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1
Moore, Calvin. "Remote hearing aid fitting." Master's thesis, University of Cape Town, 2012. http://hdl.handle.net/11427/12025.
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Includes abstract.<br>Includes bibliographical references.<br>Hearing aid fitting is a costly process due to the cost of hearing aids, audiologists' hourly rates, and large travelling distances caused by regionally sparse audiologist populations. This dissertation is focused on the development of a system which aims at reducing the severity of this problem.
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Johnson, Earl E. "Fitting a Hearing Aid to Conductive Hearing Loss and Realistic Expectations When Fitting a Hearing Aid to Sensorineural Hearing Loss." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/1740.
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Allan, Louise. "Factors Associated With Hearing Aid Disuse In New Zealand/Aotearoa." Thesis, University of Canterbury. Communication Disorders, 2015. http://hdl.handle.net/10092/10775.
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Introduction: Despite the advantages of using a hearing aid (HA), only 1 out of 5 individuals who could benefit from a (HA) actually use one (World Health Organization, 2012). If an individual does not use a HA then it may impact on their quality of life, as well as others around them (Chia et al., 2007). Therefore it is important to understand why individuals do not use HAs after obtaining them. To date, there has been no study that investigates the reasons for HA disuse in the New Zealand population.
Methods: Two groups of adults with hearing impairment were recruited: HA users (N = 35) and HA disusers (N = 35). Six self-report questionnaires, three audiometric tests and two other body function measures were compared between the groups.
Results: Several variables differentiated HA users from disusers, these significant variables were: cognition, understanding speech in noise, acceptance of noise, age at testing, education, hearing assistance technology (HAT) use, HA satisfaction, self-efficacy, accepted need, application for HA subsidy, HA outcomes, stages-of-change, perceived environmental influence, follow-up support and hearing related activity limitations/participation restrictions (AL/PR).
Discussion: The clinical value of identifying factors related to HA disuse is so clinicians can identify “red flags” for disuse before the client stops using their HAs. By identifying these red flags, rehabilitation can be tailored around the clients’ needs; before the negative consequences of an untreated hearing impairment is felt.
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Larsen, Emil Wiik, and Espen Oldervoll Moberg. "Hearing Aid for Social Situations." Thesis, Norwegian University of Science and Technology, Department of Electronics and Telecommunications, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9593.
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<p>Conventional hearing aids perform badly in environments with reverberation and noise. In this paper the use of microphone arrays as hearing aids to increase directivity and signal-to-noise ratio (SNR) in a noisy environment are evaluated. A portable microphone array prototype is constructed to test beamforming algorithms in a real environment. Delay and sum beamforming, sub-band beamforming and an experimental type of binaural beamforming is implemented in real-time using the digital signal processor ADSP-BF533. Results from testing showed that a four microphone array using sub-band beamforming outperforms delay and sum beamforming using the same number of microphones. The results also showed that it is possible to obtain binaural impression of the array output and source localization using the proposed binaural technique called beamspreading.</p>
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Kengmana, Caitlin. "Hearing aid satisfaction among adults with hearing impairment in New Zealand." Thesis, University of Canterbury. Communication Disorders, 2015. http://hdl.handle.net/10092/10414.
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Introduction: This study investigated hearing aid (HA) satisfaction among adult with hearing impairment (HI) in New Zealand. This study aimed to answer three questions: 1) What are the current HA satisfaction levels amongst adult HA users in New Zealand? 2) How do the satisfaction findings of this study compare with other HA satisfaction data? 3) What client factors are related to HA satisfaction?
Method: Participants were recruited prospectively. They completed a questionnaire prior to HA fitting and a questionnaire three months post-fitting. Information was collected on: age, gender, HA experience, HI severity, hearing ability, change in hearing ability, hearing handicap, communication self-efficacy, change in communication self-efficacy, HA self-efficacy, HA usage, and number of appointments. HA satisfaction was measured via the Satisfaction with Amplification in Daily Life questionnaire (SADL; Cox & Alexander, 1999).
Results: Data were collected for 47 participants. Of these, 91.5% fell within or above the normative range for global satisfaction established by Cox & Alexander (1999). The mean SADL scores were predominantly high compared to previous research. Satisfaction with negative features of HAs was especially high in this study. However satisfaction with the service and cost of HAs was low compared to other research. SADL scores were found to significantly relate to age, gender, change in hearing ability, hearing handicap, communication self-efficacy, change in communication self-efficacy, and HA self-efficacy.
Conclusions: Results differed from previous research indicating that HA satisfaction may differ over time and across countries. Assessing HA satisfaction in a comprehensive standardised way, as opposed to with a single-item measure, can help identify important related factors. Targeting identified variables such as communication and HA self-efficacy may lead to improved treatment efficacy.
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McKenzie, Andrew Rayner. "An adaptive response hearing aid for high frequency hearing loss." Thesis, University of Southampton, 1988. https://eprints.soton.ac.uk/52267/.
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A new approach to the evaluation of hearing aid fitting has suggested that an adaptive frequency/gain characteristic is subjectively more beneficial for patients with precipitous high frequency hearing loss, listening to speech in the various quiet and noisy situations encountered in everyday life. The development and evaluation of such a hearing aid is described. Parameters for the operation of the adaptive response mechanism were determined experimentally by means of subjective listening tests using subjects with precipitous high frequency hearing loss. Software was compiled to implement these parameters on a specially designed, computer-controlled, master hearing aid system in real time. A novel evaluation procedure was developed in order to assess the benefits provided by this system in terms of objective speech discrimination measures and subjective judgements in simulations of real life listening conditions. Uncertainty about the effects of binaural hearing aid fitting and, in particular, the lack of scientific evidence of any subjective advantages to be gained, led to a secondary study of the benefits of fitting a preferred monaural response binaurally. The hypothesis that the adaptive frequency response hearing aid is more appropriate than a standard fixed frequency response aid for people with precipitous high frequency hearing loss, listening to speech in the variety of quiet and noisy situations encountered in everyday life, was partially upheld in that it was preferred by a significant number of patients with 4kHz hearing loss greater than, or equal to, 65 dBHL. However, for patients with less severe high frequency hearing loss, a flat frequency response was preferred. A secondary hypothesis, that binaural fitting of a person's preferred monaural hearing aid response provides further increases in benefit over those found for the monaural fitting, was upheld. Further findings with important implications for hearing aid fitting, both monaural and binaural, are discussed together with important directions for future work.
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GOODRUM, ANN ELAINE. "HEARING AID MAINTENANCE IN NURSING HOMES." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1053696984.
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Bell, D., Earl E. Johnson, J. Robinson, et al. "Hearing Aid Evaluation Clinic Systems Redesign." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/1729.
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Bell, D., Earl E. Johnson, J. Robinson, et al. "Hearing Aid Evaluation Clinic Systems Redesign." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/1753.
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McCreery, Katie, and Marc A. Fagelson. "Factors Influencing Hearing Healthcare and Hearing Aid Access in Southern Appalachia." Digital Commons @ East Tennessee State University, 2016. https://dc.etsu.edu/etsu-works/1957.
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Although hearing loss is among the most common chronic conditions in the U.S., many individuals never speak to a healthcare provider about it. Thus, evaluation and rehabilitation services remain underutilized. Even mild hearing loss may result in decreased quality of life, social isolation, and decreased selfsufficiency. The purpose of this study was to assess factors that influence hearing healthcare access and hearing aid acquisition by individuals in Southern Appalachia. The identification of barriers to hearing healthcare access may help audiologists tailor care to this group‘s specific needs. The Hearing Handicap Inventory for Adults (HHIA), a questionnaire assessing self-perceived hearing handicap (a major determinant in help-seeking behaviors in people with hearing loss), was administered along with a researcher-designed survey. The researcher-designed survey was comprised of two forms. Form A asked questions specific to unaided individuals, with half pertaining to individuals with normal hearing, and the other half pertaining to individuals with unaided hearing loss. Form B asked questions specific to hearing aid users. Both forms collected demographic information. Survey participants were recruited from the Remote Area Medical (RAM) clinic held in Bristol, TN on May 1-3, 2015. HHIAs and surveys were obtained from 127 individuals. Two major barriers to hearing healthcare were identified: financial barriers and transportation-related barriers. 62% of respondents reported a household income of $20,000 or less, with an average household size of 2.6 members. Because hearing aids must often be purchased out of pocket, individuals in this income bracket may not be able to afford assistive devices. Some individuals in Southern Appalachia live far from the urban centers where audiologists tend to be located. Although the unaided individuals surveyed indicated they could travel some distance for hearing healthcare services, more than half indicated that they would be unable to travel more than an hour. In contrast, more than half of the aided group indicated that they were required to travel more than an hour for services. Since rural areas often lack public transportation, costs associated with traveling a long distance using personal transportation may present a barrier to hearing healthcare access. These barriers may be at least partially remediated by financial aid programs, telehealth services, and self-help/support group initiatives. The Bristol RAM clinic, in partnership with ETSU‘s audiology department, attempts to overcome these barriers by providing free hearing screenings and low-cost amplification options to individuals with hearing loss living in rural areas.
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Rutledge, Kate Laura. "A Music Listening Questionnaire for Hearing Aid Users." Thesis, University of Canterbury. Communication Disorders, 2009. http://hdl.handle.net/10092/3194.
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To date, very few studies have been conducted focusing on ratings of music and music listening experience of hearing aid (HA) users. This study aimed to collect more detailed and descriptive information via a questionnaire, on the music listening experience and ratings of musical sounds from postlingually deafened adults. The following hypotheses were posed: (i) ratings for music from HA users who have been assessed for a cochlear implant (HA-CI group) will be worse than those who have not been assessed for a CI (HA-NCI group); and (ii) HA users with a moderate or worse hearing loss (Moderate+ subgroup) will provide lower ratings for music than those with a mild hearing loss (Mild subgroup). A questionnaire by She (2008), was modified for this study, and subsequently called the University of Canterbury Music Listening Questionnaire – HA version (UCMLQ_HA). The questionnaire was divided into the following seven sections: music listening and music background, sound quality ratings, music styles, music preferences, music recognition, factors affecting music listening enjoyment, and a music training programme. Thirteen HA-CI recipients and 98 HA-NCI recipients returned the questionnaire. The HA-NCI group was divided into two subgroups: mild hearing loss (n = 51), and moderate or worse hearing loss (Moderate+; n = 47). Essentially findings were consistent with hypothesis one, but only partially consistent with hypothesis two. The HA-CI group provided lower ratings for ‘pleasantness’ and ‘naturalness’ of instruments (p = 0.007), and found music styles to be less ‘pleasant’ (p < 0.001) than the HA-NCI group. For musical styles, the HA-CI group preferred solo performers whereas the HA-NCI group preferred groups of performers. In addition to ratings of music, the HA-CI group provided significantly lower ratings for music listening (p = 0.001), and overall music enjoyment (p = 0.021) than the HA-NCI group. For the comparisons between the Mild and Moderate+ subgroups, the Mild subgroup found Instruments to sound significantly ‘less noisy’ (p < 0.001) and ‘less sharp’ (p < 0.001) than the Moderate+ subgroup. The Moderate+ subgroup provided higher ratings for overall enjoyment of listening to music with HAs than the Mild subgroup (p = 0.044). Both subgroups rated the drum kit (the lowest rated Instrument) to be significantly less pleasant and less natural than all other Instruments. It was also found that all musical styles were significantly more pleasant than Pop/Rock. There were similarities between the groups for music preferences; the male singer was significantly preferred over female singers (p = 0.021), and low-pitched instruments were significantly preferred over high-pitched instruments (p = 0.04). Classical music was also selected as the style that sounded the best with their HAs and listened to the most often. Almost all of the respondents indicated that they would like music in general to sound it would to those with normal hearing (97.1%). Close to 30% indicated that they would be interested in an MTP and would like it to focus on a wide range of music and feature commonly known tunes. In addition, training sessions should consist of two 30 minute sessions per week. Overall this study indicates that ratings of music differ with level of hearing loss to some degree. The general consensus was that music did not sound as they would expect it to sound to a person with normal hearing, and that respondents would like to enjoy listening to music more.
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Davis, Lynne Allison. "Experienced and inexperienced hearing aid users' preference for and performance with damped and undamped hearing aids /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487844948075337.
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Salamatmanesh, Mina. "Pediatric Hearing Aid Use: Factors and Challenges." Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42325.
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BACKGROUND: Population-based universal newborn hearing screening (UNHS) has been widely implemented in the developed world to ensure early detection of permanent hearing loss (HL) and improve the quality of speech and language outcomes of children with HL. Full-time hearing aid (HA) use is crucial for successful early intervention; most families face many challenges and uncertainties related to their child’s HA use in the early years after HA fitting. To our knowledge, there is limited information on HA use in children from Canadian settings, and there is no research using data logging records to examine a child’s HA use in the Canadian pediatric setting.
GOALS: This thesis compromised three inquiries, which aimed to 1) conduct a systematic review of pediatric HA use; 2) examine HA use trends based on data logging records; 3) explore needs and challenges of HA use in young children from clinicians’ perspective.
METHODOLOGY: Following a systematic review of the current literature, this doctoral research used a mixed methodology approach to examine the objectives of inquiries 2 and 3. In inquiry 2, the HA use trends in a Canadian pediatric population were explored through a retrospective chart review. In inquiry 3, the needs and challenges of HA use in the pediatric population were studied through focus group discussions with healthcare professionals involved in providing services to children with HL and their families.
RESULTS: In the first inquiry (systematic review), 15 studies met the review criteria. Only four studies reported HA use based on data logging records. Age, degree of HL and parents’ education level were the most frequently reported factors associated with a child’s amount of HA use. In the second inquiry, our study sample consisted of 80 children. The study results showed an average of 7.3 hours (SD: 4.27) of HA use in the first data logging session, among all 80 cases. There was a significant association between a child’s chronological age, laterality of HL, duration of HA use and the amount of HA use. For the last inquiry, 15 clinicians from the CHEO audiology clinic participated in focus group discussion. Clinicians indicated that key items for better HA use outcomes included child-specific factors, family-related factors, and a multidisciplinary team approach.
CONCLUSION: Through this research program, we confirmed various factors, including child’s characteristics, family-related factors, and a child setting, could affect a child’s average daily HA use. From this thesis, we learned that attention should be given to families' unique challenges to provide efficient solutions in an understandable format according to their specific needs and challenges. This thesis lays a foundation for future research on HA use in early childhood, one of the important factors associated with a successful early intervention program in hearing rehabilitation.
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Eddie, Sarah Joan. "Hearing Aid Usage in Different Listening Environments." Thesis, University of Canterbury. Communication Disorders, 2007. http://hdl.handle.net/10092/1418.
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This study investigates the listening environments of hearing aid users by employing the data logging capacity of their hearing aids. The idea that a hearing aid user's listening environments are important in prescribing desired hearing aid features has been discussed in the literature, however, investigation of listening environments has been limited in the past as it has relied mainly on subjective recordings. Data logging, the capacity of a hearing aid to continuously store information regarding time spent in different programs, listening environments, and microphone modes, is now available in a number of hearing aid models, and therefore provides an objective tool for studying a hearing aid user's listening environments. The data logging information from fifty-seven new hearing aid wearers, including 50 males and 7 females (mean age = 68 years, SD = 11.3), was obtained during the first routine clinic follow-up session for each individual. Measures of time spent in different listening environments, microphone modes, and overall sound levels, were analyzed. Hearing aid usage time was found to be highest in "Speech Only" situations (44.8%), followed by "Quiet" (26.7%), "Noise Only" (16.3%) and "Speech in Noise" (12.3%) situations. The majority of the hearing aid users' time was spent in "Surround" microphone mode (74.3%), followed in order by "Split" (22.3%) and "Full" (3.5%) directional modes. Results of two separate two-way ANOVAs revealed no significant age effect either on time spent in different listening environments [F(3,49) = 0.7, p= 0.5] or on time spent in different microphone modes [F(3,20) = 0.6, p= 0.6]. These findings provide empirical evidence regarding the general listening pattern of hearing aid users, which can be used as a starting point when troubleshooting problems experienced by hearing aid clients, or assessing a user's need for various hearing aid features.
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Flack, Linda. "Acoustic feedback in the hearing aid system." Thesis, University of Aberdeen, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296620.
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This study concentrated on the problem of instability in a hearing aid system due to acoustic feedback. A mathematical model of feedback in the hearing aid system was developed. It was based on that of Egolf (1989. J. Acoust. Soc. Am. 85:1 pp 454-467), but included numerous feedback paths replacing the single path used by Egolf. A computer based analysis tool was designed and built that could measure feedback in the <I>in-situ</I> hearing aid. The feedback measurement system used two different methods to deliver the signal to the hearing aid: direct (or wired) and telecoil. The two methods were tested on partially hearing children at a routine hearing aid assessment clinic. The results demonstrated that where the <I>in-situ </I>hearing aid had a higher tendency to feedback there was a corresponding increase in the level of feedback signal measured. There was also a decrease in the feedback ratio with increasing age of the subject. The effect of changes to the hearing aid system were studied using both the feedback measurement system and the mathematical model. Several parameters were found to have a significant effect on the feedback levels. Some however where found to have little or no effect. The phase response was similarly altered differently by different parameters. The mathematical model and system were thus tested and validated. The system was unique because it collected phase information as well as the feedback ratio, it could also include the subject's own hearing aid in the analysis. The model was unique because it looked at the numerous sources of feedback. Both were able to evaluate the acoustic properties of earmoulds and tubing.
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Greenberg, Julie Elise. "A real-time adaptive-beamforming hearing aid." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/14504.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1989.<br>Includes bibliographical references (leaves 67-69).<br>by Julie Elise Greenberg.<br>M.S.
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Welker, Daniel Patrick. "A real-time binaural adaptive hearing aid." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12043.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.<br>Includes bibliographical references (leaves 102-103).<br>by Daniel Patrick Welker.<br>M.S.
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Amanda, Tannor Ophelia. "Hearing aid combined with virtual reality function." Thesis, Boston, USA, 2020. http://openarchive.nure.ua/handle/document/11840.
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In this paper the structure scheme of a smart hearing aid with augmented reality was proposed. This scheme consists of 6 blocks: sensor (microphone), ADC, microprocessor or microcontroller, battery, Bluetooth module, speaker. Such a device should not only improve hearing but also increase the psychological confidence of a person. The next stage of work is the development of an electrical circuit diagram of the device and the assembly of the prototype
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Johnson, Earl E. "Are Larger Hearing Aid Receivers Really Noisier?" Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/1974.
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Question: I've been fitting a lot of receiver-in-canal (RIC) products, and when I have a patient with good low-frequency hearing, I like to use the smaller gain receiver option because I worry about the larger gain receiver being noisier. Sometimes though, use of the smaller gain receiver makes it difficult to fit prescriptive targets for moderately-severe to severe high frequency hearing loss thresholds. Should I be concerned about larger receivers being noisier?
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Bredenkamp, Corné-Louise. "Age related hearing loss and conversation before and after hearing aid fitting /." Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-10222007-143520.
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Johnson, Earl E. "A Comparison of Generic Hearing Aid Prescriptive Methods from Pediatric Hearing Aid Fittings: Estimates of Loudness and Speech Intelligibility." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/2248.
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Wong, C. W. "Preferred frequency responses for Cantonese-speaking hearing aid users /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2204131X.
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Hasan, Syed Shabih. "Mobile ecological momentary assessment for hearing aid evaluation." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5494.
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Hearing loss can significantly hinder an individual's ability to engage socially and, when left untreated, can lead to anxiety, depression, and even dementia. The most common type of hearing loss is sensor-neural hearing loss that is treated using hearing aids (HAs). However, a significant fraction of individuals that may benefit from using HA do not use them and, the satisfaction of those that do, is only around 60%. Today, we have only a limited understanding regarding the factors that contribute to the low adoption and satisfaction rates. This is a limitation of existing laboratory-based assessment methods that cannot accurately predict the performance of HAs in the real-world as they do not fully reproduce the complexities of real-world environments.
There four core contributions of my PhD thesis:
i) the development new computer-based methods for assessing HAs in the real-world. Our approach is based on the insight that HA performance is intrinsically dependent on the context in which a HA is used. A context includes characteristics of the listening activity, social context, and acoustic environment. To evaluate this hypothesis, we have developed AudioSense, a system that uses mobile phones to jointly characterize the context of users and the performance of HAs.
ii) We provide the first instance of characterization of the auditory lifestyle of hearing aid users, and the relationships that exist between the context and hearing aid outcomes.
iii) We utilize the subjective data collected using AudioSense to build novel models that can predict the success of hearing aid prescriptions for new and experienced users. We also quantitatively prove the importance of collecting contextual information for evaluating hearing aids.
iv) We use the objective audio data collected with AudioSense to predict contextual information like acoustic activity and noise level. This provides us a way to intelligently infer contextual information automatically and reduce the burden on the study participants.
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Eager, Katrise Mary. "Rehabilitation of unilateral profound sensorineural hearing loss with a bone anchored hearing aid." University of Western Australia. School of Surgery, 2010. http://theses.library.uwa.edu.au/adt-WU2010.0061.
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The long-term outcomes of subjects fitted with a bone anchored hearing aid (BAHA) for a unilateral profound sensorineural hearing loss (UPSHL) are still evolving. Previous studies have focused on the comparison between shortterm outcomes obtained with hard-wired contralateral routing of signal (CROS) hearing aids and those obtained with BAHA devices. Published results on subjects who have worn their BAHA devices for UPSHL for more than twelve months are limited. This study explored the long-term outcomes of adults fitted with a BAHA for UPSHL. The aims were firstly to examine subjects' pre-operative and postoperative speech perception in quiet and noise, as well as administer two standardised questionnaires, the Abbreviated Profile of Hearing Benefit (APHAB) and the Glasgow Hearing Aid Benefit Profile (GHABP). The second aim was to evaluate the responses of implanted subjects following the preoperative test protocols using a supplementary questionnaire, the Single Sided Deafness Questionnaire (SSDQ). The third aim was to monitor the subjects' implant or repair issues. In addition, questionnaire results were compared to subjects who underwent pre-operative assessment but were not implanted. All subjects had a UPSHL resulting from various aetiologies including vestibular schwannoma or other skull base tumour removal, viral infections, cochlear trauma, idiopathic sudden hearing loss, and Meniere's disease. There was a significant difference between the implanted groups' pre- and post-operative outcomes measures, indicating a treatment effect from the fitting of the BAHA device. No significant changes were found with the non-implanted groups' longterm outcome measures in regards to their perceived hearing difficulties. No significant correlations were found between outcome measures and gender, age of fitting, length of deafness, or ear affected for either group.
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Johnson, Earl E. "Evidences Surrounding Hearing Aid Selection, Fitting, and Evaluation." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/1749.
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This sessions covers a wide range of topics related to the selection and fitting of hearing aids. Areas addressed extend also to the technical operation of hearing aid amplification parameters and components. In general, the session proceeds through five steps pertaining to the hearing aid fitting process covering identification of the candidate, measurements prior to selection, selection, verification and validation. The session addresses a number of specific points within each of the steps regarding specific patient assessments, patient characteristics, hearing aid amplification parameters, hearing aid measurements and outcome measurements. The depth of coverage will offer a session of novel information, but the breadth of coverage will allow for the discussion of many topic areas of interest to audiologists fitting hearing aids in a variety of clinical settings.
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Keller, E., Earl E. Johnson, and C. Noe. "A Comparison of Hearing Aid Drying Device Technologies." Digital Commons @ East Tennessee State University, 2009. https://dc.etsu.edu/etsu-works/1751.
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Gilbert, Alison Mary. "Limiting Noise Exposure Associated with Hearing Aid Use." PDXScholar, 1995. https://pdxscholar.library.pdx.edu/open_access_etds/5193.
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Industrial workers who have sustained hearing losses often wear hearing aids on the job in order to hear their co-worker's speech. However they risk damaging their hearing further by amplifying the high levels of background noise typical of such environments. The Occupational Safety and Health Administration (OSHA) has established guidelines to protect workers' hearing. A maximum allowable level of 90 dBA averaged over a period of eight hours is considered safe. Wearing hearing aids on the job may expose an individual to a considerably higher levels, however no guidelines as to maximum allowable levels of amplified noise exist at this time. This study evaluated the performance of four hearing aids in noise to determine which would provide appropriate amplification without exceeding the OSHA maximum. The instruments were adjusted to provide 14 different frequency responses and placed on the Knowles Mannequin for Acoustic Research (KEMAR). A microphone in the position of KEMAR's eardrum recorded amplified levels of taped industrial noise. A sound level meter integrated the levels to give the OSHA Time Weighted Average (TWA), simulating the acoustic effect of an 8-hour noise exposure on an industrial worker. Amplified noise remained below the OSHA maximum (90 dBA) in 2 of the 14 hearing aid conditions studied. Noise amplified by the Argosy Expander, an experimental noise-reducing hearing aid, remained below the OSHA maximum when the instrument was set to provide minimum gain and maximum noise reduction. The Argosy 3-Channel Clock also maintained amplified noise at a safe level when adjusted to provide gain only in a limited frequency region. Noise amplified by the Danavox Aura X programmed to provide a TILL response remained within one dB of the OSHA maximum. This study demonstrated that it is possible to use amplification in environments with constant background noise without risking additional noise-induced hearing loss. Two hearing aids were proven effective in maintaining amplified industrial noise at safe levels, however determining their effect on speech intelligibility in noise is beyond the scope of this study. Further research is needed to address this issue.
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Johnson, Earl E. "Essentials of Modern Hearing Aids: Selection, Fitting, and Verification." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/5569.
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Meagher, Kelsey Marie. "Effects of hearing aid processing on cortical auditory evoked potentials in normal hearing individuals." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/64172.
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Cortical auditory evoked potentials (CAEPs) are currently being investigated as a tool for validation in hearing aid fittings. There is some conflicting evidence regarding the usefulness of CAEPs in this capacity. CAEPs are influenced by stimulus parameters and hearing aids can change these parameters in an unpredictable manner. The purpose of this study was to investigate the effect of rise time after hearing aid processing on the CAEP of 23 normal hearing participants. Two different duration stimuli (60 ms and 120 ms) were processed by three different hearing aids and the output of each hearing aid was recorded. The stimulus parameters were measured for each condition and the stimuli were presented to each participant through an insert earphone. Two blocks of stimuli were used (1) Raw (varied SNR and intensity) and (2) Equalized/Filtered (equalized SNR and intensity). The electroencephalography (EEG) was recorded and the P1-N1-P2 amplitudes and latencies were measured for each condition. A three-factor ANOVA was conducted to observe the effects of (1) rise time, (2) duration, and (3) SNR. A main effect of rise time was observed on the N1-P2 amplitude. This result indicated that hearing aid processing can increase the rise time enough to elicit a decrease in the N1-P2 amplitude. No effects were observed on amplitudes or latencies of the N1-P2 with the alternative stimulus parameters (SNR and duration). Prior to using CAEPs clinically for validation of hearing aid fittings, normative standards should be established. This ensures that differences in the N1-P2 amplitudes are due specifically to audibility and not to the altered stimulus parameter (i.e., after hearing aid processing). Further research should also be conducted on individuals with hearing loss to see if the effects observed in this study would be present with this population. In addition, comparisons of behavioural and CAEP methods of validation would be helpful in determining the validity and reliability of using these methods clinically.<br>Medicine, Faculty of<br>Audiology and Speech Sciences, School of<br>Graduate
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Johnston, Kristin Nicole. "Music perception of hearing impaired listeners effects of hearing aid settings and personality factors /." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041026.
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Sundewall, Thorén Elisabet. "Internet Interventions for Hearing Loss : Examing rehabilitation, self-report measures and internet use for hearing-aid users." Doctoral thesis, Linköpings universitet, Institutionen för klinisk och experimentell medicin, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-103824.
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In the future, audiological rehabilitation of adults with hearing loss will be more available, personalized and thorough due to the possibilities offered by the internet. By using the internet as a platform it is also possible to perform the process of rehabilitation in a cost-effective way. With tailored online rehabilitation programs containing topics such as communication strategies, hearing tactics and how to handle hearing aids it might be possible to foster behavioral changes that will positively affect hearing aid users. Four studies were carried out in this thesis. The first study investigated internet usage among adults with hearing loss. In the second study the administration format, online vs. paper- and pencil, of four standardized questionnaires was evaluated. Finally two randomized controlled trials were performed evaluating the efficacy of online rehabilitation programs including professional guidance by an audiologist. The programs lasted over five weeks and were designed for experienced adult hearing-aid users. The effects of the online programs were compared with the effects of a control group. It can be concluded that the use of computers and the internet overall is at least at the same level for people with hearing loss as for the general age-matched population in Sweden. Furthermore, for three of the four included questionnaires, the participants’ scores remained the same across formats. It is however recommended that the administration format remain consistent across assessment points. Finally, results from the two concluding intervention studies provide preliminary evidence that the internet can be used to deliver education and rehabilitation to experienced hearing aid users who report residual hearing problems and that their problems are reduced by the intervention; however the content and design of the online rehabilitation program requires further investigation.
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Sporck, Karen Kieley. "Effect of real-ear verification on hearing aid benefit /." Full-text of dissertation on the Internet (7.38 MB), 2010. http://www.lib.jmu.edu/general/etd/2010/doctorate/sporcksk/sporcksk_doctorate_04-19-2010_01.pdf.
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Bail, Rebecca A. "The post-auricular canal hearing aid a better solution? /." Connect to resource, 2006. http://hdl.handle.net/1811/6584.
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Thesis (Honors)--Ohio State University, 2006.<br>Title from first page of PDF file. Document formatted into pages: contains vii, 59 p.; also includes graphics. Includes bibliographical references (p. 58-59). Available online via Ohio State University's Knowledge Bank.
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Chiu, Eva M. C. "The effect of hearing aid distortion on sound quality." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/mq21037.pdf.
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Segar, Allyson Adrianne. "Personality type and self-perception of hearing aid benefit." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3739.
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Thesis (Au. D) -- University of Maryland, College Park, 2006.<br>Thesis research directed by: Hearing and Speech Sciences. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ng, Hoi Ning Elaine. "Cognition in Hearing Aid Users : Memory for Everyday Speech." Doctoral thesis, Linköpings universitet, Institutet för handikappvetenskap (IHV), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98286.
Full textAbstract:
The thesis investigated the importance of cognition for speech understanding in experienced and new hearing aid users. The aims were 1) to develop a cognitive test (Sentence-final Word Identification and Recall, or SWIR test) to measure the effects of a noise reduction algorithm on processing of highly intelligible speech (everyday sentences); 2) to investigate, using the SWIR test, whether hearing aid signal processing would affect memory for heard speech in experienced hearing aid users; 3) to test whether the effects of signal processing on the ability to recall speech would interact with background noise and individual differences in working memory capacity; 4) to explore the potential clinical application of the SWIR test; and 5) to examine the relationship between cognition and speech recognition in noise in new users over the first six months of hearing aid use. Results showed that, for experienced users, noise reduction freed up cognitive resources and alleviated the negative impact of noise on memory when speech stimuli were presented in a background of speech babble spoken in the listener’s native language. The possible underlying mechanisms are that noise reduction facilitates auditory stream segregation between target and irrelevant speech and reduces the attention captured by the linguistic information in irrelevant speech. The effects of noise reduction and SWIR performance were modulated by individual differences in working memory capacity. SWIR performance was related to the self-reported outcome of hearing aid use. For new users, working memory capacity played a more important role in speech recognition in noise before acclimatization to hearing aid amplification than after six months. This thesis demonstrates for the first time that hearing aid signal processing can significantly improve the ability of individuals with hearing impairment to recall highly intelligible speech stimuli presented in babble noise. It also adds to the literature showing the key role of working memory capacity in listening with hearing aids, especially for new users. By virtue of its relation to subjective measures of hearing aid outcome, the SWIR test can potentially be used as a tool in assessing hearing aid outcome.<br>Avhandlingens övergripande mål var att studera kognitionens betydelse för talförståelse hos vana och nya hörapparatsanvändare. Syftena var att 1) utveckla ett kognitivt test (Sentence-final Word Identification and Recall, eller SWIR test) för att mäta en brusreducerande algoritms effekt på bearbetningen av tydligt tal (vardagsmeningar); 2) att med hjälp av SWIR testet undersöka huruvida hörapparatens signalbehandling påverkade återgivningen av uppfattat tal hos vana hörapparatsanvändare; 3) att utvärdera om effekten av signalbehandling på förmågan att komma ihåg tal påverkas av störande bakgrundsljud samt individuella skillnader i arbetsminnets kapacitet; 4) att undersöka den potentiella kliniska tillämpningen av SWIR testet och 5) att undersöka förhållandet mellan kognition och taluppfattning i störande bakgrundsljud hos nya hörapparatsanvändare under de första sex månaderna med hörapparater. Resultaten visade att för vana hörapparatsanvändare lindrade brusreduceringen det störande ljudets negativa inverkan på minnet när meningar presenterades i form av irrelevant tal på deltagarnas modersmål. De möjliga underliggande mekanismerna är att brusreducering underlättar diskriminering av de auditiva informationsflödena mellan det som ska uppfattas och det som är irrelevant, samt minskar graden av uppmärksamhet som fångas av den språkliga informationen i det irrelevanta talet. Effekterna av brusreducering och resultaten av SWIR var beroende av individuella skillnader i arbetsminnets kapacitet. Resultaten av SWIR har också samband med det självrapporterade utfallet av hörapparatsanvändning. För nya användare spelar arbetsminnets kapacitet initialt en viktigare roll för taluppfattning i störande bakgrundsljud, innan anpassningen till hörapparatens förstärkning skett, än efter sex månader. Denna avhandling visar för första gången att hörapparatens signalbehandling kan signifikant förbättra möjligheten för individer med hörselnedsättning att minnas tydligt tal, som presenteras i störande bakgrundsljud. Avhandlingen bidrar till litteraturen med en diskussion om hur arbetsminnets kapacitet spelar roll i taluppfattning med hörapparat, i synnerhet för nya användare. Med stöd av dess samband med det självrapporterade utfallet, kan SWIR testet användas som redskap i bedömning av hörapparaters effekt.
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Olson, Anne D. "AUDITORY TRAINING AT HOME FOR ADULT HEARING AID USERS." UKnowledge, 2010. http://uknowledge.uky.edu/gradschool_diss/11.
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Research has shown that re-learning to understand speech in noise can be a difficult task for adults with hearing aids (HA). If HA users want to improve their speech understanding ability, specific training may be needed. Auditory training is one type of intervention that may enhance listening abilities for adult HA users.
The purpose of this study was to examine the behavioral effects of an auditory training program called Listening and Communication Enhancement (LACE™) in the Digital Video Display (DVD) format in new and experienced HA users. No research to date has been conducted on the efficacy of this training program.
An experimental, repeated measures group design was used. Twenty–six adults with hearing loss participated in this experiment and were assigned to one of three groups: New HA + training, Experienced HA + training or New HA – control. Participants in the training groups completed twenty, 30 minute training lessons from the LACE™ DVD program at home over a period of 4-weeks. Trained group participants were evaluated at baseline, after 2-weeks of training and again after 4- weeks of training. Participants in the control group were evaluated at baseline and after 4-weeks of HA use.
Findings indicate that both new and experienced users improved their understanding of speech in noise after training and perception of communication function. Effect size calculations suggested that a larger training effect was observed for new HA users compared to experienced HA users. New HA users also reported greater benefit from training compared to experienced users. Auditory training with the LACE ™ DVD format should be encouraged, particularly among new HA users to improve understanding speech in noise.
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Waterman, Niall. "The design and development of a digital hearing aid." Thesis, University of Ulster, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261058.
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McCelland, Emily, Julia McDowell, Sherri Smith, Kim Schairer, and Marc A. Fagelson. "Hearing Aid Outcomes in Patients with Posttraumatic Stress Disorder." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etsu-works/7812.
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Objectives: The purpose of this study was to compare hearing difficulties and hearing aid outcomes in veterans with Posttraumatic Stress Disorder (PTSD) to a group of veterans with no medical diagnosis of PTSD. Our hypothesis was that veterans with PTSD would have poorer hearing aid outcomes in certain domains (e.g., those related to loudness or interactions with the environment) relative to patients without PTSD. Assessing these differences could help identify unique factors that may lead to the development of tailored aural rehabilitation for hearing aid users with PTSD.
Design: This descriptive study employed subjective outcome measures and surveys; the Abbreviated Profile for Hearing Aid Benefit (APHAB) served as the primary outcome measure. An additional questionnaire was developed to assess views of the subjects’ hearing in unaided and aided conditions in an effort to explore the relation between hearing aid benefit and PTSD symptoms. A total of 60 veterans with sensorineural hearing loss and bilateral hearing aid use were recruited from the Audiology Clinic at the James H. Quillen Veterans Affairs Medical Center in Mountain Home, TN. Participants were divided into two groups of subjects either with or without PTSD (n=30 in each). Diagnosis of PTSD was confirmed via a chart review of the veteran’s medical record.
Results: Results from the APHAB revealed a significant difference between groups in global benefit scores as well as the aversiveness subscale in the unaided condition. Overall, the PTSD group showed lower benefit scores, however outcomes indicated that both groups received benefit when aided. Results from the study questionnaire showed a significant difference between the two groups in both unaided and aided conditions for the questions focused on hyper-arousal and re-experiencing symptoms.
Conclusions: Hearing aid users with PTSD perceive less benefit from hearing aid use on traditional hearing aid outcome measures. Additionally, these hearing aid users were more affected by hyper-arousal, re-experiencing symptoms, and avoidance compared to hearing aid users without PTSD. The clinical implications of this work suggest that hearing aid users with PTSD may need modified hearing aid fittings and/or additional counseling to meet their unique listening needs.
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Kaneko, Kenichi. "Nonlinear Digital Hearing Aid with Near-Instantaneous Amplitude Compression." Kyoto University, 2002. http://hdl.handle.net/2433/150217.
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Wong, Wai-yi Peggy. "Rejection of hearing aid use among Hong Kong elderly." Click to view the E-thesis via HKU Scholors Hub, 2005. http://lookup.lib.hku.hk/lookup/bib/B38279368.
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Thesis (B.Sc)--University of Hong Kong, 2005.<br>"A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2005." Also available in print.
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Blaha, Rebecca. "Hearing aid telecoils : current numbers in the U.S. market /." Connect to resource, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1129571996.
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Thesis (M.A.)--Ohio State University, 2004.<br>Advisor: Stephanie Davidson, Dept. of Speech and Hearing Science. Includes bibliographical references (leaves 34-37). Available online via OhioLINK's ETD Center
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Johnson, Earl E. "Foreword - Hearing Aid Technology: Model-based Concepts and Assessment." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etsu-works/2248.
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Fagelson, Marc A. "Hearing Aid Use for Patients with Posttraumatic Stress Disorder." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/1592.
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The Official Publication of the Canadian Academy of Audiology, Marc Fagelson writes about how awareness and consideration of the special needs of patients with PTSD – the increased need to monitor the acoustical environment
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Johnson, Earl E. "How Do Hearing Aid Dispensers Pick their Buying Preferences." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etsu-works/1970.
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Let's talk beer for a moment. Beginning back in the mid-90s, at the Sandlot microbrewery located within Coors Field in Downtown Denver, a fairly tasty Belgian-style witbier called Bellyslide (a baseball term) was available in small batches. It was a favorite of a few, but ignored by most, and even scorned by some (it was unfiltered). But then, about 6 years ago, Coors gave it a new name— Blue Moon—started producing it in bulk, and rolled it out across the U.S. It became the top-performing beer brand in 2007, and today Blue Moon is closing in on making the top ten list of all domestic beers sold. Why is it so popular? The taste of course, right? Maybe. How about the pretty blue label? Or the fact that it's usually served with an orange slice? Or that Coors disguises it as a “craft beer”? Or, maybe it's just more fun to say “Blue Moon” than “Bud.” As with beer, people also make brand purchase decisions about hearing aids. But there's a difference. In the case of hearing aids, the consumer usually does not select the brand. His or her dispenser does. It's not uncommon to sit down with four different people in private practice and discover that each has a different favorite hearing aid brand. And interestingly, all of them say they picked this particular brand because it is the best. But how can all four brands be the best? Or are they all just the same? Only a few audiologists have conducted research on hearing aid brand preferences. One of them is Earl Johnson, AuD, PhD, an audiologist at Mountain Home, TN, Veterans Affairs Medical Center and assistant professor at East Tennessee State University. While obtaining his PhD at Vanderbilt University with a focus on hearing aid research, Dr. Johnson also studied consumer behavior at Vanderbilt's Owen business school—an unusual combination that has led to much of his research. You've probably also noted his recent book chapters and journal publications related to modern hearing aid technology and hearing aid selection. While this is his debut on Page Ten, Earl is not a new contributor to the Journal. For many years he assisted with HJ'sdispenser surveys and contributed articles on these findings. I'm not sure if Earl drinks Blue Moon because of the orange slice, but I'm quite certain he can provide you some interesting insights on why you have a hearing aid brand preference.
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Udayashankara, V. "DSP Techniques for Performance Enhancement of Digital Hearing Aid." Thesis, Indian Institute of Science, 1995. https://etd.iisc.ac.in/handle/2005/156.
Full textAbstract:
Hearing impairment is the number one chronic disability affecting people in the world. Many people have great difficulty in understanding speech with background noise. This is especially true for a large number of elderly people and the sensorineural impaired persons. Several investigations on speech intelligibility have demonstrated that subjects with sensorineural loss may need a 5-15 dB higher signal-to-noise ratio than the normal hearing subjects. While most defects in transmission chain up to cochlea can nowadays be successfully rehabilitated by means of surgery, the great majority of the remaining inoperable cases are sensorineural hearing impaired, Recent statistics of the hearing impaired patients applying for a hearing aid reveal that 20% of the cases are due to conductive losses, more than 50% are due to sensorineural losses, and the rest 30% of the cases are of mixed origin. Presenting speech to the hearing impaired in an intelligible form remains a major challenge in hearing-aid research today. Even-though various methods have been suggested in the literature for the minimization of noise from the contaminated speech signals, they fail to give good SNR improvement and intelligibility improvement for moderate to-severe sensorineural loss subjects. So far, the power and capability of Newton's method, Nonlinear adaptive filtering methods and the feedback type artificial neural networks have not been exploited for this purpose. Hence we resort to the application of all these methods for improving SNR and intelligibility for the sensorineural loss subjects. Digital hearing aids frequently employ the concept of filter banks. One of the major drawbacks of this techniques is the complexity of computation requiring more number of multiplications. This increases the power consumption. Therefore this Thesis presents the new approach to speech enhancement for the hearing impaired and also the construction of filter bank in Digital hearing aid with minimum number of multiplications. The following are covered in this thesis.
One of the most important application of adaptive systems is in noise cancellation using adaptive filters. The ANC setup requires two input signals (viz., primary and reference). The primary input consists of the sum of the desired signal and noise which is uncorrelated. The reference input consists of mother noise which is correlated in Some unknown way with noise of primary input. The primary signal is obtained by placing the omnidirectional microphone just above one ear on the head of the KEMAR mannikan and the reference signal is obtained by placing the hypercardioid microphone at the center of the vertebral column on the back. Conventional speech enhancement techniques use linear schemes for enhancing speech signals. So far Nonlinear adaptive filtering techniques are not used in hearing aid applications. The motivation behind the use of nonlinear model is that it gives better noise suppression as compared to linear model. This is because the medium through which signals reach the microphone may be highly nonlinear. Hence the use of linear schemes, though motivated by computational simplicity and mathematical tractability, may be suboptimal. Hence, we propose the use of nonlinear models to enhance the speech signals for the hearing impaired: We propose both Linear LMS and Nonlinear second order Volterra LMS schemes to enhance speech signals. Studies conducted for different environmental noise including babble, cafeteria and low frequency noise show that the second-order Volterra LMS performs better compared to linear LMS algorithm. We use measures such as signal-to-noise ratio (SNR),
time plots, and intelligibility tests for performance comparison.
We also propose an ANC scheme which uses Newton's method to enhance speech signals. The main problem associated with LMS based ANC is that their convergence is slow and hence their performance becomes poor for hearing aid applications. The reason for choosing Newton's method is that they have high performance adaptive-filtering methods that often converge and track faster than LMS method. We propose two models to enhance speech signals: one is conventional linear model and the other is a nonlinear model using a second order Volterra function. Development of Newton's type algorithm for linear mdel results in familiar Recursive least square (RLS) algorithm. The performance of both linear and non-linear Newton's algorithm is evaluated for babble, cafeteria and frequency noise. SNR, timeplots and intelligibility tests are used for performance comparison. The results show that Newton's method using Volterra nonlinearity performs better than RLS method.
ln addition to the ANC based schemes, we also develop speech enhancement for the hearing impaired by using the feedback type neural network (FBNN). The main reason is that here we have parallel algorithm which can be implemented directly in hardware. We translate the speech enhancement problem into a neural network (NN) framework by forming an appropriate energy function. We propose both linear and nonlinear FBNN for enhancing the speech signals. Simulated studies on different environmental noise reveal that the FBNN using the Volterra nonlinearity is superior to linear FBNN in enhancing speech signals. We use SNR, time plots, and intelligibility tests for performance comparison.
The design of an effective hearing aid is a challenging problem for sensorineural hearing impaired people. For persons with sensorineural losses it is necessary that the frequency response should be optimally fitted into their residual auditory area. Digital filter enhances the performance of the hearing aids which are either difficult or impossible to realize using analog techniques. The major problem in digital hearing aid is that of reducing power consumption. Multiplication is one of the most power consuming operation in digital filtering. Hence a serious effort has been made to design filter bank with minimum number of multiplications, there by minimizing the power consumption. It is achieved by using Interpolated and complementary FIR filters. This method gives significant savings in the number of arithmetic operations.
The Thesis is concluded by summarizing the results of analysis, and suggesting scope for further investigation
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Udayashankara, V. "DSP Techniques for Performance Enhancement of Digital Hearing Aid." Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/156.
Full textAbstract:
Hearing impairment is the number one chronic disability affecting people in the world. Many people have great difficulty in understanding speech with background noise. This is especially true for a large number of elderly people and the sensorineural impaired persons. Several investigations on speech intelligibility have demonstrated that subjects with sensorineural loss may need a 5-15 dB higher signal-to-noise ratio than the normal hearing subjects. While most defects in transmission chain up to cochlea can nowadays be successfully rehabilitated by means of surgery, the great majority of the remaining inoperable cases are sensorineural hearing impaired, Recent statistics of the hearing impaired patients applying for a hearing aid reveal that 20% of the cases are due to conductive losses, more than 50% are due to sensorineural losses, and the rest 30% of the cases are of mixed origin. Presenting speech to the hearing impaired in an intelligible form remains a major challenge in hearing-aid research today. Even-though various methods have been suggested in the literature for the minimization of noise from the contaminated speech signals, they fail to give good SNR improvement and intelligibility improvement for moderate to-severe sensorineural loss subjects. So far, the power and capability of Newton's method, Nonlinear adaptive filtering methods and the feedback type artificial neural networks have not been exploited for this purpose. Hence we resort to the application of all these methods for improving SNR and intelligibility for the sensorineural loss subjects. Digital hearing aids frequently employ the concept of filter banks. One of the major drawbacks of this techniques is the complexity of computation requiring more number of multiplications. This increases the power consumption. Therefore this Thesis presents the new approach to speech enhancement for the hearing impaired and also the construction of filter bank in Digital hearing aid with minimum number of multiplications. The following are covered in this thesis.
One of the most important application of adaptive systems is in noise cancellation using adaptive filters. The ANC setup requires two input signals (viz., primary and reference). The primary input consists of the sum of the desired signal and noise which is uncorrelated. The reference input consists of mother noise which is correlated in Some unknown way with noise of primary input. The primary signal is obtained by placing the omnidirectional microphone just above one ear on the head of the KEMAR mannikan and the reference signal is obtained by placing the hypercardioid microphone at the center of the vertebral column on the back. Conventional speech enhancement techniques use linear schemes for enhancing speech signals. So far Nonlinear adaptive filtering techniques are not used in hearing aid applications. The motivation behind the use of nonlinear model is that it gives better noise suppression as compared to linear model. This is because the medium through which signals reach the microphone may be highly nonlinear. Hence the use of linear schemes, though motivated by computational simplicity and mathematical tractability, may be suboptimal. Hence, we propose the use of nonlinear models to enhance the speech signals for the hearing impaired: We propose both Linear LMS and Nonlinear second order Volterra LMS schemes to enhance speech signals. Studies conducted for different environmental noise including babble, cafeteria and low frequency noise show that the second-order Volterra LMS performs better compared to linear LMS algorithm. We use measures such as signal-to-noise ratio (SNR),
time plots, and intelligibility tests for performance comparison.
We also propose an ANC scheme which uses Newton's method to enhance speech signals. The main problem associated with LMS based ANC is that their convergence is slow and hence their performance becomes poor for hearing aid applications. The reason for choosing Newton's method is that they have high performance adaptive-filtering methods that often converge and track faster than LMS method. We propose two models to enhance speech signals: one is conventional linear model and the other is a nonlinear model using a second order Volterra function. Development of Newton's type algorithm for linear mdel results in familiar Recursive least square (RLS) algorithm. The performance of both linear and non-linear Newton's algorithm is evaluated for babble, cafeteria and frequency noise. SNR, timeplots and intelligibility tests are used for performance comparison. The results show that Newton's method using Volterra nonlinearity performs better than RLS method.
ln addition to the ANC based schemes, we also develop speech enhancement for the hearing impaired by using the feedback type neural network (FBNN). The main reason is that here we have parallel algorithm which can be implemented directly in hardware. We translate the speech enhancement problem into a neural network (NN) framework by forming an appropriate energy function. We propose both linear and nonlinear FBNN for enhancing the speech signals. Simulated studies on different environmental noise reveal that the FBNN using the Volterra nonlinearity is superior to linear FBNN in enhancing speech signals. We use SNR, time plots, and intelligibility tests for performance comparison.
The design of an effective hearing aid is a challenging problem for sensorineural hearing impaired people. For persons with sensorineural losses it is necessary that the frequency response should be optimally fitted into their residual auditory area. Digital filter enhances the performance of the hearing aids which are either difficult or impossible to realize using analog techniques. The major problem in digital hearing aid is that of reducing power consumption. Multiplication is one of the most power consuming operation in digital filtering. Hence a serious effort has been made to design filter bank with minimum number of multiplications, there by minimizing the power consumption. It is achieved by using Interpolated and complementary FIR filters. This method gives significant savings in the number of arithmetic operations.
The Thesis is concluded by summarizing the results of analysis, and suggesting scope for further investigation
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House, Vicky. "An exploratory study of older peoples' experiences of acquired hearing loss and hearing aid use." Thesis, University of East London, 2003. http://roar.uel.ac.uk/3661/.
Full textAbstract:
The provision of hearing aids is a central component in the rehabilitation of individuals who have acquired a hearing impairment, and costs the NHS a significant sum each year. However, there exist concerns that a large proportion of hearing aids are not used regularly. Given that acquired hearing impairment rises in prevalence in later life, and that research indicates that older people make less use of the hearing aids they are prescribed, it seems important to explore the factors limiting hearing aid use in older people. Previous researchers have examined a range of variables hypothesised to mediate the relationship between amount of hearing aid use and age. However, few have considered how values about the meaning and management of ageing might contextualise the experience of acquired hearing impairment in later life, and impact on hearing aid use. This study uses an interview format and qualitative analysis to explore the interplay between experiences of acquired hearing impairment, hearing aid use and ageing in a sample of older people. The main themes drawn from the data are 1) that hearing impairment is widely constructed as a problem of 'old age', and 2) that decisions about how to manage hearing problems are reflective of values about how to manage ageing and the threat of stigma. Amongst the recommendations made are that professionals should recognise the complexities of managing self- and social-identity for older peoplewith hearing impairments, and should move away from measuring 'successful' hearing management in terms of hours of hearing aid use.
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Nordqvist, Peter. "Sound Classification in Hearing Instruments." Doctoral thesis, KTH, Signaler, sensorer och system, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3777.
Full textAbstract:
A variety of algorithms intended for the new generation of hearing aids is presented in this thesis. The main contribution of this work is the hidden Markov model (HMM) approach to classifying listening environments. This method is efficient and robust and well suited for hearing aid applications. This thesis shows that several advanced classification methods can be implemented in digital hearing aids with reasonable requirements on memory and calculation resources. A method for analyzing complex hearing aid algorithms is presented. Data from each hearing aid and listening environment is displayed in three different forms: (1) Effective temporal characteristics (Gain-Time), (2) Effective compression characteristics (Input-Output), and (3) Effective frequency response (Insertion Gain). The method works as intended. Changes in the behavior of a hearing aid can be seen under realistic listening conditions. It is possible that the proposed method of analyzing hearing instruments generates too much information for the user. An automatic gain controlled (AGC) hearing aid algorithm adapting to two sound sources in the listening environment is presented. The main idea of this algorithm is to: (1) adapt slowly (in approximately 10 seconds) to varying listening environments, e.g. when the user leaves a disciplined conference for a multi-babble coffee-break; (2) switch rapidly(in about 100 ms) between different dominant sound sources within one listening situation, such as the change from the user's own voice to a distant speaker's voice in a quiet conference room; (3) instantly reduce gain for strong transient sounds and then quickly return to the previous gain setting; and (4) not change the gain in silent pauses but instead keep the gain setting of the previous sound source. An acoustic evaluation shows that the algorithm works as intended. A system for listening environment classification in hearing aids is also presented. The task is to automatically classify three different listening environments: 'speech in quiet', 'speech in traffic', and 'speech in babble'. The study shows that the three listening environments can be robustly classified at a variety of signal-to-noise ratios with only a small set of pre-trained source HMMs. The measured classification hit rate was 96.7-99.5% when the classifier was tested with sounds representing one of the three environment categories included in the classifier. False alarm rates were0.2-1.7% in these tests. The study also shows that the system can be implemented with the available resources in today's digital hearing aids. Another implementation of the classifier shows that it is possible to automatically detect when the person wearing the hearing aid uses the telephone. It is demonstrated that future hearing aids may be able to distinguish between the sound of a face-to-face conversation and a telephone conversation, both in noisy and quiet surroundings. However, this classification algorithm alone may not be fast enough to prevent initial feedback problems when the user places the telephone handset at the ear. A method using the classifier result for estimating signal and noise spectra for different listening environments is presented. This evaluation shows that it is possible to robustly estimate signal and noise spectra given that the classifier has good performance. An implementation and an evaluation of a single keyword recognizer for a hearing instrument are presented. The performance for the best parameter setting gives 7e-5 [1/s] in false alarm rate, i.e. one false alarm for every four hours of continuous speech from the user, 100% hit rate for an indoors quiet environment, 71% hit rate for an outdoors/traffic environment and 50% hit rate for a babble noise environment. The memory resource needed for the implemented system is estimated to 1820 words (16-bits). Optimization of the algorithm together with improved technology will inevitably make it possible to implement the system in a digital hearing aid within the next couple of years. A solution to extend the number of keywords and integrate the system with a sound environment classifier is also outlined.<br>QC 20100611
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Han, Na. "Development of a self-report questionnaire to evaluate hearing aid outcomes in Chinese speakers." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40988132.
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