Academic literature on the topic 'Hearing aids – Calibration'

Background. Functioning of nonlinear hearing aids varies with characteristics of input stimuli. In the past decade, aided speech evoked cortical auditory evoked potentials (CAEPs) have been proposed for validation of hearing aid fittings. However, unlike in running speech, phonemes presented as stimuli during CAEP testing are preceded by silent intervals of over one second. Hence, the present study aimed to compare if hearing aids process phonemes similarly in running speech and in CAEP testing contexts.Method. A sample of ten hearing aids was used. Overall phoneme level and phoneme onset level of eight phonemes in both contexts were compared at three input levels representing conversational speech levels.Results. Differences of over 3 dB between the two contexts were noted in one-fourth of the observations measuring overall phoneme levels and in one-third of the observations measuring phoneme onset level. In a majority of these differences, output levels of phonemes were higher in the running speech context. These differences varied across hearing aids.Conclusion. Lower output levels in the isolation context may have implications for calibration and estimation of audibility based on CAEPs. The variability across hearing aids observed could make it challenging to predict differences on an individual basis.

Introduction It is notoriously difficult to obtain a perfect fitting of hearing aids (HAs) for children as they often struggle to understand their hearing loss well enough to discuss the fitting adequately with their audiologist. Dartanan is an ‘edutainment’ game developed to help children understand the functions of their HA in different sound contexts. Dartanan also has elements of a leisure game for all children, in order to create an inclusive activity. Methods Game prototypes were evaluated during two formative evaluations and a summative evaluation. In total 106 children with and without hearing loss in Italy, Spain and the UK played Dartanan. A built-in virtual HA enabled children with hearing loss to use headphones to play. Results and conclusions: During the formative stages, feedback was discussed during focus groups on factors such as the audiological aspects, the extent to which children learned about HA functions, accessibility and usability, and this feedback was presented to the developers. After redevelopment, a summative evaluation was performed using an online survey. It was concluded that the game had met the goals of helping children understand their HA functionalities and providing an inclusive activity. User-evaluations were crucial in the development of the app into a useful and useable service.

Background: In-situ audiometry is a hearing aid feature that enables the measurement of hearing threshold levels through the hearing instrument using the built-in sound generator and the hearing aid receiver. This feature can be used in hearing aid fittings instead of conventional pure-tone audiometry (PTA), particularly in places where no standard audiometric equipment is available. Differences between conventional and in-situ thresholds are described and discussed for some particular hearing aids. No previous investigation has measured and compared these differences for a number of current hearing aid models by various manufacturers across a wide range of hearing losses. Purpose: The purpose of this study was to perform a model-based comparison of conventionally and in-situ measured hearing thresholds. Data were collected for a range of hearing aid devices to study and generalize the effects that may occur under clinical conditions. Research Design: Research design was an experimental and regression study. Study Sample: A total of 30 adults with sensorineural hearing loss served as test persons. They were assigned to three subgroups of 10 subjects with mild (M), moderate to severe (MS), and severe (S) sensorineural hearing loss. Intervention: All 30 test persons underwent both conventional PTA and in-situ audiometry with four hearing aid models by various manufacturers. Data Collection and Analysis: The differences between conventionally and in-situ measured hearing threshold levels were calculated and evaluated by an exploratory data analysis followed by a sophisticated statistical modeling process. Results: At 500 and 1500 Hz, almost all threshold differences (conventional PTA minus in-situ data) were negative, i.e., in the low to mid frequencies, hearing loss was overestimated by most devices relative to PTA. At 4000 Hz, the majority of differences (7 of 12) were positive, i.e., in the frequency range above 1500 Hz, hearing loss was frequently underestimated. As hearing loss increased (M→MS→S), the effect of the underestimation decreased. At 500 and 1500 Hz, Resound devices showed the smallest threshold deviations, followed by Phonak, Starkey, and Oticon instruments. At 4000 Hz, this observed pattern partly disappeared and Starkey and Oticon devices showed a reversed effect with increasing hearing loss (M→MS→S). Because of high standard errors for the estimates, only a few explicit rankings of the devices could be established based on significant threshold differences (5% level). Conclusions: Differences between conventional PTA and in-situ threshold levels may be attributed to (1) frequency, (2) device/hearing loss, and (3) calibration/manufacturer effects. Frequency effects primarily resulting in an overestimation of hearing loss by in-situ audiometry in the low and mid frequencies are mainly due to sound drain-off through vents and leaks. Device/hearing loss effects may be due to leakage as well as boundary effects because in-situ audiometry is confined to a limited measurement range. Finally, different calibration approaches may result in different offset levels between PTA and in-situ audiometry calibration. In some cases, the observed threshold differences of up to 10–15 dB may translate to varied hearing aid fittings for the same user depending on how hearing threshold levels were measured.

Purpose: To investigate the test-retest reliability of real-ear aided response (REAR) measures in open and closed hearing aid fittings in children using appropriate probe-microphone calibration techniques (stored equalization for open fittings and concurrent equalization for closed fittings). Research Design: Probe-microphone measurements were completed for two mini-behind-the-ear (BTE) hearing aids which were coupled to the ear using open and closed eartips via thin (0.9 mm) tubing. Before probe-microphone testing, the gain of each of the test hearing aids was programmed using an artificial ear simulator (IEC 711) and a Knowles Electronic Manikin for Acoustic Research to match the National Acoustic Laboratories–-Non-Linear, version 1 targets for one of two separate hearing loss configurations using an Audioscan Verifit. No further adjustments were made, and the same amplifier gain was used within each hearing aid across both eartip configurations and all participants. Probe-microphone testing included real-ear occluded response (REOR) and REAR measures using the Verifit's standard speech signal (the carrot passage) presented at 65 dB sound pressure level (SPL). Two repeated probe-microphone measures were made for each participant with the probe-tube and hearing aid removed and repositioned between each trial in order to assess intrasubject measurement variability. These procedures were repeated using both open and closed domes. Study Sample: Thirty-two children, ages ranging from 4 to 14 yr. Results: The test-retest standard deviations for open and closed measures did not exceed 4 dB at any frequency. There was also no significant difference between the open (stored equalization) and closed (concurrent equalization) methods. Reliability was particularly similar in the high frequencies and was also quite similar to that reported in previous research. There was no correlation between reliability and age, suggesting high reliability across all ages evaluated. Conclusions: The findings from this study suggest that reliable probe-microphone measurements are obtainable on children 4 yr and older for both traditional unvented and open-canal hearing aid fittings. These data suggest that clinicians should not avoid fitting open technology to children as young as 4 y because of concerns regarding the reliability of verification techniques.

A then-test technique was used to investigate the possibility of a response shift in the Glasgow hearing aid benefit profile (GHABP). Following completion of part 1 of the GHABP, 16 adults were invited for hearing-aid follow up appointments. In accordance with then-test technique, participants were asked to think back to before they had their hearing-aids fitted and the GHABP part 1 was completed again to re-establish the disability and handicap scores. These scores were then compared with the initial GHABP part I scores. Paired T testing and Wilcoxon Rank tests were carried out to investigate the statistical significance of the response shift effect. Statistically significant differences were seen between initial and retrospective GHABP (disability) scores using t test. No significant differences could be seen between the initial and retrospective handicap scores. Results suggest participants may have demonstrated a possible response shift phenomenon with the disability construct of the GHABP questionnaire, related to a possible re-calibration effect or a denial of disability effect. This exploratory study suggests that the GHABP questionnaire may be subject to a response shift phenomena. We suggest that further more robust studies are completed to verify this and recommend that this could have psychological impact on participants when explaining the results of the outcome measure and may affect hearing aid use. There is also potential for this phenomenon to affect global GHABP scores specifically when demonstrating to stakeholders the overall success of an audiology service.

Cochlear implantation is a well-established therapeutic approach for deaf or hearing-impaired patients. After the medical intervention, which aims to restore hearing, subjects undergo rehabilitation procedures in order to cure instructional disadvantages, problematic schooling circumstances, or deficits in their sociability. Essential physical, mental, social, and cognitive skills are taken into perspective, as the prerequisite of a notable aptitude determines the suitability of a subject to get professional and communal roles. Quality of life, as an indicator, provides the metrics that demonstrate the level of adoption with established norms.

Cochlear implantation is a well-established therapeutic approach for deaf or hearing-impaired patients. After the medical intervention, which aims to restore hearing, subjects undergo rehabilitation procedures in order to cure instructional disadvantages, problematic schooling circumstances, or deficits in their sociability. Essential physical, mental, social, and cognitive skills are taken into perspective, as the prerequisite of a notable aptitude determines the suitability of a subject to get professional and communal roles. Quality of life, as an indicator, provides the metrics that demonstrate the level of adoption with established norms.

Measurements of the fluctuating wall pressure field across the transition region of a flat plate zero pressure gradient boundary layer have been performed with a 64-element linear array of sub-miniature hearing-aid microphones. The measurements provide a unique description of the formation, convection, and growth of turbulent spots in the transition zone and insight into a potential source of low-wavenumber energy. A model for the nonhomogeneous wavenumber-frequency spectrum has been formulated based on the observed spatio-temporal properties of the field. Measured array-averaged wavenumber-frequency spectral levels for the transitional boundary layer collapse with fully turbulent spectra in the vicinity of the convective ridge when scaled by intermittency, similar to previous findings for single point spectra. The transition zone convective ridge is broader, however, consistent with the notion of rapidly evolving (versus equilibrium) structures. Insight into the low-wavenumber portions of the spectra requires an improved array phase calibration. Wavelet based transform methods are being pursued to understand the evolution of spectral components during spot formation and to resolve the space-varying wavenumber content of the field.