Update of ABI Outcomes in Non-tumor Adults

Objective The traditional indication for auditory brainstem implants (ABIs) is neurofibromatosis type 2 (NF2) in subjects older than 12 years. In our department, the indications for ABIs have been extended to non-tumor children and adults with cochlear or cochlear nerve injuries or malfunctions who would not benefit from a cochlear implant. The results obtained in non-tumor adults are reported in this study. Methods In our department, from April 1997 to February 2008, ABIs have been implanted in a total of 114 patients (83 adults and 31 children) for different tumor and non-tumor diseases. 15 patients out of 114 have elsewhere previously had a CI with no sound detection. The retrosigmoid-transmeatal approach was used in all tumor patients and the retrosigmoid approach was used in all non-tumor patients. Results All patients had a functioning implantation, and reported auditory sensations with activation of various numbers of electrodes. At 1 year after implantations, non-tumor adults scored from 10% to 100% in open set speech perception tests (average 57%), and tumor patients scored from 5% to 30% (average 11%). The difference between these results is statistically significant (p < 0.01). Conclusions Hearing outcomes are better in non-tumor than tumor patients, with a significant number of non-tumor patients that are able to understand speech at a level comparable to that of the most successful cochlear implant users, including conversational telephone use.