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Journal ArticleDOI

Speech recognition in noise using bilateral open-fit hearing aids: the limited benefit of directional microphones and noise reduction.

TL;DR: The significant, though limited, advantage of directional microphones and the absence of additional significant improvement by a noise reduction algorithm should be considered when fitting open-fit hearing aids.
Abstract: To investigate speech recognition performance in noise with bilateral open-fi t hearing aids and as reference also with closed earmolds, in omnidirectional mode, directional mode, and directional mode in conjunction with noise reduction Design: A within-subject design with repeated measures across conditions was used Speech recognition thresholds in noise were obtained for the different conditions Study sample: Twenty adults without prior experience with hearing aids All had symmetric sensorineural mild hearing loss in the lower frequencies and moderate to severe hearing loss in the higher frequencies Results: Speech recognition performance in noise was not signifi cantly better with an omnidirectional microphone compared to unaided, whereas performance was signifi cantly better with a directional microphone (16 dB with open fi tting and 44 dB with closed earmold) compared to unaided With open fi tting, no signifi cant additional advantage was obtained by combining the directional microphone with a noise reduction algorithm, but with closed earmolds a signifi cant additional advantage of 08 dB was obtained Conclusions: The signifi cant, though limited, advantage of directional microphones and the absence of additional signifi cant improvement by a noise reduction algorithm should be considered when fi tting open-fi t hearing aids

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Citations
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Journal ArticleDOI
TL;DR: The effects of hearing loss on neural activity is described to illustrate the reasons why current hearing aids are insufficient and to motivate the use of new technologies to explore directions for improving the next generation of devices.

82 citations

Journal ArticleDOI
TL;DR: The occlusion effect and its consequences for perception while using hearing aids are described, and the advantages and disadvantages of open compared with closed fittings and their impact on the fitting process are addressed.
Abstract: One of the main issues in hearing-aid fittings is the abnormal perception of the user's own voice as too loud, "boomy," or "hollow." This phenomenon known as the occlusion effect be reduced by large vents in the earmolds or by open-fit hearing aids. This review provides an overview of publications related to open and closed hearing-aid fittings. First, the occlusion effect and its consequences for perception while using hearing aids are described. Then, the advantages and disadvantages of open compared with closed fittings and their impact on the fitting process are addressed. The advantages include less occlusion, improved own-voice perception and sound quality, and increased localization performance. The disadvantages associated with open-fit hearing aids include reduced benefits of directional microphones and noise reduction, as well as less compression and less available gain before feedback. The final part of this review addresses the need for new approaches to combine the advantages of open and closed hearing-aid fittings.

46 citations


Cites methods from "Speech recognition in noise using b..."

  • ...6 and 3dB, depending on the specific measurement configurations applied in the studies (Fabry, 2006; Flynn, 2004; Klemp & Dhar, 2008; Kuk et al., 2005b; Magnusson et al., 2013; Valente & Mispagel, 2008), especially when attempts were made to maximize the directional effect at high frequencies....

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  • ...…1.6 and 3dB, depending on the specific measurement configurations applied in the studies (Fabry, 2006; Flynn, 2004; Klemp & Dhar, 2008; Kuk et al., 2005b; Magnusson et al., 2013; Valente & Mispagel, 2008), especially when attempts were made to maximize the directional effect at high frequencies....

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Journal ArticleDOI
TL;DR: No significant effect of HA use was observed after 6 months of follow-up in patients with AD and HL and a smaller cognitive decline should be obtained with HA use.
Abstract: Background/objective This study evaluated the cognitive benefit of hearing aids (HA) in older patients with Alzheimer's disease (AD) and hearing loss (HL) after a 6- and 12-month period of utilization. Methods A multicenter double-blind randomized placebo-controlled trial was conducted in patients aged more than 65 years. A group was equipped with active HA for 6 months (active group) and a second group had placebo HA for 6 months (placebo group) followed by a secondary activation phase for a further 6 months (semi crossover procedure). Both groups were retested after a 12-month period. The primary endpoint was the change from baseline of the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS Cog) after a 6-month period in both groups and after 6 months of secondary HA activation in the placebo group. A smaller cognitive decline should be obtained with HA use; an increase in ADAS Cog score of less than 6 points was defined a success. Results Fifty-one patients aged 68 to 99 years were included; 38 attended the 6-month visit: 18 in the active group and 20 in the placebo group. At 6 months, 14 (82.4%) successes were noticed in the active group, and 15 (88.2%) in the placebo group (p = 1.0); delta ADAS Cog in the active group was 1.8±5.3 and 1.3±5.3 in the placebo group (p = 0.8). In the placebo group, after the secondary HA activation, no significant improvement was observed. Conclusion No significant effect of HA use was observed after 6 months of follow-up in patients with AD and HL.

40 citations

Book ChapterDOI
01 Jan 2016
TL;DR: It is concluded that modern hearing aids can be effective in restoring audibility and providing acceptable loudness and listening comfort, but they are still of limited effectiveness in improving the intelligibility of speech in noisy situations.
Abstract: This chapter reviews the general types of signal processing that are used in modern digital hearing aids. The focus is on concepts underlying the processing rather than on details of the implementation. The signal processing can be classified into three broad classes: (1) Processing to apply frequency- and level-dependent amplification to restore audibility and provide acceptable loudness, based on the hearing profile of the individual (usually the audiogram but sometimes taking into account the results of loudness scaling) and the preferences of the individual. Frequency lowering can be considered as an additional method for restoring the audibility of high-frequency sounds. (2) Sound cleaning, for example, partial removal of stationary noises or impulse sounds and reduction of acoustic feedback. Noise reduction may be achieved using both single-microphone and multiple-microphone algorithms, but only the latter have been shown to improve intelligibility. (3) Environment classification for automatically controlling the settings of a hearing aid in different listening situations. It is concluded that modern hearing aids can be effective in restoring audibility and providing acceptable loudness and listening comfort, but they are still of limited effectiveness in improving the intelligibility of speech in noisy situations.

32 citations

Journal ArticleDOI
TL;DR: Suggestions are made about why AR platforms may offer ideal affordances to compensate for hearing loss, and how research-focused AR platforms could help toward better understanding of the role of hearing in everyday life.
Abstract: An augmented reality (AR) platform combines several technologies in a system that can render individual "digital objects" that can be manipulated for a given purpose. In the audio domain, these may, for example, be generated by speaker separation, noise suppression, and signal enhancement. Access to the "digital objects" could be used to augment auditory objects that the user wants to hear better. Such AR platforms in conjunction with traditional hearing aids may contribute to closing the gap for people with hearing loss through multimodal sensor integration, leveraging extensive current artificial intelligence research, and machine-learning frameworks. This could take the form of an attention-driven signal enhancement and noise suppression platform, together with context awareness, which would improve the interpersonal communication experience in complex real-life situations. In that sense, an AR platform could serve as a frontend to current and future hearing solutions. The AR device would enhance the signals to be attended, but the hearing amplification would still be handled by hearing aids. In this article, suggestions are made about why AR platforms may offer ideal affordances to compensate for hearing loss, and how research-focused AR platforms could help toward better understanding of the role of hearing in everyday life.

19 citations


Cites background from "Speech recognition in noise using b..."

  • ..., the most advanced devices provide only modest additional benefits (Humes et al. 1999; Larson et al. 2000; Magnusson et al. 2013; Brons et al. 2014; Cox et al. 2014; Picou et al. 2015)....

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References
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Journal ArticleDOI
TL;DR: The mean-squared level of each digitally recorded sentence was adjusted to equate intelligibility when presented in spectrally matched noise to normal-hearing listeners, and statistical reliability and efficiency suit it to practical applications in which measures of speech intelligibility are required.
Abstract: A large set of sentence materials, chosen for their uniformity in length and representation of natural speech, has been developed for the measurement of sentence speech reception thresholds (sSRTs). The mean‐squared level of each digitally recorded sentence was adjusted to equate intelligibility when presented in spectrally matched noise to normal‐hearing listeners. These materials were cast into 25 phonemically balanced lists of ten sentences for adaptive measurement of sentence sSRTs. The 95% confidence interval for these measurements is ±2.98 dB for sSRTs in quiet and ±2.41 dB for sSRTs in noise, as defined by the variability of repeated measures with different lists. Average sSRTs in quiet were 23.91 dB(A). Average sSRTs in 72 dB(A) noise were 69.08 dB(A), or −2.92 dB signal/noise ratio. Low‐pass filtering increased sSRTs slightly in quiet and noise as the 4‐ and 8‐kHz octave bands were eliminated. Much larger increases in SRT occurred when the 2‐kHz octave band was eliminated, and bandwidth dropped below 2.5 kHz. Reliability was not degraded substantially until bandwidth dropped below 2.5 kHz. The statistical reliability and efficiency of the test suit it to practical applications in which measures of speech intelligibility are required.

1,909 citations


"Speech recognition in noise using b..." refers background or methods in this paper

  • ...Considering the known variability in speech test results, Abbreviations ANOVA Analysis of variance DI Directivity index HA Hearing aid HINT Hearing in noise test IOI-HA International outcome inventory for hearing aids NR Noise reduction PB Phonemically balanced SD Standard deviation SRT Speech recognition threshold this sample size was estimated to be suffi cient for detecting clinically signifi cant differences between conditions....

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  • ...Speech recognition performance was obtained with HINT sentences for the different conditions....

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  • ...Therefore, we used Hagerman ’ s sentences, although these sentences are somewhat unnatural in comparison with everyday sentences such as the HINT sentences....

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  • ...E-mail: lennart.magnusson@neuro.gu.se (Received 14 December 2011; accepted 20 June 2012) ISSN 1499-2027 print/ISSN 1708-8186 online © 2013 British Society of Audiology, International Society of Audiology, and Nordic Audiological Society DOI: 10.3109/14992027.2012.707335 in noise test (HINT) (Nilsson et al, 1994) was used to determine speech recognition thresholds (SRTs) in noise....

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  • ...Speech recognition thresholds were obtained with HINT sentences in four HA conditions; omnidirectional, omnidirectional with NR, directional, and directional with NR. Speech material was presented directly in front of the subjects and noise was presented from three loudspeakers placed at 90 ° , 180 ° , and 270 ° ....

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Journal ArticleDOI
TL;DR: A list of ten spoken Swedish sentences was computer edited to obtain new lists with exactly the same content of sound, but with new sentences, to investigate the equality in intelligibility of some of the lists.
Abstract: A list of ten spoken Swedish sentences was computer edited to obtain new lists with exactly the same content of sound, but with new sentences. A noise was synthesized from the speech material by the computer to produce exactly the same spectrum of speech and noise. The noise was also amplitude modulated by a low frequency noise to make it sound more natural. This material was tested monaurally on 20 normal-hearing subjects. The equality in intelligibility of some of the lists was investigated. Repeated threshold measurements in noise showed a standard deviation of 0.44 dB when the learning effect was outbalanced. Only a small part of the learning effect was due to learning of the word material. Intelligibility curves fitted to the data points in noise and without noise showed maximum steepnesses of 25 and 10%/dB respectively. At constant signal to noise ratio (S/N) the best performance was achieved at a speech level of 53 dB.

408 citations


"Speech recognition in noise using b..." refers background or methods in this paper

  • ...Hagerman (1982) developed this test material by recording one original list with a female speaker, and then he compiled the various lists by combining the words differently between the sentences....

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  • ...An improved speech-to-noise ratio of 1 dB corresponds to an improved recognition score of up to 25 percentage points (pp) for Hagerman ’ s sentence test, which has a very steep psychometric function (Hagerman, 1982)....

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  • ...The Swedish speech test material, Hagerman ’ s sentences (Hagerman, 1982), was used to determine SRTs in noise....

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Journal ArticleDOI
TL;DR: The Denmark sentence test DANTALE II was developed in analogy to the Swedish sentence test by Hagerman and the German Oldenburg sentence test as a new Danish sentence test in noise to determine the speech reception threshold in noise (SRT, i.e. the signal-to-noise ratio that yields 50% intelligibility).
Abstract: The Danish sentence test DANTALE II was developed in analogy to the Swedish sentence test by Hagerman and the German Oldenburg sentence test as a new Danish sentence test in noise to determine the speech reception threshold in noise (SRT, i.e. the signal-to-noise ratio (SNR) that yields 50% intelligibility). Each sentence is generated by a random combination of the alternatives of a base list. This base list consists of 10 sentences with the same syntactical structure (name, verb, numeral, adjective, object). The test sentences were recorded and segmented in such a way that the coarticulation effects were taken into account in order to achieve a high perceived sound quality of the resynthesized sentences: 100 sentences were recorded, each coarticulation between each word and the 10 possible following word alternatives were recorded, and the correct coarticulation was used to generate the test sentences. Word-specific speech recognition curves were measured for each recorded word to optimize the homogeneit...

248 citations

Journal ArticleDOI
TL;DR: The results suggest that the signal-to-noise ratio is optimized when binaural hearing aids with directional microphones are used in rooms with short reverberation times.
Abstract: The signal-to-noise ratio necessary for a constant performance level was determined for normally hearing and hearing-impaired subjects under three levels of reverberation (0.3, 0.6, and 1.2 s) with...

232 citations


"Speech recognition in noise using b..." refers background in this paper

  • ...Previous studies have reported a signifi cantly enhanced signal-to-noise ratio can be achieved by using directional microphones (e.g. Hawkins & Yacullo, 1984; Valente et al, 1995; Ricketts & Dahr, 1999; Ricketts et al, 2003)....

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Journal ArticleDOI
TL;DR: The participants in the Eriksholm Workshop on “Measuring Outcomes in Audiological Rehabilitation Using Hearing Aids” debated three issues that are reported in this article, including the concept of generating a brief universally applicable outcome measure.
Abstract: The participants in the Eriksholm Workshop on "Measuring Outcomes in Audiological Rehabilitation Using Hearing Aids" debated three issues that are reported in this article. First, it was agreed that the characteristics of an optimal outcome measure vary as a function of the purpose of the measurement. Potential characteristics of outcome self-report tools for four common goals of outcome measurement are briefly presented to illustrate this point. Second, 10 important research priorities in outcome measurement were identified and ranked. They are presented with brief discussion of the top five. Third, the concept of generating a brief universally applicable outcome measure was endorsed. This brief data set is intended to supplement existing outcome measures and to promote data combination and comparison across different social, cultural, and health-care delivery systems. A set of seven core items is proposed for further study.

228 citations


Additional excerpts

  • ...Although the slopes of the psychometric functions for speech materials that are comprised by everyday sentences are commonly shallower, e.g. American English HINT (Nilsson et al, 1994): 9.7 pp/dB, and Swedish HINT (Hallgren et al, 2006): 17.9 pp/dB, it is clear that just one dB improvement of the speech-to-noise ratio would make great difference in speech recognition performance....

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  • ...This questionnaire, which originally was developed in English (Cox et al, 2000), has been translated to several other lang uages, including Swedish (Cox et al, 2002)....

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The significant, though limited, advantage of directional microphones and the absence of additional significant improvement by a noise reduction algorithm should be considered when fitting open-fit hearing aids.