Voice gender and the segregation of competing talkers: Perceptual learning in cochlear implant simulations.

Two experiments explored the role of differences in voice gender in the recognition of speech masked by a competing talker in cochlear implant simulations. Experiment 1 confirmed that listeners with normal hearing receive little benefit from differences in voice gender between a target and masker sentence in four- and eight-channel simulations, consistent with previous findings that cochlear implants deliver an impoverished representation of the cues for voice gender. However, gender differences led to small but significant improvements in word recognition with 16 and 32 channels. Experiment 2 assessed the benefits of perceptual training on the use of voice gender cues in an eight-channel simulation. Listeners were assigned to one of four groups: (1) word recognition training with target and masker differing in gender; (2) word recognition training with same-gender target and masker; (3) gender recognition training; or (4) control with no training. Significant improvements in word recognition were observed from pre- to post-test sessions for all three training groups compared to the control group. These improvements were maintained at the late session (one week following the last training session) for all three groups. There was an overall improvement in masked word recognition performance provided by gender mismatch following training, but the amount of benefit did not differ as a function of the type of training. The training effects observed here are consistent with a form of rapid perceptual learning that contributes to the segregation of competing voices but does not specifically enhance the benefits provided by voice gender cues.

Assistive technology evaluations: Remote-microphone technology for children with Autism Spectrum Disorder.

The goal of this study was to conduct assistive technology evaluations on 12 children diagnosed with Autism Spectrum Disorder (ASD) to evaluate the potential benefits of remote-microphone (RM) technology. A single group, within-subjects design was utilized to explore individual and group data from functional questionnaires and behavioral test measures administered, designed to assess school- and home-based listening abilities, once with and once without RM technology. Because some of the children were unable to complete the behavioral test measures, particular focus was given to the functional questionnaires completed by primary teachers, participants, and parents. Behavioral test measures with and without the RM technology included speech recognition in noise, auditory comprehension, and acceptable noise levels. The individual and group teacher (n=8-9), parent (n=8-9), and participant (n=9) questionnaire ratings revealed substantially less listening difficulty when RM technology was used compared to the no-device ratings. On the behavioral measures, individual data revealed varied findings, which will be discussed in detail in the results section. However, on average, the use of the RM technology resulted in improvements in speech recognition in noise (4.6dB improvement) in eight children, higher auditory working memory and comprehension scores (12-13 point improvement) in seven children, and acceptance of poorer signal-to-noise ratios (8.6dB improvement) in five children. The individual and group data from this study suggest that RM technology may improve auditory function in children with ASD in the classroom, at home, and in social situations. However, variability in the data and the inability of some children to complete the behavioral measures indicates that individualized assistive technology evaluations including functional questionnaires will be necessary to determine if the RM technology will be of benefit to a particular child who has ASD.

Electromagnetic versus electrical coupling of personal frequency modulation (FM) receivers to cochlear implant sound processors.

BACKGROUND: Previous research has suggested that electrically coupled frequency modulation (FM) systems substantially improved speech-recognition performance in noise in individuals with cochlear implants (CIs). However, there is limited evidence to support the use of electromagnetically coupled (neck loop) FM receivers with contemporary CI sound processors containing telecoils. PURPOSE: The primary goal of this study was to compare speech-recognition performance in noise and subjective ratings of adolescents and adults using one of three contemporary CI sound processors coupled to electromagnetically and electrically coupled FM receivers from Oticon. RESEARCH DESIGN: A repeated-measures design was used to compare speech-recognition performance in noise and subjective ratings without and with the FM systems across three test sessions (Experiment 1) and to compare performance at different FM-gain settings (Experiment 2). Descriptive statistics were used in Experiment 3 to describe output differences measured through a CI sound processor. STUDY SAMPLE: Experiment 1 included nine adolescents or adults with unilateral or bilateral Advanced Bionics Harmony (n = 3), Cochlear Nucleus 5 (n = 3), and MED-EL OPUS 2 (n = 3) CI sound processors. In Experiment 2, seven of the original nine participants were tested. In Experiment 3, electroacoustic output was measured from a Nucleus 5 sound processor when coupled to the electromagnetically coupled Oticon Arc neck loop and electrically coupled Oticon R2. DATA COLLECTION AND ANALYSIS: In Experiment 1, participants completed a field trial with each FM receiver and three test sessions that included speech-recognition performance in noise and a subjective rating scale. In Experiment 2, participants were tested in three receiver-gain conditions. Results in both experiments were analyzed using repeated-measures analysis of variance. Experiment 3 involved electroacoustic-test measures to determine the monitor-earphone output of the CI alone and CI coupled to the two FM receivers. RESULTS: The results in Experiment 1 suggested that both FM receivers provided significantly better speech-recognition performance in noise than the CI alone; however, the electromagnetically coupled receiver provided significantly better speech-recognition performance in noise and better ratings in some situations than the electrically coupled receiver when set to the same gain. In Experiment 2, the primary analysis suggested significantly better speech-recognition performance in noise for the neck-loop versus electrically coupled receiver, but a second analysis, using the best performance across gain settings for each device, revealed no significant differences between the two FM receivers. Experiment 3 revealed monitor-earphone output differences in the Nucleus 5 sound processor for the two FM receivers when set to the +8 setting used in Experiment 1 but equal output when the electrically coupled device was set to a +16 gain setting and the electromagnetically coupled device was set to the +8 gain setting. CONCLUSIONS: Individuals with contemporary sound processors may show more favorable speech-recognition performance in noise electromagnetically coupled FM systems (i.e., Oticon Arc), which is most likely related to the input processing and signal processing pathway within the CI sound processor for direct input versus telecoil input. Further research is warranted to replicate these findings with a larger sample size and to develop and validate a more objective approach to fitting FM systems to CI sound processors.

Benefit of a commercially available cochlear implant processor with dual-microphone beamforming: a multi-center study.

OBJECTIVE: Previous research shows that cochlear implant users experience significant difficulty with speech perception in noisy listening situations. There is a paucity of research evaluating the potential improvement in speech recognition in noise provided by a dual-microphone directional system in a commercial implant sound processor. The primary objective of this study was to compare speech recognition in quiet and in noise for the Nucleus Freedom and Nucleus 5 CP810 sound processors set to the manufacturer's default user programs for quiet and noisy environments. RESEARCH DESIGN: Crossover with repeated-measures design. SETTING: This multi-center study was conducted across four cochlear implant clinics in the United States. PATIENTS: Thirty-five adults with unilateral Nucleus Freedom cochlear implants. All subjects had used their cochlear implant for at least 6 months and had substantial open-set word recognition as evidenced by a score of at least 40% correct on the Consonant-Nucleus-Consonant (CNC) monosyllabic word recognition test in quiet. INTERVENTION: All subjects (previous users of the Nucleus Freedom sound processor) were fitted with the Nucleus 5 sound processor. Performance was assessed while these subjects used each sound processor in the default user program the manufacturer recommends for quiet and noisy conditions. MAIN OUTCOME MEASURES: Speech recognition was assessed with CNC monosyllabic words in quiet and sentences in noise from the BKB-SIN (Bamford-Kowal-Bench Sentences in Noise) test. The data were analyzed with descriptive statistics and performance with each processor in each listening condition was compared using a repeated-measures analysis of variance. RESULTS: Word recognition in quiet was significantly better with the Nucleus 5 sound processor when compared to performance with the Nucleus Freedom processor. In noise, the Nucleus 5 sound processor also provided a significant improvement in speech recognition relative to the performance with the Nucleus Freedom. CONCLUSION: The results of the study suggest that the Nucleus 5 sound processor provides significantly better speech recognition in quiet and in noise when compared with performance with the Nucleus Freedom processor.

The effect of front-end processing on cochlear implant performance of children.

OBJECTIVE: Previous research shows that children using cochlear implants experience significant difficulty with speech perception in noisy listening situations. There are several types of input signal processing available for the cochlear implant sound processor; however, there is a paucity of research to support this technology for children. The primary objective of this study was to examine the potential benefits of 2 types of input signal processing, adaptive dynamic range optimization (ADRO) as compared with autosensitivity (ASC) plus ADRO for children using Cochlear Corporation implants. RESEARCH DESIGN: Cross-sectional repeated-measures design. SETTING: Outpatient nonprofit foundation providing audiology services and auditory-verbal therapy. PATIENTS: Eleven children, aged 4 years 4 months to 12 years, with unilateral or bilateral Cochlear Limited implants. All children used their cochlear implant(s) for at least 1 year, had no additional disabilities, were enrolled in preschool or elementary school, and had age-appropriate receptive and expressive language. INTERVENTION: All children used Cochlear Limited cochlear implants with either the Nucleus Freedom or Nucleus 5 cochlear implant sound processor. Performance was assessed while these children used ADRO-only input processing and ASC+ADRO input processing. MAIN OUTCOME MEASURES: Speech perception of PBK-50 monosyllabic words in quiet and BKB-SIN sentences in noise was measured for each child. In the noise conditions, children were using the ADRO-only or ASC+ADRO input signal processing strategies. The data in quiet were analyzed with descriptive statistics, and the conditions in noise were compared using a 1-way repeated-measures analysis of variance. RESULTS: All children demonstrated word recognition in quiet at or above 90% correct. In noise, sentence-perception performance in the ASC+ADRO condition was significantly better than that in the ADRO-alone condition. CONCLUSION: The results of the study suggest substantial benefit from combining 2 types of input signal processing, ASC and ADRO, for children with unilateral and bilateral cochlear implants. Specifically, signal processing to adjust the sensitivity of the sound processor microphone automatically has substantial positive effects on speech-perception thresholds in noise.

Effects of FM-receiver gain on speech-recognition performance of adults with cochlear implants.

The primary aim of this study was to examine the effects of frequency-modulated (FM) settings on speech-recognition performance in noise of listeners using two different cochlear implant speech processors. Participants included eight users of ESPrit 3G speech processors and nine users of Auria speech processors. A modified adaptive-testing paradigm was used to assess speech recognition in noise with the cochlear implant and FM system at four receiver-gain settings: +6, +10, +14, or +20. In the no-FM condition, performance differences were not detected between the two processor groups. In the FM conditions, significantly better performance was found for participants with the Auria processor compared to those using the ESPrit 3G processor. Increases in receiver gain did not significantly improve speech recognition of participants using ESPrit 3G processors, but did significantly influence performance for those using Auria processors. For Auria users, the +6 setting resulted in significantly poorer performance than all other conditions, and optimal FM performance was found in the +14 and +20 gain settings. Clinical recommendations will be provided according to results of the study.