Variability of Gain Versus Frequency Characteristics in Hearing Aids

1967 ◽  
Vol 10 (2) ◽  
pp. 377-383 ◽  
Author(s):  
Roger N. Kasten ◽  
Stephen H. Lotterman ◽  
Sally G. Revoile
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Frequency Characteristics ◽  
Response Curves ◽  
Discrete Frequency ◽  
The Mean ◽  
Frequency Curves

Full-on gain versus frequency response curves were obtained from ten different hearing aid models using 15 samples of each model. A mean curve and the range of responses from 20 discrete frequency points were plotted for each model along with the manufacturer’s published curve at full-on gain values. While about half of the models tested showed good intragroup consistency, the variability of gain characteristics for the remaining models was large. The mean gain versus frequency curves of the sample aids differed from those published by the manufacrurer for about half of the models tested.

scholarly journals Difference between the Default Telecoil (T-Coil) and Programmed Microphone Frequency Response in Behind-the-Ear (BTE) Hearing Aids

2012 ◽  
Vol 23 (05) ◽  
pp. 366-378 ◽  
Author(s):  
Daniel B. Putterman ◽  
Michael Valente
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Repeated Measures ◽  
Mixed Model ◽  
Hearing Aid ◽  
Primary Concern ◽  
The Real ◽  
Repeated Measures Design ◽  
Significant Difference ◽  
The Mean

Background: A telecoil (t-coil) is essential for hearing aid users when listening on the telephone because using the hearing aid microphone when communicating on the telephone can cause feedback due to telephone handset proximity to the hearing aid microphone. Clinicians may overlook the role of the t-coil due to a primary concern of matching the microphone frequency response to a valid prescriptive target. Little has been published to support the idea that the t-coil frequency response should match the microphone frequency response to provide “seamless” and perhaps optimal performance on the telephone. If the clinical goal were to match both frequency responses, it would be useful to know the relative differences, if any, that currently exist between these two transducers. Purpose: The primary purpose of this study was to determine if statistically significant differences were present between the mean output (in dB SPL) of the programmed microphone program and the hearing aid manufacturer's default t-coil program as a function of discrete test frequencies. In addition, pilot data are presented on the feasibility of measuring the microphone and t-coil frequency response with real-ear measures using a digital speech-weighted noise. Research Design: A repeated-measures design was utilized for a 2-cc coupler measurement condition. Independent variables were the transducer (microphone, t-coil) and 11 discrete test frequencies (15 discrete frequencies in the real-ear pilot condition). Study Sample: The study sample was comprised of behind-the-ear (BTE) hearing aids from one manufacturer. Fifty-two hearing aids were measured in a coupler condition, 39 of which were measured in the real-ear pilot condition. Hearing aids were previously programmed and verified using real-ear measures to the NAL-NL1 (National Acoustic Laboratories—Non-linear 1) prescriptive target by a licensed audiologist. Data Collection and Analysis: Hearing aid output was measured with a Fonix 7000 hearing aid analyzer (Frye Electronics, Inc.) in a HA-2 2-cc coupler condition using a pure-tone sweep at an input level of 60 dB SPL with the hearing aid in the microphone program and 31.6 mA/M in the t-coil program. A digital speech weighted noise input signal presented at additional input levels was used in the real-ear pilot condition. A mixed-model repeated-measures analysis of variance (ANOVA) and the Tukey Honestly Significant Difference (HSD) post hoc test were utilized to determine if significant differences were present in performance across treatment levels. Results: There was no significant difference between mean overall t-coil and microphone output averaged across 11 discrete frequencies (F(1,102) = 0, p < 0.98). A mixed-model repeated-measures ANOVA revealed a significant transducer by frequency interaction (F(10,102) = 13.0, p < 0.0001). Significant differences were present at 200 and 400 Hz where the mean t-coil output was less than the mean microphone output, and at 4000, 5000, and 6300 Hz where the mean t-coil output was greater than the mean microphone output. Conclusions: The mean t-coil output was significantly lower than the mean microphone output at 400 Hz, a frequency that lies within the typical telephone bandwidth of 300–3300 Hz. This difference may partially help to explain why some patients often complain the t-coil fails to provide sufficient loudness for telephone communication.

A Follow-Up Study of the CROS Hearing Aid

1972 ◽  
Vol 37 (1) ◽  
pp. 113-117 ◽  
Author(s):  
Hedda Aufricht
Keyword(s):  
Hearing Aids ◽  
Hearing Aid ◽  
Unilateral Hearing Loss ◽  
Conversational Speech ◽  
Noisy Environment ◽  
Follow Up Study ◽  
Speech Distortion ◽  
Male Veterans ◽  
The Mean

A recent development in hearing aids, the contralateral routing of signals (CROS), makes it possible to provide amplification for persons with unilateral hearing loss. In 1967, a CROS eyeglass hearing aid was placed on government contract and made available to veterans. To study the efficiency of the CROS, a follow-up questionnaire was sent to 60 male veterans who had been fitted with this aid. All had demonstrated unilateral hearing losses, and the mean threshold for the speech frequencies (500–2000 Hz) in the good ear was 24 dB. The 54 replies (90%) indicated that 85% wore the aid, liked it, and derived benefit from it; 15% neither liked nor wore the aid. The CROS appeared to be most helpful in listening to conversational speech and at work, and most disturbing in a noisy environment. The complaints about the aid fell into major categories: 33% objected to its poor fit and construction and 11% were disturbed by speech distortion. The CROS aid has been a useful addition to the hearing-aid stock at the clinic reported here. It has expanded the program by providing amplification to veterans who could not be fitted with the conventional stock of aids.

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.

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.

Measuring Hearing Aid Outcomes Using the Satisfaction with Amplification in Daily Life (SADL) Questionnaire: Australian Data

2005 ◽  
Vol 16 (06) ◽  
pp. 383-402 ◽  
Author(s):  
Margaret Uriarte ◽  
Lauren Denzin ◽  
Amy Dunstan ◽  
Jillian Sellars ◽  
Louise Hickson
Keyword(s):  
Hearing Aids ◽  
Normative Data ◽  
Daily Life ◽  
Hearing Aid ◽  
Level Of Satisfaction ◽  
Digitally Programmable ◽  
Australian Sample ◽  
The Mean ◽  
The Relationship ◽  
The U.S

The aims of this study were to investigate hearing aid satisfaction for a group of older Australians fitted with government-funded hearing aids using the Satisfaction with Amplification in Daily Life (SADL) questionnaire; to compare the Australian data gathered with the provisional normative data reported by Cox and Alexander (1999); and to investigate the relationship between SADL satisfaction and several participant variables, hearing aid variables, and other outcome measures.The SADL questionnaire and a Client Satisfaction Survey (CSS) were distributed by mail to 1284 adults fitted with government-funded hearing aids three to six months previously. 1014 surveys were returned. The mean age of participants was 75.32 years; 54.4% of participants were male, and 54.8% were fitted binaurally. Participants were fitted primarily with digitally programmable hearing aids of various styles (22.5% BTEs, 34.8% ITEs, 41.8% ITCs, 0.9% nonstandard [NS] devices).Overall, participants reported a considerable level of satisfaction with their devices. SADL Global and subscale scores were significantly higher for the Australian sample than the U.S. norms described by Cox and Alexander (1999).

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.

Comparisons of Client and Clinician Views of the Importance of Factors in Client-Clinician Interaction in Hearing Aid Purchase Decisions

2015 ◽  
Vol 26 (03) ◽  
pp. 247-259 ◽  
Author(s):  
Laya Poost-Foroosh ◽  
Mary Beth Jennings ◽  
Margaret F. Cheesman
Keyword(s):  
Decision Making ◽  
Shared Decision Making ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Purchase Decisions ◽  
Shared Decision ◽  
Centered Care ◽  
Importance Ratings ◽  
The Mean ◽  
Client Needs

Background: Despite clinical recognition of the adverse effects of acquired hearing loss, only a small proportion of adults who could benefit use hearing aids. Hearing aid adoption has been studied in relationship to client-related and hearing aid technology–related factors. The influence of the client-clinician interaction in the decision to purchase hearing aids has not been explored in any depth. Purpose: Importance ratings of a sample of adults having a recent hearing aid recommendation (clients) and hearing healthcare professionals (clinicians) from across Canada were compared on factors in client-clinician interactions that influence hearing aid purchase decisions. Research Design: A cross-sectional approach was used to obtain online and paper-based concept ratings. Data Collection and Analysis: Participants were 43 adults (age range, 45–85 yr) who had received a first hearing aid recommendation in the 3 mo before participation. A total of 54 audiologists and 20 hearing instrument practitioners from a variety of clinical settings who prescribed or dispensed hearing aids completed the concept-rating task. The task consisted of 122 items that had been generated via concept mapping in a previous study and which resulted in the identification of eight concepts that may influence hearing aid purchase decisions. Participants rated “the importance of each of the statements in a person’s decision to purchase a hearing aid” on a 5-point Likert scale, from 1 = minimally important to 5 = extremely important. For the initial data analysis, the ratings for each of the items included in each concept were averaged for each participant to provide an estimate of the overall importance rating of each concept. Multivariate analysis of variance was used to compare the mean importance ratings of the clients to the clinicians. Ratings of individual statements were also compared in order to investigate the directionality of the importance ratings within concepts. Results: There was a significant difference in the mean ratings for clients and clinicians for the concepts understanding and meeting client needs, conveying device information by clinician, supporting choices and shared decision making, and factors in client readiness. Three concepts—understanding and meeting client needs, conveying device information by clinician, and supporting choices and shared decision making—were rated as more important by clients than by clinicians. One concept (ie, factors in client readiness) was rated as more important by clinicians than by clients. Conclusions: The concepts rated as most important by clients and clinicians are consistent with components of several existing models of client-centered and patient-centered care. These concepts reflect the clients’ perception of the importance of their involvement in the decision-making process. A preliminary model of client-centered care within the hearing aid uptake process and implications for clinical audiology are described.

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.

Performance of Individual Hearing Aids Utilizing Microphone and Induction Coil Input

1971 ◽  
Vol 14 (2) ◽  
pp. 365-371 ◽  
Author(s):  
Richard J. Sung ◽  
William R. Hodgson
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Hearing Aid ◽  
Harmonic Distortion ◽  
Physical Characteristics ◽  
Induction Coil ◽  
Body Type ◽  
High Frequency Response ◽  
Physical Measurements

Physical measurements of gain, maximum power output, frequency response, and harmonic distortion were made on each of two body-type hearing aids on both the microphone and induction coil settings. In addition, we investigated speech intelligibility through each aid, for both acoustic and magnetic input, using 32 normal-hearing subjects. Our findings indicated that different hearing aids provide different sensitivity for loop induction. For a given hearing aid, physical characteristics varied between the microphone and the telephone coil settings. The intelligibility of speech produced by a given mode of signal input, either microphone or telephone coil, was dependent on physical characteristics of the hearing aid. The usable high-frequency response and the configuration of the response curve in the region of 1500 to 3000 Hz appeared to be associated with the intelligibility of monosyllabic words.

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