Multicenter US Clinical Trial With an Electric-Acoustic Stimulation (EAS) System in Adults: Final Outcomes

Abstract

Objective: To demonstrate the safety and effectiveness of the MED-EL Electric-Acoustic Stimulation (EAS) System, for adults with residual low-frequency hearing and severe-to-profound hearing loss in the mid to high frequencies.

Study design: Prospective, repeated measures.

Setting: Multicenter, hospital.

Patients: Seventy-three subjects implanted with PULSAR or SONATA cochlear implants with FLEX electrode arrays.

Intervention: Subjects were fit postoperatively with an audio processor, combining electric stimulation and acoustic amplification.

Main outcome measures: Unaided thresholds were measured preoperatively and at 3, 6, and 12 months postactivation. Speech perception was assessed at these intervals using City University of New York sentences in noise and consonant-nucleus-consonant words in quiet. Subjective benefit was assessed at these intervals via the Abbreviated Profile of Hearing Aid Benefit and Hearing Device Satisfaction Scale questionnaires.

Results: Sixty-seven of 73 subjects (92%) completed outcome measures for all study intervals. Of those 67 subjects, 79% experienced less than a 30 dB HL low-frequency pure-tone average (250-1000 Hz) shift, and 97% were able to use the acoustic unit at 12 months postactivation. In the EAS condition, 94% of subjects performed similarly to or better than their preoperative performance on City University of New York sentences in noise at 12 months postactivation, with 85% demonstrating improvement. Ninety-seven percent of subjects performed similarly or better on consonant-nucleus-consonant words in quiet, with 84% demonstrating improvement.

Conclusion: The MED-EL EAS System is a safe and effective treatment option for adults with normal hearing to moderate sensorineural hearing loss in the low frequencies and severe-to-profound sensorineural hearing loss in the high frequencies who do not benefit from traditional amplification.

Conflict of interest statement

The authors disclose no conflicts of interest.

Figures

FIG. 1

Average pure-tone unaided thresholds. Lines show mean audiograms obtained preoperatively (gray, solid line, diamonds), at 3 months (gray, long-dash line, circles), at 6 months (gray, short-dash line, stars) and at 12 months postactivation (black line, triangles). Error bars indicating standard deviation from the mean are shown for the preop and 12 month intervals.

FIG. 2

Speech recognition scores for all subjects followed through the 12-month postactivation interval. Scores for CUNY sentences in noise (A) and CNC words in quiet (B) are represented by filled circles for subjects using EAS and open triangles for subjects tested in the CI-alone condition. A solid reference line is shown on both figures, indicating no change in score from the preoperative to the 12 month postactivation interval. Dashed lines are shown at ± 10% of the solid reference line to indicate scores that may fall within test-retest variability. CI indicates cochlear implant; CNC, consonant-nucleus-consonant; CUNY, City University of New York; EAS, electric-acoustic stimulation.

FIG. 3

Speech recognition scores for the profound hearing loss group. Individual subject scores for CUNY sentences in noise (A) and CNC words in quiet (B) are represented by the same symbol in both the figures. Filled symbols indicate subjects with best performance using EAS and open symbols indicate subjects with best performance using CI-alone. A solid reference line is shown on both the figures, indicating no change in score from the preoperative to the 12 month postactivation interval. Dashed lines are shown at ± 10% of the solid reference line to indicate scores that may fall within test–retest variability. CI indicates cochlear implant; CNC, consonant-nucleus-consonant; CUNY, City University of New York; EAS, electric-acoustic stimulation.