Objective: To study the feasibility and clinical applicability of preoperative, transtympanic electrically evoked auditory brain-stem response (EABR) in a pediatric patient population with cochlear implants.
Design: A descriptive study using repeated measures analyses of variance to determine if EABR measures were affected by response configuration or cochlear status.
Setting: The operating room before cochlear implant surgery.
Patients: A population-based sample of 43 patients aged 2.5 to 14.5 years who were candidates for cochlear implantation.
Intervention: Stimuli consisting of brief balanced biphasic current pulses were provided by a transtympanically placed promontory needle electrode; EABR was recorded with subdermal needle electrodes on the forehead and contralateral mastoid.
Main outcome measure: Presence or absence of postoperative electrical excitability with a cochlear implant.
Results: Electrically evoked auditory brain-stem responses were available from 41 of the 43 patients tested. Mean EABR threshold was 406.5 microA (SD = 118.1) for 31 patients with patent cochleas and 472 microA (SD = 91) for 10 patients with cochlear ossification. Mean wave V latency at threshold was 4.69 milliseconds (SD = 0.57).
Conclusion: Preoperative EABR is an integral component of the preoperative selection process for pediatric patients with cochlear implants.