ELECTRICALLY EVOKED AUDITORY BRAIN-STEM RESPONSE - REFRACTORY PROPERTIES AND STRENGTH-DURATION FUNCTIONS

The electrically evoked auditory brainstem potential (EABR) was recorded in users of both the Nucleus cochlear implant and the Ineraid cochlear implant. The refractory properties of the EABR were evaluated by measuring the response amplitude to a two-pulse stimulus where the interpulse interval was varied. The threshold of response for a single pulse stimulus was also measured as a function of the duration of the biphasic pulse. These strength-duration functions were then used to calculate an EABR chronaxie measure. Both of these measures showed a similar range for the monopolar stimulation used with the Ineraid implant and the bipolar stimulation used with the Nucleus implant. Neither for these two measures of the temporal response properties showed any clear relationship to the ability of individual subjects to perform on a speech perception task.