Initial Experience with Electrocochleography Used in Clinical Routine: Correlations with Speech Perception Outcomes in Adults

Electrocochleography (ECochG) has received increased interest in the recent years, especially during cochlear implant (CI) electrode insertion and postoperative predictions of outcome. The Advanced Bionics (AB) system is capable of measuring ECochGs via the intra-cochlear electrode array for an acoustically delivered low-frequency sinusoidal stimulus. The aim of this case series presentation was to evaluate clinical feasibility and satisfaction in EAS patients with recordable ECochG signals.

Subjects were adults receiving either the AB HiResUltra SlimJ or Mid-Scala electrode arrays. ECochG responses to tone bursts were recorded during insertion of the electrode array and repeated at 1,3 & 6 months post activation. After initial activation, the electro-acoustic (EAS) stimulation of the CI was programmed in all subjects and compared to electric stimulation only. Speech perception outcomes were monosyllabic words presented at 65 and 80 dB SPL and an adaptive speech in noise test.

As this is an ongoing study, preliminary results reveal that ECochG signals are not measurable in all patients with residual hearing. ECochG signals, when detectable during surgery remain stable and are well correlated to post-operatively measured audiograms. Further results will be presented to quantify these findings.

Initial experience shows ECochG to be practical to apply both intra- and post-operatively. Further recordings are required to determine whether differences between electrode array location can be seen.