Initial Experience with Electrocochleography Used in Clinical Routine: Correlations with Speech Perception Outcomes in AdultsAdvanced Bionics
23 April 2019 (online)
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. This information is used as feedback to the surgeon during insertion of the electrode array. Furthermore, these measurements can be performed postoperatively. The aim of this case series presentation was to evaluate clinical feasibility and satisfaction in EAS patients with recordable ECochG signals.
ECochG signals in 10 subjects with residual hearing receiving either the AB HiResUltra SlimJ or Mid-Scala electrode arrays was measured during insertion. After complete insertion, ECochG responses to tone bursts at 125, 250, 500, 1 kHz and 2 kHz were recorded and an assumption of threshold made via an implemented algorithm. The threshold estimation procedure was repeated at 1, 3 & 6 months post activation. After initial activation, the electro-acoustic (EAS) stimulation of the CI was programmed in subjects with remaining residual hearing. Speech perception outcomes were measured using monosyllabic words presented at 65 and 80 dB SPL.
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.
Initial experience shows ECochG to be practical to apply both intra- and post-operatively. Further recordings are required to determine whether ECochGs remain stable over the fitting process within the first year.