RP307 - Retroactive Fitting of EAS Processors Following Full-Length Cochlear Implant Insertion

Abstract:
This study was conducted to determine if patients with residual hearing following insertion of a full length electrode array would benefit from having an EAS system activated. Testing of CNC and AzBio scores in quiet and noise was completed after at least 3 months of use in 3 conditions: Electric only, EAS-A (full electric with acoustic overlap) and EAS-B (no overlap between electric and acoustic). Preliminary results demonstrate statistically significant improvement in CNC scores with EAS-A compared to electric only mapping. Analysis of subjective questionnaires is ongoing.

Summary:
Rationale/Purpose
Electric Acoustic Stimulation (EAS) Systems have become an important technological advancement for patients who undergo cochlear implantation. With advancements in cochlear implant technology and surgical technique, preserving residual hearing after cochlear implantation is becoming more common allowing patients to hear with both electric and acoustic signals.

There is a significant portion of patients who have undergone cochlear implantation with a full length electrode (Flex28) that have residual hearing after surgery (≤65 dB HL at 125, 250, 500, 1000, or 1500 Hz) that could accommodate activation of an acoustic channel. This study was conducted to determine if patients with residual hearing following insertion of a full length electrode array would benefit from having an EAS system activated.

Methods
Subjects were recruited from Pittsburgh Ear Associates and could be enrolled in if between 18-95 years old, native English speakers, with either unilateral or bilateral cochlear implants. Subjects were implanted with the Med El Synchrony or Synchrony 2 implant and Flex28 electrode, had residual hearing at at least one frequency, and had worn their implant for at least 3 months with full electric programming.

Subjects were fit with the Sonnet 2 EAS processor and programmed with two different strategies: a full electric with acoustic overlap program (EAS-A) and the Maestro default with no overlap between acoustic and electric stimulation (EAS-B). After 3 months of wearing each strategy subjects were tested for thresholds, CNC, AzBio in quiet and AzBio in noise. Preliminary analysis of the end-point data for 11 ears were analyzed. Paired T-tests were used to compare the results.

Results
A total of 15 subjects and 16 ears (1 bilateral subject) were enrolled in the study as of January 2022. Data from 11 ears completed the study, 3 subjects dropped out and 1 is still enrolled in the study. Participants scored on average 65.5%, 78.8% and 59.6% in CNC, Azbio Quiet and AzBio Noise respectively when using electric only stimulation. They scored 71.6%, 78.6% and 58.2% when using EAS-A and 67.6%, 77.8% and 61.7% when they used EAS-B. Statistical analysis showed that participants performed significantly better (p < 0.05) on CNC word with EAS-A (71.6%) vs. Electric (65.5%). All other performance differences were not statistically significant.

Ultimately, 3 participants chose to keep the electric only system due to lack of perceived benefit and discomfort from wearing an earmold. Of those choosing to keep EAS, 5 chose EAS-A and 3 chose EAS-B.

Conclusion
Preliminary results suggest possible benefit of retroactively fitting patients with residual hearing after cochlear implantation with an EAS system. Initial subgroup analysis suggests that EAS-A performed better than electric or EAS-B on CNC words. We found that personal preference and the choice of whether or not to wear an earmold mattered more than the scores on testing. Analysis of subjective questionnaires is ongoing.