Acceptance of noise with monaural and binaural amplification

The present study investigated the effects of monaural and binaural amplification on speech understanding in noise and acceptance of noise for 39 listeners with hearing impairment. Results demonstrated that speech understanding in noise improved with binaural amplification; however, acceptance of noise was not dependent on monaural or binaural amplification for most listeners. These results suggest that although two hearing aids maximize speech understanding ability in noise, most individuals' acceptance of noise, which is directly related to hearing aid use, may not be affected by the use of binaural amplification. It should be noted that monaural amplification resulted in greater acceptance of noise for some listeners, indicating that binaural amplification may negatively affect some individuals' willingness to wear hearing aids. It should also be noted that interaural differences in acceptance of noise might exist for some listeners; therefore, if only one hearing aid is fitted, monaural ANLs should be measured.     

Maturation of binaural interaction components in auditory brainstem responses of young guinea pigs with monaural or binaural conductive hearing loss

Summary Reversible conductive hearing loss created during the first 4 weeks post partum caused marked alterations in the maturation of binaural interaction components in the auditory brainstem responses of guinea pigs. In untreated control animals all three components investigated demonstrated postnatal development in terms of latency shortening that was completed during the first 3 weeks of life. Plugging of both external ear canals caused a significant delay in the maturation of the late component DN₂, where latency values of the controls were reached only 2 weeks after the end of the treatment, i.e. after 6 weeks of life. Monaural deprivation likewise led to a retarded development of peak latencies during the phase of imbalanced sensory imput. After the end of the one-sided conductive hearing loss the maturation process was markedly enhanced, even resulting in latency values for DN₂ and DP₁ that were significantly shorter than those of the controls. This phenomenon persisted until the end of the study period and was the case for both plugged and untreated ears in this group of animals. The time course of latencies in two other groups of experimental animals which were deprived in the same way as adults suggests that the effects observed are due to a sensitive period in the maturation process of the auditory pathway.     

Contribution of monaural and binaural cues to sound localization in listeners with acquired unilateral conductive hearing loss: improved directional hearing with a bone-conduction device

Sound localization in the horizontal (azimuth) plane relies mainly on interaural time differences (ITDs) and interaural level differences (ILDs). Both are distorted in listeners with acquired unilateral conductive hearing loss (UCHL), reducing their ability to localize sound. Several studies demonstrated that UCHL listeners had some ability to localize sound in azimuth. To test whether listeners with acquired UCHL use strongly perturbed binaural difference cues, we measured localization while they listened with a sound-attenuating earmuff over their impaired ear. We also tested the potential use of monaural pinna-induced spectral-shape cues for localization in azimuth and elevation, by filling the cavities of the pinna of their better-hearing ear with a mould. These conditions were tested while a bone-conduction device (BCD), fitted to all UCHL listeners in order to provide hearing from the impaired side, was turned off. We varied stimulus presentation levels to investigate whether UCHL listeners were using sound level as an azimuth cue. Furthermore, we examined whether horizontal sound-localization abilities improved when listeners used their BCD. Ten control listeners without hearing loss demonstrated a significant decrease in their localization abilities when they listened with a monaural plug and muff. In 4/13 UCHL listeners we observed good horizontal localization of 65 dB SPL broadband noises with their BCD turned off. Localization was strongly impaired when the impaired ear was covered with the muff. The mould in the good ear of listeners with UCHL deteriorated the localization of broadband sounds presented at 45 dB SPL. This demonstrates that they used pinna cues to localize sounds presented at low levels. Our data demonstrate that UCHL listeners have learned to adapt their localization strategies under a wide variety of hearing conditions and that sound-localization abilities improved with their BCD turned on.     

聋儿单耳助听与双耳助听听觉记忆的差别

目的评价单耳与双耳配戴助听器聆听时对短时记忆的影响。方法对29名年龄为5-8岁的语训聋儿在单耳助听和双耳助听的情况下分别进行记忆测试。结果双耳助听的听觉记忆与单耳助听的听觉记忆有显著性差异(P<0.01)。左、右耳单耳助听的听觉记忆无显著性差异(P>0.05)。结论被双耳接受的听觉信号经听觉传导通路到达大脑皮层并在大脑皮层中被加工处理的过程中,听觉信号可能被整合而引起了聋儿更好的短时记忆。     

Comparison of speech perception between monaural and binaural hearing in cochlear implant patients

Objective To assess the advantages of binaural hearing for cochlear implant (CI) users using a hearing aid (HA) for the contralateral ear.

Material and Methods The subjects comprised 3 males and 3 females (age range 48–84 years). All of them had been using a CI and HA for >6 months. Their speech perception was examined in quiet using monosyllables and Japanese Hearing in Noise Test (J-HINT) sentences. Speech perception in noise was examined using J-HINT sentences. Late cortical waves were measured while subjects listened to 1 kHz frequent and 2 kHz target tone stimuli. The latency of the event-related potential (P300) wave was compared for monaural and binaural hearing conditions.

Results Three subjects showed significantly better results for binaural than monaural (CI alone) hearing for monosyllables and HINT sentences (p<0.05; paired t-test). Subjects with better speech perception had been using an HA for longer than those with poor performance (18.3 vs 4.0 years). The overall average score was better for binaural than monaural hearing in the speech perception test under quiet and noisy conditions. Comparison of the latency of the P300 wave under monaural and binaural hearing conditions showed a significantly shorter latency for the latter (p=0.02; paired t-test).

Conclusion Although the use of an HA alone showed marginal benefit for CI users, binaural hearing (CI + HA) resulted in a significant improvement in speech perception under various circumstances.     

Comparison of speech perception between monaural and binaural hearing in cochlear implant patients

OBJECTIVE: To assess the advantages of binaural hearing for cochlear implant (CI) users using a hearing aid (HA) for the contralateral ear. MATERIAL AND METHODS: The subjects comprised 3 males and 3 females (age range 48-84 years). All of them had been using a CI and HA for > 6 months. Their speech perception was examined in quiet using monosyllables and Japanese Hearing in Noise Test (J-HINT) sentences. Speech perception in noise was examined using J-HINT sentences. Late cortical waves were measured while subjects listened to 1 kHz frequent and 2 kHz target tone stimuli. The latency of the event-related potential (P300) wave was compared for monaural and binaural hearing conditions. RESULTS: Three subjects showed significantly better results for binaural than monaural (CI alone) hearing for monosyllables and HINT sentences (p < 0.05; paired t-test). Subjects with better speech perception had been using an HA for longer than those with poor performance (18.3 vs 4.0 years). The overall average score was better for binaural than monaural hearing in the speech perception test under quiet and noisy conditions. Comparison of the latency of the P300 wave under monaural and binaural hearing conditions showed a significantly shorter latency for the latter (p = 0.02; paired t-test). CONCLUSIONS: Although the use of an HA alone showed marginal benefit for CI users, binaural hearing (CI+HA) resulted in a significant improvement in speech perception under various circumstances.     

Comparison of monaural and binaural hearing aid use on a trial period basis

Thirty hearing-impaired patients compared monaural and binaural hearing aid use for a period of 4 weeks. Most of them preferred binaural hearing aids in quiet situations, but monaural hearing aids in noisy environments. Follow-up at 6 months revealed that 17 had purchased monaural hearing aids, 8 had purchased binaural hearing aids.     

Performance in children with hearing aids or cochlear implants: bilateral stimulation and binaural hearing

It is well recognised that normal hearing people use their hearing in both ears to locate sounds and to understand speech in complex listening conditions. Whereas it is standard practice to provide two hearing aids to children with bilateral hearing loss, the situation with cochlear implantation is less certain. Questions remain as to what binaural aided functioning is possible for children who use a hearing aid and a cochlear implant in opposite ears (bimodal hearing). The first part of this paper draws on research at the National Acoustic Laboratories to show that children who used bimodal hearing devices obtained binaural advantages in localization. They could also take advantage of head shadow and binaural redundancy for speech intelligibility. The second part presents data showing that some hearing-impaired children may have binaural processing deficits even when bilateral stimulation is provided. Additional strategies may be necessary to develop or enable the use of binaural cues by these children.     

The impact of head angle on monaural and binaural performance with directional and omnidirectional hearing aids

OBJECTIVE: To evaluate the impact of head turn and monaural and binaural fittings on the sentence reception thresholds of hearing-impaired listeners wearing directional and omnidirectional hearing aids. DESIGN: Sentence reception thresholds were measured for 20 listeners fit monaurally and binaurally with behind-the-ear hearing aids set in both directional and omnidirectional modes. All listeners exhibited symmetrical, sloping, sensorineural hearing loss. The aided performance across these four fittings was evaluated for three different head and body angles. The three angles reflected body turns of 0 degrees, 15 degrees, and 30 degrees as measured relative to the primary sound source, with 0 degrees denoting the listener directly facing the sound source. Listeners were instructed to keep their heads in a fixed horizontal position and turn their heads and bodies to face visual targets at the three test angles. Sentences from the Hearing in Noise Test presented with a background of five, spatially separated, uncorrelated samples of cafeteria noise served as test material. All testing was performed in a moderately reverberant (Rt = 631 msec) "living room" environment. RESULTS: Participants generally performed significantly better when fit with directional versus omnidirectional hearing aids, and when fit binaurally versus monaurally across test conditions. The measured "binaural advantage" was reduced with increasing head angle. Participants performed significantly better with a 30 degree head angle than when directly facing the primary speaker. This "head turn advantage" was most prominent for monaural (versus binaural) conditions. Binaural and head turn advantages were not significantly different across directional and omnidirectional modes. CONCLUSIONS: These data provide additional support for the use of directional hearing aids and binaural amplification to improve speech intelligibility in noisy environments. The magnitude of these advantages was similar to that reported in previous investigations. The data also showed that hearing aid wearers achieved significantly better speech intelligibility in noise by turning their heads and bodies to a position in which they were not directly facing the sound source. This head turn advantage was in good agreement with the increase in Directivity Index with head turn and reflected the fact that hearing aids are generally most sensitive to sounds arriving from angles other than directly in front of the hearing aid wearer. Although these data suggest that many monaural hearing aid wearers may significantly improve speech intelligibility in noise through the use of head turn, the interaction between this advantage and the potential loss of visual cues with head turn is unknown.     

A comparison of sound quality judgments for monaural and binaural hearing aid processed stimuli.

Fifteen adults with bilaterally symmetrical mild and/or moderate sensorineural hearing loss completed a paired-comparison task designed to elicit sound quality preference judgments for monaural/binaural hearing aid processed signals. Three stimuli (speech-in-quiet, speech-in-noise, and music) were recorded separately in three listening environments (audiometric test booth, living room, and a music/lecture hall) through hearing aids placed on a Knowles Electronics Manikin for Acoustics Research. Judgments were made on eight separate sound quality dimensions (brightness, clarity, fullness, loudness, nearness, overall impression, smoothness, and spaciousness) for each of the three stimuli in three listening environments. Results revealed a distinct binaural preference for all eight sound quality dimensions independent of listening environment. Binaural preferences were strongest for overall impression, fullness, and spaciousness. Stimulus type effect was significant only for fullness and spaciousness, where binaural preferences were strongest for speech-in-quiet. After binaural preference data were obtained, subjects ranked each sound quality dimension with respect to its importance for binaural listening relative to monaural. Clarity was ranked highest in importance and brightness was ranked least important. The key to demonstration of improved binaural hearing aid sound quality may be the use of a paired-comparison format.     

Improving speech-in-noise recognition for children with hearing loss: Potential effects of language abilities,binaural summation,and head shadow

Abstract

Objective: This study examined speech recognition in noise for children with hearing loss, compared it to recognition for children with normal hearing, and examined mechanisms that might explain variance in children's abilities to recognize speech in noise. Design: Word recognition was measured in two levels of noise, both when the speech and noise were co-located in front and when the noise came separately from one side. Four mechanisms were examined as factors possibly explaining variance: vocabulary knowledge, sensitivity to phonological structure, binaural summation, and head shadow. Study sample: Participants were 113 eight-year-old children. Forty-eight had normal hearing (NH) and 65 had hearing loss: 18 with hearing aids (HAs), 19 with one cochlear implant (CI), and 28 with two CIs. Results: Phonological sensitivity explained a significant amount of between-groups variance in speech-in-noise recognition. Little evidence of binaural summation was found. Head shadow was similar in magnitude for children with NH and with CIs, regardless of whether they wore one or two CIs. Children with HAs showed reduced head shadow effects. Conclusion: These outcomes suggest that in order to improve speech-in-noise recognition for children with hearing loss, intervention needs to be comprehensive, focusing on both language abilities and auditory mechanisms.     

Spatial unmasking and binaural advantage for children with normal hearing, a cochlear implant and a hearing aid, and bilateral implants

The aims of this study were to: (1) determine if spatial unmasking existed and differed for children with normal hearing, a hearing aid and a cochlear implant (CIHA), and bilateral implants (BICI); (2) determine if binaural advantage and headshadow effect differed between children with CIHA and BICI. Results indicated that most of the CIHA and BICI children demonstrated spatial unmasking, though to a lesser degree than children with normal hearing. Results also indicated that the children with BICI demonstrated greater headshadow effect than those with CIHA. The CIHA and BICI children also differed in binaural advantage, which could be due to the differences in headshadow effect and in detection abilities with the hearing aid versus the second implant.     

Unilateral versus bilateral amplification for adults with impaired hearing

This study compared unilateral and bilateral aided speech recognition in background noise in 28 patients being fitted with amplification. Aided QuickSIN (Quick Speech-in-Noise test) scores were obtained for bilateral amplification and for unilateral amplification in each ear. In addition, right-ear directed and left-ear directed recall on the Dichotic Digits Test (DDT) was obtained from each participant. Results revealed that the vast majority of patients obtained better speech recognition in background noise on the QuickSIN from unilateral amplification than from bilateral amplification. There was a greater tendency for bilateral amplification to have a deleterious effect among older patients. Most frequently, better aided QuickSIN performance was obtained in the right ear of participants, despite similar hearing thresholds in both ears. Finally, patients tended to perform better on the DDT in the ear that provided less SNR loss on the QuickSIN. Results suggest that bilateral amplification may not always be beneficial in every daily listening environment when background noise is present, and it may be advisable for patients wearing bilateral amplification to remove one hearing aid when difficulty is encountered understanding speech in background noise.     

Temporal effects in simultaneous pure-tone masking in subjects with high-frequency sensorineural hearing loss

Temporal effects in simultaneous pure-tone masking were studied in three subjects with a high-frequency sensorineural hearing loss. The masker level was generally 80 dB SPL, and the signal level was varied adaptively to threshold. Masker frequency was always 1.2 times the signal frequency, and three different frequency regions were studied: (1) signal and masker in region of normal hearing; (2) signal in region of normal hearing and masker in region of hearing loss; and (3) signal and masker in region of hearing loss. In the first experiment, the masker was either gated synchronously with the 20-ms signal or was presented continuously. The gated-continuous threshold difference was largest when both the masker and signal were in a region of normal hearing; that difference decreased, though was not eliminated, when either the masker or the signal-plus-masker was in a region of hearing loss. In the second experiment, threshold was measured for the 20-ms signal as a function of its temporal position within a 400-ms masker. Consistent with the first experiment, the biggest change in masking over time generally occurred when the signal and masker were in a region of normal hearing. These data suggest that the mechanisms responsible for temporal effects in normal-hearing subjects (and in regions of normal hearing in subjects with a hearing loss) are adversely affected by (even a mild) sensorineural hearing loss. Moreover, these data suggest that what may be most important for a normal temporal effect is the integrity of the frequency region where the masker is presented.     

Amplification considerations for children with minimal or mild bilateral hearing loss and unilateral hearing loss

Children with minimal or mild bilateral hearing loss and unilateral hearing loss are at higher risk for academic, speech-language, and social-emotional difficulties than their normal hearing peers. The choice to fit infants with moderate or greater degrees of bilateral hearing loss has been standard practice for most clinicians, but for those with minimal or mild bilateral hearing loss or unilateral hearing loss, the fitting of hearing technology must be based on limited data. Evidence does not yet exist to support all the management decisions that an audiologist must make upon identifying an infant with minimal or mild bilateral hearing loss or unilateral hearing loss. It is not yet known which children are at the greatest risk for educational problems nor is it known if the provision of early amplification in this population will help a child avoid later difficulties. Some of these considerations and current hearing technology options for children with minimal or mild bilateral hearing loss or unilateral hearing loss are reviewed in this article.