Erin C. Schafer

Long-term effects of non-linear frequency compression for children with moderate hearing loss

Abstract Objective: To evaluate non-linear frequency compression (NLFC) as a means to improve speech recognition for children with moderate to moderately-severe hearing loss following a six-month acclimatization period. Design: Within subject design with repeated measures across test conditions. Study Sample: Fifteen children, ages 5 to 13 years, with moderate to moderately-severe high-frequency sensorineural hearing loss were fitted with Phonak Nios, micro-sized, BTE hearing aids and evaluated after two six-week intervals with and without NLFC and again after a six-month period of consecutive NLFC use. Results: Using repeated measures analyses, the six-month results were compared to data that was collected following six-week trials with and without NLFC hearing aids (36). Improvements seen with NLFC in the initial study (36) were maintained or significantly increased in the present study. When compared to the six-week data, aided non-sense syllable speech recognition thresholds in quiet and speech recognition in noise were significantly better at the six-month interval. Conclusions: These results suggest that NLFC improves audibility for and recognition of high-frequency speech sounds for children with moderate to moderately-severe hearing loss. In many cases, improvements found with NLFC increased with a longer period of acclimatization to the technology. Sumario Objetivo: Evaluar la compresión no lineal de la frecuencia (NLFC) como un medio para mejorar el reconocimiento del lenguaje en niños con pérdidas auditivas moderadas a moderadamente severas, luego de un periodo de seis meses de aclimatación. Diseño: Es un diseño intra-sujeto con mediciones repetidas en todas las condiciones de la prueba Muestra del Estudio: Quince niños, edades de 5 a 13 años, con hipoacusia sensorineural moderada a moderadamente severa en altas frecuencias, fueron adaptados con auxiliares auditivos retroauriculares, de micro-tamaño, Phonak Nios, y evaluado luego de dos intervalos de seis semanas, con o sin NLFC y de nuevo, luego de un periodo de seis meses de uso consecutivo de NLFC. Resultados: Usando análisis de medidas repetidas, los resultados a seis meses se compararon con datos que fueron recogidos luego de periodos de seis semanas, con y sin auxiliares auditivos NLFC (Wolfe y col, en prensa). Las mejorías que se ven con NLFC en el estudio inicial (Wolfe y col, en prensa) se mantuvieron o fueron significativamente aumentadas en el presente estudio. Cuando se compararon con los datos de seis semanas, los umbrales no amplificados de reconocimiento del lenguaje para sílabas sin sentido en silencio y de reconocimiento del lenguaje en ruido, fueron significativamente mejores en el intervalo de seis meses. Conclusiones: Estos resultados sugieren que la NLFC mejora la audibilidad y el reconocimiento de sonidos lingüísticos de alta frecuencia para niños con hipoacusias moderadas a moderadamente severas. En muchos casos, la mejoría encontrada con NLFC aumentó con un periodo más largo de aclimatación a la tecnología.

Evaluation of nonlinear frequency compression for school-age children with moderate to moderately severe hearing loss.

BACKGROUND Previous research has indicated that children with moderate hearing loss experience difficulty with recognition of high-frequency speech sounds, such as fricatives and affricates. Conventional behind-the-ear (BTE) amplification typically does not provide ample output in the high frequencies (4000 Hz and beyond) to ensure optimal audibility for these sounds. PURPOSE To evaluate nonlinear frequency compression (NLFC) as a means to improve speech recognition for children with moderate to moderately severe hearing loss. RESEARCH DESIGN Within subject, crossover design with repeated measures across test conditions. STUDY SAMPLE Fifteen children, aged 5-13 yr, with moderate to moderately severe high-frequency sensorineural hearing loss were fitted with Phonak Nios, microsized, BTE hearing aids. These children were previous users of digital hearing aids and communicated via spoken language. Their speech and language abilities were age-appropriate. DATA COLLECTION AND ANALYSIS Aided thresholds and speech recognition in quiet and in noise were assessed after 6 wk of use with NLFC and 6 wk of use without NLFC. Participants were randomly assigned to counter-balanced groups so that eight participants began the first 6 wk trial with NLFC enabled and the other seven participants started with NLFC disabled. Then, the provision of NLFC was switched for the second 6 wk trial. Speech recognition in quiet was assessed via word recognition assessments with the University of Western Ontario (UWO) Plural Test and recognition of vowel-consonant-vowel nonsense syllables with the Phonak Logatome test. Speech recognition in noise was assessed by evaluating the signal-to-noise ratio in dB for 50% correct performance on the Bamford-Kowal-Bench Speech-in-Noise (BKB-SIN) test, an adaptive test of speech perception in a multitalker babble background. RESULTS Aided thresholds for high-frequency stimuli were significantly better when NLFC was enabled, and use of NLFC resulted in significantly better speech recognition in quiet for the UWO Plural Test and for the phonemes /d/ and /s/ on the Phonak Logatome test. There was not a statistically significant difference in performance on the BKB-SIN test between the NLFC enabled and disabled conditions. CONCLUSIONS These results indicate that NLFC improves audibility for and recognition of high-frequency speech sounds for children with moderate to moderately severe hearing loss in quiet listening situations.

A meta-analysis to compare speech recognition in noise with bilateral cochlear implants and bimodal stimulation

Abstract Objective: This investigation quantified the relative benefits of binaural CI arrangements (i.e., bilateral, bimodal) for three binaural phenomena (i.e., binaural squelch, binaural summation, head-shadow effect) and sensitivity of two speech-recognition test paradigms (i.e., adaptive and fixed). Design: A repeated-measures meta-analytical approach was used to compare effect sizes between binaural CI arrangements for each of the three binaural-listening phenomena and between the two test paradigms. Study sample: A total of 95 effect sizes were calculated and analyzed from 42 peer-reviewed studies published between January 2000 and April 2011. Results: Findings revealed significant effect sizes for both CI arrangements for the binaural phenomena of summation and head-shadow effect. A significant effect size for binaural squelch was determined only for bilateral CI users. Further, the two paradigms resulted in similar effect sizes for bilateral and bimodal users, with the exception of binaural squelch. Here, significant effect sizes were significant only in the fixed-testing paradigm. Conclusions: The average user of binaural CI arrangements realizes the binaural phenomena of summation and the head-shadow effect, but only the bilateral CI arrangement is afforded the advantage of binaural squelch. Statistically, listeners fit with bilateral CIs have a slight advantage in binaural performance over those using bimodal stimulation. Sumario Objetivo: Esta investigación cuantifica los beneficios relativos de las adaptaciones binaurales de IC (p.e., bilaterales, bimodales) en cuanto a tres fenómenos binaurales (p.e., chapoteo binaural, sumación binaural, efecto de sombra de la cabeza) y la sensibilidad de dos paradigmas de prueba para el reconocimiento del lenguaje. Diseño: Se utilizó un enfoque meta-analítico de medidas repetidas para comparar el grado del efecto en las adaptaciones binaurales de CI para cada uno de los tres fenómenos de audición binaural y entre los dos paradigmas de prueba. Muestra Del Estudio: Se calculó y se analizó un total de 95 efectos en 42 estudios con revisión editorial, publicados entre enero del 2000 y abril del 2011. Resultados: Los hallazgos revelaron grados significativos de efecto para ambas adaptaciones de CI, tanto para el fenómeno de sumación como para el de efectos sombra de la cabeza. Se determinó un grado significativo de efecto para el chapoteo binaural sólo para los usuarios de CI bilaterales. Más aún, los dos paradigmas rindieron resultados de grado similar para usuarios bilaterales y bimodales, con la excepción del chapoteo binaural. Aquí, los grados de efecto fueron significativos solamente para el paradigma de prueba fija. Conclusiones: El usuario promedio con adaptación binaurales de CI se da cuenta del fenómeno binaural de sumación y el efecto de sombra de la cabeza, pero solo al arreglo de CI bilateral le da la ventaja del chapoteo binaural. Estadísticamente, los sujetos adaptados con CI bilaterales tienen una ligera ventaja en el desempeño binaural sobre aquellos que utilizan estimulación bimodal.

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.

Personal FM systems for children with autism spectrum disorders (ASD) and/or attention-deficit hyperactivity disorder (ADHD): An initial investigation

UNLABELLED The goal of this initial investigation was to examine the potential benefit of a frequency modulation (FM) system for 11 children diagnosed with autism spectrum disorders (ASD), attention-deficit hyperactivity disorder (ADHD), or both disorders through measures of speech recognition performance in noise, observed classroom behavior, and teacher-rated educational risk and listening behaviors. Use of the FM system resulted in significant average improvements in speech recognition in noise for the children with ASD and ADHD as well as large effect sizes. When compared to typically functioning peers, children with ASD and ADHD had significantly poorer average speech recognition performance in noise without the FM system but comparable average performance when the FM system was used. Similarly, classroom observations yielded a significant increase in on-task behaviors and large effect sizes when the FM system was in use during two separate trial periods. Although teacher ratings on questionnaires showed no significant improvement in the average level of educational risk of participants, they did indicate significant improvement in average listening behaviors during two trial periods with the FM system. Given the significantly better speech recognition in noise, increased on-task behaviors, and improved teacher ratings of listening behaviors with the FM system, these devices may be a viable option for children who have ASD and ADHD in the classroom. However, an individual evaluation including audiological testing and a functional evaluation in the childs primary learning environment will be necessary to determine the benefit of an FM system for a particular student. LEARNING OUTCOMES 1. The reader will be able to describe the potential benefit of FM systems for children with ASD and/or ADHD. 2. The reader will be able to identify on-task versus off-task listening behaviors in children with ASD and/or ADHD. 3. The reader will be able to explain the components of a successful pre-fit education program that may be necessary prior to fitting an FM system in children with ASD.

Developmental effects and spatial hearing in young children with normal-hearing sensitivity.

Objectives: Previous research suggests that young children have significant difficulty recognizing speech in the presence of background noise as compared with older children and adults. However, limited research exists that examines the developmental effects of speech recognition in noise in separate age groups of young children, especially in a classroom setting. The lack of research may relate to the limited number of tests with multiple, equally intelligible lists in noise that are also appropriate for young children. As a result, the goals of the present study include investigating (1) effects of age and (2) benefits of spatial separation of speech and noise sources on the speech recognition in noise performance of young children with normal-hearing sensitivity. A secondary goal of the study was to establish the validity and reliability of the Phrases in Noise Test (PINT) for assessing the 50% correct speech-in-noise threshold of young children. Design: The investigators used a two-way repeated measures design to examine the main effects of age and spatial separation. Sixty-eight children in separate groups of 3-, 4-, 5-, and 6-year-olds and 17 adults completed two speech-recognition conditions with (1) speech and noise from the same loudspeaker at 0-degree azimuth (S0/N0) and (2) speech and noise from separate loudspeakers at 0- and 180-degree azimuth (S0/N180). Recruiting sites included local preschools and school districts for children and a university for adults. Results: The results of this investigation suggest that younger children (<4 years of age) have significantly poorer speech-in-noise thresholds than older children and adults, and 4- and 5-year-old children also have significantly poorer performance than adults when speech and noise are presented from the same spatial location. All participants obtained significant spatial release from masking. On a parent and teacher screening questionnaire to assess educational risk, five of 12 children with at-risk behaviors had poor speech-in-noise thresholds relative to their peers. When two lists of the PINT are used, the test seems to be a valid and reliable measure for assessing young children’s speech-in-noise thresholds. Conclusions: Young children exhibit significantly poorer speech recognition than do older children and adults in a classroom, especially when speech and noise are presented from the same location. Given the poor acoustics of typical classrooms, and the earlier age at which many children are educated, special modifications to classrooms may be necessary to improve listening through acoustic modifications or classroom amplification. A combination of a parent or teacher questionnaire and the PINT may be helpful in identifying children who are at risk for educational delays and listening difficulties in classrooms with typically poor acoustics.

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.

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.

Effects of input processing and type of personal frequency modulation system on speech-recognition performance of adults with cochlear implants

Objectives: The objective of this study was to compare speech recognition in quiet and in noise for cochlear implant recipients using two different types of personal frequency modulation (FM) systems (directly coupled [direct auditory input] versus induction neckloop) with each of two sound processors (Cochlear Nucleus Freedom versus Cochlear Nucleus 5). Two different experiments were conducted within this study. In both these experiments, mixing of the FM signal within the Freedom processor was implemented via the same scheme used clinically for the Freedom sound processor. In Experiment 1, the aforementioned comparisons were conducted with the Nucleus 5 programmed so that the microphone and FM signals were mixed and then the mixed signals were subjected to autosensitivity control (ASC). In Experiment 2, comparisons between the two FM systems and processors were conducted again with the Nucleus 5 programmed to provide a more complex multistage implementation of ASC during the preprocessing stage. Design: This study was a within-subject, repeated-measures design. Subjects were recruited from the patient population at the Hearts for Hearing Foundation in Oklahoma City, OK. Fifteen subjects participated in Experiment 1, and 16 subjects participated in Experiment 2. Subjects were adults who had used either unilateral or bilateral cochlear implants for at least 1 year. Results: In this experiment, no differences were found in speech recognition in quiet obtained with the two different FM systems or the various sound-processor conditions. With each sound processor, speech recognition in noise was better with the directly coupled direct auditory input system relative to the neckloop system. The multistage ASC processing of the Nucleus 5 sound processor provided better performance than the single-stage approach for the Nucleus 5 and the Nucleus Freedom sound processor. Conclusions: Speech recognition in noise is substantially affected by the type of sound processor, FM system, and implementation of ASC used by a Cochlear implant recipient.