observed perceptual thresholds and “maximum loudnesses,” and there is much variability from patient to patient. In cats, in which we also compared efficacy of stimulation sites, preliminary data analysis suggests that the scala tympani is clearly much more efficient than the round window, and the round window better than the promontory in ears with large populations of ganglion cells. In ears with no or nearly no ganglion cells, scala tympani and round window stimulations are about equal.