Objectives: The aim of this study was to investigate whether electrical auditory brainstem responses (eABR) obtained during cochlear implantation (CI) can predict CI outcomes. We also aimed to assess whether eABR can be used to select patients for auditory brainstem implantation (ABI).
Methods: The study was retrospective. The latencies and quality of the eABR waveforms from adult patients implanted with CI in Uppsala from 2011 to 2013 (n = 74) and four children with severe cochlear abnormalities were analyzed. Speech perception was assessed by postoperative monosyllabic word (MS-word) recognition. A score was constructed for each patient based on wave II, III and V patency.
Results: Wave V for the mid- and low-frequency regions on the implant was the most robust. eABR latencies increased towards base stimulation of the cochlea. Significant latency shifts occurred in wave V from the low- to high-frequency regions on the implant (P** < 0.01) and from the mid- to high-frequency regions on the implant (P** < 0.01). No correlations were found between wave V latency, wave V-III interval, waveform score, and MS-word scores. A negative eABR always predicted a negative outcome. Among the patients with negative outcomes, 75% had eABRs.
Conclusions: Implant electrical auditory brainstem recordings can be used (eABRs wave V) to predict a negative functional outcome. Low-frequency wave V was observed in all patients with successful CI outcomes. Patients for whom eABR waveforms were completely absent had unsuccessful CI outcomes.
