Intraoperative Electrocochleography Audiogram: Correlation With Postoperative Audiometric Results in Patients With Residual Hearing.

OBJECTIVE

To determine whether there is a correlation between intraoperative electrocochleography (ECochG) audiograms and postoperative audiometric air and bone conduction thresholds.

STUDY

DESIGN

Single institution, retrospective cohort study.

SETTING

Tertiary care cochlear implant (CI) center.

PATIENTS: Patients 11 years of age and older (n=12) with pure-tone audiometry thresholds ≤80 dB HL at 500 Hz who received Advanced Bionics CIs completed between 2019 and 2023.

METHODS

Intraoperative ECochG was employed to monitor CI insertion in real-time, in an effort to minimize insertion trauma. ECochG was monitored with acoustic stimulation. Subsequently, intraoperative ECochG audiograms were completed immediately following insertion. Postoperative air and bone conduction audiograms were performed at activation, 1, 3, and 6 months postactivation and were compared with intraoperative ECochG audiograms.

RESULTS

Intraoperative ECochG audiogram was found to be closely associated with both activation ( r =0.45, P =0.005) and 6-month ( r =0.50, P =0.0009) air conduction (AC) audiograms, but not associated with bone conduction (BC) audiograms. An air-bone gap was present at activation and persisted 6 months post activation, with a gradual decline but not closure over time.

CONCLUSION

Intraoperative postinsertion ECochG audiograms can predict long-term AC thresholds in patients undergoing cochlear implantation. Persistent air-bone gaps documented at activation suggest an immediate impact of the electrode array on the conductive component, rather than the effect of delayed scar tissue formation following implantation.