Preimplant Hearing Threshold: An Important Predictor of Hearing Preservation in Cochlear Implantation With Lateral Wall Electrodes

Abstract

Objective: To evaluate the outcomes and association factors of long-term hearing preservation (HP) in cochlear implantation with lateral wall (LW) electrode arrays. Study Design: Retrospective case review. Setting: Tertiary academic center. Patients: Thirty-four consecutive ears from 32 patients with a ≤ 80 dB HL preoperative low-frequency pure-tone average of 250 to 500 Hz were included. Intervention: Cochlear implantation with LW electrode arrays and the intention of achieving HP. Main Outcome Measures: HP classifications according to the HEARRING group and functional HP methods (≤ 85 dB HL of pure-tone threshold at 250 Hz) at 1 year postoperatively. Results: Based on the HEARRING classification, complete, partial, and minimal HP was achieved in 7 ears (21%), 12 ears (35%), and 4 ears (12%), respectively. Under functional classification, 14 ears (41%) exhibited functional hearing after surgery. The average threshold shift was 17.1 dB HL (SD = 16.9 dB HL). Among various clinical features, a ≤ 60 dB HL preimplant pure-tone threshold of 250 Hz was associated with HP outcome in both classifications (OR = 12.95, 95% CI = 1.29–130.01, p = 0.029 in HEARRING classification; OR = 14.36, 95% CI = 1.07–191.40, p = 0.044 in functional classification). The following parameters were not associated with HP (p > 0.05): patient demographics, surgical aspects (insertion route and depth), electrode array size, scalar electrode position, and presence of comorbidity. Conclusion: With LW electrode arrays, HP was achieved in 68% of HEARRRING group patients and 41% of functional classification patients. A ≤ 60 dB HL preimplant pure-tone threshold of 250 Hz was significantly associated with an increased rate of long-term HP.

The Relation of Cochlear Implant Electrode Array Type and Position on Continued Hearing Preservation

“…Preoperative LFPTA and age of implantation were both significant factors for initial and 6-month hearing preservation rates. This is consistent with prior studies (32), although Sweeney et al and O’Connell et al found no correlation between PTA and patient age (12,14). Younger age and lower preoperative LFPTA may be a marker of cochlear and/or neural health.…”

One Year Assessment of the Hearing Preservation Potential of the EVO Electrode Array

“…Despite the different number of tested participants, the distribution of HP scores along the different time points was reasonably equivalent. Although the current sample size is quite limited, these data are mostly aligned with the evidence reported in the literature on comparable electrode lengths and CI procedures [ 25 , 26 , 27 ].…”

“…On a larger sample size, Helbig et al [ 9 ] found that functional low-frequency residual hearing (PTAs low-frequency (125–500 Hz) < 80.0 dB HL) was 85.3% postoperatively, 87.9% after the 12M time point and 95.0% for longer follow-up. Lee et al [ 25 ] assessed HP on 34 ears and found that 41% had functional hearing (no poorer than 85 dB HL at 250 Hz), while 59% did not at one-year post-activation. Looking to the current dataset at 12M, all six participants had better hearing thresholds than 85 dB HL at 250 Hz.…”

One‐Year Hearing Preservation and Speech Outcomes Comparing Slim Modiolar and Lateral Wall Arrays

“…On average, LFPTA shift is approximately 25 dB as reported in the literature at 6 months, 15,23 which lends consideration to updating current HP candidacy criteria to ≤60 dB LFPTA instead of ≤80 or 85 dB. Even with a postoperative LFPTA in the 80 to 85 dB range, acoustic amplification at ≥80 dB becomes more challenging, further limiting the effectiveness of electroacoustic hearing.…”

“…Studies that include severe pure tone thresholds in their inclusion (such as Wanna et al 8 with ≤80 dB for 250 Hz) have expectedly lower HP rates given the little room for functional HP in a patient with 80 dB preop thresholds (they reported 18% HP at 1 year in their series of 225 implants). On average, LFPTA shift is approximately 25 dB as reported in the literature at 6 months, 15,23 which lends consideration to updating current HP candidacy criteria to ≤60 dB LFPTA instead of ≤80 or 85 dB. Even with a postoperative LFPTA in the 80 to 85 dB range, acoustic amplification at ≥80 dB becomes more challenging, further limiting the effectiveness of electroacoustic hearing.…”