Combined Electric and Acoustic Stimulation With Hearing Preservation: Effect of Cochlear Implant Low-Frequency Cutoff on Speech Understanding and Perceived Listening Difficulty.

OBJECTIVE: The primary objective of this study was to assess the effect of electric and acoustic overlap for speech understanding in typical listening conditions using semidiffuse noise. DESIGN: This study used a within-subjects, repeated measures design including 11 experienced adult implant recipients (13 ears) with functional residual hearing in the implanted and nonimplanted ear. The aided acoustic bandwidth was fixed and the low-frequency cutoff for the cochlear implant (CI) was varied systematically. Assessments were completed in the R-SPACE sound-simulation system which includes a semidiffuse restaurant noise originating from eight loudspeakers placed circumferentially about the subject's head. AzBio sentences were presented at 67 dBA with signal to noise ratio varying between +10 and 0 dB determined individually to yield approximately 50 to 60% correct for the CI-alone condition with full CI bandwidth. Listening conditions for all subjects included CI alone, bimodal (CI + contralateral hearing aid), and bilateral-aided electric and acoustic stimulation (EAS; CI + bilateral hearing aid). Low-frequency cutoffs both below and above the original "clinical software recommendation" frequency were tested for all patients, in all conditions. Subjects estimated listening difficulty for all conditions using listener ratings based on a visual analog scale. RESULTS: Three primary findings were that (1) there was statistically significant benefit of preserved acoustic hearing in the implanted ear for most overlap conditions, (2) the default clinical software recommendation rarely yielded the highest level of speech recognition (1 of 13 ears), and (3) greater EAS overlap than that provided by the clinical recommendation yielded significant improvements in speech understanding. CONCLUSIONS: For standard-electrode CI recipients with preserved hearing, spectral overlap of acoustic and electric stimuli yielded significantly better speech understanding and less listening effort in a laboratory-based, restaurant-noise simulation. In conclusion, EAS patients may derive more benefit from greater acoustic and electric overlap than given in current software fitting recommendations, which are based solely on audiometric threshold. These data have larger scientific implications, as previous studies may not have assessed outcomes with optimized EAS parameters, thereby underestimating the benefit afforded by hearing preservation.

Upgrade to Nucleus® 6 in Previous Generation Cochlear™ Sound Processor Recipients.

BACKGROUND: The Nucleus® 6 sound processor is now compatible with the Nucleus® 22 (CI22M)-Cochlear's first generation cochlear implant. The Nucleus 6 offers three new signal processing algorithms that purportedly facilitate improved hearing in background noise. PURPOSE: These studies were designed to evaluate listening performance and user satisfaction with the Nucleus 6 sound processor. RESEARCH DESIGN: The research design was a prospective, single-participant, repeated measures design. STUDY SAMPLE: A group of 80 participants implanted with various Nucleus internal implant devices (CI22M, CI24M, Freedom® CI24RE, CI422, and CI512) were recruited from a total of six North American sites. DATA COLLECTION AND ANALYSIS: Participants had their external sound processor upgraded to the Nucleus 6 sound processor. Final speech perception testing in noise and subjective questionnaires were completed after four or 12 weeks of take-home use with the Nucleus 6. RESULTS: Speech perception testing in noise showed significant improvement and participants reported increased satisfaction with the Nucleus 6. CONCLUSION: These studies demonstrated the benefit of the new algorithms in the Nucleus 6 over previous generations of sound processors.

Clinical Outcomes of the Cochlear™ Nucleus(®) 5 Cochlear Implant System and SmartSound™ 2 Signal Processing.

BACKGROUND: While published data exist regarding cochlear implant (CI) outcomes from large academic programs, evidence of benefit based on national, multicenter clinical trials is needed for information regarding typical patient outcomes of devices implanted by U.S. centers representing larger academic to smaller hospital-based programs. PURPOSE: This nationwide trial evaluated outcomes in a group of newly implanted adult recipients of the Cochlear™ Nucleus(®) 5 CI system and SmartSound™ 2 signal processing. Unlike previous clinical trials, the AzBio sentence test was used and represents recent transition in our field to use of more challenging test materials. It was hypothesized that (1) speech perception scores in quiet with SmartSound™ 2 signal processing would not be statistically different from previous-generation devices; (2) speech perception scores in noise with SmartSound™ 2 signal processing would be better with enhanced microphone directionality; (3) speech perception scores in noise will be better with the preferred SmartSound™ 2 program for listening in noise; and (4) cochlear implantation would improve quality of life as assessed by the updated Health Utility Index Mark 3 (HUI3). A secondary purpose was to examine the relationships among the current and previously used speech perception tests of the Minimum Speech Test Battery (MSTB). It was hypothesized that speech perception scores within the same test interval would show predictive relationships. RESEARCH DESIGN: Prospective, single-arm, repeated-measures study across 13 CI centers in the United States between February 2010 and June 2012. The participating centers ranged from larger academic to smaller hospital-based programs to accurately represent the diversity of programs in the United States. STUDY SAMPLE: Participants were 38 postlingually deafened adult CI candidates. DATA COLLECTION AND ANALYSIS: Primary measures were Consonant-Nucleus-Consonant (CNC) words in quiet and the AzBio Sentence Test in Quiet (AzBioQ) and in Noise (AzBioN) tested at preoperative, and 3-, 6-, and 12-mo postactivation intervals. Quality of life was measured with the HUI3. For the secondary objective, statistical analyses were performed to investigate the predictive properties between current and previously used MSTB tests. RESULTS: Mean CNC scores were significantly higher compared to the Nucleus(®) 24 Contour™ at 3 mo (p < 0.05) postactivation and showed no difference compared to the Nucleus(®) Freedom™ at 6 mo postactivation. Both SmartSound™ 2 FOCUS and NOISE programs provided significant improvements in performance in noise over the EVERYDAY program (p < 0.001), and performance with the FOCUS program was significantly better compared to the NOISE program (p < 0.001). Speech perception in noise was not related to patients' subjective program preferences. Quality-of-life outcomes showed significant improvements from the preoperative to 6-mo postactivation interval (p < 0.05-0.001). Strong and significant correlations were found between preoperative CNC and AzBioQ and preoperative Hearing-in-Noise Test sentences in Quiet (HINTQ) and AzBioQ. At 12-mo postactivation, there were strong and highly significant correlations between CNC and AzBioQ, HINTQ and AzBioQ, and Hearing-in-Noise Test sentences in Noise and AzBioN (all p < 0.001). CONCLUSIONS: Results of this national clinical trial showed significant improvements in speech perception and quality of life following cochlear implantation. SmartSound™ 2 signal processing features showed a significant benefit of FOCUS when listening in noise, although preference of signal processing feature did not correlate with performance. Significant correlations were observed between speech perception tests. The findings of this study can be applied in clinical assessment, programming, and follow-up for CI candidates and recipients.

The history of Cochlear™ Nucleus® sound processor upgrades: 30 years and counting.

To review developments in sound processors over the past 30 years that have resulted in significant improvements in outcomes for Nucleus® recipients.