Predictive Value of EABRs in NF2 Adults and Non-NF2 Children

Objective: To compare the predictive value of intraoperative electrically evoked auditory brainstem response (EABR) between NF2 adult ABI recipients and non-NF2 pediatric ABI recipients.
Study design: Retrospective case series.
Setting: Single tertiary academic referral center.
Patients: All ABI recipients from 1994 to 2018, which included 36 NF2 adults and 12 non-NF2 children.
Intervention(s): EABR recordings during ABI placement.
Main outcome measure(s): The morphologies of the intraoperative EABRs were evaluated for the number of waveforms showing a response, the number of positive peaks in those responses, and the latencies of each of these peaks.
Results: 29/36 (80%) adult NF2 patients and 10/12 (83%) children had intraoperative EABR waveforms. 22/29 (76%) of the adult patients and all of the children had ABI devices that stimulated post-operatively. When comparing the waveforms between adults who stimulated and those who did not stimulate, the proportion of total number of intraoperative EABR peaks to total possible peaks was significantly higher for the adults who stimulated than for those who did not (p<0.05). Children had a significantly higher proportion of total number of peaks to total possible peaks when compared to adults who stimulated (p<0.02). Additionally, there were more likely to be EABR responses at the initial stimulation than intraoperatively in the pediatric ABI population (p=0.065).
Conclusions: This study shows that a higher number of total peaks seen on intraoperative EABRs may indicate a higher likelihood of eventual device stimulation, although the predictive value of intraoperative EABR for speech perception outcome requires further study.