Hearing Preservation Outcomes With a Mid-Scala Electrode in Cochlear Implantation.

OBJECTIVE

To evaluate hearing preservation (HP) outcomes in adult cochlear implant recipients with a mid-scala electrode.

SETTING

Tertiary academic center.

PATIENTS

Adult patients implanted with a mid-scala electrode between May 2013 and July 2015.

INTERVENTIONS

Cochlear implantation.

MAIN OUTCOME MEASURE(S): Age, sex, surgical approach, residual hearing changes post cochlear implantation, HP rates using different published classifications, and speech perception scores.

RESULTS

Fifty ears for 47 patients (mean age, 58.2 yr; range, 23-86) were implanted with the electrode. Recognizing that not all patients were true HP candidates and/or underwent generally accepted HP surgical techniques, 39 ears had preoperative low-frequency hearing (audiometric threshold ≤ 85dB HL at 250Hz), 24 preserved acoustic hearing postoperatively (75.0%). Patients who had preserved acoustic hearing were implanted via round window (N = 18), extended round window (N = 4), or via cochleostomy (N = 2) approaches. Mean threshold elevation for low-frequency pure-tone average (125, 250, and 500  Hz) was 20.2  dB after surgery. 43.8% of patients had aidable low-frequency hearing at activation, 30.0% at 6-months postoperatively, and 30.8% 1-year postopera tively. Using a formula outlined by Skarzynski and colleagues, at 6-months postoperatively, 15.0% of patients had complete HP, whereas 40.0% had partial HP. At 1-year, these percentages decreased to 0% and 38.5%, respectively. Age, type of approach, and perioperative steroid use were not correlated with HP outcomes at activation and 6-months postoperatively (p > 0.05).

CONCLUSION

The mid-scala electrode evaluated allows preservation of low-frequency hearing in patients undergoing cochlear implantation at rates and degrees of preservation close to other reports in the cochlear implant literature.