Effects of Frequency Compression Hearing Aids for Unilaterally Implanted Children With Acoustically Amplified Residual Hearing in the Nonimplanted Ear
ABSTRACT The primary objective of this study is to evaluate the benefits of nonlinear frequency compression (NLFC) hearing aids in the nonimplanted ears of children with unilateral cochlear implants (CIs). It is hypothesized that speech perception performance will benefit from complementary auditory cues provided by the CI and the hearing aid, particularly with the increased access to high-frequency sounds provided by NLFC.
Eleven children using unilateral CIs with usable residual hearing in the nonimplanted ears were enrolled in the study and fitted with NLFC hearing aids. The test protocol included consonant-nucleus-consonant words in quiet, the Hearing in Noise Test sentences presented in speech noise and two-talker maskers, and a consonant identification task. Subjects were tested in a CI-alone condition as well as bimodally, with and without NLFC enabled.
The results support previous work in adults and children, demonstrating the beneficial effects of bimodal listening. Frequency compression did not significantly affect performance for the children enrolled in this study, although some preferred using NLFC. The results yield suggestions regarding test methods for pediatric bimodal listeners, and considerations regarding validation and audibility of the compressed signal.
Hearing aid use in the contralateral ear of unilaterally implanted children is beneficial. Children and young adults who are fitted bimodally should be tested both in quiet and in complex listening situations to determine bimodal benefit. In the current test battery, the inclusion of frequency compression in the hearing aid fitting does not seem to provide significant improvement beyond standard hearing aid fittings or any bilateral interference symptoms for this group of bimodal listeners.
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ABSTRACT: A coordinated fitting of a cochlear implant (CI) and contralateral hearing aid (HA) for bimodal device use should emphasize balanced audibility and loudness across devices. However, guidelines for allocating frequency information to the CI and HA are not well established for the growing population of bimodal recipients. The study aim was to compare the effects of three different HA frequency responses, when fitting a CI and an HA for bimodal use, on speech recognition and localization in children/young adults. Specifically, the three frequency responses were wideband, restricted high frequency, and nonlinear frequency compression (NLFC), which were compared with measures of word recognition in quiet, sentence recognition in noise, talker discrimination, and sound localization. The HA frequency responses were evaluated using an A B₁ A B₂ test design: wideband frequency response (baseline-A), restricted high-frequency response (experimental-B₁), and NLFC-activated (experimental-B2). All participants were allowed 3-4 weeks between each test session for acclimatization to each new HA setting. Bimodal benefit was determined by comparing the bimodal score to the CI-alone score. Participants were 14 children and young adults (ages 7-21 yr) who were experienced users of bimodal devices. All had been unilaterally implanted with a Nucleus CI24 internal system and used either a Freedom or CP810 speech processor. All received a Phonak Naida IX UP behind-the-ear HA at the beginning of the study. Group results for the three bimodal conditions (HA frequency response with wideband, restricted high frequency, and NLFC) on each outcome measure were analyzed using a repeated measures analysis of variance. Group results using the individual "best bimodal" score were analyzed and confirmed using a resampling procedure. Correlation analyses examined the effects of audibility (aided and unaided hearing) in each bimodal condition for each outcome measure. Individual data were analyzed for word recognition in quiet, sentence recognition in noise, and localization. Individual preference for the three bimodal conditions was also assessed. Group data revealed no significant difference between the three bimodal conditions for word recognition in quiet, sentence recognition in noise, and talker discrimination. However, group data for the localization measure revealed that both wideband and NLFC resulted in significantly improved bimodal performance. The condition that yielded the "best bimodal" score varied across participants. Because of this individual variability, the "best bimodal" score was chosen for each participant to reassess group data within word recognition in quiet, sentence recognition in noise, and talker discrimination. This method revealed a bimodal benefit for word recognition in quiet after a randomization test was used to confirm significance. The majority of the participants preferred NLFC at the conclusion of the study, although a few preferred a restricted high-frequency response or reported no preference. These results support consideration of restricted high-frequency and NLFC HA responses in addition to traditional wideband response for bimodal device users. American Academy of Audiology.04/2015; 26(4):393-407. DOI:10.3766/jaaa.26.4.7
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ABSTRACT: The primary goals of this investigation were (1) to determine the sensitivity of the Phrases in Noise Test (PINT) for identifying children with hearing loss who were at risk for educational difficulties in the classroom, (2) to examine the effects of spatial location of the speech and noise sources on the speech recognition in noise of participants using bilateral cochlear implants (CIs), bilateral hearing aids, or a CI on one ear and hearing aid on the non-implant ear (bimodal stimulation), and (3) to determine the relationship between teacher ratings of educational risk and speech recognition in noise. Twenty-nine children using bilateral CIs, bilateral hearing aids, or bimodal stimulation were tested with the PINT in conditions with speech and noise from the same location or from separate locations in a small room. Teachers of the participants were asked to complete the Preschool Screening Instrument for Targeting Educational Risk (S.I.F.T.E.R.). Average results from the three groups of children suggest significant spatial release from masking, where the spatial separation of speech and noise sources resulted in improved speech-in-noise thresholds. Several medium and strong negative correlations were calculated, where poorer speech-in-noise thresholds on the PINT were related significantly to at-risk Preschool S.I.F.T.E.R. ratings from teachers. In comparison to PINT performance in age-matched children with normal-hearing sensitivity from a previous study, 93% of children in the present study have significantly poorer PINT thresholds. A combination of the PINT and the Preschool S.I.F.T.E.R. may be used by educational audiologists to identify young children with hearing loss who have educational need for classroom accommodations and hearing assistance technology.