听障儿童双耳双模式配戴的声源定位能力初探*

目的探讨双耳双模式配戴能否帮助听障儿童改善声源定位能力以及哪些因素可能影响双耳双模式声源定位优势的发挥。方法采用强迫二选一任务,比较16名听障儿童在不同助听模式及不同声源角度下的声源定位能力。结果声源位于90°/270°时,38%的被试体现出双耳双模式的声源定位优势;位于45°/315°时,优势比例下降到25%。进一步分析表明,人工耳蜗麦克风的位置以及术前双耳配戴助听器的经验与双耳双模式声源定位优势的发挥密切相关。结论声源定位能力是听障儿童日常生活中的难点,即使双耳双模式配戴,也仅在声源位于左右方时,比单侧耳蜗状态体现出一定优势,随着声源角度的减小,双耳强度差和时间差线索减弱,双耳双模式的声源定位优势也随之减小。人工耳蜗的麦克风须放置在正确位置,否则会影响声源定位能力。此外,术前助听器配戴经验可能会影响听障儿童利用双耳线索的能力。     

BAHA in children and adolescents with unilateral or bilateral conductive hearing loss: a study of outcome

OBJECTIVES: Bilateral BAHAs in adults with bilateral hearing loss (BHL) have proven to be superior to unilateral fitting, in both audiologically measurements and in overall patient satisfaction. There have been no similar studies in children. Furthermore, a recent meta-analysis of children with unilateral hearing loss (UHL) has shown numerous negative consequences. The objectives of the study were to investigate whether fitting of bilateral BAHAs in children with conductive BHL give additional hearing benefits, to investigate the effects of unilateral hearing aids in children with conductive UHL, and to identify different aspects of auditory problems in children with conductive UHL or BHL. STUDY DESIGN: This was a prospective study involving 22 children with either conductive UHL (unaided or with unilateral hearing aid) or conductive BHL (with unilateral or bilateral BAHAs) and 15 controls. METHODS: Baseline audiometry, tone thresholds in a sound field, speech recognition in noise and sound localization were tested without, and with unilateral and bilateral hearing aids. Two questionnaires, MAIS & MUSS and IOI-HA, were completed. RESULTS: Two problem areas were identified in the children with hearing impairment: in reactions to sounds and in intelligibility of speech. An additional BAHA in the children with BHL resulted in a tendency to have improved hearing in terms of better sound localization and speech recognition in noise. Fitting of unilateral hearing aids in the children with UHL gave some supplementary benefit in terms of better speech recognition in noise but no positive effect on ability to localize sound could be detected. Even so, all children fitted with hearing aids - either unilaterally or bilaterally - reported a positive outcome with their devices in the self-assessment questionnaire. CONCLUSIONS: Children with either UHL or BHL displayed several problems within the hearing domain. Fitting of bilateral BAHAs in children with BHL and of a single-sided hearing aid in children with UHL appears to have some supplementary audiological benefits and also renders high patient satisfaction. In order to investigate the possible supplementary effects of hearing aids, a 3-month trial of BAHA on Softband, either unilaterally or bilaterally, may be of value in children with conductive UHL or BHL, respectively.     

Bilateral bone-anchored hearing aids (BAHAs): an audiometric evaluation

OBJECTIVES: Since the technique to implant bone-anchored hearing aids (BAHAs) with the use of osseointegrated implants was developed in 1977, more than 15,000 patients have been fitted with BAHAs worldwide. Although the majority have bilateral hearing loss, they are primarily fitted unilaterally. The main objective of this study was to reveal benefits and drawbacks of bilateral fitting of BAHAs in patients with symmetric or slight asymmetric bone-conduction thresholds. The possible effects were divided into three categories: hearing thresholds, directional hearing, and binaural hearing. STUDY DESIGN: Prospective study of 12 patients with bilateral BAHAs. METHODS: Baseline audiometry, directional hearing, speech reception thresholds in quiet and in noise, and binaural masking level difference were tested when BAHAs were fitted unilaterally and bilaterally. RESULTS: Eleven of the 12 patients used bilateral BAHAs on a daily basis. Tests performed in the study show a significant improvement in sound localization with bilateral BAHAs; the results with unilateral fitting were close to the chance level. Furthermore, with bilateral application, the improvement of the speech reception threshold in quiet was 5.4 dB. An improvement with bilateral fitting was also found for speech reception in noise. CONCLUSIONS: Overall, the results with bilateral fitted BAHAs were better than with unilaterally fitted BAHA; the benefit is not only caused simply by bilateral stimulation but also, to some extent, by binaural hearing. Bilateral BAHAs should be considered for patients with bilateral hearing loss otherwise suitable for BAHAs.     

言语、空间与听觉质量量表在老年听力损失者助听器验配中的应用

目的探讨言语、空间与听觉质量量表(speech,spatial and qualities of hearing scale,SSQ)用于老年听力损失患者佩戴助听器的效果评估作用。方法以100例老年感音神经性听力损失者(60~90岁)为研究对象,采用横断面研究和前瞻性研究,其中,无助听器使用经验者44例(75.8±8.1岁,气导纯音平均听阈59.8±13.3 dB HL)、有助听器使用经验者34例(77.5±6.3岁,气导纯音平均听阈64.5±17.8 dB HL,助听器佩戴时间大于三个月)进行横断面研究;22例(74.3±8.6岁,气导纯音平均听阈58.1±12.6 dB HL)首次配戴助听器者进行前瞻性研究;二组参与横断面研究者进行一次SSQ评估,前瞻性研究组分别在助听前和佩戴助听器1个月后进行二次SSQ评估,均采用面对面问答方式用SSQ量表评估三组受试者在言语理解能力、空间定位能力和声音聆听质量方面的变化。结果横断面研究结果显示,有助听经验组SSQ问卷言语理解(97.29±23.43分)、空间听觉(131.94±19.27分)、声音质量(143.53±20.31分)和总分(372.76±51.92分)均显著高于无助听经验组(分别为58.66±30.13、99.41±37.09、108.09±43.28、266.16±78.18分)。前瞻性研究结果显示,受试者初次佩戴助听器一个月后的SSQ问卷言语理解(106.27±13.86分)、空间听觉(136.00±14.09分)、声音质量(151.73±13.91分)和总分(394.00±34.70分)均显著高于佩戴助听器前(分别为65.64±21.89、115.09±17.17、111.91±25.41、292.64±45.58分),横断面研究和前瞻性研究结果均显示,老年听力损失患者佩戴助听器后在言语理解能力、空间声源定位能力和声音聆听质量方面均有显著改善(P<0.05)。结论SSQ量表可以有效评估老年听力损失患者助听器使用效果;老年听力损失患者佩戴助听器后在言语理解能力、空间定位能力和声音聆听质量方面均有显著提高。     

Advantages of directional hearing aid microphones related to room acoustics.

In this study, two types of hearing aids were used. Both aids had the same frequency characteristics for frontal sound, but one employed an omnidirectional microphone and the other a directional microphone. The frequency characteristics of both hearing aids were measured for five azimuths on KEMAR and in situ in 12 normal-hearing subjects. For these subjects we also determined the speech reception threshold (SRT) with background noise in two rooms with different reverberation times. The direction of the speech stimuli was always frontal; the direction of the noise was varied. Additionally, directional hearing was measured with short noise bursts from eight loudspeakers surrounding the subject. In the less reverberant room, sounds coming from behind were less amplified by the hearing aid with the directional microphone than by the one with the omnidirectional microphone. In this room the monaural SRT values were largely determined by the level of the background noise. For the directional hearing aids there was an extra binaural advantage which depended on the direction of the background noise. Only for low-frequency noise bursts was directional hearing better with directional hearing aids. In the more reverberant room, no distinct differences between the frequency characteristics of the two hearing aid types were measured. However, a systematic difference between monaural SRT values measured through the two hearing aids was found. This difference was independent of noise azimuth. In conclusion, hearing aid(s) with a directional microphone showed no disadvantages and clear advantages under specific conditions.     

The cocktail party effect

The main advantages of wearing 2 ear level hearing aids are the possibilities of directional hearing and of avoiding the acoustical head shadow. These effects are rather easy to measure. There exists another effect which would seem, at first sight, to be of major importance: The fact that in an environment of hampering sounds one understands better with 2 ears than with only 1: the cocktail party effect (CPE).

As in already described [Kuyper and de Boer, 1969] there are many ways to measure and even to define the CPE. The most natural way (and the best if one investigates hearing aids) is to use loudspeakers. Carhart [1965] describes a method which avoids the effect of head shadow. Unfortunately it was impossible for us to obtain in double prothetized subjects an effect which was greater than the variance.

In order to avoid this variance we improved a method developed by Feldmann in 1963, and in this way succeeded in obtaining significant results for each single subject.

Applying this method on prothetized subjects, forced us to use the telephone coil instead of the microphone of the post-aural hearing-aids.     

Comparison of hearing aids over the 20th century

OBJECTIVE: To measure hearing aid performance using circuitry representative of the major eras of technological advancement during the 20th century. DESIGN: Twenty subjects with audiometric profiles consistent with hearing aid candidacy were fit with each of seven hearing aids. No directional microphones were used and binaural benefit was not assessed. Each hearing aid was fit to the strategy or fitting scheme of the era, or that which was intended by the presenting manufacturer. Electroacoustic and/or real ear measures of gain, output, bandwidth, and distortion were obtained. Objective outcome measures assessing speech perception in backgrounds of noise were obtained. Subjective outcome measures of sound quality and ease of listening were obtained in the laboratory and in real life settings. RESULTS: Electroacoustic and real ear measures indicate that gain and bandwidth have increased, and output and distortion have decreased with current electronic aids. Speech perception ability across the different outcome measures showed significantly poorer performance with the body and linear hearing aids when input levels were high; when input levels were low, outcome measures with hearing aids using a dynamic range compression were not negatively affected. At the most adverse signal to noise ratios, none of the hearing aids was shown to be superior. Measured bandwidth did not correlate highly with speech perception ability for any of the objective outcome measures used. For the subjective measures of sound quality done in a blinded manner, no significant differences were found across different listening situations for current hearing aids. CONCLUSIONS: The two most important factors for aided speech perception appear to be the audibility and distortion of the signal. No current compression scheme proved superior with the outcome measures used in this investigation.     

Bone conductive implants in single-sided deafness

Conclusion: Bone conduction implants (BCIs) have been shown to partially restore some of the functions lost when binaural hearing is missing, such as in subjects with single-sided deafness (SSD). The use of a single BCI needs to be recommended by a clinician based on thorough counselling with the SSD subject. Objectives: To perform an overview of the present capabilities of BCIs for SSD and to evaluate the reliability of the audiological evaluation for assessing speech recognition in noise and sound localization cues, which are major problems related to the loss of binaural hearing. Methods: Nine subjects with SSD who received BCI implants underwent a preoperative audiological evaluation that included sound field speech audiometry, word recognition score (WRS) testing and sound localization testing in quiet and in noise. They were also tested for the accuracy of their directional word recognition in noise and their subjective perceptions of their hearing difficulties using the APHAB questionnaire. Results: The mean maximum accuracy of word discrimination was 65.5% in the unaided condition and 78.9% in the BCI-aided condition. Sound localization in noise was better with the BCI than in the unaided condition, especially when the stimulus and noise were presented on the same side as the implanted ear. The accuracy of directional word recognition showed an improvement with the BCI with respect to the unaided condition on the BCI side, with either the stimulus in the implanted ear and the noise in the contralateral ear or with both the stimulus and noise presented to the implanted ear.     

Sound localization. Part II: a clinical procedure

Difficulty in localizing sound has been shown to be associated with severe unilateral hearing impairment, middle-ear conditions and lesions of the cerebello-pontine angle. This was in contrast to the performance of subjects with cochlear lesions and certain brain conditions who had mainly normal ability to localize sound. The investigation appeared to indicate that a sound localization test in the horizontal plane using low frequency stimuli may be a useful addition to the test battery employed in the differential diagnosis of cochlear and retrocochlear lesions involving the cerebello-pontine angle.     

小儿游戏测听难点的应对策略 --附一例7岁聋儿病例

小儿行为测听是小儿听力评估重要的主观测听方法，广泛用于小儿听力损失的诊断．助听器选配和人工耳蜗调试。测试需要孩子对声音产生主动自愿反应并通过某种动作表现出来，从而判断听阈。测试过程需要孩子的主动配合，因此孩子的年龄．运动能力．智力水平．交往能力和测试者的测试技巧等都影响着小儿听力图的获得和测试结果的可靠性。一般年龄越小，挑战性越大，但也有例外。本文分析一例7岁聋儿游戏测听困难的原因以及测试策略以供借鉴。     

Advantages of Binaural Amplification to Acceptable Noise Level of Directional Hearing Aid Users

Objectives

The goal of the present study was to examine whether Acceptable Noise Levels (ANLs) would be lower (greater acceptance of noise) in binaural listening than in monaural listening condition and also whether meaningfulness of background speech noise would affect ANLs for directional microphone hearing aid users. In addition, any relationships between the individual binaural benefits on ANLs and the individuals'' demographic information were investigated.

Methods

Fourteen hearing aid users (mean age, 64 years) participated for experimental testing. For the ANL calculation, listeners'' most comfortable listening levels and background noise level were measured. Using Korean ANL material, ANLs of all participants were evaluated under monaural and binaural amplification with a counterbalanced order. The ANLs were also compared across five types of competing speech noises, consisting of 1- through 8-talker background speech maskers. Seven young normal-hearing listeners (mean age, 27 years) participated for the same measurements as a pilot testing.

Results

The results demonstrated that directional hearing aid users accepted more noise (lower ANLs) with binaural amplification than with monaural amplification, regardless of the type of competing speech. When the background speech noise became more meaningful, hearing-impaired listeners accepted less amount of noise (higher ANLs), revealing that ANL is dependent on the intelligibility of the competing speech. The individuals'' binaural advantages in ANLs were significantly greater for the listeners with longer experience of hearing aids, yet not related to their age or hearing thresholds.

Conclusion

Binaural directional microphone processing allowed hearing aid users to accept a greater amount of background noise, which may in turn improve listeners'' hearing aid success. Informational masking substantially influenced background noise acceptance. Given a significant association between ANLs and duration of hearing aid usage, ANL measurement can be useful for clinical counseling of binaural hearing aid candidates or unsuccessful users.     

The Effects of Microphone Spacing on Auditory Localization

The localization ability of 10 normally hearing adults was determined under varying microphone separations and varying sound source azimuths. The stimuli (white noise bursts) were prerecorded, after being transduced through 'body' hearing aids and then played to the subjects over headphones. Results indicated that there was an improvement in localization ability for all azimuth conditions when the microphones were spaced wider than 12.7 cm apart (15.2–30.5 cm). The smaller the separations (5.5–12.7 cm), the poorer the localization. Localization was always poorer at 30° azimuth (the smallest used) than at any of the other azimuths (0°, 30°, 60°, 90° right and left), regardless of microphone spacing. Implications are made about the relation of these findings to the use of binaural body aids on infants and young children.     

Directivity and noise reduction in hearing aids: speech perception and benefit

Hearing aid.AimTo compare the performance, benefit and satisfaction of users of ITE, CIC and BTE digital hearing aid with noise reduction and omnidirectional and directional microphones.Method34 users of hearing aid were evaluated by means of speech perception in noise tests and APHAB and IOI self assessment questionnaires. Prospective study.ResultsBetter results were obtained by users of ITE, CIC and directional hearing aids, however, no statistical significance was found between the groups.ConclusionDirectivity improved speech perception in noise and benefit in daily life situations.     

Separating signal and noise in vibrotactile devices for the deaf

This paper briefly reviews a series of experiments demonstrating that a sound-to-touch transform of signal and noise may be perceptually separated by providing tactile cues for sound localization. Following this, three experiments are reported in which it is shown that such stereotactile cues are available if two vibrotactile devices (Minifonators, produced by Siemens Co. Ltd.), are used instead of one. With this system, subjects were able to attend to a target signal (male voice) in white noise and when a female voice was presented simultaneously. This ability depended upon a sufficient spatial separation of the target and noise in acoustic space. These findings appear to have applications in the design of tactile hearing aids and cochlear implants when used in noisy environments or when more than one sound is present.     

Sound localization measured by eye-tracking

Objective: To introduce a new method of measuring sound localization ability based on eye-tracking and to test this method by analysing the influence of mild induced conductive hearing loss on sound localization. Design: Sound signals were presented from different angles, and the participant's responses were measured using an eye-tracking device. For validation, a comparison of responses to visual stimuli was performed. To test the clinical application of this method, a mild conductive hearing loss was simulated, and the impact of this change on sound localization was measured. Study sample: Fifteen participants. Results: The system provided repeatable measurements, and there was a good correlation of sound and visual signals. A large number of trials could be completed fairly rapidly. Following the induced conductive hearing loss, a decline of 5.5° in the accuracy of sound localization in the horizontal plane was found towards the side of the non-impaired ear for frontal presentations. Conclusions: Quantifying sound localization by eye-tracking was found to be feasible, fast and accurate. A mild conductive hearing loss caused a slight degradation of sound localization accuracy within the 30° frontal sector, which is in good agreement with results found using methods requiring more extensive instrumentation.     

Unaided and aided performance with a directional open-fit hearing aid

Differences in performance between unaided and aided performance (omnidirectional and directional) were measured using an open-fit behind-the-ear (BTE) hearing aid. Twenty-six subjects without prior experience with amplification were fitted bilaterally using the manufacturer's recommended procedure. After wearing the hearing aids for one week, the fitting parameters were fine-tuned, based on subjective comments. Four weeks later, differences in performance between unaided and aided (omnidirectional and directional) were assessed by measuring reception thresholds for sentences (RTS in dB), using HINT sentences presented at 0° with R-Space^TM restaurant noise held constant at 65dBA and presented via eight loudspeakers set 45° apart. In addition, the APHAB was administered to assess subjective impressions of the experimental aid.

Results revealed that significant differences in RTS (in dB) were present between directional and omnidirectional performance, as well as directional and unaided performance. Aided omnidirectional performance, however, was not significantly different from unaided performance. These findings suggest for the hearing aids and experimental condition used in this study, a patient would require directional microphones in order to perform significantly better than unaided or aided with omnidirectional microphones, and that performance with an omnidirectional microphone would not be significantly better than unaided. Finally, the APHAB-aided scores were significantly better than unaided scores for the EC, BN, RV, and AV subscales indicating the subjects, on average, perceived the experimental aid to provide significantly better performance than unaided, and that aided performance was more aversive than unaided.     

Quantification of directional benefit across different polar response patterns

The purpose of this study was to assess the relationship between the directivity of a directional microphone hearing aid and listener performance. Hearing aids were fit bilaterally to 19 subjects with sensorineural hearing loss, and five microphone conditions were assessed: omnidirectional, cardioid, hypercardioid, supercardioid, and "monofit," wherein the left hearing aid was set to omnidirectional and the right hearing aid to hypercardioid. Speech perception performance was assessed using the Hearing in Noise Test (HINT) and the Connected Speech Test (CST). Subjects also assessed eight domains of sound quality for three stimuli (speech in quiet, speech in noise, and music). A diffuse soundfield system composed of eight loudspeakers forming the corners of a cube was used to output the background noise for the speech perception tasks and the three stimuli used for sound quality judgments. Results indicated that there were no significant differences in the HINT or CST performance, or sound quality judgments, across the four directional microphone conditions when tested in a diffuse field. Of particular interest was the monofit condition: Performance on speech perception tests was the same whether one or two directional microphones were used.     

Full time directional versus user selectable microphone modes in hearing aids

OBJECTIVE: The purpose of this experiment was to systematically examine hearing aid benefit as measured by speech recognition and self-assessment methods across omnidirectional and directional hearing aid modes. These data were used to compare directional benefit as measured by speech recognition in the laboratory to hearing aid wearer's perceptions of benefit in everyday environments across full-time directional, full-time omnidirectional, and user selectable directional fittings. Identification of possible listening situations that resulted in different self reported hearing aid benefit as a function of microphone type was a secondary objective of this experiment. DESIGN: Fifteen adults with symmetrical, sloping sensorineural hearing loss were fitted bilaterally with in-the-ear (ITE) directional hearing aids. Measures of hearing aid benefit included the Profile of Hearing Aid Benefit (PHAB), the Connected Sentence Test (CST), the Hearing in Noise Test (HINT), and a daily use log. Additionally, two new subscales were developed for administration with the PHAB. These subscales were developed to specifically address situations in which directional hearing aids may provide different degrees of benefit than omnidirectional hearing aids. Participants completed these measures in three conditions: omnidirectional only (O), directional only with low-frequency gain compensation (D), and user-selectable directional/omnidirectional (DO). RESULTS: Results from the speech intelligibility in noise testing indicated significantly more hearing aid benefit in directional modes than omnidirectional. PHAB results indicated more benefit on the background noise subscale (BN) in the DO condition than in the O condition; however, this directional advantage was not present for the D condition. Although the reliability of the newly proposed subscales is as yet unknown, the data were interpreted as revealing a directional advantage in situations where the signal of interest was in front of the participant and a directional disadvantage in situations where the signal of interest was behind the listener or localization was required. CONCLUSIONS: Laboratory directional benefit is reflected in self-assessment measures that focus on listening in noise when the sound source of interest is in front of the listener. The use of a directional hearing aid mode; however, may have either a positive, a neutral, or a negative impact on hearing aid benefit measured in noisy situations, depending on the specific listening situation.