Abstract Introduction Electrically evoked auditory brainstem responses provide reliable clinical information to assist professionals in the auditory rehabilitation of cochlear implant users. Objective This study aimed to investigate intraoperative evoked auditory brainstem response recordings in Evo®-cochlear implant electrode array recipients and its correlation with their behavioral levels and auditory performance. Methods This is a retrospectivey study. Intraoperative evoked auditory brainstem responses were recorded in adult Evo®-cochlear implant electrode array recipients. Wave V latencies, amplitudes and interpeak III-V intervals were recorded in three different electrode locations and compared to the sentence recognition scores obtained from subjects after six months of device use. Evoked auditory brainstem responses thresholds were also recorded and compared to the behaviorally determined levels of the subjects in the sound processor activation. Results Evoked auditory brainstem responses thresholds were significantly correlated with both, behavioral T- and C-levels and they were recorded at audible electrical stimulation levels in all subjects. There was a significant correlation between interpeak III-V interval recorded in the apical electrode and sentence recognition scores of the subjects. Conclusions Intraoperative evoked auditory brainstem responses can be used to establish audible levels for fitting the sound processor in Evo®-cochlear implant recipients and it could help professionals to plan further actions aiming to improve their auditory performance.

Resumo Introdução Os potenciais auditivos de tronco encefálico evocados eletricamente fornecem informações clínicas confiáveis que auxiliam no processo de reabilitação auditiva de usuários de implante coclear. Objetivo Investigar o registro intraoperatório dos potenciais auditivos de tronco encefálico evocados eletricamente em usuários do feixe de eletrodos Evo® e sua correlação com os níveis comportamentais e desempenho auditivo dos indivíduos. Método Estudo retrospectivo. Os potenciais auditivos de tronco encefálico intraoperatórios foram registrados em usuários adultos de implante coclear com feixe de eletrodos Evo®. As latências e amplitudes da onda V e os intervalos interpico III-V foram registrados em três diferentes eletrodos e comparados às pontuações de reconhecimento de sentenças após 6 meses de uso do implante coclear. Os limiares dos eABRs foram comparados aos níveis comportamentais dos indivíduos na ativação do processador de som. Resultados Os limiares do eABR foram significativamente correlacionados aos níveis comportamentais T e C e registrados em níveis de estimulação elétrica audíveis em todos os indivíduos. Houve uma correlação significativa entre o intervalo interpico III-V no eletrodo apical e a pontuação de reconhecimento de sentenças dos indivíduos. Conclusões O eABR intraoperatório pode ser usado para estabelecer níveis audíveis de estimulação elétrica na ativação do processador sonoro em usuários de implante coclear‐Evo® e pode auxiliar os profissionais no planejamento de ações visando melhorar o desempenho auditivo nesses pacientes.

Abstract Introduction The preservation of residual hearing is currently an important challenge for cochlear implant surgeries. Indeed, if patients exhibit functional hearing after cochlear implantation, they can benefit from the combination of acoustical stimulation, usually in the low-frequencies and electrical stimulation in the high-frequencies. This combined mode of stimulation has proven to be beneficial both in terms of speech perception and of sound quality. Finding the right procedures for conducting softsurgeries and designing electrode arrays dedicated to hearing preservation is an open issue. Objective The objective of this study is to evaluate the combination of a soft-surgery procedure implicating round-window insertion and the use of dexamethasone and hyaluronic acid during surgery, with the use of a specifically designed straight soft electrode array, on hearing preservation in patients with functional hearing in the low frequencies. Methods This pre-clinical trial was conducted on seven patients with residual hearing in the low frequencies. The surgical method used employed a round window insertion and the use of topical dexamethasone. Results The soft-surgery protocol could be successfully followed in five patients. In this group, the average hearing threshold shift compared with pre-operative values was of 18.7 þ/ 16.1 dB HL up to 500 Hz and 15.7 þ/ 15.1 up to 1 kHz, demonstrating satisfying levels of hearing preservation. Conclusion We were able to demonstrate the possibility of preserving residual hearing in most of the patients using the EVO electrode. Significant residual hearing preservation levels were was obtained when a soft surgical approach involving round window insertion, dexamethasone and hyaluronic use during the surgery.