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.

Evaluation of a wireless audio streaming accessory to improve mobile telephone performance of cochlear implant users.

OBJECTIVE: The objective of this study was to evaluate the potential improvement in word recognition in quiet and in noise obtained with use of a Bluetooth-compatible wireless hearing assistance technology (HAT) relative to the acoustic mobile telephone condition (e.g. the mobile telephone receiver held to the microphone of the sound processor). DESIGN: A two-way repeated measures design was used to evaluate differences in telephone word recognition obtained in quiet and in competing noise in the acoustic mobile telephone condition compared to performance obtained with use of the CI sound processor and a telephone HAT. STUDY SAMPLE: Sixteen adult users of Nucleus cochlear implants and the Nucleus 6 sound processor were included in this study. RESULTS: Word recognition over the mobile telephone in quiet and in noise was significantly better with use of the wireless HAT compared to performance in the acoustic mobile telephone condition. Word recognition over the mobile telephone was better in quiet when compared to performance in noise. CONCLUSIONS: The results of this study indicate that use of a wireless HAT improves word recognition over the mobile telephone in quiet and in noise relative to performance in the acoustic mobile telephone condition for a group of adult cochlear implant recipients.

Benefits of Adaptive Signal Processing in a Commercially Available Cochlear Implant Sound Processor.

OBJECTIVE: Cochlear implant recipients often experience difficulty understanding speech in noise. The primary objective of this study was to evaluate the potential improvement in speech recognition in noise provided by an adaptive, commercially available sound processor that performs acoustic scene classification and automatically adjusts input signal processing to maximize performance in noise. RESEARCH DESIGN: Within-subjects, repeated-measures design. SETTING: This multicenter study was conducted across five sites in the U.S.A. and Australia. PATIENTS: Ninety-three adults and children with Nucleus Freedom, CI422, and CI512 cochlear implants. INTERVENTION: Subjects (previous users of the Nucleus 5 sound processor) were fitted with the Nucleus 6 sound processor. Performance was assessed while these subjects used each sound processor in the manufacturer's recommended default program (standard directionality, ASC + ADRO for the Nucleus 5 processor and ASC + ADRO and SNR-NR with SCAN for the Nucleus 6 sound processor). The subjects were also evaluated with the Nucleus 6 with standard directionality, ASC + ADRO and SNR-NR enabled but SCAN disabled. MAIN OUTCOME MEASURES: Speech recognition in noise was assessed with AzBio sentences. RESULTS: Sentence recognition in noise was significantly better with the Nucleus 6 sound processor when used with the default input processing (ASC + ADRO, SNR-NR, and SCAN) compared to performance with the Nucleus 5 sound processor and default input processing (standard directionality, ASC + ADRO). Specifically, use of the Nucleus 6 at default settings resulted in a mean improvement in sentence recognition in noise of 27 percentage points relative to performance with the Nucleus 5 sound processor. Use of the Nucleus 6 sound processor using standard directionality, ASC + ADRO and SNR-NR (SCAN disabled) resulted in a mean improvement of 9 percentage points in sentence recognition in noise compared to performance with the Nucleus 5. CONCLUSION: The results of this study suggest that the Nucleus 6 sound processor with acoustic scene classification, automatic, adaptive directionality, and speech enhancement in noise processing provides significantly better speech recognition in noise when compared to performance with the Nucleus 5 processor.

Nucleus Freedom North American clinical trial.

OBJECTIVE: To evaluate hearing outcomes and effects of stimulation rate on performance with the Nucleus Freedom cochlear implant (Cochlear Americas, Denver, CO). STUDY DESIGN AND SETTING: Randomized, controlled, prospective, single-blind clinical study using single-subject repeated measures (A-B-A-B) design at 14 academic centers in the United States and Canada and comparison with outcomes of a prior device by the same manufacturer. PATIENTS: Seventy-one severely/profoundly hearing impaired adults. RESULTS: Seventy-one adult recipients were randomly programmed in two different sets of rate: ACE or higher rate ACE RE. Mean scores for Consonant Nucleus Consonant words is 57%, Hearing in Noise Test (HINT) sentences in quiet 78%, and HINT sentences in noise 64%. Sixty-seven percent of subjects preferred slower rates of stimulation, and performance did not improve with higher rates of stimulation using this device. CONCLUSIONS: Subjects performed well, and there was no advantage to higher stimulation rates with this device. SIGNIFICANCE: Higher stimulation rates do not necessarily result in improved performance.