Multidisciplinary approach for ABI recipients: surgical, electrophysiologic, and behavioral outcomes

Abstract

Objective To describe the multidisciplinary approach implemented at the Medical College of Wisconsin for treating deafness in patients with neurofibromatosis type II (NF2) using the Nucleus 24 auditory brainstem implant (ABI). Study design The ABI protocol at the Medical College of Wisconsin includes microsurgical and endoscopic placement of the electrode pad, electrophysiologic testing in the operating room to ensure optimal placement, and psychophysical/behavioral testing for appropriate stimulation and longitudinal follow-up of the patient. Results To date, five patients have received ABIs and all are active users of their devices. All showed electrically evoked auditory brainstem responses during surgical placement, although they varied in morphology and amplitude. Of a possible 20 active electrodes, patients receive usable auditory stimulation on an average of 15 electrodes. Interfering nonauditory stimulation is present on an average of four electrodes. Pure-tone thresholds range from 20 to 35 dBHL across patients. For two patients who have 1 year of device use, their scores were 65% and 90% on the four-choice spondee (auditory-only). Substantial vowel recognition (Iowa Vowel Test) was observed in two patients who had 1 year of implant use (91% and 81%, auditory and visual) and one patient who had 6 months of implant use (64%, auditory and visual). In addition, patients have provided subjective reports of satisfaction with their devices Conclusion The multidisciplinary approach to auditory brainstem implantation at the Medical College of Wisconsin has been successful in treating deafness in NF2 patients. Proper placement of the electrode and careful programming of the device are crucial for a positive outcome, and require synergy among surgical, electrophysiologic, and clinical disciplines.