Fitting Frequency-Lowering Signal Processing Applying the American Academy of Audiology Pediatric Amplification Guideline: Updates and Protocols

2016 ◽  
Vol 27 (03) ◽  
pp. 219-236 ◽  
Author(s):  
Susan Scollie ◽  
Danielle Glista ◽  
Julie Seto ◽  
Andrea Dunn ◽  
Brittany Schuett ◽  
...  
Keyword(s):  
Signal Processing ◽  
Frequency Response ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Fine Tuning ◽  
Sensation Level ◽  
Response Level ◽  
Strong Basis ◽  
Wide Range ◽  
Signal Processors

Background: Although guidelines for fitting hearing aids for children are well developed and have strong basis in evidence, specific protocols for fitting and verifying technologies can supplement such guidelines. One such technology is frequency-lowering signal processing. Children require access to a broad bandwidth of speech to detect and use all phonemes including female /s/. When access through conventional amplification is not possible, the use of frequency-lowering signal processing may be considered as a means to overcome limitations. Fitting and verification protocols are needed to better define candidacy determination and options for assessing and fine tuning frequency-lowering signal processing for individuals. Purpose: This work aims to (1) describe a set of calibrated phonemes that can be used to characterize the variation in different brands of frequency-lowering processors in hearing aids and the verification with these signals and (2) determine whether verification with these signal are predictive of perceptual changes associated with changes in the strength of frequency-lowering signal processing. Finally, we aimed to develop a fitting protocol for use in pediatric clinical practice. Study Sample: Study 1 used a sample of six hearing aids spanning four types of frequency lowering algorithms for an electroacoustic evaluation. Study 2 included 21 adults who had hearing loss (mean age 66 yr). Data Collection and Analysis: Simulated fricatives were designed to mimic the level and frequency shape of female fricatives extracted from two sources of speech. These signals were used to verify the frequency-lowering effects of four distinct types of frequency-lowering signal processors available in commercial hearing aids, and verification measures were compared to extracted fricatives made in a reference system. In a second study, the simulated fricatives were used within a probe microphone measurement system to verify a wide range of frequency compression settings in a commercial hearing aid, and 27 adult listeners were tested at each setting. The relation between the hearing aid verification measures and the listener’s ability to detect and discriminate between fricatives was examined. Results: Verification measures made with the simulated fricatives agreed to within 4 dB, on average, and tended to mimic the frequency response shape of fricatives presented in a running speech context. Some processors showed a greater aided response level for fricatives in running speech than fricatives presented in isolation. Results with listeners indicated that verified settings that provided a positive sensation level of /s/ and that maximized the frequency difference between /s/ and /∫/ tended to have the best performance. Conclusions: Frequency-lowering signal processors have measureable effects on the high-frequency fricative content of speech, particularly female /s/. It is possible to measure these effects either with a simple strategy that presents an isolated simulated fricative and measures the aided frequency response or with a more complex system that extracts fricatives from running speech. For some processors, a more accurate result may be achieved with a running speech system. In listeners, the aided frequency location and sensation level of fricatives may be helpful in predicting whether a specific hearing aid fitting, with or without frequency-lowering, will support access to the fricatives of speech.

Flexibility in Frequency Response Shaping and Signal Processing With Analog Hearing Aids

1993 ◽  
Vol 2 (2) ◽  
pp. 29-40 ◽  
Author(s):  
David A. Preves
Keyword(s):  
Signal Processing ◽  
Frequency Response ◽  
Hearing Aids ◽  
Low Voltage ◽  
Hearing Aid ◽  
Digital Signal ◽  
Output Stage ◽  
Analog Electronics ◽  
Output Stages ◽  
Digital Circuitry

Mainly because of packaging size limitations, most amplifiers for in-the-ear (ITE) and in-the-canal (ITC) hearing aids have performed linear processing and had a class A output stage. Recent advances in the miniaturization of analog semiconductor technology have made it possible to package much more sophisticated signal processing circuitry and push-pull and class D output stages in ITE and ITC hearing aids. These advancements have been used in hearing aids to improve sound quality, enhance the speech signal to emphasize weak consonants, provide increased flexibility in frequency response shaping, and reduce the amplification of undesired noise. Although digital programmability offers increased flexibility in hearing aid fittings, in most programmable hearing aid designs it is the analog portion of the circuit rather than the digital portion that performs the signal processing functions. Although "true" digital signal processing holds promise for further dramatic improvements in hearing aid performance, the capabilities of analog electronics are just beginning to be exploited. Through advances in low-voltage CMOS circuitry, analog ITE and even ITC hearing aids are now being made with multiband amplifiers that have relatively steep filter slopes. These small, nonprogrammable hearing instruments are essentially master hearing aids for frequency response shaping that require only a few potentiometers and an ordinary screw-driver for adjustment. Consequently, analog circuitry should not be totally abandoned as yet in favor of digital circuitry.

Effects of Different Frequency Response Strategies Upon Recognition and Preference for Audible Speech Stimuli

1991 ◽  
Vol 34 (5) ◽  
pp. 1185-1196 ◽  
Author(s):  
Amy R. Horwitz ◽  
Christopher W. Turner ◽  
David A. Fabry
Keyword(s):  
Signal Processing ◽  
Frequency Response ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Processing Condition ◽  
Processing Conditions ◽  
Speech Stimuli ◽  
High Pass ◽  
Input Level

The purpose of this study was to examine whether the amount of low. versus high-frequency amplification should change as a function of input level, as is done in some recently developed hearing aids. Adults with high-frequency sensorineural hearing loss served as subjects. Both identification performance and preference judgments for audible CV syllables were assessed as a function of input level for three different signal processing conditions both in quiet and in noise. The first signal processing condition was a conventional high-pass frequency response that did not change its transfer function as the input level increased; the second condition was similar to a typical adaptive frequency response (AFR) hearing aid: a high-pass frequency response that became increasingly high-pass as the input level increased; the third condition was similar to the K-Amp hearing aid recommended by Killion (1988): a high-pass frequency response that became more broadband as the input level increased. Results indicated no significant differences among the three different processing conditions for syllable recognition and a strong listener preference for the syllables presented via the conventional amplification scheme.

scholarly journals Survey of Current Practice in the Fitting and Fine-Tuning of Common Signal-Processing Features in Hearing Aids for Adults

2018 ◽  
Vol 29 (02) ◽  
pp. 118-124 ◽  
Author(s):  
Melinda C. Anderson ◽  
Kathryn H. Arehart ◽  
Pamela E. Souza
Keyword(s):  
Signal Processing ◽  
Noise Reduction ◽  
Hearing Aids ◽  
Current Practice ◽  
Hearing Aid ◽  
The United States ◽  
Fine Tuning ◽  
Directional Microphones ◽  
Survey Results ◽  
Common Signal

AbstractCurrent guidelines for adult hearing aid fittings recommend the use of a prescriptive fitting rationale with real-ear verification that considers the audiogram for the determination of frequency-specific gain and ratios for wide dynamic range compression. However, the guidelines lack recommendations for how other common signal-processing features (e.g., noise reduction, frequency lowering, directional microphones) should be considered during the provision of hearing aid fittings and fine-tunings for adult patients.The purpose of this survey was to identify how audiologists make clinical decisions regarding common signal-processing features for hearing aid provision in adults.An online survey was sent to audiologists across the United States. The 22 survey questions addressed four primary topics including demographics of the responding audiologists, factors affecting selection of hearing aid devices, the approaches used in the fitting of signal-processing features, and the strategies used in the fine-tuning of these features.A total of 251 audiologists who provide hearing aid fittings to adults completed the electronically distributed survey. The respondents worked in a variety of settings including private practice, physician offices, university clinics, and hospitals/medical centers.Data analysis was based on a qualitative analysis of the question responses. The survey results for each of the four topic areas (demographics, device selection, hearing aid fitting, and hearing aid fine-tuning) are summarized descriptively.Survey responses indicate that audiologists vary in the procedures they use in fitting and fine-tuning based on the specific feature, such that the approaches used for the fitting of frequency-specific gain differ from other types of features (i.e., compression time constants, frequency lowering parameters, noise reduction strength, directional microphones, feedback management). Audiologists commonly rely on prescriptive fitting formulas and probe microphone measures for the fitting of frequency-specific gain and rely on manufacturers’ default settings and recommendations for both the initial fitting and the fine-tuning of signal-processing features other than frequency-specific gain.The survey results are consistent with a lack of published protocols and guidelines for fitting and adjusting signal-processing features beyond frequency-specific gain. To streamline current practice, a transparent evidence-based tool that enables clinicians to prescribe the setting of other features from individual patient characteristics would be desirable.

Expectations, Prefitting Counseling, and Hearing Aid Outcome

2009 ◽  
Vol 20 (05) ◽  
pp. 320-334 ◽  
Author(s):  
Gabrielle H. Saunders ◽  
M Samantha Lewis ◽  
Anna Forsline
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
Well Being ◽  
Fine Tuning ◽  
Initial Contact ◽  
High Expectations ◽  
Digital Hearing Aids ◽  
The Impact ◽  
Unrealistic Expectations

Background: Data suggest that having high expectations about hearing aids results in better overall outcome. However, some have postulated that excessively high expectations will result in disappointment and thus poor outcome. It has been suggested that counseling patients with unrealistic expectations about hearing aids prior to fitting may be beneficial. Data, however, are mixed as to the effectiveness of such counseling, in terms of both changes in expectations and final outcome. Purpose: The primary purpose of this study was to determine whether supplementing prefitting counseling with demonstration of real-world listening can (1) alter expectations of new hearing aid users and (2) increase satisfaction over verbal-only counseling. Secondary goals of the study were to examine (1) the relationship between prefitting expectations and postfitting outcome, and (2) the effect of hearing aid fine-tuning on hearing aid outcome. Research Design: Sixty new hearing aid users were fitted binaurally with Beltone Oria behind-the-ear digital hearing aids. Forty participants received prefitting counseling and demonstration of listening situations with the Beltone AVE™ (Audio Verification Environment) system; 20 received prefitting counseling without a demonstration of listening situations. Hearing aid expectations were measured at initial contact and following prefitting counseling. Reported hearing aid outcome was measured after eight to ten weeks of hearing aid use. Study Sample: Sixty new hearing aid users aged between 55 and 81 years with symmetrical sensorineural hearing loss. Intervention: Participants were randomly assigned to one of three experimental groups, between which the prefitting counseling and follow-up differed: Group 1 received prefitting counseling in combination with demonstration of listening situations. Additionally, if the participant had complaints about sound quality at the follow-up visit, the hearing aids were fine-tuned using the Beltone AVE system. Group 2 received prefitting counseling in combination with demonstration of listening situations with the Beltone AVE system, but no fine-tuning was provided at follow-up. Group 3 received prefitting hearing aid counseling that did not include demonstration of listening, and the hearing aids were not fine-tuned at the follow-up appointment. Results: The results showed that prefitting hearing aid counseling had small but significant effects on expectations. The two forms of counseling did not differ in their effectiveness at changing expectations; however, anecdotally, we learned from many participants that that they enjoyed listening to the auditory demonstrations and that they found them to be an interesting listening exercise. The data also show that positive expectations result in more positive outcome and that hearing aid fine-tuning is beneficial to the user. Conclusions: We conclude that prefitting counseling can be advantageous to hearing aid outcome and recommend the addition of prefitting counseling to address expectations associated with quality of life and self-image. The data emphasize the need to address unrealistic expectations prior to fitting hearing aids cautiously, so as not to decrease expectations to the extent of discouraging and demotivating the patient. Data also show that positive expectations regarding the impact hearing aids will have on psychosocial well-being are important for successful hearing aid outcome.

Frequency Response Characteristics of FM Mini-Loop Auditory Trainers

1980 ◽  
Vol 45 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Dianne J. Van Tasell ◽  
Deborah P. Landin
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Microphone Signal ◽  
Response Characteristics ◽  
Amplification System ◽  
Frequency Response Characteristics ◽  
Signal Route ◽  
Public School Classroom ◽  
Performance Results

Personally sized inductance loops (mini-loops) now are available for use with an FM classroom amplification system and the student's personal ear-level hearing aid. Frequency response characteristics of five commercially-available hearing aids were assessed 1) using hearing aid test equipment available in most audiology clinics, with the hearing aid on microphone setting and 2) in a public school classroom, with the hearing aid on telecoil setting and operating with an FM mini-loop system. Clinic and classroom characteristics of the conventional FM receiver-insert earphone auditory trainers also were assessed. Results showed that the personal hearing aids' classroom performance could not be predicted from their clinic performance. Results also showed that gain provided by the environmental microphone circuit of the FM receiver-insert earphone units was uniformly higher than that provided by the teacher-microphone signal route.

scholarly journals Listener Performance with a Novel Hearing Aid Frequency Lowering Technique

2017 ◽  
Vol 28 (09) ◽  
pp. 810-822 ◽  
Author(s):  
Benjamin J. Kirby ◽  
Judy G. Kopun ◽  
Meredith Spratford ◽  
Clairissa M. Mollak ◽  
Marc A. Brennan ◽  
...  
Keyword(s):  
Signal Processing ◽  
Hearing Loss ◽  
Speech Perception ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Sound Quality ◽  
Processing Strategy ◽  
Listening Effort ◽  
At Home

AbstractSloping hearing loss imposes limits on audibility for high-frequency sounds in many hearing aid users. Signal processing algorithms that shift high-frequency sounds to lower frequencies have been introduced in hearing aids to address this challenge by improving audibility of high-frequency sounds.This study examined speech perception performance, listening effort, and subjective sound quality ratings with conventional hearing aid processing and a new frequency-lowering signal processing strategy called frequency composition (FC) in adults and children.Participants wore the study hearing aids in two signal processing conditions (conventional processing versus FC) at an initial laboratory visit and subsequently at home during two approximately six-week long trials, with the order of conditions counterbalanced across individuals in a double-blind paradigm.Children (N = 12, 7 females, mean age in years = 12.0, SD = 3.0) and adults (N = 12, 6 females, mean age in years = 56.2, SD = 17.6) with bilateral sensorineural hearing loss who were full-time hearing aid users.Individual performance with each type of processing was assessed using speech perception tasks, a measure of listening effort, and subjective sound quality surveys at an initial visit. At the conclusion of each subsequent at-home trial, participants were retested in the laboratory. Linear mixed effects analyses were completed for each outcome measure with signal processing condition, age group, visit (prehome versus posthome trial), and measures of aided audibility as predictors.Overall, there were few significant differences in speech perception, listening effort, or subjective sound quality between FC and conventional processing, effects of listener age, or longitudinal changes in performance. Listeners preferred FC to conventional processing on one of six subjective sound quality metrics. Better speech perception performance was consistently related to higher aided audibility.These results indicate that when high-frequency speech sounds are made audible with conventional processing, speech recognition ability and listening effort are similar between conventional processing and FC. Despite the lack of benefit to speech perception, some listeners still preferred FC, suggesting that qualitative measures should be considered when evaluating candidacy for this signal processing strategy.

Evaluation of an Articulation-Index Based Model for Predicting the Effects of Adaptive Frequency Response Hearing Aids

1990 ◽  
Vol 33 (4) ◽  
pp. 676-689 ◽  
Author(s):  
David A. Fabry ◽  
Dianne J. Van Tasell
Keyword(s):  
Transfer Function ◽  
Frequency Response ◽  
Hearing Aids ◽  
Background Noise ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Hearing Impaired ◽  
Articulation Index ◽  
Intelligibility Ratings ◽  
High Pass

The Articulation Index (AI) was used to evaluate an “adaptive frequency response” (AFR) hearing aid with amplification characteristics that automatically change to become more high-pass with increasing levels of background noise. Speech intelligibility ratings of connected discourse by normal-hearing subjects were predicted well by an empirically derived AI transfer function. That transfer function was used to predict aided speech intelligibility ratings by 12 hearing-impaired subjects wearing a master hearing aid with the Argosy Manhattan Circuit enabled (AFR-on) or disabled (AFR-off). For all subjects, the AI predicted no improvements in speech intelligibility for the AFR-on versus AFR-off condition, and no significant improvements in rated intelligibility were observed. The ability of the AI to predict aided speech intelligibility varied across subjects. However, ratings from every hearing-impaired subject were related monotonically to AI. Therefore, AI calculations may be used to predict relative—but not absolute—levels of speech intelligibility produced under different amplification conditions.

Evaluation of the Self-Fitting Process with a Commercially Available Hearing Aid

2017 ◽  
Vol 28 (02) ◽  
pp. 109-118 ◽  
Author(s):  
Elizabeth Convery ◽  
Gitte Keidser ◽  
Mark Seeto ◽  
Margot McLelland
Keyword(s):  
Hearing Loss ◽  
Success Rate ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Low Cost ◽  
The Self ◽  
Fine Tuning ◽  
Successful Outcome ◽  
Fitting Procedure ◽  
Fitting Hearing Aids

Background: Hearing aids and personal sound amplification products that are designed to be self-fitted by the user at home are becoming increasingly available in the online marketplace. While these devices are often marketed as a low-cost alternative to traditional hearing health-care, little is known about people’s ability to successfully use and manage them. Previous research into the individual components of a simulated self-fitting procedure has been undertaken, but no study has evaluated performance of the procedure as a whole using a commercial product. Purpose: To evaluate the ability of a group of adults with a hearing loss to set up a pair of commercially available self-fitting hearing aids for their own use and to investigate factors associated with a successful outcome. Research Design: An interventional study that used regression analysis to identify potential contributors to the outcome. Study Sample: Forty adults with mild to moderately severe hearing loss participated in the study: 20 current hearing aid users (the “experienced” group) and 20 with no previous amplification experience (the “new” group). Twenty-four participants attended with partners, who were present to offer assistance with the study task as needed. Data Collection and Analysis: Participants followed a set of written, illustrated instructions to perform a multistep self-fitting procedure with a commercially available self-fitting hearing aid, with optional assistance from a lay partner. Standardized measures of cognitive function, health literacy, locus of control, hearing aid self-efficacy, and manual dexterity were collected. Statistical analysis was performed to examine the proportion of participants in each group who successfully performed the self-fitting procedure, factors that predicted successful completion of the task, and the contributions of partners to the outcome. Results: Fifty-five percent of participants were able to successfully perform the self-fitting procedure. Although the same success rate was observed for both experienced and new participants, the majority of the errors relating to the hearing test and the fine-tuning tasks were made by the experienced participants, while all of the errors associated with physically customizing the hearing aids and most of the insertion errors were made by the new participants. Although the majority of partners assisted in the self-fitting task, their contributions did not significantly influence the outcome. Further, no characteristic or combination of characteristics reliably predicted which participants would be successful at the self-fitting task. Conclusions: Although the majority of participants were able to complete the self-fitting task without error, the provision of knowledgeable support by trained personnel, rather than a fellow layperson, would most certainly increase the proportion of users who are able to achieve success. Refinements to the instructions and the physical design of the hearing aid may also serve to improve the success rate. Further evaluation of the range of self-fitting hearing aids that are now on the market should be undertaken.

Low-Frequency Response of Hearing Aids and Judgments of Aided Speech Quality

1980 ◽  
Vol 45 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Jerry L. Punch ◽  
Edwin L. Beck
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Paired Comparison ◽  
Hearing Aid ◽  
Cutoff Frequency ◽  
Low Frequency ◽  
Hearing Impaired ◽  
Connected Discourse ◽  
Experimental Trials

Connected discourse was processed by a master hearing aid via two channels that were independently adjusted to seven discrete settings of low-cutoff frequency. Signals were tape-recorded and played back in a paired-comparison format to 12 listeners with gradually sloping sensorineural hearing loss, who selected the speech channel preferred for its sound quality. Four experimental trials were administered, each of which consisted of 21 randomized paired conditions. Results across the four trials revealed high intersubject and intrasubject response agreement. Listeners indicated strong and systematic preferences for speech reproduced by circuitry having progressively extended low-frequency emphasis. Findings confirm earlier experimental observations that hearing-impaired listeners are capable of making repeatable paired-comparison preference judgments of the quality of hearing-aid processed speech. Additionally, results demonstrate definitively that low-cutoff frequency is sufficiently robust to be regarded as the probable source of a potent perceptual basis for such judgments. The clinical implication is that hearing-impaired listeners can be expected to exhibit strong preferences for the quality of speech reproduced by hearing aids having relatively extended low-frequency response.

scholarly journals Wind Noise Management in Hearing Aids

2021 ◽  
Vol 42 (03) ◽  
pp. 248-259
Author(s):  
Petri Korhonen
Keyword(s):  
Signal Processing ◽  
Adverse Effects ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Wind Noise ◽  
Outdoor Activities ◽  
Signal Processing Algorithms ◽  
Turbulent Airflow ◽  
Processing Algorithms ◽  
Noise Management

AbstractMany hearing aid users are negatively impacted by wind noise when spending time outdoors. Turbulent airflow around hearing aid microphones caused by the obstruction of wind can result in noise that is not only perceived as annoying but may also mask desirable sounds in the listening environment, such as speech. To mitigate the adverse effects of wind noise, hearing aid developers have introduced several technological solutions to reduce the amount of wind noise at the hearing aid output. Some solutions are based on mechanical modifications; more recently, sophisticated signal processing algorithms have also been introduced. By offering solutions to the wind noise problem, these signal processing algorithms can promote more optimal use of hearing aids during outdoor activities. This article reviews how wind noise is generated in hearing aids, outlines the technological challenges in wind noise management, and summarizes the technological solutions that have been proposed and/or implemented in modern hearing aids.

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